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


Forgot your password?
Space NASA

NASA's Fermi Spacecraft Dodged a Defunct Russian Satellite 47

g01d4 writes "On March 29, 2012, NASA scientists learned that the space agency's Fermi Gamma-ray Space Telescope was headed for a potential conjunction (close approach) with Cosmos 1805, a defunct Russian satellite from the Cold War era. The team knew that the only way to move Fermi would be to fire thrusters designed to move the spacecraft out of orbit at the end of its operating life. On April 3rd, shortly after noon EDT, the space agency fired all thrusters for one second. When it was over, everyone involved 'just sighed with relief that it all went well.' By 1 p.m., the spacecraft had returned to its mission."
This discussion has been archived. No new comments can be posted.

NASA's Fermi Spacecraft Dodged a Defunct Russian Satellite

Comments Filter:
  • In the story's release was a matter of national security, or just normal time lapse between an event's occurrence and discussion on /.
    • by Anonymous Coward

      It was due to time dilation.

    • by forand ( 530402 )
      No. It wasn't news then for the same reason there are no highly moderated posts on the article now: it isn't news. When this occurred the community (of gamma-ray astronomers) knew it was happening. It was never kept secret.
      • Yes, to prevent this satellite from possibly turning into junk now, we are now committed to turning it into space-junk later, for our kids satellites to deal with.

  • by Anonymous Coward

    Satellite Dodge You!

  • Nuke it from orbit, it's the only way to be sure. Not to mention that it's already in orbit.

    • Nuke it from orbit, it's the only way to be sure. Not to mention that it's already in orbit.

      Nice idea... simple solution... but if we take this seriously (sorry, too early in the morning for my sense of humour to have woken up yet) the only problem with it is that any explosive method of dealing with orbiting debris just creates lots of small and tiny pieces of shrapnel, and traveling through a field of that crap at orbital velocities is not going to be the highlight of your day. Not a problem if you are in an M1 Abrams battle tank, but satellites do not have armour, except for shielding against t

    • by wallsg ( 58203 )

      Nuke it from orbit, it's the only way to be sure. Not to mention that it's already in orbit.

      Be careful. It might not be Cosmos at all. It might be IKON and it'll nuke you back.

  • by jehan60188 ( 2535020 ) on Wednesday May 01, 2013 @05:46PM (#43604545)

    this is clearly a premeditated act of war by the russians. I propose we attack Uzbekistan.

  • Bad headline (Score:2, Informative)

    by MasseKid ( 1294554 )
    Dodged evidently doesn't mean it was going to hit it and they moved it out of the way. It was actually a "close approach" as stated in the summary (gotta love sensationalism, right?). Except, close approach actually means within 700' of the defunct satellite, which really isn't all the close at all.
    • Re:Bad headline (Score:5, Informative)

      by Doug Otto ( 2821601 ) on Wednesday May 01, 2013 @06:00PM (#43604675)
      From TFA:

      Though Fermi was expected to miss Cosmos by several-hundred feet, NASA scientists knew from experience that forecasting spacecraft positions a week in advance isn’t an exact science. For example, Iridium 33 and Cosmos 2251 collided in 2009 even though they were predicted to miss each other by approximately 1,900 feet. This was the first known satellite-to-satellite collision.
    • Re:Bad headline (Score:5, Informative)

      by X0563511 ( 793323 ) on Wednesday May 01, 2013 @06:02PM (#43604695) Homepage Journal

      If there was any debris from the Cosmos (either directly from it, or from interactions with other junk or such) could be within that area.

      Our radar is not good enough to make it safe enough to pass by that closely.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      700' is ridiculously close when you're going miles per second and the Earth's atmosphere is constantly changing, changing each object's orbits by similar amounts regularly due to drag.

      Heck, if the RADAR producing the data has a couple of microseconds of jitter in it's clock, the propagation estimates could be off by that amount....Basically, 700' is pretty close to the noise of our estimations for orbital objects like this, and it's just better to be safe than sorry. Not to mention, who knows what small pi

    • Except, close approach actually means within 700' of the defunct satellite, which really isn't all the close at all.

