Tektite I is a multiagency and industry program jointly sponsored by the Office of Naval Research, the National Aeronautics and Space Administration, and the Department of Interior, with participation by the U. S. Coast Guard. The prime contractor is the General Electric Co., which furnished the undersea habitat and assisted in program planning and scientific mission coordination.
On February 15, 1969, four U. S. Department of Interior scientists descended to the ocean floor in Great Lameshur Bay in the U. S. Virgin Islands and occupied the habitat. By March 18, 1969, the four aquanauts had established a new world's record for saturated diving by a single team. On April 15, 1969, the aquanaut team returned to the surface with over 58 days of marine scientific studies; this is nearly double the previous saturation diving record.
General Electric Co. engineering developed the underwater habitat with the emphasis on simplicity of design for living, operations, and maintenance. Food preparation, appliances, cooking, and cleanup were expected to require minimum time, so that the aquanauts could apply more time to the scientific mission. The scientific mission involved in situ studies of undisturbed fish, lobsters, and other biologic and geologic specimens in Lameshur Bay. (Perhaps the tempting sight of fish and lobsters swimming by changed the crew's "psychological needs" for food, but that is the latter part of this sea story. ) An overall description of the scientific mission and habitat will give a picture of the program, the system, and the constraints on food.
Tektite I was man's first, long-term scientific mission into the sea. Almost every aquanaut activity had scientific significance, from the analysis of sleep to zooplankton distribution studies. The scientific mission categories were marine biology, marine geology, biomedical evaluations, and behavioral studies of an isolated group of men under stress. Stresses included unknown hazards of long-term saturation diving as well as the sharks and barracuda. The numerous similarities between the hydrospace and aerospace programs may be summarized by stating that in both the crews must take their environment along.
The habitat consists of two, interconnected, 18-ft-high cylinders installed on a base section. Each cylinder is 12 1/2 ft in diameter and is divided into upper and lower compartments. All compartments have 2-ft-diameter plexiglas observation ports. Atop one cylinder is an observation cupola for additional scientific observation of underwater life.
 The Surface Control Center supplies 11.6 CFH of air to the habitat, which maintains the oxygen level at 160 mm partial pressure. This exchange of air is 0.34 percent of the total volume. One can consider the habitat a 99.66 percent closed atmosphere. Carbon dioxide (CO2) is scrubbed with baralyme. That sea-water pressure in the main hatch is equaled by the 2 1/4-times-normal atmospheric pressure of the habitat, permits this hatch to remain open throughout the mission.
Aquanauts enter the habitat by opening the shark cage door, swimming through the base tunnel, and climbing a ladder through the main hatch into the wet room. Scuba equipment and wet suits are removed, rinsed, and stored in closets. As cleanliness and dryness are very important to health, a shower, hair dryer, and clothes dryer are put to constant use. Wet and dry laboratories permit dissection, preparation, and examination of specimens. The water, air pressure, communications, and electric umbilicals from the Surface Control Center enter the wet room near the ladder of the engine room.
Upon climbing the ladder into the engine room, one sees the large Environmental Control System in the center. It contains heat-exchanging, dehumidifying, filtering, and CO2 scrubbing systems. The electric power system and controls, a large food freezer, a wash basin, a toilet, and a hot-water heater are installed along the room's perimeter. The interconnecting tunnel leads to the bridge.
The bridge provides for station monitoring, communications, and scientific equipment. A NASA atmospheric analyzer continuously monitors nitrogen, oxygen, water-vapor, and CO2 partial pressures. Portable backup atmosphere monitors are used to check trace gases such as carbon monoxide (CO) and acrolein. A master communications panel interconnects each habitat compartment, the Surface Control Center, and way stations in the surrounding water. Additional communications systems include open microphones, a sound-powered phone, and a regular phone for talking to surface personnel. A dual television display is used to monitor crew activities in each compartment and nearby underwater areas.
Down the ladder from the bridge are the crew quarters. This section contains four bunks, refrigerator-freezer and oven-stove combinations, and a counter with a built-in sink. Radio and television provide evening entertainment while the crew sit on folding chairs and eat dinner at a fold-away table. Underneath the rug is an emergency hatch which permits the crew to escape to nearby way stations with emergency air bottles.
Crew participation began early in the program when the research team concept was developed "to encourage team effort and spirit with the single purpose of a successful mission" (ref. 1). Initially, this concept was designed so that the crew could contribute to all phases of mission planning and operations. However, interest spread and all the engineers were soon deeply involved in developing Tektite on schedule. The time between proposal submittal and the start of the operational mission was 14 1/2 months.
Food equipment originally consisted of a combination "Griddle and Pressure Cooking Fixture" developed for torpedo boats during World War II. The freezer stored 16 cu ft of food and there was an additional 2.2 cu ft of frozen food stored in the combination refrigerator-freezer.
Since the habitat environment was approximately a 99.66 percent closed atmosphere with limited scrubbing and filtering capability, cooking was limited initially to heating food, pressure cooking, occasional baking, and broiling precooked meats. Pressure cooking was eliminated during a test session called the "live-in. " The cooking fixture was too complicated and all cooking would be under pressure in the regular mission regardless of the cooking vessel in use. Frying food represented a primary source of contaminants. In the frying process, animal fats were broken down into CO and acrolein.
