Martian Gashopper Aircraft

Palomar · 2004-11-25 18:34:07

Whos]http://www.universetoday.com/am/publish/mars_gashopper.html?25112004]Who's that guy?

*I can't believe this hasn't been discussed or posted about previously, but I did some earnest hunting with the Search feature.

Well...looks like Dr. Z isn't about to rest on his laurels any time soon.

Zubrin's company, Pioneer Astronautics, has already done a significant amount of testing and research for the concept, and they developed a prototype gashopper for NASA's Jet Propulsion Lab in 2000.

Cool. I suppose Dr. Jeffrey Bell has already given the thumbs down. :-\

--Cindy

Shaun Barrett · 2004-11-25 20:17:33

A very nice idea!
Dr. Z always impresses me with his 'let's get on with it' attitude. As you say, he never seems to rest.

The biggest problem to be overcome, I think, will be something that was glossed over pretty quickly in the article, and that is "hazard avoidance".
Every manoeuvre made by the MERs is planned, discussed, calculated, etc, before it's executed because of the time-lag between instructing the rover to move and finally seeing what happened after the event. In a very real sense, once the command to move is sent, we're driving blind. Admittedly it's a calculated and, so far, very successful strategy but it is an act of faith to some extent; a little like looking down the road from your parked car, figuring out you should be able to proceed safely for a distance of about 50 metres, then closing your eyes and hitting the accelerator!
And the MERs have the advantage that they can see where they'll be going.

This gashopper will be moving to brand new places it's never seen before, and landing there, without detailed input from scientists on Earth - unless it can hover over a potential landing site long enough to get a picture to JPL (or wherever) and wait for a yea or nay to come back.

I'm definitely not trying to rain on Dr. Z's neat idea; far from it, I'd love to see it up and working on Mars. It's just that we'll be needing a degree of onboard artificial intelligence I'm not sure we have the technology for just yet.
However, I'll be more than happy for someone to explain to me I'm way behind the times on this and that the technology is available and mature enough to do the job.

[Ideally, of course, we could save ourselves a lot of time and faffing around and just get on with the job of implementing Mars Direct A.S.A.P. We could have the first Hab settling into the martian dirt by 2018 if we had but the will to do it.]

Palomar · 2004-11-25 20:40:21

The biggest problem to be overcome, I think, will be something that was glossed over pretty quickly in the article, and that is "hazard avoidance".
Every manoeuvre made by the MERs is planned, discussed, calculated, etc, before it's executed because of the time-lag between instructing the rover to move and finally seeing what happened after the event. In a very real sense, once the command to move is sent, we're driving blind. Admittedly it's a calculated and, so far, very successful strategy but it is an act of faith to some extent; a little like looking down the road from your parked car, figuring out you should be able to proceed safely for a distance of about 50 metres, then closing your eyes and hitting the accelerator!
And the MERs have the advantage that they can see where they'll be going.
This gashopper will be moving to brand new places it's never seen before, and landing there, without detailed input from scientists on Earth - unless it can hover over a potential landing site long enough to get a picture to JPL (or wherever) and wait for a yea or nay to come back.
I'm definitely not trying to rain on Dr. Z's neat idea; far from it, I'd love to see it up and working on Mars. It's just that we'll be needing a degree of onboard artificial intelligence I'm not sure we have the technology for just yet.

*Wow Shaun, you're absolutely right. Why didn't all that occur to me? :hm: Sure, I know how the MERs operate and etc. -- but the comparison didn't happen for me, until you pointed it all out. Definitely food for thought (understatement).

--Cindy

GraemeSkinner · 2004-11-25 22:45:38

It would be good to see how a winged flyer would react in the martian atmosphere, then we'd have a better idea if an AI system would be able to work or not. Major obstacles would already be known in advance and plotted in a flight plan so should not prove a major problem. Its the unknowns that could prove its downfall, if the gashopper was slow to manoeuvre then its AI system would have to be looking a good way ahead to look for any pitfalls. If it was flying through a valley or round a hill it may not be able to see far enough ahead to plot any avoidance manoeuvres in time.

