20 Minutes With Capt. Heidemarie Stefanyshyn-Piper
Thomas T. Astrene, Publisher | TLT 20 Minutes October 2015
This mechanical engineer turned astronaut lubricated a balky mechanism on the International Space Station—while spacewalking 250 miles above Earth.
HEIDEMARIE STEFANYSHYN-PIPER - The Quick File
Capt. (Ret.) Heidemarie M. Stefanyshyn-Piper was born and raised in St. Paul, Minn. She attended the Massachusetts Institute of Technology on a Navy ROTC Scholarship where she earned a bachelor’s of science degree in mechanical engineering in 1984 and a master’s of science degree in mechanical engineering in 1985.
As a Navy Engineering Duty Officer, Capt. Piper served at ship repair facilities, including Pearl Harbor Naval Shipyard and Shore Intermediate Maintenance Activity Pearl Harbor. She served on the maintenance staff at Commander Naval Surface Force, U.S. Atlantic Fleet and at the Naval Sea Systems Command. She received the VADM C.R. Bryan Award from the Engineering Duty Officer School Basic Course and qualified as a Surface Warfare Officer on board the USS Grapple.
Capt. Piper also is an experienced diving and salvage officer. Among her major salvage projects is the development of a salvage plan for the Peruvian Navy salvage of the Peruvian submarine Pacocha.
Selected as an astronaut by NASA in 1996, Capt. Piper reported to the Johnson Space Center in Houston. She is a veteran of two space flights: STS-115 on the space shuttle Atlantis in September 2006 and STS-126 on the space shuttle Endeavour in November 2008. She has logged more than 27 days and 15 hours in space, including five space walks totaling 33 hours and 42 minutes of Extra-Vehicular Activity time.
Capt. Piper retired from her most recent Navy assignment, commanding officer, Southwest Regional Maintenance Center, in March. Her personal decorations include: Defense Superior Service Medal, Legion of Merit (four awards), NASA Space Flight Medal (two awards) and NASA Exceptional Service Medal and other personal and unit awards.
In May she addressed STLE members as the keynote speaker at the society’s 2015 Annual Meeting & Exhibition in Dallas. In June STLE’s board voted to make her an Honorary Member, which recognizes “exceptional achievements in science and unusually important service to the society.” She is one of the few who have received the honor without being an STLE president.
Capt. (Ret.) Heidemarie Stefanyshyn-Piper
TLT: You were a distinguished Navy officer with an excellent service record. What made you want to become an astronaut?
HMSP: I had decided to apply to the astronaut program because I have always had a desire to fly. I still remember my first airplane flight as a four year old traveling to Germany. But at that time, the only career for women in the aviation industry was as a stewardess, as flight attendants were known back then. That option did not really appeal to me, so I concentrated on math and science and decided to pursue mechanical engineering.
I applied for and received an ROTC Scholarship from the Navy to pay for college. After my freshman year in college, my plan was to go to Navy Flight School and become a pilot. Unfortunately, on my pre-commissioning physical I failed the eye test to become a pilot. So I decided to become a Navy Diver and Engineering Duty Officer instead.
My initial tours in the Navy were in ship repair. I also participated in several salvage projects. It was at that time that I learned about NASA and the Astronaut Program. The minimum requirements to apply for the Astronaut Program are a bachelor’s degree in engineering, science or mathematics; at least three years related professional experience; and passing the NASA space flight physical. Since I met and exceeded the minimum requirements, I decided to apply to the program.
I thought I had a lot to offer to the Space Program: distinguished naval officer, a master’s degree in mechanical engineering from MIT, qualified salvage officer, fluency in German and Ukrainian and experience in underwater ship repair. I had to apply to the program twice before I was selected. I later learned that few astronauts are selected on their first application, and most apply numerous times prior to their selection.
I knew the competition to be selected as an astronaut would be very tight. NASA selects fewer than 1% of qualified applicants. All of the astronauts excelled in their previous careers, otherwise they would not have been competitive in the astronaut selection.
TLT: What was the process that resulted in you being selected by NASA to be an astronaut?
