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Link here. The story is focused on the decision by NASA to hold off launching a replacement for MRO and instead keep it operating for another decade. In telling this story, however, the article also provides us a detail look at the spacecraft’s present condition.
[A]ging batteries and gyroscopes, used to store electricity and aid navigation, will have to be carefully watched in the coming years to keep the mission going. “We found that they weren’t charging at full capacity,” Tamppari said of the batteries. MRO charges its batteries through its solar arrays while in sunlight. During night passes over Mars, the orbiter draws electricity from its batteries for about 40 minutes during each two-hour lap around the planet. The spacecraft now charges its batteries higher than before, NASA said, and engineers sent up commands for MRO to reduce the draw on the batteries while in shadow.
MRO’s two inertial measurement units are also showing signs of their age. Each redundant unit contains three gyroscopes and three accelerometers, feeding data about the spacecraft’s orientation to on-board computers. One measurement unit likely in the final months of its useful lifetime, Tamppari said, and the other is showing signs of degradation.
Ground controllers found a work-around by implementing an “all-stellar” navigation mode on MRO in March. The new technique allows the orbiter to sense the positions of the stars to determine which way it is pointing. “In all-stellar mode, we can do normal science and normal relay,” said Dan Johnston, MRO project manager at JPL, in a statement released in February. “The inertial measurement unit powers back on only when it’s needed, such as during safe mode, orbital trim maneuvers, or communications coverage during critical events around a Mars landing.”
There’s more at the link. Since MRO is also used as the main communications relay satellite between the Martian ground-based probes and the Earth, the story also outlines the communications capabilities of all spacecraft presently orbiting Mars. All told, it seems that if MRO fails the research on the surface will be significantly impacted, even if the rovers and landers are all still working.