CubeSats, tiny satellites about the size of a loaf of bread or smaller, hold the promise of opening space up to low-budget space missions, but currently they're largely restricted to Low-Earth Orbit (LEO). To broaden the scope of these pint-sized spacecraft, NASA is developing its CubeSat Application for Planetary Entry Missions (CAPE) concept, which would see the development of miniature space probes that can be sent in fleets on interplanetary missions for multi-point sampling, as opposed to the bus-sized, do-it-all probes that are currently in service.
CAPE is the brainchild of technologist Jaime Esper at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who envisions the interplanetary CubeSat as a pair of modules similar to those used on the crew and cargo ships that service the International Space Station (ISS). These would consist of two modules weighing less than 11 lb (4.9 kg) and measuring 4 in (10 cm) on a side. The first would be a service module to power the craft, and the second a Micro-Re-entry Capsule (MIRCA) for entering the atmosphere of Mars or some other planet or moon under study.
The idea is that the CAPE/MICRA spacecraft would be carried by a mothership, which would eject them before reaching the target planet or moon. The service module would then provide power from solar panels or internal batteries and make its way to its target. Once the journey is complete, the MICRA module would separate and enter the planet's atmosphere, where accelerometers, gyros, thermal and pressure sensors, radiometers, and other sensors would send data back to the mothership.
According to NASA, the next step in the project is for the MICRA module to carry out tests later this year at Fort Sumner, New Mexico, where it will be dropped from a high-altitude balloon at an altitude of 18.6 mi (30 km) and accelerate to up to Mach 1 in free fall. Esper says that he hopes to send the MICRA module to the ISS as early as 2016, so it can be tested under actual space and re-entry conditions.
"The balloon drop of MIRCA will in itself mark the first time a CubeSat planetary entry capsule is flight tested, not only at Goddard, but anywhere else in the world," says Esper, who believes the concept might appeal to universities and cash-strapped researchers. "That in turn enables new opportunities in planetary exploration not available to date, and represents a game-changing opportunity for Goddard."