How Astronauts Work

An astronaut is a person trained to pilot a spacecraft, travel in a spacecraft or work in space. The word first appeared in the English language in 1929, probably in science fiction, but it wasn't commonly used until December 1958. That's when the newly formed National Aeronautics and Space Administration (NASA) adopted the word "astronaut" as the name for the men (and eventually women) it would train to compete in the space race.

According to Allen O. Gamble, manpower director at NASA from 1958 to 1964, astronaut was not NASA's first choice. Program officials preferred Mercury, in reference to the messenger of the Roman gods, but the name had already been adopted for the first American manned spaceflight program. Gamble and his colleagues continued to brainstorm, and his own words capture the thought process they used:

With our best name so far already taken, out came the dictionaries and thesauruses. Someone found that the term aeronaut, referring to those who ride in balloons and other lighter-than-air vehicles, was derived from "sailor in the air." From this we arrived at astronaut, meaning "sailor among the stars."

The Soviet space agency came up with a similar term -- cosmonaut -- at about the same time. In many ways, this game of vocabulary was as much a part of the space race as anything else. Nikita Khrushchev, the Soviet premier at the time, knew the power of propaganda better than anyone, so he wanted a name that was both descriptive and inspirational. Some argue that cosmonaut, which means "sailor of the universe," is better than astronaut because humans have not actually traveled to the stars. Still, the name seemed right to NASA, and it stuck. Today, the two words are essentially synonymous in terms of what they imply about training and duties.

Although most people think of the U.S. or Russia when it comes to space and spacefarers, China has also successfully launched manned spacecraft. And several countries have contributed personnel to assist the U.S., Russia and China in their space programs. Westerners refer to Chinese astronauts as taikonauts, after tai kong, which means "great emptiness." In China, people refer to astronauts as yu háng yuán. And the French use the term astronaute or the more old-fashioned spationaute.

In the 1960s, the term astronaut was used briefly outside of NASA. The Department of Defense awarded the rating of astronaut to military and civilian pilots who flew aircraft higher than 50 miles (81 kilometers). Seven pilots received this rating for flights in the X-15 rocket plane, a craft that was launched from a B-52 aircraft at about 45,000 feet (13,716 meters) and attained speeds near 500 miles per hour (805 kilometers per hour). The X-15 contributed to the development of the Mercury, Gemini and Apollo piloted spaceflight programs as well as the space shuttle program. It also contributed Neil Armstrong, who would go on to become the first human to walk on the moon. The program's final flight was Oct. 24, 1968.

So how does NASA determine who gets to be an astronaut?

Today, the process for recruiting astronauts is streamlined and efficient. But when NASA set out to recruit the very first astronauts in 1958, it was entering unknown territory. One of the big problems had to do with defining an astronaut's role. In early job descriptions, astronauts were nothing more than observers who would view and document what was happening. It quickly became apparent, however, that human interaction would be required. Based on this, NASA decided it needed military pilots.

This was a logical decision considering the U.S. military's involvement with missiles and rocket planes in the aftermath of World War II. In 1946, the U.S. Army Air Force (as it was then known) and the National Advisory Committee for Aeronautics (NACA, the forerunner of NASA) placed an order with Bell Aircraft to produce three rocket planes. Eventually, testing of these aircraft was turned over to the U.S. Air Force, which had become a separate branch of the military as part of the National Security Act of 1947. On Oct. 14, 1947, Chuck Yeager

, an Air Force test pilot, broke the sound barrier in an X-1 rocket plane flying over Victorville, Calif. Although Yeager himself didn't become part of the Mercury manned spaceflight program, he served as a prototype for the kind of person NASA felt could succeed as an astronaut.

By the end of 1958, NASA finally settled on a list of qualifications for astronauts in the Mercury program. Each candidate had to:

NASA's astronaut selection committee sifted through the records of 508 servicemen throughout January 1959. About 100 of these were contacted for interviews and written tests, and 32 emerged as final candidates. A battery of medical testing cut the group to 18 and, finally, seven were chosen as the first astronauts. Three were from the Navy, three from the Air Force, and one from the Marines. The group became known as the "Original Seven" or the "Mercury 7" and included:

The Soviet Union began a similar selection process in August 1959 for its first group of cosmonauts. The Soviet Space Agency also turned to jet pilots as a source of candidates, and selection teams visited air bases throughout the country. A field of approximately 3,000 interviewees was narrowed down to 102 potential cosmonauts, who endured extensive and sometimes harrowing tests. By May 1960, with its training facility at Star City complete, the Soviet Union announced its first group of cosmonauts:

*Eventually replaced by Valery Bykovsky and Grigori Nelyubov

As NASA learned more about what it means to be an astronaut, its requirements began to change. Learn more about today's recruiting guidelines on the next page.

