Piggybacking on interplanetary missions

ESA’s mission Rosetta, which was launched in 2004 and arrived at Comet 67P/Churyumov-Gerasimenko on August 6, 2014, stirred the world. It is the first mission in history to rendezvous with a comet, escort it as it orbits the Sun and deploy a lander to its surface. According to Bert Vermeersen, the future holds many more missions in which a mothership deploys mini probes, be it miniature satellites or landers. Or so he told his audience during his inaugural speech on June 10, 2015. Vermeersen was recently appointed professor of planetary exploration at the Faculty of Aerospace Engineering and the Faculty of Civil Engineering & Geosciences.

“This trend will bring space exploration to regions beyond the moon within reach for universities”, said Vermeersen. “Universities’ research budgets are dwarfed by those of space agencies such a ESA or NASA, yet their role in space exploration can increase if the equipment they work on piggybacks on large interplanetary missions.”

Vermeersen has hopes that his group might get involved in the Asteroid Impact & Deflection Assessment (AIDA) mission, led by ESA. “This interplanetary mission is not 100% scientific, like almost all other interplanetary missions, but plays a role in planetary protection against possible future earth-impacting near-earth objects. The goal of this safety and security mission is to test whether a spacecraft could successfully deflect an asteroid on a collision course with Earth by crashing into it.”

The first part of AIDA consists of only studying an asteroid, or actually two asteroids; the target 65803 Didymos is a binary asteroid system in which one asteroid is orbited by a smaller one. Later NASA will launch a spacecraft that will push the small asteroid out of its orbit.

ESA plans to launch its spacecraft in 2020. It has room for six cubesat units, most likely leading to two small 3-unit probes, that will be deployed once the craft reaches its destination. ESA has a tender to which universities, research institutes and companies can apply.

“The instrument we would like to send along with this mission is a spectropolarimeter”, said Vermeersen. “It measures the reflection of the sunlight on the surface of the asteroid and from that it deduces what material it is made out of and its roughness. We develop it together with colleagues from Leiden University and several space companies”

Competition for this tender is tough. But whatever the outcome, Vermeersen expects many more such opportunities to arise. “Space agencies have acquired a taste for missions with miniprobes, as they allow them to take extra risks. If a probe fails in its tasks or gets destroyed, the mission as a whole isn’t compromised. And thanks to the miniaturization of probes and equipment and ever-increasing energy efficiency, it becomes easier to bring them along. The university is good in these fields. The new TU Delft Space Institute should continue the effort in these areas.”

Robotics also forms another aspect in future interplanetary space missions. And also here TU Delft can play an important role according to Vermeersen. “When Curiosity, one of the Mars Exploration Rovers of NASA, arrived at Mount Sharp last year, sharp rocks punctured its tires. It would have been practical if a little robotic airborne drone had flown ahead to inspect the environment, like a reconnaissance chaperone. A drone like the Delfly, MarsFly, might be suitable for this.”

The Delfly, a micro air vehicle reminiscent of a dragonfly, is tested at the Delft Cyber Zoo, a research and test laboratory in the aircraft hangar at the Faculty of Aerospace Engineering. Many other robots are tested here, such as the Zebro, a six-legged search and rescue robot that can navigate treacherous terrain. Will one day a whole zoo of robots be deployed in space? Vermeersen thinks this might be quite realistic. “Independently operating robots on various kinds of vehicles is certainly one of the future challenging elements in interplanetary exploration.”