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Space

Cassini Begins Jupiter Flyby 52

Posted by Hemos from the drive-by-camera-shooting dept.
syrinx writes "Cassini has started its flyby of Jupiter. It will continue to be near Jupiter until March, when it will begin its journey towards Saturn, hopefully reaching it in 2004."
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Cassini Begins Jupiter Flyby More

Cassini Begins Jupiter Flyby

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  • Re:Why Jupiter? (Score:3)

    by Cef ( 28324 ) on Monday January 01, 2001 @01:45PM (#538196)
    There is also a large amount of elements that would be very useful, mainly as propellants and chemicals for orbital factories. Many of these chemicals are plentiful on Jupiter and Saturn, unlike here. There is also a lot more of Jupiter/Saturn available.

    Jupiter also throws out some of the most devastating electromagnetic radiation, and if humans or human-made equipment is to survive under those sort of conditions, we need to research it!

    What I want to know is when we are sending stuff to the asteroid belt to get some idea of the mineral composition that these asteroids have. They are our closest 'space-bourne' mineral source, and the least likely to be missed (as compared to the mountains on Mars, or some other feature).
  • when do we land on Europa??

    Well, according to 2010, we have to wait for the Chinese to claim this convenient refueling station and discover life there. They are currently preparing for a second (unmanned) test flight of their Shenzhou spacecraft, so there's still hope...

    As for the pictures, why don't you have a look there [nasa.gov]?

  • See, there are several ways to go to the moon. There is the cheap fast way, which is what we did, which is you start with a great big rocket and throw every bit of it away as you use it up until you splash down damn near buck naked with a rock in your hand in the Pacific as the last of your heat shield dissolves around you. Definitely uses the least amount of material, problem is it doesn't leave any infrastructure. Next time you want to go you're right back where you started.

    Or you could build a platform in Low Earth Orbit, move provisions to it, set up a much more efficient orbital transfer system with ships designed for deep space, maybe have another smaller platform in lunar orbit, and set up what amounts to regular service between the two planets. Very expensive, especially at first, but ultimately much cheaper per pound if your goal is to ferry tonnage onto lunar soil in order to build a base.

    Colonization wasn't the game, obviously. Impressing the rooshians was. And once we impressed the rooshians as cheaply as possible we picked up our toys and came home.

    I guess we can poke a little blame JFK's way for setting such a ludicrous timetable, but then he too was driven by the cold war. We could have had colonization as seen in the movie 2001 by now, but we didn't go for it. And that's the rest of the story.

  • You could just go to the web site and get a rt update of it's speed.

    http://www.jpl.nasa.gov/cassini/english/where/ [nasa.gov]
  • If the Cassini is powered by an ion drive,

    It is not.

    and the atmosphere of Jupiter is predominantly methane gas,

    I don't think it is; rather hydrogen, but I could be wrong.

    if the two were to come close enough to each other,

    Cassini has passed the point of closest approach. 10million kilometers, give or take.

    where would be the best place be to view the fireworks from?

    What fireworks?

    I often wonder how the atmosphere is so stabilized in it's current state, that it maintains such well divided regions of different types of gas clouds. It changes with the day, but the large spots have never moved.

    Well, you're not the only one. I think the meteorology of Jupiter is one of the mysteries of planetology. Think of the Great Red Spot, twice as big as Earth, has existed since we are able to point telescopes at planets... Wouldn't it be nice if our cyclones persisted for centuries?

  • Putting stuff from Earth to Moon costs the same amount of energy as putting it in parking orbit and then sending it to the Moon. So unless you bring materials from somewhere else (asteroids?), those intermediate orbiting stations would be useless. The reason astronauts came back in a reentry capsule is that their speed was too high and it would take too much fuel to decelerate to Earth orbit velocities. They would have had to lug that fuel with them all the way. Not very feasible, even if there was an orbiting station. Putting stuff on the Moon in general is not that expensive, if you don't want to bring it back, like parts for a base for example. My guess is, they could have set up a base on the Moon instead of ISS for about the same amount of money.

  • Re:Does anyone else know how fast Cassini is? (Score:3)

    by Soft ( 266615 ) on Monday January 01, 2001 @01:06PM (#538202)
    how far the distance between Jupiter and Saturn

    It changes all the time, of course...

    Right now, according to this Solar System Simulator image [nasa.gov], Cassini is about 630million kilometers away from Saturn (which amounts to 390million miles, or 4.2AUs).

