Robert Zubrin's Mars Gashopper Airplane

Fraser Cain writes "Universe Today has a story about Robert Zubrin's (Mars Society President) Martian Gashopper Aircraft proposal to NASA. It uses solar power to liquefy carbon dioxide and then use it as a propellant to take off, fly hundreds of km above the surface of Mars like an airplane, and then land vertically again."

Comments

Here and now?

[FractiousWeasel]

Is it possible to use this technology here on Earth? We certainly have the carbon dioxide for the fuel. Are higher temperatures or gravitational forces a showstopper?

Re:Here and now?

[stratjakt]

The limiting feature of the gashopper is the electricity required to pressurize and heat the carbon dioxide propellant. This process consumes a lot of power, and the gashopper would need more than a month using its solar cells to refuel and recharge its batteries before it could take off again.

I guess if you only travelled a few hundred yards a month, it might work.

I'm pretty sure gravity is an issue, though. Gravity's a real bitch. Newton should never have invented it. Or he should have at least patented it so noone could use it.

Re:Here and now?

[Clay Pigeon -TPF-VS-]

The Carbon dioxide is much more concentrated on Mars than on Earth. It would take a lot longer to get enough for fuel, and you would need more propellant to overcome Earth's larger gravity.

Re:Here and now?

[InfiniteWisdom]

I don't think CO2 is essential to the system... it just happens to be the most handy gas available on mars. Its really like a VTOL aircraft with jet engines except that the gas is heated electrically rather than by burning fuel. An earth-based gashopper would just use air.

Re:Here and now?

[r00zky]

> The same 50 kg would weigh about 41 lbs on Mars.

Do martians use the imperial system now?

For the imperial impaired (like me) 41 lbs == 18,6 kg

Interesting

[over_exposed]

While the mobility is an interesting concept (being able to move 100+ km at once), how does this change the vehicle's ability to analyze more area? The other crafts "can only examine a few square metres of ground"... at a time. But then it moves and does it again... The only differences I see is that the gashopper does it's analysis of the "few square metres of ground" then hops ~100km away only to analyze a "few square metres of ground." How is this spotty analysis better than continuous examination? Maybe it could be used in conjunction with other crafts of old style. The gashopper gets sent to interesting locations to determine if they should send a more traditional land-based craft? One thing is does have going for it is the ability to refuel itself.

Re:Interesting

[Egekrusher2K]

You're correct in one aspect, that it can only examine a small area at a time. However, with this new vehicle, they aren't limited to one geographical feature set. With the rovers, we are limited to flat terrain that is navigable by wheeled autonomic vehicles. With this, we can fly down to the bottom of a chasm and take readings down there, where there may be a better chance to find some sign of life (ie an area of Mars that is more well preserved than others).

Re:Interesting

[radtea]

The advantage this concept has is one of sampling scales. We know very little about Mars in terms of its global minerology, etc. I'd say "geography" and "geology" except some pendant would insist that the correct term is "areology" or "gnu/areology" or something.

In any case, landing in one or two spots tells us about those spots, but we'd really like to know about over overall structure of the planet. On Earth, for example, we have big structures like the Canadian Shield. Landing on one spot and then moving around will tell you that, yep, you got granite over here, too. What we'd like to do is sample on a coarse scale, so we could see that a few 100 km away we've got completely different geology.

That's where the gashopper comes in. It's an extremely clever concept. The Martian atmosphere is mostly CO2, and the cycle of boost, glide, land and recharge could go on for a long time. It's a great way to explore a new planet on a scale that's never been done before.

--Tom

Nose full of "science"

[Jonboy X]

I love that diagram on the website. Future press conference transcript excerpt:

Reporter: "Yes Mr. Zubrin, it's certainly an impressive design. What will be in the nose of the craft?"

Mr. Zurbin: "As you can see from this diagram, the nose of the craft will contain "science". Next question."

Liquifying CO2?

[crovira]

CO2 sublimates, doesn't it? Might not make any difference for their application though.

Its a good idea NOT to have to import hydrocarbons as the nearest filling station is back here, far far away. CO2 is pretty plentiful.

