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STS-100 Mission Plan
The STS-100/6A mission was required to continue the outfitting of the US lab delivered on the 5A flight partially equipped and outfitted additionally on the STS-102/5A.1 mission, and launch the Space Stations Remote Manipulator System (SSRMS) to the ISS. Launch of US lab racks on multiple missions was required due to the inability of the shuttle to launch a fully equipped module to the ISS. This dates back to the 1993 addition or Russia to the ISS program and requirement to move the ISS orbit from a 28.5 degree inclination orbit to a 51.6 degree orbit accessable from Russias Baykonur cosmodrome, and lowering the weight lifting ability of the shuttle and requiring launching it mostly empty and filling it over many flights. It also allowed for gradual integration of racks into the US Lab which could happen over a longer period of time requiring fewer resources and personnel on the ground and in space.
After a normal launch the shuttle Endeavour will dock to the ISS on the third flight day and will deliver logistics to the station crew before closing hatches for assembly spacewalks. The next day, and the shuttle crew will attach the SSRMS pallet to the US Lab and connect it to attachments installed by the increment 2 crew members Voss and Helms during their EVA during the STS-102 mission. The SSRMS will be checked out by the ISS-2 crew in preparations for removing it from its launch pallet.
The SSRMS
For a detailed development events list for the SSRMS, see SSRMS Development.
The SSRMS is the Canadian Space Agency's first major hardware contribution to the International Space Station (ISS). The SSRMS is comprised of two booms, each with two 12-foot sections, joined by a hinge. There are two Latching End Effectors (LEE) for grappling, one effector mounted on each end of the arm, seven joints for movement, and four video cameras with lights. The SSRMS will be the primary means of transferring payloads between the shuttle and the station for its continuing assembly.
For a general description of the SSRMS see SSRMS component.
The next day the ISS crew will be attaching one end of the SSRMS to the ISS. The MPLM will also be lifted out of the shuttle payload bay and docked to Node-1's Nadir port allowing for the ISS crew to begin transferring Lab racks and other logistics.
The MPLM, a reusable logistics carrier and is the primary delivery system used to resupply and return station cargo requiring a pressurized environment. It is one of Italy's major contributions to the International Space Station Program. The cylindrical module is approximately 21 feet long and 15 feet in diameter, weighting almost 4.5 tons excluding its capability to hold up to 20,000 pounds of contents. Launched in the Space Shuttle's payload bay, it is docked to the International Space Station once on orbit. It will transport supplies, science experiments, spare parts and other logistical components to the International Space Station.
The next day unloading of the MPLM begins, and the SSRMS is detached from its delivery pallet and shuttle astronauts will disconnect it from the US Lab. The next day, unloading of supplies and the reloading of trash into the MPLM will continue. The ISS crew also will use the SSRMS to remove its delivery pallet from the US Lab and hand it off to the shuttle RMS which will place it back into the shuttle payload bay.
The next day the SSRMS will be exercised in how it will be used to remove a future space station Airlock module from a shuttle and placed in its position on the side of the Unity Node. The SSRMS will be the only way to dock the Airlock to the ISS since the shuttle RMS can't place the Airlock on Unity. Unloading of supplies and the reloading of trash into the MPLM will also continue.
The next day the MPLM will be closed and removed from the station and put back into the shuttle payload bay. The next day the shuttle will undock and fly away from the station. After a day of checkout and preparations for landing, the shuttle will land. |
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Mission Results
The mission was going well until the SSRMS was to hand-off the pallet to the shuttle RMS. This was delayed due to a bad software load installed into the US segments Command and Control computers. The US segment has one computer as a primary and one serves as a 'warm' backup, additional computers are in standby to serve as backups if the primary malfunctions. After being loaded with new software, the primary computer
1. C&C-1 dropped off line Wednesday night after experiencing hard
disk access problems. C&C-2 automatically took over, switching from
backup to primary mode. C&C-3 switched to standby.
2. C&C-2 operated normally for several hours and then experienced
hard disk errors Wednesday morning.
3. Flight controllers sent commands ordering C&C-3 to take over as
the primary computer in the command set.
4. C&C-3 suffered hard disk problems and dropped off line, taking
the station's main communications system down with it.
