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Launched from the space shuttle Discovery

in 1990, the Hubble Space Telescope (HST)

orbits about 600 km (370 miles)

above Earth. It sends back some

of the most detailed images of

the Universe ever seen.

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WHY ARE OBSERVATORIES LAUNCHED INTO SPACE?

Earth’s moving atmosphere bends and distorts the light from distant stars and

galaxies. In space, observatories can see far more clearly. They can also pick up

radiation (such as X-rays) that we can’t detect on Earth

because it is absorbed by molecules in the atmosphere.

Exploring the planets and other bodies in the Solar

System are interplanetary spacecraft. They carry

advanced cameras and other instruments to detect

radiation, magnetism, and tiny particles of matter.

A spacecraft launched to observe the Sun, stars, and remote galaxies is

called a space observatory. The. HUBBLE SPACE TELESCOPE was the first

really important space observatory.

WHERE HAVE INTERPLANETARY SPACECRAFT BEEN?

The first spacecraft were sent to explore the Moon,

then the nearest planets, Venus and Mars. Spacecraft

have now visited all the planets and explored moons,

comets, and asteroids. Some fly by their targets but

others go into orbit around them or even land.

A few release a separate. PROBE.

DATE MISSION TARGET

1959 Luna 2 First to photograph far side of Moon

1965 Mariner 4 First close-up images of another planet (Mars)

1973 Pioneer 10 First close-up of Jupiter

1976 Viking 1, 2 First to land on Mars

1986 Voyager 2 First to explore Uranus and Neptune

1986 Giotto First close encounter with a comet (Halley’s)

2000 NEAR First to land on an asteroid (Eros)

HOW DOES THE HST WORK?

The HST is a reflecting telescope – it uses mirrors

to gather and focus light. The focused light is fed to

electronic cameras and infrared detectors to create

images. The main sensors are CCDs (charge-coupled

devices), similar to the ones used in digital cameras.

WHAT IS THE HUYGENS PROBE?

The Cassini orbiter carried a probe called Huygens.

In 2005, Huygens parachuted down through the

atmosphere of Titan, Saturn’s largest moon, sending

back information as it fell to the surface.

INTERPLANETARY SPACECRAFT

Interplanetary Spacecraft

SPACE OBSERVATORIES

Space Observatories

A probe is a part of a larger spacecraft that

is released to drop into the atmosphere or

to the surface of a planet or a moon.

HUBBLE SPACE TELESCOPE

FIND OUT MORE. Astronomy 11 • Light 178–179 • Observatories 12

PROBES

1 HUBBLE’S VIEW

This Hubble image shows a mass

of gas and dust called the Cone

Nebula. It is silhouetted by intense

light from hot stars behind.

4 CASSINI SPACECRAFT

Launched in 1997, the Cassini

spacecraft went into orbit around

Saturn in 2004 to explore the

planet and its moons.

1 VIKING LANDER ON MARS

Two landers touched down on

Mars in 1976, taking photos and

monitoring the weather.

Radio antenna sends

information to Earth and

receives instructions

Aft (rear) shroud

houses cameras

Sunshade

protects the

telescope from

direct sunlight

Dish antenna

directs radio

communications

towards Earth

Gold foil

protects

instruments

and electronics

Solar array

provides

electrical

power

KEY INTERPLANETARY MISSIONS

Body tube

houses reflecting

telescope

Rocket motor

propels spacecraft

FIND OUT MORE. Mars 19 • Saturn 20 • Solar System 14

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space

observatory

spacecraft