American-crewed space program

The Mercury program was the first phase of America’s effort to put
a human on the Moon by the end of the 1960s. On May 5, 1961, the first
piloted Mercury flight, Freedom 7, was launched. It took astronaut Alan
Shepard on a 15-minute suborbital flight (only a partial—not complete—
orbit of Earth) that went 116 miles (187 kilometers) up and 303 miles
(488 kilometers) across the Atlantic Ocean at speeds up to 5,146 miles
(8,280 kilometers) per hour. The capsule than parachuted safely into the
Atlantic Ocean with Shepard inside.
Two months later, another U.S. suborbital flight was launched, this
one carrying Virgil “Gus” Grissom. Grissom’s flight was similar to Shepard’s,
except at splashdown his capsule took in water and sank. Grissom
was unharmed, but his capsule, the Liberty Bell 7, was not recovered.
On February 20, 1962, just over nine months after Gagarin’s flight,
astronaut John Glenn became the first American to orbit Earth. His spacecraft,
Friendship 7, completed three orbits in less than five hours.
Lunar program. The Apollo program was created for the purpose of
landing American astronauts on the Moon. Engineers designed a craft
consisting of three parts: a command module, in which the astronauts
would travel; a service module, which contained supplies and equipment;
and a lunar module, which would detach to land on the Moon.
The Apollo program was not without mishap. During a ground
test in 1967, a fire engulfed the cabin of the Apollo 1 spacecraft, killing
Gus Grissom, Ed White, and Roger Chaffee. This tragedy prompted
a two-year delay in the launch of the first Apollo spacecraft. During
this time, more than 1,500 modifications were made to the command
module.
In December 1968, Apollo 8 became the first manned spacecraft to
orbit both Earth and the Moon. On July 16, 1969, Apollo 11 was launched
with astronauts Neil Armstrong, Edwin “Buzz” Aldrin, and Michael
Collins on board. Four days later Armstrong and Aldrin landed on the
Moon. When Armstrong set foot on lunar soil, he stated, “That’s one small
step for man, one giant leap for mankind.” The Apollo 11 flight to the
Moon is considered by many to be the greatest technological achievement
of the modern world. Over the next three years, five more Apollo missions
landed twelve more Americans on the Moon.

Space probes to the outer planets

NASA sent Pioneer probes to explore the outer planets. Pioneer 10
reached Jupiter in 1973 and took the first close-up photos of the giant
planet. It then kept traveling, crossing the orbit of Pluto and leaving the
solar system in 1983. Pioneer 11 traveled to Saturn, where it collected
valuable information about the planet’s rings.
NASA next introduced the Voyager 1 and 2 probes, more sophisticated
versions of the Pioneers. Launched in 1977, they flew by Jupiter
two years later and took pictures of the planet’s swirling colors, volcanic
moons, and its previously undiscovered ring.
The Voyager space probes then headed for Saturn. In 1980 and 1981,
they sent back detailed photos of Saturn’s spectacular rings and its vast
collection of moons. Voyager 2 then traveled to Neptune, which it reached
in 1989, while Voyager 1 continued on a path to the edge of the solar system
and beyond.
After many delays, the U.S probe Galileo was launched from the
space shuttle Atlantis in 1989. It reached Jupiter in December 1995, and
dropped a barbecue-grill-sized mini-probe down to the planet’s surface.
That mini-probe spent 58 minutes taking extremely detailed pictures of
the gaseous planet before being incinerated near the surface. As of the
beginning of 2001, Galileo was still sending valuable scientific information
about Jupiter and its moons back to Earth.
In February 1996, NASA launched NEAR (Near Earth Asteroid Rendezvous)
Shoemaker, an unmanned spacecraft that was to become the first
to orbit an asteroid. In April 2000, it began a circular orbit around the asteroid
Eros. During its one-year mission around Eros, the spacecraft took
measurements to determine the mass, density, chemical composition, and
other geological characteristics of the asteroid. It also beamed some
160,000 images of Eros back to Earth. In February 2001, NEAR Shoemaker
used the last of its fuel in a successful attempt to land on the surface
of the asteroid. Once on the surface, it continued to collect invaluable
data about the oddly shaped Eros before it was finally shut down by NASA.

