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Cassini-Huygens Saturn Orbit Insertion Imminent

Anonymous Explorer writes "Fresh off of its fly-by with the Saturnian satellite Phoebe, the Cassini-Huygens craft is set for Saturn Orbit Insertion on June 30, 2004. Cassini-Huygens has a planned four year mission ahead for Saturn and its many moons. With 450 watts of power for the electronics, this mission has plenty enough horses to run the stretch with plenty-o-pep to spare. Thanks to all that power, and the plethora of electronics on Cassini and the Huygens probe, we can now hear sounds from Saturn. Pretty cool stuff! Festivities are scheduled to begin on June 29th with a broadcast of Cassini Saturn Orbit Insertion Press Conference on Nasa TV. SOI [PDF link] will occur after Cassini fires its main engine for 96 minutes, in order to slow down and be grabbed by the pull of Saturn. As always we extend an invitation to everyone to join #cassini on irc.freenode.net and help us celebrate this historic mission."

66 of 205 comments (clear)

  1. 450 watts? by sirboxalot · · Score: 5, Funny

    I have the same amount of power in my computer's power supply. Something seems fundamentally wrong with that.

    1. Re:450 watts? by umrgregg · · Score: 3, Funny

      Damnit! When I sent in my fabrication designs I told them that they needed to run at least 1.21 gigawatts through the flux capacitor to uh... Well, that's... Nevermind.

      --
      NMG
    2. Re:450 watts? by phorm · · Score: 3, Informative

      I searched through the various articles trying to find that number, but no go. Maybe they're missing a zero... or perhaps 450W is actually a lot on a system that is likely drawing continuous power off a solar panel/battery.

      Considering the computer power needed to go to the moon, it's not likely that this thing needs an 3.2Ghz processor and GeForce :-)

      My Epia-M is plugged in taking about less than 30W of power (including HDD and DVD-ROM)... so really the equivilent of an efficient 1Ghz processor wouldn't need anything near your desktop machine's draw.

    3. Re:450 watts? by falzer · · Score: 5, Funny

      > Something seems fundamentally wrong with that.

      Like watt?

    4. Re:450 watts? by Fouquet · · Score: 5, Informative

      That's a bit low, but not too far off. Cassini uses 3 RTG power sources to generate the ~700-800 W necessary for the science instruments. Solar cells are not practical at that distance.

      This PDF file details the power supply situation on the spacecraft.

      It's pretty remarkable how little power spacecraft like this consume (and I'm pretty sure that Cassini is the most power hungry of the 'outer-solarsystem' probes NASA has launched).

    5. Re:450 watts? by Rei · · Score: 4, Interesting

      Cassini is powered by the heat of decay of plutonium creating a variation in temperature across a junction of two different metals, which creates electric power (thermoelectrics). It's called an RTG: Radioisotope Thermoelectric Generator. They're not very efficient, but you try carrying a pebble bed reactor into space and operating it by long-distance remote control in zero g..... ;)

      --
      I'm an owl exterminator!
    6. Re:450 watts? by Rei · · Score: 4, Informative

      RTGs decrease in power production over time (since we're dealing with half lifes here). It has three RTGs which, initially, produced 285 watts of power each. With a half life of 87 years for Pu238, they should be somewhere around 250 watts each currently, so that sounds reasonable...

      --
      I'm an owl exterminator!
  2. Not even 0.5kilowatts.. by Anonymous Coward · · Score: 4, Interesting

    ..for transmitting from millions of miles away and some HAMs are using 10 kilowatts upwards just for transmitting earth-to-earth!

    1. Re:Not even 0.5kilowatts.. by Anonymous Coward · · Score: 2, Informative

      Well, yeah. Most HAMs don't have dish antennae with diameters measurable in friggin miles...

    2. Re:Not even 0.5kilowatts.. by jandrese · · Score: 4, Informative

      On the other hand, it's not like your average HAM has the Deep Space Network at his disposal. 70m antennas are bigger that you might expect.

      --

      I read the internet for the articles.
    3. Re:Not even 0.5kilowatts.. by CausticPuppy · · Score: 4, Informative

      Yeah but it's directional signal coming from the probe. 0.5 kilowatts of narrow-beam signal goes a lot farther than 10 kilowatts broadcasted from an omnidirectional antenna. But you need dishes at both ends, and they have to be aligned correctly.

