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Whisper Heard From Pioneer 10
Irishman writes "NASA has heard from the Pioneer 10 spacecraft for the first time since March. Unfortunately, it is too faint to get scientific data from the craft. CNN has the story here.
Considering that the craft is twice the distance from the Sun as Pluto is and that it has spent 30 years subjected to space, this is amazing! Now if only computer manufacturers could make equipment even remotely this sturdy."
In space, all the craft needs to deal with is the occasional decresing chance of a cosmic or solar ray, or perhaps a micrometeorite. Earth's changing climactic conditions and microbes are far more destructive to technology than is space!
The space stuff is actually far too fragile to work on Earth, and is designed from a payload perspective to be light, not Earth-durable.
Exactly. Pioneer 10 cost ~$200 million to design and build, plus another ~$150 million to launch and operate. Here's more information on it.
From the Pioneer Status web page:
Pioneer 10 distance from Sun : 81.86 AU Speed relative to the Sun: 12.228km/sec (27,355 mph) Distance from Earth: 12.10 billion kilometers (7.52 billion miles) Round-trip Light Time: 22 hours 25 minutes
There was one more Pioneer 10 contact on 12/5/02. The Deep Space Station (DSS) near Madrid (DSS-63) found the signal but could not lock onto the receiver, and so no telemetry was received. The signal level was just under the threshold value. The uplink from DSS-14 at Goldstone, sent 12/4/02 at a power level of 325 kw, confirmed that the spacecraft signal is still there (Round Trip Light Time = 22 hr 24 min).
Project Phoenix also picked up the signal from Pioneer 10 at Arecibo in Puerto Rico.
LARRY LASHER, PIONEER PROJECT MANAGER
(Copyright NASA)
It would be nearly impossible to send repeaters out behind a space probe because virtually all of the probes sent out by NASA are slingshot off the gravity of the planets that they flyby. By the time a trailing repeater got there the planet would be in a different place -- thus no slingshot and no way to follow/keep up with the original probe.
While it's interesting that it's still working, there is nothing out there to study. The Kuiper belt is too low density for there to be any chance for Pioneer to see anything, and the first Kuiper belt object wasn't even discovered until 1992 anyway, so at time of launch, there was nothing known outside the orbit of Pluto.
In about 2 million years it'll be in the vicinity of Aldebaran. It was sent out originally as a deep space probe.
Sending out probes is cool when we can collect info, but it's not really useful if the data isn't able to be processed.Just finding it is useful information. From this, physicists can map its path and start to make observations of what space is actually like out there. They have used the some sparse readings in the past to investigate everything from cosmic rays to gravitational mechanics.
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"Now if only computer manufacturers could make equipment even remotely this sturdy."
It's called the Compaq Nonstop Himalaya. Each processor runs every calculation twice, in parallel, and compares the answers when done--if they do not match, it tries again. If they do not match again, the processor state is saved then restored in one of the "hotspare" processors. The memory uses a special, extra high-reliability (and extra slow) ECC algorithm. The server itself has integrated battery backup, variable speed fans which adjust for the death of other fans, and each system is immensely expandable without ever being rebooted or shut down.
An acquaintance of mine works for a company which has a Nonstop with an uptime of nearly ten years.
Remember the Tandem?
Note that the Nonstop isn't much more reliable than IBM's Z series mainframes, which basically never die either.
Ironic, isn't it, that a company famous for making desktops which are essentially crap, makes one of the most reliable servers on earth?
Er, back on topic, isn't Voyager significantly farther from the sun than Pioneer 10?
Computer Science is no more about computers than astronomy is about telescopes. --E. W. Dijkstra
I'm sure that you can get almost anything you like as sturdy as Pioneer 10 if you're prepared to spend $300 million on getting it built...
(Pioneer 10 cost $75 million in the 1970s - which corresponds to something like $300 million today.)
Just continue to wander out in space. In order to 'turn around', there would have to be an object out there for it to interact with, and there isn't. The last chance for it to do so was when it swung around Jupiter in 1973. That was it's primary mission, to study Jupiter. The design didn't allow Pioneer to orbit Jupiter like Galileo did, so it had to swing out into space. They used it to study the outer solar system between 1973 and 1997, but that was just becaue it was available.
Just for interest, Pioneer is powered by the decay of Plutonium 238. This isn't a reactor, the decay is natural.
American Heritage Of Invention and Technology had terrific story on Pioneer 10 some years back. I found the text here on the personal web page of its author Mark Wolverton. Worth a read if you're interested.
Pioneer 10 was meant to do a fly-by of Jupiter and Saturn. To quote the current project manager,
So it's going wherever it happens to be headed, but we didn't send it that way on purpose.
