HOUSTON - As
the two-man crew of the International Space Station (ISS) prepares to return
home after six months in orbit, a fresh trio of astronauts is counting down to
an April launch to the orbital laboratory.
ISS
Expedition 10 commander Leroy Chiao and flight
engineer Salizhan Sharipov are
set to drop back down to Earth aboard their Soyuz 9 spacecraft on April 24 at
about 6:00 p.m. EDT (2000 GMT), effectively ending the first long-duration
spaceflight for both astronauts.
"It's been
quite an impact...watching the Earth go by there knowing how much life is
there," Chiao said to reporters here at Johnson Space Center
during a video link. "It's beautiful, even the parts where I know there is
strife and war, it looks so peaceful from here."
Meanwhile,
the astronauts of ISS Expedition 11 - led by Russian cosmonaut Sergei Krikalev with NASA
astronaut John Phillips serving as flight engineer - are spending their final
weeks on Earth conducting fit checks inside their Russian-built Soyuz
spacecraft. European Space Agency (ESA) astronaut Roberto Vittori, an ISS
visitor, will join the Expedition 11 crew during the launch.
For better and worse
Chiao and
Sharipov are in the homestretch of a mission that has
had its share of surprises.
In recent
weeks, the space station has suffered a few glitches - by now familiar to both
the crew and ground controllers - including a lost gyroscope
stabilizer due to a power glitch and an Elektron oxygen
generator
that won't quite stay on. The crew also overcame a potentially serious food shortage
early in their mission that forced them to modify their caloric intake until a
fresh Russian cargo ship arrived
on December 25, 2004. The arrival of a second
Progress cargo ship on March 2, 2005 boosted onboard food supplies.
"In terms
of consumables, [the station] is in better shape than at the mission's start,"
ISS Expedition 10 increment manager Susan Brand told SPACE.com.
The space
station's U.S-built gyroscope attitude control system, however, is a bit worse
for wear, Brand said.
The ISS is
currently relying on two functional gyroscopes - the minimum required without
resorting to Russian thrusters - after circuit breaker failed last month.
Meanwhile, the station's finicky Elektron oxygen
generator, which was working for about 30 hours over the weekend before
shutting down, has had to be repeatedly nursed by the Expedition 10 crew.
"It just
switches off every now and then," said Sharipov of
the Elektron, which he has been working with
throughout the mission. "The situation is such that we have plenty of oxygen onboard."
A long run for space veterans
Chiao and
Sharipov have been living aboard the ISS since
October, when they took over
station operations from Expedition 9's
Gennady Padalka and Michael Fincke.
Since then, they have conducted two spacewalks
to install science hardware to the station's exterior and prepare the outpost
to receive an unmanned European cargo ship due to dock sometime next year.
Though both Chiao and Sharipov are spaceflight veterans,
Expedition 10 marks the first long-duration spaceflight for both men.
Sean Roden, flight surgeon for
Expedition 10, said the station crew is in great shape and has completely
recovered from their earlier dietary constraints
during the food shortage.
"They've adapted perfectly," Roden
said of Chiao and Sharipov's
acclimation to long-duration spaceflight. "The amount of weight they lost
[during their adjusted diet] was insignificant."
Roden said the Expedition 10 astronauts
have exercised rigorously to maintain muscle strength and bone density despite
the lack of gravity aboard the ISS. An added bonus, he said, has been the
availability of a resistance exercise device resembling a set of football shoulder
pads connected to the station floor with thick elastic bands.
"This is the first mission that we've been able to use this
device during the entire mission," Roden said of the
resistance exercise device. "The equipment has performed flawlessly."
The second scientific paper based on research by ground
scientists and an ISS crew will be published this month in the April issue of
the Journal of Trauma, which the
Expedition 10 astronauts contributed to. The first scientific paper featuring
research collected by ISS astronauts appeared in the online edition of Radiology in November 2004. Data from
that study was conducted by Expedition 9 astronauts.
The next ISS crew await
The Expedition
11 crew and Vittori are currently set to launch
spaceward aboard their Soyuz TMA-6 spacecraft at about 8:45 p.m. EDT on April
14 (0045 April 15 GMT) from Baikonur Cosmodrome in Kazakhstan and arrive at the space
station two days later.
Krikalev,
Phillips, Vittori and their backup crew have
completed flight training at Baikonur and were set to
return to Russia's Star City
today, the Russian news service Interfax reported
today.
Krikalev
told reporters that he and his crew are "ready for the flight," Interfax reported.
Expedition
11 is expected to host at least one - if not two - space shuttle crews as part
of NASA's return to flight efforts. The space shuttle Discovery is currently
slated to launch toward the ISS no earlier than May 15, with its follow-up mission
- STS-121 aboard Atlantis - is scheduled to launch in mid-July. Both missions
will test new safety tools and techniques for shuttle flight.
Krikalev
and Phillips are also expected to conduct two spacewalks during their mission,
the first in U.S.
spacesuits and the second in Russian-built Orlan
suits, for station assembly and science activities.
More science aboard ISS
Don Thomas,
ISS program scientist, told reporters today that Expedition 11 will mark a
substantial rise in space station science. Not only do flight controllers plan
to loft new science racks to the ISS during the upcoming shuttle flights, but
the added launch capability of the two shuttle flights also allows researchers
a chance to resume studies that have been limited in the past due to launch
restraints.
"Over the
last few years, we have only sent about 100 pounds (45 kilograms) or so of
science equipment to the station," Thomas said, adding that the lack of shuttle
flights - which were grounded after the Columbia
accident - accounts for the low number. "During Expedition 11 we will be
launching 4,000 pounds (1,814 kilograms) of scientific equipment to the space
station."
Two Russian
cargo ships are also set to dock at the ISS during Expedition 11, with the
first - Progress 18 - set to dock on June 10 while its successor slated to
arrive on August 26.
NASA flight
controllers said today that Chiao and Sharipov will spend the next two weeks preparing for
Expedition 11's arrival. After about eight days of handover activities, the Expedition
10 crew and Vittori will board their Soyuz TMA-5
spacecraft and make the plunge Earthward.
By the end
of their mission, the Expedition 10 crew will have spent 192 days in space.
After landing on the steppes of Kazakhstan,
they will be taken to Russia's
Star City for three weeks of physical
rehabilitation to reacclimatize themselves to gravity's pull.
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