[X] My Assistant

[karolp]

Hello again,

With the Martian airplane concept becoming sort of abandoned these days, I just wonder if a Martian CHOPPER was ever considered. With the capability of MRO I guess we do not need airborn instruments dedicated to imaging there. But: what about chemical measurements and "sniffing" for volatiles? Imagine something that could land at one spot found to be interesting on MRO photos and then take off and go sniffing for methane somewhere else? What do you think? Does it make any sense to you?

Regards,

Karol P.

Poland

[djellison]

I've changed the topic of the thread - you wrote it as if such a vehicle were already planned, not as if you were posing a question.

As for choppers on Mars.....I find it very hard to imagine them working....you've going to need such large blades, such high rotation, and such a small payload to get it off the ground. A balloon would make MUCH MUCH more sense to achieve the same thing and be much simpler to boot.

Doug

[Bob Shaw]

Helicopters on Titan, that's the thing. You use an RTG to generate electricity, or even a simple nuclear heater to power a Stirling engine to do the same, then you expend it in more-or-less one go, and autorotate to a landing. You wait a few days, then take off again. On Mars, Zubrin's in-situ fuelled baby aeroplane makes a lot of sense, too (perhaps more so on Titan - just bring an oxygen supply down to the surface with you and burn the air, or crack it out of water ice!). Or perhaps on Titan you could try an aerodyne, a semi-buoyant vehicle with an aerodynamic shape which flies by generating lift, then drifts down. Or...

Bob Shaw

[karolp]

Thank you for correcting me. I also thought the design would have to be modified to suit the thin Martian atmosphere. But on the other hand it is probably somewhat compensated by less gravity. I would imagine a small but well equipped payloayd attached to a fast spinning rotator. A balloon might get punctured at some point. But a RTG-powered chopper could make a significant number of lift-offs and landings followed by chemical measurements saving a lot of money on tons of landers to be placed in different areas... It is kind of neat to have the MERs able to MOVE But imagine something that could actually lift itself above the surface and FLY to sniff rocks tens of kilometers apart...

[ngunn]

Variations on the hot air balloon theme make a lot more sense For Titan as you can use the heat from the RTG directly instead of losing about 90 percent of it in a highly inefficient electric generator. However I imagine any balloon would have to be quite large in the case of Mars due to the thin atmosphere, and a hot-air one would presumably require several times the volume of a hydrogen-filled one to provide the same lift.

Off the wall query: Would it be possible (on any planet) to use focussed sunlight plus greenhouse effect to power a hot air balloon? I am picturing a double skin balloon black on the inside with the outer membrane opaque to long wavelength IR, and a large but light parabolic reflector suspended beneath.

[djellison]

Oh - I've seen pdf's and ppt's showing Mars balloons that heat up in the morning - expand, take off - drift for the day then settle down again as it cools in the evening and have an analogy to 'drag chains' to park up overnight to do overnight obs of some sort.

Doug

[ngunn]

Very interesting. How do people rate these ideas? Should they be taken seriously? I can't see any obvious reason why not. Using in-situ resources for both baloon-filling gas and power seems very appealing, almost too good to be true - but maybe it's just too good not to try?

[karolp]

Actually, balloons were not only considered. They were built by the French for the Russians but the mission ended up exploring the bottom of Earth's ocean. It it were not so, and if Mars Observer didn't fail, we would have remembered it as the first orbiter to relay data from a balloon dragging a "snake" on the surface:

"Mars Observer was also to support the acquisition of data from the Russian Mars 1994 mission through the use of the joint French-Russian-American Mars BALLOON Relay instrument."

http://nssdc.gsfc.nasa.gov/database/Master...og?sc=1992-063A

And:

"The design and utilization plans for the Mars Balloon guiderope are described with attention given to environmental and mission constraints. The guiderope is intended to enable the balloon to fly close to the Martian surface to sample the surface and near-surface atmosphere. The 'Snake' concept is described for this application which comprises overlapping cones that provide a smooth dragging surface as well as structural flexibility. A 'tail' segment of small diameter is attached to the Snake that stabilizes the guiderope with titanium shells and also serves as half of the required radar dipole antenna. A specific design is set forth for the Snake and Tail elements that provides dust-tolerant effectiveness without lubricant for the extreme conditions of the Martian surface. The resulting guiderope for the Mars 96 Balloon Mission is expected to render the exploratory mission effective."

http://adsabs.harvard.edu/abs/1992wadc.iafcY....L

[remcook]

The Mars 96 mission was supposed to have a balloon on board that Doug speaks of. According to this site http://barsoom.msss.com/mars_images/mars_r.../mer_index.html the balloon never made it to the payload. It wouldn't have made it to Mars anyway...


http://www.omnitron.net/radar/0mars.htm
http://www.springerlink.com/content/h60754884137p8k1/

[Gray]

Just yesterday I happened to see a photo of a flying machine for Mars. It was designed by Pioneer Astronomics and is called a "vertical takeoff flying machine".

http://www.geotimes.org/july06/feature_SpaceJetting.html

[ynyralmaen]

... They were built by the French for the Russians but the mission ended up exploring the bottom of Earth's ocean.

Just to be pedantic, it's often stated that Mars 96 ended up in the Pacific, but it actually came down in Bolivia or surrounding territories; several people at ESO observed it descend.

10 years may have blurred the details, but as I recall... The confusion over its final resting place is probably caused by the fact that NORAD announced it was tracking the spacecraft after it failed to leave Earth orbit, and, if I recall correctly, the US offered help to Australia if the spacecraft with its plutonium power supplies landed on their territory. They then announced that it had re-entered "safely" over the Pacific. It was later realized that NORAD had been tracking the final stage, and that Mars-96 itself had already detached and had re-entered the Earth atmosphere over the Andes. No-one offered Bolivia help with the clear-up though, and as far as I know, the debris has not been located.

It was a huge loss... the most massive interplanetary spacecraft ever launched; even exceeding Cassini's mass.

[Jim from NSF.com]

Just to be pedantic, it's often stated that Mars 96 ended up in the Pacific, but it actually came down in Bolivia or surrounding territories; several people at ESO observed it descend.

It was a huge loss... the most massive interplanetary spacecraft ever launched; even exceeding Cassini's mass.

Really? I thought its propulsion system had to be used for part of the earth escape burn. It so, any mass allocated to this, is not part of the "spacecraft" but part of the LV and therefore it wasn't "big"

[MarkL]

It was a great loss at the time, but putting it in perspective we can now fly far more advanced missions (and several of them) with a considerably lower mass budget. The lucky thing is agency-level interest in Mars was never allowed to wane (at least in NA) despite the meteoric ending for the mission. It may have given NASA and JPL more bragging rights in the end.

[MarkL]

Just yesterday I happened to see a photo of a flying machine for Mars. It was designed by Pioneer Astronomics and is called a "vertical takeoff flying machine".

It's fascinating to speculate, but helicopters are completely at the mercy of air density. They really only are marginally flyable on Earth as a narrow rotating airfoil is extremely wasteful of lift. Energy inputs are hugely out of proportion to the lift provided. As for refilling CO2 canisters with each hop, when there is a CO2 pipeline on Mars that could be a reality. Or perhaps it is more like gassing up a bottle of party soda? I'd agree that anything other than balloons or ultra ultralight fixed airfoil craft is in the realm of the most remote and fanciful speculation for commuting about Mars.

[Gray]

In addition to carbon dioxide, I suspect that device relies heavily on smoke and mirrors.




Edit:

More on the "gashopper" from the Mars Society:

http://www.marssociety.org/news/2005/0730.asp