EP-165 Spacelab

two illustrations of astronauts working aboard Spacelab.

"Spacelab circles our Earth in less than two hours. From its altitude national boundaries are unrecogniable. Its crew sees the Earth as one entirety. It is a small planet in the void of the Universe. One planet. One common home. It is a home which, with the help of space technology, has become surveyable in a single view, a home which we must be careful not to destroy. In fostering this awareness lies perhaps the truly epochal meaning of today's space technology.

"I wish this new space laboratory and its mother ship, the Shuttle, and their combined crews good flights in space and many happy returns to solid Earth."

- Dr. Wolfang Finke, Chief, Space and Aviation Research, West German Ministry for Research and Technology, December 4, 1981, at the presentation to NASA of the first Spacelab flight unit in Bremen, West Germany.


[27] CHAPTER THREE: Meet the Crew


Meet a new breed of space travelers! They are called payload specialists and they are the first non-career astronauts in space.

Typically they are scientists whose only reason for going on a space flight is to carry out some specific research in their own field of expertise.

Though they are considered to be members of the crew, they are not trained for and do not need to know how to operate the Shuttle, nor do they need to pass the stringent physical examinations required for career astronauts.

Payload specialists are the first passengers on manned space flights. Like riders on a bus or airliner, they leave the operation of the vehicle to professional drivers. While these payload specialists concern themselves with the conduct of their in-space scientific experiments, the navigation and other operational tasks for the Orbiter and Spacelab are handled by the career astronauts in the crew.

Payload specialists are new to NASA. They are making their first in-flight appearance aboard the first Spacelab flight- SL-1. That flight has two payload specialists in its six member crew. The other four crew members are the commander, the pilot, and two mission specialists.

Up to three payload specialists are expected to be on board future Spacelab flights, along with one or two mission specialists plus the commander and the pilot, for a total crew of six or seven members.

Mission specialists, also a new concept in U.S. space flights, made their first in-space appearance on the fifth Shuttle flight- STS-5- in November 1982. Since then two or three mission specialists have flown aboard each Shuttle mission.

Thus, personnel specialization is entering space in a big way. Though scientists and physicians have flown on U.S. spacecraft before and some astronauts have been trained for specialized tasks, in all of the first 36 U.S. manned space flights in the 22 years through November 1982 all crew members had been essentially cross-trained. Each crew member was fully prepared to take over the tasks of any of the others and, if need be, the operation of the vehicle. Scientists who were members of these crews all had joined the astronaut corps, had become career astronauts, and had undergone the same strenuous training as their test pilot colleagues for several years before making their first space flights.


Crew for the first Spacelab flight.

Crew for the first Spacelab flight.


[28] Assignments for Crew

In Spacelab flights, crew specialization calls for these assignments of responsibilities:

The commander and the pilot control the Orbiter and assure its operation according to the flight plan. They monitor its performance and steer and position it as necessary during launch, in orbit, and during reentry. The commander and pilot are career astronauts with several years of astronaut training and earlier experience as aviators and test pilots. The commander is responsible for the safe conduct of the mission and for the safe return of crew and craft.

Mission specialists are both professional scientists and career astronauts. Thus they are a link or bridge between the other crew members. Mission specialists have professional academic training as well as practical experience in at least one field of science or engineering. They have joined the astronaut corps.

The understand the Orbiter's as well as Spacelab's systems. They monitor, adjust, and service these systems. They include environmental control, communications, power generation and distribution, data processing and transmission, and even the mechanism for opening and closing the cargo bay doors. As their time permits, mission specialists work side by side with payload specialists in carrying out research. If work outside the Orbiter is required- for repairs or for the conduct of a scientific experiment- mission specialists are trained and equipped for space walks, formally known as extravehicular activities (EVAs). Thus it can be said that mission specialists combine the functions of resident maintenance engineers, In-space counterparts of flight engineers in aircraft, and fully qualified scientists.

Payload specialists are professional scientists or engineers whose only assignment on a space flight is to carry out scientific and technological experiments. Their specific training for a space flight is usually limited to a short period of learning how to live and work- how to move around, prepare food, eat, and use faucets and sanitary facilities- in weightlessness. They are kept free from routine operational duties. They can thus apply their attention to monitoring scientific research instruments, to observations, and to using their scientific experience and judgment for the accommodation and adjustment of instruments to unexpected conditions.

