USING SOLAR POWERED HYDROGEN OR HELIUM FILLED BLIMPS
North of Valles Marineris on Mars; the largest canyon system in the Solar System, lies a depression with no outflows, called Hebes Chasma. It is roughly 320 km long and 130 km wide with a maximum depth of 8 km below the surrounding plains. Its stratified and eroded geology tells a story of erosion, collapse, land-sliding and sedimentation over several epochs in Martian history. Due to lack of an outflow, in the wet days of Martian ancient past, the depressions in Hebes Chasma may have harboured long standing lakes and waterbodies for very long periods of time.
Hebes Chasma, THEMIS Infrared image
In my view, if one is interested in search for the remnants of ancient life on Mars if it ever existed, look no further than Hebes Chasma. Ancient life forms on Mars may have survived longest in the relatively protected environment of the chasma while the rest of the planet was drying out. Long standing water bodies may have made it possible for life to have evolved to creep deeper into the ravines and crevices at the bottom of the chasma before eventually dying out. In addition, the fossilized remains may have survived longer due to the relatively protected environment in its depths along the bottom of the cliff systems. Strange looking flow patterns in the deepest portions of the Hebes Chasma have many stories to tell to any visitor who gets there.
Landslides and strange flow patterns are visible in several places inside Hebes Chasma
Exploration through rovers is currently the most efficient means of exploration of Mars to study its geology and for the search of life, past or present. Rovers have moving parts and have to navigate through the toughest of the terrains with no prospect of repair on the desolate world. Moving parts and wheels negotiating through jagged terrain have a short life and at times the main limiting factor in the scope of robotic rover missions. Use of vacuum blimps has been discussed as an efficient replacement of robots on Mars. There are two main problems with this idea; the Martian atmosphere is already very thin; almost near-vacuum. Use of conventional helium or hydrogen blimps may not generate enough lift; hence the idea behind the use of vacuum. But keeping a blimp afloat containing nothing but vacuum against the crushing pressure from outside will need a much sturdier, internally supported structure. This may increase the weight of the blimp, making such a venture practically useless. Also, the dust storm on Mars may blow away the blimp and destroy it.
Hebes Chasma is a different story. Not only its sheer depth and closed environment may offer some protection against the full force of a Martian dust storm, but also the atmosphere near the floor of the Chasm may be much thicker than the outside surrounding plains, making lift using hydrogen or helium possible. Also, the extra atmosphere all the way down to the floor of the chasm may offer extra distance for more efficient aerobraking, reducing the need for retro-rockets and therefore requiring less fuel, creating extras space and weight capacity for additional instrumentations.
For a spacecraft making such a landing in the base of the Hebes Chasma, exploration of the surroundings may be more efficiently done through the use of blimps. Such blimps will be inflated after landing using liquid hydrogen bottles releasing gaseous hydrogen to fill up the body of the blimp. Use of hydrogen is safe on Mars as there is no oxygen to cause any accidents. The blimp will have solar panels embedded in its fabric and will carry instrumentation under its belly. It will be propelled by solar powered propellers, generating a speed of 5-6 kms per hour. It will explore the Martian soil using retractable telescopic tentacle-like arms. It can remain afloat a few meters above the ground for many months. In an event of a dust-storm, it may partially deflate itself and use the tentacles to anchor itself to the ground until the storm passes. Due to lack of many moving parts or any direct contact with the ground, under right circumstances, such blimps may virtually remain afloat and functional for many years, and will explore areas over thousands of square kilometers on the floor of Hebes Chasma; inspecting, collecting and analyzing specimens from the areas of interest in the deepest parts of the chasma.
(Landscape rendering derived from Google Earth. Blimp concept: Muhammad Akbar Hussain, Mareekh Dynamics)
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