Catch up on stories from the past week (and beyond) at the Slashdot story archive

 


Forgot your password?
Close
typodupeerror
×
Space

NEAR to Fly Once More 168

Posted by michael from the this-ain't-no-Mir dept.
david.given writes "Yes, those loons at APL just will not leave the spacecraft in peace. The latest plans are to attempt to fire the thrusters again on Feb 14, 1900UTC (1400EST) and lift off the surface of EROS. If the thrusters work, and the trajectory is correct, and the camera is undamaged, and the communications system holds up, they reckon that they should get some more pictures from about 400m up. What's next? They're going to bring it home?"
This discussion has been archived. No new comments can be posted.

NEAR to Fly Once More More

NEAR to Fly Once More

Comments Filter:

  • APL- East Coast, JPL West Coast (Score:1)

    by Anonymous Coward
    Makes you think huh, despite all this talk about Silicon VAlley, it's really the East Coast that gets the amazing things done.

    East Coast

    NEAR
    AT&T UNIX
    Linux drivers for MWave

    West Coast

    Mars Lander
    Netscape
    NT

    Well, I could go on.

  • Re:fly (Score:1)

    by Anonymous Coward
    just to save everyone the time, this decodes to "Nasa 0wns j00"
  • It really adds that extra realism effect to all those maps and servers that have low gravity set on them!
  • Remember the RC car that you got for Christmas?

    What did you do with it?

    Why you ran it until the batteries were dead of course.

    Until that time, you ran it everywhere it could go...


    Good judgement comes from experience, and experience comes from bad judgement.

  • Or not! (Score:1)

    by Bwah ( 3970 )
    The atari (as I recall) is powered by an 8088. The memory management/bank swapping model used on the 1750A makes intel's segment-offset look like a WONDERFUL DREAM.

    As you fill up your ROM on the 1750 (I'm assuming that your ARE running in expanded mode, with mode that 64k words of ROM) like past 70% or so, cramming all of your code in get HARD. It's not quite as bad as some of the other bank swap memory setups out there, but by modern standards it's an evil way to address 1 megaword of ROM.

    sorry, thus endith my rant ... :-) It's been a long day fighting that damn chip!

  • Well, you'd need a lot more fuel to get the thing back to Earth orbit.

    Naah, just target it for an earth-orbit-crossing asteroid and let it sit there until it gets back... ;)


    Your Working Boy,
    - Otis (LICQ: 85110864)
  • "Hey, great landing. The press is going mad over here. Just for kicks, we've decided to send you back up for another landing." Poor guys will end up hopping all over Mars. At least until something breaks. :)

    That's funny sarcasm guys. I do think it's amazing that they were able to land this thing from millions of miles away and do it successfully. Imagine controling your remote control buggy with a lag time of minutes to hours. Heh, try flying your remote control airplane with the same lag time AND without actually being there to see it do it's thing. Pretty cool stuff they're doing.

    Mike

  • Re:Next (Score:1)

    by trb ( 8509 )
    Next they're going to shoot the retro rockets and try to land it closer to the McDonald's.
  • Nah - the sequence converges... :-)
  • hehehe. TCP/IP seems to have garnered almost as many religious fanatics as Linux.

    Ad Hominem, baby!

  • Didn't they try that one on the moon a while back? (Getting really far out and ramming it at high speed)


    No, but NASA did it with Uranus.

  • Nice idea, but doesn't it double the chance of faliure? I mean, think how stupid you'd look if the asteroid lander failed and your orbiter was still up.. I suppose you could always leave it
    there and send another asteroid lander up instead.

    Hmm. Why not make the orbiter permenant and manned. Ah, yes, I do believe there is a project
    along these lines!
  • Didn't they try that one on the moon a while back? (Getting really far out and ramming it at high speed)
  • NEAR is presently 16 light-minutes away, which is way too far for the TCP/IP limit. The Moon is only 1.5 seconds away (3 second round-trip), so TCP/IP can work.
  • So you're proposing using it as the first asteroid-based observatory. Unfortunately it won't work in this case. Eros is spinning and yawing like a tossed shoe, so the antenna dish rarely points at Earth -- it would be hard to send any images back. Also, the cameras don't have the wonderful stargazing lenses of Hubble, and even if they did they're not on a stable platform so only the brightest objects are briefly visible. And the probe itself won't survive long; three months is the estimate.
  • If you can land a probe on a rock, how about just leaving it there, and use it as a cheap system to get around the solar system at whatever weird orbit the thing is doing?

  • Well, you'd need a lot more fuel to get the thing back to Earth orbit. Presumably a shuttle could go up and get it ... but I am guessing that the need to carry the return-trip fuel out there would make the thing a heck of a lot more expensive (because you'd also need more fuel to carry that additional fuel).

    But it would rock if they could do it.