After completion of a flight, payload specialists return to their careers at research laboratories while the other crew members continue their training and preparations for another flight.


Crew Concepts Changing

The introduction of mission specialists and payload specialists is fundamentally altering troth the composition and the public's image of U.S. space flight crews. The public's perception is changing as the Shuttle becomes a routine, operational space transportation system and Spacelab also becomes operational. The 22-year male monopoly in U.S. manned space flight is now history. Eight women have completed several years of astronaut training at the Johnson Space Center in Houston, Texas, and are available for assignment to space flight crews. One of these, Dr. Sally K. Ride, a former Stanford University physicist, became the first woman aboard an orbiting U.S. spacecraft as a mission specialist on the seventh Shuttle flight (STS-7) in June 1983.

What a typical crew is like- and the diversity of backgrounds represented within it- is best illustrated by a closeup look at the six people assigned to the first Spacelab mission, designated SL-1. Because it also is the ninth flight for the Shuttle- the Space Transportation System (STS)- the flight is also designated as STS-9.

In terms of the combined professional experience of its crew (not to mention the quality of its research instruments) STS-9/SL-1 could well become the envy of many research laboratories on Earth. In the six-man crew are scientists, engineers, and veteran pilots. Each of the six has a background in a different specialty.

The crew for Spacelab 1:

Commander: John W. Young, veteran astronaut

Pilot: Brewster H. Shaw, Jr., veteran jet pilot

Mission Specialist: Dr. Owen K. Garriott, electrical engineer

Mission Specialist: Dr. Robert A.R. Parker, astronomer

Payload Specialist: Dr. Byron K. Lichtenberg, MIT biomedical engineer

Payload Specialist: Dr. Ulf Merbold, West German physicist



Spacelab-1 crew: Commander John W. Young; Pilot Brewster H. Shaw, Jr.; Mission Specialist Dr. Owen K. Garriott; Mission Specialist Dr. Robert A. R. Parker; Payload Specialist Dr. Byron K. Lichtenberg; Payload Specialist Dr. Ulf Merbold.

Spacelab-1 crew: Commander John W. Young; Pilot Brewster H. Shaw, Jr.; Mission Specialist Dr. Owen K. Garriott; Mission Specialist Dr. Robert A. R. Parker; Payload Specialist Dr. Byron K. Lichtenberg; Payload Specialist Dr. Ulf Merbold.

©National Geographic Society Painting by Roy Andersen.


The first total- all career astronauts- have spent a combined total of 60 years in training as full-time members of the astronaut corps. Two of them- Young and Garriott- have lived for a combined total of 12 weeks in space on earlier flights. Four of the six have earned Ph.D. degrees, each in a different field. All are married and all have children: Garriott has four, Shaw three, and the others two each, for a combined total of fifteen children, ranging in age from 7 to 28 years.


The Commander

John W. Young at age 53 easily qualifies for the title of the world's most experienced space traveler. He has been a full-time astronaut for 21 years. He has flown in a record five space flights- in three of these as commander- in three generations of spacecraft, spending a total of 27 days in space. That total includes three days of living on the surface of the Moon.

STS-1 is Young's sixth flight into space, his fourth as commander, and the mission will make him the first person to fly a second time on three kinds of spacecraft. He was the commander of the Shuttle's first orbital flight, STS-1, April 12 to 14, 1981.

Born in San Francisco on September 24, 1930, Young grew up in Orlando, Florida, where his parents still live. He earned a bachelor of science degree with highest honors in aeronautical engineering from Georgia Institute of Technology in 1952. He joined the U.S. Navy and, as a Navy test pilot, set world time-to-climb records to 3,000 and 25,000-meter altitudes in 1962, just before he was selected as an astronaut in September of that same year.

He was on two separate orbital flights in the two-man Gemini spacecraft (Gemini 3 in 1965 and Gemini 10 as commander in 1966) and on two separate flights in the three-man Apollo- Apollo 10, which orbited the Moon 31 times in May 1969, and Apollo 16, which achieved landing on the Moon in April 1972. As commander of that last flight, Young and a colleague collected 90 kilograms (200 pounds) of Moon rocks during 20 hours of scientific explorations in which they walked and drove in the lunar roving vehicle for 43 kilometers (27 miles) through the rugged lunar highlands. Since January 1975, Young has been the chief of the Astronaut Office which schedules and coordinates all astronaut activities. This makes him director of all of NASA's six dozen astronauts at the Lyndon B. Johnson Space Center in Texas.


