Voyager 1 Passes 100 AU from the Sun

An anonymous reader writes "Yesterday, Voyager 1 passed 100 astronomical units from the sun as it continues operating after nearly 30 years in space. That is about 15 billion kilometers or 9.3 billion miles as it travels about 1 million miles per day. Scientists still hope it will find the edge of the solar system and get into interstellar space."

Comments

Poor V-ger

[Recovering Hater]

I wonder how long until it comes back carrying half the solar system with it looking for it's maker?

Re:Poor V-ger

[__aaclcg7560]

According to the movie, about another 200 years. Meanwhile, aliens with pointy years will be dropping by in another 50 years to find a restroom.

Re:Poor V-ger

[Anonymous Coward]

wow, beat me too it.

Re:Poor V-ger

[browe]

Lets do the math.... It took 30 years to get there. So, if an ET finds it today and decides to take action, I guess your earliest answer will come just in time for football season in the fall of 2036. Maybe JoPa will still be coaching.

Re:Poor V-ger

[Lurker2288]

Nah, if there are ETs out there capable of detecting it, retrieving it, and figuring out where it came from, chances are they can manage to go a little faster than a probe that's been coasting on a gravity slingshot for 30-odd years.

Re:Poor V-ger

[Pharmboy]

I wonder how long until it comes back carrying half the solar system with it looking for it's maker?

Or gets to the end where the gorilla throws barrels at you.

Re:Poor V-ger

[westyx]

That's what random wormholes are for.

Re:Poor V-ger

[revolu7ion]

but scotty is dead...

Re:Poor V-ger

[Jafafa Hots]

That's Voyager SIX!! I'm not even a trekkie and I know that much! ;)

Re:Poor V-ger

[bestiarosa]

I wonder how long until the NASA scientists will lose the recordings of the Voyager's data.

Re:Poor V-ger

[Crayon Kid]

What I want to know about Voyager is: does it run Linux?

Re:Poor V-ger

[teflaime]

No, it's stuck with BSDi.

Where do scientists think the edge is...

[Mc_Anthony]

How many more AUs to scientists think Voyager still has to travel before it reaches the edge, or do we not have a good estimation of that distance?

If I'm a space science noob does that make me a "Universal Noob"?

Re:Where do scientists think the edge is...

[Symp0sium]

How many AU's must a spacecraft pass by
Before you call it V'ger?
Yes, 'n' how many orbits must a NASA sucess sail
Before it gets to its first Pluton?
Yes, 'n' how many decades must the RTG's half-life be
Before they're forever decayed?
The answer, my friend, is travellin' at one million mpd,
The answer is travellin' at one million mpd.

Re:Where do scientists think the edge is...

[polymath69]

To the best of my knowledge, friend, there is more than one definition of "edge".

There's the magnetopause, where the magnetic influence of other stars predominates that of our own... to my knowledge, both Vger's are beyond this point.

There's the heliopause, where the outward flow of solar gases finally doesn't have enough pressure to overcome whatever's coming its way... to my knowledge, neither Vger has hit this point yet.

And considering that both Vgers were both launched basically along the ecliptic, neither one is likely to be headed towards the closest heliographic star, which is in the Southern hemisphere (Terran, not ecliptical; but if something's never north of one, it's probably never north of the other.) Neither is the shape of either 'pause likely to be spherical; they would depend upon the distances, relative magnetic field strength, and relative gaseous flux of every star around us.

Finding these things out, in some small way, is one reason I'm very glad the Voyager spacecraft have lasted so long beyond their design dates.

Re:Where do scientists think the edge is...

[paynesmanor]

They don't think there is a edge. Think of it like being inside a large box full of space. Well whats on the other side of the box wall? A larger box?

The nearest star is 4.2 light years away.

A light-year Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More p recisely, one light-year is equal to 9,500,000,000,000 kilometers.
The AU is defined as the average distance between the Earth and the Sun. It is approximately 150 million km (93 million miles). Mercury can be said to be about 1/3 of an AU from the Sun and Pluto averages about 40 AU from the Sun.

9,500,000,000,000 km Light year
    150,000,000,000 km away

So it will take it, Approx 7,988 more years to get to the nearest star.

Check this Nasa pic out....
http://antwrp.gsfc.nasa.gov/apod/ap060807.html

Re:Where do scientists think the edge is...

[ahsile]

We're talking about the edge of the solar system, not the nearest star.

Re:Where do scientists think the edge is...

[stevesliva]

And considering that both Vgers were both launched basically along the ecliptic,

Voyager 1 turned above the plane via Saturn gravity assist to pass by Titan. It's well above ecliptic.

Re:Where do scientists think the edge is...

[paynesmanor]

Those with comments should think before they post. I believe he was talking about the edge of the Universe.. As the star comment was just to put it all in perspective. Conisdering that pluto is only 40 AU from the sun. And the probe is 100 AU from the sun. I would say that its past the solar system, and on its way through the galaxy... Thats gotta be a real small box for you..

Re:Where do scientists think the edge is...

[Anonymous Coward]

As a practical joke, the crew of one of the very first Earth-built warp-capable spacecraft dumped Voyager 6 into what they thought was a normal wormhole that would take it to an inhabited solar system a few hundred light years away, but really was a transwarp corridor to a solar system in a distant galaxy occupied by living machines...

Re:Where do scientists think the edge is...

[ahsile]

Please do some research. There is no agreed upon edge of the solar system. The heliosphere, for example, extends far beyond pluto: http://en.wikipedia.org/wiki/Heliosphere

There are other measures as well. We all know that one of our probes isn't going to reach the end of the universe, or even another star.

Can we still ping it?

[HaloZero]

I recall some time ago reading that the total-return-time for an ICMP_ECHO_RESPONSE from voyager 1 was something in the scale of 29 minutes. I'm hoping we're still getting useful data from these devices.

Re:Can we still ping it?

[pe1chl]

29 minutes? More like 1600...

Re:Can we still ping it?

[Elder Entropist]

More like 26-27 hours.

Re:Can we still ping it?

[thebudgie]

IIRC the earth is about 8 minutes from the sun, so 100AU would be around 800 minutes, right?

Re:Can we still ping it?

[Ex Machina]

100 Astronomical Units = 831.675359 light minutes

I think that exceeds the maximum RTT for TCP.

Re:Can we still ping it?

[andrewman327]

I don't know where you are getting your data, but it takes substancially longer than 29 minutes! From NASA:

So how far are the Voyager spacecraft from Earth? The answer could take the form of miles or kilometers...billions of miles or kilometers. To put this large distance into a different prospective, as of January 5, 2004, a command signal sent from one of the DSN antennas, traveling at the speed of light towards Voyager-1, takes about 12 hours and 39 minutes, to reach Voyager-1's receiver. Compare this to sending a signal to Mars, a command going to the Mars Global Surveyor spacecraft, in orbit around Mars would only take about 15 minutes.

Considering the original expectations of the probe, we are getting amazing data! When launched, no one expected there to be any signal at all being transmitted after this long. This is a major feat of engineering.

Technology is interesting. It has taken 30 years to move a record this far into space. Compare that to an MP3, which can be streamed that same distance in only half a day!

Re:Can we still ping it?

[Ex Machina]

Of course, ping is ICMP not TCP and thus is not subject to this problem. Oops! But the Voyager web configuration panel won't work!

Re:Can we still ping it?

[HaloZero]

Apologies, my units are off. I did intend to write 29 HOURS. Alas, stupid fingers.

Re:Can we still ping it?

[jafiwam]

I wish that "vger6" guy would stop logging onto the same CS server I am on.

Really throws the game when he gets all choppy and stuff....

Re:Can we still ping it?

[Klintus Fang]

not sure how much data they are getting from it now, but they are tracking it. there is an observed anomaly in its current trajectory that is not well understood. Unfortunately I can't find a good link on it, but the issue is this:

the craft's current rate of acceleration as it heads away from the sun is not consistent with current gravitional laws.

From what I've read, it is considered likely that the issue is just some exotic side effect of the conventional physics inside the space craft itself (like waste heat shedding off the craft's antenna exerting a small force on the craft and altering its trajectory slightly). It's possible though that it is an indication of a hole in our existing understanding of gravity.

Not sure what else the craft might be doing. Probably not much. But that little anomaly is pretty interesting.

Re:Can we still ping it?

[p0tat03]

"Compare that to an MP3, which can be streamed that same distance in only half a day!"

... A record player hooked to a radio transmitter could claim the same thing (given enough broadcast power)

Re:Can we still ping it?

[wiggles]

Heh... You must work for NASA :)

Re:Can we still ping it?

[Anonymous Coward]

ping voyager1

Pinging voyager1 with 32 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

No. At least, I can't.

Re:Can we still ping it?

[div_2n]

To be exact, it would be 50,034.6s = 833m 54.6s = 13h 53m 54.6s . . . one way.

Or, 100,069.2s = 1,667m 49.2s = 27h 47m 49.2s roundtrip . . . assuming a perfect vaccum and no processing time on both ends.

Of course, these calculations are based on static distances and it would require a bit more tweaking to figure out the exact numbers to account for the delta in distance up to this minute and the delta in distance during the sending of a signal.

Re:Can we still ping it?

[mustafap]

Wow, to think that TCP/IP hadn't been invented when it was launched ;o)

Re:Can we still ping it?

[BillEGoat]

Compare that to an MP3, which can be streamed that same distance in only half a day!

Yeah, but the RIAA'd be all up on your arse.

Re:Can we still ping it?

[Java Pimp]

It wants you to key in the last 8 bits of your ip address manually.

Re:Can we still ping it?

[russ1337]

It is because its heading toward a black hole.....but why has no-one seen it? I'll ask Holly. Holly, why has no one noticed that Voyager is heading into a black hole?

Holly: Well, the thing about a black hole - it's main distinguishing feature - is it's black. And the thing about space, the color of space, your basic space color - is it's black. So how are you supposed to see them?

Re:Can we still ping it?

[thebudgie]

And just realising that I need to consider the return time too, making it 1600 minutes. I'm silly sometimes.

Re:Can we still ping it?

[canavan]

Not quite. The supposed anomaly of gravity can be measured with the spin stabilized pioneer 10 and 11 spacecraft, since those practically never have to use their thrusters to adjust their attitude. The voyager spacecraft on the other hand are 3 axis stabilized with hydrazin thrusters, which they have to use every now and then to keep their radio dish pointed at earth. Their useful science comes from the data they gather about magnetic fields, charged particles etc.

Re:Can we still ping it?

[WED Fan]

the craft's current rate of acceleration as it heads away from the sun is not consistent with current gravitional laws.

Could you amend that to read, "is not consistent with our current understanding of gravity" or "is not consistent with our apparently flawed gravitational laws"?

Really, I wish they would stop calling these things "law". Every generation sees a bushel of these "laws" being thrown out, adjusted, or ignored.

The Universe doesn't play by our "laws", it just waits until we understand Its LAWS.

Re:Can we still ping it?

[vnangia]

Are you're confusing it with the Pioneer Anomaly, which occurs on spin-stablized spacecraft? Voyager is three-axis stablized, and not subject to the anomaly.

Re:Can we still ping it?

[Abcd1234]

Umm, if you read the article, you'll note that it's not that the Voyagers aren't subject to the anomaly, it's that it's too difficult to measure, since you'd have to cancel out the effect of the thruster use.

Re:Can we still ping it?

[bean123456789]

If only we had the ansible, then you could have an interstellar frag fest!

Re:Can we still ping it?

[Klintus Fang]

I have seen reference to it as the pioneer anomaly and as the voyager anomaly. What you are saying makes sense though. Has the anomaly not been observed at all on Voyager craft because the need to periodically reorient the dish makes it impossible to know if it is happenning at all? Or is it just that it is too difficult to study with the voyager craft?

Re:Can we still ping it?

[Anonymous Coward]

"Law" has a well-established meaning in science to refer to a mathemtical relationship. It does not mean "uncontestable and immutable fact".

For example, I could say that "g = G * (M1 + M2)" is a law of gravity. It's a hopeless incorrect and thus useless one, of course. Newton's is much better -- though still not perfect. Nonetheless, it's still Newton's Law of Gravity.

Merriam-Webster Online Dictionary

Main Entry: law
Pronunciation: 'lo
Function: noun

3 : a rule of construction or procedure

6 a : a statement of an order or relation of phenomena that so far as is known is invariable under the given conditions b : a general relation proved or assumed to hold between mathematical or logical expressions

Re:Can we still ping it?

