The mission to Mars that last century’s science fiction writers so eagerly anticipated has still failed to materialise, but this doesn’t mean that today’s scientists have completely abandoned the quest for this new frontier.
One of the problems with flight on Mars is the planet’s very low atmospheric density. Fixed wing aerial Mars rovers would have to fly at over 250 MPH just to stay aloft in the red planet’s rarefied atmosphere. This makes landing on the rocky surface almost impossible, thereby precluding sample inspection/gathering.
However, as a possible way around this, researchers from NASA and the Georgia Institute of Technology are borrowing from nature – more specifically the dynamics of insect flight – to examine the concept of building an entomopter – an insect-like robot vehicle with flapping wings.
Insect flight puzzled scientists for quite some time, but they are able to stay aloft thanks to a micro-scale vortex that is created at the wing’s leading edge during either the up or down stroke. The density of the earth’s atmosphere thus prevents flying insects from getting any bigger than small birds. However, NASA scientists believe that a robotic insect on Mars with a one metre wingspan would, because of the planet’s atmosphere, operate in much the same way as a terrestrial insect.
In addition, the gravity on Mars is only 37% of that on Earth, so an entomopter- based Mars Flyer would benefit by proportionately reduced weight, even at its increased size on Mars.
An entomopter-based Mars Flyer holds promise of not only flying slowly over the Martian landscape, but being a multimode vehicle, could land, take samples/ recharge/or communicate, and then take off to continue the survey mission. Led by Professor Robert Michelson, research at the Georgia Tech centres around a development called a Reciprocating Chemical Muscle (RCM) which is capable of generating autonomic wing beating from a chemical energy source. Through direct conversion, the RCM also provides small amounts of electricity for onboard systems and further provides differential lift enhancement on the wings to achieve roll and hence, steered flight.
In addition, Stereolithography and Fused Deposition Modeling techniques have allowed Michelson’s team to create intricate wing structures directly from computer models.
Careful attention is being paid to material selection. Resilience, stiffness in opposite planes, chemical compatibility, and ease of bonding are but a few of the points to be considered in choosing wing materials.