The Mongrel Dogs Who Teach
Communications were maintained via (1) the omnidirectional and medium-gain antennas which operated together while connected to one receiver and (2) the high-gain antenna which was connected to another receiver. These receivers could be interchanged by command to provide some redundancy. Two radio transmitters, coupled to two traveling-wave tube amplifiers, produced 8 W at 2292 MHz each. Uplink was accomplished at 2110 MHz, while data transmission downlink was at 2292 MHz. The data were received by NASA's Deep Space Network (DSN) at bit rates up to 2048 bps enroute to Jupiter and at 16 bps near end of the mission.
Is the solar system larger than the orbit of Pluto? If so, what defines it?
I'm no expert, but I believe that the edge of the solar system is generally considered where the sun no longer has any influence. Beyond Pluto (Pluto is about 39.5 AU from the sun) the sun continues to have influence in the form of solar wind (thought to go out to around 100 AU). Many scientists also believe that many object exist outside the orbit of Pluto.
eMelody Web Directory add your site today!
Both of the Voyager spacecrafts are pushing the edges of solar influence as well.
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Inventor of the term 'pardon my French'.
True, radio communications just aren't going to cut it. We can pick up radio-type signals from stars, but these are... well, not to put too fine a point on it, fucking stars.
I seem to recall reading that Earth outshines the sun in certain radio bands. Citation lost to the mists of time.
You could beamcast signals to another star easily enough, especially with a (very large) space-based dish. The problem is aperture size, not source power per se (you want the beam to have low divergence). While optical transmission doesn't require as large a dish for a given divergence, it does require far more energy to be detectable. You have to be bright enough to put a minimum of about 10 photons per $sample_period per $detector_area at the destination star system to be detected, and visible photons are many orders of magnitude more energetic. (I'm assuming we're doing detection by correlating many samples, instead of trying to dump enough energy to outshine the Sun in one pulse).
Broadcasting instead of beamcasting, we'd need vastly more power to be detectable at all.
Your question is a good one. What does define our Sun's reach? /. regarding the Solar System and Kuiper Belt. I has links to three sites with detailed info.
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Here is an earlier article on
http://science.slashdot.org/article.pl?sid=02/10/
http://news.bbc.co.uk/1/hi/sci/tech/2306945.stm
http://www.expressindia.com/fullstory.php?newsid=
http://www.smh.com.au/cgi-bin/common/popupPrintAr
There is an interesting (older) article linked from this one regarding the fact that both Pioneer probes (10 and 11) are closer than they should be based on the laws of gravity and Newtonian physics. JPL scientists postulate the existence of some sort of "hyper-gravity", as the effect has been shown equivalent on both probes, although each was sent in opposite directions.
//Nanoox
It would be interesting to find out whether this effect has also been observed on the Voyager probe which surpassed both Pioneer probes as the most distant man-made object in 1998.
It doesn't say anything of the kind. The RF power output of Pioneer is miniscule:
Two radio transmitters, coupled to two traveling-wave-tube power amplifiers, each produced 8 W of transmitted power at S-band. source
So, we are picking up a signal from either an 8W or 16W transmitter (not quite sure if they are both used at the same time), 12 billion kilometers away. We talk to the Pioneers by sending a 325,000W signal. More power, more distance before it attenuates below the noise floor. Pump out enough power in a tight enough beam, and there isn't any reason to believe that we couldn't send signals all the way to the nearest few stars. Round Trip Time would be a bit of a pain, not to mention the time it might take to translate on both ends, but not technologically infeasible.
Exactly how much power you would have to transmit to be heard depends on many factors, such as the frequency chosen (which might be attenuated or masked by interstellar phenomena), the sensitivity of the receiver, the size of receiving dish, the directionality of the beam, the length of the transmission, the properties of the error correcting codes, the mathematical properties of the transmission (whether it could be distinguished from physical processes even IF it is received) etc. etc. etc. So I can't give you a single answer.
Barring some freak gravitational occurrance, never.
DS1 is in a solar orbit and won't be leaving the solar system.
If you don't believe me, read the last log entry.
"From my cold, dead hands you damn, dirty apes!" - CH
Yes, plutonium 238 isn't a natural isotope. You don't want a natural isotope in this application, because you want a short halflife so that there is enough decay to make a significant amount of heat, which is converted to electricity through thermoprobes. The 92 year half life is perfect. We're about 1/3 of the way through a half life, so the pile will still be outputing 80% of the heat of the original pile. Unfortunatly the thermocouples have degraded, which has reduced the power output, however it's still much better than if they'd put a reactor onto the probe, which would have failed by now.
gorilla asks:
6 8.stm
2 5thSep02/ gravity.htm
>Why bother?
Because you never know where new knowledge may appear. Effective tools should be maintained as long as they are useful.
Specifically, it was data from the supposedly now 'retired' Pioneers 10 and 11 that alerted scientists a couple years ago that there may be some problems with our current understanding of gravity.
After tracking the faint signals from the probes, scientists were able to determine that neither probe had traveled as far as it should have by a substantial margin, and they have now been able to eliminate most proposed explanations for this sun-ward acceleration, including nearby large undetected masses (Pioneers 10 and 11 are headed out of the solar system in nearly opposite directions), unaccounted effects in the the propulsion systems, space debris, solar wind, etc etc. Recently, this same anomalous acceleration was measured for the Galileo and Ulysses probes. The ESA is designing a series of missions to look into this anomaly and others related to gravity.
