Curiosity, the intrepid Mars rover, has been shuffling along the surface of the fourth planet from the sun since 2012. Being a Mars rover is lonely work, but scientists are working hard to send over some robot friends in the future. In order to land any new robo-buddies safely, a collaboration of scientists has developed an innovative robot hang glider prototype: MARSDROP.
The scientist behind the idea is Rebecca Williams of the Planetary Science Institute (PSI). To get the parachute idea off the ground (and floating in the air) she collaborated with Matthew Eby of the Aerospace Corporation and a team of engineers at NASA's Jet Propulsion Laboratory.
If deployed correctly and at the right time, the Mars parawing should prevent any crash landings. The parawing will deploy 6.5 kilometers above the surface of Mars. This will help the heltering probe to slow down from 7,000 meters per second to under 7.5 meters per second. The whole process should take about ten minutes.
Landing on Mars is no mean feat and there are various challenges to for which to account when attempting touchdown. The atmosphere is thinner than on Earth, so there is less friction against the motion of a landing probe. The British-built Beagle 2 probe may have fallen victim to this: on Christmas Day in 2003, the craft crash landed on Mars instead of bouncing on its airbags. Later analysis postulated that the low atmospheric density on Mars may have activated the parachute and airbags too late.
Curiosity overcame this challenge: it was lowered onto the surface of the "red planet" on cables. The lowering was perfomed by a rocket-powered sky crane. It was certainly a nail-biting experience for the scientists involved; this was the first time such a maneuver had ever been attempted on another planet.
But a sky crane is proabably not the most cost-effective or stress-free landing assistant. In contrast, the cost of the parawing is estimated to add only 5% to that of current Mars missions, making it a relatively cheap project. "MARSDROP is a cost-effective way to double or triple the number of Mars landers for each mission opportunity," PSI representatives wrote in a mission description.
The grand plan is to eventually send a carrier craft to Mars. Two adventurous microprobes would be released from the craft and would use MARSDROP parawings to glide safely to the planet's surface. The microprobes' smaller sizes would allow them to hop to places that the bigger rover, Curiosity, is too cumbersome to reach. These include volcanic regions, canyons and glaciers, for example. The prospect of landing in new, unexplored regions makes this project notably exciting.
If this first prototype is successful then similar missions could be made to land probes on the surface of planets with atmospheres thicker than that of Mars; turbulent Venus, for example, or Saturn's moon Titan.
Schematic of the MARSDROP landing sequence via Planetary Science Institute by Matthew Eby