Astronauts
living aboard the International Space Station were surprised by the unexpectedly
strong vibrations that rattled their orbiting lab last month, but don't believe
the event damaged their $100 billion outpost.
Space
station commander Michael Fincke of NASA said the Jan. 14 vibrations shook
objects loose from the walls during a scheduled engine burn, but it did not
immediately spark concerns over the health of the spacecraft.
"We were
definitely surprised," Fincke told SPACE.com Thursday via a video link.
"It's not usual during a reboost to see anything come off the walls."
Video
from a camera inside the space station showed equipment doors and other
objects shaking back and forth.
The vibrations
on Jan. 14 occurred during what was expected to be a routine Russian
thruster firing to boost the space station into a higher orbit. During the two-minute,
22-second maneuver, sensors aboard the space station picked up vibrations that
exceeded acceptable limits.
Michael
Suffredini, NASA's space station program manager, said
Tuesday that a subsequent analysis has shown that the vibrations did not
shorten the orbiting lab's 15-year design lifetime. Space station flight
controllers, however, did cancel another planned thruster firing slated for
Wednesday pending more study.
"Fortunately,
the results of the analysis so far shows that we haven't hurt the space
station," Fincke said. "But we certainly could have, so we're definitely going
to be very careful next time."
Fincke
described the engine burn as the strongest thrust he and his two crewmates had
felt since they launched into space last fall aboard a Russian Soyuz rocket and
NASA space shuttle. Whenever Fincke let go of a handhold in the station, the
rest of the ship would noticeably move around him as he floated in
weightlessness.
"At the
time it was quite amazing," Fincke said. "Then the harmonic vibrations started
to kick in and we saw things shaking off the walls. That was surprising, but it
didn't last very long."
The
astronauts then had to fly through the space station's cabin collecting loose
items and reattaching them to the outpost's walls, he added.
Shuttle
Discovery's delay
With the
vibration event behind them, the space station crew is preparing the orbiting
lab for the arrival of a new Russian cargo ship and the space shuttle Discovery
later this month. The unmanned cargo ship Progress 32 is slated to launch early
next week and dock at the station on Feb. 13. But the planned Feb. 12 launch of
Discovery has been delayed
at least one week as engineers evaluate a fuel flow control valve concern.
For space
station flight engineer Sandra Magnus, also of NASA, Discovery's delay means a
longer stay in orbit. Magnus arrived at the orbiting lab last November and will
return home aboard Discovery.
"Of course,
with shuttle schedules you never really want to get your heart set on a
specific date because it's a very flexible program," Magnus told SPACE.com. "Another week is fine,
they'll make the right decision when to launch the shuttle and I'll go home
whenever it arrives."
Discovery
is now slated to launch no earlier than Feb. 19 to deliver the last set of U.S.
solar arrays and Magnus's replacement, Japanese astronaut Koichi Wakata.
Earlier
this week, Magnus raided the space station's pantry to put together some
special treats during Sunday's Super Bowl showdown between the Pittsburgh
Steelers and Arizona Cardinals. Fincke, a Pittsburgh, Pa.-native who grew up in
Emsworth, is a vocal Steelers fan who beamed down video messages of support to
spur his team on during the NFL playoffs and their Super Bowl win.
"We really
didn't have a party, but Sandy did. She put together some really amazing dips
and other Super Bowl treats that we normally would have on the ground," Fincke
said. "It made the day even more special."
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