The Space Shuttle Columbia delivered Chandra to a low Earth orbit. Then, the Inertial Upper Stage rocket boosted Chandra up to a higher altitude where a built-in propulsion system took Chandra to its final orbit.
This elliptical orbit takes the spacecraft to an altitude of 133,000 km (82,646 mi) - more than a third of the distance to the moon - before returning to its closest approach to the Earth of 16,000 kilometers (9,942 mi). It takes approximately 64 hours and 18 minutes to complete an orbit.
The Chandra spacecraft spends approximately 85% of its orbit above the Van Allen belts, charged particles that surround the Earth.
This makes uninterrupted observations of as long as 55 hours possible, making the overall percentage of useful observing time much greater than the low Earth orbit of a few hundred kilometers used by most satellites.