Over time, NASA missions evolved and so, too, did the qualifications for becoming an astronaut. By 1964, emphasis had shifted away from flight experience and toward superior academic achievement. The first scientist-astronauts joined the program in 1965 to deepen knowledge of geology, astronomy, physics and biochemistry. This new breed of astronaut, however, was expected to endure the same rigors of training and to become proficient in spacecraft operations. The first five scientist-astronauts were Joe Kerwin, Curt Michel, Owen Garriott, Ed Gibson and Jack Schmitt.

Today, NASA selects two kinds of astronauts for space flights -- pilot astronauts and mission specialist astronauts. Pilot astronauts command and pilot spacecraft and could command, in the near future, vessels that travel to Mars or back to the moon. Mission specialist astronauts work with pilots to maintain spacecraft and equipment, conduct experiments and launch satellites. Mission specialists may be engineers, scientists or physicians. NASA has also introduced mission specialist educator astronauts. Educator astronauts go through the same training as any other astronaut and, by traveling into space, inspire students to join the U.S. space program or to consider careers in math, science, engineering and technology.

There are two kinds of astronauts that fall outside NASA's standard recruitment procedures. International astronauts are those individuals from international space agencies who have trained at Johnson Space Center and serve as mission specialists. International astronauts come from four agencies that have an agreement with NASA: the European Space Agency (ESA), the Japan Aerospace Exploration Agency (JAXA), the Brazilian Space Agency (AEB) and the Canadian Space Agency (CSA). Payload specialists are scientists who work for the owner of the payload (usually a private company or university) and carry out experiments involving the payload. As such, they are not NASA employees, but NASA must approve their appointment.

Both civilian and military personnel can apply to become what NASA calls astronaut candidates. All astronaut candidates must be U.S. citizens and must have bachelor's degrees from accredited institutions in engineering, biological science, physical science or mathematics. All candidates must also be able to pass the NASA long-duration space flight physical, which has minimum requirements for visual acuity, blood pressure and standing height. Other requirements are based on the astronaut position, as outlined below:

Anyone interested in becoming an astronaut candidate must submit an appropriate application. Applications are screened, and those under consideration are invited to a weeklong process of personal interviews, medical screening and orientation. Selected applicants are assigned to the Astronaut Office at the Johnson Space Center in Houston, Texas, where training is held.

Once someone is selected to go into space, they have to get ready. How does NASA prepare its candidates for duty?

Applicants accepted as astronaut candidates report to Houston, Texas, the site of NASA's primary astronaut training facility. Known today as the Johnson Space Center (JSC), the facility actually began in 1961 as the Manned Spacecraft Center. In 1973, its name was changed to honor former president and Texas native Lyndon B. Johnson, who died that January. The JSC played a pivotal role in the Gemini, Apollo, Skylab, space shuttle and International Space Station programs. Over its nearly 50-year history, JSC has trained more than 300 U.S. astronauts and 50 astronauts from other countries. The training process used today is the culmination of this considerable experience.

The first phase starts with two years of basic training. Much of this training takes place in the classroom, where astronaut candidates learn about vehicle and space station systems. They also study key disciplines -- including earth sciences, meteorology, space science and engineering -- that may prove helpful in their work in space. Outside the classroom, astronaut candidates must complete military water- and land-survival training to prepare for an unplanned landing back on Earth. This survival training requires that they become scuba qualified and pass a swimming test in their first month. They must swim three lengths of a 25-meter (82-foot) pool without stopping, and then swim three lengths of the pool in a flight suit and tennis shoes with no time limit. They must also tread water continuously for 10 minutes while wearing a flight suit.

Once the basic training period is complete, candidates may be selected to become astronauts. You might think this is the end of training, but it's really just the beginning of the second phase. In this phase, astronaut trainees are grouped with experienced astronauts, who serve as mentors to share knowledge and experience. The ultimate goal of this mentoring relationship is to make sure each trainee is proficient in all activities related to pre-launch, launch, orbit, entry and landing.

Finally, astronauts receive their mission and crew assignments, entering what is known as the advanced mission training phase. In this final 10-month training period, astronauts focus on activities, exercises and experiments specific to their mission. For example, astronauts assigned to the STS-61 mission (Space Shuttle Endeavor, December 1993) were tasked with fixing the optics of the Hubble Space Telescope. Therefore, their training involved working with a full-sized model of the telescope in the Neutral Buoyancy Simulator at the Marshall Space Flight Center in Huntsville, Ala. The crew also trained at the Goddard Space Flight Center in Greenbelt, Md., where they familiarized themselves with the power tools and other special devices they would use during the mission.