[30] The Pilot

Brewster H. .Shaw, Jr., 38, the STS-1 pilot who assists Young and alternates with him during shift changes in the Shuttle cockpit, is a U.S. Air Force test pilot and former test pilot instructor with more than 3,000 hours of flying time in more than 30 types of aircraft. He has been an astronaut since January 1978. STS-1 is his first space flight. A native of Michigan, he earned bachelor and master of science degrees in engineering mechanics from the University of Wisconsin at Madison in 1968 and 1969 before joining the Air Force.


Mission Specialist

Dr. Owen K. Garriott, 52, one of the two STS-1 mission specialists, is one of NASA's most experienced scientist-astronauts. Though stationed at the Johnson Space Center in Houston, Texas, as a full-time member of the astronaut corps for more than 18 years, he still retains his consulting professorship at Stanford University in California, where he taught electronics, electromagnetic theory, and ionospheric physics from 1961 until he became an astronaut in 1965. He has done extensive research in ionospheric physics- studies of the upper atmosphere- and has published a book and 30 scientific papers in this field.

Garriott lived in orbit continuously for 59 1/2 days from July 28 to September 25, 1973, as a member of the second three-man crew that occupied Skylab, the 100-ton U.S. orbital research space station. On that mission Garriott spent a total of 13 hours and 43 minutes working outside Skylab on three separate space walks.

A native of Enid, Oklahoma, where his parents still live, he earned a Bachelor of Science degree in electrical engineering from the University of Oklahoma in 1953. He received a master of Science degree in 1957 and a doctorate in electrical engineering in 1960, both from Stanford University. He served as an electronics officer in the U.S. Navy from 1953 to 1956, and has logged more than 3,900 hours piloting aircraft. He interrupted his astronaut activities, serving briefly as director of applications and assistant director for space science at the Johnson Space Center, before going into mission specialist training.


Mission Specialist

Dr. Robert A.R. Parker, 46, Garriott's colleague as STS-1 mission specialist, has also been a member of a college faculty. He was an associate professor of astronomy at the University of Wisconsin until his selection as an astronaut in 1967. Though he has been in training as an astronaut for 16 years, SL-1 is his first space flight. He grew up in Shrewsbury, Massachusetts, where his parents still live. He earned a bachelor's degree in astronomy and physics at Amherst College in 1958 and a doctorate in astronomy from the California Institute of Technology in 1962.


Veteran Scientist-Astronaut Dr. Owen K. Garriott is a mission specialist on the first Spacelab flight.

Veteran Scientist-Astronaut Dr. Owen K. Garriott is a mission specialist on the first Spacelab flight.


Payload Specialist

Dr. Byron K. Lichtenberg, 35, a researcher in biomedical engineering at the Massachusetts Institute of Technology (MIT), is the youngest member of the STS-1 crew. He is the first American to fly in an orbiting U.S. spacecraft who is not and never has been a [31] member of the astronaut corps. His name also goes into history as the first American scientist to carry out an experiment in space that he helped design and that he will help analyze and interpret as a member of a research team. In the past scientists instructed astronauts on how they wanted their experiments carried out so that the astronauts could do it for them.

Lichtenberg is a member of an MIT biomedical engineering research group tracing the causes of- and seeking ways to prevent- motion sickness. At the time of his selection for the STS-1 flight crew, Lichtenberg was participating with other...


Payload Specialist Dr. Byron Lichtenberg works on experiment racks inside long module during training at Marshall Space Flight Center Huntsville, Alabama.

Payload Specialist Dr. Byron Lichtenberg works on experiment racks inside long module during training at Marshall Space Flight Center Huntsville, Alabama.

Payload Specialist Dr. Byron Lichtenberg works on experiment racks inside long module during training at Marshall Space Flight Center Huntsville, Alabama.


