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NEAR to Fly Once More

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?"

13 of 168 comments (clear)

  1. Re:Can I get me one of them? by Royster · · Score: 4

    Does anyone know what OS their software is running on?

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

    From the NEAR FAQ
    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.

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  2. When they get finished... by homebru · · Score: 4

    When this team gets finished with little NEAR, they need to be put in charge of a Mars Landing project.

    1. Re:When they get finished... by Stephen+Samuel · · Score: 4
      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/. ig'x 1MB. I've mirrored the report PDF on my home box. (I found the mirror site a bit overloaded).
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      Free Software: Like love, it grows best when given away.
  3. It's not Delta-s, but Delta-V by wowbagger · · Score: 4
    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....

  4. No, they can't bring it home!!! by Demonikus · · Score: 4

    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!

  5. What a waste! by Autonomous+Crowhard · · Score: 4
    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.

  6. No Go for relaunch by GiantKeith · · Score: 4

    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

  7. Link to photos by codewolf · · Score: 4

    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

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    http://www.codewolf.com - Just good stuff to waste time
  8. Goof ups by Anonymous Coward · · Score: 5

    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?

  9. Re:Pretty freaking cool. by sjames · · Score: 5

    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.

  10. NEAR Indestructable! by selectspec · · Score: 5

    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!

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    Someone you trust is one of us.

  11. Re:That's YOUR tax dollars, bub! by Denial+of+Service · · Score: 5
    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.

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    Slashdot: News For Zealots. Stuff That's Hypocritical.
  12. Somewhere inside Eros.... by mblase · · Score: 5
    *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."