|Test Subject page 3 of 3|
|This scan from the April 19, 1965, issue of Missiles and Rockets shows me in position to enter the box. All these photographs were taken during the “dry run” or practice of the procedure for the test. Closed circuit TV was used to monitor the test itself. A 16mm movie film was made from the videotape, but now, of course, it needs to be put back on video for easier viewing. By the way, this suit was not made for walking. It was made to conform to the couch in the Gemini spacecraft. Ed White was forced into this curved position when he made the first US space walk. Grissom and White and other astronauts trained in this chamber for the Gemini program once the EVA systems were ready and we had a Gemini spacecraft simulator installed. The article says: Extravehicular spacesuits identical to one just rushed through tests at NASA’s Manned Spacecraft Center in Houston will be worn by the GT-4 crew during the second manned Gemini mission in early June. Then in a later paragraph: MSC spokesmen said, however, that the first extravehicular activity “is scheduled for GT-5.” Of course, it did occur during the GT-4 mission. Management didn’t want to say that we had been trying for GT-4 in the event that preparation could not be made in time. The suit was the ‘pacing’ item. Micrometeoroid and thermal protective layers had to be integrated into the basic suit and tested before use in flight.|
|A view of the closed-circuit TV monitor in the instrumentation trailor during a Gemini EVA training test. We had installed 'Gemini Boilerplate 2' in the chamber in place of the thermal box that my test was conducted in. Many test subjects and astronuats worked through the Gemini EVA procedures in this facility. This is Ed White training for his EVA on GTS-4. Original image was on slide film. The moire pattern is the result of the 'interference' between the scanner lines and the TV monitor raster lines.|
|What I Felt as a Result of Exposure to the Test Conditions
Normal atmospheric pressure holds the air inside an open bottle and keeps a balloon from expanding too much from the pressure inside it. When normal pressure is removed, as by vacuum pumps reducing pressure in an airtight chamber or by venting the atmosphere of a spacecraft cabin in orbit, the air in the bottle will flow out and the balloon will burst (depending on its strength and ability to stretch). Various body cavities are filled with air and as the pressure around the body is decreased, that air has to flow out or it stretches body tissues to a painful condition. The lungs are open to the exterior of the body, so normal breathing will let the air out. The air in the middle ears normally comes out without much problem; yawning and swallowing will normally do. Those who have driven up mountains or have flown have experienced this although not to the same degree.
However, gas in the stomach and intestines may be difficult to relieve. Belching and flatulation (to use a modest term) will work for most people, but that was always difficult for me. So during depressurization, I would get severe ‘gas’ pains in my intestines. I managed to get some relief from it but it was distracting.
| The Cold Environment
The cold basically was not a problem. The only things that got cold were my feet and it felt like the cold of walking in snow with a good pair of boots on. The medical officer was concerned about the temperature of my toes and insisted that I keep moving my feet back and forth to warm them. The airflow in the helmet (this was not air actually, but 100% oxygen) was cool and comfortable. I did not notice any effect of the cold on my face. During the first 30 minutes with the visor that had the best thermal insulation, the inside surface temperatures were moderate. I had no problem reading the eye chart. There might have been some very slight fogging around the perimeter of the visor.
After the first test, the chamber pressure was increased to equal the airlock pressure (manlock) so that the lock observer could come in to assist me and so that it would be safe to remove the helmet for a brief moment. The lock observer helped me change helmets and reconnected the instrument cables. The chamber was depressed again after the lock observer had returned to the safety of the airlock. It was almost immediately obvious that the second visor material did not have the thermal insulation qualities of the first. The margins of the visor began to get foggy quickly. I think it felt colder too. However, at about 10 minutes the lock observer called out, “Test Subject, back out of the chamber!” The test conductor asked about the problem and the lock observor repeated that I should come out of the box. The test conductor then directed me to back out. As I stepped backwards it felt like I was walking on sticky gum. I sat down and the LO reported that he had seen some sort of vapor drifting across the floor of the box and down the ramp.
So the test was terminated. It turned out that the test team had observed temperatures on the inner surface of the visor approaching freezing anyway, so that would have required termination of the test.
| During Repressurization
All the air that left the body during depress had to get back in during repress. Again, just breathing takes care of the lungs and the stomach and intestines are limp so they just get a little flatter. However, those who fly or dive know that it can be difficult to get air back into the middle ear. Most people can yawn or flex the jaw and the Eustachian tube will open and allow air from the throat to flow into the middle ear. Sometimes it requires holding the nose and mouth shut and pressurizing the throat with chest pressure to force the tubes open. Of course you can’t hold your nose through the helmet visor. (The Shuttle helmet has an optional foam plastic block that can be used to block flow from the nose for this pressure technique.) My Eustachian tubes are unusually difficult to open, so pressure doesn’t equalize and outside pressure tries to get in through the eardrum. This is very painful of course. You may have seen slight cases of the in commercial air flights were the pressure goes from about 12 psia to 15 psia during landing. Just imagine going from about 4 psia to 15 psia! Actually, the test team has to stop repress and sometimes depress a little to let the test subject work the jaws or whatever can be done to get relief and then slowly continue repress. This is frustrating to the test team because they want to get the test subject back to safe conditions quickly and end the test.
The Source of the Vapor
Post-test investigation revealed that the thermocouple on the floor, which was supposed to sense the floor temperature and control the electrical floor heater, had come loose and was actually exposed to the cold of the box walls. This caused the heater to operate at maximum power and the floor then got hot enough to begin melting the yellow rubber overshoes. Fortunately, there was no air (thus no oxygen) to support combustion at vacuum.
| A few of the Steps we took to avoid similar problems in future tests:
1) Install a separate sensor to cut off the source of power at a safe maximum value.
2) Display the measurement to the appropriate test team member with a visual or aural warning.
3) Inspect the test systems carefully just prior to the test to verify that all are in order.
These, and others things that we learned as we continued, didn’t eliminate all problems, but in the 40 some years of testing in that facility there have been no serious injuries.
|PAGE ONE - NASA photos showing me in a Gemini space suit during preparations for a thermal-vacuum test of the helmet visor prior to GTS-4. The test, test objective and temperature instruments on the helmet are described.
PAGE TWO - NASA photos of the thermal compartment that sat inside a large vacuum chamber. A full view of the suit with a description of various suit components. A close-up view of the upper suit and helmet showing the thermal sensors on my nose and on the helmet.
PAGE THREE - A scan of the NASA photo of me that appeared in the April 19, 1965 issue of Missiles and Rockets. My photo of the closed-circuit television view of Ed White during his vacuum chamber training for GTS-4. The test results are summarized and I describe what being in a spacesuit at thermal-vacuum conditions was like for me.
SMEAT - The Skylab Medical Experiments Altitude Test
My photos of the 56-day vacuum test with Bob Crippen, Karol Bobko, and Dr. Bill Thornton. Features Jessica Savitch on the news team that reported the chamber entry and presidential candidate George McGovern, who visited during the test.
First US Woman EVA - My experience with Kathy Sullivan's training for this major event in space exploration history.
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