The U.S. space program plunged into further disarray Friday when a mysterious fuel leak grounded NASA's entire shuttle fleet, while a Senate panel was opening a probe into how the Hubble space telescope had become partially blinded.
NASA canceled plans to set a launch date for the shuttle Atlantis after it sprang a leak during a special fueling test Friday morning. The leak resembled one that grounded Columbia and the $148 million Astro Observatory May 29.
William B. Lenoir, chief of spaceflight for the National Aeronautics and Space Administration, said a planned July 15 flight of Atlantis on a secret military mission had been postponed indefinitely because of the leak.
Several other flights are on hold because the shuttles are unsafe to fly, Lenoir told a news conference at NASA's Kennedy Space Center in Cape Canaveral, Fla.
In Washington, meanwhile, a Senate committee opened hearings into how a flawed mirror on the Hubble Space Telescope went undetected, delaying for years and perhaps indefinitely 40 percent of its planned experiments.
It was unclear whether the grounding of the shuttle fleet would delay a Hubble repair mission set for 1993.
NASA chief scientist Lennard Fisk said the space agency would shoulder the blame for failing to test the mirror prior to launch. He said the test would have added hundreds of millions of dollars to the cost of the project, begun a decade ago, and was judged not to be worth the money.
"There's no question we won't fly (any shuttle) until we understand it and have it fixed and have tested and verified it and we're ready," Lenoir told reporters.
Sensors at the Atlantis launch pad detected abnormally high levels of liquid hydrogen propellant in a line that transfers fuel between the tank and the Atlantis shuttle's three rocket engines.
Engineers still have not found the exact location of the leak in Columbia, which was moved off the launch pad for inspection and repairs.
Atlantis had been expected to lift off July 15 with five astronauts and a classified cargo that civilian experts have described as a missile-warning satellite.