back to article Oh chute. Doubts cast on ExoMars lander's 2020 red planet jaunt after another failed test

European Space Agency and Roscosmos's 2020 ExoMars launch is in jeopardy after a failed parachute test. The test was focused on the largest of the four parachutes, a predecessor of which had suffered a tear the last time around. Things went awry once more and an issue "similar to the previous test" was observed. Radial tears …

  1. Alister Silver badge
    Boffin

    The excessive rotation saturated sensors, leading to premature parachute ejection and, er, splat.

    Thanks for the highly detailed scientific analysis and descriptive summary... :)

    1. Marketing Hack Silver badge
      Childcatcher

      This sounded like the notes from sessions at some sex therapist's office.

      1. Francis Boyle Silver badge

        Of course

        that's aim of every article here. (With the possible exception of the ones about Kubernetes – I have no idea what going on there.)

  2. Ochib

    Isn’t the air density and gravity different to Earth’s. So how do they account for that when designing and testing parachutes

    1. Paul Kinsler

      Isn’t the air density and gravity different

      Presumably the test with a 29km drop height addresses the air density issue to some degree.

      1. Craig 2

        Re: Isn’t the air density and gravity different

        You plug all the numbers into a big supercomputer and hope that your mathematical model is close enough to reality....

      2. Pete 2

        I wonder if it'll be friends with me?

        > a 29km drop height addresses the air density issue

        You'd hope so.

        I'd be interested to know how they simulate the parachute opening while hurtling towards the ground at interplanetary speed?

        1. TeeCee Gold badge

          Re: I wonder if it'll be friends with me?

          I'd have thought that it'll aerobrake like fuck for a while before deploying any parachutes, so it won't be doing interplanetary speeds when that happens.

        2. phuzz Silver badge
          Flame

          Re: I wonder if it'll be friends with me?

          As TeeCee says, they'll have slowed down to merely ridiculous speeds by the time the parachutes deploy, but to test the heatshields at that speed, they strap them onto a rocket, and blast them at the earth's atmosphere, like this.

      3. MrReal Bronze badge

        Re: Isn’t the air density and gravity different

        Air density on Mars will be quite variable I'd expect, depending upon location.

        Perhaps they should use Apollo era parachutes, they all folded into an impossibly tight space yet never failed and they didn't have long to test them.

        Part of that 'missing tech'. I suppose, so careless.

        1. Mark 85 Silver badge

          Re: Isn’t the air density and gravity different

          Perhaps they should use Apollo era parachutes, they all folded into an impossibly tight space yet never failed and they didn't have long to test them.

          Maybe pride has something to do with it? It is an EU and Roscosmos project. They'd probably hate to have the US credit for the chutes. The other thing is Roscosmos does have quite a bit of experience using chutes.

        2. Anonymous Coward
          Anonymous Coward

          Re: Isn’t the air density and gravity different

          "Perhaps they should use Apollo era parachutes, they all folded into an impossibly tight space yet never failed and they didn't have long to test them."

          The Apollo parachute system was designed after about two decades of US experience - beginning in WWII - in dropping heavy loads retarded by multiple parachutes so that even if some parachutes failed, the load would survive. It was handy for air-dropping trucks and the like.

          One Apollo mission did suffer a parachute failure, as you can see here:

          https://en.wikipedia.org/wiki/File:Apollo_15_descends_to_splashdown.jpg

          The Apollo system was worked out so that a two-chute splashdown wouldn't harm the astronauts or split the command module open. It was a hard bump when Apollo 15 hit the water, but not a big problem.

          The thing about the ExoMars mission is that they're trying to get it to work without redundant parachutes - well, you would, wouldn't you?

          As for the differences between Earth and Mars atmospheres and gravity and so on: I'd guess that they've done some number-crunching to work out what combination of Earthly release altitude and subsequent parachute opening altitude corresponds to an aerodynamic loading on the parachute system similar to that which will be experienced when entering Mars's far thinner atmosphere at far higher speeds.

    2. Fungus Bob Silver badge
      Trollface

      "Isn’t the air density and gravity different to Earth’s. So how do they account for that when designing and testing parachutes"

      Mathematics

  3. Pascal Monett Silver badge

    Um, what about airbags ?

    They might want to start thinking about putting giant airbags around the payload, no ?

    1. Anonymous Coward
      Anonymous Coward

      Re: putting giant airbags around the payload...

      I'll make a call. What's the country code for phoning Bulgaria?

      1. jmch Silver badge
        Coat

        Re: putting giant airbags around the payload...

        The code you is +359

        and I suspect the number you want is 8008135

    2. Anonymous Coward
      Anonymous Coward

      Re: Um, what about airbags ?

