STS-116 Discovery
Next Events
November 2006
Rollover of Discovery to VAB
December 14, Thursday
6:55 p.m. EST (00:55 CET, Friday)
Launch
Image Gallery
Crew Portrait
STS116-S-002 [hi-res]
These seven astronauts take a break from training to pose for the
STS-116 crew portrait. Scheduled to launch aboard the Space Shuttle
Discovery are, front row (from the left), astronauts William A. Oefelein,
pilot; Joan E. Higginbotham, mission specialist; and Mark L. Polansky,
commander. On the back row (from the left) are astronauts Robert L.
Curbeam, Nicholas J.M. Patrick, Sunita L. Williams and the European
Space Agency's Christer Fuglesang, all mission specialists. Williams will
join Expedition 14 in progress to serve as a flight engineer aboard the
International Space Station. The crewmembers are attired in training
versions of their shuttle launch and entry suits.
Shuttle Mission STS-116: A Hard Wire Job
September 22, 2006
NASA has said it over and over again: The coming missions to finish the
International Space Station are among the hardest and most complex
ever.
But if you ask the astronauts and engineers which of the final 14 assembly
flights may be the most complex, many would point to Discovery's next
mission, set to launch in December.
"What makes this one singularly unique is the fact that we're going to
rewire the space station," Mark Polansky, Discovery's commander, said.
Since it went into orbit in 1998, the space station has been running on a
temporary electrical system. Lead Space Station Flight Director John
Curry compared it to the way you might build a house on the ground –
until your electricity is hooked up, you probably plug your saws into a
generator. That's basically what the astronauts building and living on the
station have been doing for the past eight years.
But with the installation of two new electricity-generating solar array
panels in September, all the pieces are now in place to switch to the
permanent system. At your house, it would just be a matter of unplugging
the saw from the generator and plugging it back into the wall. But in
space, it's not that easy.
"Everything will be fine – if nothing breaks," Curry said.
The plan is to send astronauts out on two spacewalks, each devoted to
rewiring half of the station. Though it sounds complicated, that part
shouldn't be too difficult. Spacewalks are inherently dangerous and should
only be done if there is no alternative, Polansky said, but as spacewalks
go, these are pretty straightforward. The astronauts will head outside,
wait for the team on the ground to send commands to switch off the
power, and then unplug the power cables and plug them in new places.
There might be the occasional stiff cable to deal with – that can happen in
the minus 200 degrees Fahrenheit of space – and the process will likely be
slow, but not especially complex.
The real pressure, Polansky said, will be on those back in Houston.
"I hold my breath every time we do spacewalks because you never know
what can happen," he said. "So I'll definitely be watching. But I don't think
I'll be as worried as the guys in Mission Control and the folks who have
been working on the hardware will be. I think I'll have a lot of company in
the worry department."
Curry confirmed that suspicion. He's been training for this mission for six
years, and he said his team couldn't be any more prepared. But when
asked what about the mission keeps him awake at night, he had no
trouble coming up with a list.
"My team is the one that has to turn everything back on and get it
running," he said.
Mission Specialists Robert Curbeam and Christer Fuglesang, wearing
training versions of the Extravehicular Mobility Unit spacesuit, participate
in an underwater simulation of extravehicular activity scheduled for the
STS-116 shuttle mission to the International Space Station.
Image credit: NASA
Theoretically, everything should go fine. But there are a few things that
could cause some big hitches. Several of them have to do with the
unpredictability of equipment that's been in space for years. For instance,
before any of the rewiring can be done, half of the solar array that's been
providing the temporary electricity must be folded up to make room for
the new solar arrays to rotate. That's never been tried before, and it may
not be as easy as it sounds.
"It's been sitting out there taking thermal cycles (moving from minus 200
degrees Fahrenheit to plus 200 degrees Fahrenheit every 45 minutes)
since November 2000," Curry said. "It's like a map – if you keep a map
out in your car for six years and then you decide to fold it up again, you
may get some waves in it or it may not fold back the same way at all."