      I'm sure I'm not using the correct terminology (in case HAM radio experts are reading this) but that is the gist of it.

      --
      -CausticPuppy "Of all the people I know, you're certainly one of them." -Somebody I don't know
    4. Re:Not even 0.5kilowatts.. by nyrk · · Score: 2, Informative

      for transmitting from millions of miles away and some HAMs are using 10 kilowatts upwards just for transmitting earth-to-earth!

      Some, but it is considered very bad form to use more power than necessary. Transmitting across the ground is very different than transmitting through the space. Line of sight drastically reduces the ammount of power you need, as well as using directional antenas.

    5. Re:Not even 0.5kilowatts.. by mschiller · · Score: 2, Informative
      I should hope NO U.S. Ham is using 10 Kilowatts since we are limited to 1.5 KW output power. Now we won't talk about the Effective Radiated Power, due to the gain of the antenna's used.

      1. http://web.wt.net/~w5un/mba2003.jpg
    6. Re:Not even 0.5kilowatts.. by Auntie+Virus · · Score: 2, Funny

      I started building one, but the friggin neighbors complained again...

      --
      Why yes, I *AM* new here. Why?
    7. Re:Not even 0.5kilowatts.. by Tenebrious1 · · Score: 5, Funny

      70m antennas are bigger that you might expect.

      What, like 75 meters?


      --
      -- If god wanted me to have a sig, he'd have given me a sense of humor.
  3. Victory of SCIENCE over ECOIDIOLOGY by vi+(editor) · · Score: 3, Interesting

    Remember when Greenpeace and other eco-idiologists wanted to abort the Hygens-Cassini mission due to the Plutonium batteries because they might drop back on earth and contain TEH EVIL RADIOACTIVE PLUTONIUM which would kill seals and cute little children ?
    Lucky the officials at NASA and ESA weren't that stupid and fought off this attack.
    The tremendous success of this mission illustrates how these 21th century idiologists are could stiffle science and cause harm for the whole world.
    It makes me wonder if we could get this done today or in year with the eco rising to power in Europe and perhaps US after the elections, too.

    1. Re:Victory of SCIENCE over ECOIDIOLOGY by EvilTwinSkippy · · Score: 5, Insightful
      Airborne plutonium dust is nothing to sniff at. Plutonium is harmless as a solid, but in dust form it's very toxic. Of course, so are the vapors from the rocket's propellent tanks, just about every combusted plastic and rubber compound on the spacecraft, and all the vaporized metal.

      Yes, the greenies were making a mountain out of a molehill. Nuclear powered satellites have been launched for years, and the reactors are specifically designed to survive the destruction of the spacecraft.

      The problem is that we live in a world that is only willing to offer 30 seconds of attention about any subject at a time.

      --
      "Learning is not compulsory... neither is survival."
      --Dr.W.Edwards Deming
    2. Re:Victory of SCIENCE over ECOIDIOLOGY by strictnein · · Score: 3, Insightful

      The far left bases their decisions and opinions on just as much "science" as the far right does. To the far left, nature and humanity is god. To the far right, God is god.

      Take your pick.

    3. Re:Victory of SCIENCE over ECOIDIOLOGY by Mz6 · · Score: 4, Funny
      "The problem is that we live in a world that is only willing to offer 30 seconds of attention about any subject at a time."

      What are you talking about? It's not like the entire World has ADD or some... Hey, what's that shiny thing over there?

      --
      Hmmm.
    4. Re:Victory of SCIENCE over ECOIDIOLOGY by EvilTwinSkippy · · Score: 3, Funny
      Where do we have to go now to enjoy a nice clean refreshing vacuum?

      I dunno, the appliance section of [insert retail store]?

      --
      "Learning is not compulsory... neither is survival."
      --Dr.W.Edwards Deming
    5. Re:Victory of SCIENCE over ECOIDIOLOGY by joehoya · · Score: 5, Informative

      Lots of people are saying that Cassini uses a nuclear reactor... this is not the case as Cassini actually uses 3 Radioisotope Thermoelectric Generators (RTG). RTGs are different from reactors in that they are much simpler devices which produce electricity directly from the decay of radioactive material, in this case PU-238. Reactors on the other hand produce power from heat generated by a controlled nuclear chain-reaction.