[iluvcapra]

Ha ha only serious. The reason you can't buy the golden record as a multimedia CD-ROM (or anything else) is because the music and images on it are under copyright, and the selections were only released to NASA for use by alien audiences only. :p

Re:Can we still ping it?

[XenoRyet]

His use of the word "current" is enough implication that the law might be flawed. However, they can't definitly nail it down to a gravitational effect, so it would be premature to say "apparently flawed," as the law may not be.

Our current understanding of gravity fits the definition of a scientific law, thus there is no need to call it anything else. There is also no problem with these laws occasionaly being changed or thrown out. There is nothing in the definition of a scientific law that says it cannot be thrown out due to new data or understanding. The definition mearly requires that there there have never been repeatable contradictions.

Re:Can we still ping it?

[Tiger4]

Heh... You must work for NASA :)

You insensitive clod! He did to work for NASA, but after the Mars incident he's been unemployed.

Re:Can we still ping it?

[StikyPad]

Wow, to think that TCP/IP hadn't been invented when it was launched... would be wrong.

There, fixed that for you.

Re:Can we still ping it?

[anakin876]

Data from Voyager: ummm, gee, it sure is cold out here. Does anyone have a blanket? I feel so lonely. Daisy, Daisy.....

Re:Can we still ping it?

[Catamaran]

You must also take into account the fact that the signal is travelling slower because the spacecraft is moving away from us.

Re:Can we still ping it?

[Anonymous Coward]

god I hope you're joking

Re:Can we still ping it?

[Killall -9 Bash]

c is always c. the signal will just get red-shifted.

Re:Can we still ping it?

[clem]

V'ger wishes to gib the creator.

Re:Can we still ping it?

[durnurd]

I think that interstellar space is outside the jurisdiction of the Recording Industry Association of America.

Re:Can we still ping it?

[WindBourne]

ah heck. It is all relative.

Re:Can we still ping it?

[Hotawa Hawk-eye]

Yup. Light takes about 8 minutes to reach Earth from the Sun, and Voyager 1 is now out 100 times the distance between the Earth and the Sun, so it's an 800 minute one-way trip, or 1600 minutes round trip.

Re:Can we still ping it?

[idonthack]

And the Pirate Bay was in Sweden.

Re:Can we still ping it?

[Anonymous Coward]

... use their thrusters to adjust their attitude

That's an interesting way to adjust someone's attitude... :)

Re:Can we still ping it?

[PylonHead]

Lister: Holly, what's the problem? You're supposed to have an IQ of 6000, aren't you?
Holly: Look, we're travelling faster than the speed of light. That means, by the time we see something, we've already passed through it. Even with an IQ of 6000, it's still brown trousers time.

Re:Can we still ping it?

[Ex Machina]

"last" 8 bits seems a little redundant for 1977!

<link> is an 8 bit link number

Re:Can we still ping it?

[Large Green Mallard]

That must be why my printer is the size of a small car and has a golden record attached to it..

Re:Can we still ping it?

[Anonymous Coward]

No, not 29 minutes. Think hard. We are (approximately) 93 million miles from our sun. If voyager 1 is 100 AU from us, then its (roughly) 100 AU from the sun. Light is electromagnetic radiation. It travels at 186283 miles per second (light from the sun takes 93000000/186283 seconds to reach us). Since light takes 8 minutes, 19.24 seconds to reach us at 1 AU, then a source 100 AU away takes 13 hours 52 minutes 4 seconds to reach us (100 times as long as 8 minutes, 19.24 secons). A ping request is sent (possibly) as a two-tone response, but in any event, its an electromagnetic radition wave (a radio wave), just like light, and travels at the same speed. So it takes nearly 14 hours for a sent ping to be recieved, and 14 more hours for the reply pong to be recieved back. 28 hours for bidirectional communication. Kewel!

Re:Can we still ping it?

[Anonymous Coward]

NASA's grammar and spelling is horrible. They don't even know what "prospective" means. Christ. It's no wonder they can't convert to metric properly.

Re:Can we still ping it?

[Compuser]

Your page says that the IP part of TCP/IP emerged in 1978 and was finalized around
1980, whereas Voyager 1 was launched in 1977. So at least technically the OP is right.

Re:Can we still ping it?

[jackbird]

"throughout the universe" is a clause commonly seen in documents assigning or asserting copyrights.

Re:Can we still ping it?

[Schraegstrichpunkt]

Of course, ping is ICMP not TCP and thus is not subject to this problem.

Actually, the IPv4 packet will expire long before the maximum TCP RTT comes into effect. From RFC 791, section 3.1; page 14 (with emphasis added):

Time to Live: 8 bits

This field indicates the maximum time the datagram is allowed to remain in the internet system. If this field contains the value zero, then the datagram must be destroyed. This field is modified in internet header processing. The time is measured in units of seconds, but since every module that processes a datagram must decrease the TTL by at least one even if it process the datagram in less than a second, the TTL must be thought of only as an upper bound on the time a datagram may exist. The intention is to cause undeliverable datagrams to be discarded, and to bound the maximum datagram lifetime.

So, the maximum lifetime for an IPv4 packet is 255 seconds. That gives you a 510-second maximum ping time for IPv4.

IPv6 changed the field to be a pure "hop count", so perhaps you'll be able to use it to ping Voyager 1.

Re:Can we still ping it?

[RedDevilCG]

Are you thinking about the Pioneer Space Probes? Here is a link to an article on the BBC that I think you might be thinking of: http://news.bbc.co.uk/1/hi/sci/tech/1332368.stm

Re:Can we still ping it?

[Anonymous Coward]

Doesn't seem like TTL would be a problem since the latency is due to the transport between the routers, not processing in the routers themselves. That is, there's nothing in its 27+ hour journey that would actually decrement the TTL (or indeed even be able to). The RFC doesn't give any indication that a router needs to anticipate how long the next hop will take to decrement the TTL as it just refers to processing time.

Re:Can we still ping it?

[Duds]

In space, no-one can hear you sue.

Re:Can we still ping it?

[Schraegstrichpunkt]

The RFC doesn't give any indication that a router needs to anticipate how long the next hop will take to decrement the TTL as it just refers to processing time.

Actually, it does. In several places. Search for "time to live" (case insensitive) in the RFC. You'll find that it is quite clear that the TTL is intended to be the maximum total datagram lifetime, so obviously a router will have to account for transmission delays.

For example, see page 30 (emphasis mine):

Time to Live

The time to live is set by the sender to the maximum time the datagram is allowed to be in the internet system. If the datagram is in the internet system longer than the time to live, then the datagram must be destroyed.

This field must be decreased at each point that the internet header is processed to reflect the time spent processing the datagram. Even if no local information is available on the time actually spent, the field must be decremented by 1. The time is measured in units of seconds (i.e. the value 1 means one second). Thus, the maximum time to live is 255 seconds or 4.25 minutes. Since every module that processes a datagram must decrease the TTL by at least one even if it process the datagram in less than a second, the TTL must be thought of only as an upper bound on the time a datagram may exist. The intention is to cause undeliverable datagrams to be discarded, and to bound the maximum datagram lifetime.

Some higher level reliable connection protocols are based on assumptions that old duplicate datagrams will not arrive after a certain time elapses. The TTL is a way for such protocols to have an assurance that their assumption is met.

On page 27, it discusses fragment reassembly:

...
If this is the first fragment (that is the fragment offset is zero) this header is placed in the header buffer. If this is the last fragment ( that is the more fragments field is zero) the total data length is computed. If this fragment completes the datagram (tested by checking the bits set in the fragment block table), then the datagram is sent to the next step in datagram processing; otherwise the timer is set to the maximum of the current timer value and the value of the time to live field from this fragment; and the reassembly routine gives up control.
...

And the glossary defines the TTL quite succinctly (page 43):

Time to Live

An internet header field which indicates the upper bound on how long this internet datagram may exist.

The only thing I've found that contradicts my position is this (again from page 30):

This field must be decreased at each point that the internet header is processed to reflect the time spent processing the datagram.

However, this is not exclusive, i.e. it doesn't say that the field must only be decreased to reflect the processing time, and interpreting it as being exclusive would contradict the other sections that I have quoted.

There is a reason why acronyms like "IIRC" and "AFAIK" exist. If you can't be bothered to research things (which is understandable; this is Slashdot, after all) then you should at least have the honesty to use those acronyms.

Re:Can we still ping it?

[Anonymous Coward]

Anyone's got its IP address?

Re:Can we still ping it?

[Anonymous Coward]

Yeah, but if you use a Bigfoot Killer NIC you can offload the TCP/IP processing and cut the response time to milliseconds...

Re:Can we still ping it?

[Opportunist]

Sounds like my university server close to mid-term deadlines...

Re:Can we still ping it?

[LordVader717]

Hehe, stupid div. *giggle* Special relativity *giggle*

Re:Can we still ping it?

[dotgain]

I don't think NASA would care much what the round trip time was. It's not like they're going to ssh into it or anything.

Re:Can we still ping it?

[div_2n]

Perhaps you can elaborate on what you _think_ special relativity has to do with what I said. Since our velocity on Earth and that of the Voyager are not changing much, the frame of reference to c remains unchanged during the lifetime of the measurement. Thus, the unit of measure time remains constant for the purpose of this measurement with regards to our frame of reference.

So, by all means, please elaborate on how you think special relativity fits in the picture.

Re:Can we still ping it?

[KDR_11k]

Which is why the IFPI was filing the lawsuits, not the RIAA.

Re:Can we still ping it?

[Ana10g]

what happens when you redshift packet data anyway? (not that I'm implying I think voyager runs on a packet-based protocol, I actually have no idea:)

Re:Can we still ping it?

[pilsner.urquell]

100 Astronomical Units = 831.675359 light minutes

light minutes are a measurement of distance the same as a light year the distance light travels in one minute. However, a radio single travels 1 AU in in approximate 8 minutes and I can do the math in my head. Travel time, one way, is 13h 20m at 100 AU

Re:Can we still ping it?

[KDR_11k]

Pfft, just sue the universe.

Re:Can we still ping it?

[Ex Machina]

831.675359 / 60 = 13.861256

Re:Can we still ping it?

[Anonymous Coward]

Due to the use of the thrusters, any acceleration that could be due to the pioneer anomaly is buried in the noise and essentially unmeasurable with the voyager spacecraft. This is mentioned e.g. here or here.

Re:Can we still ping it?

[Majestix]

And you work for the public school system Mr. "did to work". ;)

Re:Can we still ping it?

[Cally]

google 'Voyager mystery force site:slashdot.org' :)

Re:Can we still ping it?

[Mycroft_VIII]

Actually nothing you cite says the sender has to be aware of or compensate for speed-of-light delays of this magnitude. At best it implies the recieving unit is responsible for correcting the ttl field, and even then only requires a decrement of one in the case where the reciever does not know the elapsed time to 'process' the datagram.
      IP was designed with terrestrial (and perhaps orbital satalite) networks in mind and doesn't adress the issue or even aknowledge it.

Mycroft

Re:Can we still ping it?

[Schraegstrichpunkt]

Actually nothing you cite says the sender has to be aware of or compensate for speed-of-light delays of this magnitude.

The text I've cited states that the TTL specifies the maximum lifetime, in seconds, of a datagram. If your part of the network causes packets to live longer than their TTL, by whatever means, then you're violating the RFC. I'm not sure how much clearer I can make it.

In any case, it's largely irrelevant, since---as you said---IP was designed for terrestrial networks.

Re:Can we still ping it?

[Anonymous Coward]

It also indicates that previously IP was part of TCP, so technically the OP is wrong. If I recall correctly (not that I was there) aside from technical reasons, the separation was introduced to give an appearance of OSI compatibility.

Re:Can we still ping it?

[Mycroft_VIII]

Because it's the job of the sender to indicate Desired TTL, it's the job of each hop along the route to try and 'enforce' this.
    re-read what was cited, it's pretty clear that the originator has no burden to determine how long it'll take to reach and be processed at each stop. Notice who's responsible for decrementing the ttl and who's responsible for discarding packets when thier ttl drops to 0.
    Suppose I send out something with a ttl of 5, and along the way it goes through a few not-so well configured routers and gets bounced off of goe-sync sats a dozen times. By you're reasoning my process should never have sent the packet in the first place because it should have known it'd take to long even though no mechanism exists for it to know.
    It really only makes sense that transit time is NOT part of the protocal (as not really thought about when writing it, thus the confusion the use of seconds often causes). Note that it never mentions signal time but refers to processing time. TTL is max # hops/operations on packet, or total time being actually handled or held by a process as measured in seconds(if known) with max value off 255.
    TCP IIRC doese however provide mechanisms that reflect round trip time limits.
There has been discussion about what happens to the internet when we need to it to reach off planet (Moon/Mars). IP's issue was mostly address space (though newer versions of IP have MUCH bigger address spaces) IIRC, and TCP was the one with lag issues.
    I'd have to dig for the details, but I've been up 21 hours on 6 hours sleep so that'll have to wait.

