EP-165 Spacelab

two illustrations of spacelab processing

"Step right in, ladies and gentlemen! Welcome to Spacelab! This is the real thing. Not a mockup. Not a replica. The module in which you are standing has flown in space 178 days. Seventy-five Shuttle missions have carried Spacelab pallets or modules. This module was used on 20 flights, and it carried crews totaling 126 men and women through 2,848 Earth orbits. In those crews were 83 scientists - 71 men and 12 women - who worked as mission specialists and payload specialists and carried out 476 scientific and technological experiments in orbit. Among the many historic discoveries they made was...."

 

CHAPTER TWO: A Sightseer's Tour of Spacelab of Spacelab.

 

[13] One of the volunteer tour guides at the National Air and Space Museum in Washington, D.C., is speaking. It is near the turn of the century-perhaps 15 years from the first Spacelab flight in 1983. One of the two sets of Spacelab components-a long module and five pallets and various units of auxiliary equipment-is now part of the Air and Space Museum's permanent "Milestones-of-Manned-Flight" exhibit.

The other identical set of Spacelab components joined the permanent collection of a major museum in Europe. In addition to their normal Shuttle use both sets had put in short tours as experimental research and application modules with the U.S. space station launched in the 1990s. The modules loaded with experiments, were repeatedly taken into orbit aboard the Shuttle and staved there attached to the space station for periods up to three months. The modules were then returned to Earth by the Shuttle, unloaded, re-equipped with other experiments, and launched once again for more research at the space station.

This scenario is imaginary, of course. Figures given by the fictitious tour guide are merely projections and extrapolations. So are all of the statements about the two sets of Spacelab. But if the expectations of the European builders and NASA operators of Spacelab materialize, its history may closely parallel this scenario and these figures.

The first Spacelab-built and funded in Europe-is complete and ready for service beginning in late 1983. The second Spacelab is being purchased by NASA from its European builders and is expected to be ready for service in 1985. Each of these Spacelabs is designed for as many as 50 missions.

When these Spacelabs are eventually retired to become museum exhibits, they will differ in some important ways from earlier displays of the relics of manned space flight.

Tourists cannot wander into the earliest habitable enclosures flown in outer space- Mercury, Gemini, the Apollo command module, and the Apollo lunar landing module, which were the first U.S. manned spacecraft. All are far too small for sightseers to enter. Most of the units on museum display are sealed, but have transparent walls or windows through which visitors can look inside. Skylab, the largest U.S. habitable space enclosure, is big enough so that groups of visitors do walk through it at the National....

 


Training inside a replica of the long module are the payload specialists for the first Spacelab flight.

Training inside a replica of the long module are the payload specialists for the first Spacelab flight. From left: Dr. Byron K. Lichtenberg and Dr. Michael L. Lampton, both from the United States. Wubbo Ockels (kneeling) from the Netherlands, and Dr. Ulf Merbold from West Germany. Lichtenberg and Merbold are in the flight crew; Lampton and Ockels are alternates.

 

[14] ....Air and Space Museum's display. But Skylab (like the lunar module) was abandoned in space after its usefulness, was exhausted. The flight unit is gone. Exhibits are made up of unflown duplicates or mockups.

 

All of Spacelab Returnable

Not so with Spacelab. Every part of it-and everything it carries with it-comes back to the Earth after each flight. In the words of the fictitious museum guide, "the real thing" with all its furnishings and auxiliary equipment can go on display once the units are withdrawn from flight duty. There is ample room for small groups of tourists to gather in its interior.

Spacelab's long module-7 meters (23 feet) long and 4 meters ( 13 feet) in diameter- combines the core and experiment segments and has the dimensions of a medium-size house trailer. Its 5.4-meter-long ( 18-foot ) center aisle is a suitable place for the tour to begin.

What the museum visitors see from the aisle looks much like the scene in other modern research laboratories: Walls are lined with the standard 48-centimeter-wide ( 19-inch) laboratory racks containing custom made instruments and equipment. One sees switches, status indication lights, intercom stations, keyboards, several display screens. There is a workbench for making minor equipment repairs and adjustments. It looks like a lectern and will be used also as a writing desk.

