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Parachute Problems Plague NASA's Flying Saucer

Posted by samzenpus on from the that-didn't-go-as-plan dept.

An anonymous reader writes: NASA's test of a Mars landing system came to a end Monday when the saucer-shaped vehicle's parachute tore away after partly unfurling high over the Pacific Ocean. NASA says they will provide more details at a news conference Tuesday. Another parachute failed during a similar test of a new Mars spacecraft last year. "This is exactly why we do tests like this," NASA engineer and LDSD mission commentator Dan Coatta said after the test. "When we're actually ready to send spacecraft to Mars, we know that they are going to work when that big mission is on the line."

8 of 41 comments (clear)

  1. I know a lot of this is cutting edge... by Viol8 · · Score: 2

    ... but the parachute? Really? If you know the speed and the density of the atmosphere you're going to deploy it in then the rest is basic physics and engineering. Just make sure you make the damn thing strong enough!

    1. Re:I know a lot of this is cutting edge... by pz · · Score: 5, Informative

      ... but the parachute? Really? If you know the speed and the density of the atmosphere you're going to deploy it in then the rest is basic physics and engineering. Just make sure you make the damn thing strong enough!

      You would think so, yes, except that no one has developed a parachute precisely (or even remotely) like this one before: it's the biggest super-sonic parachute ever (the ring portion of the 'chute deploys at over Mach 4 ... normal aerodynamics don't work there), AND, it has to be light enough to meet mission parameters for weight budget. While you might think it's basic physics, the empirical details are a bear to get right.

      It's not just that this is, in fact, rocket science, but really, really hard, cutting-edge rocket science.

      Having watched the NASA-released video, the failure mode appeared to be very different from the first test. The first test suffered from imperfect deployment that resulted in uneven loading and thus failure of the main 'chute. The droge (the first little 'chute) went out perfectly, but the main parasol failed to open. The second test failed more quickly, without even partial deployment of the main 'chute, as if it was immediately ripped apart. Watch the videos, they're fascinating!

      --

      Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
    2. Re:I know a lot of this is cutting edge... by pz · · Score: 2

      I don't know how you can see much from the second video, as NASA has not released anything high-res yet.
      could be the same problem as before, the feed is way too low-res to understand what went wrong.

      Thanks for the links. I had another look and you may be right -- it may be the same failure mode. In fact, it might be that the most recent 'chute actually lasted longer than the first one.

      --

      Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
    3. Re:I know a lot of this is cutting edge... by LeadSongDog · · Score: 2

      ... If you know the speed and the density of the atmosphere you're going to deploy it in ...

      Nontrivial. Requires the ability to forecast high altitude Martian weather years in advance. So far, we can barely manage a few days in advance for Earth weather. Then there's that minor detail of wanting some flexibility to adjust the atmospheric attack angle in case the arrival date isn't quite what was originally intended. No it isn't rocket science. It's way harder.

      --
      Oh, I'm sorry sir, I thought you were referring to me, Mr. Wensleydale.
    4. Re:I know a lot of this is cutting edge... by braindrainbahrain · · Score: 3, Interesting
      FAA Licensed Parachute Rigger here ("License to kill", lol).

      Parachutes don't just unfold, they actually deploy in a very controlled fashion. All it takes is something to initiate the sequence. In human parachutes, a pilot chute is released, which pulls out a deployment bag. The bag in turn does not open until suspension lines are stretched, and once the canopy is released from the bag, it inflates due to the difference in static air pressure within. vs dynamic air pressure outside (Bernoulli's principle). There are further mechanisms to slow down deployment in order to control the deceleration and opening shock (important for human well being). Problems occur if things happen out of sequence, or if the parachute is structurally unsound.

      I can't speak for the system NASA is using, but I expect there already is a unit to "unfold" the parachute, and it is all part of the parachute system already.

  2. Not for long... by xxxJonBoyxxx · · Score: 2

    >> Parachute problems plague flying saucer

    Not for long. The ground problem soon became a bigger issue.

  3. vueja de by meglon · · Score: 2

    This article is a reprint of an article in 1946 (Earth time frame) on the planet Remulak, followed by a large in-depth thread about New Mexico's climate (planet Earth, Sol system) during the summer months (Earth time frame).

    --
    Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
  4. Video by pantaril · · Score: 4, Informative

    https://www.youtube.com/watch?...
    You can see the parachute deployment and tear-down at 5:40