[57] Most of you are probably familiar with the Apollo Applications Program (AAP), the NASA mission which will succeed Apollo. The Apollo Applications concept has had a long history. However, it is only recently that its configuration has been more or less solidified.
The AAP is based largely upon the use of currently available hardware. A three-man space station will be assembled in orbit about 200 n. mi. above the Earth. This space station, or orbital assembly, will consist of a command and service module, a multiple docking adapter, and an orbital workshop. The orbital workshop is the true essence of AAP. It is actually the spent hydrogen fuel tank of the second stage, or SIVB stage, of the Saturn [B rocket.
Three AAP missions will be flown over a period of about 9 months. The first mission will be 28 days long and the other two will each be 56 days. The second 56-day mission will have an Apollo telescope mount added to the orbital assembly. All missions will employ the same SIVB tank, which will be left in orbit in a deactivated state between missions. The first two AAP flights are primarily medical missions, whereas the third has an astronomy objective.
The food system to be used on AAP will be substantially different from that used on Mercury, Gemini, Apollo, or MOL. This does not stem from a desire on our part to make things different simply for the sake of flying a novel system; in reality there is substantial pressure to utilize existing Apollo hardware, wherever practicable. The requirement that the AAP feeding system be different stems from two major factors: (1) Some flight foods used in the past are not satisfactory from a number of standpoints so there is a pressing requirement to achieve a better system, and (2) the requirements imposed upon the flight feeding system by the AAP mission profile are much more stringent than the requirements placed upon any previous flight feeding system. This is not because of more rigorous conditions, for indeed storage conditions will be better, but is rather because of a need to make a food system as good as a good conventional food source, yet also to allow for the conducting of a medical experiment.
The feeding system will be one which will meet a set of requirements which we consider reasonable in the light of the objectives of the AAP missions as well as of the constraints that the spacecraft will impose upon the foods and packages.
Two primary objectives of the AAP missions profoundly influence the design of the feeding system. First, there is an experiment on habitability, which is designated M487. Certain criteria which make a habitable environment are postulated in this experiment. The experiment provides the equipment inside the SIVB which will put this hypothesis to the test. The habitability [58] of any environment is in large part a function of its food supply. It is the intent of M487 to make absolutely certain that there is nothing about the food system or any other system which will unnecessarily detract from habitability.
The AAP feeding system is one of the most critical elements of the overall life-support system of the AAP orbital assembly. Proper food consumption is essential for sustaining the health and performance of the astronauts. The quality of the food and the ease with which it may be prepared and consumed will have a profound effect upon the general psychological, as well as the physiological, well-being of the crew. Food which may be nourishing but which is not highly palatable and which is difficult to prepare and consume may adversely affect the morale and performance of the astronauts and will be incompletely consumed.
A second prime objective of AAP is to obtain medical data. A large complement of medical experimentation will be implemented on AAP in order to assess the effect of spaceflight upon the human and to gather predictive data regarding his ability to withstand weightless spaceflight of very prolonged duration. One part of this experimental package is designed to assess the effect of spaceflight upon musculoskeletal function. The core of the experiment is essentially a very precisely performed balance study, which is designated M070. Such a balance necessarily depends upon very accurate knowledge of the input and output of major metabolites.
The food must be sufficiently well defined that this knowledge of nutrient intake may be derived from minimal inflight data which will be recorded during the course of the experiment. The crew will adhere to a prearranged or nominal menu plan chosen by the principal investigator in advance. There will be available the crewman's daily log of items left unconsumed or of items consumed in a sequence which differs from the nominal menu. We will have an inflight logged recording and voice transmission regarding any residual, partially consumed food item which contains more than 1 percent of the original mass of food. Since these inflight mass measurements impose a burden on the crew, it is highly desirable that the food package be graduated in a manner which will allow a visual estimation of food mass remaining without mass measurement. As additional data, we will have assurance that the water content of any rehydratable food item will not differ from that prescribed by the instructions on the package.