Stowed in racks and overhead ceiling bins, resembling the storage compartments above passenger seats in planes and trains, are common laboratory supplies and utensils- film, magnetic tape, cameras, test tubes, lab cultures, material samples, spare parts, lubricants, and repair tools, including wrenches of different sizes, screwdrivers, knives.

Yet any notion that this is an ordinary laboratory is quickly dispelled. Even....

 


Long module and pallet being readied for loading into the Orbiter's cargo bay at the Kennedy Space Center in Florida.

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Long module and pallet being readied for loading into the Orbiter's cargo bay at the Kennedy Space Center in Florida.

Long module and pallet being readied for loading into the Orbiter's cargo bay at the Kennedy Space Center in Florida.

 

[15] ...sightseers unfamiliar with research installations notice that this is an unusual facility. Handrails are within easy reach from any location. So are foot restraints. Items in the stowage racks are surrounded by foam filler. Test tubes are closed to keep fluids from floating away. There are no doors. The entrance is a tunnel (which has been removed along with the end cone, to permit tourist access ).

This is a laboratory adapted for work in weightlessness.

Mobility aids such as rails and restraints are needed for comfort and safety in an environment in which the reaction from closing a drawer or stomping a foot can send a crew member gliding through the air. Unattached objects must be fastened to prevent them from floating away and causing injury or damage.

 

Modular Concept Featured

Interior furnishings are modular, so that they can be removed, exchanged, or rearranged in various combinations to serve the needs of specific missions.

The core and experiment segments each have space for two double racks and one single rack on each wall-a total of eight double and four single racks in the entire long module.

 


Testing research instruments at laboratory racks inside module, two technicians wear protective clothing to avoid contamination of equipment. Note vertical railing for crew's use in weightlessness.

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Testing research instruments at laboratory racks inside module, two technicians wear protective clothing to avoid contamination of equipment. Note vertical railing for crew's use in weightlessness.

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Experiment racks (right foreground) and flight module (center background) are tested in Bremen, West Germany, before shipment to the United States.

 

Experiment racks (right foreground) and flight module (center background) are tested in Bremen, West Germany, before shipment to the United States.

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Spacelab module in preparation for flight in Operations and Checkout Building, Kennedy Space Center, Florida. In background is engineering model.

Spacelab module in preparation for flight in Operations and Checkout Building, Kennedy Space Center, Florida. In background is engineering model.

 


 

[16] The first double rack on the port side of the core segment-as seen when entering the module from the tunnel-is called the Control Center. It houses the console of the Control and Data Management System (CDMS) which is for all practical purposes the brain and nerve center of Spacelab. Its keyboard and video display are the crew's interface with Spacelab's systems. Here the crew obtains readouts informing them of the status of Spacelab's systems and experiments. Here too the crew can command the computers and operate many of the experiments within the module and on the pallet. And here too the crew can adjust the cabin temperature, switch communication modes and do trouble shooting when needed.

In the first double rack on the right- directly across the aisle from the CDMS controls-are the work bench-desk assembly and also the computers which are controlled from the CDMS.

With these first two double racks taken up by controls and computers, only two double racks and two single racks remain available in the core segment for experiments. In the experiment segment, all racks are available for experiment instruments and equipment.

All racks are independently attached to the floor and overhead structure. Racks not needed on a particular mission can be removed. Up to 290 kilograms (645 pounds) of equipment and instruments can be installed in each single rack, up to 580 kilograms (1,290 pounds) in each double rack.

 


Scientific airlock in the ceiling of the experiment segment allows exposure and retrieval of experiments to outer space without requiring crew members to leave enclosures.

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Looking straight up in the core module, as the camera did here, a visitor sees two windows in the ceiling through which crew members can make astronomical and Earth observations.

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Scientific airlock in the ceiling of the experiment segment allows exposure and retrieval of experiments to outer space without requiring crew members to leave enclosures.

Looking straight up in the core module, as the camera did here, a visitor sees two windows in the ceiling through which crew members can make astronomical and Earth observations.

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Racks are tested again after arrival at the Kennedy Space Center, Florida.

 

Racks are tested again after arrival at the Kennedy Space Center, Florida.