    Yeah, there's nowhere near enough fuel. I don't have the numbers for Eros, but coming back to Earth from the orbit of Deimos (High Mars Orbit) is about 1.8 km/sec. NEAR's initial fuel supply was only enough for 1.436 km/sec (not counting the reserve). And, that assumes aerobraking in our atmosphere. NEAR has no heat shield -- crispy critter! I have no idea how much fuel it would take, but:

    • NEAR massed about 800 kg at launch.
    • It would have to be using storable bi-propellants, (usually nitrogen tetroxide and hydrazine) which aren't the most powerful fuels available, but don't need cryo-coolers.
    • If it had a heat shield, then NEAR would need a bit more fuel to circularize its orbit after aerobraking. Not too much, say enough for 100 meters/sec.
    • If no heat shield, then NEAR would need loads more fuel to match Earth's orbit. Sure, they could play some gravity deassist games with the Earth and Moon, but that's a lot of velocity to shed. It would still take burns with fuel that NEAR doesn't have.

    Anyway, we really don't want NEAR back. Without any kind of sampling scoop, etc., odds are poor that any Eros dust would still be on its surface by the time we could pick it up. Even less so, if it aerobraked without a heat shield. ;^)

    PS: You're right about the cost of the extra fuel. The rocket equation is an exponential function. A little more starting mass requires lots more fuel for the entire mission.
    --

  • And to think all this from a species made of meat [slashdot.org].


    Unfortunately I can't seem to link to the exact comment of an archived story, but use your browser find for the word meat.

  • Re:Next (Score:1)

    by p3d0 ( 42270 )
    From net/ipv4/tcp_timer.c:
    /* Increase the timeout each time we retransmit. Note that

    * we do not increase the rtt estimate. rto is initialized
    * from rtt, but increases here. Jacobson (SIGCOMM 88) suggests
    * that doubling rto each time is the least we can get away with.
    * In KA9Q, Karn uses this for the first few times, and then
    * goes to quadratic. netBSD doubles, but only goes up to *64,
    * and clamps at 1 to 64 sec afterwards. Note that 120 sec is
    * defined in the protocol as the maximum possible RTT. I guess
    * we'll have to use something other than TCP to talk to the
    * University of Mars.
    *
    * PAWS allows us longer timeouts and large windows, so once
    * implemented ftp to mars will work nicely. We will have to fix
    * the 120 second clamps though!
    */

    --
    Patrick Doyle
  • Well, VGER had to come from somewhere right?

  • Keep in mind that the maximum level of acceleration happens to be directly related to g. If the figures are correct on a different post, the best acceleration you could get from traction is about .0004 m/s^2. It would take a long time to get enough speed to go anywhere.
  • I don't know why they bothered spending so much money to bring back those Russian guys. They were MIR astronauts.
  • So, what did they gain by this landing, besides showing they could do it? And what do they hope to gain by lifting off again?

    I had assumed they were going to study rotational movements (maybe even vibrations, using phase shifts of the transmitter's signal?) when they landed.

    It's cool that they can do stuff like this, and I understand that yet-more-pictures of a rock in space wouldn't be much fun, but I would have thought that even the "bonus science" at the end of the mission would have been better planned.

    --David Burns

  • what's to stop them...?

    I imagine lack of fuel, for one thing...Spacecraft tend to not carry much more fuel than absolutely necessary; NEAR is probably running on fumes right now. The kind of maneuvering they're doing (setting it down and taking off again) take a negligible amount of fuel , compared to changing orbits to rendezvous with Earth again.

  • Tang. And freeze-dried ice-cream, though I have no clue why anyone would *want* to eat that...

  • Right now I think NASA is focusing on the unix method of "do one thing and do it well", with the added requirement of "do it cheaply". This mission was meant to go out to the asteroid and take pictures of it, run spectrographic analysis, etc. Your basic ranged sensing package.

    I'm sure sending some sort of rover/sample return mission to an asteroid can be expected in the relatively near future. It wouldn't be too much different from the Stardust [space.com] mission, which is currently on its way to collect material from the tail of the comet Wild-2 and return it to Earth (in 2006).

    Right now, though, they're just playing with the last bit of functionality from a defunct piece of equipment. Recall the Lunar Prospector [space.com] probe, which they crashed into the moon after its mission had been completed, on the off chance that the plume of debris it kicked up would show signs of water. It's a matter of, "we could leave this floating in space forever, or we could try this one last thing before we abandon it." I have to give them credit; they've done some pretty cool things with spacecraft that weren't meant to do them.

  • Well, this is true. By the time it got near enough that we could pluck it out of space easily, we would have already gone out, grabbed an asteroid, and towed it into low-earth orbit (what the space shuttle travels at) with a craft designed for such an activity (large-scale sample return...yum) for ease of study. Okay, maybe not. But, at any rate, by the time NEAR got back, the only thing it would be useful for is sticking in the Smithsonian.