    As for the speed, it also changes all the time, you know, trading kinetic energy for potential energy, Kepler's laws, all that stuff. According to this page [nasa.gov], it is moving at about 47,500kilometers an hour, with respect to the Sun, I assume (29,500mph, 13km/s), but it will slow down a lot as it gets farther from Jupiter and the Sun.

  • Even if we discovered life on Europa it most likely wouldn't be sentient, much less intelligent. It's all very interesting but as long as there are better uses for the money, (feeding the poor or lowering taxes not just moon bases) we shouldn't be throwing it away.

    (Insert Queen Isabella / Columbus analogy here)

  • going past jupiter?? cassini?
    that's inconceivable!
  • Why do these news stories always begin with the project cost

    Probably because the paying public wants to know. Of course, with Cassini, you've got the fact that it is the single most expensive science mission that NASA's ever launched. $3.2 billion is probably on the low end of the total cost estimates.

    The cost is actually Cassini's single biggest problem. While the data that it will report back from Saturn is certainly valuable -- the only missions that flew out there were Pioneer 11 and the Voyagers, all of which were flyby missions -- it is debatable whether it should have been that expensive.

    Cassini is, after all, the last of the Battlestar Galactica spacecraft. Newer missions are much smaller in scope, and, consequently, much cheaper. Even the (cancelled) Pluto-Kuiper Express mission was only to cost something like $700 million.

    The reason why you don't want to launch such expensive, all-in-one-basket missions is that if something goes wrong, you've lost everything. When I heard about the reaction-wheel problems it recently had, I was very worried about what could happen to the mission. Fortunately, this has been resolved.

  • No monolith?
    You must be mistaken. I am 100% sure that if the moon was scanned with magnetometers, THEY WOULD HAVE found a monolith. IT HAS TO BE THERE. I SAW IT ON THE MOVIE, SO IT HAS TO BE THERE.

    There is a monolith... there is a monolith... there is a...

    "My God, it's full of cars" - Dave Bowman's reaction when he received a Hot Wheels collector's set at the age of 6.

  • Some of these images are breath-takingly beautiful [nasa.gov]. Does anybody know is even higher resolution versions of these images exist? I would love to spit some of these images out on my wide-format printer for my wall!

    Or, really is bandwidth so narrow or is the CCD so small that they only shuttle back ~1MB images from the Cassini?

    -AP

  • I thought they were going to ditch Cassini into Jupiter's atmosphere. Or on Io. Or Europa. All of a sudden they're using Jupiter as a gravity slingshot to get Cassini to Saturn. What happened?
  • If the Cassini is powered by an ion drive

    It is not.

    What's this [nasa.gov]? Would that be Plutonium ion degeneration powering all of the RTG's

    Okay so it's not your average Star Trekkin' warp factor niner, but it is a step in the right direction.

    and the atmosphere of Jupiter is predominantly methane gas,

    I don't think it is; rather hydrogen, but I could be wrong.

    3000 (CH4) parts per million in a dominant 89% Hydrogen atmosphere isn't predominant as stated before.

    if the two were to come close enough to each other,

    Cassini has passed the point of closest approach. 10 million kilometers, give or take.

    the key prerogative being if

    where would be the best place be to view the fireworks from?

    What fireworks?

    I won't even begin to explain. Notice the Heading. Dumb Question. Capped off with a nice little fuzzy "I wonder" at the end.

    Wouldn't it be nice if our cyclones persisted for centuries?

    No


    .
  • Let me get this straight! Solar winds "sound" like "whales in ecstasy?" That's fucking ridiculous... Hehehe

    I bet they sound better than your winds.

    My winds sound like Bill the Cat - "Thpppt".

  • They are "ditching" a probe, named Huigens, on Titan. One of Saturns moons
  • They're all quite pretty.


    You like science?
  • OK, it was funny, but actually, the guy's name was Vizzini.
  • Let me get this straight! Solar winds "sound" like "whales in ecstasy?" That's fucking ridiculous... Hehehe
  • Why would we want to go get rocks from the asteroid belt? There seems to be an awful lot of this planet still lying around...
    --
    If the good lord had meant me to live in Los Angeles
  • You know - that word - I do not think it mean what you think it mean
    --
    If the good lord had meant me to live in Los Angeles
  • I think that is really neat I wonder if the Jupiter thing will go over as well as the Mars deal?
  • How can you be first post yet be anonymous. you suck man. when I'm first post I'll tell the world.
  • Cassini Begins Jupiter Flyby

    As the article states, Cassini has passed the point of closest approach two days ago. Which means it is currently receding away from Jupiter, past mid-flyby, on its way to Saturn.

