Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
Space Science

ESA Satellite Recovers: Total Loss To Geostationary 47

Posted by timothy from the falling-forward-all-the-time dept.
Slimbob writes "About 2 years ago an Ariane 5 rocket malfunctioned and left a very expensive Artemis satellite in an unusable orbit. Well, over the course of 18 months, the European Space Agency actually managed to push the satellite into a usable orbit using measly 15mN ion thrusters! They managed the feat by reprogramming about 20% of the original control software and uplinking the patches to the satellite! See the ESA press release . Achievements include the first first major reprogramming of a telecommunications satellite, the first orbital transfer to geostationary orbit using ion propulsion, and the longest ever operational drift orbit."
This discussion has been archived. No new comments can be posted.

ESA Satellite Recovers: Total Loss To Geostationary More

ESA Satellite Recovers: Total Loss To Geostationary

Comments Filter:

  • Fuel (Score:3, Interesting)

    by GigsVT ( 208848 ) on Wednesday February 19, 2003 @02:11PM (#5336443) Journal
    The article says they used up almost all the ion fuel, but yet it will still have enough for 10 years of trim thrusting, was the original planned life much longer, or did it just have that much extra fuel?

    • Re:Fuel (Score:5, Informative)

      by Simon Field ( 563434 ) on Wednesday February 19, 2003 @02:57PM (#5337001) Homepage


      The article makes a distinction between the Xenon ion thrusters and "chemical propellant". The last orbital adjustments were made with "small chemical propellant thrusters, activated for the first time since launch".

      It looks like the 10 years number does not refer to the Xenon ion thrusters.

      • Re:Fuel (Score:2, Interesting)

        by phobonetik ( 522196 )
        I've been reading a few recent slashdot articles on Ion thrusters (e.g. the space ladder, I think). Where's a good intro on the things? I'm almost pleased they exist, sounds nice and sci-fi, even if i'm 21 :)

    • Re:Fuel (Score:4, Interesting)

      by warpSpeed ( 67927 ) <slashdot@fredcom.com> on Wednesday February 19, 2003 @05:44PM (#5338665) Homepage Journal
      The article says they used up almost all the ion fuel, but yet it will still have enough for 10 years of trim thrusting, was the original planned life much longer, or did it just have that much extra fuel?

      Since the operational drift is so much longer then what was originaly antisipated, I would be that they are consuming much less propellent then originaly expected, so they are able to get "10 years" out of what is left.

      GStar 3 or 4, put up by GTE in the late 80s, had a simmilar fate. It was lobbed into a bad orbit, written off (paid for), and then slowly (very slowly) moved into a "usable" orbit. The satellite had less propellent avaiable to it, so it was allowed to drift up and down, and side to side.

      GTE sold cheap time on the satellite since you could only get 5 to 20 minutes at a time without re-aiming your uplink antenna. A friend of mine wrote the software (in basic) that people used to aim thier uplinks antennas. However, since the satellite was paid for already, any money coming in was gravy at that point.

  • of these guys and their accomplishment. Some fsking stand-up engineering for sure.

  • This isn't the first innovative satellite recovery (Score:5, Informative)

    by Sierran ( 155611 ) on Wednesday February 19, 2003 @02:16PM (#5336495)
    A few years ago, Hughes Communications engineers used a lunar orbital slingshot maneuver to recover AsiaSat 1, which had been stranded in an unusable orbit. The insurance consortium that had already paid out for the satellite accepted a salvage deal with Hughes, who had manufactured it in the first place (it was launched on a Proton out of Baikonur). While they were using the designed maneuvering engines, as opposed to the stationkeeping thrusters, they ended up sending the satellite completely out of cislunar space [everything2.com] in order to make the save.


    Reference: Flug-Revue [rotor.com]

  • "15mN ion thrusters" (Score:4, Funny)

    by rthille ( 8526 ) <web-slashdot@@@rangat...org> on Wednesday February 19, 2003 @02:26PM (#5336625) Homepage Journal
    15mN ion thrusters
    See honey, size doesn't matter!
  • Link quality was almost perfect: a bit error rate better than 1 in 109 was measured. This means that 1 bit at most is received erroneously per 1 000 000 000 bits transmitted.

    I don't get this bit. If the bit error rate was measured at 1 in 109, surely that means that there should be approximately one bit received erroneously per 109 bits? How do they get a billion? Or is that in conjunction with an error correcting code?

  • Cool Hack (Score:3, Insightful)

    by JGski ( 537049 ) on Wednesday February 19, 2003 @03:05PM (#5337089) Journal
    This kind of hacking has been going on for >30 years by NASA and the military to save satellites. Certainly saving expensive spacecraft is one of the clearly positive aspects of hacking and hacking talents.

  • Great (Score:2)

    by tsa ( 15680 )
    What a fantastic achievement. Let's give three hurrays to Sir Isaac Newton, who made this all possible.