    There's no reason to bring it home. Better to just use and abuse it where it is. See how much we can do with it before the fuel runs out and the camera gets destroyed. Hmmm....Do we need all four solar panels to run the instrumentation? If we oriented it so that one of them was stuck in the dust, we could scoot along and dig little trenches; see if we kick up anything interesting to take pictures of. (and, in space, *everything* is interesting to take pictures of)

  • Yep...When the Lunar Prospector finished its mission they crashed it [nasa.gov] into the Moon's south pole in an attempt to kick up water vapor that could be observed from earth...They didn't find any, but the chance of finding any was given at about 10%, assuming that there was some there to find. But it was a good try...

  • They used maneuvering thrusters to keep the probe in orbit around Eros until they decided to land it...That's part of the life cycle estimate for an object in orbit around a body; how much fuel are you willing to devote to keeping it there? Even orbits around Earth decay over time; every satellite up there will reenter eventually.

    Of course, this begs the question, "why's the moon still up there?" All right, so maybe there *are* stable orbits. But we don't have anything to put in orbit that we expect to use in 100 years, so we don't bother perfecting the process of putting stuff there.

  • More west coast (JPL specifically):

    Mars Global Surveyor [nasa.gov]

    Stardust [nasa.gov] comet sample-return mission

    Mars Pathfinder [nasa.gov] (the rover)

    They're also talking about a sample-return mission from Mars (in about ten years), missions to Europa, and setting up a sort of GPS/communications network around Mars to coordinate movements of and data return by various Mars rovers. They're not exactly lying down on the job.

    Disclaimer: I don't work for JPL...But I want to.

  • This reminds me of when I used to turn up the filament voltage on the tube tester to torture the poor little vacuum tubes.
  • Use your hard-earned Large Scale Integrated Circuits to fight the space program.

    Quick, before they invent something else for you to complain with.
  • Looks like they want to keep playing with the damn thing until they break it!!!
  • Does anyone know what OS their software is running on?

    I believe it's QNX or a flavor thereof.


    ...phil

  • What's next? They're going to bring it home?

    No, they're going to DISNEY LAND!

  • Well, since the camera can't focus on anything inside of 500 yards (it's designed for longer range viewing), maybe it would be nice to get this thing up and flying for a few days more, some more close-in pictures.
  • NASA is going to do all future space exploration with NEAR.

    NASA: Can we please have funding for another mission? We could build this great space craft and...

    Congress: What's wrong with NEAR? Can't you keep using that?

    NASA: We used NEAR last time. We put it on EROS and then we found there wasn't anything to do with it once it was there, so we took it back off. Can't we have one with more toys on it?

    Congress: No, go away. Can't you see we're busy?
  • Because they couldn't make up the data fast enough.
    ----
  • I thought TCP had some design limitations that cause it to fail when the signal delay exceeds some threshold. If so, that puts a limit on the distance TCP can function.
  • There was some talk very early on in the mission that they would try to touchdown and then leave the asteroid again. Recently they've only been talking about the touchdown (controlled crash landing?) because of the high risk of damaging the probe. Now that that's sucessful and they can apparently send a new program to the device, it's time to finish the show.

    I can't wait to see a picture of the mark they made on the surface of Eros. Way to go, APL! This is going out in style.
  • I don't think that's correct. Breaking free of Eros gravity would still leave it in orbit around the Sun. There's a minimum delta v necessary to get it on a trajectory where it would cross Earth's path when the Earth was there and an additional delta v necessary to get it in orbit around Earth.

    It's all academic at this point, the burn won't take place and if it had, it would not have placed the craft in orbit areound Eros, just landed it elsewhere. See this press release [jhuapl.edu] from JHUAPL.
  • There isn't enough propellant to get it back to Earth.
  • SPACE HACKER 1: Cool.. Um, let's land it again!!

    SPACE HACKER 2: yeah! I bet I can get it right in that big crater.

    SPACE HACKER 1: Let's see how low an orbit we can keep it in without it hitting!

    SPACE HACKER 2: Let's take it reeeally far out, then turn it around and ram the asteroid!

    Kevin Fox
  • Don't do it all at once.

    Instead, **Two** probes goes out, one lands, takes samples, and launches samples back into orbit where probe two rendezvous with the payload, and heads back Earthwards.

    Samples are then picked up, later, in Earth Orbit by the shuttle, or another probe, preferably a re-useable one, that would return it to the shuttle or the ISS. . . .

  • A stable orbit is impossible around a body like Eros -- its irregular shape perturbs the circular orbit so that the spacecraft would eventually crash into the surface. Lunar orbits decay over a manner of weeks for the same reason.

