The space agency is making the finishing touches on its ultimate goal, which will see the OSIRIS-REx spacecraft touchdown on asteroid Bennu, where it will grab some samples and return them to Earth. On August 11, OSIRIS-Rex will perform its ‘Matchpoint’ rehearsal, where it will rehearse several manoeuvres before the ultimate grab in October.
The grab needs to be perfect, as not only is the asteroid travelling at 28 kilometres per second but it is also slowly rotating as zooms through the solar system.
For this reason, NASA needs to time the OSIRIS-REx thrusters perfectly to ensure it can land safely and take off again.
During the coming run, OSIRIS-Rex will reach an altitude of approximately 131 ft (40 m) before backing away from the asteroid.
NASA explained: “During the descent, the spacecraft fires its thrusters three separate times to make its way down to the asteroid’s surface.
“The spacecraft will travel at an average speed of around 0.2 mph (0.3 kph) during the approximately four-hour excursion.
“Matchpoint rehearsal begins with OSIRIS-REx firing its thrusters to leave its 0.5-mile (870-m) safe-home orbit.
“The spacecraft then extends its robotic sampling arm – the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – from its folded, parked position out to the sample collection configuration.
“Following Matchpoint rehearsal, the OSIRIS-REx team will verify the flight system’s performance during the descent, including that the Matchpoint burn accurately adjusted the spacecraft’s descent trajectory for its touchdown on Bennu.
By collecting samples, NASA hopes to unlock the secrets of the solar system, as Bennu is a remnant of our galactic neighbourhood’s formation some 4.6 billion years ago.
Bashar Rizk, instrument scientist for OSIRIS-REx said: “The story of this asteroid is the story of the solar system.
“When we understand Bennu, we will understand something fundamental about our solar system.”