Mycroft

Re:Can we still ping it?

[Schraegstrichpunkt]

Suppose I send out something with a ttl of 5, and along the way it goes through a few not-so well configured routers and gets bounced off of goe-sync sats a dozen times. By you're reasoning my process should never have sent the packet in the first place because it should have known it'd take to long even though no mechanism exists for it to know.

No, that would be ridiculous. What I'm saying is that those "not-so well configured routers" are each supposed to decrement the TTL by some value greater than the actual number of seconds a transmission will take. It's fairly easy to do on a hob-by-hob basis; Anybody who doesn't know that their router is directly connected to a satellite uplink shouldn't be allowed near an Internet router anyway. It complicates the design of routers somewhat, but IPv4 has always assumed moderately complex routers, at least when compared with IPv6.

It really only makes sense that transit time is NOT part of the protocal (as not really thought about when writing it, thus the confusion the use of seconds often causes). Note that it never mentions signal time but refers to processing time. TTL is max # hops/operations on packet, or total time being actually handled or held by a process as measured in seconds(if known) with max value off 255.

That's probably a sensible way to look at it, but it's not what the spec says. Your interpretation limits the TTL to just "processing time" or a "hop count", which contradicts the RFC 791 definition of TTL:

Time to Live

An internet header field which indicates the upper bound on how long this internet datagram may exist.

My position has never been that it was a good idea to treat the TTL as anything other than a hop count (and in fact IPv6 has replaced the TTL with a simple hop count). I simply state that RFC 791, as it stands, requires that routers decrement the IPv4 TTL by no less than the number of seconds that a packet will take to arrive at the next hop.

You posted:

There has been discussion about what happens to the internet when we need to it to reach off planet (Moon/Mars). IP's issue was mostly address space (though newer versions of IP have MUCH bigger address spaces) IIRC, and TCP was the one with lag issues.

Indeed. TCP/IP was designed under the assumption that bits are cheap, roundtrips are short, and processing time is relatively expensive. Interplanetary data links are just the opposite, so we're never going to have FTP to Mars or to Jupiter (though we might have email, but probably not over SMTP or any TCP-based protocol).

Re:Can we still ping it?

[Mycroft_VIII]

There is NO requirement to 'guess' how long any part of the trasit will take and pre-emptive decrementing of ttl to do so would be contrary to 791.
    While the part you quote shows the untis TTL is measured in and why, HOW and when those units are measured explained pretty much how I described them.
From RFC 791:

        This field must be decreased at each point that the internet header
is processed to reflect the time spent processing the datagram.
Even if no local information is available on the time actually
spent, the field must be decremented by 1. The time is measured in
units of seconds (i.e. the value 1 means one second). Thus, the
maximum time to live is 255 seconds or 4.25 minutes. Since every
module that processes a datagram must decrease the TTL by at least
one even if it process the datagram in less than a second, the TTL
must be thought of only as an upper bound on the time a datagram may
exist. The intention is to cause undeliverable datagrams to be
discarded, and to bound the maximum datagram lifetime.

emphasis mine

    Any sender decrementing ttl based on what happens AFTER the datagram leaves
it is acting outside the rfc, if any party were to decrement the ttl based on
transit time it would make more sense for the reciever to do so, but again this
would outside the stated rules for ttl in rfc 791. Though I haven't read any
explicit prohibitions against reducing the ttl more than required, it does seem
implied by the wording to me (in terrestrial networks it could cause excessive
datagram loss and would be pointless elswise).

  The rfc makes it pretty clear it's processing time and NOT transit time
that is the main concern. Considering that it was written at a time when
processing power was at a premium and the intended target of the protocal
was terrestrial communications systems considerations for transit time were
minimal, though the protocal does allow for timestamping of the datagrams.

Mycroft

lol, wut

[voice_of_all_reason]

Scientists still hope it will find the edge of the solar system and get into interstellar space.

What else could it possibly "find"?

Re:lol, wut

[jbrader]

That's the whole point of course.

Re:lol, wut

[VorpalEdge]

The question is whether or not Voyager will still be functioning when it does. :/

Re:lol, wut

[pixelpusher220]

it doesn't need to be functioning...that's why the Gold Record with info on it was included as part of the mission ;-)

Re:lol, wut

[Anonymous Coward]

Most likely a sign: Keep out, unstable life forms beyond this point!

Re:lol, wut

[drinkypoo]

out of curiosity, where is the record stored? in pictures it always looks like it's attached to the outside of the craft but my understanding is that it's in an aluminum box with a needle. where is it actually installed into the thing?

Re:lol, wut

[voice_of_all_reason]

"Galaxy closed due to AIDS?"

Re:lol, wut

[eqisow]

It could always crash into Planet X.

Re:lol, wut

[Anonymous Coward]

Scientists still hope it will find the edge of the solar system and get into interstellar space.

What else could it possibly "find"?

The question is: How can it miss??

It's not like the edge of the solar system is a door floating in the vast amounts of space
saying
 
Welcome to the rest of the universe. To assure a smooth transition please answer these questions truthfully:

1.Are you now or have you ever been a member of the Communist Party?
2.Have you ever been affiliated or associated with the Nazi Party?
3.Have you ever deserted from the military, air or naval forces?
4.Have you ever failed to file a federal income tax return?
5.Do you pay taxes?
6.Have you ever been a habitual drunkard?
7.Have you ever been a prostitute?
8.Have you ever advocated or practiced polygamy?
9.Have you ever been an illicit trafficker in narcotic drugs or marijuana?

Re:lol, wut

[godless dave]

There's the chance it could find nothing if it poops out before it reaches the edge, since they don't know where the edge is.

Re:lol, wut

[Shadowmist]

It can give us some actual environmental data on the conditions of interstellar space. What will happen once Voyager gets to the point where solar wind and magnetism finally gives way to the interstellar medium.

Lesson 102: Space is not simply an empty vacum. It's an environment of it's own with lots of forces that can come into play. Gravity, magnetic fields, solar and cosmic radiation. For all we know we might find the spacecraft picking up a slight electrical charge which could alter it's course the same way that CRTs work.

Remember "The Truman Show"?

[Anonymous Coward]

Yeah.

Voyager 1

[thatguywhoiam]

.. has to be one of the best things we (humankind) have ever made. Just in terms of sheer engineering prowess.

If you are like me and love reading about Voyager 1 stuff, here's a great blog post with tons of linked info on the Golden Record, the philosophy behind the probe, who worked on it, that sort of thing.

Amazing

[colonslashslash]

As the article points out, it is pretty amazing that this vehicle has travelled so far... 9.3 billion miles is an insane distance alone, but through the hazards of space - 30 years of asteroids, comets, uber death wave radiation and Borg, it's even more astonishing.

Kudos JPL.

Re:Amazing

[tool462]

The irony being that it was meant to land on Mars, but they got the units wrong then too. *duck*

Re:Amazing

[zimus]

... 9.3 billion miles is an insane distance alone ...

I dunno, that's still too close to the in-laws for my taste.

gee, thanks slashcode

[thatguywhoiam]

... for rendering my post useless. sheesh. Here is the link it ate:
http://g-fav.blogspot.com/2006/07/hey-linguists-an d-ethnomusicologists.html

(and now I must wait 49 seconds to amend it, ferfuxsake. slowdowncowboyslowdowncowboyslowdowncowboy)

Not bad!

[Anonymous Coward]

Not bad for "faster, smarter, cheaper".... Oh wait, that was put up there 30 years ago by the OLD NASA.

um...

[XanC]

While your post was nice, I wouldn't describe it as a "great blog post". Or did you miss a link? :-)

V'ger 1 and Amateur DSN

[John Miles]

This is a good place to mention Luis Cupido's web site. He's actually managed to pick up the Voyager 1 signal on a 5.6-meter dish, using a lot of DSP-fu and maybe -- you be the judge -- a bit of wishful thinking.

A fascinating, if somewhat slow-loading, page.

Re:V'ger 1 and Amateur DSN

[casings]

A fascinating, if somewhat slow-loading, page

Fascinating that he was able to use Voyager 1 to host his site...

Re:V'ger 1 and Amateur DSN

[Pharmboy]

Fascinating that he was able to use Voyager 1 to host his site...

That would explain the 30 year ping times.

Re:V'ger 1 and Amateur DSN

[Amazing Quantum Man]

Except that since it's 100AU, and an AU is approximately 8 light-minutes, a roundtrip ping time would be 1600 minutes, or 26 hours 40 minutes.

Now, granted, a 1 day ping time is slow, but it's not a 30 year ping time!

Batteries not included......

[SQLGuru]

The Voyagers owe their longevity to their nuclear power sources, called radioisotope thermoelectric generators, provided by the Department of Energy

30 years without changing the batteries *AND* 30 years without exploding. Can I get one of those?

Layne

Re:Batteries not included......

[nule.org]

More importantly, can Dell get 4.1 million of these? And kind of quickly?

Re:Batteries not included......

[E IS mC(Square)]

One thing I now know about Voyager 1 is that those batteries were not sourced from Sony!

Re:Batteries not included......

[Klintus Fang]

30 years without changing the batteries *AND* 30 years without exploding. Can I get one of those?

i know little about the specs of those generators, but somehow I suspect that you wouldn't find the current they are able to provide satisfactory... :-b

Re:Batteries not included......

[badasscat]

More importantly, can Dell get 4.1 million of these? And kind of quickly?

I'm not sure you want to have a nuclear energy source sitting on your lap for very long. Not good for the missus, if you know what I mean.

Re:Batteries not included......

[Anonymous Coward]

30 years without changing the batteries *AND* 30 years without exploding. Can I get one of those?

Considering the problems associated with handing plutonium (that's in those things) to the masses, I guess the answer will be 'no'.

Re:Batteries not included......

[jthill]

You'll be surprised, then. It started out at 420W. Pu238 halflife is ~90 years: I think it'll still melt your Dell, if you want to put ~120Kg of power supply into it.

Re:Batteries not included......

[drinkypoo]

Well, I'm sure I do, so long as it just makes me sterile, and doesn't cause cancer. I think a hottub is the interim solution, roasted nuts don't work as seed.

Re:Batteries not included......

[yobjob]

One thing I now know about Voyager 1 is that those batteries were not sourced from Sony!

Yes they were - that's the propulsion mechanism.

Re:Batteries not included......

[AaronHorrocks]

Due to slowly decaying nuclear materials for a powersouce, the Voyager power supply has been producing less and less power over the years. One of the things the crew has had to do is turn systems off over time to keep the probe functioning.

Re:Batteries not included......

[rethin]

'm not sure you want to have a nuclear energy source sitting on your lap for very long. Not good for the missus, if you know what I mean.

I read Slashdot. So no, I don't know what you mean.

Re:Batteries not included......

[jesterpilot]

You can get them in India, in a place called Nanda Devi. http://www.deccanherald.com/deccanherald/apr252004 /fp2.asp

Re:Batteries not included......

[SQLGuru]

As a follow up, I came across this article (May 2005) the other day:

http://www.livescience.com/technology/050513_new_b attery.html

Layne

Well, yes.

[ackthpt]

Scientists still hope it will find the edge of the solar system and get into interstellar space."

The alternative is for the Sun to pull it back.

To sail on a dream through eternal nighttime of space To ride on the crest of a wild raging storm To work in the service of life and the living In search of the answers to questions unknown To be part of the movement and part of the growing Part of beginning to understand

Aye, Voyager, the places you've been to The things that you've shown us The stories you tell Aye, Voyager, I sing to your spirit The men who have served you So long and so well

a tip of the prop to the late John Denver

Re:Well, yes.

[Anonymous Coward]

a tip of the prop to the late John Denver

Your C & D is in the mail -RIAA Shark

Re:Well, yes.

[shadowbearer]

"wild raging storm" -- "wild particle storm" ? :-)

  Well, I liked it, anyway. But I've always loved JD's Calypso.

  In another way of looking at it, Voyager is headed out in the Black...

SB

Re:Well, yes.

[SamSim]

The alternative is for the Sun to pull it back.