      The lander is going to use retro rockets rather than airbags. I believe that decision was made because it's easier to guarantee that the rover will be able to extricate itself from the lander if you don't use airbags.

      On the one hand, on this side of the pond we don't have a good record of using airbags (Beagle) and on the other hand we don't have a good record of using retro rockets (Schiaparelli)...

  4. Anonymous Coward
    Anonymous Coward

    Really?

    8 comments thus far and no jokes about "premature...ejection"?

    OK, I'll go first.

    Perhaps they should coat the parachutes in Paroxetine.

    A poor effort, I know...

    1. wayne 8

      Re: Really?

      Covered in the first comment.

  5. Boris the Cockroach Silver badge

    All they

    are worried about is avoiding a RUD* event at mars

    Mind you.. whatever happened to that plan to send 16 people on a one way trip to mars in 2022?

    *Rapid Unexpected Disassembly

    1. OssianScotland Bronze badge
      Holmes

      Re: All they

      "Mind you.. whatever happened to that plan to send 16 people on a one way trip to mars in 2022?"

      I've got a little list.... they never will be missed...

      (not quite a G & S* icon, but same era)

      *G & T seems an acceptable alternative, but no suitable icon either

    2. Mike Shepherd
      Meh

      Re: All they

      ...whatever happened to that plan to send 16 people on a one way trip to mars in 2022?

      None of the people I suggested actually wanted to go.

      1. Richard 12 Silver badge
        Devil

        Re: All they

        And that was a problem?

      2. Evil Auditor Silver badge
        Devil

        Re: All they

        Ran into the same issue here. How did you dispose of your candidates?

  6. Stevie Silver badge

    Bah!

    While you are at it, double check that the old "negative altitude" bug has been corrected.

    Oh, and not by the guy who wrote the altitude checker.

  7. DougS Silver badge

    International cooperation

    Would come in handy here. NASA has already solved this problem, why don't they talk to NASA and use one of their proven solutions instead of inventing a new unproven one with a high risk overly complicated parachute deployment scheme?

    1. Francis Boyle Silver badge

      Re: International cooperation

      Covered by the AC above. The American approach to any problem is to throw more resources at it, hence redundant chutes. ESA doesn't have that luxury so American chutes probably won't work.

      1. DougS Silver badge

        Re: International cooperation

        Surely redundant chutes are less expensive than all this engineering and testing of a new solution, especially if it causes the entire mission timeline to be pushed back.

    2. beast666

      Re: International cooperation

      It's basically a EU vanity project. As with anything EU it is corrupt and doomed. Doomed I tells ya!

  8. wayne 8

    How many landers have been successfully sent to Mars? Not like this is virgin territory.

    1. TheProf
      Boffin

      Mars

      Sent? 100%

      Successfully landed? <60%

      1. Sgt_Oddball Silver badge
        Mushroom

        Re: Mars

        That's not true, there have been examples of Mars missions that didn't even make it off the launchpad (in one piece), nevermind getting as far as to crater on Mars. See here for more

        </pedant>

        Explosion because 'oops'

  9. eldakka Silver badge
    Coat

    Small errr, panel?

    ESA also intends to convene a panel of experts in Mars parachutes to ponder a way forward

    I'd expect that to be a pretty small panel, as I can't imagine the set of people who are experts in Mars parachutes as being very large.

    me: "Hey kid, what do you want to be when you grow up? Fireman?"

    kid: "I want to be a Mars parachute expert!"

  10. Brangdon

    Propulsive landing for the win

    It beats me why NASA love parachutes so much. ESA's problems here highlight how unreliable they are.

    1. cray74

      Re: Propulsive landing for the win

      It beats me why NASA love parachutes so much. ESA's problems here highlight how unreliable they are.

      NASA's track record highlights how reliable parachutes are. Parachutes worked successfully at Mars on Viking, Pathfinder, MER, Curiosity, Phoenix, and Insight.

      As I recall, NASA's never had a failed mission because of the parachutes themselves unless you count Genesis, which was a sensor failure (acceleration sensor installed during test). They've certainly had failures during testing - Orion and Dragon both have had recent parachute test problems, as did Curiosity - but beyond Genesis I can't think of a NASA mission scuppered by its parachutes.

  11. cray74

    Curiosity

    The Curiosity Rover also ran into parachute testing problems.

    "And the parachute blew apart basically. So the [wind] tunnel is fine, but the parachute, uh, it's a loss." --Doug Adams (the other one).

    The Curiosity team - which also assembled a team of Martian parachute experts - eventually decided that they were incapable of simulating Martian conditions in the wind tunnel. The air was just too dense and the parachute would work fine on Mars, but not terrestrial wind tunnels.

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