The Apollo spacecraft contained a separate, inertial guidance and navigation system that enabled its crew to navigate from Earth orbit to the Moon and back. It consisted of three principal parts. One was an inertial measurement unit (IMU), which contained gryoscopes and accelerometers that established a base position and attitude for the craft. The second was an optical unit, including a sextant, which allowed the astronauts to update the IMU's settings based on sightings of stars and planets. The third was a digital computer.
This artifact is part of the Command Module's Sextant. It is an unflown back-up specimen.
NASA transferred this object to the Museum in 2001.