...members of that research group in the design of an experiment for use in STS-1 for learning more about the workings of the gravity-sensitive mechanism the inner ear called the vestibular organ. This is the organ that helps us sense change of speed and direction of body movement even when our eves are closed. When the vestibular mechanism is disturbed by disease or unusual movements- such as in a boat or airplane- some people become seasick or airsick. In the absence of gravity several astronauts have complained about another variety of motion sickness known as space sickness. Lichtenberg is scheduled to carry out several experiments on himself and his fellow crew members in the absence of gravity in orbit. Lichtenberg, who w as born in Stroudsburg, Pennsylvania, in 1948, earned his bachelor of science degree in electrical engineering from Brown University in 1969, then served in the U.S. Air Force for four years until 1973, winning two Distinguished Flying Crosses during his tour of duty in Vietnam. He received his master's degree in mechanical engineering in 1975 and his doctor of science degree in biomedical engineering in 1979, both from MIT. He is the first American selected for travel on a U.S. spacecraft by a committee of the scientists whose experiments are aboard the flight (as explained later).


Payload Specialist Dr. Byron Lichtenberg practices a technological experiment in replica of Spacelab module.

Payload Specialist Dr. Byron Lichtenberg practices a technological experiment in replica of Spacelab module.


[32] Payload Specialist

Dr. Ulf Merbold, 42, a physicist specializing in metals research, is the first non-American to be launched into space aboard an American spacecraft.* A citizen of West Germany, he is a former staff member of the Max Planck Institute in Stuttgart, and an employee of the European Space Agency (ESA) while he is working on the STS-1 mission. He was selected by ESA as the SL-1 payload specialist representing European scientists.

Born in Greiz, Germany, in 1941, he was graduated in 1968 from Stuttgart University and received a doctorate in science there in 1978. He joined the Max Planck Institute for Metals Research on a scholarship in 1968 and later as a staff member.

The commander, the pilot, and the two mission specialists were selected from about 70 active members of the U.S. astronaut corps at the Johnson Space Center in Houston in the traditional way by NASA officials, who customarily assign astronauts to specific missions.

But selection of the two STS-1 flight payload specialists- Lichtenberg and Merbold- came about through an unprecedented procedure.


Scientists Choose Candidates

In May 1978 a committee composed of the U.S. members of the SL-1 Investigators....


The original five payload specialist candidates, selected from several thousand applicants, gather in front of a Spacelab table model in February 1982 as they begin intensive training.

The original five payload specialist candidates, selected from several thousand applicants, gather in front of a Spacelab table model in February 1982 as they begin intensive training. Since then, Dr. Byron K Lichtenberg (extreme right) of the United States and Dr. Ulf Merbold (second from left) of West Germany have been selected for the flight crew for the first Spacelab mission. Dr. Michael L. Lampton of the United States (center) and Dr. Wubbo Ockels (left) of the Netherlands are the alternates. Dr Claude Nicollier (second from right) of Switzerland is in training as a mission specialist at the Johnson Space Center in Houston.



[33] ...Working Group (IWG) met at the Marshall Space Flight Center in Huntsville, Alabama. It nominated two American payload specialist candidates: Lichtenberg and Dr. Michael L. Lampton of the University of California, Berkeley, whose research had encompassed space physics, X-ray and ultraviolet astronomy, and optical and electronics engineering.

The ESA selection process began in December 1977 when ESA in consultation with the European scientists who were then building SL-1 experiments announced the selection of three payload specialist candidates from more than 2,000 European applicants: Merbold; Dr. Wubbo Ockels, a nuclear physicist from the University of Groningen, the Netherlands; and Dr. Claude Nicollier, a Swiss astronomer.

The five began preparing for the mission by acquainting themselves with the experiments and with the Spacelab components and systems, all of which were under construction.

While Spacelab was being built in Europe, the Shuttle, being built in the United States, was encountering problems with the heat protective tiles that cover its underside and

with the performance of its revolutionary new rocket engines. These problems delayed the Shuttle's readiness for flight, giving the payload specialist candidates unexpected extra time for training. They also were able to return occasionally to their jobs at their laboratories for several weeks at a time between their payload specialist preparations. until their intensive full-time training began in January 1982.

Meanwhile, Nicollier was assigned by ESA to mission specialist training at the Johnson Space Center. Thus he was no longer a contender for the payload specialist assignments, leaving the European competition to Merbold and Ockels.

The four (Lichtenberg, Lampton, Merbold, and Ockels), together with the two mission specialists, traveled and met most of the more than 70 SL-1 principal investigators in the United States, Europe, and Japan. The!! learned from them the details of these experiments, how to operate and adjust them, and how to make corrections if necessary for almost every conceivable contingency.

