"6_2_5_3.TXT" (1257 bytes) was created on 03-22-88 THE VERSATILE SPACE SHUTTLE: WORKHORSE OF THE NEW FRONTIER The Space Shuttle is the first reusable aerospace vehicle. It takes off vertically like a rocket. The winged orbiter then maneuvers in orbit like a spaceship. At the end of the mission the orbiter lands on a runway like an unpowered glider. The delta-winged orbiter is about the size and general shape of a DC-9 jetliner. The Shuttle orbiter can be used as an observation platfform, from which instruments can be focussed on the ground passing below, or objects in space of strong interest to astronomers. The orbiter can also carry a small but fully equipped manned laboratory, called Spacelab, for medical, scientific, engineering, and industrial experiments. Spacelabs have been flown on four successful missions. The pressurized modules remain in the cargo bay of the orbiter throughout the mission. One of the key attributes of the Space Shuttle is the relatively low acceleration and deceleration forces exerted on crew and passengers during launch and reentry. These forces reach a peak of 3 G's -- three times the force of gravity on the Earth's surface -- for a few minutes at a time. The strain is well within the limits which can be tolerated by healthy people. "6_2_5_4.TXT" (2013 bytes) was created on 03-23-88 THE ORBITER CREW COMPARTMENT The living space aboard an orbiter is relatively roomy and comfortable, compared to that in earlier manned spacecraft. There are two floors in the pressurized crew cabin located in the nose section. Together they provide 71.5 cubic meters (2,525 cubic feet) of space. The temperature can be regulated to stay between 16 and 32 degrees Celsius (61 and 90 degrees Fahrenheit). The top level of the cabin is the flight deck. Here the commander and pilot monitor and operate a sophisticated array of controls that are far more complicated than those of a giant jetliner. Behind their seats is a work area for mission and payload specialists. These crewmembers operate experiment controls, and check out and deploy spacecraft carried inside the large, unpressurized cargo bay. The bottom level of the cabin is the mid deck. This is the living quarters for the crew, although experiments that require air, such as plants and small animals, can also be carried here. The mid deck contains lockers for stowing crew equipment, and facilities for sleeping, eating, personal hygiene, and waste disposal. Air pressure inside the crew compartment is the same as Earth's at sea level: 1,033 grams per square centimeter (14.7 pounds per square inch). This atmosphere is made up of 80 percent nitrogen and 20 percent oxygen. Earth's atmosphere is 78 percent nitrogen, 21 percent oxygen, and one percent other gases, such as argon and neon. The crew members wear ordinary clothing. They don the bulky spacesuits only for extravehicular activities outside the cabin. Fans circulate the cabin air through cleansing filters, which are changed regularly. These filters contain activated charcoal to remove odor, and lithium hydroxide to remove carbon dioxide. Excess moisture is also removed, keeping the humidity at comfortable levels. The air in an orbiter is cleaner than that on Earth. Hay fever sufferers would welcome such a pollen-free atmosphere. WHAT SPACE TRAVELERS EAT The one, two, and three-person crews in earlier programs ate their meals out of containers or pouches, most commonly prepared by adding water and kneading the mixture by hand. The food was nutritious, but not very appetizing. The Space Shuttle carried eight people on one mission, and seven has been a common number. For these large crews, or missions planned to last for a week or more, a galley "mission kit" can be loaded in the orbiter mid deck. The mid deck galley includes special serving trays that hold the different food containers in place in microgravity. It also has a convection-type oven where packages of food are warmed before going into the trays. A small dining area, consisting of a table and several foot loops, is optional on each mission. The foot loops are floor restraints that help the astronauts steady themselves and remain in place while eating. If no galley is loaded aboard, the astronauts eat virtually the same meals, but they are heated inside a food warmer the size of a suitcase. Earth-bound chefs might envy meal preparation on the orbiter. One crew member can prepare meals for four people in about five minutes (excluding heating time). The orbiter does not normally carry a refrigerator because of the weight. If one is needed for biomedical experiments, and extra room is available, foods such as ice cream and frozen steaks may be added to the astronaut menu. About half the Shuttle foods and beverages are preserved by dehydration, which saves both weight and storage space. There is ample water for rehydration, since the fuel cells that power the orbiter produce it as a by-product when generating electricity. (Both hot and cool water are available.) Some foods are thermo- stabilized -- that is, heat-sterilized and then sealed in conventional cans or plastic pouches. A few, such as cookies and nuts, are available in a ready-to-eat form. Meals in orbit are both tasty and nutritious. The menu includes more than 70 food items and 20 beverages. With so