October 30, 2007
A Very Significant Anomaly
Today's scheduled EVA 3 promised to be one of the most demanding, even before an extra task was added. It lived up to expectations in that regard. However, the real excitement began after the spacewalkers had completed their tasks.
All major objectives of the 7 hour and 8 minute spacewalk were met. After discovering what appeared to be metal shavings inside the starboard Solar Alpha Rotary Joint (SARJ) during EVA 2, an inspection of the port SARJ was added to EVA 3. Spacewalker Scott Parazynski performed the inspection and gave the unit a clean bill of health, noting that the race ring was completely clean and that there was no evidence of any unwanted particles anywhere in the unit.
The major task of EVA 3 was the movement of the P6 truss to its permanent position next to the P5 truss. P6 was successfully moved and bolted in place, and electrically connected. A photovoltaic radiator was also deployed. At that point control transferred to Houston to initiate redeployment of the P6 2B and 4B solar arrays. After depoyment of both arrays was begun, control reverted to the crew inside the ISS. The deployment of the 2B array proceeded without a hitch. However, when the 4B array was almost completely deployed, the crew spotted an anomaly and aborted the deployment.
A tear in the 4B solar array about two and a half feet long was noticed. ISS Program Manager Mike Suffredini characterized the tear as a very significant anomaly. Deciding what to do about it is causing the folks in Houston to burn the midnight oil. Even if nothing is done, the 4B array will still be able to deliver 97% of its rated power. However, if the problem can be corrected before the shuttle leaves, it would be better than leaving things as they are. As a result, an extra flight day has been added to the schedule between EVA 4 and EVA 5. EVA 4 will include a detailed examination of the troublesome starboard SARJ.
After Spacewalker Douglas H. "Wheels" Wheelock returned from today's spacewalk, he noticed a hole in his right glove. Holes and cuts in EVA gloves are a concern, if they penetrate all the way through the glove material. That did not happen this time, but is worrysome nonetheless. Venting your spacesuit's air to space through a glove hole is probably something you would want to avoid if you were in Wheels' position. There are apparently a number of sharp edges on the exterior of the ISS that spacewalkers must avoid. Unfortunately, some of these sharp edges may be located on the hand-holds that are specifically designed for spacewalkers to grab. Micrometeoroid damage can convert a carefully designed hand-hold into a hazard. Now that the cut glove situation has cropped up more than once, I expect procedures may be changed to adjust. The gloves may also be in for an upgrade at some time in the future.
Allen G. Taylor
Posted by allen.taylor at 02:53 AM
October 29, 2007
Updated Spacewalk Plans
As you may have heard, STS-120 spacewalkers Scott Parazynski and Dan Tani uncovered a problem in the starboard Solar Alpha Rotary Joint (SARJ) on Sunday. This joint is what allows the solar array wings to rotate around the y-axis of the station. (The x-axis runs along the length of the modules, and the y axis along the truss with the origin at Z1 atop the Unity node. Z is up and –z points toward Earth.) The joint has not been working properly, and Mission Control asked for an inspection.
Tani removed some covers and found “filings” jamming up the works. He used some tape to capture samples of these particles. Station Commander Peggy Whitson used paper and a magnet to find out that these particles are magnetic.
In Monday’s press briefing, ISS Program Manager Mike Suffredini said that the particles being magnetic rules out them coming from the aluminized Mylar thermal covers and indicates they are probably from the steel bearings or “race” inside the joint. I am not an engineer, and I’m sorry that I cannot tell you what a “race” is other than it is a steel part near the gear teeth. The teeth are the brakes that hold the SARJ in place after it has rotated to a new position. Some wear is expected on these teeth over time, and Mr. Suffredini said that life-time testing had shown some particulates—but nothing like the number seen by Tani.
Other parts of the SARJ that may be contributing to the problem include something called a TBA, trundle-bearing assembly, and a ?joggle that is a U-shaped piece. The ?joggle has a thousand-pound load on it. If the TBA turns out to be the source of the problem, then there is a procedure to replace it with a spare. The next shuttle flight would have to take it up. Mr. Suffredini called this replacement a “sophisticated effort,” meaning it is probably one heck of an EVA script, and one that the crew has not been trained to do.
The plan is to take some time from EVA 3 on Tuesday to inspect the port SARJ. This joint is working smoothly, and so will provide a comparison to the balky starboard joint. Ironically, the port joint is older than the starboard one. The port joint was installed last December, and the starboard just this past June. Mr. Suffredini also said it does not look like a wearing-down build-up kind of problem because the performance has changed in a stepwise fashion, not gradually gotten worse as it would if there were a gradual buildup of filings.