Voyager is moving fast enough that that will never happen. It will escape the Solar System entirely. In some senses it already has. The real question is how long until it stops transmitting, and how long until it gets hit by a random chunk of space rock (the latter event probably coming MUCH later than the former).

Interstellar 3.0

[Anonymous Coward]

The point is, the two Voyagers are the last of the first generation of robotic interstellar spacecraft. Interstellar 2.0 will use ion drive, nuclear electric, solar sails, magnetic sails, and other exotic propulsion technologies. Interstellar 3.0 will get useful paylods to other planetary systems, within the lifetime of some slashdot readers. Cost? Less than the Shuttle/Space Station welfare system. Payoff? Priceless! Starflight without Warp Drive Hydrogen Ice Spacecraft for Robotic Interstellar Flight

Re:Interstellar 3.0

[Anonymous Coward]

Interstellar 2.0 will use ion drive, nuclear electric, solar sails, magnetic sails, and other exotic propulsion technologies.

I bet Voyager will be pissed when one of these newfangled probes sails past it, but just to make sure we should program it to broadcast "HA! HA!" at CPA.

Re:Interstellar 3.0

[SamSim]

Yes, and by 1990 scientists predict we'll have four colonies on the Moon, ideal for family vacations.

Forgive my pessimism. I believe landing on the Moon is the greatest thing humans have ever done, and that the Voyager and Pioneer probes represent the peak technological achievement of our species. I believe space exploration is the most important thing ever. I am desperate for these new technologies to take us off this rock. But seriously, how long will we have to wait? A hundred years? Two hundred? At the current rate of progress these seem like low estimates indeed. Pick any hard science fiction book with a fictional future timeline and just look at the milestones which should have been and gone by now. Will we really be mining asteroids by 2500? Looking at the state of play on Earth right now, it's hard to keep believing.

Radioisotope Thermoelectric Generators

[Lazbien]

The article states that Voyager 1 is using radioisotope thermoelectric generators to power the flight... not knowing what these were, I went to Wikipedia, which told me that they were used to generate a few hundred watts or less, and seem to get hot. My question from this is the application in to on-Earth areas. For instance, why aren't radioisotope thermoelectric generators used in Data Centers? Or Factories? Or Office Towers? Or on farms? Can't we take a few hundred of these, bury them in a sub-basement, and start generating our own power? I want my space age power, damnit. Any rocket scientists out there know the cost of one of these suckers?

Re:Radioisotope Thermoelectric Generators

[Feyr]

reasons..

1) cost
2) insulation (from radiation/heat)
and chiefly 3) NIMBY crowd and ecolo-weenies

Re:Radioisotope Thermoelectric Generators

[russ1337]

generate a few hundred watts or less, and seem to get hot

they use them in Macbooks and Dell computers - and a whole bunch of them just go recalled.

Re:Radioisotope Thermoelectric Generators

[TooMuchToDo]

From the very same Wikipedia article:

http://en.wikipedia.org/wiki/Radioisotope_thermoel ectric_generator#Efficiency

"Thermocouples, though very reliable and long-lasting, are very inefficient; efficiencies above 10% have never been achieved and most RTGs have efficiencies between 3-7%."

So to answer your question, they're made to make a little power for the spacecraft to survive millions of miles from potential energy sources, but would be horribly ineffiencient to be used to generate power on Earth (when we have more efficient ways to do it).

Re:Radioisotope Thermoelectric Generators

[sickofthisshit]

These RTG generators are compact, robust, and long-lived. However, they are not cheap, do not deliver huge quantities of power, decay slowly over time, do not respond to peak load requirements, and are not really efficient. (They use raw heat from radioactive decay, and thermoelectric conversion.)

On Earth, we can pile up a large amount of radioactive material to cause a controlled chain reaction. We can then convert it on an industrial scale to AC electric power for distribution over many miles. You may have seen something called an "electric outlet", where you can pay pennies for a kilowatt hour? And lead-acid batteries to tide you over if the electric grid goes out?

Re:Radioisotope Thermoelectric Generators

[Anonymous Coward]

Unfortunately, it's hard enough for NASA to use RTGs without the enviro-kooks storming their gates with pitchforks and torches. At this point, privately-owned RTG power sources don't sound likely, due to the potential for accidental or intentional misuse.

Re:Radioisotope Thermoelectric Generators

[LWATCDR]

Umm... Read more fellow. They use Plutonium... They are radioactive and could be used to make at least a dirty bomb if not an outright fission device.
They uses some in the old Soviet Union at some remote sites but they used Strontium 90 which while it will still kill you can not be used to make fission devices.

Not something I would want in my basment but dang handy in space and maybe some remote applications like ocean monitoring or even antarctica.

Re:Radioisotope Thermoelectric Generators

[man_ls]

The heat source is decaying radioactive waste, typically not something you want around people. They put them on spacecrafts because there's little danger of someone else getting hit by the radiation as the device operates. Putting them on the Earth would require extensive shielding, and turn every data center into a potential terrorist dirty bomb target.

Re:Radioisotope Thermoelectric Generators

[MoFoQ]

well...the "Fear" of anything nuclear (it's funny how all those environmentalists bitch and moan about a few kilograms of uranium when many tons of it was released into the atmosphere due to coal power plants (ref: http://www.ornl.gov/info/ornlreview/rev26-34/text/ colmain.html)

By the year 2040, the prediction/projected cumulative amounts released by coal burning plants is
U.S. release (from combustion of 111,716 million tons):
Uranium: 145,230 tons (containing 1031 tons of uranium-235)
Thorium: 357,491 tons

Worldwide release (from combustion of 637,409 million tons):
Uranium: 828,632 tons (containing 5883 tons of uranium-235)
Thorium: 2,039,709 tons

Anyways, back to the subject at hand, why can't we make the radioisotopes now in nuclear waste facilities (especially in the Yucca Mountain range in Nevada) produce energy using a RTG? It may not be the most efficient method but the stuff is just "sitting" there and can't be used in a traditional power generation method.

Just a thought. It might at least be able to power the lighting systems at those facilities.

Re:Radioisotope Thermoelectric Generators

[Vellmont]

They are radioactive and could be used to make at least a dirty bomb if not an outright fission device.

It would probbably make a very good dirty bomb, but Pu-238 is a lousy choice for a fission bomb. The reason is that it has a high rate of spontaneous fission (and emits neutrons in the process). This would cause the plutonium to undergow premature detonation before the mass of Pu was compressed. The result would be a much smaller explosion.

Re:Radioisotope Thermoelectric Generators

[Waffle Iron]

well...the "Fear" of anything nuclear (it's funny how all those environmentalists bitch and moan about a few kilograms of uranium when many tons of it was released into the atmosphere due to coal power plants

You've just shown that you have no understanding of this issue. For example: your 145,000 tons of uranium is an isotope with a half-life of about 4 billion years. (The small amount of U235 has a half life of 700 million years, and doesn't change the overall total much.) Thorium is similar: it has a half-life of 14 billion years.

An RTG is filled with plutonium 238, which has a half life of 88 years, so it decays about 49 million times as fast as U238. So the total radioactivity of all that coal-based uranium is similar to that of 3 kilograms of Pu238, which is only enough fuel to provide a few kilowatts of RTG power. So it's no wonder environmentalists bitch and moan about a few kilograms of material: that few kilograms is about as radioactive as the total annual emissions of the entire coal industry.

So bottom line, to provide their electrical energy from RTGs, each household would need to manage an amount of radioactivity which is a significant fraction of the grand total emitted by all US coal burning plants. Coal plant heavy metal emissions are dangerous, but mainly because heavy metals are toxic chemicals, not because of radioactivity.

A more practical problem is the fact that Pu238 is outrageously hard to collect and there are only a few kilograms in existence worldwide. Other kinds of radioactive waste isn't generally hot enough to create a useful amount of work; otherwise, they would have left it in the reactor longer to generate more power.

Re:Radioisotope Thermoelectric Generators

[Amouth]

the thing is it can be used in reactors .. jsut not the normal.. breader reactors or pebbel reactors will work with it

Re:Radioisotope Thermoelectric Generators

[meringuoid]

Umm... Read more fellow. They use Plutonium... Not something I would want in my basment

Hell, I would. RTGs are inefficient at generating electricity maybe, but I reckon they'd make a fine nuclear water heater. Free hot water, no more central heating bills.

I just wouldn't feel comfortable with you having it in your basement. Dirty bombs, as you say. Nasty.

Re:Radioisotope Thermoelectric Generators

[ch-chuck]

Hot notebooks just make you sterile - RTG laptops make your children mutants.

Re:Radioisotope Thermoelectric Generators

[Firethorn]

You've just shown that you have no understanding of this issue. For example: your 145,000 tons of uranium is an isotope with a half-life of about 4 billion years. (The small amount of U235 has a half life of 700 million years, and doesn't change the overall total much.) Thorium is similar: it has a half-life of 14 billion years.

I'd suggest reading his post a bit better, he changed topics to talking about nuclear waste, which tends to be very hot indeed.

But let's do the math

It's not the best source, but This document seems to think that 4-13 watts/kilogram is the range for a spent fuel assembly in it's first year outside the reactor. Rods seem to run 320-658kg. at 13 watts/kilogram, 1 heavy rod will run ~8.5 kilowatts. At 5% efficiency, as mentioned elsewhere on the thread, we're back down to 427 watts. That would result in 3.7 kw/hours of electricity a year, worth ~$.45 at retail electricity rates. Probably not worth it. ;)

For the math freaks: I rounded my posts, not the calcs.

Re:Radioisotope Thermoelectric Generators

[hedwards]

well...the "Fear" of anything nuclear (it's funny how all those environmentalists bitch and moan about a few kilograms of uranium when many tons of it was released into the atmosphere due to coal power plants

Hmm, you don't remember all of the protesting about coal power plants to begin with? It isn't really a matter of a couple of kilograms, it is more to do with the several tons of material required for a plant to run that is a problem.

I also haven't heard many complaints about radioactive bananas; but many about the working conditions of those involved with growing them.

Re:Radioisotope Thermoelectric Generators

[LWATCDR]

Just how big of yield do you need to make it a worth while terrorist weapon?

Re:Radioisotope Thermoelectric Generators

[BigFootApe]

Other kinds of radioactive waste isn't generally hot enough to create a useful amount of work; otherwise, they would have left it in the reactor longer to generate more power.

Sorry. Try again.

Spent fuel is removed because many of the byproducts of fission tend to poison the chain reaction. As the concentration of these contaminants increases in the fuel channels, the reactor loses efficiency. Old fuel bundles must be replaced in order for the reactor to get back up on plane.

There's still a large amount of enriched uranium in the spent fuel, but the used rods must be reprocessed to reclaim it. Also, Plutonium can be recovered from the spent fuel and processed into new fuel (or bombs). Reprocessing spent fuel is controversial because of the expense involved, as well as implications vis-a-vis nuclear proliferation.

Many products of nuclear fission (present in spent fuel) have very short half-lives and generate much heat due to decay. When the spent rods are removed from the reactor, they must be submerged in huge pools of water until they've cooled enough to be worked with. They used rods still have lots of energy in terms of decay. The reactors simply don't generate electricity in the same manner as RTGs, so they can't take advantage of that energy.

Re:Radioisotope Thermoelectric Generators

[Waffle Iron]

Well, to be precise I assumed that if the spent fuel had economically useable amounts of heat, they would presumably shuffle them off to a part of the system where fission isn't going on. Maybe it would be used to preheat the incoming water. However, they don't actually produce enough heat energy to make this worth while, so they just stack them in pools.

Re:Radioisotope Thermoelectric Generators

[savage_panda]

the "batteries" work so well in space due to the temperature difference of close to absolute zero and the tempreature generated by nuclear fission. On earth, you don't get that huge of a temperature gap, so you wont get as much energy from the same amount of fission.

Re:Radioisotope Thermoelectric Generators

[dargaud]

There used to be some in Antarctica, used to power Automated Weather Stations and the like, but they've been banned by the Antarctic Treaty (_no radioactive device allowed_) and replaced by big (1 cubic meter batteries and solar panels + wind generators to last the long winter night). Yup, I work there.

Re:Radioisotope Thermoelectric Generators

[Schraegstrichpunkt]

But how young is too young to allow your children to use RTG-powered cellphones?

Re:Radioisotope Thermoelectric Generators

[Schraegstrichpunkt]

Just how big of yield do you need to make it a worth while terrorist weapon?

Bigger than the alternatives that are just as easy if not easier to acquire.