5. Engineers finally succeed in uploading commands late Wednesday
that effectively shut C&C-3 down in a bid to force C&C-2 back into
action. That appeared to work, but 40 minutes later C&C-2 failed
again.
6. With all three computers down, the node computers launched
Mighty Mouse to power cycle all three C&C computers.
7. C&C-2 reboots normally and appears healthy.
To recap the basic problem: As of 7:45 p.m., just one of the
Destiny lab module's three command-and-control computers was
operational. In addition, two computers in the Unity module were off
line because of a timing synchronization problem.
The two node computers, running an emergency program called Mighty
Mouse, were responsible for getting C&C-2 back in operation in
Destiny after all three of the station's command computers shut down
in domino fashion Tuesday night and Wednesday. But C&C-2's
input-output capability was deliberately inhibited while engineers
studied the situation.
As a result, the computer's internal clock got out of synch with
clocks in the Unity computers. When engineers attempted to reboot the
Unity machines this afternoon, they immediately shut down, believing
their was a problem.
04/28/01, Update: C&C-2 hard drive error reported
Engineers have successfully loaded critical software into a second
command-and-control computer aboard the international space station.
But they are looking into an apparent glitch with the hard drive in
the computer that was already operating, a potential setback on the
station's road to recovery.
An error message saying the C&C-2 computer's mass storage device
was "inaccessible" popped up around 10:25 a.m. The station astronauts
were asked if anyone had typed any commands into laptop computers
tied into the central computer system, but astronaut Susan Helms
reported that no one had done anything that might have prompted the
error message.
In the meantime, engineers finally completed uplinking a full set
of programs into the DRAM memory of C&C-3 after unsuccessful efforts
earlier. They now are in the process of dumping the contents of
memory to verify a good load.
C&C-3's hard drive is not working properly following massive
computer problems earlier this week. But the machine's DRAM memory is
able to hold the core elements of the station's command-and-control
software. Assuming the memory dump shows now problems, C&C-3 will be
able to serve as a backup to C&C-2.
C&C-2's hard drive has been working normally since the computer
was successfully restarted Thursday. But all of the computers in the
C&C set were affected by hard drive errors prior to their initial
failures. The nature of the problem that generated today's error
message is not yet known.
Because neither of the lab's operational C&C computers could use
its built-in hard drive, the astronauts and ground controllers had to
take turns issuing commands to the arm and its systems, working
step-by-step through a tedious checklist to make sure they didn't
inadvertently cause additional computer problems.
One hour and five minutes after the procedure began, Voss moved a
hand controller on a computer work station in the Destiny laboratory
module to detach the Canadarm 2 from the Spacelab Pallet, completing
the handoff at 5:06 p.m. as the shuttle sailed over the western
Indian Ocean in orbital darkness.
The astronauts originally planned to carry out a series of tests
with the new space crane, including a dress rehearsal of maneuvers
that will be required in June to install the station's main airlock.
But mission manages decided Friday to defer the airlock dry run and
to power down the arm after today's pallet handoff. Flight controllers still need to initialize and reload a third C&C
computer - C&C-1 - with command software and resolve questions about
C&C-2's hard disk. While both C&C-2 and 3 currently are operational,
neither computer can access its hard disk.
That was a known problem with C&C-3 and engineers loaded software
directly into DRAM memory. But C&C-2 suddenly stopped recognizing its
previously operational hard drive early today and that situation has
not yet been resolved.
04/29/01, Update: Unlikely dual hardware failures may
be responsible for computer shutdowns
After five days of extensive trouble shooting, engineers now
believe the culprit responsible for crippling the international space
station's computer system was the unlikely, near-simultaneous
failures of two critical hard drives.
The station is equipped with three command-and-control computers,
called C&C MDMs, that oversee the operation of the lab's stabilizing
gyroscopes, its high-speed communications links with Earth, the
station's robot arm and other critical systems.
Each computer uses an internal hard drive to store programs and
system software. Only one computer is in control at any given moment
with a second serving as a hot backup and the third in standby.
Late Tuesday, C&C-1 suddenly dropped off line. C&C-2, which was
the backup machine then switched to primary mode but it, too,
experienced hard drive errors and flight controllers decided to call
up C&C-3. That computer promptly failed.
Engineers now believe the hard drive problem with C&C-2 was a
known issue and not an outright failure. The other two drives
apparently failed.
