May-June 2002: A photo taken at Lockheed Martin in Sunnyvale, California, reveals the major components of the SIRTF observatory, now in post-integration testing. The entire observatory is four meters in height and will have a launch mass of 950 kg. The 85-cm diameter telescope, composed of lightweight beryllium, is on the right. The cryostat and cold science instruments are hidden in the lower portion of the cylindrical telescope assembly. The spacecraft is located below the cryogenic telescope assembly, and contains the Observatory's electronics and computers, in addition to power-generation and communications equipment. The solar panels, mounted on the protective shields to the left, convert the Sun's light into electricity. The outer shields are always kept between the Sun and the telescope assembly in order to keep the telescope as cold as possible.