Re:Radioisotope Thermoelectric Generators

[Schraegstrichpunkt]

There used to be some in Antarctica . . . Yup, I work there.

Very awesome! Are you working there now?

Re:Radioisotope Thermoelectric Generators

[ArtStone]

Little chance of getting hit by the radiation - unless it is the living entity removing that golden record to play it.

Oops! Sorry about that.

(has NASA looked for the missing Apollo 11 tapes on Voyager 1 yet?)

Re:Radioisotope Thermoelectric Generators

[Cyberax]

RTGs were used in autonomous lighthouses and beacons in Russia. The core of a such RTG is a small cyllinder of radioactive material which is heated to 300-400C by radioactive decay.

There's only a small problem: you will get a fatal exposure after two or three minutes near such RTG.

Re:Radioisotope Thermoelectric Generators

[Anonymous Coward]

So it's no wonder environmentalists bitch and moan about a few kilograms of material: that few kilograms is about as radioactive as the total annual emissions of the entire coal industry.

Or, at least, as radioactive as the entire coal industry's annual emissions of uranium. I'm pretty sure that radon is a more significant part of the coal industry's radioactive emissions - it's far more common than uranium, and with a much shorter half-life.

Re:Radioisotope Thermoelectric Generators

[raduf]

      Plutonium is poisonous as hell. Strontium looks a lot like calcium and has a very bad habit of replacing it in living bone tissue... while beeing radioactive. None are things i'd like within 100 miles of where i live. But damn useful in space...

Re:Radioisotope Thermoelectric Generators

[dodobh]

Well, we call them nuclear power plants. Or as the US president puts it, nukluar

Re:Radioisotope Thermoelectric Generators

[phaggood]

Other kinds of radioactive waste isn't generally hot enough to create a useful amount of work; otherwise, they would have left it in the reactor longer to generate more power.

Does it have to be radioactivly-generated heat? I hear the planet's core is a bit on the warmish side.

Re:Radioisotope Thermoelectric Generators

[M1FCJ]

Russians also used them in lighthouses - searching it in Google came up with the news that they are replacing them.

Some years ago there was an investigative journalist piece on BBC TV and they tracked down a couple - apparently Russians can't (or won't) tell exactly how many of these were installed, how many still have nuclear cores and where did the cores go. The journalist mentioned one incident where the nuclear core was nicked and used as a heating source by some local fishermen.

Re:Radioisotope Thermoelectric Generators

[Vellmont]

Just how big of yield do you need to make it a worth while terrorist weapon?

Well, a lot larger than the blast you'd get if your mass of plutonium were just a conventional explosive. I don't know the yield of such a crappy "nuclear" weapon, but I doubt it'd be very much. You'd be much smarter to just use conventional explosives than a Pu-238 bomb.

Re:Radioisotope Thermoelectric Generators

[Anonymous Coward]

A more practical problem is the fact that Pu238 is outrageously hard to collect

Not really; you can breed it easily using a checkerboard pile (like in CANDU, RBMK, the original Ruslan, or the present Lydmilla) with the usual nitration process for extractiing the plutonium. All of the 238Pu for U.S. space probes to date (about 17kg) was bought from Russia.

The 237Np process is too expensive in practice when starting with light water reactor waste products; the 239Pu/americium process is cheaper in Russia, although they have stopped producing 238Pu. Canada could certainly do it the way Seaborg did; they are drowning in deuterated water and the CANDU online checkerboarding would let them do 238U+2H->238NP+2n, 238Np->238Pu+b-.

INL/ATR is the only DOE reactor that can undertake significant 238Pu production. The political headaches associated with breeding 238Pu at Chalk River, and Russia's preference for 90Sr practically eliminating domestic demand for 238Pu, pretty much guarantee that INL will gear up for the neptunium process anyway.

Re:Radioisotope Thermoelectric Generators

[Anonymous Coward]

Well, to be precise I assumed that if the spent fuel had economically useable amounts of heat, they would presumably shuffle them off to a part of the system where fission isn't going on. Maybe it would be used to preheat the incoming water. However, they don't actually produce enough heat energy to make this worth while, so they just stack them in pools.

There are three major problems with PWRs with respect to burning spent fuel:

1. Changing the geometry of the pile cannot be done while the reactor is operating (and shutdown/startup times are long)
2. PWRs and BWRs have structural constraints on the geometry of the pile
3. Light water is a poor choice of moderator for breeding fissiles from fertile isotopes, as light water absorbs neutrons reducing breeding efficiency

Reactors which favour online geometry changes, that use heavy water or graphite as a moderator, and have a good neutron economy can use multiple fuel cycles simultaneously, and can simultaneously generate power and breed fissile isotopes.

The CIRUS and Dhurva reactors have demonstrated this effectively.

Re:Radioisotope Thermoelectric Generators

[MoFoQ]

actually, you just proved how not forward thinking environmentalist (at least the ones called nutjobs by the public) are.

if the amount of radioactive stuff released (assuming that for some how, the spent nuclear fuel is lost or accidentally released into the environment...which is a big "if") is the same, I'd take nuclear energy any day....as it doesn't release the OTHER non-radioactive toxins that coal plants do....

Me and Blinky (the 3-eyed fish from The Simpsons) are just fine with nuclear power.

Re:Radioisotope Thermoelectric Generators

[fm6]

You're right, it's hypocritical to get uptight about nuclear power and ignore the health risks of coal-fired plants. But you yourself are guilty of the same evidential cherry picking. The fact that coal power plants disperse radioactive materials is meaningless — just about anything you do does this, because radioactive materials are everywhere. They don't become dangerous until you refine them and concentrate them in order to build power plants or bombs.

Plans for a new "Voyager"

[cecom]

I wonder whether there are plans for launching a new, more powerful, more sophisticated aircraft with the same purpose. After 30 years of progress we should be able to do much better, shouldn't we ? (To be honest I suspect that modern technology is less reliable than 30 years ago - the complexity is killer - but still we have to try)

Couldn't there be a very low power engine of some kind, just enough to provide a minimal thrust for, lets say, a decade. You don't need a lot of thrust in vacuum. Even small but constant acceleration should be sufficient to eventually achieve very high speed and perhaps even outrun the older spacecraft.

Re:Plans for a new "Voyager"

[aiken_d]

Just come up with a drug, abortion, porn, or terrorism angle, and the funding is yours. For the next few months, anyway.

-b

Re:Plans for a new "Voyager"

[RsG]

Technology has improved a great deal in the last thirty years. Unfortunately, some of the constraints on deep space exploration are physical, rather than engineering problems.

The limit with any engine, high or low thrust, is fuel. Essentially, any reaction drive that carries fuel with it will eventually run out (whether it's making ten Gs of acceleration over a few seconds, or .0001 G over a matter of years). You get more milage per mass of fuel as you increase the exhaust velocity (the speed of the exhaust relative to the craft), but then you're up against power requirements - it takes more and more energy to accelerate the reaction mass to higher and higher speeds. That power has to come from somewhere, and any generator system will increase the overall mass of the spacecraft, decreasing the acceleration.

Combining an ion drive with, say, solar panels will work wonders in the inner solar system, since you're getting your power for free, and firing off your fuel in small quantities at extremely high speed. In the outer system though, solar power isn't an option and radiothermic generators (RTGs) like those used on voyager are heavy, at least relative to their power output. Most other power technology we have available today would add fuel and/or maintainance constraints. RTGs and solar panals are used for precisely those reasons - because they have neither signifigant fuel limitations nor many moving parts to break down.

Plus, the engines themselves will undoubtably have a limited working lifetime - extending that lifetime to operate for years or decades will involved increasing the mass of the engine, which kinda puts you back at square one.

Something like a light sail would work better (over long distances the lower thrust is offset by the lack of fuel requirements), but that's still more in the realm of science fiction. Nuclear drive technology could also fill the gap, but the political constraints involved in putting anything fission based in orbit are huge, and we won't have fusion for decades at least (longer, if you factor in the need for miniaturization).

Re:Plans for a new "Voyager"

[Pfhreak]

Couldn't there be a very low power engine of some kind, just enough to provide a minimal thrust for, lets say, a decade. You don't need a lot of thrust in vacuum. Even small but constant acceleration should be sufficient to eventually achieve very high speed and perhaps even outrun the older spacecraft.

That's actually the exact design philosophy behind ion thrusters.

Re:Plans for a new "Voyager"

[geekoid]

Nuclear.

Launch it in bits, assemble it in space, set it free.

you can get an ion drive 1000 times more powerfull, with 100+ years of life, for less then twice the weight.

Re:Plans for a new "Voyager"

[Jett]

I am not a rocket scientist or physicist so may be completely off-base, but why not use solar powered ion drives to build up speed in the solar system and then slingshot out of the system? It might take several years to build up significant speed but as long as the craft is orbiting the sun it has all the energy it needs to maintain acceleration. It would need to spend energy maintaining orbit and eventually to break orbit, but as long as it can do that and still have enough energy to kick in for acceleration it seems like it should be able to just keep building speed.

Re:Plans for a new "Voyager"

[thatguywhoiam]

That was a great post.

I have only one comment to add: I have seen your (very amusing) sig before, but for someone who just comes upon this post for the first time and is not so familiar with some of the subtler sigs like those on slashdot... well, just read it like this. I laughed my head off:

Something like a light sail would work better (over long distances the lower thrust is offset by the lack of fuel requirements), but that's still more in the realm of science fiction. Nuclear drive technology could also fill the gap, but the political constraints involved in putting anything fission based in orbit are huge, and we won't have fusion for decades at least (longer, if you factor in the need for miniaturization). Erotic is when you use a feather. Exotic is when you use the whole chicken.

You get to the chicken part and its like.... what?

Re:Plans for a new "Voyager"

[RsG]

See the part of my post that talks about the political hurdles involving fission :-) I don't see anything wrong with that approach, but getting it past the general public wouldn't be easy.

Plus, what sort of nuclear power are we talking about here? Basic fission power (like a PWR or PBMR)? Then you have to consider the problems associated with running a miniaturized version of the reactor, with all its attendant moving parts and pressurized componants, for N* years (provide your own value for N).

Automation and redundancy will help alleviate these problems, but will add to the mass of the craft, and bring a whole new set of technical considerations into play. If we want to add automatic repair and maintainance systems, then we'd have to develop them first - and remotely operating them won't work at a latency of ~20-30 hours. Bear in mind that more of the maintainence will have to happen at the end of the reactor's life than at the beginning, which means the probe will be further away.

Building in redundancy is a better solution, but will increase the mass of the reactor, and the longer we want to keep it running, the more redundant systems we'd have to add. This doesn't even get into the problems associated with shielding the instruments, since high energy ionizing radiation can wreak havok with sensitive systems, and shielding is heavy. If your power source is giving off signifigant levels of radiation, you can forget about adding instruments for measuring those same types/wavelengths in deep space.

Using RTGs (like Voyager's) instead is a better solution, but an ineffecient one. You're trading a system that has many breakable moving parts for one that does not, but that also doesn't have anywhere near the energy output per unit of mass.

Plus, 100+ years of life? What fuel are you using? How much do you intend to carry with you? You could certainly get a lot of juice out of something that recycles it's waste, like an integral fast reactor, but no matter how you slice it, the longer you intend to operate the reactor, the more starting fuel it must carry. Plus, you've then got to have an equivalent amount of fuel for the ion drive, to make use of all that power, nevermind the aforementioned maintainace and repair considerations.

Mind you, even with all that taken into account, a probe with nuclear power + ion propulsion would still blow right by a probe launched via chemical rockets and made to coast all the way out of the solar system.

Re:Plans for a new "Voyager"

[RsG]

I think the term you're looking for is "slingshot orbit". Basically, the probe travels towards the sun at first, then uses the mass of one or more of the inner planets, or perhaps the sun itself, to alter its trajectory to take it out of the system. The pathway of the craft becomes something like a parabolic orbit, starting at the earth and ending on an escape trajectory.

Coupled with a solar/ion propulsion system, this would indeed work. You accelerate along a pre-planned trajectory, building up speed, and then use the mass of, say, Venus to launch the probe out of the system. By the time you're outside the range where solar power is a useful option, you've already used up all the fuel you're carrying for your ion drive. You then simply switch to a small RTG to provide power to the communications system, computer and scientific instruments, and coast out of the solar system.

However, the person I replied to specifically asked if it was possible to maintain an outward bound acceleration for a decade or so, and I said probably not. What we're talking about here with the slingshot idea would still be closer to what the original Voyager probes did (except that they used chemical propulsion, and their slingshot bodies were the outer planets instead of the inner ones, IIRC).

