In a nondescript building on a corner of Arizona State University’s Polytechnic campus sits a pair of gray metal boxes that look like souped-up shipping containers. They’re actually elaborate pieces of equipment belonging to the Aviation Program, but there’s more to it than that: These things go back to the days when men in silver suits skidded across space in cans.
Used by two Mercury Seven astronauts, U-2 spy pilots, the world-record parachutist who jumped from the edge of space and recently the SpaceX program, the heavy-duty altitude chambers simulate extreme conditions and help save lives.
This year is the Aviation Program’s 20th anniversary. It lucked out the day ASU acquired the former Williams Air Force Base, since it came with the chambers that students now have access to each semester. ASU has two altitude chambers: one for training and another for research. The research chamber is one of only three chambers in the country available to civilians.
“No other aeronautical university — whether it’s the University of North Dakota or Embry-Riddle — can compete with the capabilities that we have here at Arizona State University,” said Ronald Diedrichs, aerospace physiologist and lecturer. Diedrichs operates the training chamber during sessions that could save a pilot’s life.
Hypoxia is a condition that affects pilots when they fly at high altitudes above 10,000 feet. “Insidious” is the word aviators often use to describe it. Typical symptoms are lightheadedness, euphoria, tingling in the extremities and unconsciousness. Losing cognitive control while flying an airplane ends in crashes.
“It’s amazing how many people lose consciousness ... and don’t live through it,” Diedrichs said. “It’s not advertised very much.”
Over the past 25 years, there have been 46 crashes involving or possibly involving hypoxia, according to the National Transportation Safety Board. Some were clearly caused by hypoxia. In others, there was no evidence beyond a pilot speaking with slurred speech and not obeying air traffic controllers’ commands before crashing.
In traditional aviation education, students learn about hypoxia, but not in a controlled environment where they can learn to recognize their personal symptoms.
“It’s that recognition of those subjective symptoms that can give early warning to a pilot that they need to lower their altitude or get supplemental oxygen,” said Marc O’Brien, aviation program director. “The training that they get here is better than they would get at an airline. The airlines don’t have these kinds of facilities.”
Diedrichs has flown 49 years safely. One memorable day flying over southern Colorado en route from Phoenix to a small city on the Kansas state line, the hypoxia training he received in the military kicked in.
“I’ve used the knowledge myself,” he said. “I looked down at my pulse oximeter that I always wear when I’m flying in an unpressurized airplane, and I saw I was really low on oxygen saturation. I immediately dialed my autopilot down to 11,500 feet — 1,000 feet per minute — hoping I would stay conscious. I did not expect that I would stay conscious. Everything worked, and I got down safely.”
Diedrichs is a professional pilot who is board-certified in aerospace physiology.
“My job No. 1 is to make sure it’s safe,” he said.
The first thing Diedrichs does during a training session is denitrogenate the chamber. About 80 percent of Earth’s atmosphere is nitrogen.
“If I take you to half an atmosphere, which is 18,000 feet, you would fizz, just like a soda would fizz,” he said. “It’s called decompression sickness.”
Subjects breath pure oxygen for at least 30 minutes before going to altitude. Instructors go into detail about how the oxygen equipment in the chamber works.
Once they’re at 25,000 feet, they take half the students off oxygen. The other half watches them while they undergo hypoxia.
“The objective is those that don’t have their masks on nail down in their minds what their symptoms are, because everyone gets different symptoms,” Diedrichs said. “They might not even go through the same symptoms, and that’s why the military has them go through the training every five years.”
They do an explosive decompression at 5,000 feet, like what you’d experience on an airliner if a window or door blew off. It’s an FAA-certified course.
The program charges per seat (at 16 seats) to use the main chamber, plus oxygen, per day. One session with a full crew, including an aerospace physiologist, two crew chiefs, an inside observer, driver and participants, can cost as much as $20,000.
“I’m trying to give them enough knowledge to fly for 50 years uneventfully and enjoy all of it,” Diedrichs said. “I call it life assurance training.”
The chamber has other applications besides flight, O’Brien pointed out. It’s a great research facility and resource for the private sector.
“We’ve had different clients come in; most recently, SpaceX has been in testing their space suits,” O’Brien said.
“We’ve had military come in for different things. We’ve had pharmaceutical companies to test things like insulin-delivery devices in a controlled environment. We can replicate the cabin-pressure altitudes of airliners, and also in situations with rapid or explosive decompression, so that these companies can test their devices and make sure they’re functional in all kinds of circumstances.”