    Yes, there had been some problems with the maneuvering systems, which had halted observations for a few days, but a lot of science has already been done. Indeed, having two spacecraft in the vicinity of the same planet is quite an opportunity, and had not happened before except in the case of Mars (and the Earth, of course).

    Also, AFAIK, this is only the fourth spacecraft in history to perform a Jupiter gravity assist (the first three being Voyager 1 and 2, and Ulysses). Far too few, IMO. The Discovery doesn't count.

  • Comment removed based on user account deletion
  • #include <iostream.h>
    int distanceBetweenEarthAndJupiter = prettyDamnFar;
    int Time = 2004 - 2001;

    int main()
    {
    cout<<distanceBetweenEarthAndJupiter/Time&lt ;<endl;
    return 0;
    }

  • "I get 3250 miles to the gallon on this hog... traded it for the wagon."

    As long as it takes for trips to Jupiter and Saturn, I'm beginning to realize that I will never see the day that a human walks on any of either planet's moons (39 between them, right?). Landing on the moon was great, but that was before my time. No one's walked on Mars yet, so hopefully I'll see that. No one will ever walk on Jupiter, I realize this. Com'on NASA, all I want for Christmas is to hear about some John Smith walking on the moon ... yeah that moon about 200 million miles away. Talk about a leap for mankind...

    What exactly is accomplished with a planet "flyby" anyway?

  • If the Cassini is powered by an ion drive, and the atmosphere of Jupiter is predominantly methane gas, if the two were to come close enough to each other, where would be the best place be to view the fireworks from?

    Nice pics, same as last time. More new ones! Though the resolution is prime. I often wonder how the atmosphere is so stabilized in it's current state, that it maintains such well divided regions of different types of gas clouds. It changes with the day, but the large spots have never moved.


    .
  • Jupiter is completely unhabitable! Why invest millions into studying it when we won't find a use in it?

    Well, Cassini is currently using Jupiter, to propel it towards Saturn! OK, you'll answer that Saturn is unhabitable too, but:

    • both Jupiter and Saturn have large, planet-sized moons, which may one day be colonized;
    • life may exist there or on the moons (subsurface oceans on Europa and possibly Ganymede and Callisto, an atmosphere and hydrocarbons around Titan, not to mention the possibility of "aerial" life in the atmospheres of the gas giants themselves);
    • the planets are interesting in themselves, for the sake of science; Cassini's worth a few billion dollars, negligible compared to the useless space station's skyrocketing costs;
    • setting up bases on the Moon and Mars is good too, but we unfortunately lack the political will.

    Is that enough?

  • As long as it takes for trips to Jupiter and Saturn, I'm beginning to realize that I will never see the day that a human walks on any of either planet's moons

    Don't lose all hope yet... Between all those start-ups trying to democratize cheap access to space, growing interest about possible life on Europa, and the ever-growing life expectancy, there might be a little chance?

    (39 between them, right?).

    About that. Maybe a bit more, some have been discovered recently. And that doesn't account for the rings, of course...

    Landing on the moon was great, but that was before my time. No one's walked on Mars yet, so hopefully I'll see that.

    AOL.

    No one will ever walk on Jupiter, I realize this.

    Hot hydrogen balloons, anyone? Saw that in one of Clarke's stories...

    Com'on NASA, all I want for Christmas is to hear about some John Smith walking on the moon ...

    No. What I want for Christmas is to hear about someone settling on the Moon. Alive, of course. And preferably myself.

    yeah that moon about 200 million miles away. Talk about a leap for mankind...

    About 240,000 actually. Which makes it all the worse... Do you realize that no human has gone farther than a few hundred kilometers from the surface of the Earth for almost 30years?!

    What exactly is accomplished with a planet "flyby" anyway?

    Better that than nothing. Gives some opportunities for remote observations, and a little push for a longer journey...

  • What's this? Would that be Plutonium ion degeneration powering all of the RTG's

    That's a Radioisotope Thermoelectric Generator. It is a device that produces electricity by using the heat which the radioactive decay of the plutonium inside yields. It is used as a power source for the instruments and electronics aboard the spacecraft.

    An ion drive, on the other hand, is a propulsion system in which propellant is ionized (that is, the atoms or molecules gain or lose electrons), thus becoming electrically charged so that it can be accelerated at high speed and expelled from the spacecraft. The exhaust speed being much higher than for conventional chemical rockets, the engine is far more efficient. The drawback is that the rate of propellant ionization can't be very high, so the thrust is extremely weak.