C&C-2's hard drive ultimately was restored and that computer is
fully operational in primary mode. Flight controllers then uplinked
critical C&C software into C&C-3's dynamic random access (DRAM)
memory and that machine - sans hard drive - is considered operational.
C&C-1 was replaced with an identical payload computer. DRAM in the
new C&C-1 computer has been loaded with command software, but
engineers have not yet been able to reformat its hard drive. They
hope to do so shortly.
Larry McWhorter, deputy manager of the avionics and software
office at the Johnson Space Center in Houston, briefed the station
astronauts today on the progress of the troubleshooting and plans to
ensure similar failures do not happen in the future.
"What we found in going through the scenarios is that both C&C-1
and C&C-3 appear to have failed disk drives," he said. "Neither of
the drives are spinning, so they would be of no use and no way of
getting files from them.
"We know that you have R&R'd C&C-1 and we're bringing it back to
the ground to have Honeywell, who is the vendor, do a complete review
of the box and to identify what the problem is there. The signature
of C&C-3, looking at the data, is very similar to C&C-1, so we hope
to learn from 1 what's going on in 3.
"C&C-2, that disk appears to be functioning nominally," McWhorter
said. "There've been some nuisance items that have come up and we
have procedures to work through and C&C-2 is functioning fine at this
point in time.
"We have taken C&C-3, which has the failed disk, and have loaded
the necessary software into DRAM. That is functioning at this time as
the backup in the case that C&C-2 had a failure. We've also loaded
into C&C-1 the DRAM software. We've made one attempt so far to format
the disk so that we can transfer all the files from C&C-2 to C&C-1
that we would need to make it operate nominally. We had a failure in
that reformatting process.
"One comment: When we've done this process (on the ground), we
normally have seen it take two to three attempts to get through this
full format of the disk. So this failure was not a surprise and we're
going to continue to work to get that disk formatted so C&C-1 will
have full capability."
Station astronaut James Voss then asked the obvious question.
"Larry, had you all seen some degradation or something that would
have led you to believe we would have had two failures like this at
almost the same time?" Voss asked. "It just seems kind of strange
that two pieces of hardware would fail like this in the same way at
just about the same time."
"It was a total surprise to us," McWhorter said. "We've not seen
anything in the behavior of either piece of hardware that would have
led us to suspect the failures were coming. That's why we're very
interested in getting C&C-1 down to the ground so we can understand
what happened to it."
He said engineers are continuing work to "get a better handle on
the long-term solution."
"The first thing, we'll continue to try to understand the root
cause of what happened to these two units, and that would include the
work of diagnosing the failure in C&C-1 when it gets to the ground,"
he said. "We're also going to have a group look at how to build a new
C&C out of the spares that you have on orbit. ... There's enough
hardware there to build another C&C.
"We're also working to manifest a new controller or disk drive on
a downstream flight to have another one on orbit to replace the one
that's coming down," he continued. "The other thing we're doing is
trying to look at how we could more rapidly get the MDM testing
hardware that's being built and verified over the next few months on
board so that we would have it to test MDMs that fail on orbit or
cause problems."
And finally, NASA is looking at ways to accelerate development and
delivery of solid state memory modules that could replace the hard
drives altogether.
4/28
The Soyuz TM-32 spacecraft was launched Saturday from the Baikonur
Cosmodrome in Kazakhstan. It is scheduled to dock with the
international space station Monday at 3:52 a.m. EDT. Docking and
hatch opening, scheduled for around 5:22 a.m., are expected to be
carried live on NASA television.
4/29
With shuttle pilot Jeffrey Ashby at the controls, Endeavour
undocked from the 120-ton station complex at 1:34 p.m
4/30
The Soyuz TM-32 spacecraft carrying U.S. millionaire space tourist
Dennis Tito and two cosmonaut crewmates successfully docked with the
international space station at 3:58 a.m. today as the two vehicles
sailed 240 miles above central Asia.
With commander Talgat Musabayev at the controls, the three-seat
Soyuz capsule made an automated approach to the station, using its
KURS radar system to lock onto a docking target at the Zarya module's
Earth-facing port.
4/30
After extensive troubleshooting, engineers successfully recovered
C&C-2, along with its internal hard drive, on Thursday. C&C-3
suffered an outright hard drive failure, but critical control
software was reloaded directly into its DRAM memory and the computer
was switched into backup mode.