We also propose to place on the AAP feeding system a number of nutritional requirements. It is essential that the recommended dietary allowances of all vitamins, minerals, essential fatty acids, and amino acids be met or exceeded by the nominal menu when completely consumed by the crew. The diet will be so designed that each crewman will consume each day about 800 mg of calcium. This might be accomplished either by distributing the calcium evenly in a constant calcium-to-calorie ratio throughout the food or by incorporating the calcium in items which the crewmember is most likely to consume first. Dietary phosphorus will be controlled in a similar manner.
The food flavor, texture, and appearance will be varied to obtain complete consumption. For purposes of designing the AAP feeding system, complete consumption will be considered the governing criterion for any increase or decrease in food variety. Complete consumption will ensure that the nutritional requirements of the crew are met as efficiently as possible without food [59] waste. Menus and food items will be varied in moisture content, flavor, texture, nutrient composition, and particle size in a manner which will ensure complete consumption. We would like to avoid unnecessary variety. Consideration will be given to a modular food concept which will consist of a few basic items which can be manipulated to provide the necessary variety in flavor, texture, moisture, particle size, etc.
The balance experiment will impose a requirement for as much homogeneity as possible. Ideally, rehydratable foods will be homogenous to the extent that any 1-percent sample of any food in a particular package will constitute a representative sample of that food. This requirement will apply to the food both in wet and dry state. Therefore rehydration of food items must take place completely and uniformly.
All food items to be included in the AAP menus will be of known chemical composition. The permissible variance in the nutrient composition of any food item will depend upon the number of items fed, but it must be low enough to be compatible with an overall requirement to ascertain the intake of each nutrient over a 56-day period to within 1 percent.
The food will be packaged in a manner which will facilitate complete consumption. At least 99 percent of the contents of any food package must be readily available to the crewman. As all food residue exceeding 1 percent of the original content of a package must be weighed or otherwise estimated, the foods must be packaged in a manner which will encourage complete consumption.
In order to adhere to the nutritional and experimental requirements of M070 and yet allow flexibility in the choice of the crew's menu items, consideration will be given to means of manipulating the food supply as the flight progresses. Computer programs will be developed which will generate menu choices within the required experimental envelope on the basis of food reported consumed and food known to remain.
I have just gone through a lot of requirements which seem largely to arise from the effort to conduct an inflight metabolic experiment. However, the primary requirement is to provide a feeding system which meets the demands of habitability. If there are experimental requirements that turn out to be obviously incompatible with the provision of a palatable flight menu, those requirements will not be imposed.
Now that we have levied numerous nutritional and experimental requirements on the feeding system, we must consider the type of environment in which these foods will be expected to function. The food must, of course, withstand the rigors of a launch with its associated stresses. The foods and food packages which constitute the feeding system of which I speak will be launched in three different sorts of vehicles; the Command Module, the Multiple Docking Adapter, and the Apollo Telescope Mount. The containers in which the food will be stowed will maintain a nitrogen pressure upon the food packages of at least 1 psi. Temperature will be maintained between 40° and 85° F. The food must be able to withstand these conditions, at their extremes, and allow variation thereof for a period of at least 8 months.
The weight allowance for food and flexible packaging will be generous in that it will permit the provision of at least double the caloric needs of the crew in the form of dry food. The packages [60] employed to protect the food will constitute only 10 to 12 percent of the weight of the food plus packaging.
The choice of the kinds of food is made considerably more flexible by the probable availability of a food-heating device such as a microwave oven and a food-cooling device (to 40° F). There will be a food-management area within the SIVB which will provide many of the amenities of a conventional eating location.
I have outlined the requirements of an AAP flight feeding system. These requirements will hopefully elicit solutions which are both imaginative and amenable to rapid implementation. I might reflect that much has been said of experimental requirements and of the supposed incompatibility of the two experimental sets which will be flown on AAP, i.e., habitability and medicine. AAP is, I like to believe, a precursor of much greater things to come. Before we progress to these future enterprises it is essential to glean all information possible from the opportunity which AAP will present. All experiments carried on AAP are of importance in this regard. We shall not compromise one for the other, but we shall optimize the quantity of information we obtain which will allow humans to endure mission profiles as removed from AAP as Apollo is from our first furtive orbital ventures.