Fly Over Mars... in a Robotic Balloon

Roland Piquepaille writes "A Californian company, Global Aerospace Corporation (GAR), is developing remote-controlled balloons for the NASA Institute for Advanced Concepts (NIAC). BBC News Online reports that their goal is to send these balloons carrying robots and cameras to explore Mars skies. But it's not for a near term future. The robotic StratoSail will have a stabilizing wing suspended several miles below it. It will be able to stay above Mars for months. It will send robotic probes to monitor the surface and minilabs to carry out experiments. This overview contains more details, references and images about the StratoSail."

Comments

Re:Dependence on atmospheric pressure

[alfredw]

We certainly know a bit about the Martian atmosphere... Both the Spirit and Opportunity rovers used it to aerobrake before deploying their parachutes. Certainly not detailed knowledge, but enough to make something like this (which is self-correcting if it gets too high) workable.

Re:Dependence on atmospheric pressure

[Cyclotron_Boy]

Yeah, and this is actually an old idea that was used extensively by the Soviets during their push for planetary exploration. Since the atmosphere of Venus was so hot and dense, they were able to float the balloons with extremely heavy loads. The scheme worked well during the Venusian "night," until the sun came and expanded the volume of gas in the balloon, bursting it. The idea for balloons on Mars has been "floated" before, but it looks like it just might happen this time...

On Mars' Atmosphere, Scientific Data

[dekashizl]

Source: Calvin J. Hamilton, http://www.solarviews.com/eng/mars.htm:

Atmosphere

The atmosphere of Mars is quite different from that of Earth. It is composed primarily of carbon dioxide with small amounts of other gases. The six most common components of the atmosphere are:

• Carbon Dioxide (CO2): 95.32%
• Nitrogen (N2): 2.7%
• Argon (Ar): 1.6%
• Oxygen (O2): 0.13%
• Water (H2O): 0.03%
• Neon (Ne): 0.00025 %

Martian air contains only about 1/1,000 as much water as our air, but even this small amount can condense out, forming clouds that ride high in the atmosphere or swirl around the slopes of towering volcanoes. Local patches of early morning fog can form in valleys. At the Viking Lander 2 site, a thin layer of water frost covered the ground each winter.

There is evidence that in the past a denser martian atmosphere may have allowed water to flow on the planet. Physical features closely resembling shorelines, gorges, riverbeds and islands suggest that great rivers once marked the planet.

Temperature and Pressure

The average recorded temperature on Mars is -63 C (-81 F) with a maximum temperature of 20 C (68 F) and a minimum of -140 C (-220 F).

Barometric pressure varies at each landing site on a semiannual basis. Carbon dioxide, the major constituent of the atmosphere, freezes out to form an immense polar cap, alternately at each pole. The carbon dioxide forms a great cover of snow and then evaporates again with the coming of spring in each hemisphere. When the southern cap was largest, the mean daily pressure observed by Viking Lander 1 was as low as 6.8 millibars; at other times of the year it was as high as 9.0 millibars. The pressures at the Viking Lander 2 site were 7.3 and 10.8 millibars. In comparison, the average pressure of the Earth is 1000 millibars.

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For news, status, updates, scientific info, images, video, and more, check out:
(AXCH) 2004 Mars Exploration Rovers - News, Status, Technical Info, History.

Re:Good and bad

[Capt'n Hector]

As long as the pressure from the inside is the same as the pressure on the outside, we're good to go. Assuming an ideal gas, this means the number of particles on the inside of the baloon is equal to the number of particles on the outside of the baloon. What we are really concernd about is the composition of the atmosphere, not the density. The baloon's size therefore is not related to the atmospheric pressure but rather the molar mass of the atmosphere. And as you said, gravity is weaker, so if anything I bet the baloon would be smaller than it has to be on earth.

Re:We can't land a big air bag on Mars

[dekashizl]

Err... Not only can we land an airbag on Mars, but we just did it successfully. Twice.

Re:Atmoshperic Density

[CComMack]

For hydrogen to explode, it needs to be in the presence of oxygen.

This is much less a concern in the Martian atmosphere, which is 95% corbon dioxide, as opposed to Earth's 80%-20% nitrogen-oxygen mix.

As for storage and transport, hydrogen can either be well contained (rocket fuel rarely explodes prematurely these days), or generated by a chemical reaction upon arrival (anyone remember what you get from adding a metal to acid from middle school chemistry? Though I'd imagine the medium of choice would likely be something like hydrogen peroxide. IANA Chemical Engineer.)

Fly over now

[IPFreely]

You can take virtual flyovers of Mars now. A neat website hosts virtual, controlable Mars flyovers of famous sites, including the lander sites. MarsQuestOnline has several Mars virtual flyovers, and lots of other good Mars stuff. check it out.

Re:Dependence on atmospheric pressure

[mikerich]

I would think that the success of this would depend on our knowledge of the density of the Martian atmosphere. Do we know much about this?

We know quite a lot.

The Soviet Mars 6 probe recorded atmospheric measurements all the way to the surface, as did the two Viking probes.

And it is routine to use measurements of the strength of signals from orbiters to measure atmospheric density. As the probe slips behind the planet, any atmosphere will interfere with the signal strength. Measure it finely enough and you can plot the varying density with altitude.

This isn't the first proposed balloon on Mars. the Soviet Union and France planned a mission for 1992, which was then slipped to 1994 then to 1996 and finally cancelled. The mission would have comprised of a heavy orbiter which would have acted as a communications relay and survey craft, a number of very small landers and/or penetrators and a pair of balloons.

The balloons would have used a combination of helium and solar heating to gain lift. The helium would provide most of the lift, the warmth of the Sun would give it bouyancy during the day. As it warmed, it would rise and drift along providing an almost constant aerial survey.

In the evening, as it cooled, the balloon would sink back to the surface - the helium would prevent the balloon snagging on the surface and keep the antennae upright. Meanwhile, instruments loaded into a long 'snake' slung below the balloon would be making surface measurements and inspecting the geology.

The balloon was tested on Earth and proved to be highly successful, it's a tragedy that the collapse of the Soviet Union prevented it flying.

Best wishes,
Mike.

prior art

[savuporo]

A mention of prior art in balooning the other planets would be in order. Many people arent aware of the fact that Russian Venera program, what later become Vega, successfully flew two balloons in Venusian atmosphere in 1984.
Geoffrey Landis has a couple very thought-provoking papers on his website, regarding possible further developments of atmospheric flight on both mars and venus, and possibilities for human living in upper atmosphere ....

Re:What about the pending helium shortage?

[Pherry]

A quick check in the Wikipedia, under the ocurrance section for Helium reassures me a little "Helium is the second most abundant element in the universe"

It's just a matter of patience ;o)