Many of the main components of the electrical system have been flying
that long and could cause similar large headaches. It's impossible to know
for sure if the equipment will work until the power has been turned off,
rewired and turned back on. And if it doesn't work, the astronauts can't
leave it like that – the essential systems on the station would be running
on whichever half of the station has power, but without both halves they
won't have any backup.
That's not a position anyone wants to leave the station in for any longer
than necessary. So, if Mission Control flips the switch and the lights don't
all come on, the astronauts will have to try and fix whatever the problem
is before they run out of time. If they can't, then it's back to square one.
"Then I have to tell the crew, stop what you're doing and undo
everything," Curry said.
To avoid that, plans addressing possible problems are made well in
advance.
"You put all your energy into being successful and doing it safely, while
making sure you do it efficiently," Lead Shuttle Flight Director Tony
Ceccacci said. "And then you step back after you get that completed and
say, 'What if?'"
Polansky said the crew spends a lot of time training for those what ifs.
"They run through scenario after scenario," Polansky said. "Today we're
going to do a main bus switching unit checkout, tomorrow we're going to
do a pump module remove and replace. The next day we're going to a
replace a direct current-to-direct current converter unit box. None of
which we ever plan to do on orbit."
But, Ceccacci said, as much as you would like to, you can't plan for every
contingency. You look at the most probable failure, impact to mission,
complexity of recovering, then determine if you should spend the
resources to develop the fix.
If the old solar array won't fold up, the astronauts won't be able to do any
of their rewiring spacewalks until they either fold it up manually or jettison
it. If the pump that keeps the electrical system cool doesn't work, there
would only be enough time to rewire half of the station after replacing it.
But he believes NASA is up to the challenge.
"Everyone has stepped up, is prepared, and is confident that this mission
will be very successful," Ceccacci said. "As with all complex assembly
flights, it's going to be interesting."
Quelle: NASA.gov
NASA TV
Wikipedia: STS-116
Next Events
November 2006
Rollover of Discovery to VAB
December 14, Thursday
6:55 p.m. EST (00:55 CET, Friday)
Launch
Image Gallery
Crew Portrait
STS116-S-002 [hi-res]
These seven astronauts take a break from training to pose for the
STS-116 crew portrait. Scheduled to launch aboard the Space Shuttle
Discovery are, front row (from the left), astronauts William A. Oefelein,
pilot; Joan E. Higginbotham, mission specialist; and Mark L. Polansky,
commander. On the back row (from the left) are astronauts Robert L.
Curbeam, Nicholas J.M. Patrick, Sunita L. Williams and the European
Space Agency's Christer Fuglesang, all mission specialists. Williams will
join Expedition 14 in progress to serve as a flight engineer aboard the
International Space Station. The crewmembers are attired in training
versions of their shuttle launch and entry suits.
Shuttle Mission STS-116: A Hard Wire Job
September 22, 2006
NASA has said it over and over again: The coming missions to finish the
International Space Station are among the hardest and most complex
ever.
But if you ask the astronauts and engineers which of the final 14 assembly
flights may be the most complex, many would point to Discovery's next
mission, set to launch in December.
"What makes this one singularly unique is the fact that we're going to
rewire the space station," Mark Polansky, Discovery's commander, said.
Since it went into orbit in 1998, the space station has been running on a
temporary electrical system. Lead Space Station Flight Director John
Curry compared it to the way you might build a house on the ground –
until your electricity is hooked up, you probably plug your saws into a
generator. That's basically what the astronauts building and living on the
station have been doing for the past eight years.
But with the installation of two new electricity-generating solar array
panels in September, all the pieces are now in place to switch to the
permanent system. At your house, it would just be a matter of unplugging
the saw from the generator and plugging it back into the wall. But in
space, it's not that easy.
"Everything will be fine – if nothing breaks," Curry said.
