CAPE CANAVERAL, Fla. -- The International Space Station's crew might be forced to stay in space for several extra weeks if orbital maneuvering engines on shuttle Endeavour have to be removed for special safety inspections, NASA officials said Monday.
Seven shuttle flights in 2002, meanwhile, all face launch delays of two weeks to a month because of extra work that needs to be done on shuttle Columbia, which is being readied for a return to flight after a lengthy overhaul in California.
In space now since August, the station's current crew -- U.S. astronaut Frank Culbertson and Russian cosmonauts Vladimir Dezhurov and Mikhail Turin -- remain scheduled to return to Earth Dec. 10 aboard Endeavour.
That plan, however, could change if NASA engineers determine that the ship's two hump-like orbital maneuvering system pods must be removed for extra inspections.
"There's a potential for a slip of the launch by at least weeks," said James Hartsfield, a spokesman for NASA's Johnson Space Center in Houston. "I don't know by how many."
Here's the situation:
Engineers inspecting Columbia discovered a problem with one of the 12 attachment points for the shuttle's twin orbital maneuvering engines, which are housed in pods on either side of the ship's vertical stabilizer, or tail fin.
Large bolts are driven through each of the attach points to secure the pods to the orbiter. They are routed through a bowl-shaped support plate that is attached to the skin of the pods by smaller bolts that measure 5/16th-of-an-inch (0.8-centimeters).During an inspection of an attachment point on one of Columbia's pods, engineers discovered that bolt holes associated with the bowl-shaped support plate were elongated -- perhaps the result of improper machining.
Consequently, bolts driven through the holes were found to be a bit loose, raising concerns about the structural strength of the attach point.
A subsequent inspection of Columbia's other pod uncovered the same problem. And while both of the pods subsequently were fixed, NASA engineers have launched an analysis aimed at determining whether the pods on Endeavour, Atlantis and Discovery should be inspected prior to the next flights of those shuttles.
Located at the aft center of the pod, this particular attachment point bears the brunt of most of the aerodynamic forces encountered during a shuttle's thundering climb into orbit.
A failure of the attach point during a shuttle launch could damage structural metal within the pod and potentially have a ripple effect, causing other attach points to weaken or break in flight.
"It's something we don't want to have happen," Hartsfield said. "We're just trying to ensure that it's strong enough that nothing happens."
Tests are being conducted this week to determine whether an elongated bolt hole in fact could lead to pod damage in flight or a situation that might endanger a shuttle and its crew.
Those tests will weigh heavily on a subsequent decision on whether the pods on Endeavour will have to be removed for inspections, a move that potentially could delay the shuttle planned Nov. 29 launch -- and the station crew's return to Earth -- until next year.
NASA program managers, meanwhile, already are planning to delay a series of 2002 shuttle flights in order to complete work required prior to the next launch of Columbia, which now is scheduled to take off Jan. 17 on a Hubble Space Telescope servicing mission.
NASA's oldest orbiter returned to Kennedy Space Center earlier this year after a 17-month overhaul at a shuttle assembly plant in Palmdale, Calif. Engineers since have determined that it will take more time than originally anticipated to prepare the shuttle for its return to flight.
The Hubble servicing mission, consequently, likely will be delayed until mid-February, and that postponement is likely to push six additional 2002 shuttle flights back accordingly.
A planned Feb. 28 launch of Atlantis on a space station construction mission likely will be delayed until around March 21, and a planned April 18 launch of Endeavour on another outpost assembly mission likely will fall back to around May 5.
Also facing delays: a May 23 launch of Columbia on a research mission, and flights to the station now scheduled for launches on Atlantis, Endeavour and Discovery on July 11, Aug. 22 and Nov. 21, 2002, respectively.
Firm decisions on all the upcoming shuttle missions could be made by the end of this week.
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