  • Just landing on the surface has limited scientific use, any lander which wants to really investigate primordial bodies such as asteroids and comets need to be somewhat more firmly attached. Look at the Rosetta site [esa.int] for an idea of some of the problems that landing on and doing science with a comet can cause.
    --
  • Can they get it inserted into a stable orbit around the rock again?

    Possibly, but why would they want too? They have exhausted the possibilities of that anyway, thats why the decided to land (ok, it was more complex than that, it has a lot to do with budgets as well as science).

    Can they escape the gravity of the rock entirely?

    Again, possibly, but why? All the instruments are designed to look at an asteroid from close up. There are probably too low on fuel anyway, and I doubt there is enough budget to do anything useable.

    Can they skitter across the landscape, trying for more landing sites and near-ground imaging?

    Which is probably what they are doing, taking more and more risks each time, because the are only going to have very very limited amounts of access left on the DSN [1]. Probably so long as the press is interested NASA will find them time on it though.

    Footnote [1] Initially typed as DNS...<sigh> I need to get out more :-)
    --
  • So, it takes a LOT of fuel to get there. If you take enough fuel to get BACK, you have to take even more fuel to get THERE, because you have to move the fuel to get back. Then you need even more fuel to haul the fuel to haul the fuel, and then some fuel to haul the fuel to haul the fuel to haul the fuel....

    OK - I'm totally freaked out now. I did a calculation in my head based on your reasoning and came up with an answer: NEAR would need an infinite amount of fuel to get there and back. I need to go to bed now...

  • I just don't understand this NASA / JHUAPL team. You'd think that crashing into an astroid would be enough, BUT NO, these guys need a second time. Just get it right the first time. You're giving us space-probe-obituary writers from getting ulcers.

    <serious>This is quite impressive.</serious>

  • And then send Bruce Willis up after it.
  • Because lunar landings have been patented by RAMBUS, and their lawyers are vigilanly protecting their intellectual property.

    I wouldn't imagine that anyone would consider an asteroid landing an obvious extention of a lunar landing.

    All your events [openschedule.org] are belong to us.

  • Unfortunately I can't seem to link to the exact comment of an archived story, but use your browser find for the word meat.

    One of the less-well known subtleties of slashdot is how to link to a comment in an archived story.

    http://slashdot.org/science/01/01/22/1710234.shtml #23 [slashdot.org]

    All your events [openschedule.org] are belong to us.

  • What's the Ring? This is a hard one.
  • There's no reason not to see what else this thing can do. It's completed it's mission, it's set to become nothing but space flotsam, why not fire it up and blow a few doughnuts?

  • From this last picture [nasa.gov] taken before landing, you can see that some sentient being intentionally commandeered the spacecraft's controls.

    This is probably to blind us from realizing that it's re-launching to invade packed with micro-organisms intent on feasting on human flesh

  • If it's been this easy, why haven't they just sent a rover out that can return asteroid samples? I mean, if they can set a craft down that wasn't even supposed to land, how much harder is it to make one that is?

    anacron
  • Am I the only one who thinks it is a little suspicious that NEAR, which was "not designed" to land on the asteroid, and had only a 1 in 100 chance of survival. The craft is now planning to take off and land again. I think the designers may have actually had some capability of landing in mind from the start, but didn't talk about it.
  • I heard someplace that most of the recent probes run VxWorks. I'm pretty sure Mars Pathfinder did. If it's not VxWorks then it's some other similar real time OS.
  • Because lunar landings have been patented by RAMBUS, and their lawyers are vigilanly protecting their intellectual property.

  • Of course they would never let us direct our tax dollars. First that would mean they would have to tell us where "THEY" are spending our money now, which ain't going to happen. Second, no one would want to pay for all those nasty little Police Actions we've been involved with in the last 20 years. Then where would all those Arms Dealers, OOPS, I mean Defense Contractors be.


    Jesus died for sombodies sins, but not mine.

  • But in order to get to your bed, first you have to get half way to your bed.

    And once you get half way, you'll have to go half of the distance remaining, and you'll still be only 3/4 of the way to your bed.

    But once you get 3/4 of the way to your bed, you'll have to go half of the remaining distance again, and then only be 7/8 of the way...

    I feel bad for you... you'll need an infinite amount of time to get to your bed.

  • They should set up an arcade-style coin-op outside and let people play with NEAR for $10,000 a shot. That way, they can generate enough cash for the next mission!

    "Whoa triple point-score! I just got NEAR to do a combo-move!"

    --

  • Man, I wish I worked there. I mean, hell, do they have anything else to do?

    I can see it now:

    Bob: "Well Bill, what do you want to do today."

    Bill: "I'm kinda bored, let's play with some multimillion dollar spacecraft."

    Bob: "Yeah, we haven't had news coverage since yesterday, so let's take NEAR up, fly it around the sun into the past and rescue some humpbakcs. Sound good to you?"

