NASA is preparing to pull off a daring heist: Next month the robotic spacecraft OSIRIS-REx will touch down on the surface of asteroid Bennu and collect a sample, aiming to precisely touch this tiny asteroid just 260 meters wide and which is currently around 207 million miles away from Earth.
The aim of the mission is to collect at least 60 grams of asteroid rock in an event called Touch-And-Go (TAG) and return it to Earth for study, which would be the first time NASA has collected an asteroid sample. Analyzing the composition of primitive asteroids like Bennu could give clues to how the solar system developed and even about the origin of life on Earth.
But it’s no easy task to scoop up a sample from an object that’s so far away. Due to the distance from Earth, it’s not possible to control the OSIRIS-REx craft in real-time. So on the day of the event, October 20, it will have to act autonomously to maneuver and approach the asteroid using a pre-determined sequence.
“Because the spacecraft and Bennu are approximately 207 million miles (334 million km) from Earth during TAG, it will take about 18.5 minutes for signals to travel between them,” NASA explains in a blog post. “This time lag prevents the live commanding of flight activities from the ground during the TAG event, so the spacecraft is designed to perform the entire sample collection sequence autonomously. Prior to the event’s start, the OSIRIS-REx team will uplink all of the commands to the spacecraft and then send a ‘GO’ command to begin.”
The process of collecting the sample will take 4.5 hours, and NASA has been going through practice runs ahead of the real touch down next month. The agency says it’s ready to go ahead with the touchdown despite the challenges of coronavirus which have forced the mission team to work remotely.
On the day of the event, a few key personnel will monitor from the main Mission Support Area, while other team members will be at other locations to check whether the touchdown has been successful and to confirm whether a sufficiently large sample has been collected.