many different choices available, astronaut crews can have a varied menu every day for four days. What are these meals in space like? The menu for a typical day might start with orange drink, peaches, scrambled eggs, sausage, cocoa and a sweet roll for breakfast; cream of mushroom soup, ham and cheese sandwich, stewed tomatoes, banana and cookies for launch; and shrimp cocktail, beefsteak, broccoli au gratin, strawberries, pudding and cocoa for dinner. The carefully selected menus provide about 3,000 calories per person daily, although crew members are not required to eat that much. Previous space missions demonstrated that astronauts need at least as many calories in space as they do on Earth. Meals served on the Space Station, at least at the beginning, will resemble those available on the Space Shuttle. Later, perhaps small vegetable gardens will supply fresh produce, as well as absorb carbon dioxide from the atmosphere while supplying oxygen for the crew. "6_2_5_6.TXT" (2701 bytes) was created on 03-22-88 SANITATION IN ORBIT Sanitation is more important within the confines of a spaceship or space station than on Earth. Studies have shown that the population of some microbes can increase extraordinarily in microgravity and confined spaces. This means many infectious illnesses could easily spread to everyone aboard. The eating equipment, dining area, toilet, and sleeping facilities in an orbiter are regularly cleaned, to prevent the growth of microorganisms. Since there is no washing machine aboard, trousers (changed weekly), socks, shirts, and underwear (changed every two days) are sealed in air tight plastic bags after being worn. Garbage and trash are also sealed in plastic bags. Shuttle travelers don't have to do many dishes. Food containers go into the plastic bags, and eating utensils and trays are cleaned with wet wipes. A favorite early question of people interested in space was how the astronauts took care of digestive elimination. The orbiter travelers use a toilet that operates very much like one on Earth. A steady flow of air moves through the unit when it is in use, carrying wastes to a special container or into plastic bags. The container can be opened to vacuum, which exhausts the water and dries the solids, and the plastic bags, when used, can be sealed. Some of the wastes may be returned to Earth for postflight laboratory analysis. In the past, such analyses have helped doctors understand how the body functions in microgravity, including data on which minerals the body loses in unusual amounts. Unlike Skylab, which had an enclosed shower, Shuttle travelers can only take sponge baths in space. Water droplets float about in weightlessness, creating a potential hazard for electrical equipment. Water is obtained from a handgun, where the temperature can be set at any comfortable level from 18 to 35 degrees C (65 to 95 degrees F). Dirty water from the sponge is squeezed into an airflow system which conveys it to the orbiter's waste collection tank. Whiskers cut off in shaving could also become a nuisance if they floated about, with a potential to damage equipment. Male astronauts can avoid this problem by using conventional shaving cream and a safety razor, then cleaning off the face with a disposable towel. The sleeping and sanitary arrangements for the Space Station are still in the design stage. Engineers are drawing on the experience gained in earlier manned space flight programs to plan systems that will be more like those on Earth. Eventually, a visitor to the Space Station should be able to eat a meal or use the sanitary facilities without special instructions. "6_2_5_7.TXT" (1807 bytes) was created on 03-22-88 SPACESUITS AND RESCUE EQUIPMENT In earlier programs spacesuits were tailor-made for each astronaut, a time-consuming and expensive process. Now only the gloves are custom-fitted. The Shuttle spacesuit is made in small, medium, and large sizes, and can be worn by either men or women. The suit comes with an upper and lower torso, equivalent to a shirt and trousers, and the two pieces snap together with seal rings. A life- support system comes built into the upper torso. All earlier versions had separate support systems that had to be connected to the suits. The Shuttle spacesuit is lighter, more durable, and easier to move about in than its predecessors. It is only used for an extravehicular activity (EVA) outside the crew cabin. The astronauts wore pressure suits, of the kind worn by military jet pilots, during early test flights. Now they wear regular clothing. Only two spacesuits are normally carried on a flight. If a transfer from one vehicle to another should be necessary in the future, personal rescue enclosures are available for the remaining crew members. These are 83.36 centimeter (34-inch) diameter (when pressurized) spheres, each containing life support and communications gear. In an emergency in space that required abandoning the orbiter, two astronauts would don the spacesuits and, if needed, the Manned Maneuvering Units (MMUs). The latter have built-in propulsion systems. The rest would enter the personal rescue enclosures. The two suited astronauts would transfer their crewmates to the rescue ship. This could be accomplished by rigging a pulley and clothesline device between the two