HMSP: The process to be selected as an astronaut is very lengthy. Almost two years prior to a new astronaut class reporting to Johnson Space Center (JSC) for training, NASA opens the job announcement on USAJOBS (the federal government’s source for federal government job listings, including astronauts). Active-duty military members are required to apply through their services, and each service sends applications to NASA. Civilian applicants apply directly on USAJOBS.
I applied to the Navy board, and my name appeared on the list of qualified applicants sent to NASA. NASA reviews all applications to determine which of the “qualified” applications—those meeting the minimum requirements—are “highly qualified” applicants. NASA then sends a Qualifications Inquiry Form to the supervisors and references of the highly qualified applicants. My supervisor let me know that he received a form from NASA, so I knew that I was still being considered as an astronaut candidate. NASA then reviews the highly qualified applications to determine interviewees.
By this point the process is a year out from the class reporting to JSC. As a note, the first time I applied, I was considered highly qualified (my supervisor received the inquiry form), but I was not selected as an interviewee. During my second application, I did receive a phone call to come to Johnson Space Center for a week that consisted of the formal interview, an in-depth medical evaluation and an orientation. NASA invites 20 interviewees at a time and typically will have five weeks of interviews. Today, with additional requirements for longer space flight (six months in orbit), NASA does another screening of finalists who return to JSC for additional medical tests.
At the end of the lengthy process, selected astronaut candidates receive a phone call from the head of the Astronaut Office that they have been selected as an astronaut candidate to report in August to begin training.
I still remember receiving my phone call. I was getting ready to leave the office to take my semiannual physical fitness test. I was the last one to show up for the test, but when I gave my explanation, everyone said I had a good excuse.
TLT: Describe the two flights and missions you participated in.
HMSP: STS-115 resumed construction of the International Space Station after the Space Shuttle Columbia accident on Feb. 1, 2003. Our crew of six astronauts launched on Sept. 9, 2006, aboard the Space Shuttle Atlantis to deliver and install the 17.5-ton P3/P4 truss segment to the port side of the external on the International Space Station.
The truss included a new set of photovoltaic solar arrays, which provide additional power for the space station. The truss also contains the Solar Alpha Rotary Joint (SARJ), which rotates 360 degrees to position the solar arrays to track the sun for power generation.
Three spacewalks, of which I conducted two of the three, were required to put the P3/P4 truss into service. During the space walks astronauts connected power cables and activated the required gear to activate the P3/P4 truss. The mission landed at Kennedy Space Station on Sept. 21, 2006, after nearly 12 days in orbit, including six days docked to the International Space Station.
STS-126 had two main missions. The first was to deliver equipment and supplies to the International Space Station. The second was to service and repair the starboard SARJ. The flight launched on the Space Shuttle Endeavour on Nov. 14, 2008, and docked to the space station two days later. The shuttle carried a reusable logistics module, which delivered more than 14,000 pounds of supplies and equipment, including key life support and habitability systems needed to increase the space station crew size from three astronauts to six. The logistics module returned nearly 4,000 pounds of equipment and scientific samples from station research back to earth.
The crew also conducted four space walks to service the starboard SARJ and lubricated both the starboard and port SARJs. The starboard SARJ had been limited in its operations due to increased current draw and high vibrations detected three months after it was placed in service. The Space Shuttle Endeavour landed at Edwards Air Force Base on Nov. 30, 2008.
Capt. Piper working on the Solar Alpha Rotary Joint on the International Space Station approximately 200 nautical miles above Earth.
TLT: Specifically, what was the problem with the SARJ, and what repair did you effect?
HMSP: The Solar Alpha Rotary Joint (SARJ) is a single-axis pointing mechanism used to orient the solar power generating arrays relative to the sun for the International Space Station. Approximately 83 days after its on-orbit installation, the starboard SARJ mechanism aboard began to exhibit high drive motor current draw. Increased structural vibrations near the joint also were observed.
