The odometer on NASA's Hubble Space Telescope is about to turn over 100,000. That's not 100,000 miles but the number of orbits it has made around Earth since it was launched aboard the space shuttle Discovery on April 24, 1990.

To remain in orbit the spacecraft zooms along at nearly five miles per second. So Hubble's actual odometer mileage is approximately 2.72 billion miles, the equivalent of 5,700 round trips to the Moon. It's also the number of miles Americans will drive today in less than 3 hours.

That's not bad considering Hubble doesn't use fuel of any kind, only Earth's gravity to maintain it in a circular orbit.

Although Hubble doesn't require fuel, it is similar to cars and other vehicles in that it does have wear and tear, and needs servicing and upgrading from time to time. It's dinged by micrometeorite impacts, and sunlight and temperature extremes degrade its silvery thermal insulating material.

The telescope will get another tune-up in October when astronauts aboard the space shuttle Atlantis make one final mechanic's check to replace worn components and install spanking new instruments to extend Hubble's vision.

Hubble's odometer turns over at 7:42 a.m. EDT on August 11. At that time Hubble will be moving northward as it crosses the intersection point where its orbit passes directly over Earth's equator.