vessels, using the Canadarm Remote Manipulator System, or physically towing the enclosures through space with the power of the MMUs. "6_2_5_8.TXT" (1516 bytes) was created on 03-22-88 RECREATION AMD SLEEPING Just as on Earth, recreation and sleep are important to good health when working in space. Astronauts perform a scientifically planned exercise program, largely to counter the atrophy some muscles experience in a weightless environment. Cards and other games, books, and taped music can be taken aboard. Tape recorders are available. Sleeping accommodations aboard the Shuttle vary, depending on the requirements of the particular mission. On the first flight, astronauts Young and Crippen slept in the commander and pilot seats. They wanted to be instantly available if needed. Later crews slept in their seats, in sleeping bags, in bunks, or by simply tethering themselves to the orbiter walls. The sleeping bags are cocoon-like restraints attached to the lockers where crew provisions are stored. In microgravity there is no 'up,' and the astronauts can sleep as comfortably in the vertical position as the horizontal. A bunkbed kit was available by the time of the STS-9 mission. Crew members could sleep in three horizontal bunks when these were installed, and an extra vertical bunk was available if needed. Each bunk comes complete with an individual light, communications station, fan, sound suppression blanket, and sheets with microgravity restraints. The bunks even have pillows. When the bunks must be removed to allow room in the mid deck for experiments or extra equipment, up to four optional sleeping bags can be used instead. "6_2_5_9.TXT" (3625 bytes) was created on 03-22-88 THE CONTINUING CHALLENGE OF MICROGRAVITY Many of the problems that arise from living and working in space have been resolved. However, some of the physiological affects of weightlessness are still not completely understood. Among these are the leaching of certain minerals from bones; atrophy of muscles when not exercised; and space adaptation syndrome, a form of motion sickness found only in spaceflight. All the deleterious effects of living in microgravity disappear after an astronaut returns to the ground. Some can be countered while in orbit by special diet and exercise. But even a vigorous exercise program does not appear to stop bone loss, or the decrease in the rate of normal bone formation. NASA is engaged in a long-term program to understand the causes underlying these changes, in order to develop ways to prevent them. This will be particularly important for the longer tours of duty on the Space Station, where crew members will be in orbit for three months or more at a time. The Space Station NASA is now planning and designing is a large facility. It will be resupplyable and capable of staying in orbit indefinitely, unlike Skylab. Many of its systems will be highly automated, leaving the crew more time for the tasks that can only be performed by humans. Present plans call for the initial configuration to be in operation by the middle of the 1990's. The Space Station will be a permanent, multi-purpose facility operating in orbit. It will serve as a laboratory, to conduct long- term basic research in the almost perfect vacuum and microgravity of space; a manufacturing plant, to make exotic metal alloys, super-pure pharmaceuticals, or perfect crystals; a spacecraft garage and repair facility; and a base for the assembly in orbit of other large structures. It will also support nearby free-flying Earth observation, astronomy, and materials processing platforms, among many other applications. There will a tremendous amount and variety of work to do. Initial plans call for a crew of six to eight people in the operational Space Station, supported by resupply and crew rotation flights of the Space Shuttle every three months. One major advance planned for the Space Station is a closed-cycle environmental control and life support system. The oxygen will be recovered from the carbon dioxide exhaled by the crew, and the wash water, urine, and condensate will be purified and reused. Present planning calls for only food and nitrogen to be periodically resupplied from Earth. The Space Station Revised Baseline Configuration features a 110-meter long horizontal boom to which pressuried modules are attached in the Center. One of the modules is a habitat, and the other three are laboratories provided by the U.S., the European Space Agency, and Japan. The standard module will be 13.3 meters (43.7 feet) long and approximately 4.5 meters (15 feet) in diameter. They will be connected by tunnels and various support structures. The Space Station will provide far more working and living room than any earlier facility designed to operate in space. Several other nations and space organizations are working cooperatively with NASA to design and build some components of the Space Station. They too will have personnel living and working aboard. The Space Station has been called "the next logical step" in the continuing exploration and utilization of space, the new frontier mankind has only started to explore. Improving the living and working conditions of the people involved is an important part of the total effort. "6_2_5_10.TXT" (5452 bytes) was created on 03-25-89 FLASHBACK FOR THE