After two months of investigation to determine the likely cause of the anomalous signatures, an inspection of the mechanism during a spacewalk showed that the bearing race ring was damaged and covered in debris. The outer nitrided layer of the SARJ race ring had spalled from the base 15-5 PH steel material. The NASA-Industry team concluded that the most probable cause of the damage was a lack of adequate lubrication between the trundle bearings and the race ring surface (
1). The lack of lubrication led to excessive friction, which caused tipping of the rollers and stress on the race ring.
Due to the operational impacts of restricting the movement of the starboard SARJ, a recovery plan was necessary to restore the starboard SARJ. The SARJ Recovery Team concluded that required actions were to remove as much debris as possible from the damaged race ring and to add grease lubricant to all three bearing surfaces of the race ring.
Debris removal was intended to decrease drive motor currents and improve torque margin. The intent of the lubricant was to maintain a coefficient of friction below the critical roller tipping value and to protect the remaining undamaged surfaces from experiencing degradation. Braycote 602EF© was chosen because the base oil has the lowest vapor pressure of all available space greases. It also has molybdenum disulfide, which is an excellent lubricant for sliding and capable of handling high loads.
The STS-126/ULF2 mission, scheduled for November 2008, was selected to clean and lubricate the damaged race ring. The recovery team also decided to remove and replace all 12 trundle-bearing assemblies (TBAs) during ULF2. A significant amount of debris had accumulated on the TBAs, so their replacement would result in additional removal of debris from the joint. This also allowed for the return of the original TBAs for inspection to assist in the root cause investigation.
Cleaning and lubrication trials showed that the best method to clean the SARJ was to wet the surface with an EVA wipe pre-lubricated with Braycote 602EF© and then scrape the surface with a scraper tool. Lubricating the surface prior to scraping proved to be the best method to contain the loose debris particles and prevent them from being liberated and dispersed throughout the rest of the mechanism while scraping. The final application of lubricant to the surfaces after cleaning was done using a grease gun.
A 60-degree section of race ring was used to determine the pattern and quantity of grease to be applied. Based on testing and crew input, it was decided that the best way to apply lubrication to the race ring was to place a single bead of grease down the middle of the roller track. The grease gun was a modified chalk gun developed for shuttle tile damage repair. The outer race ring and datum-A-surfaces were lubricated with a straight nozzle. The inner race ring surface is not visible to the crew, so a unique lubrication tool, called the J-Hook nozzle, was developed by the JSC EVA tool team to allow the crew to lubricate that surface. The J-Hook was designed so the grease would be smeared along the width of the race ring surface and would encompass the roller track of the TBA and DLA rollers. The final grease configuration required residual grease dams on either side of the roller track after the TBA roller had passed over and spread the grease. These repositories of grease on the sides of the track serve as a source of oil that will constantly re-wet the roller track and provide lubrication during subsequent SARJ operations.
Lab tests also were run to determine the impact of grease added to a race ring surface contaminated with metallic particles, assuming that not all particles were captured during the cleaning process. These tests showed that the hydrodynamic force generated by the roller passing over the grease was enough to push a majority of the debris out of the roller track. As a result, the addition of lubricant to the damaged race ring serves a dual purpose as a cleaning fluid for any debris left on the SARJ after the cleaning operation. The clean and lubrication operations were successfully completed during ULF2.
As noted earlier, anomalous structural vibrations were one of the first hints of a problem with the SARJ. The surface of the race ring had degraded significantly, and it was not anticipated that the clean and lubrication tasks would have a significant impact on the vibrations observed on ISS. The accelerometer data after ULF2 showed that the peak accelerations due to SARJ rotation had in fact been reduced significantly from the pre-ULF2 accelerometer data.
End of J-Hook after a spacewalk showing the grease oozing out and voids within grease.
TLT: What does it feel like to spacewalk? How did you train? Can anything really prepare you for the experience?
HMSP: Being out on a spacewalk is an amazing experience. I remember my first spacewalk on STS-115. It was during a night pass when my partner, Joe Tanner, and I exited the space station airlock. I felt very comfortable. Having a diving background, it felt like being on a night dive. It was dark, but with helmet lights you could see 4-6 feet around you.