    Bill: "Yep"

    Bob: "What about next week?"

    Bill: "Well, I have plans to crash the Mir into a small glass filled with water."

    Bob: "Cool!"

    Geez...

  • Why would it take much extra fuel for it to go back to earth if they could make it take off? An object in motion will remain in motion in a straight line at constand velocity unless acted upon by an outside force.


    So if they can get a probe to land and take off, they can get the samples back to earth. All they really need is a little extra fuel to compensate for the small amount of gas in space.

  • I mean this is awesome news. It is almost unbelievable. NASA needs this PR. But how can people at home verify that this actually happened? Can telescopes see that far? I dont think so. All we have to believe them is their word, and people in desperate need of funding may do desperate things to get the PR they need to get it.


    I am NOT saying that I think this happened at all. I am just saying that we have no way of verifying that this is true.


    Well I dont want to start any conspiracy theories, I just thought others might find this possability interesting.

  • ::NASA engineer comes in the room::

    NASA Engineer: "Say guys, how many inches of height does the thing have to break to reach escape velocity?"

    APL Tech: "What the HELL did you just say??"

  • 200 years from now that asteroid will be a floating museum piece that people will pass by on their tour of the solar system. Leaving it there will be a reminder of what we went through to get that thing there.
  • Is a shame that they didn't pack enough fuel to just give it one good shove back towards earth orbit. Might be nice to grab it on a flyby with a shuttle, and see if NEAR managed to keep any dust along for the trip. Sure, it wasn't designed to take samples...but it wasn't designed to land and take off again either
  • Well, you'd need a lot more fuel to get the thing back to Earth orbit. Presumably a shuttle could go up and get it ... but I am guessing that the need to carry the return-trip fuel out there would make the thing a heck of a lot more expensive (because you'd also need more fuel to carry that additional fuel).

    But it would rock if they could do it.

  • Scientist 1 to Scientist 2: Stop hogging Lunar Lander [gamearchive.com]! You got past level 1, now I want to play!
  • Don't bring that thing back! It might round up all of the whales and keep them all to itself.

    Set yer phasers to stun. The Linux Pimp [thelinuxpimp.com]

  • excerpts:

    Scientists admit that the surface of Eros was not as interesting up close as it had been from wider views. "We definitely had 'space goggles' on," explained Farquhar.

    NEAR stayed on the asteroid for a few hours, made breakfast and idle chit-chat. But after a while, he could tell that it was his time to go. Firing its reverse-thrusters, NEAR left the surface never to return. NASA engineers excitedly noted that the landing and take-off have prepared the asteroid for future landings.

    This Won't Hurt A Bit. We're Just Going To Shove This Probe Up Your Asteroid [ridiculopathy.com]

  • Actually the fact that they could drop a probe onto Eros and maintain functionality brings an interesting idea to mind:

    While the best method we have of cataloging asteroids is currently by using optical telescopes (a tedious and slow method for tracking their movement as well), why not make a series of miniprobes that will land on every asteroid as they're detected, so that their movements could be tracked with radio telescopes instead?

    The benefits could be two-fold, one being that it would be easier to tell undetected asteroids apart from tagged ones, second being that any changes in path could be easily detected...

    For those saying "What'll it cost?", well, what would it cost to rebuild after a smaller asteroid decimates several hundred square miles? Or worst, what would it cost to rebuild after a large one hits? A few hundred million to billion in disposable probes designed as a radio collar for stray asteroids beats trillions in damage if one slips through undetected...
  • We'll find out in 2002 - there's a joint mission between NASA and the Japanese Institute of Space and Aeronautical Science called Muses-C that is due to try to collect and return samples from an Asteroid.
  • The whole idea of a government letting citizens direct their tax dollars is absolutely absurd. A government like that would collapse within 10-20 years. No government that has lasted long in history has let the citizens "Direct" their tax dollars. The United States was founded on the principle that the common citizens as a mass are absolute idiots, which I fully agree with them on. And supporting NASA is not a bad thing, all that "space age" crap in your SUV would not have occurred, if it weren't for NASA sponsored research.
  • Knowing NASA, they'll probably fire the thrusters and bring the whole asteriod home to Earth. Bean Bandit "Farewell Cruel World!"

  • APL roxors (Score:3)

    by Anonymous Coward on Tuesday February 13, 2001 @11:12AM (#434604)
    This is an outstanding achievement by the Johns Hopkins Applied Physics Laboratory, and they've certainly upped the competition with JPL et al.*

    But if you think this was great, just wait till you see what other missions JHUAPL has in store.

    • Putting a finger in the solar wind with ACE.
    • Testing suborbital plasma jets with APEX.
    • Probing a comet nucleus with CONTOUR.
    • Mapping Mercury with MESSENGER.
    • Dual spacecraft imaging solar eruptions in 3D with STEREO.