SPACE BACKPACK Reprinted from the February 3, 1989, issue of Space News Roundup, a publication of NASA's Lyndon B. Johnson Space Center, Houston, Texas Manned maneuvering unit celebrates fifth anniversary On Tuesday, it will be exactly five years since astronaut Bruce McCandless pushed a lever and became the first space walker to fly freely above Earth. McCandless' untethered flight with the manned maneuvering unit (MMU) was the fruition of a dream that had been moving toward reality since the early 1960s, a dream enjoyed by many at JSC. This center managed and performed much of the work on the MMU, which was built by Martin Marietta. On Feb. 7, 1984, McCandless piloted the nitrogen-jet propelled MMU a little more than 100 yards from Challenger, creating a scene of space-age freedom that became immediately famous as it fired the public imagination. McCandless was accompanied by astronaut Bob Stewart who flew a second MMU. Together, the two tested the units and found their performances flawless. It was a triumphant moment for both McCandless and Ed Whitsett, project engineer for the MMU and a man involved with the concept since his graduate thesis in 1960. The two had worked together on the MMU off and on for about 16 years. "We had a lot of confidence in it. We knew it was a good machine," Whitsett said recently. "But, obviously, the first time he flew away from the Shuttle, a lot of people were uptight." That was not the case for McCandless. "I had lot of confidence in the hardware," he said. "I knew that the laws of physics hadn't been repealed recently." McCandless said he experienced no new physical sensations as he became, essentially, a second spacecraft. After having been in orbit aboard Challenger for four days, the only difference he felt in the MMU was "a sense of professional satisfaction." "I did not feel alone or isolated," he remembered. "I attribute that largely to excellent radio communications. Vance (Brand) and the guys were reading off ranges and talking to me, so I didn't feel I was isolated." The first flight was the result of development work that began with an awkward, difficult-to-control, hand-held maneuvering unit used during the Gemini program. The work proceeded through the Skylab missions, where crew members evaluated another hand-held unit, a device called "jet shoes" and the first backpack thruster unit. Among these three, the backpack, flown by five different astronauts for a total of 14 hours within the orbital workshop, easily won. Development of the MMU during the Shuttle program was spurred, at first, by a desire to have a method the crew could use to inspect the bottom of the Orbiter in flight, Whitsett said. But its major use, and the event that put its operation in high gear, was a need for satellite retrieval and repair. McCandless' flight was a dress rehearsal for repairs of the Solar Maximum Mission satellite. The MMU was used on two following Shuttle flights to work with three satellites_Solar Max, Westar VI and Palapa B-2. All of the flights took place within a year, and, in total, six astronauts have flown MMUs for a combined 10 and a half faultless hours. MMUs aren't currently scheduled for any future flights, although it is possible they will be used for a Space Station Radiator Assembly Demonstration (SRAD) flight experiment sometime in 1993. Still, Whitsett said, one can never tell when the need could arise for an MMU mission. "The Westar and Palapa mission wasn't planned far in advance. It just happened that the MMU was needed," he explained. The MMUs, proven dependable fliers, are in storage now at Martin Marietta. "They're in good shape, able to be used whenever the need arises again," McCandless said. Completing development of the MMU, a project that spanned so many years, was a little bittersweet for those devoted to it. "Everybody who worked on it was extremely enthusiastic. People were nearly fighting to get on the project," Whitsett said. "It's sort of like raising a child. When they go off and get married, you're still proud of them. But they're not there anymore." Many of those involved with development and flight of the MMU plan to honor the fifth anniversary of the first flight on Tuesday. The MMUs remain ready and waiting as they are, but they may be improved by work now under way on the Extravehicular Activity (EVA) Retriever, a fetching space robot being developed at JSC. "A lot of the retriever work will feed into MMU updates, such as a fault detection system and caution and warning lights," said Whitsett, who now works as systems integration manager for space station EVA systems. McCandless also has special ideas for the future of the MMU. "I'd dearly love to see us mount the IMAX camera on the MMU for a flight," he said. "You could get stand-off imagery of the Orbiter with Earth in the background. I think that would be very dramatic." McCandless said he does have one minor regret about the first MMU flight. "I had intended when I got out 30 feet or so to stop and face away from Orbiter and look at the cosmos," he said. "I forgot; I was concentrating on watching the Orbiter." McCandless is now deeply involved in preparing for another Shuttle flight, STS-31. Scheduled for December, the mission's primary objective will be to deploy Hubble Space Telescope. -END-