Rehearsal time for NASA's asteroid selection spacecraft


Rehearsal time for NASA's asteroid selection spacecraft

This concept of the artist shows the trajectory and configuration of NASA’s OSIRIS-REx spacecraft during the rehearsal of Checkpoint, which will be the first mission in practice with the initial steps to collect a sample from the asteroid Benno. Credit: NASA / Goddard / Arizona University

In August, a robotic spacecraft will make NASA's first attempt to climb the asteroid's surface, collect a sample, and eventually return it safely to Earth. To address this challenging challenge, the OSIRIS-REx mission team has developed new techniques for working in the asteroid Bennus micro-environment, but they still need the experience of flying a spacecraft near the asteroid to test them. This summer, before discussing the Nightingale test site, OSIRIS-REx is rehearsing for the first time before the event.


On April 14, the mission will carry out the first exercise, officially known as the "checkpoint" rehearsal, which will also place the spacecraft closest to what has ever been in Benno. This rehearsal is a chance for OSIRIS-REx Group and the spacecraft to test the first steps of the robot sample collection event.

In full touch sequence, the spacecraft uses three separate firearms to pass through the surface of the asteroid. After the orbit leaves, the spacecraft completes a maneuver at Bennu at a height of 410 feet (125 m), which regulates the spacecraft's position and accelerates to the third burn point. This third maneuver, called the "match point", takes place about 164 feet (50 m) from the surface of the asteroid and places the spacecraft on a trajectory that coincides with the rotation of Bennus as it further aspires to the point of target contact.

The rehearsal of the launch site allows the team to navigate the spacecraft through both orbital departure and maneuvering maneuvers, and ensures that the spacecraft’s visualization, navigation, and outbound systems work as expected during the first part of the descending sequence. The rehearsal of the checkpoint also allows the team to confirm that the OSIRIS-REx Natural Tracking System (NFT) guidance system will accurately reset the spacecraft's position and speed relative to Bennu as it passes through the surface.

The rehearsal of the launch site, a four-hour event, begins with the spacecraft leaving its safe orbit, 0.6 miles from the asteroid. The spacecraft then expands its robotic selection weapons – the Touch-And-Go Sample Purchase Mechanism (TAGSAM) – from its folded, parked position to the sample collection configuration. Immediately after that, the spacecraft joins or rotates to begin collecting navigation images for the NFT manual. The NFT is giving the spacecraft the ability to autonomously navigate the surface of Bennu, comparing navigation images taken in real time taken during the origin of the comparative spacecraft catalog. As the spacecraft lands on the surface, the NFT system will update the pre-determined point of the spacecraft, depending on the positions of OSIRIS-REx, in relation to the sights of Benu.

410 – Fut (125 – meters) Before reaching the checkpoint height, the spacecraft's solar masses move into the "Y-wing" configuration, which safely puts them on the surface of the asteroid. The configuration center of the spacecraft is also located directly above the TAGSAM collector, which is the only part of the spacecraft that will contact the Bennus surface when collecting specimens.

In the midst of this activity, the spacecraft continues to take pictures of Bennu’s surface for the NFT navigation system. The spacecraft will then burn at the checkpoint and head for the surface of Benoit for another nine minutes, placing the spacecraft closest to the asteroid – 243 feet (75 m).

Upon reaching this target point, the spacecraft will perform a rear fire, then return the solar arrays to their original state and repair the TAGSAM arm again in the stationary state. Once the mission team has determined that the spacecraft has successfully completed the entire rehearsal sequence, they will instruct the spacecraft to return to its safe home orbit around Benno.

After rehearsing the checkpoint, the team will check the operation of the flight system at the time of origin and that the burn at the checkpoint has accurately regulated the descending trajectory for further match point burns.

The mission team has been working as far as possible in the last month of preparation for rehearsals at the checkpoint as part of the COVID-19 response. On the day of rehearsal, a limited number of staff will carry the spacecraft from the Lockheed Martin Space facility, take appropriate action, and the rest of the team will perform their roles remotely.

The mission is scheduled to hold a second rehearsal on June 23, with the spacecraft Matchpoint burns to a height of 82 meters (25 m). An attempt to collect the first sample of OSIRIS-REx is scheduled for August 25.


OSIRIS-REx features Nightingale on sample sites


ᲛMore information:
For more information about NASA's OSIRIS-REx mission, visit www.nasa.gov/osiris-rex

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NASA's Goddard Space Flight Center

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Rehearsal time for NASA's asteroid selection spacecraft (April 10, 2020)
Read April 13, 2020
https://phys.org/news/2020-04-rehearsal-nasa-asteroid-sampling-spacecraft.html

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