 


 

[17] Instruments and equipment are thoroughly tested before being lifted into and installed in the module and on the pallets. Then, the entire Spacelab assembly as needed for a mission- module, pallets, and the instruments and equipment they carry- are jointly tested to assure their compatibility. Only hen, after they have been checked out together, are the fully loaded modules and pallets installed in the cargo bay, thus keeping the Orbiter free for other assignments as long as possible and reducing its turn-around time, the period between its landing and next launch.

Looking up, the visitor notices that the overhead storage lockers are interrupted twice, first by windows in the ceiling of the...

 


Location of Racks.

Location of Racks.

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Two inside views of the habitable module during different phases of preparation.

Two inside views of the habitable module during different phases of preparation.

 

Two inside views of the habitable module during different phases of preparation.

 

[18]... core segment, and second by a large protruding cylinder in the ceiling of the experiment segment On which a tall visitor who is not careful might bump his head.

 

View from Module Limited

These windows-plus another set at the rear end cone-provide the only outside view for crews in the Spacelab modules. Without these windows life inside Spacelab would be much like working in a submerged submarine. The windows can be used for celestial and terrestrial observations.

One of the windows in the ceiling assembly is rectangular, measuring 41 by 55 centimeters ( 16 by 21.5 inches), and is called the high-quality window because it is made of nearly distortion-free, low-reflective glass reflective glass for observations requiring great precision. Temperature sensors on this window warn crews of the glass's overheating due to excessive Sun exposure.

The other window in the assembly is 30 centimeters ( 12 inches) in diameter and is made of conventional glass containing a heater film coating to prevent fogging from condensation. Through it the crew makes observations and takes photographs requiring less precision.

When the windows are not in use, the crew can protect the entire assembly from micrometeoroid impacts, contamination, and overheating with covers that can he controlled from inside the modules. In flight, crew members can look through the aft end cone's viewport onto the pallets and the instrumented mounted there.

 


Spacelab-1 module in the checkout facility at the Kennedy Space Center in Florida.

Spacelab-1 module in the checkout facility at the Kennedy Space Center in Florida.

Spacelab-1 module in the checkout facility at the Kennedy Space Center in Florida.

 

Airlock Chamber Provided

The large cylinder in the ceiling opening in the experiment segment contains an airlock through which the crew can expose instruments and specimens directly to outer space. They can be retrieved later without any crew member having to go outside the module.

The airlock is a cylinder one meter (3.3 feet) long and one meter wide. It is closed by hatches at troth ends. Experiments to he exposed to space are attached by the crew to a sliding table that can carry loads of up to 100 kilograms (220 pounds). The airlock's inner hatch has a small viewport for monitoring the exposed experiment. It takes the crew about 10 minutes to drain the air from the airlock before exposure of samples or instruments to the vacuum of space. About 15 minutes are needed to repressurize....

 


The engineering model, a replica of the flight unit, is hoisted onto a work stand

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The engineering model, a replica of the flight unit, is hoisted onto a work stand at the Operations and Checkout Building at the Kennedy Space Center, where engineers and technicians then practice installing equipment (middle).

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The engineering model, a replica of the flight unit, is hoisted onto a work stand (top) at the Operations and Checkout Building at the Kennedy Space Center, where engineers and technicians then practice installing equipment (middle). After it was assembled in Bremen, West Germany, the model was tested there (bottom) before being shipped to the United States. Engineering models are used to train personnel and to check the compatibility of auxiliary equipment and the assembly facilities.

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After it was assembled in Bremen, West Germany, the model was tested there (bottom) before being shipped to the United States. Engineering models are used to train personnel and to check the compatibility of auxiliary equipment and the assembly facilities.

 

[19] ....the airlock with nitrogen before experiments are retrieved. Several repressurizations are possible on each Spacelab flight with the supply of nitrogen aboard the module.

If no airlock is needed, the window assembly from the core segment can be installed in the airlock opening in the experiment segment. Otherwise, the ceiling opening is closed with a cover plate. (The airlock cannot be mounted in the core segment opening.)

Some important features of Spacelab are not readily discernible during a casual visit.. Among these less obvious items are the intricate systems that keep the atmosphere clean and the humidity and temperature comfortable for the crew.

Water and air flow through the cooling loops of Spacelab's environmental control system, carrying away heat generated by the bodies of crew members, by the extensive electronic equipment, and by other instruments within the module. Because air does not circulate by itself in weightlessness as it does on the Earth, where warm air rises and colder air sinks, air must be forced under pressure through the equipment racks and other portions of the module.

