A proposed instrumented robotic vehicle called an "aerover" would fly, roll along the ground, and/or float on bodies of liquid, as needed. The aerover would combine features of an aerobot (a robotic lighter-than-air balloon) and a wheeled robot of the "rover" class. An aerover would also look very much like a variant of the "beach-ball" rovers described in "Lightweight 'Beach- Ball' Robotic Vehicles" (NPO-20283), NASA Tech Briefs, Vol. 22, No. 7 (July 1998), page 74. Although the aerover was conceived for use in scientific exploration of Titan (the largest moon of the planet Saturn), the aerover concept could readily be adapted to similar uses on Earth.
The aerover would include three thick-walled balloons (see figure), each about 2 m in diameter. Initially, the balloons would be inflated with helium to provide lift for flight. Later the balloons would also serve as cushions for landing, as soft tires for rolling over the ground, as flotation bags for traversing bodies of liquid, and as thermal barriers to protect instrument payloads against extreme cold on the ground.
Following initial inflation, the aerover would be set free to drift at a controlled altitude, gathering images of terrain. Altitude control could be effected by (1) heating and/or inflation from a supply tank for ascent and (2) venting helium and/or turning off the heater for descent. From time to time, helium would be vented to make the aerover descend to collect ground samples by use of tethered coring modules or a landing snake. Thereafter, the aerover would make several ascents and descents to acquire additional images and samples.
Eventually, the helium supply would approach depletion; helium would then be vented gradually to effect a final descent. The residual helium in the balloons would provide cushion for a soft landing. Thereafter, the aerover would remain permanently on the surface.
Once the aerover was on the surface, the residual helium in the balloons would be replaced with ambient air. The aerover would then roll along the ground and/or traverse liquid to travel to designated sites, where it would collect highly localized images and samples.
The three-balloon design concept is a fail-safe one. The aerover would be designed so that two functional balloons would provide sufficient lift for ascent. Three balloons would afford redundancy to protect against a failure of one of the balloons. If all three balloons were intact and functioning as intended, then the aerover would have a capability for initial overinflation.
This work was done by Aaron Bachelder of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Machinery/Automation category. NPO-20609.