Then the four payload specialists, together with the mission specialists, began training in the Spacelab Payload Crew Training Complex at the Marshall Space Flight Center. The model's interior closely resembles the interior of the SL-1 module. The candidates became acquainted with the experiment arrangements in the racks and the other module facilities. They practiced conducting experiments simultaneously and in prescribed sequences, simulating in-flight routines. Computer facilities simulated experiment results, and candidates practiced monitoring, interpreting, and responding to them.


Variety of Training Provided

In nonstop training sessions that kept the candidates inside the module more than 12 hours each day, they became accustomed to the SL-1 work routine, which calls for two 12 hour shifts so as to keep SL-1 in operation on a continuous 24-hour-a-day basis during the flight. On the mission either the commander or pilot is on duty on the flight deck at all times, and one mission specialist and one....


Payload Specialist Dr. Ulf Merbold trains himself for work with research instruments for first Spacelab flight.

Payload Specialist Dr. Ulf Merbold trains himself for work with research instruments for first Spacelab flight.


[34] ....payload specialist are on duty in either the module or on the flight deck, while the other three crew members sleep or relax until they take their turns on a 12-hour shift.

The payload crew (both mission and payload specialists) were taken on flights in KC-135 jet aircraft in which weightlessness is simulated for up to 30 seconds at a time by operating the craft in parabolic curves to create a situation resembling the sensation one feels for a few seconds in a very fast descending elevator. During such brief periods of weightlessness the candidates practiced eating, drinking, and using various utensils as they would later in the Orbiter and the Spacelab module. The payload and mission specialists trained in the Orbiter model at the Johnson Space Center to acquaint themselves with the Orbiter's flight and mid decks and to practice living in them.

On September 30 and October 1, 1982, the IWG held a historic meeting at the Marshall Center to review all science aspects of the STS-1 flight. But the end of that meeting the group had also made the crucial final selection of their own STS-1 in-flight representative. With the approval of NASA they had selected Lichtenberg for the prime crew and Lampton as the alternate for the STS-1 payload specialists positions. The alternate provides scientific support to the mission from the Payload Operations Control Center while the flight is in progress. Meanwhile Merbold was chosen by ESA for the prime and Ockels as the alternate.

Thus the researchers who designed and built the experiments, and who are to analyze the results, helped select from their peers the two in-flight specialists who are to be in charge of carrying out research in orbit.


Crew Can Total Seven

The STS-1 six-man crew will be exceeded soon. Crews of seven are expected to be assigned to some Spacelab flights.

On each of the two Shuttle flights preceding Spacelab-1- STS-7 and STS-8- a physician was added to the crews. As flight crews grow in numbers, the inclusion of a physician becomes logical to tend to the health of the crew, provide care in the event of illness or accident, carry out studies on the impact of prolonged weightlessness on the human system, and, particularly, to extend the continuing investigations of motion sickness to which SL-1 is expected to make major contributions.

Sending Ph.D.'s and physicians into space ceased long ago to be a novelty. Except for the very earliest manned space flights, such assignments have been common in the U.S. space program. The first American Ph.D. in space was Edwin E. ("Buzz") Aldrin, Jr., then 36, who made his first space flight in November 1966 aboard the Gemini 12. It was the last mission of the 10-flight series with the two-man Gemini spacecraft, and Aldrin, who had written his doctoral dissertation on orbital mechanics, made landmark contributions toward achieving that flight's objective of going into formation flight- rendezvous - with an unmanned orbiting Agena craft and then linking up- "docking"- with it. Aldrin was the second person in history- and the first Ph.D.- to walk on the Moon. He had earned his doctorate in astronautics at the Massachusetts Institute of Technology in 1963 and had been in the U.S. Air Force where he became a colonel.

The distinction of being the first working scientist to walk on the Moon went to Dr. Harrison H. Schmitt, then 37, who became the last of the 12 U.S. astronauts who visited the Moon. The Apollo 17 flight in which he participated in December 1972 ended the six flight series of Moon landing missions. Schmitt, who later served a term as a U.S. Senator from New Mexico ( 1977-1983 ), had received his doctorate in geology from Harvard University in 1964, a year before he became an astronaut. He had worked for the Norwegian Geological Survey in Oslo, Norway, and for the U.S. Geological Survey (USGS) in New Mexico, Montana, and Southwestern Alaska and also for the USGS Astrogeology Branch as a project chief for photo and telescopic mapping of the Moon. Mainly because of this last experience he had been assigned by the USGS- before he himself became an astronaut- as an instructor for Moon-bound astronauts preparing for geological field trips and the collection of geological samples.


