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Jupiter Orbit Probe
The first telescope was built by Galileo in 1608. His telescope used two lenses to make distant objects appear both nearer and larger. Telescopes that use lenses to bend light are called refracting telescopes, or refractors (Figure below). The earliest telescopes were all refractors. Many amateur astronomers still use refractors today. Refractors are good for viewing details within our solar system. Craters on the surface of Earth’s Moon or the rings around Saturn are two such details. -
Galileo’s Observations
In 1610, Galileo looked at the night sky through the first telescope. This tool allowed him to make the following discoveries (among others):
There are more stars in the night sky than the unaided eye can see.
The band of light called the Milky Way consists of many stars.
The Moon has craters (see Figure below).
Venus has phases like the Moon.
Jupiter has moons orbiting around it.
There are dark spots that move across the surface of the Sun. -
reflecting telescope
Around 1670, Sir Isaac Newton built a different kind of telescope. Newton's telescope used curved mirrors instead of lenses to focus light. This type of telescope is called a reflecting telescope, or reflector (see Figure below). The mirrors in a reflecting telescope are much lighter than the heavy glass lenses in a refractor. This is important because a refracting telescope must be much stronger to support the heavy glass. -
Publication of Principia
The English astronomer Sir Isaac Newton publishes the Philosophae Naturalis Principia Mathematica. This three-volume work outlines Newton's three laws of motion as well as his law of universal gravitation and a derivation of Kepler's laws for the motion of the planets. The Principia is considered by many to be one of the most important scientific works ever written. -
First Man in Space
Russian Cosmonaut Yuri Alekseyevich Gagarin became the first human to venture into space. The Vostok 1 spacecraft made one complete orbit around Earth in 108 minutes, and reached altitudes of 112 to 203 miles. The flight lasted only one hour and 48 minutes. -
First American in Orbit
Astronaut John H. Glenn was launched into orbit aboard an Atlas D rocket, where he became the first American to orbit the Earth. Glenn made a total of 3 complete orbits, and the flight time was 4 hours and 56 minutes. -
First Space Walk
Commander Pavel I. Belyayeu and Pilot Alexei A. Leonov into Earth’s orbit were launched into orbit aboard Voskhod 2. Alexei Leonov performed the first, tethered space walk outside of his spacecraft while in Earth’s orbit. This historic venture into space lasted a mere 12 minutes. -
First American Spacecraft on the Moon
Surveyor 1 became the first American spacecraft to soft-land on the Moon. After a journey of 63 hours and 36 minutes, Surveyor 1 successfully landed only 9 miles off its target in the Oceanus Procellarum. The spacecraft transmitted more than 11,000 high-resolution photographs before its energy sources were depleted. -
First Manned Apollo Mission
Apollo 7 is the first manned Apollo mission into space with Walter M. Schirra, Jr., Donn F. Eisele, and Walter Cunningham. It makes 163 orbits of the Earth during 10 Days, 20 minutes. The test flight checks life-support, propulsion, and control systems for the new Apollo spacecraft. -
First Space Shuttle Launch
The first manned mission of the Space Transportation System (STS-1), Columbia, is launched. This mission, as well as the next three, will be a test flight to try out the spacecraft's systems. -
Voyager 2 Arrives at Saturn
The Voyager 2 spacecraft arrives at Saturn and begins sending back images of the planet and its moons. -
First Venus Soil Samples
The Soviet Venera 13 spacecraft lands on the planet Venus and provides the first scientific analysis of the Venusian soil. -
Space Shuttle Challenger Tragedy
The space shuttle Challenger explodes shortly after liftoff of mission STS-51L, resulting in the loss of the spacecraft and her seven-member crew. The accident seems especially tragic because of Christa McAuliffe, the first civilian to fly into space. She is part of the Teacher in Space program and was to hold a number of classes for school children while in orbit. The accident is caused by unusually cold temperatures and a faulty O-ring seal in one of the solid rocket boosters. -
Goddard's Rocket Patents
U.S. rocket scientist Robert H. Goddard receives two landmark patents for rockets. The first described a multi-stage rocket and the second described a rocket fueled with gasoline and liquid nitrous oxide. These two patents would become major milestones in the history of rocketry. -
The Hubble Space Telescope
The Hubble Space Telescope is the best known space telescope. Hubble is shown in Figure below. Hubble began operations in 1994. Since then it has provided huge amounts of data. The telescope has helped astronomers answer many of the biggest questions in astronomy. The National Aeronautics and Space Administration (NASA) has placed three other major space telescopes in orbit. Each uses a different part of the electromagnetic spectrum. The James Webb Space Telescope will launch in 2014.
