A Curious question about the Mars Rover.

First things first, this isn't a conspiracy question, just something that has been puzzling me. The only time I've ever used a parachute was in gym class, which by the way was ridiculous, so I'm just trying to understand how they work outside the atmosphere of elementary school.
I was watching a Discovery channel show about the making of the Curiosity Mars rover and there were a few things that just didn't seem to make sense. No, I'm not talking about the JPL guy who has two earrings and looks like Michael Madsen from the Kill Bill movie, even though I find it odd when he stood directly in front of the powerpoint projector with the light in his eyes.
I'm also not talking about how they had to re-design the motors because nobody thought to do an extended run test which is standard procedure for virtually every moving part ever made.
I'm talking about the parachute.
It has always been my understanding that Earth was the only planet with air on the surface, it has also been my understanding that air is what is needed to fill the parachute and make it expand. The only time I have ever seen a parachute on a space craft was during the return or re-entry phase, never during the Moon landing or when docking in space. When they showed the last Mars Rover mission it was surrounded by inflatable balls like the Val Kilmer movie and bounced across the surface. So what gives? Why have they never used a parachute before, and what has changed to allow for it's use today?

Interesting question.

What is really odd is how they usually crash land these ultra sensitive pieces of equipment. What a barbaric, risky way of landing.

Mars curiosity allegedly and propulsion to have it hover and land.


On the conspiracy note I have heard that some of the rovers are actually somewhere in the deserts of our world. All images and video are already save recorded and pre scheduled for trickled outputs to fool the masses. Great way to generate, reallocate funds while making it appear it was spent. Pictures to prove.

Mars has a thin atmosphere. The last rovers were light enough that they could hadle impact after atmosphere drag/use the impact and bounce technique you mentioned. The latest rover is around the size of a VW bug and weighs more, so a different method was needed.

The thin atmosphere provided enough drag for the parachute... everything worked great.

Originally posted by AkumaStreak
Mars has a thin atmosphere. The last rovers were light enough that they could hadle impact after atmosphere drag/use the impact and bounce technique you mentioned. The latest rover is around the size of a VW bug and weighs more, so a different method was needed.

The thin atmosphere provided enough drag for the parachute... everything worked great.

edit on 8/11/2012 by AkumaStreak because: (no reason given)

Stole my thunder.

Also, the "inflatable ball" method was tested because it's believed to be the best method for landing particularly heavy and/or large equipment. If successful, future programs where unmanned construction is required on the surface could then be possible.

EDIT: the parachute used this time was cost friendly.

The parachute was tested in a huge wind tunnel on Earth. It was a super-sonic parachute that reduced the speed of the vehicle while ripping through the thin atmosphere of Mars. The vehicle was actually landed by a sky crane, a multiple rocket device that slowed it down and actually dropped it off with ropes to the surface and then crashed itself away from the rover. This is a simplistic explanation.

Entry, Descent, and Landing Configuration

I have to say that i dont believe the martian atmosphere is so thin....nasa claimed before that pics of ice werevavtually dry ice. But can dry ice really exist in the atmosphereic pressure they claim it has? And they at one point said it gets up to 80 degrees on mars, at another point they said it gets up to zero. Contradiction much? Wtf? Of course if earth only got to 80at the equator itd be a mighty cold place to be....

And all these arguments against ufos start with "superluminal travel is impossoble" lmao..

I think this still doesnt completely answer the question the OP had unfortunately. Which I read as, Being that there is no atmosphere how can a parachute be successful? If you were to try and use a parachute to slow something down in space, would it work? My understanding is that it would not because there is nothing there to slow it down as far as air/gas. Its just space. So wouldnt that apply to mars as well?

Interesting question

reply to post by SamLuv


Actually, we did answer it. Try reading the responses a few more times.

Originally posted by AkumaStreak
Mars has a thin atmosphere. The last rovers were light enough that they could hadle impact after atmosphere drag/use the impact and bounce technique you mentioned. The latest rover is around the size of a VW bug and weighs more, so a different method was needed.

The thin atmosphere provided enough drag for the parachute... everything worked great.

edit on 8/11/2012 by AkumaStreak because: (no reason given)

That makes sense, but what happened when the rocket/sky crane phase kicked in? It seems that would cause the chute to get caught up in the mix even if it was automatically released.
EDIT- Nevermind, I just saw Spirit Horses link with the hard shell thing on its back.

