Image: July 23, 1999, Chandra X-ray Observatory awaits deployment

This 70mm frame shows the 50,162-pound Chandra X-ray Observatory before it was tilted upward for its release from the Space Shuttle Columbia's payload bay on July 23, 1999, just a few hours following the shuttle's arrival in Earth orbit. Chandra was spring-ejected from a cradle in the payload bay at 6:47 a.m. Central time. Commander Eileen Collins, the first female Shuttle Commander, maneuvered Columbia to a safe distance away from the telescope as an internal timer counted down to the first of a two-phase ignition of the solid-fuel Inertial Upper Stage (IUS). The IUS lit up as scheduled at 7:47 a.m., and a few minutes later, shut down as planned, sending Chandra on a highly elliptical orbit which was refined over the next few weeks by a series of firings of telescope thrusters, designed to place Chandra in an orbit about 6900 x 87,000 statute miles above the Earth.

In August 2015, Chandra will pass the 16th anniversary of another milestone in the mission – the release of the "First Light" images from the telescope. As of July 1st, 2015, Chandra has traveled over 17 billion miles while completing about 2,200 orbits of the Earth. Chandra has made over 14,000 observations over the last 16 years. The targets include objects as close as the Earth and as distant as black holes near the edge of the observable universe.