  • Expect more ions in the future (Score:5, Interesting)

    by TheSHAD0W ( 258774 ) on Wednesday February 19, 2003 @03:46PM (#5337473) Homepage
    The results of this botched lofting actually bode well for future satellite installations. Admittedly, using ion thrusters for final delivery would take much longer than using standard rocket technology, but it would also be enormously less expensive. The weight savings would be large, at a stage where weight is the most expensive part of the flight.

  • Wow (Score:4, Funny)

    by robbo ( 4388 ) <slashdot@NosPaM.simra.net> on Wednesday February 19, 2003 @04:03PM (#5337645)
    Imagine trying to do that to a windows box. With each patch you'd have to engineer a probe to go up and hit 'Ok' when it reminds you to reboot. ;-)
    • Nah, you just get one of those l33t TCP-KVM things. Plug in PS/2 keyboard and mouse, and VGA, then VNC into it :) It's the best way to turn commodity PC hardware into something resembling a serious server.
  • About 2 years ago an Ariane 5 rocket malfunctioned and left a very expensive Artemis satellite in an unusable orbit. Well, over the course of 18 months, the European Space Agency actually managed to push the satellite into a usable orbit using measly 15mN ion thrusters!

    Damn. It's obvious that Planetary's [earthlink.net] efforts on behalf of mankind have been negated yet again...

    "Why do I even have to say this? Why do I have to say

    'Get off the unique and probably alien plinth that zaps the
    unwary?' What is wrong with my life that I have to say
    these things out loud to someone?"

    - Jakita Wagner, Planetary #4 [earthlink.net]

  • On patching satellites (Score:3, Interesting)

    by bill_mcgonigle ( 4333 ) on Wednesday February 19, 2003 @05:53PM (#5338766) Homepage Journal
    Does anybody know what kind of authentication they use and how they deal with failed patches?

    Seems like somebody probably thought it through for the cost of one of these programs.
    • Just a wild guess, but it's probably similar to how the Tivo does its update procedure. There are 2 boot partitions on the system...when an upgrade comes through, the system tests the integrity of the upgrade, switches the boot partition and reboots...

      I would figure they probably use a more elaborate system...but it's probably the same in practice...of course, they have simulators/emulators on the ground that can accurately recreate the satelite's internal components...so, there should be no bugs in the system when the patches are sent...

      The only thing they'ld need to worry about is noise on the uplink (corrupted files) and possible hardware failure...corrupted files could be tested for prior to patching, and hardware problems can be fixed by having backup systems...
    • With adding some redundancy it is possible to have a reliable communication channel. Please realize that this kind of techniques have been used for several scientifical satilites going to the other side of our solar system.

  • include a docking port, so you can send a 'cargo satellite' after it to refuel your $10^8 satellite?

    This would be expensive [1], but a lot less so than writing off a satellite that ends up in the wrong orbit. Also, you could keep your satellite operational far longer than usual: communications satellites IIRC are written off when they run out of fuel, rather than because of mechanical/electrical failures.

    1: or would it? You'd have to launch it, but you're launching just a load of fuel with some maneuvering motors attached to it.

    • _much_ cheaper to use solar-cell powered ion thrusters... which is what they did. That way, your fuel is already up there.

      -T

    • They don't include a docking port to take on more fuel, for the same reason that the Shuttle has never performed its design goal of returning a sat to earth for servicing.

      The satellites electronics go obsolete before they run out of fuel. In general it is better for a company / country to boost a whole new sat with higher bandwidth, better resolution, more accuracy (depending on the sats design goal) and move the old one into a graveyard orbit.

      The exceptions to this tend to be science sats which are hard to get funding for and / or in weird orbits. In those cases it is a choice between doing ground side changes to prolong the sats functional life or having no sat at all.

      This instance was a unusual one becuase it was a brand new com sat that failed to achieve proper orbit; not an end of life sat running out of station keeping fuel. It isn't cost effective to add expensive refueling capability (and pay for the launch of refueling 'cargo satellites') to save the rare satellite that ends up in a wrong orbit that doesn't send it back into atmosphere and whose payload is fully functional. On a cost basis it is better to just get the insurance payout and build another sat.

  • Awe (Score:1)

    by virve ( 63803 )
    Wow, one should have deep, deep respect for these people. The room for error is probably very small. When trying to patch substantial parts of the satellite's software the perils are obvious: any issues communication and stabilization might cause the loss of the spacecraft. And it is a bit difficult to reach the reset button...

    Are there any means of going back to a safe version of the firmware, or are there means of automatically rebooting the on-board computer?

    virve
    --
    • Are there any means of going back to a safe version of the firmware, or are there means of automatically rebooting the on-board computer?
      You can bet that there is at least one level of safemode in that thing. DS1 [nasa.gov] had such, and both hardware and communications-loss watchdog timers. DS1 recovered from a total failure of its star tracker [nasa.gov] to boot, and was navigated for some time using only its science camera and on-board software hastily written and uploaded for the purpose.

Slashdot Top Deals

"The four building blocks of the universe are fire, water, gravel and vinyl." -- Dave Barry

Close