Cosmonauts successfully removed an explosive
bolt from a Russian Soyuz spacecraft during a Thursday spacewalk.
Space station commander Sergei Volkov and
flight engineer Oleg Kononenko dealt calmly with the unusual operation outside
the International Space Station (ISS) as first-time spacewalkers, despite early
troubles setting up a Strela hand-powered crane to reach the work site.
The removal of the explosive bolt represents
part of a continuing Russian investigation into what caused the two previous Soyuz
missions to go
off-course and undergo ballistic reentries during their return to Earth.
Ten of the pyro bolts typically fire to
separate the Soyuz instrument module from the return module. That allows the Soyuz
to point its heat shield downward to protect itself from the heat of reentry.
However, a mysteriously delayed separation of
the modules forced the latest three-person Soyuz crew to endure a steep
ballistic reentry and gravitational forces reaching up to 10 times those on
Earth. South Korea's first spaceflight participant, So-yeon Yi, detailed
the experience as "scary" and was briefly
hospitalized afterward for neck and back pain.
Russian engineers want to check the pyro
bolts for signs of environmental damage from electromagnetic or plasma forces
around the space station and Soyuz spacecraft. NASA officials are also
interested in the results of the investigation, because the Soyuz will provide
the only access to the space station for a time after the space
shuttle retires.
Trouble and improvisation
The two cosmonauts opened the hatch of the
Pirs airlock on the ISS at 2:48 p.m., officially beginning a roughly six-hour
spacewalk.
Delays mounted at the start of the spacewalk,
as the cosmonauts struggled to set up the Strela crane meant to carry Kononenko
to the work site.
"Strange, I had it," Kononenko said while
struggling to get his feet planted in the crane's foot restraint. Russian
mission control finally told the cosmonaut to tether himself to the crane.
The cosmonauts kept their humor, and even
remembered their third space station crewmate. U.S. astronaut Greg Chamitoff sat
inside the Soyuz during the entire spacewalk, so that he would be able to
escape from it in the unlikely case of an emergency in which the airlock used
for the spacewalk could not be re-pressurized.
"We can probably go ahead and scare Greg a
little through the window," one cosmonaut said.
Kononenko reached the Soyuz first on the
crane and did not spot any "expensive or criminal" damage to the spacecraft. He
and Volkov then took photos and placed covers on the Soyuz thrusters to prepare
for their main operation. Kononenko then used a serrated knife to cut away insulation
from the Soyuz spacecraft work site.
"We feel sorry for the vehicle." Kononenko
said in a stab at humor.
"We're not damaging it, we're healing it,"
fellow spacewalker Volkov replied, but maintained a serious tone as he warned
his crewmate to be careful with the knife.
The spacewalkers applied a set of pliers
called "dino cutters" to ground static electricity in the area, and used other
tools and even sheer force to remove an electrical locking ring, electrical
connector and wire tie that held the pyro bolt in place.
Russian mission controllers asked Volkov to
take Kononenko's place at one point, and repeatedly requested the cosmonauts to
rest and not tire themselves.
A successful return
The crowning moment of the spacewalk arrived as Volkov
used a socket wrench to unscrew the explosive pyro bolt from its housing.
Kononenko
stood by with the blast-proof case to secure the bolt, which has the power
roughly equivalent to a large M-80 rocket.
Russian mission controllers asked the cosmonauts to count
the number of turns with the socket wrench. An estimated 10 turns was needed to
remove the bolt.
"After five, please be very careful," said a Russian
mission controller.
The cosmonauts paused at eight turns as they conferred
their plan of action, and then cooperated to loosen the bolt and put it into
its secure case.
"Good! Thank God, it is in," exclaimed one cosmonaut. The
main objective was completed at 3 hours and 58 minutes into the spacewalk.
Russian mission control dictated a five minute break
"without any motions, without moving," before allowing the cosmonauts to
complete the spacewalk by placing a protective thermal blanket over the area
where insulation was cut away.
Mission controllers also decided to delay the
secondary goal of the mission to install a docking target on the Zvezda service
module. That is instead planned to occur during the second spacewalk scheduled
for July 15, when the cosmonauts are slated to outfit the Russian segment
exterior as well as install and remove science experiments.
advertisement
