Jul 08, 2019
This week, OSIRIS-REx successfully executed its first week of global mapping from Orbital B’s low altitude orbit. On July 1, the team observed Bennu with the spacecraft’s onboard science instruments (except for OVIRS). During the global mapping phase of Orbital B, OLA will collect data in support of 5-cm Digital Terrain Models (DTMs) for site-specific mapping. PolyCam will obtain intermediate-resolution imagery to help determine sampleability of Bennu’s topography. OTES will gather data to create local thermal inertia maps, and REXIS will analyze X-ray fluorescence. NavCam, a navigation instrument, will also contribute to the scientific investigation by continuing intensive dedicated particle imaging. July 1 also marked the first time that REXIS observed asteroid Bennu. The current global mapping effort supports the down-select process to identify the four sample sites that will be further studied as the mission moves into its Reconnaissance phase.
On July 3, OLA returned to operations after recovering from an instrument-level safe mode event. The spacecraft’s fault protection systems had safed the instrument on July 2 as a precaution when OLA did not respond to a routine aliveness check after completing 17 of 19 scans of Bennu’s surface. Investigation of telemetry subsequent to the event revealed no anomalous instrument behavior other than a few status bits that had flipped, potentially indicative of a radiation induced event. OLA was power-cycled to clear the issue, and instrument recovery and return-to-operations proved successful.