Orthopaedist acts as medical officer and proxy scientist during NASA mission

“The acceleration was incredible,” said Robert L. Satcher Jr., MD, PhD, describing the launch of the space shuttle Atlantis on Nov. 16, 2009. “It took less than 9 minutes to go from sitting on the launch pad to traveling 17, 500 miles per hour—faster than a bullet.”

The space shuttle broke the sound barrier, creating a visible shock wave, as 7.5 million pounds of thrust propelled it skyward. The launch, which began a 4.5 million-mile journey to the International Space Station and back to earth, was one of many unforgettable experiences that Dr. Satcher had as a National Aeronautics and Space Administration (NASA) space shuttle crew member. He recounted the details of the 11-day mission during the Opening Ceremony of the 2010 AAOS Annual Meeting in New Orleans.

Ready for lift off
After undergoing intense preparation at NASA’s Lyndon B. Johnson Space Center in Houston, Texas—including land and water survival training, flight training in a T-38 supersonic jet, and many hours in the pool at the space center’s Neutral Buoyancy Laboratory—Dr. Satcher was ready for the mission.

Although dense cloud cover threatened to delay the ship’s launch, the clouds dissipated in time and the ship was cleared for take off. Dr. Satcher and the other five crew members were pushed back in their seats as the powerful engines ignited and the ship raced toward outer space.

“Because the pressure is sustained, it feels as though you weigh between 2.5 to 3 times more than your normal body weight,” explained Dr. Satcher. “It’s as though there’s an elephant standing on your chest, which makes breathing difficult after a while.”

The mission included delivery of 30,000 pounds of supplies, installation of a high-pressure oxygen tank, and repairs to the space station’s robotic arms.

“We converted the inside of the shuttle from a launch vehicle into a place where we would live for the next 2 weeks,” said Dr. Satcher. The astronauts rearranged the mid-deck, set up computers and other communications equipment, and inspected the outer surfaces of the vehicle.

“We also had to get all the other systems running, including the bathroom and the kitchen,” he said.

By the time the ship reached orbit, the space station was somewhere over Europe.

“It took us 3 days to catch up with the space station because we were at a lower orbit, meaning that we were going around the earth a little bit faster than it was,” he said.

When Atlantis neared the space station, said Dr. Satcher, “we fired our rocket engines to boost the ship up.”

Dr. Satcher was impressed by the space station, which is as long as a football field.

“It took millions of engineering and man hours to put it together piece by piece, and it was brought up piece by piece,” he said. “It was a truly amazing sight.”

Stepping out into the abyss
One of the most memorable parts of the mission came when Dr. Satcher performed his first space walk, or extra-vehicular activity (EVA). Preparing for each space walk takes 12 hours.

“Nitrogen needs to be purged from your bloodstream,” explained Dr. Satcher. “We do that by depressurizing the airlock and raising the concentration of oxygen in the airlock atmosphere. Then, we put on masks and breathe pure oxygen for several hours to make sure that nitrogen doesn’t create bubbles in the bloodstream.”

Finally, Dr. Satcher and another crew member stepped out of the space ship and into outer space to repair the station’s robotic arms.

“Prior to the mission, I spoke with a lot of people who had done EVAs to get some perspective, but there’s no way anyone can really describe it,” he said.

“It was the most spectacular view I’ve ever seen,” he continued. “When I came out of the hatch, I stared at the view of the earth for as long as the timeline would allow, painting a mental picture. The earth stood out in stark contrast to outer space, which is an incredibly dark black. The absence of light goes on forever.”

The repair of the robotic arm, which took 3 hours, went smoothly.

“Using all the instruments reminded me a lot of performing surgery,” he said.

Dr. Satcher completed another space walk several days later to install a 1,200-pound high-pressure oxygen tank to supply breathable air to the space station.

“Because everything is weightless in space,” he said, “it only took two people to move the tank around.”

Space experiments
As a proxy scientist, Dr. Satcher helped conduct several experiments during the mission. One experiment involved evaluating how disk height changes in space. Dr. Satcher noted that most people gain 1 to 2 inches of height in space.

“NASA is interested in many ergonomic issues,” he said. “There is a plan to build a ‘next generation’ space ship, and I think much of that data will be used for that.”

Other experiments included studies that evaluated how going into space affects the immune system and sleep patterns.

“We also did an experiment with transgenic mice that grew from pups to adults in orbit,” he said. “The mice were overexpressing one of the osteogenic proteins. We investigated the ways in which growing up in a weightless environment may have affected their skeletons.”

Readjusting to life on earth
After spending 7 days at the International Space Station, the crew began the journey back to earth. The space shuttle had a picture-perfect landing at NASA’s Kennedy Space Center on Friday, Nov. 27.

“The mission went by way too fast,” said Dr. Satcher. “I wish I could have stayed there longer.”

Reacclimating to gravity was fairly easy; his sense of balance was affected for a few days, but it quickly returned to normal.

“My legs and arms definitely felt heavy for a few hours after I got back,” he said.

He noted that the body adjusts to a lower intravascular volume in space, which results in some deconditioning of the cardiovascular system. Before astronauts return to the earth, they engage in ‘fluid loading’ to re-establish the intra-vascular volume.

“Because the autonomic nervous system has to readjust, some people faint after landing, or at least become light-headed. All the fluid goes down to the legs and the body isn’t pumping it back up into the head the way it usually does. Fortunately, nobody on our crew had that problem.”

Dr. Satcher hopes to have another opportunity to go to outer space on a NASA mission.“We’ve just begun to take a few baby steps in exploring our solar system,” he said. “We’ve been to the moon, and our next target is Mars and beyond.”

Jennie McKee is a staff writer for AAOS Now. She can be reached at mckee@aaos.org

Space tweets
Dr. Satcher used Twitter, the social media tool, to send out short messages, or “tweets,” about his experiences before, during, and after the space mission.

“I tweeted as ZeroG_MD about the medical aspects of adjusting to life in outer space,” he said. “Under the name of Astro_Bones, I gave general commentary on random things of interest, such as my view of the earth or what the crew members had for dinner.”

A sampling of Dr. Satcher’s tweets follow:

• Launch was amazing! 7.7 million pounds of thrust, mach 25, microgravity in less than 9 minutes! Awesome.
  7:02 a.m. on Nov. 18, 2009
• Spacewalks are complete. Was fantastic experience. Can’t wait to share photos. Houston looked great from 210 miles.
  8:14 a.m. on Nov. 24, 2009
• Just closed the hatch to the International Space Station. Had a great time on station. Tearful goodbyes—seems like we just arrived. . .
  12:36 p.m. on Nov. 24, 2009

Follow Dr. Satcher on Twitter: Astro_Bones and/or ZeroG_MD