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 …
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.
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.
"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.
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)...
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'
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!"
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.
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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