The board also confirmed the right engine experienced a surge during a flight on January 13, and subsequent repairs included the replacement of a temperatureprobe.
Based on the Phoenix lander, the craft is tasked with giving us a peek beneath the planet's surface, armed with tools that include a geodetic instrument from the Jet Propulsion Laboratory, which will be used to calculate Mars' rotation axis, a seismic wave sensor and a subsurface heat probe, to measure the planet's internal temperature.
To measure that, the four gyroscopes in Gravity Probe B are made of fused quartz spheres, which will not expand or contract as the temperature changes.