As the STS-61 mission clearly demonstrates, a variety of simulators and facilities are needed to prepare astronauts for their work in space. JSC operates another neutral buoyancy simulator -- the Neutral Buoyancy Laboratory, or NBL -- to simulate weightlessness on Earth. The NBL is housed within the Sonny Carter Training Facility and, at 200 feet (61 m) long and 40 feet (12 m) deep, holds 6.2 million gallons (23.5 million liters) of water. Deep within the pool, astronauts train for spacewalks, spending approximately 10 hours under water for every hour they spend walking in space.

Since the end of the U.S. space shuttle program, more and more Americans train at Star City, a cosmonaut training facility near Moscow. Here, space-bound trainees receive hundreds of hours of training to help them tackle both routine procedures and surprise circumstances so that they can operate the Soyuz craft in any situation.

The variety of challenges faced by astronauts requires many different training environments. Learn more on the next page.

Astronauts have to be prepared both for general space travel and for their specific mission. To get them ready, NASA has a variety of environments for astronaut training.

Some training facilities and simulators include:

At the end of the advanced mission training phase, an astronaut is finally ready to carry out his or her assigned mission.

Every trip into space is different, but to get a feel for what it's like to work and live as an astronaut, let's look at a typical mission involving a Soyuz launch to the International Space Station (ISS).

The Soyuz rockets, which have changed very little since their original design four decades ago, launch from Baikonur Cosmodrome in Kazakhstan. The Russians have launched Soyuz rockets more than 1,500 times in the history of their space program, making this model one of the most used and most reliable in the history of space travel.

Engineers move the rocket by rail to the launch site two days before liftoff. There, they erect the rocket. At the launch pad, the craft, roughly 50 meters (164 feet) in length, is secured with three large arms that make sure the rocket is pointed skyward. These arms will fall away as the rocket pushes away from the ground.

Then the launch team performs a rehearsal. This practice run engages all mechanical and electrical systems to ensure that they are operating correctly.

With their long days of training finally complete, the astronauts enter the Soyuz crew capsule 2.5 hours before liftoff. They work in collaboration with ground controllers to prepare the rocket for its final launch sequence.

In only 45 seconds, the rocket hits an altitude of 11 kilometers (6.8 miles) and a speed of 1,640 kilometers (1,020 miles) per hour. After two minutes of flight time, the rocket is 40 kilometers (25 miles) high.

At this point, the crew tower disconnects from the main rocket body. The second stage of the rocket, however, continues to fire, subjecting those onboard to gravitational forces three times stronger than those on Earth. From a physical standpoint, this part of the journey is by far the most arduous.

Five minutes after launch, the craft is 170 kilometers (106 miles) above Earth. Then, the second stage of the rocket separates, and the third-stage rocket takes over propulsion duties. The ship is moving at more than 13,000 kilometers (8,000 miles) per hour.

Nine minutes following launch, the third stage of the engine stops firing and the orbital module separates from the rocket, at an altitude of nearly 220 kilometers (137 miles). The module's communication antennas and solar arrays unfurl, and the craft begins its approach to the ISS.

The rendezvous and docking procedures are fully automated. In case of emergency, though, the astronauts can interrupt this process and take control. It usually takes about two days from launch for the Soyuz capsule to reach the ISS, but recently Russian engineers have altered launch trajectories so that docking can begin in as little as six hours from launch.

Because of zero gravity (or microgravity, to be more precise), working in space is quite different from working on Earth. Astronauts must get used to being weightless, which causes bone and muscle deterioration and requires that all loose items -- including sleeping astronauts -- be tied down. Eating, drinking and using the bathroom are especially challenging activities for astronauts in orbit. Over the years, NASA has designed ingenious solutions that make living in space as comfortable as possible.

While in orbit, astronauts spend most of their time in the relatively safe confines of the craft or space station. Many missions, however, require a spacewalk, perhaps to deploy a satellite or make repairs. During a spacewalk, an astronaut must wear a space suit -- what NASA calls an extravehicular mobility unit (EMU) -- to protect and sustain him or her in the vacuum of outer space. Each EMU has a hard upper torso, a lower torso assembly and legs.

A portable life support system, or PLSS, integrates fully with the suit and is worn like a backpack. The weight of the EMU-PLSS assembly is considerable. The suit itself weighs about 110 pounds (50 kilograms), and the PLSS about 310 pounds (141 kilograms). For this reason, NASA designed EMUs for work in weightless conditions only, where the weight of the suit itself is unimportant. The Apollo suit, by comparison, was much different. Including the life support backpack, the Apollo suit weighed about 180 pounds (82 kilograms).

Most space stations missions last two to three weeks, but longer-duration missions may run as long as half a year. Usually, one astronaut on the Soyuz will trade places with one of the astronauts on the space station at the end of the mission. Then it's back to Earth.

