Question - What's the Smallest Re-Entry Vehicle Possible?

sanman · 2012-02-23 22:14:25

Hi everyone,

I have a question - what's the smallest unmanned entry vehicle possible for descent from Martian orbit to the surface using an aeroshield and parachute?
What kind of mass and dimensions would be feasible for a minimal payload?
Do you think 10cm wide is too small? How about 5cm wide?
5 kg? 2 kg?

What's the smallest you can go, before weird problems of slipstream turbulence and cross-winds cause too much difficulty in targeting a landing zone?
The landing zone I was thinking of was a fairly large one - the Hellas Basin - and so I'd imagine it wouldn't be too hard to hit from a polar orbit.

The payload merely has to be able to measure ambient atmospheric pressure and water humidity on the surface in Hellas Basin.

Any useful feedback is appreciated.

SpaceNut · 2012-02-24 19:54:14

I was wondering the same thing over on the MarsDrive site with regards to launching a cube sat plus landing apperatus to make it land safely.

JonClarke · 2012-06-11 22:19:02

The Deep Space 2 probes massed 2.4 kg. Although they failed they show that it is possible to have an interesting and useful minimal surface mission in the nanosat class http://en.wikipedia.org/wiki/Deep_Space_2

louis · 2012-06-12 02:21:50

JonClarke wrote:

The Deep Space 2 probes massed 2.4 kg. Although they failed they show that it is possible to have an interesting and useful minimal surface mission in the nanosat class http://en.wikipedia.org/wiki/Deep_Space_2

But haven't we got Mars satellites in orbit? I imagine small devices would be able to speak to the satellites that then relay info back to Earth.

The smaller the load, the more impact it can sustain I would imagine e.g. if you have a 2 kg wrapped up in 3 kgs of sophisticated wadding. Or can you do a last minute mini launch before you hit the surface, so landing speed is really slow.

Rune · 2012-06-12 07:39:27

The smaller you go, the better your ballistic coefficient you get, so lower terminal velocity. Make it feather-like, and you need no parachute. A few grams of carbon fiber with a few tens of centimeters of diameter would land pretty softly on their own. So no lower boundary, a penny-sized piece of carbon-carbon would land much easier than MSL.

What could you do with that, now that's another question (my answer is very little, since a comm system capable of reaching orbit is too heavy to fit, never mind sensors). But a paper plane can theoretically survive earth reentry if the paper can survive the thermosphere.

Rune. They tried that from ISS, actually, though I heard no more about it.

JonClarke · 2012-06-12 23:30:22

louis wrote:

But haven't we got Mars satellites in orbit? I imagine small devices would be able to speak to the satellites that then relay info back to Earth.
The smaller the load, the more impact it can sustain I would imagine e.g. if you have a 2 kg wrapped up in 3 kgs of sophisticated wadding. Or can you do a last minute mini launch before you hit the surface, so landing speed is really slow.

You might not want it to be slow - the DS-2 probes were penetrators after all.

Not sure whether the were meant to communicate directly to Earth or via a relay. Relay would be easier, I would have thought. There was MGS already in orbit and of course MCO was supposed to be there as well.

SpaceNut · 2013-12-07 17:49:39

There has been quite a few cubesats launched and here is another that is quite interesting.

NASA's smartphone cubesat launched from MARS last month phones home

The mini satellite literally uses a smartphone as a brain, encased in a cube 4 inches square weighing a mere 2 pounds. It’s part of NASA’s long-range mission to see how well off-the-shelf commercial components perform in space, allowing the space agency to launch satellites at a fraction of the previous cost.
PhoneSat 2.4 is the first of its kind to use a two-way S-band radio, NASA says, allowing engineers to command the satellite from Earth.

http://spaceref.com/nasa-hack-space/sma … -home.html

Last edited by SpaceNut (2013-12-07 18:19:56)

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#1 2012-02-23 22:14:25

Question - What's the Smallest Re-Entry Vehicle Possible?

#2 2012-02-24 19:54:14

Re: Question - What's the Smallest Re-Entry Vehicle Possible?

#3 2012-06-11 22:19:02

Re: Question - What's the Smallest Re-Entry Vehicle Possible?

#4 2012-06-12 02:21:50

Re: Question - What's the Smallest Re-Entry Vehicle Possible?

#5 2012-06-12 07:39:27

Re: Question - What's the Smallest Re-Entry Vehicle Possible?

#6 2012-06-12 23:30:22

Re: Question - What's the Smallest Re-Entry Vehicle Possible?

#7 2013-12-07 17:49:39

Re: Question - What's the Smallest Re-Entry Vehicle Possible?

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