Spacelab temperatures are kept even with the help of a passive environmental control system, which consists of many layers of foil-covered Mylar with a vacuum between layers. Special paint on the outside helps ward off the Sun's intense heat on one side and the extreme cold of space on the shadow side.

 


When the floor panels are removed in the long module, utility system installations are exposed. Shown are portions of environmental control and electric power distribution systems in module's subfloor.

When the floor panels are removed in the long module, utility system installations are exposed. Shown are portions of environmental control and electric power distribution systems in module's subfloor.

 

Temperature and Clean Air Management Provided

In orbit the environmental control loops carry their cooling fluids (water and air inside the module, freon outside the module) to the cargo bay doors, where radiators attached to the doors dissipate the heat into space. During launch and landing, when the doors are closed, the loops unload their heat to the Orbiter's flash evaporators, which boil off ammonia. Water evaporators in the Orbiter augment the system in orbit when the radiators cannot dissipate the total heat load.

Some of the cooling loops (air ducts and fluid lines) run under the module's floor. Electric power, communications, data transmission, and other utility lines are also located there. Some underfloor storage space for equipment and supplies is available in the experiment segment. Some floor panels are removable m both segments. Thus crew members have limited access to the subfloor space for adjustments and minor repairs, for changing the lithium hydroxide canisters for carbon dioxide removal, and for retrieving items stored in the experiment segment's underfloor bins.

Instruments and equipment requiring extra cooling in the equipment racks inside the module or on pallets can be accommodated with "cold plates" that can be attached to such instruments. Each cold plate is made up of a pair of metal sheets forming a sandwich around tubes through which coolants are cycled.

The environmental control system provides an atmosphere for Spacelab's crew inside the module with the same air pressure and composition as at sea level-14.7 pounds per square inch ( 10.1 Newtons per square centimeter) with approximately 20 percent oxygen and 80 percent nitrogen-and with room temperatures which the crew can set to their own liking. Oxygen is supplied by the Orbiter. The module carries its own nitrogen supply. The atmosphere is continuously strained through the lithium hydroxide canisters to remove carbon dioxide and occasionally is also cycled through a scrubber [20] to remove contaminants. A vent assembly in the forward end cone expels noxious fumes from experiments directly into space. The assembly's hose can be connected with the experiment chambers in the racks to vent undesirable gases into the vacuum outside.

 

Fuel Cells Furnish Power

Despite the abundance of sunshine in space, the Orbiter and Spacelab do not draw any power from solar cells. None are aboard. Instead, electricity is generated aboard the Orbiter by three fuel cells, one of which is entirely devoted to Spacelab. Part of the.....

 

Technicians at work on the first Spacelab flight unit.

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Technicians at work on the first Spacelab flight unit.

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TDRS closeup: Sixteen-foot (4.8-meter) dish antennas project from this TDRS in an artist's concept of a satellite's eye view of the Earth. The paddle-like blue rectangles on long booms are solar panels for powering the satellite.

TDRS closeup: Sixteen-foot (4.8-meter) dish antennas project from this TDRS in an artist's concept of a satellite's eye view of the Earth. The paddle-like blue rectangles on long booms are solar panels for powering the satellite.

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Two satellites - shown here in the upper left and right corners comprise NASA's new Tracking and Data Relay Satellite System (TDRSS, pronounced "tea dress") which is to serve Spacelab and the Orbiter, and numerous applications and science satellites. A third TDRS is to be kept in orbit as a spare. From their Earth-synchronous orbit each TDRS covers about half the globe for relaying communications between orbiting craft and the Earth station at White Sands, New Mexico.

Two satellites - shown here in the upper left and right corners comprise NASA's new Tracking and Data Relay Satellite System (TDRSS, pronounced <<tea dress>>) which is to serve Spacelab and the Orbiter, and numerous applications and science satellites. A third TDRS is to be kept in orbit as a spare. From their Earth-synchronous orbit each TDRS covers about half the globe for relaying communications between orbiting craft and the Earth station at White Sands, New Mexico.

 

 

[21] .....output of one of the two other fuel cells can also be made available for Spacelab if needed.

