On Nov. 28, NASA’s LunaH-Map spacecraft acquired its first star tracker image, showing the constellation Auriga and its two brightest stars, Menkalinan and Mahasim. The LunaH-Map navigation team used these images to test a new type of autonomous optical navigation software that can be run on the spacecraft’s flight computer. On Dec. 2, LunaH-Map also successfully acquired observations of Mars and Uranus and processed them onboard using the autonomous optical navigation software routines. The test was successful and demonstrated that the autonavigation software could autonomously correct raw images onboard, estimate the inertial camera orientation using visible stars, compute the astrometric centers of planetary targets in the field, and compute offsets relative to the spacecraft state. Each of these measurements are critical to performing autonomous navigation with onboard images, without the intervention from operators on Earth. Optical navigation algorithms like the one demonstrated on LunaH-Map will be important for future small spacecraft to perform operations in deep space, given their minimal communications resources.
The mission team also made several attempts to image the Earth and Moon; however, these images resulted in saturation of the star tracker. In the coming weeks, additional imaging opportunities of the Earth and Moon will be evaluated to help further demonstrate these novel autonavigation capabilities.
While a recent telemetry downlink showed an unexpected spacecraft reset, a Deep Space Network (DSN) pass has since indicated that, with the exception of the likely stuck propulsion system valve, the spacecraft is healthy with all subsystems nominal and operating as expected.
NASA’s Jet Propulsion Laboratory and the DSN teams are scheduling a set of tracks for the week of Dec. 5 the team will use to demonstrate a new type of radio ranging technique called Pseudo Noise Differential One Way Ranging (PN DOR). This is a first-time demonstration of PN DOR and will enable better ranging accuracy on future deep space CubeSats as well as larger missions.
The LunaH-Map science team began analysis of the lunar neutron data acquired during the spacecraft’s lunar flyby, including assessing the geometric effects related to the detector, spacecraft and Moon. From the flyby altitudes, the Moon’s epithermal neutron albedo measured by LunaH-Map can be used to derive a bulk hydration of the Moon, which can be compared with previous lunar orbital neutron measurements made by NASA’s Lunar Prospector and Lunar Reconnaissance Orbiter spacecraft. This measurement demonstrated that the instrument can achieve LunaH-Map’s science mission to map ice at the lunar South Pole.
After several whirlwind weeks, the LunaH-Map operations team took the first much-needed break since launch. They are working on a few minor ground system issues and finalizing the procedures and schedules related to the upcoming PN DOR radio ranging test. The team will soon enter an operational cadence with long (multi-day) heating of the propulsion system valve, followed by communications passes to focus on multiple ignition attempts that will, if successful, enable the completion of the LunaH-Map science mission later next year.