    6. Re:Victory of SCIENCE over ECOIDIOLOGY by Rasta+Prefect · · Score: 3, Informative
      If it ticks like a clock, and keeps time like a clock, it's a clock. If it harnesses energy from the decay of nuclear elements, and it does so by converting heat to electricity, it's a Nuclear reactor.

      There are some very significant differences. A Nuclear reactor involves an induced chain reaction. This is just harnessing energy from passive decay. RTG's last a lot longer, but produce less power.

      --
      Why?
  4. Horses? by birdwax2k · · Score: 2, Funny

    ...this mission has plenty enough horses to run the stretch with plenty-o-pep to spare.

    Lets hope none of them are named Smarty Jones...

  5. Slashdot NASA Early by EvilTwinSkippy · · Score: 2, Funny

    Beat the rush.

    --
    "Learning is not compulsory... neither is survival."
    --Dr.W.Edwards Deming
  6. I Wonder... by grunt107 · · Score: 5, Funny

    Do the rings make the same noise represented on the Star Trek Voyager intro?

    1. Re:I Wonder... by ebh · · Score: 3, Funny

      I suspect it's a few clanking and crunching sounds followed by static...

  7. After this insertion... by teamhasnoi · · Score: 5, Funny
    on to Uranus!


    Here, I'll help you out.

    -1, Troll.

  8. sounds? by rgf71 · · Score: 2, Funny

    I'd much rather hear the sounds of Saturn than the sounds of Uranus.

    Sorry. Had to do it.

  9. Insertion Imminent by Timesprout · · Score: 4, Funny

    Alas the only other time geeks encounter this situation is when they plug in a new video card.

    --
    Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
    What truth?
    There is no dupe
    1. Re:Insertion Imminent by Fishstick · · Score: 2, Funny

      Scientists renamed Uranus in 2024 in order to finally stop all those stupid jokes...

      what did they name it?

      Urectum!</farnsworth>

      --

      There is much cruelty in the universe, John.
      Yeah, we seem to have the tour map.

  10. Sounds from Saturn? by IGnatius+T+Foobar · · Score: 4, Funny

    Hearing sounds from Saturn is nothing new. My 1997 SL1 (like most old Saturns) is VERY noisy ... you can hear it coming from a mile away. Step on the gas and it sounds like the power steering pump is going to pop through the hood.

    --
    Tired of FB/Google censorship? Visit UNCENSORED!
  11. I hope it takes photos by WormholeFiend · · Score: 2, Interesting

    I want to see photos of the rings from inside (the rim? the gap?)...

    BTW, how thick are the rings at the point where the probe is passing through them? How long will it take to clear that space?

    1. Re:I hope it takes photos by Mz6 · · Score: 3, Informative

      I can't answer for the thickness of the rings, but it was mentioned in a few of the articles that NASA is trying to stay as far away from the rings as possible. The closest approach will be from above the rings and the rest of the photographs will be taken from the top of the rings. Other than that, they consider them a collision hazard...

      --
      Hmmm.
    2. Re:I hope it takes photos by CausticPuppy · · Score: 2, Informative

      yea but isnt the probe supposed to fly through a gap in the rings? it'd be great to get a photo taken "at level".

      It is flying through a visible gap, and it's an area that seems to be clear of debris according to all the analysis done so far. But it could just be that the debris is so sparse that it's not visible.
      The entry point is actually well outside the visible rings, but there is another very faint ring (G ring) even farther out.

      NASA realized this during the design phase, which is why they are rotating the spacecraft around so that the dish of its high gain antenna will provide some protection against small rocks while it passes through the ring plane. Seems like if the high gain antenna is damaged, then they have other problems though! I'm thinking it was designed with this purpose in mind, at least for protection against particles under a certain size.

      --
      -CausticPuppy "Of all the people I know, you're certainly one of them." -Somebody I don't know
  12. Sound in space? by Anonymous Coward · · Score: 2, Interesting

    How did they get sound? There is no sound in space (since it requires a medium like the air)... My guess is that the frequency of these "sounds" is close to that of the radiation being measured... Does anyone have the complete information on this?

    1. Re:Sound in space? by lockefire · · Score: 3, Informative

      The Huygens probe will be recording the sounds of Titan (which has an atmosphere).

    2. Re:Sound in space? by Vireo · · Score: 2, Informative

      Simply reading the related article tells us that Cassini records the radio emission from the interaction between charged particles and Saturn's magnetic field (in order to measure its rotation rate). These radio waves are in the range of 50 to 500 kHz. The 100-300 kHz band was shifted to the audible 0-3 kHz band to produce the sounds.