Mystery force tugs distant probes
http://news.bbc.co.uk/1/hi/sci/tech/13323
ESA to look for the missing link in gravity
http://www.globaltechnoscan.com/19thSep-
Preventive War is like committing suicide for fear of death. - Otto Von Bismarck
Here's a graph which includes the logarithm of the temperature Voyager's reading of the solar wind plasma which surrounds it. Converting back from the logarithm, this temperature displayed here varies from about 5000 K to about 50000K. Of course, in such high vacuums the heat transfer is minimal. Another source for more detailed data is here.
Placing most electronics in 1 atmosphere of air at those temperatures would boil them, but that's as irrelevant as the 5 K comparison as this is high vacuum.
It's very hot... in space. KHAAAAAAN!
... and ...
:D
"22 hours later, from 79.4 AU, DSS 63 acquired the downlink on time at -183 dbm. After peaking the signal to -178.5 dbm, they locked the telemetry at 16 bps with SNR of -0.5 db."
Sounds JUST like my 56k modem
Now if only computer manufacturers could make equipment even remotely this sturdy.
...
I have a Microsoft mouse that came with my new computer about two years ago. Since it's made out of nonreactive plastic it could likely survive for millions of years out in space.
Oh, whoops, I just read the article (what're the chances of that?). Although it would exist for a long time, it already lost its function a month after I bought it
Cyde Weys Musings - Scrutinizing the inscrutable
formed from the beta decay of U238. However U238 usually alpha decays first, so generally there is not much Pu238 in a uranium sample. Either way, the result is the same, U234 is formed after 1 alpha decay and 2 beta decays.
I worked for 10 years in a facility that built custom ICs for NASA. Most of the ICs in almost every historic space mission was produced by this facility. When I was there we used a lot of 6805 varients. They were NOT the same parts that you could buy off the shelf. First, the die we started with was processsed specificly for the application. Second the construction techniques are far different then commercial parts. Third, we screened the *** out of them, as in start with 40 parts for a deliverable of 4 units. The StrongArm is a industrial device to begin with. It is not a commercial grade part. Industrial grade ICs are already part of the way there, to level S.
Any ways, the real killer for space craft, besides being able to survive launch, is temperature. It is not just the extreams, NASA parts work from -55c to +125c, it is the tempurature cycling. Tempurature cycling stresses wirebonds, package seals, and even the integrety of the substrate. Temp cycling can even drive out chemically bound water that can react with ionic contaminates to produce corrosives. This can degrade bond wires, the substrate metalization, and on one occasion, a resistor on the die itself.
Building a spacecraft from parts from Radio Shack is like fighting a modern navel battle with bass boats. Though a bass boat and a destroyer both float, have GPS, radios, radar, and sonar, there is a lot of differents in construction. I'd but my money on the destroyer.
Imagine, please, that you have a pipe 1m in diameter stretching from just past Earth's atmosphere to the Alpha Centauri system. (Ignore the engineering difficulties, please.)
Can you guess how much all the contents of that pipe would weigh?
Less than a kilogram.
Considerably less than a kilogram.
I would tell you just how tiny, but you wouldn't believe me. I'll let you do the math: the observed density of the universe is 2.1 * 10**-29 kilograms per cubic meter. From here to Alpha Centauri is about 4.5 lightyears, and each lightyear is 9.5 * 10**15 meters.
So we're looking at a total distance of about 4*10**16m to Alpha Centauri. Multiply that by the cross-sectional area of our pipe (.6m) and you get... 2.4 * 10**16m**3 of volume.
Multiply that by the observed density of the universe and you get...
5 * 10**-13 kilograms.
Yeah. Like I said. Considerably less than a kilogram.
Your post shows a severe lack of understanding about space. One, it's freaking cold. Two, once you get past Saturn you can pretty much write off solar flares and activity. Three, sure, there are energetic cosmic rays--but they're here on Earth, too, so Earth's no better off. (No, our atmosphere doesn't protect us in any substantial way from cosmic rays.)
If you were to stand on Pluto and turn on a cell phone, the radio signal from your cell phone would be the brightest electromagnetic signal in the sky--by orders of magnitude.
Space is overwhelmingly small, dark and quiet. Yes, there is the occasional bit of matter which can be a real royal pain in the ass... but the odds of a collision are, well, astronomical.
I don't think you understand a damn word of what you just posted, and it astonishes me that you can get a +4 moderation for being totally flipping wrong.
Considering the distance this is realy good for about 10 watts of RF. I would say that the difficulty in hearing the signal is a combination of path loss (well over -130dBm), man made noise, as well as the noise generated by nearby stars and planets.
Of course, if we used computers that lasted this long we'd still be CLI only...
"I bow to no man" - Riddick