Graeme

Rxke · 2004-11-26 02:22:04

Dr. Z... Sounds familiar...

He's that evil genius in one of the Bond films? The world is not enough?

Rxke · 2004-11-26 02:46:21

On a related note... I once downloaded a *very* interesting .pdf that dealt with gas propelled probes, fuel cell powered, in the form of little balls. They just 'hopped' around... Idea was to pack *a lot* of them and launch them, so loss of some no problem etc.

But I have been unable to find the link since. Sounds familiar to anyone? They tested the hardware in caves.

mboeller · 2004-11-26 03:32:29

You can find the complete report about the Gas Hopper at the homepage of Pioneer Astronautics (together with a lot of other very interesting reports by the way) :

http://www.pioneerastro.com/MGH/mgh.htm … H/mgh.html

http://www.pioneerastro.com/MGH/Gashopp … Gasshopper Final Report.Doc

Rxke · 2004-11-26 06:05:06

Shaun,
re: the hazard avoidance...

I guess it's quite straightforward to implement... Using radar and gyro's and some contact switches.

if you use three landing legs with 'contact-switches... and go down, slowly, using coarse radar, it steers you to a relatively level spot... slower and lower all-but hovering... Contact! Now if there's a big boulder or pit, on the otherwise quite level plane, only some of the legs will give contact, and the ship will start going off-axis. It starts to tilt. Just insert a switch that says: "if off axis for more than xx degrees, Then briefly increase gas exhaust, to give it a little mini-jump, away from that boulder-pit..."
repeat that 'dance' until you find a spot that's level enough. and cut the engine.
And hope you've not run out of gas before you found the sweet spot, of course.
But I guess mission planners will start first landing on a known flat place (like spirit/opp landingplaces) then hop to another flat one, then gradually go to a bit riskier terrain... untill they decide... "hmmm. That last one was too close for comfort, let's stick to terrain type XYZ, from now on."

Shaun Barrett · 2004-11-26 07:55:42

An impressively simple system, Rik.
I don't mean 'simple' as in dumb, I mean 'simple' as in fewer things to go wrong and therefore better. And it might well work - especially if something like your incremental risk strategy is employed.
As I've said, I want it to work! If we can't have a real geologist on the surface, this would be a good surrogate.
How much developmental lead-up time do you think it would take to get the AI system reliable enough to risk $300-400 million on?

Rxke · 2004-11-26 09:54:06

How much developmental lead-up time do you think it would take to get the AI system reliable enough to risk $300-400 million on?

Good point. It-s high risk... Better make it as low risk as possible...

I guess Dr. Z is already halfway there... Test the 'naked' hardware (lander/hopper system w/o expensive sciencepackage) till it breaks on Earth, first on flat terrain, later on more rugged stuff.... Then learn from what went wrong, repeat...

How much time? no idea. But he might give a call to the Armadillo guys, they've been working on just such control software, to put their suborbital RLV down, nose up.

Palomar · 2004-11-26 10:04:20

*Every time I think of this gashopper (or is it supposed to be 2 words -- gas hopper?...oh well, the article crams it together, so the heck with it) I can't help thinking of that scene in Star Wars: The Empire Strikes Back where that black sinister-looking probe descends down into snowdrifts, looking for Luke Skywalker (?), then gracefully picks itself up again (with almost octopus-like movements) and jettisons on over the snow.

Yeah, I know Dr. Z's plan doesn't have sinister connotations...

But Rik, we still have that time lapse between Earth-Mars communication. Maybe I'm missing something in your response. (Oh...and sorry if I confused you in that other thread, regarding your current sig).

--Cindy

Rxke · 2004-11-26 10:10:38

But you don't need no Earth/Mars comm, it's a simple hardware feedback loop, so independant for the last few meters/centimeters...

Palomar · 2004-11-26 10:22:22

But you don't need no Earth/Mars comm, it's a simple hardware feedback loop, so independant for the last few meters/centimeters...