During EVA 3, Scott will take a tape sample of the port array to check for particles whether he sees any or not. A window of about 40 minutes has been carved out the EVA for this inspection. The rest of the EVA is devoted to the important job of attaching the P6 solar wing and getting it unfurled and working. If the starboard array is not able to rotate and track the sun (and thus produces much less power), then having this port array in full operation becomes even more critical. Therefore, if there is a problem with the array deployment, it will take priority over any SARJ work planned for the EVA 4 on Thursday.
The array deployment was originally scheduled to begin around 1:30 p.m. Eastern time. The port SARJ inspection is supposedly added somewhere in the middle of the EVA, so this time may be changed. (DONE EARLY! AROUND 11:30 Eastern!)
Assuming that the P6 attachment and deployment goes well Tuesday, then Thursday’s EVA will be devoted to a thorough inspection of the starboard joint. The plan is to remove all 22 thermal covers around the 10-foot diameter joint and look for filings and take samples. This will take longer than the previously planned spacewalk, and will thus require Friday's spacewalk by the station crew to be delayed a day to prepare the airlock.
Flight Extension/Flight Delay
To fit in the long EVA 4, the shuttle flight will be extended one day. The question was asked if the P6 deployment requires work on EVA 4, will another 6th EVA (a record) be added to deal with the starboard SARJ, and the answer was undecided., but probably not. To do so might jeopardize the launch of the next shuttle flight, planned for December 6. That launch will take the Columbus module up. Harmony must be moved to its permanent position between the PMA and Destiny before Columbus can be attached. EVA 5 by the station crew is therefore in the critical path of this action, and if delayed, would delay the launch of Columbus. Also, EVA 5 requires that the power-sharing system that allows the shuttle to use station power and stay longer, has to be disconnected. So a new EVA would have to be added in between EVA 4 and 5, and require 2 days addition to the shuttle flight, and that would impact the next shuttle launch. Just moving Friday’s EVA to Saturday may mean that the launch will slip from December 6 to 7. Constraints on the beta angle, the angle of the sun with the orbit plane of the station, require that launch to be no later than December 13.
Mr. Suffredini indicated that even if the starboard SARJ is locked in place and won’t allow the starboard array to rotate, with port side working, there is sufficient power for Columbus to be added. However, the Japanese module that is planned to go up next spring, will require the starboard arrays to rotate to produce the required power levels. So while the SARJ problem is serious, it will not cause any immediate change in operations on the station.
Space exploration is never easy, and challenges are to be expected. The good news is that the crew and flight control teams are fantastic problem solvers. I sure appreciate their willingness to let us “look over their shoulders” while they go through the process. I certainly wish them well!
Posted by m_dyson at 01:05 PM
October 28, 2007
October 28, 2007
Today Scott Parazynski and Dan Tani performed the mission's second spacewalk. They had a full schedule of required tasks, plus three "add-on" inspections. The big job was detatching the huge P6 truss from the Z1 segment and directing it to a temporary parking position, with the help of the station's robotic arm. During a later spacewalk it will be moved to its final resting place on the port side of the station.
In an effort to possibly see what might have caused cuts to astronaut gloves on previous missions, handrails were inspected. Some pitting, possibly due to micrometioroid impacts was noted, but nothing that looked like it was sharp enough to cut a spacewalker's glove.
The biggest add-on to the schedule had Dan Tani inspecting the starboard Solar Alpha Rotary Joint (SARJ). This is a critical piece of equipment, since it controls the rotation of the starboard solar panels, enabling them to track the sun as the station moves along its orbital track. Proper solar panel orientation is vital to supplying the station with the electricity it needs. For the past 50 days, the starboard SARJ has required an ever increasing amount of power in order to do its job.
Tani did a 360-degree visual inspection of the SARJ and saw nothing unusual. Mission control then directed him to remove the cover from the device and look inside. When he did, he noticed what appeared to be metal shavings scattered around the unit. Rather than floating in space, these anomalous particles were adhering to the surfaces of the SARJ as if they were magnetized. Tani gathered some of the particles with tape and then restored the cover. The particles will be analyzed to the extent possible in the station and then taken back to Houston for a thorough analysis and determination of what they are and what should be done about them. Since the startup current needed to move the SARJ is slowly increasing and may ultimately exceed what is available, some resolution must be found in the long term. Mission management is confident that any rquired repair will be possible, using spare parts that are already on the station.