Medical Specialist Flown

The first American physician in space was Dr. Joseph P. Kerwin, then 41, who was a member of the first of three crews who visited Skylab, the house-size, 100-ton U.S. space station.

He and two astronaut companions lived in that station in orbit for 28 days from May 25 [35] to June 22, 1973. Kerwin had been added to the Skylab crew because of the increasing awareness at that time of new opportunities for medical research in weightlessness which could contribute to the understanding of the human system on the Earth.

Skylab's roominess made possible thorough physical examinations of astronauts in orbit for the first time, and Dr. Kerwin took advantage of these opportunities to examine himself and his two astronaut colleagues in his studies of their physical responses to prolonged weightlessness.

Until that time the effects of weightlessness could be determined only from descriptions by! astronauts, from examinations of the crews immediately before and after a flight, and from some limited monitoring of certain body functions , such as the heartbeat, with tiny sensors taped to the chests of astronauts.

Kerwin and Schmitt had been among six scientists who joined the U.S. astronaut corps as a group in June 1965 to go into training as scientist-astronauts. Also among those six was Dr. Owen K. Garriott (who is mentioned earlier in the chapter), a member of the second Skylab crew in the mid-1970s and now a mission specialist in the STS -1 crew.


Weightlessness is achieved fo a few seconds inside a KC-135 aircraft flying in a parabolic curve.

Weightlessness is achieved for a few seconds inside a KC-135 aircraft flying in a parabolic curve. Spacelab-1 Payload Specialist Dr. Byron K. Lichtenberg (in green clothes at right with left hand to ceiling) and his alternate, Dr. Michael L. Lampton (in blue clothes at top center), together with a Johnson Space Center physician, Dr. Joseph Degicanni (center), practice moving around in weightlessness with the help of technicians as part of the training for Spacelab-1.


Science Specialists Needed

The selection of science specialists came as a result of an increasing realization at the time that the ranks of the early test-pilot astronauts would have to be augmented by experienced scientists if the research opportunities of the new system were to be fully exploited.

The new scientist-astronauts had to abandon their scientific positions to cuter full-time astronaut training at the Johnson Space Center. Each of them had to spend several years learning the operation and handling of spacecraft, and they had to share in spacecraft operational tasks and other in flight chores as full members of the flight crew. The full extent of the preflight training required of scientist-astronauts is illustrated by the fact that Kerwin and Garriott had been full-time astronauts for eight years and Schmitt for seven years before they made their first space flights.


Training Time Reduced

In contrast, today's Spacelab payload specialists need to undergo only a brief training period. They are not expected to give up or to be away for very long from their positions in their research centers during their temporary training and work on a flight crew. Though the STS-1 payload specialists, being the first, had a longer training period, the time for the preparation of future payload specialists is expected to shrink eventually to about 100 hours. This preparation period includes the time necessary for their familiarization with the instruments on their assigned missions. This abbreviated training is expected to make it possible for NASA to recruit distinguished investigators for work in space who would not be willing to relinquish or substantially interrupt their scientific career positions.

Spacelab is a machine entirely dependent on human know-how and human direction. Notwithstanding their sophisticated automatic systems, the Shuttle and Spacelab are built to carry human crews and to be operated by these crews. Beyond its sensitive observation instruments and its other advanced research apparatus, Spacelab's essential ingredients remain the intellect, judgment, and skills of the people who operate it. There is no substitute or near substitute for these qualities. Spacelab relies Completely upon human performance for its ultimate success. The most important system aboard Spacelab is its crew.

* Only once before have non-Americans been inside an orbiting US spacecraft, but they were neither launched in it nor did they return in it to Earth. That was on July 17 and 18, 1975, during the Apollo-Soyuz flight, when a U.S. Apollo with three U.S. astronauts linked in orbit with a Soviet Soyuz carrying two cosmonauts. The American and Soviet crews visited each other by passing through a tunnel connecting the joined craft. On that flight, Soviet cosmonauts Aleksey A. Leonov, and Valeriy N. Kubasov, each spent several hours inside the orbiting Apollo before they returned to their own craft and completed their flight in the Soyuz.