The wings holding the solar panels would have to be self-cleaning though.

Re:Liquifying CO2?

[Cid Highwind]

CO2 sublimates, doesn't it?
It does under Earth's amospheric conditions. You can liquefy CO2 by putting it under high pressure (5+ atmospheres, IIRC). When they release the liquid CO2 it'll probably produce gas and small crystals that will sublimate away, like what happens when you discharge a CO2 fire extiguisher on Earth.

It would be neat to watch a rocket powered aircraft that trails dry ice snow instead of smoke and flames...

Re:RTGs?

[Anonymous Coward]

Hope you managed to get your knee out from under your desk before it jerked. Patellar cartilage takes a long time to heal.

You need to learn a little about how RTGs work and how ridiculously clean and safe they actually are.

Look at the diagram in the article

[stratjakt]

This thing is equipped with a warhead of PURE SCIENCE!

Re:why even worry?

[spazoidspam]

Gee, that says a lot about humanities approach to global issues: "It won't affect us, so why not?" Not only are we ruining our OWN planet, but now we're going to ruin another one?

How will this hurt the planet? All they are doing is using solar energy to compress CO2 into liquid form, then heating it back up again to make it rapidly expand back into gas form, giving thrust. This is no different then compressing a bunch of air here on earth and then spraying it back out again. I dont see how this could possibly hurt the enviroment.

About Time

[mordors9]

Them martians have been scaring people on this planet for years with their UFOs. Now it's our turn.

Re:why even worry?

[Valar]

Look, your "logic" has no place here. This is the land of knee jerk, uninformed, karma whoring comments. Please, take your "understanding of concepts" elsewhere.

Am I the only one...

[Fizzl]

Who thinks the guy looks like a prototype of a hung-over russian mad scientist?

(No offence to any russian mad scientist having hang-over mind you....)

Re:why even worry?

[krel]

Your objection to "ruining" is undermined when the planet is already ruined. It's a long-held theory that solar wind blew the atmosphere right off the planet, making it totally uninhabitable. As an added bonus, there's no more geothermal energy to gain from the planet and it's too far away from the sun to farm a significant amount of solar energy, so one could say definitively that mars is here and forevermore useless.
On a more general note, it frustrates me whenever I hear people comment that we shouldn't pollute the moon, or throw nuclear waste in to the sun -- as if these places had a delicate ecosystem that some human-defined "pollution" would upset. There is so much room in the universe; in the end, only loony environmentalists care whether a hundred thousand tons of used beanie babies end up "recycled" on earth, or dumped on the moon.

Re:RTGs?

[Dolphinzilla]

RTG's don't release any chemical compounds, they are only used as heat sources (in this case heating banks of thermocouples to generate electricity) - the fuel pellets are usually bound in plastic to make handling safer.

Don't dream of Mars planes yet

[killbill!]

I remember some dude that had created Mars planes on a simulator, using real NASA-supplied data.

His findings: low gravity and ultrathin atmosphere are bitches.

For one, the ultrathin atmosphere (air density 1% of the Earth's) requires huge wings and a very high speed to generate enough lift.

Taking-off and landing are almost impossible. The planes needs a speed of 400 knots to take off. Landing is very... hard because low gravity prevents you from using brakes, and low air density from using reverse thrust.

Of course, the Gashopper isn't supposed to take off or land (it could not anyway). However, it'd still need massive horsepower and huge wings - all of which make it hard to cram the Mars plane into a space probe.
Bottom line: if the plane has been successfully tested on Earth, it is unlikely to work on Mars.

Disclaimer: I am not a Mars aerospace engineer. But that guy's findings were definitely interesting.

He's not the only one....

[carambola5]

Last Friday (Nov. 19) was a big milestone for many small companies like Robter Zubrin's. This is when NASA announced its 2004 SBIR Phase I awards. And yes, this Gashopper is one of them.

Check them all out at: http://sbir.gsfc.nasa.gov/SBIR/sbir2004/phase1/awa rds/2004topic.html There's really some innovative stuff going on. Also, to the future rocket scientists out there: if you want to work in aerospace, this is an excellent site to find small companies doing NASA subcontracting.