Civilian astronauts are expected to remain with NASA for at least five years and, during this tenure, are employees of the federal government. Advancement for most workers in the federal government is based on a system of occupational pay levels, or "grades." A general schedule, or GS, determines the salaries for 15 grades. Workers typically enter the federal civil service at the starting grade for an occupation and begin a career ladder of promotions until they reach the full-performance grade for that occupation. The pay grades for civilian astronauts are GS-11 through GS-14, based on academic achievements and experience. Currently, a GS-11 astronaut starts at $64,724 per year; a GS-14 astronaut can earn up to $141,715 in annual salary [source: NASA].

Civilian astronauts may choose from a number of health plans and life insurance options; premium payments for these policies are partially offset by the government. Like all civil servants, astronauts hired after Jan. 1, 1984 participate in the Federal Employees Retirement System (FERS), a three-tiered retirement plan including Social Security, a pension plan and an optional Thrift Savings Plan.

Military astronauts are detailed to NASA for a specified tour of duty. They remain in active duty and receive their military pay, benefits and leave.

The space shuttle program was retired in 2011, leaving American astronauts looking for a new ride into space. These days, NASA is teaming with other space agencies to develop the Orion Multi-Purpose Crew Vehicle (MPCV). This craft could carry astronauts to the ISS, the moon, asteroids and even Mars. But the first manned flight won't happen until at least 2020, provided the program overcomes inevitable technical and budgetary challenges.

These kinds of slow-moving government-sponsored programs may eventually go by the wayside. Currently, commercial space flight is quickly gaining momentum, thanks in large part to some adventurous entrepreneurs and the maturation of spaceflight technologies.

With the development of spaceline companies such as Virgin Galactic XCOR, Blue Origin and others, anyone with enough cash can travel into space. This has led to an interesting semantic dilemma: What do you call a non-professional spacefarer? NASA refers to such people as spaceflight participants. Other companies call them space tourists. But what about the pilots of these spaceliners, who are neither employees of NASA nor nonprofessional passengers? In many circles, these new pilots are being called commercial astronauts.

Training for Virgin Galactic space tourists is minimal when compared to that of full-time astronauts. For a roughly two-and-a-half hour trip, these tourists will complete only two or three days of training. That includes, of course, a thorough medical checkup.

In lieu of any specialized expertise, what these tourists really need is cash -- a lot of it. To buy a ticket aboard a Virgin Galactic flight, you need $250,000. And even at that price, you'll have to wait in line. There are hundreds of paying customers already queued up for the first round of flights, which, as of summer 2013, are expected to begin in 2014.

The experience will be expensive and short-lived, but it will also be intense. Tourists will reach altitudes of 361,000 feet (110 kilometers) and experience about four minutes of microgravity, which is basically the same as a zero-gravity environment, meaning they can float about the cabin of the ship [source: Messier].

Although these tourists definitely don't qualify as astronauts, their presence in space signals a shift in the accessibility of space travel. Earth's orbit is no longer a realm exclusive to large government agencies. Now, companies of all types can literally reach for the stars.

Today's space race doesn't depend quite so much on national pride and government coffers. Instead, it's all about corporate money. And as it turns out, private companies have more money to blow on space ventures than most governments on Earth.

These companies, such as Virgin Galactic, SpaceX, XCOR and Blue Origin, want a slice of the space tourism pie as we mentioned earlier, but they offer commercial and scientific services, too. Such companies have access to systems that can put satellites into orbit and even dock with the ISS. SpaceX docked its Dragon spacecraft to the ISS in May 2012.

NASA does not see these companies as threats to its future. Instead, NASA is switching roles, morphing into an organization that enables and informs private companies as they spread their wings.

In that sense, the future of space travel may well be driven by corporations seeking profits. They'll charge other companies for space transportation and for rides to the ISS, the moon or maybe even Mars. They'll mine for minerals and elements on asteroids, the moon and possibly other planets. Because they're private companies, they'll be free to spend as much as they want to on these missions without backlash from the tax-paying public. And they'll be free of many of the constraints of government bureaucracy, too.

Not all space travel is directly profit-driven, though. A not-for-profit organization called Mars One is seeking to send colonists on a one-way trip to the red planet, with the intention of starting the first human settlements. Mars One is also planning on reality programming around the selection of the astronauts and the mission, including the opportunity for a viewing audience to select mission participants, to bring in broadcasting and sponsorship income to fund this endeavor. As of summer 2013, the company is pulling together the technical aspects of the mission, which is slated for 2023. It is also culling a list of tens of thousands of volunteers down to a total of 16 people, who will receive seven years of extensive training to (hopefully) survive their trip and begin their lives anew on another planet.

These people would be the ultimate pioneers, the first of their species to leave planet Earth permanently. It's bold missions like this that continue to stretch the meaning and symbolism of the word "astronaut." Although the original space race may have ended decades ago, we humans are still just at the beginning of what could be the most important chapters ever in the history of space exploration.