  13. Re:Sounds of Martian Life?!! by EvilTwinSkippy · · Score: 4, Funny
    Hey, Americans have a hard enough time finding Canada on a map. Other planets are WAY beyond that.

    /Yes, I'm hitting on my own gang

    --
    "Learning is not compulsory... neither is survival."
    --Dr.W.Edwards Deming
  14. This is from NASA's page by Anonymous Coward · · Score: 3, Informative

    The rings of Saturn have puzzled astronomers ever since they were discovered by Galileo in 1610, during the first telescopic observations of the night sky. The puzzles have only increased since Voyagers 1 and 2 imaged the ring system extensively in 1980 and 1981. In addition to the images, several Voyager instruments observed occultations of the ring system with radial resolution as fine as 100 meters. The rings have been given letter names in the order of their discovery. The main rings are, working outward from the planet, known as C, B, and A. The Cassini Division is the largest gap in the rings and separates Rings B and A. In addition a number of fainter rings have been discovered more recently. The D Ring is exceedingly faint and closest to the planet. The F Ring is a narrow feature just outside the A Ring. Beyond that are two far fainter rings named G and E. The particles in Saturn's rings are composed primarily of water ice and range from microns to meters in size. The rings show a tremendous amount of structure on all scales; some of this structure is related to gravitational perturbations by Saturn's many moons, but much of it remains unexplained.
    linky

  15. Pheobe as a source of ice by bcrowell · · Score: 4, Interesting

    People theorizing about asteroid mining in the past had talked about complicated ways of getting ice out of the rare ice-bearing asteroids. Now that we know Phoebe is icy, I wonder if it ends up being the most practical place in the solar system to get ice. Although it's in the outer solar system, which is inconvenient, that's not necessarily such a big deal with solar-powered ion drive propulsion (as demonstrated by NASA already), which theoretically allows you to send anything into any orbit without paying for energy.

    1. Re:Pheobe as a source of ice by EvilTwinSkippy · · Score: 2, Insightful

      Solar power doesn't provide a lot of energy in deep space. The sun out that far look like a really bright star. That why Cassini needed a nuclear reactor.

      --
      "Learning is not compulsory... neither is survival."
      --Dr.W.Edwards Deming
    2. Re:Pheobe as a source of ice by Neil+Watson · · Score: 4, Informative

      Cassini does NOT use a nuclear reactor. It uses Radioisotope Thermoelectric Generators. Please do no feed misinformation to the nuclear ignorant torch burning masses.

    3. Re:Pheobe as a source of ice by bcrowell · · Score: 2, Informative
      Solar power doesn't provide a lot of energy in deep space.
      Solar-powered ion drives don't require a lot of power; they use low thrust over long periods of time. Check out this link for an example. Note that the name of the craft is "Deep Space 1." It went to the asteroid belt, but even if it went out as far as the orbit of Saturn, it would just have to operate at lower thrust.

      That why Cassini needed a nuclear reactor.
      Cassini doesn't have a nuclear reactor, it has a radioactive source that provides energy by passive heating. (A reactor uses a chain reaction.)

    4. Re:Pheobe as a source of ice by Neil+Watson · · Score: 2, Insightful
      Radioisotope Thermoelectric Generators convert the heat of naturally decaying nuclear material directly into electricity.

      Fission reactors typically control a chain reaction and use the heat to create steam that turns a generator. That generator produces the electricity.

      Yes, at an atomic level the processes are similar (or even the same) but it is important to note the differences. The word nuclear is often maligned due to lack of understanding.

    5. Re:Pheobe as a source of ice by Idarubicin · · Score: 3, Informative
      People theorizing about asteroid mining in the past had talked about complicated ways of getting ice out of the rare ice-bearing asteroids. Now that we know Phoebe is icy, I wonder if it ends up being the most practical place in the solar system to get ice.

      A variant of this idea was explored by Isaac Asimov way back in the novella, The Martian Way (Galaxy Science Fiction, November 1952; subsequently republished in several collections).

      The characters in the novel propose capturing chunks of ice from Saturn's ring system. We don't need to grab a whole moon--there are cubic-mile-sized chunks of ice in the rings. They might be a bit more manageable to manoeuvre. There are lots to choose from, too.