The plan is to send astronauts out on two spacewalks, each devoted to
rewiring half of the station. Though it sounds complicated, that part
shouldn't be too difficult. Spacewalks are inherently dangerous and should
only be done if there is no alternative, Polansky said, but as spacewalks
go, these are pretty straightforward. The astronauts will head outside,
wait for the team on the ground to send commands to switch off the
power, and then unplug the power cables and plug them in new places.
There might be the occasional stiff cable to deal with – that can happen in
the minus 200 degrees Fahrenheit of space – and the process will likely be
slow, but not especially complex.
The real pressure, Polansky said, will be on those back in Houston.
"I hold my breath every time we do spacewalks because you never know
what can happen," he said. "So I'll definitely be watching. But I don't think
I'll be as worried as the guys in Mission Control and the folks who have
been working on the hardware will be. I think I'll have a lot of company in
the worry department."
Curry confirmed that suspicion. He's been training for this mission for six
years, and he said his team couldn't be any more prepared. But when
asked what about the mission keeps him awake at night, he had no
trouble coming up with a list.
"My team is the one that has to turn everything back on and get it
running," he said.
Mission Specialists Robert Curbeam and Christer Fuglesang, wearing
training versions of the Extravehicular Mobility Unit spacesuit, participate
in an underwater simulation of extravehicular activity scheduled for the
STS-116 shuttle mission to the International Space Station.
Image credit: NASA
Theoretically, everything should go fine. But there are a few things that
could cause some big hitches. Several of them have to do with the
unpredictability of equipment that's been in space for years. For instance,
before any of the rewiring can be done, half of the solar array that's been
providing the temporary electricity must be folded up to make room for
the new solar arrays to rotate. That's never been tried before, and it may
not be as easy as it sounds.
"It's been sitting out there taking thermal cycles (moving from minus 200
degrees Fahrenheit to plus 200 degrees Fahrenheit every 45 minutes)
since November 2000," Curry said. "It's like a map – if you keep a map
out in your car for six years and then you decide to fold it up again, you
may get some waves in it or it may not fold back the same way at all."
Many of the main components of the electrical system have been flying
that long and could cause similar large headaches. It's impossible to know
for sure if the equipment will work until the power has been turned off,
rewired and turned back on. And if it doesn't work, the astronauts can't
leave it like that – the essential systems on the station would be running
on whichever half of the station has power, but without both halves they
won't have any backup.
That's not a position anyone wants to leave the station in for any longer
than necessary. So, if Mission Control flips the switch and the lights don't
all come on, the astronauts will have to try and fix whatever the problem
is before they run out of time. If they can't, then it's back to square one.
"Then I have to tell the crew, stop what you're doing and undo
everything," Curry said.
To avoid that, plans addressing possible problems are made well in
advance.
"You put all your energy into being successful and doing it safely, while
making sure you do it efficiently," Lead Shuttle Flight Director Tony
Ceccacci said. "And then you step back after you get that completed and
say, 'What if?'"
Polansky said the crew spends a lot of time training for those what ifs.
"They run through scenario after scenario," Polansky said. "Today we're
going to do a main bus switching unit checkout, tomorrow we're going to
do a pump module remove and replace. The next day we're going to a
replace a direct current-to-direct current converter unit box. None of
which we ever plan to do on orbit."
But, Ceccacci said, as much as you would like to, you can't plan for every
contingency. You look at the most probable failure, impact to mission,
complexity of recovering, then determine if you should spend the
resources to develop the fix.
If the old solar array won't fold up, the astronauts won't be able to do any
of their rewiring spacewalks until they either fold it up manually or jettison
it. If the pump that keeps the electrical system cool doesn't work, there
would only be enough time to rewire half of the station after replacing it.
But he believes NASA is up to the challenge.
"Everyone has stepped up, is prepared, and is confident that this mission
will be very successful," Ceccacci said. "As with all complex assembly
flights, it's going to be interesting."
Quelle: NASA.gov
NASA TV
Wikipedia: STS-116
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