    So, you see, an RTG and an ion drive are totally different beasts: one produces power, the other consumes power and converts it to thrust. And it is conceivable to use both in a complementary way, as in having an ion thruster powered by an RTG; a very sensible solution for missions to Jupiter and beyond, IMO.

    (And my apologies if you found my previous reply overly dry...)

  • If the monolith existed it would already been discovered, since the moon was already scanned with high sensivity magnetometers, and that was how it got discovered in the movie.

    Sorry guys, no monolith found :-)

  • why always the cost first? (Score:3)

    by Barbarian ( 9467 ) on Monday January 01, 2001 @01:25PM (#538228)
    Why do these news stories always begin with the project cost (NASA's 3.2 billion dollar spacecraft CASSINI..)? It distracts from any benefits of the project and appears to be designed to get anyone who pays taxes up in arms immediately.

    You don't see this in other reporting: "NASA's Space Shuttle Discover, in which $45 billion has been spent to date, was launched for an uneventful mission from Cape Canaveral).

    So why does the mainstream media seem to think that projects doing real scientific work (Cassini, Galileo, the mars missions, SOHO, TRACE, etc.) are a waste, while the space shuttle, with a maximum working orbit of 320 km is a necessity? IIRC, the cost of Cassini is similar to a couple space shuttle launches.

    I don't mean this comment as flamebait, but, $3.2 billion is a small cost to pay for what we will learn from Cassini. (keep in mind that was spent over something like 20 years, including the long storage time when all launches were scrapped after the Challenger accident). Several spacecraft like Cassini would be a small price to pay, and keep in mind, if, say, ten had been made (Cassini was originally the Mariner Mark III), the cost would have been a lot less then $3.2 billion each.
  • We went to the moon, we got some rocks, we dropped a feather and a bowling ball, then went home. NASA ran away and abandoned the project, what I want to know is why.

    Because the goal of the Apollo project, which was to give the finger to the Soviets, had been reached. Nixon needed money for the Vietnam war, and NASA's budget was one that could be cut off. Plus the fact that it was costly compared to the results it yielded, for the very same reason as above.

    You might want to read Stephen Baxter's "Voyage", featuring an alternative reality in which the US gets on to Mars after the Apollo flights. With a good demonstration of how the political machinery between NASA, the White House, the militaro-industrial complex, etc., works...

    We could easily be taking holidays on the moon, but NASA don't want any more research done into the moon.

    It's not that they don't want that; they do want to go back to the Moon, Mars and wherever you give them money to go with! That's the problem, you see, not only are they not really able to get results on the cheap - by their very nature as an administration, IMO - but Congress won't give it anyway, as it is perceived as being expensive, implies a lot of politics, and so on.

    I WANNA GO TO THE MOON.

    Shall I say "AOL"? Actually, no, I wanna live on the Moon.

  • You are completely correct. I refered back to one of the Astronomy magazines that I originally saw the article about Ion Drives. It came out about a year+ ago. I was convinced that this was what's powering the Cassini. I stand corected. I did read that in experiments, the Ion Drive could top out about 39,000 miles an hour. What that translates to in F/P thrust I have no idea. And the tests have not been fully performed in a weightless environment where the maximum potetial momentum can be reached. The Ion Drive concept is the closest we've come to being able to establish the possibility for travel at the speed of light. It's all Physics from there.


    .
  • Augment last post due to serious misinformation:

    Deep Space I [nasa.gov]

    Ion FAQ [nasa.gov]


    .
  • I understand it's important for the "sake of science", but there are much more pressing concerns right now. From what I understand Cassini isnt studing life on Europa or possible life in the upper atmosphere of Jupiter or Saturn, it's just sort of a big gloryified camera with some instruments attached.

    Even if we discovered life on Europa it most likely wouldn't be sentient, much less intelligent. It's all very interesting but as long as there are better uses for the money, (feeding the poor or lowering taxes not just moon bases) we shouldn't be throwing it away.

  • Re: tada. (Score:3)

    by deglr6328 ( 150198 ) on Monday January 01, 2001 @04:12PM (#538233)
    http://photojournal.jpl.nasa.gov/ [nasa.gov]. pick your planet, then pick a spacecraft observation, then find a pic you like, then click on "more options" and choose your format for a full resolution image. :-D

  • Putting stuff from Earth to Moon costs the same amount of energy as putting it in parking orbit and then sending it to the Moon. So unless you bring materials from somewhere else (asteroids?), those intermediate orbiting stations would be useless. The reason astronauts came back in a reentry capsule is that their speed was too high and it would take too much fuel to decelerate to Earth orbit velocities. They would have had to lug that fuel with them all the way. Not very feasible, even if there was an orbiting station. Putting stuff on the Moon in general is not that expensive, if you don't want to bring it back, like parts for a base for example. My guess is, they could have set up a base on the Moon instead of ISS for about the same amount of money.

