Icy propellant trickled from a leaking jet aboard Discovery on Friday as the shuttle chased a Russian space station around Earth for a historic rendezvous early next week.
Mission Control assured the five Americans and one Russian aboard Discovery that the leak was minor and, if it did not worsen, would have no impact on Monday’s close encounter between the shuttle and the orbiting Mir station.
If the leakage increases, the crew will have to go to the extreme measure of shutting off all three jets in that section. Discovery still would rendezvous with Mir, but would have to stay at least 1,000 feet away instead of coming within 35 feet.
“We’re hopeful that the leak will resolve itself and stop,” Mission Control told the astronauts as they wrapped up their first workday in space. “Right now, it does not affect your rendezvous.”
The steering jet failed and began leaking nitrogen tetroxide shortly after Discovery reached orbit early Friday.
Commander James Wetherbee and pilot Eileen Collins, the first woman to pilot a U.S. spaceship, turned the seeping jet toward the sun to melt any frozen fuel that might be preventing the thruster valve from closing. This has always stopped leaks before.
After several hours, Wetherbee still could see propellant scattering in all directions.
“As we look at the darkness of space, you can see the snow coming out of the aft end, that continues to come like a very, very small leak,” he said.
The jet was losing 2 pounds to 3 pounds of propellant per hour, considered a manageable rate of seepage, NASA said. It posed no safety hazard to the shuttle or crew.
Discovery’s crew was instructed to keep the leaking jet above 40 degrees Fahrenheit. The temperature of the thruster was in the high 50s Friday afternoon.
The leaking thruster is one of two that failed. They are among 38 large steering jets on Discovery.
The 250-mile-high rendezvous is the top priority of the mission.