Re:Plans for a new "Voyager"

[Jett]

What I was picturing was more an orbital based acceleration, pre-slingshot. The probe would be in solar orbit using solar powered ion drives to continue accelerating (perhaps for more than a decade) until it eventually reached a target speed and then broke orbit and headed out of the system.

Re:Plans for a new "Voyager"

[RsG]

Technically, any acceleration in orbit will, by definition, change that orbit. Orbit is, after all, simply a balance between your velocity relative to the body you're orbiting and that same body's gravity. If your hypothetical probe is in solar orbit, and undergoes acceleration (in any direction), then the path of its orbit will change accordingly. Orbit isn't a physical link between bodies remember; there is no orbital "tether" linking them, merely a balance of equal forces.

You can't really "build up" velocity relative to the sun without either closing the distance to it, or moving further away. If you do close the distance, then you're back to the proposed slingshot orbit, whereas if you increase the distance, you're doing what the Voyager probes did in the first place: leaving the solar system. The very act of "breaking orbit" is the act of accelerating away from the body you're circling.

I kinda assumed you meant a trajectory that brought the accelerating probe closer to the sun first (for power reasons), then put it on an outbound parabolic trajectory by doing a close orbit around the sun or an inner planet. That is a classic slingshot trajectory, but assuming the probe is under constant acceleration, it won't take a decade to complete. The faster you accelerate the probe, the less time it will spend in the inner system, no matter what path it takes.

What you might be able to do is slingshot the probe around more than one body, say Venus first and then Mercury, but I'm not sure if there is any possible path it can take that will give you signifigantly more total time under acceleration in the inner system. Simply put, there is no way to impart a signifigant amount of acceleration while keeping the probe in the same place; the faster your velocity relative to the sun, the sooner you'll either hit it or escape its gravity well.

Re:Plans for a new "Voyager"

[raduf]

      Deep Space One was it. Faster, stronger and a lot smarter. Wasn't built to go outside the solar system, but in engineering terms is just as successful - it's done a lot more then it was supposed to.

Re:Plans for a new "Voyager"

[Shadowmist]

The other real question is whether a fusion reactor could even be made small enough to be used as a drive. It may very well be that the minimum size for a fusion power source could be many times that of it's fission equivalent.

The real thing is that if you want the kind of easy travel you see in Star Trek, you'd need a reactionless drive. Unfortunately we don't even have a theory path that might lead to practical engineering.

What's it doing exactly?

[man_ls]

Is Voyager 1 providing any useful information any more, besides the becon signal and trajectory information? Wasn't there a Voyager 2?

I'm curious what's failed on the probe so far. After 30 years, something has to have died.

Re:What's it doing exactly?

[Oliver Defacszio]

Damned near everything is dead, and it's sending back only the most basic scientific information to conserve energy levels that are already well beyond their expected date of exhaustion. I read an article not long ago (that I can't be bothered to find again) stating that only a small percentage of its original devices of science have worked at all since the 80s.

Long story short -- at this point, she's basically running flat out to see how far she can go while running on fumes. The same article stated that the new projection of its fuel exhaustion is roughly 2020.

Re:What's it doing exactly?

[man_ls]

Well, I guess that's something, seeing how far we can do and what happens when we get past our solar system.

They should really send some more, newer, faster probes out to hopefully cover that distance in less time with more available power.

Re:What's it doing exactly?

[Zarhan]

Damned near everything is dead, and it's sending back only the most basic scientific information to conserve energy levels that are already well beyond their expected date of exhaustion.

    Umm, no.

I read an article not long ago (that I can't be bothered to find again) stating that only a small percentage of its original devices of science have worked at all since the 80s.

    The Scan platform was turned off in the early 21st century. That's when cameras were turned off to save power.

    See http://voyager.jpl.nasa.gov/science/thirty.html and scroll to the end of the page.

VOYAGER 1

1998 DOY 316 - Reduction in Scan Platform power - preserve UVS and Elevation Actuator temperature (+11.0 W)

        * WA Vidicon Heater OFF (+5.5 W)
        * NA Vidicon Heater OFF (+5.5 W)

2002 - Terminate UVS operations - turn-off all Scan Platform loads (43.9 W). Date expected to change.

        * WA Electronics Replacement Heater OFF (+10.5 W)
        * IRIS Replacement Heater OFF (+7.8 W)
        * NA Electonics Replacement Heater OFF (+10.5 W)
        * Azimuth Actuator Supplemental Heater OFF (+3.5 W)
        * UVS Power OFF (+2.4 W)
        * UVS Replacement Heater OFF (+2.4 W)
        * Azimuth Coil Heater OFF (+4.4 W)
        * Scan platform slewing power OFF (+2.4 W)

    So, until 2002, V1 was used for searching UV sources among the stars, among other things. However, that doesn't tell much, since most of the work is done with particle, plasma and wave detectors and those will be working well into the 2020's.

Re:What's it doing exactly?

[Anonymous Coward]

The Scan platform was turned off in the early 21st century.

You mean four years ago?

What do you think, you're on Star Trek or something :-)

What's the problem?

[exp(pi*sqrt(163))]

Scientists still hope it will find the edge of the solar system and get into interstellar space.

The IAU just have to have a meeting and define interstellar space to start at 100 AU and the problem is solved.

How does Voyager avoid crashing into Obstacles

[aJester]

This is probably a dumb question. But here goes.

How is it that Voyager (and other probes) is able to avoid crashing into obstacles (eg: asteroids, commets, planets etc)?

Do they have some kind of navigation system that can sense an object coming towards it and alter its course?

One would think that in 30 years and so many billion miles, it must be *VERY* lucky to have avoided any obstacles in its path?

Can anyone explain?

Which Edge?

[HoneyBeeSpace]

According to this article Voyager 1 already passed the heliopause at 85 AU. So which edge are we looking for now?

Re:Which Edge?

[dedazo]

The edge of reason. Voyager will stare into the void, go psycho and start blogging about his cats.

Re:Which Edge?

[Zarhan]

Not heliopause. It passed the Termination Shock, where Solar wind changes from supersonic to subsonic speeds. It's still in solar wind. Heliopause will be coming up later.

Re:Which Edge?

[Anonymous Coward]

According to this article Voyager 1 already passed the heliopause at 85 AU. So which edge are we looking for now?

The menopause? ;)

Re:Which Edge?

[ivoras]

Um, Space - the final frontier? :)

Re:Which Edge?

[Jonathunder]

"where Solar wind changes from supersonic to subsonic speeds"

Sonic as in speed of sound? Why would the speed of sound be significant in vacuum?

Re:Which Edge?

[Durrok]

None, but it is a unit of measurement.

Re:Which Edge?

[Zarhan]

Sonic as in speed of sound? Why would the speed of sound be significant in vacuum?

It's not vacuum - there are still particles in there, albeit not much. "Sound" is a propagation of wave in a medium - this medium can be extremely sparse, but it's still there.

Near Earth, the speed of sound is around 30-50 km per second, and solar wind particles go at speeds of 400 to 700 km/sec - they are supersonic. Once the interstellar wind starts pushing against solar wind, the particles slow down.

Re:Which Edge?

[imemyself]

Subsonic and supersonic may be ways of measuring the speed of something, but the speed of sound would essentially be zero in a vacuum, right? Is it refering to how fast the speed of sound would be at sea level here on Earth? Why wouldn't they just say that the solar wind is now moving less than x km/s?

Re:Which Edge?

[Anonymous Coward]

Near Earth, the speed of sound is around 30-50 km per second

um ...

http://www.google.com/search?q=speed+of+sound+in+k ilometers+per+second

Re:Which Edge?

[Anonymous Coward]

_Near Earth_

Re:Which Edge?

[Anonymous Coward]

yeah, and as we move further from earth ... it gets colder and sound moves slower ... but that's not really the point. sound's not moving a whole lot at all in space, so this was likely used not as the *actual* speed of sound in space (which would be slower than on earth), but as a unit of measure - in which case why not use the more or less standardish 340 m/s ... which is no goddamn near 30 km/s. i mean wtf?

Re:Which Edge?

[east coast]

I don't know for sure if the bow shock has an "edge". I guess this is the reason we explore. The bottom line is that we can theorize and theorize but only time and observation will tell.

Re:Which Edge?

[Aardpig]

Then interstellar medium (ISM) isn't a vacuum, it is just very low density (a few particles per cc). At the termination shock, the solar wind changes from supersonic to subsonic, as judged by the *local* sound speed. This sound speed depends on the the temperature of the ISM, which is on the order of a few million kelvin.

Re:Which Edge?

[Zarhan]

No.

http://scienceweek.com/2004/sb040109-1.htm

Re:Which Edge?

[Anonymous Coward]

That article is about Voyager 2 passing the termination shock not Voyager 1 passing the heliopuase. The /. blurb for that article is wrong. The magnetic edge of the solar system is not aka the heliopause. The CNN article linked from that blurb says that passing the termination shock earlier than expected implies that the heliopause in that direction is closer than expected. If you RTFA to which you are posting, you would have seen This picture showing the positions of Voyager 1, Voyager 2, the termination shock reported in TFA which you cited but did not read, and the heliopause.
So what's the difference between the termination shock and the heliopause? See wiki.

Funding cut?

[Dadoo]

I heard NASA wasn't planning on renewing the Voyager funding when it was supposed to expire, last October? Did they change their minds?

Re:How does Voyager avoid crashing into Obstacles

[Svenne]

Space is big. Really big.

To put the distance in perspective...

[jd]

Voyager 1 is 100 AU away. 2003 UB313 is 97 AU and Sedna is only 90 AU away. Thus, Voyager 1 is further out than the furthest positively-identified objects in the solar system and is getting close to a theorized inner Oort cloud. I'm sure that I read that it has passed the heliopause - a shockwave that marks the end of the solar winds and the start of the interstellar wind, which would mean that the outermost planet of the solar system is outside the heliosphere. Of all the planets (and plutons) in the solar system, it alone will never feel a single breath of the solar wind.

If, as seems possible, this amateur radio astronomer can detect signals from Voyager 1, it may also be possible for amateur radio astronomers to detect the presence of very faint signals coming from the furthest objects in the solar system, as the iron within them cuts through the charged particle stream of the interstellar winds, which is all you need to generate a radio wave.

Re:To put the distance in perspective...

[RealGrouchy]

Voyager 1 is 100 AU away. 2003 UB313 is 97 AU and Sedna is only 90 AU away.

To clarify, Voyager 1 is 100 AU away *from the sun*, not [necessarily] from us. With a little fudging for the Earth's location relative to the Sun, we could say that it is only 99 AU away from us.

So any of you rapture-seekers still have another chance once it's 101 AU from the sun. (It's like the millenium thing all over again!)

- RG>

Re:To put the distance in perspective...

[jd]

The rapture-seekers are waiting for it to be 666 AU away...

Re:To put the distance in perspective...

[Anonymous Coward]

According to this picture in TFA, the Voyagers have passed the ternination shock, not the heliopause.

Re:How does Voyager avoid crashing into Obstacles

[Bob of Dole]

Space is VERY empty.
It's only slightly less non-empty when you're real close to a star or other big mass of stuff. Right now Voyager is the farthest from a star that any man-made object has ever reached, so the chances of it hitting into stuff are nearly zero.
But to answer your original question though, no, it doesn't have any kind of stuff-avoidance ability. Even if they had designed it to have that ability, by now it wouldn't have any power left to do that.

Wow! Is this thing still working? Fantastic!

[Uninstaller]

NASA sure used to build rugged, solid stuff!

Re:Wow! Is this thing still working? Fantastic!

[Anonymous Coward]

Mars rovers?

Re:Wow! Is this thing still working? Fantastic!

[sepluv]

I'd have thought ruggedness is not an issue in a vacuum. In the unlikely event that something does hit it, it's probably screwed however rugged it may be.

Will it ever find life?

[Jugalator]

I wonder if it'll ever find life, and what the scenario in that case would look like.

Maybe floating down from the skies with a note inside...
"Looks like you lost something, but jeez, it was hard to track you down with more planets than its schematic shows!"

Great

[ZakuSage]

Only one more AU until it passes 100 AU from Earth.

Re:Great

[Anonymous Coward]

Very good! You passed first grade! *gives this post a gold star sticker*

Re:Great

[PigIronBob]

not so fast, it could well be that it is already 100 AU from earth depending ont the geometry at the moment.

Re:Great

[slew]

not so fast, it could well be that it is already 100 AU from earth depending ont the geometry at the moment.