While performing one of the scheduled maintenance tasks, a spacewalker lost an O-ring to space, thus adding one more element to the cloud of orbital debris that encircles the planet.
All in all, today's spacewalk was a success, with all major objectives met.
Allen G. Taylor
Posted by allen.taylor at 03:27 PM
October 26, 2007
With the successful attachment of the new Harmony module by spacewalkers Scott Parazynski and Doug Wheelock today, the astronauts plan to enter their new addition for the first time Saturday. Harmony is currently attached “across the hall (Unity node)” from the Quest airlock. The crew won’t want to get too comfortable with it in that position, though. It is going to be moved soon after the shuttle departs.
The reason it can’t be attached to its permanent position now is that the shuttle is docked to the Pressurized Mating Adaptor (PMA) which is attached to the Destiny lab. Harmony will eventually be between Destiny and the PMA.
Moving all the pieces around will require some nifty robotic maneuvering which we’ve seen a lot of on this mission. After the shuttle departs, the Pressurized Mating Adaptor (PMA), that crooked funnel-looking thing that attaches to the shuttle’s airlock, will be detached from Destiny and moved around to the port side and attached to Harmony. Then Harmony, with the PMA attached, will be detached from the Unity node and swung around to the front of Destiny where the PMA used to be. So Harmony will end up between Destiny and the PMA.
When the shuttle arrives in December with the Columbus module, it will dock to the PMA as usual. (The shuttle can only dock to the PMA. The Soyuz have several docking ports.) Columbus will be attached to the starboard side of Harmony. In the spring (April) the Japanese Kibo will be added on the port side of Harmony.
The Italians built Harmony, and also the part of the station that will replace it on the port side of Unity: a giant segmented picture window called the cupola. This window’s primary purpose is to help with robotic operations and Earth observations, but it is bound to be the most coveted seat in the heavens for crew and visitors alike.
The next spacewalk is scheduled for Sunday bright and early, or rather just early for most of us because it starts around 6 a.m. Eastern time. All the action will be over by lunchtime at 12:38 p.m. The main task is to move the port 6 (P6) solar array from atop the Z1 truss (which is above Unity) to the port side where it belongs.
Monday will be the handoff of this P6 array from the station arm to the shuttle arm and back again. Mission control does not want to leave the array on the shuttle arm too long in case some emergency would require the shuttle to depart. While it is out there, the shuttle will not be able to dump any excess water.
Tuesday is the third EVA that will see the re-deployment of the P6 array. The deployments must occur in daylight with the 2B section going out first followed by the 4B section. This should be some tricky and tedious work by the spacewalkers with lots of umbilicals to mate and equipment to unlatch and unlock and deploy. The most visually stunning part of the spacewalk, the first unfurling of the golden array, is scheduled for 1:28 p.m. Set your online reminders!
On Halloween Wednesday, the crew will be trick or treating, hauling bags of goodies from the shuttle to the station. I suspect the station will get the treats, and the shuttle the tricks (soiled clothes, broken equipment, ugh—what did they do to deserve that?!). Astronaut costumes are highly anticipated.
Thursday is the fourth spacewalk. You’ll have to either stay up all night or get up really early to catch this one, especially if you live on the west coast. It starts at 4:28 a.m. and ends at 9:13.
Amazingly, there will a fifth and final EVA the very next day, on Friday. The reason they can be back-to-back is that this spacewalk is by a fresh crew, Peggy Whitson and Yuri Malenchenko.
The final hatch closing will be on Saturday, the undocking on Sunday, with landing in the dark at Kennedy on Tuesday, November 6 at 4:50 a.m. If you live on the flight path, you might alert your kids to expect some sonic booms. Tell them it is not the sound of angels bowling in heaven, but the Earth welcoming home 7 astronauts after a job well done.
Posted by m_dyson at 05:56 PM
October 24, 2007
Women in Charge
When I was growing up, there were no women astronauts or flight controllers. But I knew that would not always be the case. Russian Valentina Tereshkova had flown in 1963, and Star Trek’s Nichelle Nichols seemed at home on the bridge of the Starship Enterprise. So, like Heinlein’s Starman Jones who was denied the chance to train for astrogator, but because of his knowledge, was ready to do the job when finally offered, I studied physics and astronomy and watched for an opportunity.
