A small, shoebox-sized spacecraft delivered to ESA’s Hera mission this week promises to make a giant...
Once deployed from the Hera spacecraft at the Didymos binary asteroid system, the Juventas CubeSat perform the first radar probe within an asteroid, peering deep into the heart of the Great-Pyramid-sized Dimorphos moonlet.
"Today's asteroids are collisional fragments of the original building blocks of our entire Solar System, so being able to see how the interior of an asteroid is structured will give us valuable insights into the evolution of the Solar System, as well as planetary defence," explains Michael Kueppers, ESA's Hera project scientist.
Jan Persson leads the Juventas project for GomSpace: "This is a very different mission compared to the usual CubeSats that we manufacture and fly. Going beyond Earth orbit and out into deep space is a rare opportunity, requiring extremely precise attention to detail. Juventas also needs a sufficiently agile navigation system to fly itself around an asteroid."
ESA's Hera asteroid mission is Europe's contribution to an international planetary defence experiment.
Following the DART mission's impact with the Dimorphos asteroid, a moon of the larger asteroid Didymos, in 2022 - modifying its orbit around Didymos and sending a plume of debris thousands of kilometres out into space - Hera will return to Dimorphos to perform a close-up survey of the crater left by DART. The mission will also measure Dimorphos' mass and make-up, along with that of Didymos.
Hera is due for launch in October 2024, and aboard it will be two CubeSats for close-up observations of the asteroid pair: Juventas will be joined by the Milani hyperspectral mission.
"The Juventas Radar - or JuRa - instrument is unique, and will give the science community a rare insight into the making of an asteroid," explains Jan Persson.
In order to perform its radar survey of the smaller asteroid, Juventas will go into a unique 'Self-stabilised Terminator Orbit' around Didymos.
Didymos's gravity is so low that Juventas will be orbiting at a rate of just centimetres per second, and JuRa will take advantage of that low speed to send the same coded signal down to the asteroid multiple times, boosting the instrument's overall signal to noise ratio.
Once Juventas completes its radar survey, it will switch into orbit around Dimorphos to begin the next phase of its mission: landing on the smaller asteroid.