      --
      ~Idarubicin
  16. Ah, but did it generate the 450? by DumbSwede · · Score: 4, Insightful
    450 may not sound like a lot, until you have to generate it for yourself years on end.

    Your little computer is a lot bigger if you include the size of the Power Station it is attached to through a long peice of wire.

    Someone should calculate how the amount of coal or oil that would be needed to provide power for Cassini if it weren't nuclear. Or the size of solar cells needed at that distance from the sun (and their wieight).

    1. Re:Ah, but did it generate the 450? by EvilTwinSkippy · · Score: 4, Informative
      That's pretty easy to do. Look up the enthalpy of combustion for fuel oil and coal. Any good thermodynamic textbook will have both. The unit for enthalpy is KJ/g (Kilojoules per gram of fuel.) A watt is 1 joule per second. (Isn't metric lovely?)

      I googled around and found some stats from the power industry as "energy density of fossil fuel"

      Energy density of Fuel Oil: 42.5 MJ/Kg
      Energy density of Anthracite Coal: 31.4 MJ/Kg

      MJ/Kg is Mega (million) joules per Kilogram. Our power unit provides 450 watts, thus uses 0.00045 MJ/s. A day's worth of power is 0.00045 MJ/s 3600 s/hour * 24 hours/day = 38.9 MJ. (Remember your signifigant digits!)

      To convert that back to weight:
      38.9 MJ/Kg / 42.5 MJ = 0.915 Kg/day of Oil
      38.9 MJ/Kg / 31.4 MJ = 1.23 Kg/day of Coal

      We are in the 7th year of the flight, so:

      0.915 Kg/day * 365.26 days/year * 7 years = 2340 Kg of Oil
      1.23 Kg/day * 365.26 * 7 = 3150 Kg of Coal.

      Plus or minus.

      --
      "Learning is not compulsory... neither is survival."
      --Dr.W.Edwards Deming
    2. Re:Ah, but did it generate the 450? by Rei · · Score: 5, Informative

      I'll do it for gasoline. :)

      Let's assume that Cassini averages needing 700 watts over the course of its lifetime, and lets assume a lifetime of 18 years. That's about 80 MWh of power. Assuming a 40% efficiency diesel engine burning gasoline and oxygen (have to take the O2 with you!)...

      Gasoline has an energy density of 45.8 MJ/kg. Since 2 molecule of gasoline requires about 25 molecules oxygen (O2) to react, you have a molar ratio of 1 mole gasoline to 12.5 moles oxygen. 1 mole of gasoline mass about 114 grams; 12.5 moles of o2 mass about 400 grams. So, your overall energy density is about 10.2 MJ/kg.

      Since we're burning at 40% efficiency, that's about 4.1MJ of energy per kg fuel/oxidizer. 1 joule = 0.0002778 Wh. 4.1MJ/kg = 1.1kWh/kg. 80MWh / 1.1kWh/kg = ~73 metric tons.

      33 kilograms of plutonium suddenly sounds quite appealing, ne? :)

      --
      I'm an owl exterminator!
    3. Re:Ah, but did it generate the 450? by EvilTwinSkippy · · Score: 4, Informative
      Oh yeah, and double all those amounts. That is the theoretical maximum that could be derived from the fuel. In practice, the best we can achieve is 40 percent. (In an industrial setting, small vehicle's like cars are lucky to get 10%).

      So

      2340 Kg / 0.40 = 5850 Kj of oil
      3150 Kg / 0.40 = 7880 Kj of coal

      --
      "Learning is not compulsory... neither is survival."
      --Dr.W.Edwards Deming
    4. Re:Ah, but did it generate the 450? by vlm · · Score: 2, Insightful

      And, you forgot the weight of they oxygen you'd need to carry in order to burn the carbon.

      --
      "Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
    5. Re:Ah, but did it generate the 450? by Idarubicin · · Score: 2, Interesting
      Oh yeah, and double all those amounts. That is the theoretical maximum that could be derived from the fuel. In practice, the best we can achieve is 40 percent.

      Are you sure? That's pretty close to true on earth, where the cold side of a Carnot cycle is going to be at around 300 K. Space, however, is mostly a nice, big, cold blackbody at around 3 kelvin or so (cosmic microwave background.) That should help quite a bit.