According to this document, at 8/8/2006, voyager 1 was 99.91 AU from the sun with heliographic intertial longitude of 172.8 degrees and 34.2 degrees latitude. On the same date, earth was 1.014 AU from the sun with heliographic intertial longitude of 239.3 degrees and latitude of 6.2 degrees longitude.

Confirmation of the fact that it's already passed 100.7AUs is of course is left as an exercise for the reader... ;^)

Re:Great

[Anonymous Coward]

Only one more AU until it passes 100 AU from Earth.

Or half a year, depending on which side of the sun we are when the measurment is made.

Re:How does Voyager avoid crashing into Obstacles

[jguthrie]

Douglas Adams put it fairly well:

Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the drug store, but that's just peanuts to space.

The reason it hasn't run into anything is because space is basically empty. There's very little out there to hit and what is there is a long way from anything else. So, not it's not *VERY* lucky to have not hit anything. If it had hit something, it would have been very *UN*lucky.

What's the point? In another 30 years...

[manifoldronin]

All the data sent back will be lost by NASA anyways.

CMOS Worked Out After All

[druske]

Too bad the CDP1802's architect, Joe Weisbecker, didn't live to see his microprocessor become the first in interstellar space. Coincidentally, this month also marks the 30th anniversary of his Popular Electronics article on the COSMAC ELF; Nuts and Volts magazine is covering it.

Re:CMOS Worked Out After All

[Dan East]

I can't believe it. You post a message about a CPU on Slashdot that has an instruction called SEX and didn't try to make a joke out of it? You've really let us all down.

using the SEX instruction, you can select any of the 16-bit registers to be the index register.

Kinkiest CPU I've never coded for.

There, that's my feeble attempt to make up for your post's deficiency.

Dan East

Re:CMOS Worked Out After All

[bradkittenbrink]

using the SEX instruction, you can select any of the 16-bit registers to be the index register.

Kinkiest CPU I've never coded for.

There, that's my feeble attempt to make up for your post's deficiency.

Go figure, a slashdotter demonstrate feebleness at using the SEX instruction for its optimal purpose.

Re:CMOS Worked Out After All

[druske]

"I can't believe it. You post a message about a CPU on Slashdot that has an instruction called SEX and didn't try to make a joke out of it? You've really let us all down."

Well, sure, SEX is great, but SEP is way cooler. (Er, maybe I've been married too long...)

Re:CMOS Worked Out After All

[Opportunist]

Maybe he was afraid he might end up on the index.

You know how those religious freaks can be. The least bit gets registered, and if there are 16 of them...

Ok, ok, my attempt wasn't much better. Hey, I tried.

Speed over time

[SuperBanana]

Couldn't there be a very low power engine of some kind, just enough to provide a minimal thrust for, lets say, a decade. You don't need a lot of thrust in vacuum. Even small but constant acceleration should be sufficient to eventually achieve very high speed and perhaps even outrun the older spacecraft.

If getting from A to B as fast as possible is your goal, you want to get as much of your acceleration done as fast as possible. For example, at the race track, it's better to be going 1MPH faster exiting a turn onto a straight section, than to end up 1MPH faster at the END of the straightaway.

It'd be much beter to do a big burst, then trickle- than to trickle all the way.

Re:Speed over time

[drinkypoo]

The problem is that you also have to stop at the other end. The best possible scenario for minimum time of flight, assuming current technology, is to accelerate at maximum for half the journey, flip around, and decelerate at maximum (also known as accelerating along the inverse of your original vector.) There is little to be gained by using any other method, unless you don't have enough fuel to do that, in which case you accelerate until a little less than half your fuel has been used up, and then coast until you're at the proper place, and decelerate until almost al l your fuel is used up. (A small safety margin is always a good idea.) This is a little simplistic, depending on the mass of your fuel; it will take less fuel to do your deceleration, because you've been burning fuel, and have reduced your mass, thus you can probably burn a bit more than half on the outward leg.

Re:Speed over time

[Anonymous Coward]

But, if point B is at infinity... then all that really matters is the end speed.

Re:How does Voyager avoid crashing into Obstacles

[jmorris42]

> One would think that in 30 years and so many billion miles, it must be *VERY* lucky to have avoided
> any obstacles in its path?

> Can anyone explain?

Ok. Since you apparently skipped science class I'll keep it simple.

Well first off, space is big. Really really big. Mindbogglingly big. And second it is almost entirely empty. So the odds of it hitting anything is pretty much zilch, especially out where it is now.

238Pu != 239Pu

[Anonymous Coward]

The name of a chemical element only conveys its chemical properties. If you want to discuss nuclear properties you have to specify the isotope you're talking about. 238Pu is used in radioisotope thermoelectric generators. 239Pu is used in nuclear weapons. They are not the same and cannot be converted from one kind to the other easily.

Re:How does Voyager avoid crashing into Obstacles

[rpj1288]

I love how the all those responses quoted Douglas Adams.

AU/km/mi

[H0NGK0NGPH00EY]

Yesterday, Voyager 1 passed 100 astronomical units from the sun as it continues operating after nearly 30 years in space. That is about 15 billion kilometers or 9.3 billion miles as it travels about 1 million miles per day.

I'm not quite sure I've got a grasp on how far that is. Could you give it to me in # of songs, or Libraries of Congress or some other similar standard?

Re:AU/km/mi

[Masque Noir]

That would be roughly 137 billion football fields to use a very conventional mean of measurement.

Re:AU/km/mi

[jiawen]

For the Americans in the audience, that would be the length of 1,636,023,620 football fields.

For the non-Americans in the audience, that would be 15 billion kilometers.

Voyager passes 100AU

[StikyPad]

breaking the previous record of 99.99999AU, also set by Voyager I... the day before.

Re:Voyager passes 100AU

[Anonymous Coward]

What do you mean by "day"

Size doesn't matter, so more acuratly

[geekoid]

Space is empty. Really empty.

Re:Poor V'ger

[MS-06FZ]

I wonder how long until it comes back carrying half the solar system with it looking for it's maker?

Nomad's gonna kick your ass for imperfectly spelling "its"...

If the aliens transformed it now, it'd pretty much be back here already, since its cloud is 82 AUs in diameter. (Screw that hippie "Director's Cut" edit that claims it's just 2AUs...)

100 AU doesn't seem that far...

[iambarry]

100 AU over 30 years. Seems to me I've gone almost as far in the same period of time.

Quick math :

-The earth travels (about) 3.14 AU / year
- 3.14 * 30 = 94.2 AU over 30 years

(note: I make math errors all the time. No doubt someone will correct this one if its wrong)

Why isn't voyager faster than the earth given it started off going as fast as the earth, and quickly accelerated from that point during takeoff?

Re:100 AU doesn't seem that far...

[Anonymous Coward]

Wouldn't it be 6.28 AU per year?

1AU=distance from earth to sun (radius of orbit), 2AU=diameter of orbit
2AU x pi = ~6.28AU * 30yrs = ~188AU

Re:100 AU doesn't seem that far...

[Chirs]

Voyager has travelled a lot further than 100AU over the years. It's just that now it is 100AU away from the sun in terms of radial distance.

It still kept the tangential velocity...we just added radial velocity.

Think of it traveling in a spiral, while we're going in a circle. Eventually we end up far apart.

Re:100 AU doesn't seem that far...

[iambarry]

yup...that seems right...that means we've gone twice as far as Voyager in the same amount of time?

Re:100 AU doesn't seem that far...

[ArbitraryConstant]

100 AU over 30 years. Seems to me I've gone almost as far in the same period of time.

Yeah, but Voyager managed to do it without going in circles.

Re:100 AU doesn't seem that far...

[greylion3]

Quick math :

-The earth travels (about) 3.14 AU / year

A little too quick math there.
The Earth orbits 1 AU from the Sun, so the diameter of its orbit is 2 AU, the circumference is 2*PI = 6.283.. AU, which is the distance it should travel in one year.
30 years - about 188.5 AU traveled.

If Voyager I initially was accelerated/rocket-propelled off in the opposite direction (or so) of what the Earth was traveling, it's going slower than the Earth..

Re:100 AU doesn't seem that far...

[Anonymous Coward]

You should also the fact that, as the earth spins, we move too. Someone living in Panama travels more than someone in Poland.

Re:100 AU doesn't seem that far...

[Sinical]

Circumference = 2*Pi*r
r = 1 AU

You're off by a factor of 2. Other points as noted.

It's easier when you don't have to fight the Sun, isn't it.

It's further oort than that

[jmichaelg]

Thus, Voyager 1 is further out than the furthest positively-identified objects in the solar system and is getting close to a theorized inner Oort cloud.

100 AU is nowhere near the Oort cloud. Sedna's orbit is highly eccentric ranging from around 92 au out to around 850 au. The Oort cloud is even further out at 50,000 au.

Re:It's further oort than that

[jd]

Sedna is believed to be part of an "inner Oort cloud", theorized because it's far too far out to be almost anything else, but can't be part of the "regular" Oort cloud because it's far too close. I think this is on the Sedna wiki page and maybe Brown's page as well, and I think it gets a brief mention on the Oort wiki page on top of that. But the combined sources say next to nothing beyond talking of this "inner Oort cloud", so I can't put in anything beyond a brief mention that it is theorized and -if the theory is correct- that Voyager 1 would need to be getting close to such a cloud.

Propulsion

[Chronus]

I couldn't glean it from wiki but what kind of propulsion and stabilization systems does the probe have? I assume it still needs to correct its orientation every now and then.

Re:Propulsion

[sr180]

Hydrazene Thrusters to keep orientation. Other spacecraft have switched to gyroscopes to stabilize the craft. Voyager 1 should have enough fuel to last to 2020..

Re:How does Voyager avoid crashing into Obstacles

[exp(pi*sqrt(163))]

Um...why would someone aim a space probe at an asteroid, comet or planet and so demolish a very expensive piece of hardware designed for long term space exploration? Is it really necessary to point out that NASA are typically (but not always!) sensible enough to choose to aim their probes so that they don't crash into asteroids, planets and comets?

Re:How does Voyager avoid crashing into Obstacles

[Anonymous Coward]

Only in the short term.. given a long enough timeframe, its odds of running into something eventually are 100%.

On the rebound

[Linker3000]

Wouldn't it really freak out the scientists if Voyager disappeared from 'view' and then later started to come towards us again from the opposite direction!!!

Re:On the rebound

[zakezuke]

Wouldn't it really freak out the scientists if Voyager disappeared from 'view' and then later started to come towards us again from the opposite direction!!!

Voyager I does not contain an AOL CD.

Re:Poor V'ger

[elmCitySlim]

Haha. I saw that episode for the first time yesterday (I had a recording from Saturday's orgional showing). It will be more interesting if Voyager gets its programming skewed from intersteller sex with another space probe.

Scientists still hope...

[NoseBag]

Scientists still hope it will find the edge of the solar system and get into interstellar space.

Just keep going straight out with the sun at your back - you'll get there.

Obligatory Seinfeld

[Fear the Clam]

Scientists still hope it will find the edge of the solar system

What's to find? It's not like it's hidden. Just keep going and you'll trip over it.

Re:How does Voyager avoid crashing into Obstacles

[whoisjoe]

Space is big. Really big.

Are you saying it's big even compared to the walk to the chemist?

Re:How does Voyager avoid crashing into Obstacles

[PresN]

It's when they want to hit something that they have problems...

Rodzilla!

[LouisZepher]

If I've ever learned anything from about radiation exposure from low-budget Japanese films, I think that the missus would be rather pleased...

Re:Rodzilla!

[RsG]

If I've ever learned anything from about radiation exposure from low-budget Japanese films, I think that the missus would be rather pleased...

She'd be less pleased when it started breathing fire...

Of course, a round of anti-biotics will clear that right up! :-P

Re:Poor V'ger

[cnettel]

The cloud would reasonably be centered around the current position, so the closest point would still be some 60 AU away.

URL to a photo?

[kimvette]

[...]The spacecraft are traveling at a distance where the sun is but a bright point of light[...]

Are there any photos of the sun from that distance? I've never seen photos looking back at the solar system from those spacecraft published. Even if it is only points of light, it'd be neat to see some photos from Voyager with the sun and visible planets highlighted to get some sense of scale of our tiny corner of the universe.

Re:URL to a photo?