Originally posted by SamLuv
I think this still doesnt completely answer the question the OP had unfortunately. Which I read as, Being that there is no atmosphere how can a parachute be successful? If you were to try and use a parachute to slow something down in space, would it work? My understanding is that it would not because there is nothing there to slow it down as far as air/gas. Its just space. So wouldnt that apply to mars as well?

Interesting question

Probably what the parachute is made of could "catch" some of the carbon dioxide/nirogen/etc.
Also the velocity and altitude at which it is deployed, since the propulsion systems were designed to operate after a descent to the surface, the parachute would only slow it down, exactly what it needed to do.

reply to post by Trublbrwing


Watch "7 Minutes of Terror" on YouTube. All descent and landing questions answered. It's only like five minutes... nice CGI of space to landing procedure.

First of all, there is enough of an atmosphere on Mars for a parachute to work a little bit -- but even with the chute, this rover was still falling more than 1000 mph. What I mean is the chute does NOT slow it down so it's just "lazily floating" -- it is still going quite fast after the chute has done what it can.

Secondly, there WERE parachutes used in the old (air bag) system to initially slow down the spacecraft a bit. The older rovers, Opportunity and Spirit, both used parachutes, along with the air bag.

Lastly, this Rover (Curiosity) was too big and heavy to use that same airbag system. They could not make an airbag system tough enough to withstand this larger rover, so they used a retro-rocket system to land.

Were supposed to believe this thing was traveling at 1000 mph before retro ro ket fire, yet were supposed to believe airbags were used to cushion the impact at such a speed for previous rovers?

Does not compute

Originally posted by Soylent Green Is People
but even with the chute, this rover was still falling more than 1000 mph.

The chute slowed the rover down to about 200 mph

Originally posted by phroziac
Were supposed to believe this thing was traveling at 1000 mph before retro ro ket fire, yet were supposed to believe airbags were used to cushion the impact at such a speed for previous rovers?

Does not compute

Its wasnt travelling at those speeds, the martian atmosphere alone can slow to craft down to about 500mph, then chute slows it down to 200 mph. Even though this was the first time they used the skycrane idea, it wasnt the first time to have used rockets to decelerate.

So yes.... DOES COMPUTE

reply to post by Kr0nZ


Thanks for the correction

And, as you implied, the airbag system also used retro rockets (as part of the back shell assembly) to slow the craft down prior to the airbag (which was hanging below) being cut loose.

Spirit and Opportunity landing video:

Originally posted by Trublbrwing
It has always been my understanding that Earth was the only planet with air on the surface

Where in the solar system would you get an understanding like that? You could say Earth is the only planet where you can breath an earth-like atmosphere, but all the planets have atmospheres, and none of them are identical to Earth's. Some like the one on Venus are quite dense. Others are very thin. But they all have an atmosphere.

Mars' atmosphere is about 1% the density of Earths atmosphere which is certainly dense enough for a parachute to work, though not a parachute designed to work on Earth. You have to specially design the chute to work on Mars.

After something shoots off into space, before it lands on another planet, is it going up or down?

NASA sending a rover to mars? Having it safely land and beam back visible images? Just laughable!!
You have all been duped.

Not only there is enough atmosphere on Mars to inflate a 'chute, but there is enough of it to require a heat shield on re-entry.

If the OP thinks that the Earth is the only body in the Solar System with an atmosphere, he seriously needs to review his knowledge of astronomy. Venus has an atmosphere, Mars has an atmosphere, and even Saturn's moon Titan has an atmosphere. en.wikipedia.org...

Originally posted by AkumaStreak
reply to post by SamLuv

 

Actually, we did answer it. Try reading the responses a few more times.

edit on 8/12/2012 by AkumaStreak because: (no reason given)

Well...you didn't in fact.

OP asked HOW such a reportedly thin atmosphere works with a parachute system...this hadn't been answered.

Mars atmosphere is reported to be 100 time thinner or less dense than on Earth...logically, one would expect a parachute system to be 100 time LESS effective as a fall arrestor on Mars.

To obtain the same or similar stopping performance from a parachute on Mars, it would have to be 100 times larger than an Earth parachute, in order to intercept enough gas to achieve the same arrest performance.

Come to think of it, the Aero-braking using a heat shield setup on the mission, would suffer the same problem as the parachute setup, meaning it too would be 100 times less effective at slowing an object hitting the Martian atmosphere than the same object being slowed within Earth's atmosphere.

The fact that rocket engines were used to cause the rover and platform to hover and be lowered to the surface over the last 70 - 80 feet wasn't the question.