OSIRIS-REx Sharpens Re-entry Path with Critical TCM-10 Burn

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Timeline of Events for OSIRIS-REx Sample Return maneuvers and release. Image Credit: Lockheed-Martin/GSFC/KinetX

Tomorrow, the OSIRIS-REx mission will perform a trajectory correction maneuver (TCM-10) in preparation for its asteroid sample return later this fall. The primary goal of TCM-10 is to reduce the spacecraft’s closest approach altitude above the Earth’s surface from approximately 2300 km (1430 miles) to approximately 210 km (130 miles). This is made possible by a reduction in the predicted uncertainties of the spacecraft trajectory as the spacecraft gets closer to Earth. The spacecraft will execute TCM-10 by firing 4 of its attitude control thrusters for 64 seconds in order to adjust the spacecraft's velocity by 57 cm/s (1.28 mph). TCM-10 is necessary because it helps reduce the fuel cost and improves the delivery performance of the final Earth targeting maneuvers, which are planned for the weeks just before SRC Release. TCM-10 will be executed on July 26, which marks 60 days until the release of the Sample Return Capsule, which is set to land in the Utah desert on September 24, 2023.

A full timeline of navigation-related events, including nominal and contingency maneuver opportunities before and after sample return (SRC release) are provided below.

OSIRIS-REx Sample Return Timeline of Navigation-Related Events

Date	Event
17-Jul-23	TCM-10/TCM-10a Final Design Data Cutoff
25-Jul-23	OD361 Delivery
26-Jul-23	TCM-10 Execution
28-Aug-23	TCM-11 Preliminary Design Data Cutoff
8-Sep-23	TCM-11 Final Design Data Cutoff
10-Sep-23	TCM-11 Execution
11-Sep-23	TCM-12 Preliminary Design Data Cutoff
12-Sep-23	Begin Daily Orbit Determination Solutions and Deliveries
15-Sep-23	TCM-12 Final Design Data Cutoff
17-Sep-23	TCM-12 Execution
21-Sep-23	Contingency TCM-13 Final Design Data Cutoff
23-Sep-23	Spacecraft moves to SRC Release attitude
23-Sep-23	Contingency TCM-13 Execution
23-Sep-23	Conjunction Avoidance Maneuver Go/No-Go Decision
23-Sep-23	Contingency Conjunction Avoidance Maneuver Execution
24-Sep-23	SRC Release and Earth Entry
24-Sep-23	Earth Divert Maneuver Execution
9-Oct-23	TCM-14 Preliminary Design Data Cutoff
16-Oct-23	TCM-14 Final Design Data Cutoff
23-Oct-23	TCM-14 Execution