Early Engine Cutoff Foils Attempts To Move ISS to Higher Orbit

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  Space News Business

Early Engine Cutoff Foils Attempts To Move ISS to Higher Orbit

By TARIQ MALIK
Space New Coorespondent
posted: 24 October 2005
01:22 pm ET


A Russian spacecraft stopped short of boosting the international space station (ISS) into a higher orbit Oct. 18 when its engines unexpectedly shut down in mid-maneuver, Russian space officials said.

“After the first turn-on of the engines … they turned off spontaneously,” an official for Russia’s Federal Space Agency told the Interfax News Agency.

The failed orbital maneuver poses no danger to the ISS or its two-astronaut crew, Expedition 12 commander Bill McArthur and flight engineer Valery Tokarev, and engineers are currently studying the glitch, according to a Federal Space Agency statement.

“There is no forecast at the moment as to when they would try again,” NASA spokesman Rob Navias said in a telephone interview from Johnson Space Center in Houston . “[But] there’s no urgency to do this.”

Russian and U.S. space station flight controllers expected to perform two engine burns Oct. 18 using the Progress 19 spacecraft’s engines to raise the space station into a higher orbit, an operation that takes place a couple of times a year to keep the massive facility from drifting back toward Earth. The spacecraft is docked at the aft end of the space station’s Zvezda module.

The engine burns, each scheduled to run 11 minutes and 40 seconds, were expected to raise the space station into an orbit about 360 kilometers at its highest point, a bit higher that the station’s current orbital peak of 354 kilometers , NASA officials said Oct. 18.

But the Progress engines switched off less than two minutes into the first burn, NASA officials said, adding that there appeared to be a communications problem between the spacecraft’s thrusters and Russian navigation computers, which shut down the engines as designed due to the data dropout.

The brief engine burn did accelerate the ISS by about 0.31 meters per second and raised the lowest point of the station’s orbit — 339 kilometers — by about 1.1 kilometers , according to NASA officials.

Other engines could be used to boost the space station’s orbit, but Russian space officials are still evaluating the glitch, the Federal Space Agency said.

The altitude-raising maneuver was slated to place the station into the proper position for a second orbital boost later this year that would set up the space station to receive another unmanned Russian-built cargo ship — Progress 20 — slated to launch toward the space station on Dec. 21, Navias said .

Progress 20 will ferry vital supplies, spare parts and equipment to McArthur and Tokarev, who began their six-month tour aboard the ISS this month.

Comments: tmalik@space.com