ISS systems and size

The ambitious ISS has been likened in difficulty to building a pyramid
in the zero gravity or weightlessness of outer space. When completely
assembled, the ISS will have a mass of nearly 1 million pounds (454,000
kilograms) and will be about 360 feet (110 meters) across by 290 feet (88
meters) long, making it much wider than the length of a football field.
This large scale means that it can provide 46,000 cubic feet (1,300 cubic
meters) of pressurized living and working space for a crew of seven scientists
and engineers. This amount of usable space is greater than the volume
of the passenger cabin and cargo hold of a huge Boeing 747-400 aircraft.
This massive structure will get its power from nearly an acre of
solar panels spread out on four photovoltaic (pronounced foe-toe-vole-
TAY-ik) modules. These solar arrays rotate to always face the Sun and
can convert sunlight into electricity that can be stored in batteries. The
station will have fifty-two computers controlling its many systems.
The main components of the ISS are the Service Module, which is
Russia’s first contribution, and then six scientific laboratories (one American,
one European Space Agency, one Japanese, and three Russian labs).
The other major contributor is Canada, which is providing a 55-foot-long
(16.7-meter-long) robotic arm for assembly and other maintenance tasks.
The United States also has the responsibility for developing and ultimately
operating all the major elements and systems aboard the station. More
than forty space flights over five years will be required to deliver these
and many other space station components to the orbiting altitude of 250
miles (402 kilometers) above Earth.

Because the study of infrared radiation is limited from Earth’s surface (water and carbon dioxide in Earth’s atmosphere block most of it), astronomer

Astronomers are still searching for why starburst galaxies form. Currently,
the most widely accepted theory is a collision or a close encounter
with another galaxy that starts a chain reaction. The impact of such a collision
produces shock waves throughout the galaxy that push on vast
clouds of interstellar dust and gas that are present. These shock waves in
turn cause the clouds to collapse and produce short-lived, massive stars.
The stars that form from this collision quickly use up their nuclear fuel
and explode in a supernova (an extremely bright new star). This explosion
produces yet more shock waves and consequently more star formations.
The formation of a starburst galaxy ends when its giant clouds of
gas are used up or pushed too far away due to the explosions.
Starburst galaxies often emit three-quarters of their light in the form
of infrared light. During the formation of stars, the large clouds of gas
and dust that the stars form in heat up and the dust emits infrared light,
which is able to get through the clouds of gas. But because the light that
comes through is infrared, starburst galaxies are relatively unspectacular
when viewed through a regular telescope. However, an infrared telescope
(a telescope that allows the user to see the usually invisible infrared wavelengths)
shows starburst galaxies standing out from all other galaxies because
of their brightness from the continuing formation of stars.
Starburst galaxies most often appear irregularly shaped when compared
to regular galaxies. Most galaxies are spiral or elliptical in shape.
For instance, both the Milky Way galaxy (our galaxy that includes a few
hundred billion stars, the Sun, and our solar system) and the Andromeda
galaxy (the nearest galaxy similar in size to the Milky Way, located
2.2 million light-years away) are spiral-shaped. Astronomers believe that
the irregular shape of starburst galaxies is due to their collision or nearcollision
with other galaxies.

Infrared Astronomical Satellite and the Hubble Space Telescope

Because the study of infrared radiation is limited from Earth’s surface
(water and carbon dioxide in Earth’s atmosphere block most of it),
astronomers had a limited knowledge of starburst galaxies. This changed
when an infrared telescope was mounted onto a satellite observatory that
was sent into space in 1983. Three countries—the United States, England,
and the Netherlands—combined their efforts to develop and launch the
Infrared Astronomical Satellite (IRAS). The IRAS was equipped with an
infrared telescope that observed, among other things, that thousands of
starburst galaxies exist in space. It also showed that starburst galaxies
consist of nearly one-third of the energy in the universe, suggesting that
starburst galaxies are the main source of new stars.
Another high-tech space observatory was launched in 1990. The
Hubble Space Telescope (HST) was sent into space and acted as an
observatory for astronomers from dozens of countries. With its highresolution
camera sending back sharp pictures to Earth, the HST showed
that violent star formations—typically thought to occur only in distant
galaxies—also occurred in the closest starburst galaxy (about 1,000 lightyears
from Earth). The HST also confirmed the theory that stars are often
born in dense clusters (close groupings) within starburst galaxies.