[ShoreDiver]

A quick calculation: Diameter of the Sun: 1 million miles 100 AU's: 93 million miles * 100 = 9300 million miles Angular size of the sun as viewed from 100 AU's: 1/9300 = arctan (x), so x = about 22 seconds of arc. Just 2/3 the size of what that bright dot Jupiter looks like to us! And I suppose the Sun would appear 1/100^2, or one ten thousanth as bright? Hope all that is right!

Re:URL to a photo?

[Anonymous Coward]

Even if it is only points of light, it'd be neat to see some photos from Voyager with the sun and visible planets highlighted to get some sense of scale of our tiny corner of the universe.

Well, if the sun is a tiny point of light from Voyager's position, only the planets on the far side of the sun wiuld be illuminated (the rest would have their dark side, or only a partial disc, visible to Voyager). But if the sun is just a tiny point, the illuminated planets would be vastly smaller and vastly dimmer points. So, no see

We can barely see the moon during daytime at our distance, so I expect the planets would be pretty much inviible.

Re:URL to a photo?

[MS (404)]

To get some sense of scale Celestia is a very good help.

Re:URL to a photo?

[ender81b]

IIRC, the camera platform has been shutoff for the greater part of two decades now and it's highly unlikley they could turn it back on (and be functional) or that they would have the power to do so.

Re:URL to a photo?

[SamSim]

Photos of the Sun from that distance are very unremarkable IIRC. It just looks like a starfield. None of the planets are visible from that distance. At all. Which is sobering.

The pale blue dot photo which some of my sibling posters mentioned is well worth a look, however.

Re:URL to a photo?

[Zarhan]

High resolution TIFF available at

http://photojournal.jpl.nasa.gov/catalog/PIA00451

Re:Poor V'ger

[MS-06FZ]

Aw, damnit, you're right! :)

It'd at least blot out a whole lot of the night sky, though. If we're on the right side of the sun to see it right now, that is.

Here is what it is still doing?

[Anonymous Coward]

Here are areas of investigation:

        * Magnetic field investigation
        * Low energy charged particle investigation
        * Plasma investigation
        * Cosmic ray investigation
        * Plasma wave investigation

These five instruments are:

        * MAG Magnetic field investigation
        * LECP Low energy charged particle investigation
        * PLS Plasma investigation
        * CRS Cosmic ray investigation
        * PWS Plasma wave investigation

In addition, there are data being collected from two science instruments that do not have official science investigation teams associated with them. These instruments are:

        * PRA Planetary Radio Astronomy Subsystem
        * UVS Ultraviolet Spectrometer Subsystem

Source:
http://voyager.jpl.nasa.gov/science/index.html

Re:How does Voyager avoid crashing into Obstacles

[slew]

> Only in the short term.. given a long enough timeframe, its odds of running into something eventually are 100%.

Depends on the nature of the universe.

If you believe in that the universe is uniformly expanding, then every point is at the center of the expansion. Since the velocity of voyager isn't that high (relativistically speaking), there is at least some chance that it could eventually get to a state where nothing even going at speed of light can run into it, ever. ;^)

Ooh ah

[Anonymous Coward]

Due to a genetic condition, I was born with six extra fingers. That being the case, can we have a party when Voyager 1 passes the 0x0100 AU mark?

Flight Team of Ten

[davidbofinger]

[...] the flight team, which is now down to only 10 people.

Not to put down the important job they are doing, but why does Voyager need a flight team of ten? Seems like the only real job is recording data off a few surviving instruments: it's not like when Voyager was near the outer planets and they had to make decisions about what to look at, etc.. So what do they do?

Re:Flight Team of Ten

[cyclone96]

There's a nice article on the flight team from a few years ago here.

Taking an educated stab in the dark (I've done satellite operations for NASA, but not on Voyager), I'm guessing that you've got a couple that deal with trajectory (where it is in space), one that handles the scheduling of time on the Deep Space Network downlink stations and queing command activities on the spacecraft itself, and maybe 3 that handle sustaining engineering on vehicle hardware systems like electrical, communications, attitude control (including momentum wheels and propulsion), and science instruments. Maybe 1 or 2 that handle the onboard computer and flight software. Finally, probably 1 or 2 maintain the ground data retention system and support workstations, plus a manager for the whole shebang.

It's also almost certain that most or all of these 10 people work on other JPL projects, too.

Re:How does Voyager avoid crashing into Obstacles

[Hotawa Hawk-eye]

Well, sometimes they intend to cause an impact.

You will want to see the Pale Blue Dot photo

[Anonymous Coward]

You will want to see the Pale Blue Dot photo - you should be able to find it on wiki - somewhere near Carl's page

Re:You will want to see the Pale Blue Dot photo

[kimvette]

Thanks! :)

Is this Matt from Tacoma?

[satan's daughter]

We miss you! We want to send you pictures of a station wagon we saw at a car show this summer, even if you hate us because we are friends with Pleiades.

oops..

[slew]

degrees != radians, it's only 98.9AUs...
shuda known 172.8 and 239.3 are pretty close...

Fastest as well as furthest?

[mysticgoat]

It is very likely that no human has ever thrown any artifact farther than the Voyagers. But are these also the fastest artifacts humans have ever produced? 1 million miles per day is about 11.6 miles per second, so I'm thinking these are the fastest things ever built on Earth?

Re:Fastest as well as furthest?

[Yunzil]

It is very likely that no human has ever thrown any artifact farther than the Voyagers. But are these also the fastest artifacts humans have ever produced? 1 million miles per day is about 11.6 miles per second, so I'm thinking these are the fastest things ever built on Earth?

The New Horizons probe is much faster.

Did I ever tell you guys about the time...

[i41Overlord]

that it tried to get onto my Quake server?

We were trying to fire a game up, and on comes Voyager 1, with its 26 hour ping time. We all laughed and then booted it off.

Re:Did I ever tell you guys about the time...

[Schraegstrichpunkt]

Of course, since Voyager 1 had set pushlatency -100000, it got a good 26 hours of fun fragging you all before it finally got the message that it had been kicked and its frags didn't count.

Re:Did I ever tell you guys about the time...

[Anonymous Coward]

Well, you're not laughing when v'ger comes back to looking for his Kicker.

The craft cannot possibly last forever.

[Typingsux]

I realize it may never impact a large object. What about cosmic rays? Will they not microscopically rip the craft apart over milennia?

Where Is It?

[Anonymous Coward]

Scientists still hope it will find the edge of the solar system and get into interstellar space.

Hey, scientists, just tell it to keep going in a straight line - you can't miss it..

Voyager is quite a milesonte for mankind

[BoberFett]

Yet, somehow, it makes me feel smaller than ever.

I thought...

[RuBLed]

Voyager got a deflector dish.

Re:Poor V'ger

[solitas]

Speaking of Nomad: http://echosphere.net/star_trek_insp/insp_nomad.jp g

Re:How does Voyager avoid crashing into Obstacles

[Anonymous Coward]

Are you saying it's big even compared to the walk to the chemist?

That's just peanuts compared to space.

The Universe

[tka]

is about 14 billion light years or so wide. 15 billion kilometers = 0.00158553512 light years. Not very far when compared to astronomical distances but it's still nice.

Re:The Universe

[Anonymous Coward]

So it would take about 7,500 years (rough calc) to reach Alpha Centauri (if it were pointed that way which it isnt).

The Space Family Robinson did it quicker than that!

RIAA

[m874t232]

I think you're on to something: this seems like a good idea to finance research into manned space travel. Just think how much space travel would advance once the RIAA figures out how to have their lawyers hand-deliver a cease-and-decist letter.

(Of course, given their ethics, they'd just be working on a survivable one-way trip, but that's still quite a feat.)

Power comes from?

[madbawa]

15 billion miles is a hell of a distance. What powers the Voyager? Even if its solar powered, what kind of a transmitter can signal from 15 billion miles? I would like to know the technology in the transmitter.

Re:Power comes from?

[Shadowmist]

As discussed before, Voyager is powered by radioisotope generators which derive power from the heat produced by radioactive decay. It's not a very efficient power source but it is reliable and long term the two neccessities for a mission of this type.

The answer to the second question is that it's an ordinary radio transimitter using the X-band frequency as I recall. The key to our reception is not Voyager's radio but the fact that we have very powerful tranceivers that can both receive it's very weak signal and transmit with enough boost so that Voyager's receiver can pick up commands.

NASA tape management

[Anonymous Coward]

I'm sorry. Did you say Voyager 1? Hold on a minute. ...
No, I don't think we have ever launched anything with that name.

Pitstop

[landoltjp]

I wonder how long until it reaches the next Starbucks?

Re:Pitstop

[gold23]

About 13 seconds. And the next 2 minutes after that. And...

Does anyone know

[teflaime]

what the current radio lag is from Vger? Are we talking weeks? months?

Speed is relative

[Opportunist]

unless you're getting close to c, of course.

Voyager is moving relativ to Earth, and relative to Earth it moved 100 AU. "Absolute" (i.e. relative against, say, the center of our galaxy) it might have moved anything from 6AU to 194AU.

Will Voyager return????

[Nonillion]

Isn't it possible that Voyager 1 will eventually come back? It would tend to make sense that space craft would have to achieve some sort of 'escape velocity' to get into 'interstellar space'. I would hazard to guess that Voyager 1 is basically in one highly elliptical orbit; and may come back in say 50 years or so. But this time not as VGER :)

Re:Will Voyager return????

[Yunzil]

I would hazard to guess that Voyager 1 is basically in one highly elliptical orbit; and may come back in say 50 years or so.

No, it's going fast enough to escape the Sun's gravity, so it's on a one-way trip to the interstellar void. :)

Re:How does Voyager avoid crashing into Obstacles

[Teancum]

If that isn't the basis of one damn good SF story, I don't know what one would be. Imagine if some bacterium (this is fiction, so anything is possible) "evolves" for some sort of bizzare sentience (its ancestors snuck into the clean room when the Voyager was being preped) and suddenly discovered that the entire universe is just the Voyager spacecraft, as far as can be detected with any instruments.

Food for thought.

Metric Is Better!

[soloport]

Damn! We (the US) should really consider switching to the metric system. Look how much farther you get in 30 years -- 15 billion kilometers vs only 9.3 billion miles.

Exploitation and take over

[Hemi Rodner]

I was wondering if the Voyager is protected from take overs. Can anyone control it herself instead of Nasa, and then do stupid things with it?

ron ballke?

[Lawrence_Bird]

what ever happened to that dude?  He used to do like a weekly or monthly email update on the vgers and pioneers. 

Re:ron ballke?

[Anonymous Coward]

I made that mistake. For Years. Ron can be Female, too...
( No, I dont know what happened to her, or her career at NASA )

What Stargate should do

[jameskojiro]

They should have a show where they pass the Voyager 1 space craft and laugh at it...

Re:Star Trek linked to pedophilia?

[Anonymous Coward]

The majority of people I know in any demographic group have "at least a passing interest in Star Trek". This makes as much sense as saying a majority of offenders have type O blood.
As a local in the tech industry, I can tell you that Toronto Police has a fixation on their theory that anyone who has a passing interest in science and fantasy fiction and computers is probably a sex offender. They like to make a big deal about it whenever they arrest a programmer with a comic book collection for any reason, including this sunner's alleged terrorism busts.

Re:How does Voyager avoid crashing into Obstacles

[Bob of Dole]

The universe-is-a-spaceship has been done before. Most memorably as "Orphans of the Sky" by R.A. Heinlein. A generational ship forgets they are a generational ship, so the universe is just the ship. No windows in the habitable areas, so they don't even know the ship is moving ("The universe is moving?")

Someday we'll retrieve it!

[mwilliamson]

I really think Voyager I and II will be retrieved and end up in the Smithsonian. I'd even be willing to bet this will occur sometime in my lifetime. (I'm 31). I'm looking forward the exibit.

"Dwarf Plant" sounds bad.

[Kaki Nix Sain]

I mean stupid and unscientific. Couldn't they have found a good prefix to mean the same thing. Call 'em "deciplanets" or "mesoplanets" or "microplanets" or "semiplanets" or "subplanets" or even "infraplanets". Whichever has the best shades of meaning. But "dwarf"? I know it means something that is small compared to other members of its species. Still seems like some prefix could have done the job. Heck, "pluton" sounds way cooler.

Re:"Dwarf Plant" sounds bad.

[Kaki Nix Sain]

Crap I totally put this on the wrong story. Sorry, everyone. Feel free to kick me.

As for Voyager 1. I've put a tack on the wall next to my poster of the solar sytem, out at the proper scaled distance. "Good job" to all those that worked on that project, our far-off emissary into the void.

But, you know, "dwarf planet" still sounds dumb.