Astronaut

I

Introduction

Astronaut, crew member on piloted spaceflights. The term astronaut comes from the Latin words astrum (“star”) and nauta (“mariner”) and is used mostly in English-speaking countries. Russians who go into space are called cosmonauts. French space travelers are called spationauts. The International Astronomical Federation defines space travel as beginning 100 km (62 mi) above Earth, so some airplane pilots are considered astronauts. See Space Exploration.

Piloted spaceflight is an important aspect of space exploration. Humans in space can retrieve and repair satellites that might be useless otherwise. Studies of the effects of space on the human body have provided important medical knowledge for humans on Earth. Astronauts can perform experiments in space that machines cannot. Current piloted spaceflight may help scientists develop ways to allow humans to survive in space longer, which will be necessary if humans ever visit or colonize other planets.

Astronauts came into being in the late 1950s, when both the United States and the former Union of Soviet Socialist Republics (USSR) began piloted spaceflight programs. Both countries chose military pilots as the first astronauts. No one really knew what astronauts would be required to perform or how they would be required to behave, but it made sense to choose people with proven flying abilities and reliability in dangerous environments. Also, some of the earliest spacecraft were based on the high-performance aircraft that these pilots were accustomed to flying. Modern astronauts include scientists, engineers, medical doctors, and educators, as well as pilots.

II

Milestones

The journey of humans into space began with the launch of the first satellite—the Soviet Sputnik—in 1957. The USSR was also the first country to send a person, Yuri Gagarin, into space. Gagarin was the first human to orbit Earth, as well as the first person in space, when he flew aboard Vostok 1 in April 1961. The United States first sent a person, astronaut Alan B. Shepard, Jr., into space in May 1961. The first U.S. astronaut to orbit Earth was John H. Glenn, who made a three-orbit flight in February 1962. Soviet cosmonaut Valentina Tereshkova became the first woman to go into space in June 1963.

---

---

The first humans to set foot on the Moon were U.S. astronauts Neil Armstrong and Buzz Aldrin, who landed the lunar module of Apollo 11 on the surface of the Moon on July 20, 1969. When John Glenn flew aboard a space shuttle mission in 1998 at the age of 77 he became the oldest person ever to go into space. In 2004 Mike Melvill became the first person to pilot a privately owned spacecraft into orbit. In all, more than 400 people from more than 20 countries have flown in space.

Russian cosmonaut Valeriy Polyakov holds the record for spending the most consecutive days in space. He spent 438 days aboard the Mir space station in 1994 and 1995. Astronaut Shannon Lucid of the United States spent 188 days aboard Mir in 1996, giving her the U.S. record for long-duration spaceflight.

III

What Do Astronauts Do?

The very first astronauts were little more than human test subjects, but today’s astronauts are pilots, scientists, and engineers with active roles in many aspects of their missions. In the first ever piloted spaceflight, Vostok 1, cosmonaut Yuri Gagarin had little more to do than go along for the ride while a ground crew controlled the spacecraft by remote control. The instruments had an override code that Gagarin could have used if something went wrong, but he did not know the code before the flight. It was sealed in an envelope attached to the capsule’s wall. The first U.S. astronauts—those in the Mercury program—had some control over their spacecraft. Alan Shepard tested the manual controls of the Mercury capsule in space and manually fired the retrorockets that slowed the capsule enough to allow it to fall back to Earth. Gordon Cooper, the astronaut aboard the last Mercury flight, was forced to land his capsule manually when the automatic reentry system developed electrical problems.

As missions grew more complex, astronauts began to control more aspects of the mission. Cosmonauts and astronauts of the Soviet Voskhod and U.S. Gemini programs studied the effects of weightlessness, left the spacecraft in pressurized spacesuits to perform extravehicular activities (EVAs) or spacewalks, and guided their capsules close enough to other spacecraft to dock with them. During the Apollo program, astronauts spent days on the surface of the Moon exploring and performing experiments. Astronauts aboard the U.S. Skylab space station and the Soviet Salyut and Mir stations began to spend months in space at a time.

Astronauts who fly aboard the space shuttle or stay aboard the International Space Station often spend months or years developing their missions. Astronauts have significant roles in planning and carrying out scientific experiments and performing tasks while in space. The U.S. National Aeronautics and Space Administration (NASA) designates space shuttle astronauts as pilots, mission specialists, and payload specialists. Every space shuttle mission includes at least two pilots and at least two mission specialists.

Pilots can have one of two jobs on a mission: They can be the mission commander or the mission pilot. Commanders work with controllers on the ground to make all critical decisions during the mission. Commanders also fly the shuttle in space and during landing and can take over from the space shuttle’s computers at any time. They also monitor the shuttle’s key systems—such as guidance, navigation, and flight control—throughout the mission. The mission pilot acts as a backup to the commander. The pilot has the same training as, but usually less experience than, the commander.

Mission specialists are scientists and engineers who deal with the specific experiments and equipment onboard for the mission. They must have detailed knowledge of shuttle systems and of the equipment and objectives associated with that mission. Their duties in orbit may include leaving the spacecraft for spacewalks, operating the space shuttle’s robot arm (called the remote manipulator system), deploying satellites, and operating onboard experiments. On every space shuttle flight, one mission specialist acts as flight engineer during launch and landing to support the pilot. Two mission specialists in each mission are assigned emergency spacewalk duties, just in case the mission requires an unexpected spacewalk.

Payload specialists serve on some space shuttle missions. Payload specialists are not astronauts by profession, but receive months of space shuttle training before their mission. The science team for the mission selects its own payload specialists. Payload specialists work on specific experiments or equipment with which they have significant experience. Because payload specialists are more scientists or engineers than astronauts, they are able to provide greater expertise than a career astronaut could obtain in the 18 to 24 months before a mission. Often a mission specialist and a payload specialist will pair up during training and during the mission to create a team with extensive experience in both space shuttle and scientific systems.

Before the space shuttle Challenger exploded in 1986 (see Challenger Disaster), NASA allowed a few people who were neither scientists nor astronauts aboard the space shuttle as payload specialists. These included U.S. senator Jake Garn and teacher Christa McAuliffe. After the Challenger explosion, NASA began to require that payload specialists have more space shuttle training and extensive expertise in the mission’s scientific objectives.

All crew members usually share in space housekeeping duties such as meal preparation, cleaning, and stowing gear. Between spaceflights, astronauts support other space shuttle missions through jobs in Mission Control or at the launch site, by advising teams that are planning future payloads and missions, or by helping test future experiments and equipment.

Every operation during a flight is important and interesting, but many might be boring to an observer. Much of an astronaut’s job is entering computer instructions, preparing samples, making measurements, recording data, fixing what breaks, and adjusting the checklist when something unexpected happens. Sometimes astronauts retrieve or repair satellites, rendezvous or dock with other spacecraft, and do important emergency repairs. The adaptability of the human crew is crucial to the success of missions in which unexpected things happen.

IV

Astronaut Selection

The first American and Soviet astronauts were selected from the military only. As space travel has become more frequent and the goals of missions have become more diverse, astronaut selection has broadened to include scientists and other civilians.

	More from Encarta
	•  7 tips for funding an online degree •  How to succeed in the fashion industry without being a top designer •  Presidential Myths Quiz •  Coffee break: Recharge your brain