    ... and many more, some missions still active 27 years after launch.

    A number of these are excellent examples of the great, focussed science experiments that can be done under the faster-better-cheaper paradigm, and they're even competing for slots in the slightly more expensive Mid-Explorer program.

    *It should be noted in fairness that NEAR itself had a glitch; in December 1998 they failed to make their planned orbit insertion, and had to circle the sun 14 months before another approach could be made. (At that time I'm sure many /. posters were blaming NASA for yet another failure! Indeed the faster-better-cheaper policy was being severely criticized.)

    Dan

  • yah (Score:3)

    by Anonymous Coward on Tuesday February 13, 2001 @11:13AM (#434605)
    The latest plans are to attempt to fire the thrusters again on Feb 14..

    Hey those are my plans too tomorrow if you know what I mean...

  • Latest update (Score:3)

    by coreman ( 8656 ) on Wednesday February 14, 2001 @04:17AM (#434606) Homepage
    CNN is reporting that the project has been given another week of deep space network time to continue getting readings observations.

    http://www.cnn.com/2001/TECH/space/02/13/near.la nd ing.02/index.html

  • Re:Next (Score:3)

    by Teferi ( 16171 ) <teferi&wmute,net> on Tuesday February 13, 2001 @11:18AM (#434607) Homepage
    Yeah, there's some comment in the Linux TCP stack along the lines of
    /* delay timeout mandated by TCP spec, we'll have to use something else to talk to the University of Mars. */

    "If ignorance is bliss, may I never be happy.

  • Interplanetary Internet (Score:3)

    by powerlord ( 28156 ) on Tuesday February 13, 2001 @12:15PM (#434608) Journal
    As far as I know, people have been working on this for about two to three years already.

    A few quick articles from
    The New Scientist [newscientist.com]

    USA Today [usatoday.com]

    An interview with Vince Cerf [man.ac.uk]



    I'm not sure what has been done lately if anyone has some more recent links let us know.

  • I'll tell you what's next... (Score:3)

    by Wog ( 58146 ) on Tuesday February 13, 2001 @11:31AM (#434609)
    What's next?

    I'll tell you what's next. They'll make their final log entries, clean the crud out of their desks, and get ready for the next assignment. Why? Their funding runs out tomorrow at midnight. It's a shame.

  • Relative gravity (Score:3)

    by Speare ( 84249 ) on Tuesday February 13, 2001 @11:22AM (#434610) Homepage Journal

    Heard on CNN:

    The gravity is so weak that a 160 lb astronaut would "weigh" only about one ounce.

    Given this, I was amazed that a 5 mph crash wasn't just a complete bounce. They're running out of fuel on the NEAR, so I don't know what their next choice will be.

    Can they get it inserted into a stable orbit around the rock again?

    Can they escape the gravity of the rock entirely?

    Can they skitter across the landscape, trying for more landing sites and near-ground imaging?

    Interesting thoughts on what to do with a now-disposable craft.

  • They're going to bring it home? (Score:3)

    by mmmmbeer ( 107215 ) on Tuesday February 13, 2001 @11:45AM (#434611)
    No! They're going to let it land again. They just want to get a few more pictures with the resources remaining. The probe itself might be solar powered, but the thrusters aren't.

    By the way, does anybody else think the "official diagram" looks like legos?

  • so said..... (Score:3)

    by slashdoter ( 151641 ) on Tuesday February 13, 2001 @11:08AM (#434612) Homepage
    these guys at nasa and JH must have nothing better to do.

    "well thats it boys we have photed the entire rock what do we do now?"

    SPACE HACKER1: lets try and land it!

    SPACE HACKER2: COOL the next day

    SPACE HACKER1: well that was fun whats next?"


    ________

  • Leave it there!! (Score:3)

    by Johnny Starrock ( 227040 ) on Tuesday February 13, 2001 @11:28AM (#434613)
    We need to leave it there!!! How else will we know when Eros is about to hit Earth ??? It could kill your children!!!

    "TONIGHT ON FOX.."

  • This is a huge step for the space program... (Score:3)

    by digidave ( 259925 ) on Tuesday February 13, 2001 @11:14AM (#434614)
    Budget cuts have often come with the simple reasoning that not enough comes out of the space program and individual missions rarely bring in value to exceed their cost.

    The NEAR mission has been a total success beyond anyone's wildest dreams. They even recovered from almost certain tragedy when a mis-fire forced them a year off course. It has proven that sometimes the value of the mission does exceed the cost.

  • Re:Can I get me one of them? (Score:4)

    by Royster ( 16042 ) on Tuesday February 13, 2001 @11:28AM (#434615) Homepage
    Does anyone know what OS their software is running on?

