Vela 3B (also known Vela 6, Vela Hotel 6 and OPS 6564) was a U.S. reconnaissance satellite to detect explosions and nuclear tests on land and in space; the first of the third pair of Vela series satellites; taken together with Vela 3A and satellites. The secondary task of the ship was space research (X-rays, gamma rays, neutrons, magnetic field and charged particles). The ship remains in orbit around Earth.