Yesterday, OSIRIS-REx The spacecraft made the last practice run of the sampling sequence, reaching a height of approximately 40 meters above the Nightingale sampling site before performing a rear-end ignition. Nightingale, OSIRIS-REx’s main sample collection site, is located in the crater in the northern hemisphere of Bennu.
The roughly four-hour “Matchpoint” exercise took the spacecraft through the first three of the sampling sequence’s four maneuvers: burning the trajectory, burning the ‘Check Point’, and burning the Matchpoint. The checkpoint is the point where the spacecraft automatically checks its position and velocity before adjusting its trajectory down to the third maneuvering direction of the event. The match point is the moment when the spaceship matches Bennu’s rotation to fly parallel to the asteroid surface, just above the sample location, before hitting the targeted point.
Four hours after leaving a safe home orbit of 0.6 miles (1 km) long, OSIRIS-REx performed a Checkpoint operation at an altitude of approximately 125 feet (125 meters) above the surface of Bennu. From there, the spacecraft continued to descend for another 8 minutes to perform Matchpoint burning. After descending into this new orbit for another three minutes, the spacecraft reached an altitude of approximately 131 ft (40 m) – the nearest altitude the spacecraft ever reached for Bennu – and then performed a backfire to complete rehearsal.
These images were taken over a period of 13.5 minutes. The photographic sequence started at about 420 feet (128 meters) above the surface – before the spacecraft did the “Check Point” operation – and ran through the “Match Point” maneuver, with the final image. the same shot was about 144 feet (44 meters) above the surface of Bennu. The spacecraft’s sampling arm – known as the Inductive Sample Collection Mechanism (TAGSAM) – is visible in the lower part of the frame. Credit: NASA/ Goddard / University of Arizona
During maneuvers, the spacecraft successfully deployed its sampling arm, Induction and Start Sample Collection Mechanism (TAGSAM), from its folding and parked position to the sample collection configuration. In addition, a number of spacecraft instruments collected scientific and navigational images, and made spectral observations of the sampling site, as would occur during a sample collection event. These scientific images and data were linked down to Earth after the event ended.
Because spacecraft and Bennu are currently about 179 million miles (288 million km) away from Earth, it takes about 16 minutes for the spacecraft to receive the radio signals used to command you. This time delay hindered the direct command of ground-based flight operations during the maneuvers. As a result, the spacecraft performed the entire series of maneuvers autonomously. Before the drill began, the OSIRIS-REx team linked all of the event commands to the spacecraft and then provided a “Go” command to start the event. The actual sample collection event in October will proceed in a similar manner.
This second rehearsal provided the mission team to practice navigating the spacecraft through the first three maneuvers of the sampling event and had the opportunity to verify that the imaging, navigation, and The spacecraft’s range works as expected in the first part of the down chain.
The Matchpoint drill also confirmed that OSIRIS-REx’s Natural Feature Tracking (NFT) system accurately estimated the spacecraft’s trajectory after the Matchpoint fire, which was the last maneuver before the start of the match. Collect samples in contact with Bennu’s surface. This exercise was also the first time the spacecraft hazard map was used. Hazard maps delineate areas of potential damage to spacecraft. If the spacecraft detects that it is hitting a dangerous area, it will reverse automatically after reaching an altitude of 16 ft (5 m). Although OSIRIS-REx did not fly that low during maneuvers, it used hazard maps to gauge whether its predicted downward trajectory avoids hazards on the surface and receives see that the spaceship’s path during maneuvers will allow the Nightingale to touch down on the safety model.
During the final minutes of the spacecraft landing, OSIRIS-REx also collected new, high-resolution navigation images for the NFT navigation system. The detailed images of Bennu’s landmarks will be used for the sampling event and will allow the spacecraft to precisely target a very small area.
“Many important systems were implemented in this exercise – from communication systems, spacecraft propulsion systems and most importantly, the ship nature Tracking guidance system and maps. is dangerous, ”said OSIRIS-REx lead investigator, Dante Lauretta of the University of Arizona, Tucson. “Now that we have completed this milestone, we are confident in finalizing the TAG event procedures. This exercise confirmed that the team and all of the spacecraft’s systems are ready to collect a sample by October.
The mission team has spent the past months preparing for Matchpoint drills while maximizing remote work as part of COVID-19 react. On the day of the drill, a limited number of personnel overseeing the spacecraft’s telemetry from the Lockheed Martin Space facility, NASA’s Goddard Space Flight Center, and the University of Arizona, took defensive measures. take proper safety precautions, while the rest of the team perform their roles from afar.
The spacecraft will move to the asteroid’s surface during its first sampling test, scheduled for October 20. During the event, OSIRIS-REx’s sampling mechanism will touch Bennu’s surface for a few seconds, shoots out a burst of pressurized nitrogen to jam the surface and collect a sample before the spacecraft pulls back. The spacecraft is scheduled to return the sample to Earth on September 24, 2023.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, system engineering as well as safety and mission assurance to OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the lead investigator, and the University of Arizona also leads the mission’s science and science observation planning and data processing team. Lockheed Martin Space in Denver built the spacecraft and provided flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontier Program, administered by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.