By Yuri Karash MOSCOW The long-awaited Russian living quarters for the International Space Station (ISS) will be launched next week despite an engine-sensor problem that cropped up on the July 5 flight of a Proton rocket, U.S. and Russian space officials said Friday.
Considered a crucial building block for the now vacant station, the so-called Zvezda service module is scheduled to blast off atop a nearly identical Proton rocket next Wednesday.
Watch NASA animation of the Russian Service Module Zvezda docking with the ISS.
Senior U.S. and Russian space officials gave the green light for the flight after an 11th-hour investigation into an apparent problem with the second-stage engine of a Proton rocket that lofted a Russian military satellite into orbit Tuesday.
Sergei Shayevich, a senior program manager with Khrunichev State Research and Production Center.
"There was some malfunctioning of the second stage, but we have already investigated the case and we have a full understanding of the problem," said Sergei Shayevich, a senior program manager with Khrunichev State Research and Production Center, which manufactures Proton rockets and also built the Zvezda module.
"Its a minor problem. Weve never encountered such a problem before. But I want to say the space center Khrunichev is positive that we will have no problem with the [Zvezda] launch."
Two years behind schedule
Already more than two years behind schedule, the Zvezda launch has been held up for the past year because of a pair of Proton rocket failures in 1999. Both were blamed on second-stage engine failures, and Zvezda is to be launched atop a Proton rocket.
Khrunichev and its engine manufacturer Vorornezh Mechanical Plant spent about four months investigating the near-identical failures, both of which were traced to poor workmanship when the engines were built.
In both cases, debris inadvertently left within the engines caught up in the power plants, triggering catastrophic in-flight explosions.
Proton rocket engines since then have been modified to prevent a recurrence. But with the future of the $60 billion International Space Station program hanging in the balance, U.S. and Russian space officials agreed to launch two modified Proton rockets prior to embarking on the crucial Zvezda flight.
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The first of those flights came off without a hitch in early June. The second came Tuesday, and while the satellite-delivery mission was a success, a postflight analysis showed pressures within the rockets second-stage engine appeared to be lower-than-normal, Shayevich said.
Faulty sensor
Fueling of the Zvezda module which also will serve as the initial command center for the international station was delayed earlier this week while Khrunichev engineers investigated the problem. Ultimately, engineers traced the glitch to a faulty sensor rather than an actual problem with the rockets second-stage engine.
The Zvezda service module
"The fact that the satellite was inserted into space and got into the right position is good proof that [the apparent problem] didnt affect the overall mission," Shayevich said, adding that the balky sensor was not related to Proton engine modifications.
"Its a minor case, and it does not have any overall effect on the whole program."
NASA officials were briefed on the engine issue Thursday, and then again early Friday before a Russian state commission cleared Zvezda for launch on a modified Proton.
That Proton which stands 180 feet (55 meters) tall and weighs 1.5 million pounds (700,000 kilograms) is scheduled to be rolled out to its launch pad early Saturday at Baikonur Cosmodrome in Kazakhstan.
Launch remains scheduled for 12:56 a.m. Eastern Daylight Time (04:56 GMT) Wednesday.
-- Cape Canaveral Bureau Chief Todd Halvorson contributed to this story.
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