Fuel cells, which produce electricity from supercold liquefied oxygen and hydrogen by a chemical process, have been successfully used in U.S. manned spacecraft throughout the Apollo flights beginning in the late 1960s. For Spacelab operations fuel cells are advantageous because the crew is free to position the Orbiter to suit research needs for astronomical or Earth observations, rather than having to move the Orbiter so that its solar cells face toward the Sun for extended periods to charge its batteries. Fuel-cell-generated electricity from the Orbiter is distributed to Spacelab outlets in the module work areas, the equipment racks, and at the pallets to operate the instruments and equipment there. The water that is produced by the fuel cell chemical reaction is used for food preparation, drinking, and evaporative cooling.

Power also goes to Spacelab's three computers-one for supervision of the experiments, another for controlling Spacelab's own housekeeping, and the third as a backup for immediate substitution if either of the others fail.

Museum visitors can stand at a video screen of the Control Center console and watch a payload specialist operate the keyboard while Spacelab information appears on the screen. The watcher can get a quick look analysis on the screen about any Spacelab experiment-Is it turned on? What results is it getting? Are there any problems? If so, what are they? Besides acquiring this and other information and making it available to the crew, Spacelab's on-board computers also supervise the multiplexing of the various communication channels into a single data stream, activate the high data-rate and video recorders, and command transmission to Earth.

The computers operate some experiments virtually without human intervention, adjusting deviant instruments back to accuracy within split seconds. They flash a warning if assistance from the crew is required or if an emergency should appear to be imminent. Crew members can enter new instructions into the computers and also override its decisions.

 

Sixteen Data Channels Available

The computer-associated mass memory can store 132 million bits of data, a quantity which, if it were all stored in words, would be the equivalent of 27 thick books. The computers and the rest of the Control and Data Management System (CDMS) operate separately from the Orbiter data management installations, thus making the CDMS the most independent of all major systems aboard Spacelab. However, for transmissions to Earth, the CDMS depends entirely on the Orbiter's communications system. All of Spacelab's communications and data transmissions go through the Orbiter.

One of the key devices for feeding data to the Orbiter's communications system is a very advanced multiplexer which combines 16 channels of instrument information and two voice channels for simultaneous transmission. A crew member in the Orbiter can carry on a conversation with Earth while another crew member in the module talks to the Earth on another voice channel. At the same time, 16 research instruments aboard Spacelab can report their condition and their research results to Earth.

For transmission the Orbiter uses the new Satellite Tracking and Data Relay Satellite System (TDRSS). When completed, that system's transmission of data, voice and television from the Orbiter can be raised to a rate at which, if the transmissions were all in alphabet characters, would equal nearly a million words-or 10 full-length novels- moving from space to Earth each second. With the full TDRSS in operation, contact can be maintained with Mission Control at least 30 to 80 percent of the time.

 

[22] Tunnel Provides Module Access

At the front end of the module in the center of the end cone-between the double racks holding the Control Center and the workbench-desk-is the entrance to the tunnel that leads to the Orbiter's mid deck. The tunnel, the only major in-orbit component of Spacelab supplied by NASA, comes in two lengths to permit positioning the modules closer or farther away from the Orbiter's flight and mid decks. This flexibility in the module's placement is necessary to maintain the Orbiter's desired center of gravity under varied loading conditions. Since Spacelab's length varies depending on the configuration used- whether a long or short module or one or more pallets are carried-loading conditions differ for each flight.

The tunnel is wide enough so that crew members after some practice can carry packages of up to 56 by 56 by 127 centimeters (22 by 22 by 50 inches) through it from the mid deck to the modules. This makes it possible to store some Spacelab supplies in the Orbiter mid deck.

 


Tunnel is being fitted to long module during tests at the Kennedy Space Center in Florida.

Tunnel is being fitted to long module during tests at the Kennedy Space Center in Florida.

 

[23] Through a hatch near the tunnel's junction with the Orbiter's mid deck, space-suited crew members can pass outside on extravehicular activities (EVA), also known as space walks. Some flights call for such EVAS to carry out experiments in the vacuum of space. Unscheduled EVAS can become necessary, for maintenance and repair work on pallet-mounted instruments, or on the cargo bay doors' closing mechanisms, or on other Orbiter or Spacelab components.

In pallet-only missions-when no module is on board-a vertical drum, 2.4 meters....