    Vxworks, reportedly. It is a real-time OS.

    From the NEAR FAQ [jhuapl.edu]
    31. What kind of computer is on NEAR Shoemaker?
    The computer is a 16-bit machine called a 1750A. Based on a military standard that is about 10 years old, it runs at 12 MHz and has 256 KB of storage. This is equivalent to the PCs produced in the mid-1980s.

  • When they get finished... (Score:4)

    by homebru ( 57152 ) on Tuesday February 13, 2001 @11:07AM (#434616)
    When this team gets finished with little NEAR, they need to be put in charge of a Mars Landing project.

  • It's not Delta-s, but Delta-V (Score:4)

    by wowbagger ( 69688 ) on Tuesday February 13, 2001 @01:55PM (#434617) Homepage Journal
    Why would it take much extra fuel for it to go back to earth if they could make it take off? An object in motion will remain in motion in a straight line at constand velocity unless acted upon by an outside force.


    Were Eros not moving relative Earth, were Eros not at a different distance from the Sun than Earth, were spacetime flat between Eros and Earth, then yes, all it would take would be a small amount of fuel to get from one to the other.

    However:

    You have to put in a substantial change in velocity (delta-v) to get from Eros to Earth with any hope of not becoming a crispy critter in a meteoric reentry. You have to change your potential energy from the Sun's gravitational field. You have to make the transit so that you end up relatively motionless to the Earth at the time when you are relatively close to the Earth.

    So, it takes a LOT of fuel to get there. If you take enough fuel to get BACK, you have to take even more fuel to get THERE, because you have to move the fuel to get back. Then you need even more fuel to haul the fuel to haul the fuel, and then some fuel to haul the fuel to haul the fuel to haul the fuel....

  • The missed insertion was because of (tada!) a couple of bugs. Apparently, when they went to do the first orbital insertion burn, a transient impulse from engine startup caused a safety routine to trip (the safe level was set too low). Bugs in the shutdown code caused the craft to use the wrong thruster set (too strong) for attitude correction. The result was that the craft ended up over-correcting. By the time the spacecraft recovered from the mess, the Gyros had overloaded, the craft had gone into bigtime low-battery mode (and lost most of it's stored telemetry from the outage), and dumped 27-30KG of fuel trying to get back into a safe attitude. (overloaded gyros are blamed for much of the excessive fuel use)

    From the parts of the report that I read, they're not quite sure how it got into some of the states it did, nor -- given what they've reconstructed -- are they able to figure out how it recovered from some of the problems the bug induced.

    In any case, the loss of 28KG of fuel represented almost 1/3 of the fuel being carried at that point, and left them with almost zero reserve for the mission. This may be part of the reason why they decided on a soft-crash... They really don't have the reserve fuel to do much in orbit after the planed mission end-date.

    The lost fuel is probably also part of the reason why they don't have enough fuel to make it all the way back into orbit (much less back to earth).

    The complete report on the burn anomaly, as they call it, is available at http://near-mirror.boulder.swri.edu/anom/ [swri.edu]. ig'x 1MB. I've mirrored the report PDF on my home box [bcgreen.com]. (I found the mirror site a bit overloaded).
    --

  • No, they can't bring it home!!! (Score:4)

    by Demonikus ( 157686 ) on Tuesday February 13, 2001 @11:09AM (#434619)
    Everyone knows that asteroids are the main source of killer bacteria that will hunt the human race and turn us into mutants. I don't want to become a mutant. Unless I get superpowers like the X-men that is. Then it would be cool and I welcome all those killer bacteria. But only if I get superpowers!

  • What a waste! (Score:4)

    by Autonomous Crowhard ( 205058 ) on Tuesday February 13, 2001 @12:35PM (#434620)
    Look at this! This is nuts! I've never seen a bigger waste of money in my life!

    This type of tomfoolery is exactly why the government should be completely in control of space exploration.

    If NASA had handled this like they did on Mars, that ship would have STAYED crashed.

  • No Go for relaunch (Score:4)

    by GiantKeith ( 225194 ) on Tuesday February 13, 2001 @02:04PM (#434621)
    From the NEAR page and mirrors "Spacecraft not to be relaunched from Eros The NEAR mission operations team disabled a redundant engine firing today that would have been activated if it became necessary to adjust the spacecraft's orientation in order to receive telemetry from the ground. But because NEAR Shoemaker landed with a favorable orientation, and telemetry has already been received, it is no longer necessary to move the spacecraft from its resting-place on the surface of Eros." http://near-mirror.boulder.swri.edu/news/flash/01f eb13_2.html

  • Link to photos (Score:4)

    by codewolf ( 239827 ) on Tuesday February 13, 2001 @11:25AM (#434622) Homepage
    I don't know if this was posted before, but I assume that the pictures they take when this lifts off will look much the same as the ones that were taken on the landing as can be seen in this link: Landing Photos [nasa.gov]

  • Goof ups (Score:5)

    by Anonymous Coward on Tuesday February 13, 2001 @11:19AM (#434623)
    When NASA try to land something, it crashes. When they try to crash it, it lands safely and can even take off again.