      On the other hand, other posters have noted that the mass calculation neglects the oxidizer that would have to be carried. That works out to being three or so times the mass of the fuel, depending on the specific hydrocarbons chosen.

      --
      ~Idarubicin
  17. Sound? What sound? by allanj · · Score: 4, Informative

    The sound they refer to is a frequency-shifted and time-compressed recording of emissions from charged particles in the magnetic field around Saturn. There is no actual "sound" there, as sound requires an athmosphere(sp?) of some sort. There's athmosphere a-plenty on Saturn (most of it IS probably gas, after all), but none near or around the probe.

    --
    Black holes are where God divided by zero
  18. The Song of Saturn At Last! by MooseByte · · Score: 2, Funny

    "Thanks to all that power, and the plethora of electronics on Cassini and the Huygens probe, we can now hear sounds from Saturn."

    Not to mention that giant space phonograph needle they included at the last minute. Now we just have to have it doesn't skip on the Cassini Division.

    (Append witty RIAA reference here.)

  19. Nah, they did it two days early by Limburgher · · Score: 3, Funny

    They figured if they entered orbit two days before the scheduled date, they could avoid attacks by the Saturni insurgents.

    --

    You are not the customer.

  20. Choice: Saturn or Spacewalk by CompressedAir · · Score: 4, Informative

    Today marks an interesting first (at least as far as I have been able to tell): the NASA channel has had to choose which current space activity to put on TV.

    On Wednesday there will be an EVA on the ISS right around the time the Cassini stuff will be happening. Thus, NASA TV had to choose, for the first time, which thing happening in space was more exciting.

    How cool is that? There's actually enough going on up there that one TV channel is not enough!

    Whadya know, the revolution IS televised.

  21. Only 20 Watts... by Jott42 · · Score: 4, Interesting

    The travelling-wave amplifier gives only 20 Watts of output power, which feeds into a 4 meter dish antenna. At 8.4 GHz this gives a gain of about 50 dB. EIRP then at 2 MW. (And a free space loss to Saturnus of about 300 dB....)

  22. Let the orbital insertion begin... by Titchener · · Score: 4, Funny

    wakka-chikka-wakka-chikka "Hello Saturn, I'm Cassini-Huygens. I'm here to repair your plumbing."

  23. Re:ObSpock by Rei · · Score: 4, Informative

    You know, though... when people complain about there being sound in the middle of a big space battle, it always kind of bothers me a bit. Because if you were in space with space ships and missiles blowing up all around you, you *would* hear the sound of explosions as the pressurized gasses and debris from the ship expand in a shock wave travelling at speeds probably quite similar to what we're used to for sound. Sure, it would be all sudden bursts as your spacecraft was hit by the shockwaves, with no prolonged rumbles, but there *would be sound* to a viewer in a spacecraft somewhere.

    And then there's the other things that could possibly cause sound - some of these futurisitic engines are supposed to be powerful ion drives or plasma thrusters, which means that there are very powerful magnetic fields being used and streams of high-velocity charged particles, both of which could possibly have an impact on certain parts of your spacecraft when you get close and make noise. If a beam weapon starts cutting at your ship's hull, your hull is definitely going to make some noise, especially when mechanical components are damaged or gasses start to leak. Etc. There would be lots of sound in a space battle.

    --
    I'm an owl exterminator!
  24. The real reason for the mission by fedork · · Score: 2, Funny

    we all know that _real_ reason for this mission is to deliver a piece of metal to an alien stuck on Titan.

    --
    ...remember good 'ol times when IP used to mean Internet Protocol....
  25. Shorter Slashdot... by Anonymous Coward · · Score: 3, Insightful

    133 comments posted so far. Here's a summary.

    7 off-topic "troll" posts.

    30 posts regarding the nuclear decay powering the craft or simply clarifying the fact that it is not a nuclear reactor.

    96 comments making jokes about the use of the word "insertion" with more than 80 of those comments also mentioning Uranus.

  26. I was an intern at JPL... by IronChef · · Score: 4, Interesting

    Long ago, when I thought I wanted to be an EE, I did a couple of summer internships at JPL. I worked on the Cassini flight computer. My coworkers, especially the lead ASIC designer, were blisteringly smart people. If Cassini fails, it won't be the computer design at least!