Compared to our training, it was much easier to move around. Our training is conducted underwater in the Neutral Buoyancy Laboratory, a 100-feet wide by 200-feet long by 40-feet deep training tank. In the water, crewmembers are weighed out to be neutrally buoyant, so you neither sink nor float. But you still have forces acting on you: gravity, buoyancy and the water resistance. In space, you have none of these, so you move much more easily, but you never want to move too fast. You always want to maintain control of yourself so that you do not damage any equipment or become detached from the space station.
I always found that when you concentrated on the tasks at hand, it felt very much like being back in training. Our training is very good in preparing you to accomplish the tasks, but it is up to the individual to not be distracted by the surroundings. I found it best not to dwell on the fact that I was out in free space, orbiting the earth and just complete the mission. But when I did have a free moment or two, it was incredible to look around and marvel at where I was at. I could look down and see the earth going by. The planet is very blue (70% of the earth is covered by water) and very white (clouds). I had always thought I was very good at geography, but it was much harder to recognize what part of the earth we were flying over than I thought it would be.
I also was amazed at looking at the horizon. The orbit of the space station is about 200 nautical miles, which is not high enough to see the earth as a complete ball, but high enough to see the curvature of the earth’s horizon. I recall looking at the horizon, seeing a thin blue layer (our atmosphere) and beyond that only the blackness of space. It makes you feel how fragile the earth is, but yet this amazing planet sustains life.
All of my spacewalks on both flights took me to the ends of the space station’s external truss. From that viewpoint, I could look back and see the space shuttle and the majority of the space station. It showed that we had built this incredible outpost in space and the amazing vehicle, the space shuttle, which could be launched into space, re-enter and then do it all over again.
Grease gun following use during a spacewalk.
TLT: Describe the lost tool bag episode.
HMSP: For our work on the SARJ, all of our tools that we took outside for our spacewalk were packed into a larger bag, including the new Trundle Bearing Assemblies, storage bags, EVA wipes, grease guns, scraper tools, etc. The smaller tools (EVA wipes, scrapers) were packed in a smaller tool bag, which we carried to the worksite. Everything inside the bag is tethered to the bag, so it doesn’t float away when the bag is opened.
About two hours into the spacewalk, I reached into the larger tool bag to take out the tools for my next task. To my surprise, there was some grease on my gloves. I checked the grease guns that were still in the bag, and all of them had their covers on and the flow nozzles in the off position. I could not easily find the source of grease, but every time I moved something, there was more loose grease, mostly small (an eighth inch diameter or smaller) pieces.
I decided that it would be best to clean the visible grease. I took out one of the spare EVA wipes and started wiping up grease. Since I expected that everything inside the larger bag was tethered, I just reached for an item, removed any visible grease, let it go and reached for the next item. When I let go of the tool bag, I could see out of the corner of my eye that it kept going. It was not tethered.
I did have a momentary thought to lunge for it, but I decided that would make things worse. I did not want to be bobbing at the end of my tether. The best thing to do was to notify Mission Control of what had happened and recover from the incident. We continued the rest of the EVA and the remaining three EVAs. We had plenty of grease onboard to complete the work on both the port and starboard SARJs. Without two grease guns, we had to share that tool. We relied on the pre-greased EVA wipes to clean the existing debris on the race ring, which proved to be a better method. The wipes had sufficient grease to capture the debris, and the grease was contained. After going back, we learned where we missed tethering the bag and made sure that we did not repeat the mistake.
TLT: Please give a good piece of advice for anyone planning on traveling in outer space.
HMSP: The best advice for traveling into space is to know and understand your tasks that you will be accomplishing in orbit. This includes planning for contingencies and then being prepared for the unanticipated. Nothing ever goes as planned in orbit, because it is nearly impossible to replicate the orbit environment on the ground.
REFERENCE
1.
Harik, Elliot, et al. (2010), “The International Space Station Solar Alpha Rotary Joint Anomaly Investigation,” NASA Technical Reports Server (NTRS). From
here.
You can reach Heidemarie Stefanyshyn-Piper at hmsp@me.com.