Curiosity's Parachute.

The stunning image taken from a satellite of Curiosity’s landing site shows the various parts jettisoned during landing.

One of the objects laying near Curiosity is the giant parachute. This is reportedly the biggest (half the size of a football pitch) and strongest chute in the known universe.

The question is did they ever consider the possibility of one of those massive Martian storms whipping up the parachute and entangling Curiosity and rendering her immobile?

There was a question at one of the press conferences about whether they could see the parachute blowing in the wind. The answer was that, since the Martian atmosphere was 1% as dense as on Earth, it was unlikely that enough force could be generated to lift the parachute.

We totally “junked” up the Earth. Now were working on the Moon and Mars!

To put WarmNPrickly’s post in context, they could not use the parachute all the way to the ground because the atmosphere is so thin. At Mach 2 Curiosity and the descent stage dropped away from the backshell and used the rocket propelled descent stage to finish the job of slowing down. The parachute was ceasing to be effective at that turns out to be well over 1000 miles an hour. Which puts into perspective the likely winds needed to move it, also noting that the parachute is still attached to the backshell and isn’t just lying about by itself. If it were unattached there possibly would be a risk it could blow around a bit in a proper storm. There might be some value is occasionally looking at it to see if has moved - as it would provide a bit of additional knowledge about the Martian winds. But unless it was cut free of the backshell it isn’t going far.

Another thing to consider. Even IF the thing could blow around, the chances of it actually coming right back towards the rover would be pretty slim. And the further away it landed the lower those chances. So, even if blowing, the chute causing a problem would be probably significantly lower than a dozen other things that could go wrong and mess up the mission.

And more importantly, in terms of keep the mission as cheap and payload capable as possible, the parachute was probably the only real choice. So, when you wanna do something and you pretty much have only one way to do it, you kinda gotta go with what you got.

Or has been moved.

<theremin plays>


NASA Image Gallery

From pic #39:
The Curiosity rover is approximately 4,900 feet (1,500 meters) away from the heat shield; about 2,020 feet (615 meters) away from the parachute and back shell; and approximately 2,100 feet (650 meters) away from the discoloration consistent with the impact of the sky crane.

I also heard them say that Mars has just enough atmosphere that you have to deal with it in order to avoid burning up on entry but not enough atmosphere to slow you down completely, hence the retrorockets (or air bags on the previous rovers). One of the reasons Mars has proven to be a tough nut to crack in terms of succesfully landing probes. That, and the darned metric system, of course. :smack: The good news is that we seem to be getting better at it.

Correction: use of Imperial units caused the crash.

I dunno. Lithobraking is the most sure fired way of hitting your target there is :slight_smile:

If you want to get really nit-picky, it was using both systems at the same time instead of choosing one or the other. (I would choose metric myself, FWIW.)

This Wiki article says that the parachute was designed to deploy at supersonic speeds (578 m/s) and then to slow the MSL to around 100 m/s before it was jettisoned and the powered descent began.

Surely we can agree that all distances should be measured in smoots - yes?

Only if we measure velocity in furlongs per fortnight.

Ack, I had the phase velocities out by one step of the landing. Indeed, the backshell is left at about 80m/s according to the NASA presskit. (PDF).

  1. Every time I see a new article about Curiosity, I get a frisson up my spine. Sorry, but this robot is right out of a golden-age SF novel up to and including the rock-blasting laser and the 3d imaging.

  2. Personally, I measure all velocity by siriometers per microfortnight. Call me a traditionalist, if you will.

You win the space thread.


I just came in to say that the father of a college classmate of mine designed that parachute and a predecessor used on an earlier Mars mission. She recently posted on Facebook to say how excited and proud the landing had made her.