 


Z-shaped tunnel arrives for installation in Orbiter's cargo bay.

Z-shaped tunnel arrives for installation in Orbiter's cargo bay.

 

.....high and weighing 630 kilograms ( 1,400 pounds) is attached to the forward pallet to provide services otherwise offered by the modules. The drum is called an "igloo" and maintains the same interior temperature and atmosphere as a module. The igloo contains necessary power-distribution, command and data equipment and other utility resources to serve pallet instruments. In the pallet-only configuration, the research instruments and utility installations are controlled from the Orbiter's aft flight deck or from the ground.

Special services for experiments which require them can be made available by the Orbiter-Spacelab system. For example, telescopes often need to be kept pointed for relatively long periods with extraordinary precision at very faint, extremely distant celestial targets. The Orbiter's maneuvering ability using the thrusters of the reaction control system rarely exceeds an accuracy better than one-half a degree and often comes within only two degrees of accuracy- roughly equal to holding an instrument on the Earth pointed at the full disk of the Moon.

 


The one-ton Instrument Pointing System manufactured in Europe is used on pallets whenever telescopes need to be focused with great precision.

The one-ton Instrument Pointing System manufactured in Europe is used on pallets whenever telescopes need to be focused with great precision.

 

[24] Pointing Device Provided

For very precise aiming, an Instrument Pointing System (IPS) is being developed by the European Space Agency. Weighing about a ton, the IPS is installed on a pallet whenever it is needed on a mission, to focus instruments on their targets with an accuracy within 1.2 arc-seconds. This is equal to keeping an instrument on the Capitol steps in Washington, D.C., aimed at a dime-size coin at the Lincoln Memorial 3.6 kilometers (2 1/4 miles) away. The IPS keeps instruments on target even when crew movements or equipment operations cause the Orbiter to vibrate. The IPS can be programmed to work automatically or it can be controlled from the Orbiter's flight deck. As a safety precaution in the event that the IPS cannot be retracted and restowed after use, thus preventing the cargo bay doors from closing for reentry, the entire IPS can be jettisoned into space, as can the airlock outer hatch if it should fail to retract.

To avoid flying over land areas during early ascent, flights launched from Kennedy Space Center in Florida are not sent into orbits with an inclination steeper than 57 degrees. However, this permits orbital paths that bring Spacelab far enough north to cover all of the United States, the southern half of Canada, all of Central Europe and all except the most northerly parts of Asia-and far enough south to pass over all the major land masses in the Southern Hemisphere except Antarctica. When Shuttle launch facilities are completed at the Vandenberg Air Force Base in California, the Shuttle can be launched into orbital inclinations permitting Spacelab to overfly nearly the entire earth. Altitudes....

 


<<Igloo,>> being readied for use, holds Spacelab computers and other vital equipment in pallet-only flights.

"Igloo," being readied for use, holds Spacelab computers and other vital equipment in pallet-only flights.


Orbiter's aft flight deck & Orbiter's cabin

Orbiter's aft flight deck & Orbiter's cabin.


 

 

[25] .....obtainable for Orbiter-Spacelab flights depend on the loads carried and on desired inclinations. Altitudes may range from about 160 to 400 kilometers (about 100 to 250 miles).

Despite its variety of components and systems and the complexity of its tasks, Spacelab required no major technological breakthroughs. Its innovative design and construction are based on well-established engineering principles and proved techniques. Checks and tests to which Spacelab was subjected are conservative procedures followed painstakingly by ESA and NASA to assure the safety of all systems intended for space flights with human crews

A tour through Spacelab is much more than a walk past a hallmark collection of engineering achievements. As with many other multifaceted engineering entities, with Spacelab the whole adds up to more than the sum of its parts.

Spacelab is a tool for doing old things in new ways, and for trying out new things that could not previously be done as well or at all. That is the essence of Spacelab as it follows a proven route to innovation and progress.

 


Orbital inclinations and launch azimuths.

Orbital inclinations and launch azimuths.


Interior view of long module (engineering model), outfitted with experiment racks and other systems, during test at Spacelab's prime contractor, ERNO, in Bremen, West Germany.

Interior view of long module (engineering model), outfitted with experiment racks and other systems, during test at Spacelab's prime contractor, ERNO, in Bremen, West Germany.


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