    Back then, the project was called "CRAF/Cassini" where CRAF was "Comet Rendezvous/Asteroid Flyby." CRAF was supposed to be the sister ship to Cassini, but it was cut for budgetary reasons. Too bad... with all the design work done how much could it have cost to just build another ship?

    See, we were building this neat computer that would be reused on the next generation of probes, instead of having custom computer hardware for each... but of course it didn't work out that way.

    I was lucky enough to see Cassini (and Galileo) in the Vehicle Assembly Facility. There was an observation deck where you could watch the guys in the clean room building the spacecraft. It was very cool to look down and realize, "that is going to Saturn." Or wherever.

    Cassini is the last of the old school probe designs... a gigantic and expensive. She'll give us a heck of a show.

  27. Re:ObSpock by earthforce_1 · · Score: 2, Insightful

    You would hear sounds inside the spacecraft for sure - in fact, one of the biggest complaints about life on the ISS is noise from all the equipment that is operating, it is very difficult to sleep through all the fans, pumps, and various apparatus turning on and off 24/7.

    But from outside, you wouldn't hear anything, unless electrical interference from the ship's system or natural sources was being picked up by your space suit radio. What is interesting, is that astronouts can communicate without radios if they touch their helmets together, as the helmet itself will carry sound.

    Even a nuclear blast in space wouldn't produce much of anything in the way of sound, as the only "atmosphere" would come from the vaporized bomb itself, and would be quite tenuous unless you were right beside it, when the thing went off. And you would of course be vaporized long before you could sense it.

    Most of the explosion effects would be thermal energy and radiation pressure. Particle and directed energy weapons (lasers or phasers?) would not produce any sound at all.

    The only way to get any sound at all floating about in a space battle, is perhaps if you were right beside a ship was ripped apart and lost pressurization. Then you would (very briefly) have a tenuous atmosphere to carry whispers of the ship's destruction. You might have better luck hearing something if you press your helmet to the hull of a vessel.

    --
    My rights don't need management.
  28. Actually, many Hams get by fine just a few watts by MooseByte · · Score: 3, Interesting

    "some HAMs are using 10 kilowatts upwards just for transmitting earth-to-earth!"

    Actually, ignoring the 1.5KW max Ham radio ops are legally bound to, most Ham operators operate in the 100 watt range (in the HF freqs == "shortwave"), and there's a dedicated core of low-power enthusiasts who communicate around the world on 5 watts, 1 watt or even a few hundred milliwatts. (The microwatt crew even come out during favorable solar conditions).

    Check out these guys for a starting point.

    It varies by spectrum of course (VHF/HF/etc.) but I've personally worked every continent with less than 5 watts using just a homemade wire antenna, no fancy NSA-like array of metal high in the air.

    Antarctica was the most fun - Russian op down there at their research station. Darn neatstuff!

  29. Re:I can't wait... by GedConk · · Score: 2, Funny

    Talking about Venus, I heard she's HOT ! ;)

  30. Cassini's Real Interaction with the Rings by Rhodnius · · Score: 4, Interesting

    In a nutshell, here's how Cassini will interact with the rings during the orbital insertion.

    Saturn right now is tilted, so that the south/"bottom" side of its rings is facing towards the Sun and Earth. Hence, Cassini is approaching Saturn from "underneath" as we see it from Earth. The orbit insertion requires Cassini to pass through the equatorial/ring plane south-to-north as it approaches the planet. It will fire its rocket while on the north side of the rings, and then coast back to the south side on its way back out.

    Now, how is Cassini doing that safely? It's doing so by going through the ring plane where there are no rings. It could be thought of as a "gap", but Cassini really isn't anywhere near the rings when it crosses them. The crossing points are far outside the main mass of the ring system.

    A rough analogy is this. Suppose you lived in Alaska, and had a sailboat named Cassini. Now suppose you had to sail from Alaska to Mexico without bumping into anything. Naturally, you'd pass between Hawaii and the continental US. That's a rough analogue to what's going on at Saturn - the main mass of the rings is like the continental US landmass (and there's a few small intra-ring gaps like the Mississippi River), while there's a few small outside rings sort of like the Hawaiian islands.

    Would it be possible that your sailboat bumped into a rock or debris or something that we didn't know was there? Yes. Is that possibility remote enough that it makes for the safest course to your destination? Also yes.

  31. Re:Sounds of Martian Life?!! by WormholeFiend · · Score: 2, Informative

    Actually, canada is an aboriginal word that means village.