Early Space Missions

Chapter 22

Section 2

Escape Velocity

• In order to break free of gravity, spacecraft must travel at speeds greater than 11 km/s.

Rockets

• Engines that have everything they need for burning fuel.

• 2 types:– Liquid-propellant rocket

• Can be shut down after they are started.

• Can be restarted.

– Solid-propellant rocket• Can’t be shut down after they are

started.

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Rockets

Use physics (opposing forces) to propel the rocket forward.

Satellites• Any object that revolves around another

object.• Satellites travel in curved paths called

orbits (due to gravity).• Sputnik I, launched by Russia in 1957,

was the first artificial satellite.• Modern satellites are used for

communication, entertainment, and data collection.

Space Probes

• Sent through the solar system to gather and transmit data.

Space Probes

• Voyager Interstellar Mission– Voyager I and Voyager II– Launched in 1977.– Voyager I flew past Jupiter and Saturn– Voyager II flew past Jupiter, Saturn, Uranus, and

Neptune.– Expected to transmit data for another 20 years.

Space Probes• Pioneer 10

– Launched in 1972– First probe to survive a trip through the

asteroid belt and arrive at an outer planet.– Carries a gold medallion of a man, a woman,

and Earth’s position in the galaxy.

Space Probes

• Galileo– Launched in 1989– Released a smaller probe in 1995.

• The smaller probe approached Jupiter for 5 months and then parachuted through the atmosphere of Jupiter transmitting information to the satellite above it.

– Found that Europa may have an ocean and conditions for the possible existence of life.

– Found that Io has active volcanoes that erupt sulfur and oxygen.

Race to the Moon

• 1961 – Soviet cosmonaut, Yuri A. Gagarin, became the first human in space.

• Soon after, President Kennedy set a goal of putting a man on the moon by the end of the 60’s.

Race to the Moon

• Project Mercury– On May 5th, 1961 Alan B. Shepard became

the first U.S. citizen in space.– In 1962 John Glenn became the first U.S.

citizen to orbit the Earth.

Race to the Moon• Project Gemini

– Teams of 2 astronauts orbited the Earth and met up with another spacecraft in orbit.

– Gemini spacecraft were launched by a rocket liquid-fuel rocket known as Titan II.

– Used to examine the effects of space travel on the human body.

Race to the Moon• Robotic moon probes

– Ranger• Proved that spacecraft could be sent to the moon.

– Surveyor• Landed gently on the moon in 1966.

– Lunar Orbiter• Took pictures of the surface of the moon in order

to determine the best landing spot.

Race to the Moon

• Project Apollo– Apollo 11

• Landed on the moon on July 20th, 1969.• Neil Armstrong was the first human to set foot on the

moon.– Made the statement, “That’s one small step for man,

one giant leap for mankind.”

• Edwin Aldrin joined Armstrong and they explored the moon for 2 hours.

• Michael Collins remained in the Command Unit.

– A total of six lunar landings brought back more than 2,000 samples of rocks and lunar soil before the program ended in 1972.