The Chandra Launch Mission: STS-93

Courtesy of NASA's STS-93 image archives.

The notable launch of the Chandra x-ray observatory took place on Tuesday, July 22, 1999. Chandra was launched by the Columbia space ship, which, as we all know, has since been destroyed. The Chandra mission was Columbia’s 26^th mission. It was the 20^th nighttime launch by NASA, and its 95^th overall.

Columbia was the oldest shuttle in NASA’s fleet, and was named after a Boston ship captained by an American man named Robert Gray. Columbia was also considered to be the “feminine” personification of the United States, and also had references to the explorer Christopher Columbus in its name. Historically, Columbia is important: it was the first shuttle to orbit the Earth (in 1981). Columbia is commonly referred to as OV-102, for Orbiter Vehicle-102. Empty weight was 158,289 lbs at rollout and 178,000 lbs with main engines installed. [1] The Columbia was awarded a contract in 1972, and construction began on it in 1975. It carried out missions constantly until it broke up upon reentry in February 2003 on STS- 107.

The crew of STS-93 included Commander Eileen Collins, Pilot Jeff Ashby and Mission Specialists Cady Coleman, Steve Hawley and Michel Tognini. The Chandra launch mission was historically significant because Eileen Collins was NASA’s first female space mission commander. [2]

The launch was from NASA’s John F. Kennedy flight center in Florida. It was an STS launch; STS stands for Space Transportation System. The STS mechanism consists of the Space Shuttle Orbiter, which in this launch was the Columbia space shuttle itself, a disposable external tank containing liquid hydrogen and liquid oxygen, and two redesigned solid rocket motors in recoverable solid rocket boosters. The Chandra was attached to a rocket booster and placed in Columbia’s payload bay for the launch. Once the shuttle reached the proper height, Chandra was released, with two IUS solid motors holding the observatory in an elliptical orbit around the Earth. Chandra’s propulsion system powered the observatory to raise itself to its final height of 10000 x 140000 km above the Earth. [3]

The mission had been postponed twice, but it finally was scheduled for July 22 at 12:30 in the morning. Upon launch, the crew encountered some problems with the voltage, causing the controllers on two of three engines to shut down. Obviously, they had to make some adjustments, though the engines were still working adequately. The crew began to try to figure out what caused the voltage drop, and nine minutes into flight, the crew was in its orbit. [4]

The primary function of the STS-93 mission was to launch the Chandra X-Ray Observatory, which would hopefully lend astronomers and scientists new sight into astronomy by observing x-ray energy, which had in the past been a source of confusion for astronomers, because they didn’t have the technology to understand it.

Once the mission was deemed stable, the connectors between Chandra and Columbia were disconnected, and the Chandra remained elevated based internal battery power until its solar arrays were deployed. [4]

More Information

For an official NASA report of the Chandra’s launch activity, you can click here.

To see pictures from the Chandra launch mission, STS-93, click here to go to the NASA database of images for this flight.

For NASA press releases from 1999 – many of which detail Chandra’s findings, click here.