Since Yuri Gagarin became the first spaceman in 1961,
hundreds of space travellers, or astronauts (called cosmonauts if Russian),
have ventured into space. Experience has shown that humans can work well in
space both on board their spacecraft and outside on EVAs. In
space, astronauts’ bodies are constantly monitored, both to check their
health, and as part of the study of SPACE MEDICINE –
research into how the body is affected by weightless conditions.
On Earth, an astronaut practises for spacewalking in a water tank.
He wears a suit like a spacesuit, which is weighted so that it neither rises
nor sinks. Such neutral buoyancy (floating) conditions are similar to the state
of weightlessness that astronauts experience, and have to work in, while in
space.
Astronauts on today’s space flights eat a variety of foods.
Some are in their natural state, such as nuts and biscuits, and some are canned
or frozen. Other foods are dehydrated and need to be mixed with water before
eating. In the early days of space flight, astronauts ate nutritious but
unappetizing food pastes out of toothpaste-type tubes.
Up in orbit, astronauts sometimes have to work outside
their spacecraft. This extravehicular activity, or EVA, is popularly called
spacewalking. Russian cosmonaut Alexei Leonov and US astronaut Edward White
pioneered spacewalking in 1965. Today, astronauts go on EVAs to recover and
repair satellites and carry out construction work on the International Space
Station.
On shuttle mission STS-112 in October 2002, astronaut David Wolf
worked for over six hours to install equipment on the International Space
Station (ISS). He was helped by astronaut Piers J. Sellers. The main purpose of
this mission was to take up a new truss (beam) for the framework of the ISS. It
was then installed by the astronauts.
On the shuttle STS-109 servicing mission in March 2002, astronauts
installed a new power unit, a new camera, and new solar arrays on the Hubble
Space Telescope. On this mission, the astronauts clocked up a record 36 hours
spacewalking in five separate EVAs. This was the fourth shuttle mission
dedicated to servicing the Hubble telescope.
Because of the weightless environment, space flight
affects the human body in a number of ways. Muscles begin to waste away and
bones tend to lose mass and become more brittle. Exercise and a suitable diet
helps to combat these conditions on long space flights.
On shuttle mission STS-95 in 1998, John Glenn was fitted out with
instruments to monitor his sleep patterns. In 1962, Glenn became the first
American to orbit Earth. He joined the shuttle mission in 1998, aged 77, as
part of research into how weightlessness affects the aging body.