C&C-1 was replaced with an identical computer used to control
experiments. The new computer's DRAM was loaded with the necessary
software, but its hard drive initially failed to reformat, preventing
controllers from loading critical software onto the disk.
Early today, flight controllers told the astronauts they had
finally succeeded in reformatting the disk, giving the station three
operational command-and-control computers and two operational hard
drives.
"That is great news about C&C-1," Helms radioed. "You guys do great work."
After diagnostic tests are complete, C&C-1 will be switched to
backup mode and C&C-3 will be switched into standby mode, ready to
take over if both of the other machines fail.
The station can operate with just one C&C computer and one
operational hard drive. But flight controllers want at least one
fully operational backup machine while troubleshooters on the ground
continue searching for the cause of the original failures last week.
The hard drives are crucial because they store robot arm control
software and programs for other systems, including the station's
Ku-band communications links with Earth and the command displays used
by laptop computers that control various aspects of station operation.
05/01/01, Update: Shuttle Endeavour returns to Earth
Diverted by bad weather in Florida, the Endeavour astronauts
glided to a smooth California landing today, leaving the repaired
international space station behind in orbit and setting the stage for
a milestone mission in June to complete the lab's initial assembly.
With commander Kent Rominger and pilot Jeffrey Ashby at the
controls, the black-and-white spaceplane crossed the California
coastline above Los Angeles, descending steeply as it streaked toward
Edwards Air Force Base to the northeast.
Guiding the shuttle through a steep right overhead turn, Rominger
lined up on runway 22, Ashby dropped the ship's landing gear and
Endeavour floated to a tire-smoking touchdown at 12:10:42 p.m. EDT.
---
recap
The 57-foot-long robot arm was installed on the Destiny laboratory
module April 22 and temporarily wired into the station's power grid
by Parazynski and Hadfield during the first of two spacewalks. The
job was completed during a second spacewalk last Tuesday.
But that night, one of the station's three command-and-control
computers suddenly shut down. A second C&C computer was brought on
line but later the next morning, it began acting erratically and
flight controllers switched to C&C-3.
To everyone's surprise, the third computer experienced hard drive
problems promptly shut down itself, leaving the station without an
operational C&C computer.
Robot arm checkout was put on hold while a team of engineers at
the Johnson Space Center began an intensive troubleshooting effort to
pin down what had gone wrong.
Endeavour originally was scheduled to undock Saturday, but the
mission was extended one day to permit additional troubleshooting.
C&C-2 eventually was coaxed back into action. C&C-3's hard drive
failed outright, but engineers were able to load critical software
directly into DRAM memory to recover additional redundancy. C&C-1 was
declared a failure and replaced with a payload control computer that
later was loaded with C&C software.
In the meantime, the Soyuz TM-32 spacecraft carrying millionaire
space tourist Dennis Tito blasted off Saturday from the Baikonur
Cosmodrome in Kazakhstan after a last-minute compromise between NASA
and the Russian Space Agency.
The Russians agreed the day before to delay the Soyuz docking by
one day if NASA needed an additional day for computer
troubleshooting. As it turned out, engineers successfully reactivated
all three C&C computers and one of two hard drives, clearing
Endeavour to depart Sunday as planned.
Since then, the C&C-1 computer's hard drive has been successfully
reformatted. C&C-2's hard drive is fully operational as well, but
C&C-3 continues to operate in DRAM mode. Its hard disk is believed to
have suffered a hardware failure of some sort.
Ground engineers have not yet identified the cause of the original
failures and are still in the processing of validating software and
reloading critical programs into the C&C system. The station
astronauts, meanwhile, are taking a bit of time off, showing Tito
around and keeping him out of trouble.
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C&C computer#1 was removed and returned to Earth on the STS-100 mission. It was delivered to Honeywell for failure analysis
C&C 3 has a bad hard disk, may be replaced by a on board spare
KU-band was restored just before
Payload MDM#1 was restored after being pressed into service as a C&C backup, replaceing the removed C&C#1
Payload MDM#2 was off when it all started and was pressed into service as MDM#1 was converted into a C&C backup
C&C2 data is being backed up onto C&C1 so that it can become a fully functional backup |
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