    The point about using intermediate bases are that there is then something you don't have to bring all the way to the moon and back. E.g. landing gear for earth could be used only from earth orbit and landing gear for the moon in moon orbit. Even some of the fuel should be possible to transfer in a low cost but long time transfer that uses the moons gravity to assist.

    A moon base would have been better use of money than the ISS though. After all - the purpose of the back side of the moon is to enable astronomy. Just think what could be done with a radio telescope across most of the back of the moon.

  • It's Galileo that's eventually going to be ditched in the Jovian atmosphere. Cassini is a newer probe being sent to do the same kind of missio at Saturn.

    Cassini is taking a longer route than the previious Saturn missions because unlike the Voyager and Pioneer series, it has to arrive at Saturn at a slow enough speed so it can settle into orbit.
  • I did read that in experiments, the Ion Drive could top out about 39,000 miles an hour. What that translates to in F/P thrust I have no idea.

    There is no direct relationship between thrust and top speed, it depends how long you can thrust; in the case of ion drives, it can mean months or years.

    A better way to apprehend things is the rocket equation: if u is the exhaust speed and m0 and m1 the mass of the spacecraft respectively empty and fueled, then an ideal rocket in a vacuum in a weightless environment can change your speed of: Deltav=u.ln(m1/m0).

    And the tests have not been fully performed in a weightless environment where the maximum potetial momentum can be reached.

    Wait, what about Deep Space1 [nasa.gov]? The thing is now on the other side of the solar system, has visited a comet last year, and is on its way to a second, I think. And it has totaled almost two years of thrusting, weeks or months at a time!

    As for traveling at lightspeed, surely it is a step ahead of chemical propulsion, but we still have a long way before we can even approach even fractional lightspeed! Try looking at the rocket equation above; an ion drive typically accelerates its exhaust up to 10-20km/s (compared to less than 5km/s for chemical rockets). To reach a thousandth of lightspeed, in the best case, you'll need over three million times as much fuel as the mass of your spacecraft, which includes the fuel tank, of course. Quite a challenge...

  • I guess "Thpppt" is better than "Ack!" which is the other famous Bill the Cat sound...
  • at least it wasn't "NASA's 3.2 billion dollar orbiting plutonium environmental radiation hazard Cassini"
  • Sorry everybody, those neato pictures from anywhere in space are computer enhanced, just like the chicks in the victoria's secret catalog. No lie. The real colors are thin, pale and lame, just like the chicks in the victoria's secret catalog.
  • the guys name in the movie "The Princess Bride" ?
  • Wait a minute! Cassini is not supposed to be making a Jupiter flyby this year... I thought it was supposed to be the Discovery.

    And Hal 9000 claims to be infalible. HA!
  • Perhaps overly influenced by Arthur C Clarke's tales I'm fascinated by Jupiter. A planet with 4 planet sized moons, which recieve more heat from it than from the sun, a solar system in miniture etc etc.

    ANyway I cant wait to see the pictures, but when do we land on Europa??
  • If it reaches Saturn in 2004 and it's flying by Jupiter just now, then just how far the distance between Jupiter and Saturn
  • We went to the moon, we got some rocks, we dropped a feather and a bowling ball, then went home. NASA ran away and abandoned the project, what I want to know is why. We could easily be taking holidays on the moon, but NASA don't want any more research done into the moon. Russia didn't even bother trying to get there after NASA beat them, they were just in the race for the glory of getting the first pictures back from the moon and putting gary kasparov in a tin can. I WANNA GO TO THE MOON. bye

  • HALDave (Score:1)

    by Anonymous Coward
    All these worlds are yours...except Europa. Attempt no landings there.

  • Official Cassini Homepage! (Score:5)

    by DaneelGiskard ( 222145 ) on Monday January 01, 2001 @12:19PM (#538246) Homepage
    Hi!

    Here is the official Nasa Cassini Homepage [nasa.gov]

    Many nice pictures [nasa.gov] and much more.

    cheers
    mike
  • Funny, 2001 is just about to air on cable TV here...

    Anyway, I heard the mission had been canceled due to the failure to find a Monolith on the Moon (or settle the Moon, for that matter), manufacture reliable gas-core nuclear fission engines, and AIs. And bug-free software, too, but that would definitely not have stopped them, as we all know.

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