Vela 3A (also known Vela 5, Vela Hotel 5 and OPS 6577) 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 3B and ERS 17 satellites. The secondary task of the ship was space research (X-rays, gamma rays, neutrons, magnetic field and charged particles). Sister Vela 3B was in a similar orbit, but 180 degrees from it, i.e. on the opposite side of the globe. The ship remains in orbit around Earth.