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#1 2012-02-23 22:14:25
- sanman
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- Registered: 2012-02-23
- Posts: 27
Question - What's the Smallest Re-Entry Vehicle Possible?
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.
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#2 2012-02-24 19:54:14
- SpaceNut
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- From: New Hampshire
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Re: Question - What's the Smallest Re-Entry Vehicle Possible?
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.
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#3 2012-06-11 22:19:02
- JonClarke
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- From: Canberra, Australia
- Registered: 2005-07-08
- Posts: 173
Re: Question - What's the Smallest Re-Entry Vehicle Possible?
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
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#4 2012-06-12 02:21:50
- louis
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Re: Question - What's the Smallest Re-Entry Vehicle Possible?
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.
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#5 2012-06-12 07:39:27
- Rune
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- From: Madrid, Spain
- Registered: 2008-05-22
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Re: Question - What's the Smallest Re-Entry Vehicle Possible?
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.
In the beginning the universe was created. This has made a lot of people very angry and been widely regarded as a "bad move"
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#6 2012-06-12 23:30:22
- JonClarke
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- From: Canberra, Australia
- Registered: 2005-07-08
- Posts: 173
Re: Question - What's the Smallest Re-Entry Vehicle Possible?
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.
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#7 2013-12-07 17:49:39
- SpaceNut
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Re: Question - What's the Smallest Re-Entry Vehicle Possible?
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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#8 2026-11-07 07:50:27
- tahanson43206
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Re: Question - What's the Smallest Re-Entry Vehicle Possible?
This topic showed up in a search for topics about re-entry. It seems to me that Rune from Madrid, Spain answered the opening question pretty well.
The topic trailed off shortly after ...
There's not much that can be done with a feather now (in 2026) but nanotechnology could change that.
This topic might have a chance to grow a bit if the wording of the title were changed slightly.
Just changing the title from "Possible" to "Practical" might help.
The need to return individual humans from orbit has not yet been met with proven systems, but there ** has ** been some thought given to the problem.
(th)
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#9 2026-11-07 08:22:29
- NewMarsMember
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- Registered: 2019-02-17
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Re: Question - What's the Smallest Re-Entry Vehicle Possible?
This post is offered in recognition of a contribution to this topic by Rune of Madrid, Spain, in 2012.
Rune offered the suggestion that a feather might survive re-entry to Earth from orbit.
Rune from Madrid, Spain, showed up in a search. His posts occurred in 2012. He suggested a feather might survive re-entry from orbit around the Earth. Humans have put a lot of material into orbit and much of it eventually falls back to Earth. It would be difficult to track an object as small and light weight as an experiment, but it might survive and be memorialized as "Rune's Feather".
This topic could actually serve as the starting point for an experiment to see if a very light weight device with communications capabilities might survive re-entry from Earth orbit.
Update: Actually, we already have plenty of samples of meteors that survived passage through the Earth's atmosphere, but only a small part of such meteors actually survived to become meteorites. I think Rune's idea was to see if something about the mass and shape of a feather might survive re-entry without significant loss of mass.
This would be an appropriate topic to report experiments along these lines.
There might even be a competition to see who could design a system that can survive re-entry from Earth orbit with the highest proportion of mass surviving from the starting value.
Rules might include a definition of minimal functionality for communication.
Special categories might include navigation. A very light weight object might be able to steer itself during re-entry, and then travel great distances with moving air in the normal distribution of air on Earth, from the Equator to points further North.
(th)
Last edited by NewMarsMember (2026-11-07 08:30:25)
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#10 2026-11-07 08:37:07
- GW Johnson
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Re: Question - What's the Smallest Re-Entry Vehicle Possible?
We have already seen the low ballistic coefficient effect with the debris from Columbia strewn over Texas from Dallas towards Tyler. That was where plastics from the cockpit, uniform patches, and some human remains fell, all showing signs of heat, but not burnt. It broke up during ship's peak heating at the Texas/New Mexico border. The lower coefficient stuff hit nearer Dallas, the high coefficient stuff nearer Tyler.
GW
GW Johnson
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"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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