Early in the closed-atmosphere studies by the General Electric Co., CO was found to appear and slowly increase in a two-gas spacecraft simulator. Detailed investigations found that small amounts of CO were continuously produced in the body and exhaled (ref. 2). Sjostrand demonstrated that it occurs through the breakdown in hemoglobin (ref. 3). Man exhales about 10 cc of CO per day. If the oxygen content is lower than normal, and the CO2 content increased, the formation of CO is increased (ref. 4).
The four aquanauts could produce 40 cc of CO per day. Theoretically, on the basis of human-produced CO alone, the Air Force safety limit of 25 ppm for continuous occupancy would be reached on the 60th day. Actually, the CO level stabilized early at 20 ppm and remained there throughout the mission. The 0.34 percent hourly change in the habitat atmosphere was given as the probable reason that CO did not build up and pass safety limits.
The menu was developed through a series of iterations beginning with a 5-day repeating menu. As expected, the aquanauts complained of no variety and the vegetables were evaluated as 'dike occasionally. "
An Air Force "food for space travel" report (ref. 5) had a 30-day mission menu that was distributed to the crew for comment. The crew commented, "This is more like it, but couldn't we have chili, enchaladas, tacos and tamales ?" Two members had started Sealab III training and had heard that previous Sealab crews lost their sense of taste during the mission. Their theory was that spicy food would help prevent everything from having a bland taste. These spicy foods were assigned to snack provisioning, since it was too late to obtain accurate caloric contents. An additional request was that 25 percent of all main meals be frozen TV dinners because 3 hours of swimming would make the crew too tired to prepare meals.
Final revisions to this menu occurred during the 3-day training period in December. Fresh eggs were requested, but no one knew if they could survive rapid pressure changes. At least one meal each week would be fully prepared by the crew, and would include muffins,  biscuits, or layer cakes. Again no one knew whether standard batter would rise properly in the oven. Following this meeting, one food company searched the literature and found that baking under higher atmospheric pressures had never been reported. They recommended adding baking powder to the next batter if the first cake did not rise properly.
Two pamphlets, "Basic Facts in Frozen Food Preparation" and "Basic Food Concepts," were developed and included in the training manual. Basic food concepts were emphasized to assure that proper nutrition was understood and applied to underwater diving. (For example, eating carbohydrates with animal protein prevents the liver from rendering animal protein unless for body growth and maintenance. ) This led to discussions of how to keep warm while immersed in cool water for several hours. Sugar and carbohydrates were not the answer. The U. S. Navy diving manual (ref. 6) warns that hyperglycemia could occur by eating too many starches and sweets and thus causing an excess of insulin. Eating protein foods like meat beforehand will provide a longer and steadier supply of dextros and also provide extra heat through animal protein digestion.
On the basis of a maximum swimming rate of 1 mile/hr, the aquanauts would expend 360 calories. One thousand additional calories in snacks were considered sufficient as the crew would neither be continuously swimming nor be in the water for more than 3 hours daily. The minimum of water temperature of 80° F was not considered an important caloric factor since the crew wore wet suits.
Since frying was not permitted, all fried foods were purchased frozen ready to eat. Frozen-food priorities were also given to veal, steak, and TV dinners. Although food priorities were supposed to be complete before the mission started, several food items were missing, including dozens of fresh eggs, 48 TV breakfasts, 9 half-gallons of ice cream, and 24 pounds of hamburger, cake, and bread. This resulted in an interesting change that started toward the end of the first week of the mission as described in the following anecdotes:
Preliminary reports from the crew indicate that eating turned out to be their ma)or entertainment. Pre-prepared meals were poor. Individually prepared meals were good. There were intermittent annoyances with the refrigerator and stove. We do not know presently whether these annoyances were failures or a function of the high atmospheric pressure in baking.
If Tektite were to be designed over again, the following changes would be made
In addition to these changes, for the future, consider the following questions:
Future interplanetary spacecraft and orbiting space stations are expected to be large enough for the crew to have canned foods for many meals. Tektite started in this direction, but the challenge is to provide technical advances, training, recipes, and menus to make basic canned foods and frozen foods into delicious dinners in closed atmospheres.
1. Miller, Gerald Tektite Crew Compatibility and Cohesiveness. Gen. Elec. Co. Memo, May 15, 1968.
2. Schaefer, K. E. Gaseous Requirements in Manned Space Flight, Bioastronautics. The Macmillan Co., (New York), 1964.
3. Sjostrand, T. The Formation of Carbon Monoxide by the Decomposition of Hemoglobin (in Vivo). Acta Physiol. Scandinav., Vol. 26, No. 338, 1952.
4. Clemson, C.J. Toxicological Aspects of Sealed Cabin Atmospheres of Space Vehicles. Astronautik 1, vol. 4, no. 133, p. 159.
5. Taylor, A.A.; Finkelstein, B.; and Hayes, R.E.: Food for Space Travel: An Examination of Current Capabilities and Future Needs. ARDC-TR-60-8, Andrews AFB (Washington, D. C.), July, 1960.
6. Anon.: U. S. Navy Diving Manual. Pt. 1, Navships Rept. 250-538, 1963.