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posted by martyb on Tuesday December 05, @04:09AM   Printer-friendly
from the ping-time:-7.04E7-ms dept.

NASA has used Voyager 1's trajectory correction maneuver (TCM) thrusters in place of its attitude control thrusters. The move could extend the amount of time NASA can communicate with Voyager 1 by two to three years:

NASA scientists needed to reorient the 40-year-old Voyager 1 -- the space agency's farthest spacecraft -- so its antenna would point toward Earth, 13 billion miles away. But the "attitude control thrusters," the first option to make the spacecraft turn in space, have been wearing out.

So NASA searched for a Plan B, eventually deciding to try using four "trajectory correction maneuver" (TCM) thrusters, located on the back side of Voyager 1. But those thrusters had not been used in 37 years. NASA wasn't sure they'd work.

Tuesday, engineers fired up the thrusters and waited eagerly to find out whether the plan was successful. They got their answer 19 hours and 35 minutes later, the time it took for the results to reach Earth: The set of four thrusters worked perfectly. The spacecraft turned and the mood at NASA shifted to jubilation.

Also at Space.com.


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  • (Score: 1, Funny) by Anonymous Coward on Tuesday December 05, @05:18AM (6 children)

    by Anonymous Coward on Tuesday December 05, @05:18AM (#605514)

    Hmmm. Haven't used a slide rule in at least 37 years. I wonder if I could make one work if I fired it off today?

    • (Score: 0) by Anonymous Coward on Tuesday December 05, @07:12AM

      by Anonymous Coward on Tuesday December 05, @07:12AM (#605528)

      I downloaded a slide-rule app.

    • (Score: 2) by FatPhil on Tuesday December 05, @10:07AM (4 children)

      by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Tuesday December 05, @10:07AM (#605567) Homepage
      Assuming you nkew how to use it in the first place, I reckon it should still work. However, I reckon your 1980 pocket calculator might well be suffering from solder whiskers. And if it used that rubber connector, if that's degraded there's a good chance the screen's no longer connected properly to the mobo.
      --
      The "free" in #freearistarchus is the "free" in "free jazz"
      • (Score: 2) by RS3 on Tuesday December 05, @04:24PM (3 children)

        by RS3 (6367) on Tuesday December 05, @04:24PM (#605689)

        I not only still have and often use my 1978-ish Casio calculator, but many other significantly older PC board based electronics. As a hands-on electronics hobbyist / tech (and EE) I've never seen solder whiskers, but I don't doubt their existence. From a bit of research, I gather that solder whiskers form from a fairly rare combination of factors, so are likely overall fairly rare. I've seen corrosion cause resistive shorts, usually due to condensing humidity or some kind of liquid intrusion.

        Yes, I've had to clean the rubber LCD connectors in the Casio and many other devices with LCD displays. It's generally not too difficult to do.

        • (Score: 2) by Unixnut on Tuesday December 05, @05:24PM (2 children)

          by Unixnut (5779) on Tuesday December 05, @05:24PM (#605715)

          > As a hands-on electronics hobbyist / tech (and EE) I've never seen solder whiskers, but I don't doubt their existence.

          My understanding is that solder whiskers (I know them as "Tin whiskers") are a relatively new phenomenon, caused by the removal of lead from solder (for environmental reasons).

          So anything that is "RoHS Compliant" will basically fail due to such whiskers, while older tech that still used lead in the components and solder will last a lot longer, and will generally fail for other reasons (most usually Capacitors).

          It is pretty much impossible to find anything other than lead free solder/components nowadays (outside of aerospace/defense), so I guess we just have to resign ourselves to electronic goods having a "shelf life" (and of course, more landfill due to electronics lasting shorter).

          • (Score: 1, Interesting) by Anonymous Coward on Tuesday December 05, @08:16PM (1 child)

            by Anonymous Coward on Tuesday December 05, @08:16PM (#605796)

            My understanding is that solder whiskers (I know them as "Tin whiskers") are a relatively new phenomenon, caused by the removal of lead from solder (for environmental reasons).

            Well, sortof. Tin whiskers is a very old problem discovered in early telephone systems, and the addition of lead to solder has been known to reduce (but not eliminate) the problem for a similarly long time. My impression is the physics behind this process and even the reasons why lead actually makes a difference are not very well understood.

