Hunting for life's cosmic origin

Two pioneering spacecraft are about to enter orbit around two different asteroids. What they find could shed light on how life on Earth began.

25th July 2018
Hunting for life's cosmic origin © Magic Torch

OSIRIS-REx. Hayabusa2. Make a note of these two names: you’re going to be hearing a lot about them over the coming months and years. These spacecraft – one operated by NASA and the other by the Japan Aerospace Exploration Agency, JAXA – will this summer each enter into orbit around a target asteroid. They promise to teach us a great deal about the origins of the Solar System, how we might deflect an asteroid on a collision course with the Earth, and even the molecular origins of earthly life.

Both NASA’s OSIRIS-REx and JAXA’s Hayabusa2 are sample-return missions, which means that not only will they touch gently onto their asteroid’s surface to collect a scoop of its ancient material, but they will then return it safely back to eagerly waiting scientists on Earth. This sort of return trip mission within deep space is fabulously complex, and both probes are marvels of engineering. The Japanese probe is a follow-up to their earlier asteroid mission, Hayabusa, which returned a small sample from the asteroid Itokawa in 2010. Despite suffering numerous glitches, Hayabusa racked up a string of accomplishments, including being the first spacecraft designed to land and take off from an asteroid and the first to return an asteroid sample to Earth. Hayabusa2 uses the same basic spacecraft structure as its predecessor, but incorporates more backup systems to improve reliability, along with some technological advances. As well as upgrades to the communication antenna and guidance systems, Hayabusa2’s ion engines are 25 per cent more powerful than its predecessor’s, and the probe will be able to autonomously control its own final descent to the remote asteroid’s surface. Hayabusa2 is also like a mothership in its own right – it will deploy a small lander and three rovers onto the asteroid’s surface for a closer look, which can hop around the landscape to different locations.

Meanwhile, NASA’s OSIRIS-Rex (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) will be the first ever US asteroid sample-return mission. This spacecraft is about twice the size of Hayabusa2, and rather than using ion engines will fire standard rocket thrusters to accelerate on its trajectory to its target asteroid. When they arrive this summer, both missions will survey their target asteroids for about a year and a half, mapping the surfaces and remotely detecting minerals using spectroscopy. Scientists will then use these results to help them decide the best spot on their asteroids for Hayabusa2 and OSIRIS-REx to descend to collect their samples.

Time capsules

Asteroids are important because they represent primordial material left over from the making of the planets. They are like time capsules from before the creation of the Earth, preserving matter since the beginning of the Solar System. By studying them up-close, scientists hope to be able to answer some pretty fundamental questions about the formation and development of the Solar System. Specifically, it will help us to understand how planets like the Earth were born, by allowing us to observe the material from which rocky planets form...

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