Space Travel
You’re strapped into a seat. You hear a loud roar. Rocket engines fire and lift you into the sky. The rocket goes faster and faster, pushing you harder and harder against your seat. Suddenly, everything gets quiet. The engines stop. You take off your seat belt and start to float around. You are almost weightless. This is what space travel feels like.
GETTING INTO SPACE
Since ancient times, people have dreamed of leaving Earth and exploring other worlds. But gravity holds everything on the ground. Gravity is a pulling force between two objects. Earth is a very large object, and its gravity is strong. Even airplanes that fly thousands of feet above Earth can’t leave our atmosphere and go into space. Scientists and engineers had to make a force much greater than gravity to travel to outer space.
Finally, the dream came true. Engineers built rockets powerful enough to lift a rocket into space. In 1957, scientists from the Union of Soviet Socialist Republics (USSR) sent the first artificial satellite, Sputnik 1, into space. The United States soon sent an artificial satellite, Explorer 1, into space as well. The Space Age had begun.
The first spacecraft just orbited (went around) Earth. There were no humans on these spacecraft. Then scientists sent robot spacecraft to the Moon. The spaceships carried cameras that took pictures of the Moon’s surface. Some robot spacecraft even landed on the Moon.
The first person went into space in 1961. Soviet cosmonauts and American astronauts made several trips into orbit around Earth. The next goal was to send people to the Moon.
HEADING FOR THE MOON
After the Space Age began, engineers worked hard to figure out how to send people to the Moon. They made controls for steering spacecraft. They made spacesuits to allow astronauts to breathe and keep them safe from heat, cold, and harmful rays.
Engineers made special rocket ships for taking astronauts to the Moon. They named this series of spacecraft Apollo. An Apollo spacecraft held three astronauts. It also carried a smaller landing ship that looked sort of like a spider.
LANDING ON THE MOON
In July 1969, three astronauts in Apollo 11 headed for the Moon. On July 20, they made history. Astronauts Neil Armstrong and Buzz Aldrin climbed into the landing module, which was named Eagle. They went down to the Moon. The spiderlike legs of the lander dug into the Moon’s surface. Armstrong radioed back to Earth, “The Eagle has landed.” When he stepped on the Moon, Armstrong said, “That’s one small step for man, one giant leap for mankind.”
Astronauts in other Apollo spacecraft landed on the Moon five more times. Astronauts in spacesuits walked around on the Moon. They rode around in a kind of car called a lunar rover. All the astronauts brought back moon rocks and soil for scientists to study.
VISITING OTHER PLANETS?
Astronauts haven’t yet visited another planet. Robot spacecraft, also known as probes, have journeyed to all the planets except Pluto. These space probes carried cameras and took pictures of the planets. They studied gases around the planets. They can send these pictures and other information back to Earth by using special radio equipment.
Some of the space probes fly quickly past other planets. Voyagers 1 and 2 took off in 1977 to fly by Jupiter, Saturn, Uranus, and Neptune. After zooming by these planets, the Voyager probes headed out of the solar system. They continued to explore the space between the stars.
Some probes go into orbit around a planet. Some also drop landers on these planets. Several Soviet probes dropped landers on Venus. An American probe dropped a lander on Jupiter. More probes and landers continue to be sent, designed to explore other planets.
EXPLORING MARS
Of all the planets in the solar system, Mars is the most similar to Earth. Beginning in the 1960s, many robot spacecraft visited Mars. The Viking mission in 1975 was the first probe to safely land on Mars. A camera sent pictures of the surface to Earth. A robot arm scooped up soil.
The Mars Pathfinder spacecraft landed on Mars in 1997. It had a robot wagon called the Sojourner rover. The rover moved around on Mars, taking pictures and studying rocks. Other probes, landers, and rovers went on to study Mars.
Some people dream of astronauts someday landing on Mars. Other people say it would be best to send more robots. If astronauts do go to other planets, Mars would be the first one they visit.
THE SPACE SHUTTLE
In the 1970s, the United States developed a new kind of spacecraft called a shuttle. The shuttle blasts into space on big rockets. Unlike previous spacecraft, which used lander ships and could only be used once, the shuttle can land on Earth like an airplane and be used again. The first shuttle flew into space in 1981.
The shuttle has a big area called a cargo bay to hold large equipment. Astronauts on space shuttles launch satellites from the cargo bay. Some satellites study Earth from space, while others relay phone calls and other communications. Astronauts can also launch space telescopes from the shuttle.
LIVING IN SPACE
Space travel is hard on people’s bodies. Spending long amounts of time in space makes bones and muscles weak. It is hard to eat in space. It is hard to sleep and take showers.
Scientists use space stations to study how people can live and work in space. Space stations orbit around Earth. The Soviets sent up several space stations. The first, Salyut 1, was launched in 1971. The first U.S. space station, Skylab, was launched in 1973.
The most famous Soviet space station was Mir, which orbited Earth from 1986 to 2001. Astronauts from many different countries visited Mir. Many of them performed experiments on the space station. They learned many things about living and working in space.
In the late 1990s many nations started working together to build an International Space Station. The space shuttle carried parts for the station into space. Astronauts put the pieces together. The goal is to have people living and working in the space station all the time. Someday, maybe everyone who wants to will be able to travel into space.
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