    There's a pattern here. Can you see what it is yet?

  • Re:Pretty freaking cool. (Score:5)

    by sjames ( 1099 ) on Tuesday February 13, 2001 @12:01PM (#434624) Homepage Journal

    If it's been this easy, why haven't they just sent a rover out that can return asteroid samples? I mean, if they can set a craft down that wasn't even supposed to land, how much harder is it to make one that is?

    It looks easy because it worked. There's a lot of things in space exploration that seem like they should be easy, but don't work out that way. If it had crashed (a good probability) nobody would have thought it was easy.

    A big part in the decision to land was that the probe had already completed it's mission objectives with room to spare, and wasn't going to do much good just staying in orbit. They might as well take some chances and see how it works out. They had nothing to lose and plenty to gain by trying.

    OTOH, sending a probe with the explicit mission to land would be another matter entirely. Now the success or failure of the mission rides on doing something that's never been attempted before. The landing is no longer a free extra, it's an expensive design goal. It would have been a lot more expensive to purposly design the probe for a landing.

    There's also the P.R. angle. Every time A NASA mission misses an objective, they take crap from all sides, even if it was a minor secondary objective (especially if that objective had a lot of media appeal). OTOH, if a mission accomplishes all of it's objectives plus a few that nobody even thought of before launch, they get much needed good press.

    Of course, landing and takeoff from the asteroid is only half the battle. There's the issue of having enough fuel to return to earth orbit for pickup. Carrying that fuel would have added a lot to the mission cost, and made the landing more difficult (greater mass = more momentum = harder landing).

    Hopping NEAR around on EROS a few times will bring valuable real world experiance that will eventually improve the odds for a successful planned land, sample, and return mission.

  • NEAR Indestructable! (Score:5)

    by selectspec ( 74651 ) on Tuesday February 13, 2001 @12:21PM (#434625)
    Scientists in a final attempt to squeeze every dollar out the NEAR project are going to launch the tiny spacecraft into the Sun. The NEAR has already provided facinating data by landing on an astroid, by crashing into a moon crator, by dipping into the rings of Saturn, by plumitting into the deep oceans and being swallowed by a giant squid, and most recently by being used as a target during the latest anti-ballistic missle tests. Go little buddy! go!

  • Re:That's YOUR tax dollars, bub! (Score:5)

    by Denial of Service ( 199335 ) on Tuesday February 13, 2001 @11:36AM (#434626)
    I'd rather spend that money on a new SUV than on a ridiculously overpriced hunk of metal.

    Let's re-read this sentence a few times, shall we? I rest my case.

    ---

  • Somewhere inside Eros.... (Score:5)

    by mblase ( 200735 ) on Tuesday February 13, 2001 @11:21AM (#434627)
    *BANG!*

    "OW! Great Vrebzjneb, what the photon was THAT?"

    "It sounded like something crashing into the surface. Zarbonn, I thought you said you'd fixed the problem!"

    "I did, I did! Just let me go take a look...."

    time passes

    "...Aw, geez."

    "Well, what was it?"

    It's that stupid shiny box with wings. It crashed *again*, this time on the other side of the asteroid."

    "What!? You mean they sent a second one?"

    "No, no, it's the same one. It lifted off and crashed down again."

    "How did it do that? I thought you said you'd broken all the electronic bits off!"

    I said I'd broken the camera off so it couldn't see us. I didn't think it'd be able to lift off again after being beat up that bad in the first crash, so I left it alone. I figured the garbagemen would pick it up next Wurblesday anyhow, so I left it alone."

    "Well, that's just great. Now I'm going to have to help you pick it up and carry it all the way to the other side of the rock so that they *do* pick it up."

    "No, just relax, I'll give Zarkkel a call tomorrow afternoon and have him bring his tow rocket. He owes me a favor anyways."

    "Well, go up and break all the rest of the bits off so that it doesn't go off a third time. The last thing we need is to have that thing crashing through our ceiling like those poor Martians did just last cycle."

    "Already done. By the way, I thought I could swipe those solar cells and hook them up to the transmitter next weekend. If they provide enough extra power, we should be able to pick up the pay-per-view movie channel they're broadcasting from Titan."

    "Great! Say, you don't think that shiny transmitter box could have come from Earth, do you?"

    "I doubt it. After we buzzed their last box and made it crash into Mars instead of orbiting it, you'd think they'd have learned their lesson."

    "You'd think. 'Intelligent life' my berizzekl."

Slashdot Top Deals

Programmers do it bit by bit.

Close