*I see. Sorry for the misunderstanding.

--Cindy

GraemeSkinner · 2004-11-26 10:23:03

If the gashopper does not need to worry about whats in front of it, just where its going to land, then the AI required should not be a major issue. You could use the system Rxke suggested and add a ultrasonic unit to each leg, I think I could even put the electronics together for that :;):

Graeme

universetoday · 2004-11-26 11:10:04

Thanks for the additional links and comments. I made a few minor changes to the article.

Fraser Cain
Publisher
Universe Today

Palomar · 2004-11-26 11:29:52

Thanks for the additional links and comments. I made a few minor changes to the article.
Fraser Cain
Publisher
Universe Today

*Hi. Your web site is fantastic. I check it at least twice a day, generally.

--Cindy

universetoday · 2004-11-26 12:35:23

Well, thank you very much, I really appreciate that. Of course, I only really update it once a day. In the mid morning here on the West Coast.

Shaun Barrett · 2004-11-27 08:04:34

Nice of you to drop in Fraser!
By the way, in that photo in the "About Fraser Cain" section of your site, who's the old guy behind you in the white shirt?
???

SpaceNut · 2004-11-29 08:45:30

Interesting how compressed gas (air of any kind) can be used.
I would assume that the solar cells are on the wings and that the storage tanks are there as well. Would not take to much to modify the unit for manned flight control.

RickSmith · 2007-03-31 20:03:31

Rather than using 3 legs I would use 6.

Radar on board finds a generally flat area and it goes into vertical landing mode (like a jump jet). As it decends the legs start to touch down on rocks and the like. Give each leg a 50 to 70 cm of 'give'. If at least 2 legs have not touched down on the other side of the plane by the time it has used most of this give, then rise up a bit, move forward a bit and try landing again.

Extra legs make it a lot easier to find a stable landing zone. (The cost of this is the mass of the extra landing gear, but since this is mission critical I feel it is worth while.)

Warm regards, Rick.

Ian Flint · 2007-04-01 12:24:50

I think a dual mode craft (VTOL/Horizontal Flight) is too complex. They should try the gashopper concept with a ballistic hopper first. If that works move on to the dual flight mode.

GCNRevenger · 2007-04-18 13:10:01

The Martian atmosphere is about two orders of magnitude thinner than ours. This makes flying with wings (horizontal) much harder, but it also makes ballistic flight somewhat easier. Ballistic hoppers for air travel, rovers followed by trains for ground travel some day.

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#1 2004-11-25 18:34:07

Re: Martian Gashopper Aircraft

#2 2004-11-25 20:17:33

Re: Martian Gashopper Aircraft

#3 2004-11-25 20:40:21

Re: Martian Gashopper Aircraft

#4 2004-11-25 22:45:38

Re: Martian Gashopper Aircraft

#5 2004-11-26 02:22:04

Re: Martian Gashopper Aircraft

#6 2004-11-26 02:46:21

Re: Martian Gashopper Aircraft

#7 2004-11-26 03:32:29

Re: Martian Gashopper Aircraft

#8 2004-11-26 06:05:06

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#9 2004-11-26 07:55:42

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#10 2004-11-26 09:54:06

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#11 2004-11-26 10:04:20

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#12 2004-11-26 10:10:38

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#13 2004-11-26 10:22:22

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#14 2004-11-26 10:23:03

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#15 2004-11-26 11:10:04

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#16 2004-11-26 11:29:52

Re: Martian Gashopper Aircraft

#17 2004-11-26 12:35:23

Re: Martian Gashopper Aircraft

#18 2004-11-27 08:04:34

Re: Martian Gashopper Aircraft

#19 2004-11-29 08:45:30

Re: Martian Gashopper Aircraft

#20 2007-03-31 20:03:31

Re: Martian Gashopper Aircraft

#21 2007-04-01 12:24:50

Re: Martian Gashopper Aircraft

#22 2007-04-18 13:10:01

Re: Martian Gashopper Aircraft

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