      Except, you don't know the margin of error in either our knowledge of Fermi's orbit or that of Cosmos 1805's orbit. But I'd be willing to bet that the margins are large enough that a predicted 700' approach would place the two spheres of position sufficiently in overlap that there was a non-zero chance of collision.

    • by AK Marc ( 707885 )
      The margin of error is greater than 700', so it's improbable but possible. And with such dire consequences in the event of a collision, it was safer to move it.
    • Actually, revised calculations made their pass even closer, within 30 milliseconds [csmonitor.com]. I may be doing the math wrong, but it seems like that's much closer, like an order of magnitude closer than 700' and then some.

  • It seems to have reached a point where the amount of orbital garbage is causing major (and expensive) problems.
    I think that if anyone puts a sat in orbit without dodging capability, they are fools, and potentially contributing to the 'littering' of orbitals.

    It's past time to start working on and TESTING solutions to clean up the orbitals before it gets even more out of hand.

    Or is this some Earthshade Anti-Warming scheme I missed hearing about?

    • by bobbied ( 2522392 ) on Wednesday May 01, 2013 @07:18PM (#43605209)

      Oh man, where do you start with this?

      In LEO, orbiting debris are a self limiting problem. They will eventually deorbit on their own. So I guess that's not an issue for you.

      In Geosynchronous orbit, every object is going to be pretty much moving in exactly the same direction anyway so the relative velocity is really small. The risk of collision is pretty small and the debris created would be minimal at low collision energies.

      Outside these two areas, collecting orbiting debris, which vary in size from a few tons down to a few grams is a daunting task at best. How do one would imagine this could be done is the stuff of science fiction at best. Any collection system would by definition need to collect varying sized objects passing though a huge (by human standards) volume. This means there will need to be some pretty large structures launched, flown in space, survive the impact of collecting the desired objects and dispose of the collected mass. All this will need to happen without adding to the problem....

      I just don't see how we are going to do this.

      Personally, mankind would be better off if we took a debris mitigation strategy that required all launched hardware be mindful of not creating debris in orbits that would not naturally reenter within 5 years or so. We do this kind of thing now, at least the responsible people throwing most of the stuff in to space do, no telling what DPRK does.

      Other than that, we might want to start thinking about building "space tugs" that can capture the junk that's collecting in geosynchronous orbit, tug it to less popular locations and work on ways to recycle parts of it. It sure doesn't seem worth the effort to deorbit the stuff that is that high up.

      • by barjam ( 37372 )

        Wouldn't altitude and velocities in geosynchronous orbit have to be exactly identical by definition? Otherwise it wouldn't be geosynchronous orbit and stuff would drift forward or backward.

        • Re: (Score:3, Informative)

          by Anonymous Coward

          If you want to be pedantic, no. "Geosynchronous" means that it has a 1-day orbital period but does not specify the inclination or eccentricity of that orbit. The correct term for what you're talking about is "geostationary".

          • The GP has a point. The GGP states they have little relative velocity, which means they would have to have the same inclination. A geosynchronous satellite that is moving in the opposite direction is going to have a ton of relative velocity and would have disastrous results in the event of a collision.

            So perhaps the GPP meant geostationary (or close to it), not just geosyncronous (if the only definition of that is the satellite has a 1-day orbit). However, I am not an astrologer or any sort of scientist, so

      • A very, very large aerogel sponge. Getting the actual sponge to deorbit would be a bitch, but at least it'd be easy to track.

    • by k6mfw ( 1182893 )
      perhaps international policies to prevent a "tragedy of the commons."
  • So the conjunction was averted and didn't happen?

  • They got to watch out for Yuri Gagarin too. According to legend, he is still flying up there.
  • Orbit. So easy to make an object leave it's orbit. Change is vertical moment. So, a ground based laser, solar powered, naturally, is used to target junk just under the base station. A few minutes a days and this junk will be coming down. Why are we waiting?
    • by cusco ( 717999 )
      Because no one is willing to pay a gazillion dollars to provide bonuses to aerospace executives. Once the C-suite execs find a sponsor you'll suddenly hear what a high priority clearing out orbital debris has become.

Today is the first day of the rest of your lossage.