            Lead-free solders use different methods to mitigate the problem, which seem to mostly work just fine, but we have only ~12 years of experience with RoHS. Time will tell.

            • (Score: 1) by toddestan on Friday December 08, @03:04AM

              by toddestan (4982) on Friday December 08, @03:04AM (#607072)

              Anecdotally, I've found a lot of the DDR2-era hardware to not be particularly long lasting. That would be about the time ROHS rolled out. By the time DDR3 came out, they must have figured it out, as I haven't seen the same problems - though that stuff is newer, of course.

              The previous generation DDR hardware seems to be more reliable, though with that stuff you have to worry about bad capacitors. Though at least that's something I've had luck repairing.

  • (Score: -1, Troll) by Anonymous Coward on Tuesday December 05, @06:59AM

    by Anonymous Coward on Tuesday December 05, @06:59AM (#605523)

    Cool story, nasa.

  • (Score: 1, Funny) by Anonymous Coward on Tuesday December 05, @07:20AM (3 children)

    by Anonymous Coward on Tuesday December 05, @07:20AM (#605531)

    That violates the EULA.

    • (Score: 5, Funny) by maxwell demon on Tuesday December 05, @08:34AM (1 child)

      by maxwell demon (1608) Subscriber Badge on Tuesday December 05, @08:34AM (#605549) Journal

      Right. Let's send an army of lawyers to Voyager 1!

      --
      The Tao of math: The numbers you can count are not the real numbers.
      • (Score: 4, Touché) by Shimitar on Tuesday December 05, @09:34AM

        by Shimitar (4208) Subscriber Badge on Tuesday December 05, @09:34AM (#605562) Homepage

        Please, not an army... SEND THEM ALL!!

        --
        Coding is an art. No, java is not coding. Yes, i am biased, i know, sorry if this bothers you.
    • (Score: 2) by ledow on Tuesday December 05, @09:54AM

      by ledow (5567) on Tuesday December 05, @09:54AM (#605564) Homepage

      Luckily, I don't think they pay by annually-recurring licence.

  • (Score: 3, Informative) by inertnet on Tuesday December 05, @09:18AM (3 children)

    by inertnet (4071) on Tuesday December 05, @09:18AM (#605557)

    They got their answer 19 hours and 35 minutes later

    That's the one way time. They had to wait twice as long after sending their commands.

    • (Score: 5, Interesting) by isostatic on Tuesday December 05, @01:35PM (2 children)

      by isostatic (365) on Tuesday December 05, @01:35PM (#605614) Journal

      They knew the thrusters wouldn't ignite until Tuesday 04:14. At 04:13 they knew the thrusters were off and hadn't been turned on. Then from 04:14 they had no idea if the thrusters had turned on or not, and didn't until 23:49.

      The question I suppose is what does 'now' mean. Did they fire up the thrusters at Tuesday 04:14, when the command reached the ship, or did they fire them up the Monday at 09:39 when they issued the command on their keyboard.

      (Times changed to protect the innocent)

      • (Score: 2) by crafoo on Tuesday December 05, @06:06PM

        by crafoo (6639) on Tuesday December 05, @06:06PM (#605730)

        In terms of relativity, now means whatever it means from your reference frame. There is no "prime" reference frame. Now means different things depending on your reference frame.

        In terms of voyager and the distances involved: just think of it as really bad display lag. like, really pretty bad. about as bad as a Sony, not quite as bad as Samsung.

        In terms of Voyager 1, it fired it's thrusters when the signal was received telling it to do so. We found out about it some time later, at approximately distance/c later in voyager's frame (voyager isn't traveling at a significant fraction of c).

      • (Score: 2) by inertnet on Tuesday December 05, @10:22PM

        by inertnet (4071) on Tuesday December 05, @10:22PM (#605854)

        The context is that the engineers fired up the thrusters and started waiting. The clock started ticking when the command was sent and stopped when the answer was received. To me that's a round trip.

  • (Score: 0) by Anonymous Coward on Tuesday December 05, @03:06PM

    by Anonymous Coward on Tuesday December 05, @03:06PM (#605651)

    Here is a link with more information

    https://space.stackexchange.com/questions/23895/how-do-voyager-1s-trajectory-control-thrusters-differ-from-its-attitude-control/23896#23896 [stackexchange.com]

    It seems that these are all hydrazine thrusters.

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