Hayabusa Shoots An Asteroid For Science by Scott Manley

Daniel de Zeeuw
daniel@b612foundation.org

March 8, 2019

The Hayabusa2 spacecraft has spent the last few months surveying the asteroid Ryugu with its array of sensors and micro rovers with an eye to finding suitable sites to sample. Launched in 2016 the Japanese mission aims to return samples of this asteroid from above and below the surface. It’s a fascinating mission, consisting of a core spacecraft with optical, infrared and LIDAR sensors and supported by a small armada or specialized micro-spacecraft, some of which have been deployed to the surface and returned detailed images showing the regolith resembled packed gravel.

Having identified a suitable location to collect a sample a plan was made and the spacecraft spent hours carefully approaching the surface at speeds slower than walking pace, bringing its collection device close to the regolith. To actually get the material off the surface the spacecraft hit it with a small kinetic impactor device, or in simple terms a bullet was shot into the surface throwing up a cloud of debris.

 

This is the first of two samples, for the second sample Hayabusa will deploy a specialized device called the Small Carry On Impactor. This uses a shaped explosive charge to drive a 2.5 kilogram copper impactor into the surface with enough energy to expose pristine asteroid material, insulated from the effects of space weathering. This impactor will be operated remotely, with Hayabusa retreating behind Ryugu and using it as a shield, but it will also leave behind a small camera to document this energetic event. After the debris clears, Hayabusa will return, survey the changes to the surface and when ready, it will descend again, looking to collect a sample from inside the newly formed crater.

The samples are ultimately going to be returned to the Earth in 2020 for analysis at JAXA’s Extraterrestrial Sample Curation Center, providing possibly the oldest pristine sample of the material which formed the planets of the solar system. One of the things the scientists hope to find is organic molecules which formed in the solar nebula billions of years ago.

Even right now the process of collecting the samples is providing fascinating data on the structural properties of asteroid surfaces, and we expect the process of hitting an asteroid hard with a projectile to have a direct impact on the analysis of asteroid deflection models.

 

About Scott Manley:

Scientist, astronogamer, astrophysicist, programmer, and YouTube star, Scott is known for his space-themed YouTube channel where he brings science into video games and teaches kids of all ages the math behind rocket science. Originally from Scotland, Scott spent a decade in academia studying astrophysics and computational physics at the University of Glasgow and Armagh Observatory where he focused on small bodies in the solar system and specifically the probabilities of collision. He left research in 1999 to move to California and work in the technology industry. When the video game Kerbal Space Program appeared, he became a public science figure through his YouTube videos explaining the game and the science involved. His videos have generated almost 200 million video views and 600,000 subscribers.

Daniel de Zeeuw
daniel@b612foundation.org