That opportunity came in 1978 when NASA hired the first women astronauts and also opened other positions to women. I was fortunate to be hired and become one of the first ten women flight controllers. I cheered as Sally Ride made her first flight in 1983, and Judy Resnick became the second American woman in space in 1984. Women made strides in all areas of NASA, with Linda Ham becoming the first woman flight director in 1991.
It wasn’t until 1999 that a woman, Eileen Collins, commanded a shuttle mission. This week, Pam Melroy became the second. It was only last Friday, October 19, when another woman, Peggy Whitson, was put in command of a space station.
On Thursday morning at 10:33 Eastern time, the hatch between the shuttle and ISS will be opened, and the two female commanders will greet each other. Also on board Discovery is Stephanie Wilson, who became the second black woman to fly in space during her flight in 2006 (Mae Jemison flew in 1992).
So finally, the women are in charge!
Thanks to these trailblazing women, the thousand 5th-8th-grade girls signed up for the Sally Ride Festival this Saturday here in Houston will know that a career in space is a valid choice for them. These girls have the added benefit of meeting Eileen Collins who is the featured speaker. I am excited to be one of the 40 women recruited to run science workshops for these future scientists and explorers. I’ll be talking to them about their future on the Moon.
I hope that by the time these girls reach adulthood, women being in any position in space will no longer be news. It will be expected, normal, like women doctors and lawyers and accountants. Currently, only about 20 percent of the astronaut corps is female. Considering the almost total lack of women cosmonauts and that half of space crews are Russian, it will be many years before we see equal numbers of men and women in space. For space settlement to become a reality, this must change.
Space needs more women!
I’ve been told that the reason only 20 percent of astronaut classes are female is that not many women apply. The number of women getting degrees in science is on the rise, but the number of graduates in engineering, both male and female, remains low. The U.S. managed just 70,000 engineering graduates in 2006, far behind China’s 500,000 or the 200,000 produced by India. Can more attention to space make a difference? Absolutely!
It is easy to get discouraged pursuing an A in a math class or a degree in engineering without the constant reminder of the reward for the effort. Young people therefore need to hear others say how important space exploration is to the future, and how exciting, fascinating, and financially rewarding it can be to have a career as a scientist or engineer. Members of the National Space Society are helping fill this important need through conferences, educational outreach, scholarships, and simply by being friends and mentors who share an interest and contacts in the space movement. Young people who take advantage of these opportunities today will improve their chances of obtaining the education, skills and experience necessary to one day rule a space settlement.
See you there, ladies!
Former NASA flight controller
Posted by m_dyson at 11:24 AM
October 23, 2007
Harmony in Space
Heads up! The Space Shuttle Discovery is on schedule to launch at 11:38 a.m. Eastern time, Tuesday October 23. Inside the payload bay is a new “room” for the International Space Station. This important connector will mount to the Destiny lab and provide attach points for the European Columbus module and the Japanese Kibo module.
The bus-sized new piece used to go by the mundane name of Node 2. But the students of Brigette Berry’s 8th grade class at League City Intermediate School in League City, Texas, and Bradley Neu’s 9th grade science class at Lubbock High School in Lubbock, Texas, won a NASA contest with the name Harmony. These students will be at Kennedy Space Center to view the launch of STS-120, the 23rd shuttle mission to the International Space Station.
Commanding the flight is Col. Pamela A. Melroy (USAF, ret.). Melroy is the second woman to command a shuttle. Marine Corps Col. George D. Zamka is the pilot. The mission specialists are Scott E. Parazynski, Army Col. Douglas H. Wheelock, Stephanie D. Wilson, and Paolo A. Nespoli, a European Space Agency astronaut from Italy—where Harmony was built. Zamka, Wheelock and Nespoli are making their first spaceflights.
Also onboard is Daniel Tani who will replace Expedition 15/16 Flight Engineer Clayton Anderson. Tani will return on shuttle mission STS-122.
This 14-day flight will feature five spacewalks. Parazynski, a physician trained in emergency medicine, is the chief spacewalker. He has already been in space four times and made 3 spacewalks. Joining him outside will be Douglas Wheelock, a pilot with a masters’ degree in aerospace engineering. Besides the installation of Harmony, they will be removing the P6 solar array from atop the Z1 truss (at the center of the truss) and moving it to its portside home. Considering how much trouble previous crews had getting this oldest of the arrays to fold up, it will be interesting to see if this crew can get it moved and back out of its box.
For the latest news on this flight, visit http://www.nasa.gov/mission_pages/shuttle/main/index.html.
Posted by george_whitesides at 03:07 AM