Jakob Huber <chakob@hotmail.com>
Space
Exploration
Spezialgebiet in Englisch
Jakob Huber
Table of contents
Introduction ......................... page 2
1. The
Sputnik
Shock
page 2
2.The
Mercury
Project
page 3
2.1. What was Mercury about?
2.2. Mission History
2.3. The importance of Mercury
3.“Twins”
in
space:
Gemini
page 4
3.1. Just another step on the way to the Moon?
3.2. Important Missions
4.From
the
Earth
to
the
Moon
page 6
4.1. From the Earth to the Moon
4.2. The Missions that Made History
5.Other
Apollo
Missions
page 8
5.1. Skylab
5.2. Apollo-Soyuz
6.“Revolution”
in
space:
the
Space
Shuttle
page 9
2
6.1. The Design of the Space Shuttle
6.2. Shuttle Missions
7. The Mir Space Station.............. page 11
Bibliography ........................ page 12
3
Introduction
The stars have always fascinated us. This fascination was probably born when the
first human directed his eyes into the nightly sky. Of course, these ancient peoples
had no idea of the nature of the stars, so they made up fantastic myths about the stars.
They believed to see constellations in the stars, and even found rules how one could
predict the future by looking at them. For thousands of years these believes have
hardly changed. Finally, at the dawn of the modern age, thinkers, such as Copernicus
and Kepler, were able to reveal more secrets about the star, but still no sane being
thought that it would be possible to travel to the stars or at least to the Moon. The
first time that such a thought was discussed when Jules Verne wrote his visionary
book “From the Earth to the Moon.”
It was not before the end of World War II, however, when people became serious
about traveling to the Moon. It was the time of the Cold War and both superpowers
were struggling to prove that they possessed superior technology. At first the Soviet
Union seemed to be ahead but the United States were far from admitting defeat in the
space race.
In the following I want to give you a more detailed picture about mankind’s way
into space. Since it was difficult to access Russian sources I had to focus on the
American efforts.
1. The Sputnik Shock
In both Russia and the United States the space race was a military project in the
beginning. In the Soviet union it was headed by Sergei Pavlovich Korolev. In the 30s
he led an amateur rocketry organization. In the 40s and early 50s he was forced to
work in Stalin’s labor camps.
After Stalin’s death he was allowed to focus on his rocket project again. On May
20, 1954, his design bureau got an order from the government to develop the first
Russian intercontinental ballistic missile (ICBM). Some plans already existed for the
so-called R-7. It was supposed to be an offensive weapon against the United States
that could be launched from Russian territory. Six days later he handed over a paper
that was written by his friend M. Tikhonravov. It was titled “Report on an Artificial
Satellite of the Earth”. It stated that the R-7 missile could be used to launch satellites
into space. Yet, the R-7 remained a military project. The military officials intended it
to be a weapon and were reluctant to admit missile launches with it.
About a year afterwards the first Soviet Organization devoted to space flight was
born. In August 1955 Korolev presented a new paper to a Soviet governmental
commission. The R-7 should be used to lift a 1500kg object into space. Based on the
report he received permission to use the rocket as a satellite launcher. Many Soviet
military leaders were against the project because they feared that it might interfere
with the ballistic missile development. Korolev was able to convince the Soviet
leader Khrushchev of the contrary. The program could finally be started.
In the first days the program was processing slowly. It was formally approved on
January 30, 1966, months after the plans were turned in. Subcontractors were not
4
making required deliveries. Worst of all the R-7 did not have enough thrust to lift the
heavy satellite. Its weight had to be reduced form 1500kg to 100kg.
The program was nearing completion in August 1957 when the first Russian ICBM,
the R-7 was successfully tested. The rocket was now being modified for the world’s
first satellite launch. It had two stages and a length of 29 meters. On October 4, 1957
the rocket was ready for launch. Six minutes after lift-off Sputnik was released.
Sputnik was designed to determine the density of Earth’s upper atmosphere.
However, it only transmitted signals for a short time. A month later, a second Sputnik
was launched. It brought the first living being into space, the dog Laika. For about a
week medical data was collected. Afterwards the dog had to be put to sleep since a
safe reentry was not possible at that time. The last Sputnik that was shot into space
was the one that was intended to go up first. It was launched on May 15, 1958. For
two years it performed experiments on the Earth’s magnetic field and ionosphere.
The launch of Sputnik was a shock to the western world since there were no
previous announcements. The Russians seemed to be ahead of the Russians. In order
to close this gap the National Aeronautics and Space Organization (NASA) was
created on October 1, 1958.
2. The Mercury Project
2.1. What was Mercury about?
Project Mercury was launched one year after Sputnik was shot into space on
October 7, 1958 as NASA’s first project. It had three prime objectives.
-
to send manned spacecraft into orbit (circle Earth)
-
to find out weather humans can work properly in space, and
-
to recover both man and spacecraft safely.
The Mercury engineers were true pioneers. Nothing that they were doing has ever
been done before. The engineers had to build a space capsule that protects humans in
space from the vacuum, the freezing cold temperatures, the radiation of space that has
just been discovered, and the astronauts had to survive the heat of the reentry into the
atmosphere during which the spacecraft would be flying very fast.
The engineers found that the ideal shape for the spacecraft was bullet-like. They
put strong heat shields on the front side so that the astronaut could survive the reentry.
The Mercury capsules were driven into space by to different propulsion systems. At
first the astronauts were boosted into space by Redstone Rockets which were only
good for sub-orbital flights. Later the more powerful Atlas-D rockets were used. The
Atlas-D was a modified ballistic missile. Its skin was extra thin to safe weight, so that
it had to be pressurized from within.
Compared with today’s standards the Mercury capsules were very small. They had
about 12,000m
3
of Volume which is just the right size for one person to squeeze in.
The internal controls were powered with batteries. Inside there were 120 controls,
and 90 switches and levers. Despite that great number of instruments Mercury was
only able change its orientation in space.
2.2. Mission History
5
Out of a group of 110 military pilots, seven were chosen to become America’s first
Astronauts, the Mercury Seven. They all gave their spacecraft a name which ended
with a 7 to emphasize the teamwork among them. Before they could go on their
mission tests on animals, and even a breathing robot were conducted.
On May 5, 1961, a Redstone, that was given the name Freedom 7, was ready to take
off. It took Allan B. Shepard Jr. on a 15 minute space ride that was watched by 45
million Americans on TV. He had the experience of weightlessness for five minutes
while he was traveling in a height of 187km.
Nine months later it was John H. Glenn’s turn to make the first trip with an Atlas-
D, which he had named Friendship 7. Glenn remained in the orbit for almost five
hours, circling Earth three times. After experiencing a sunrise and a sunset in space
he returned safely to Earth as a national hero. The primary objective of the “Mercury
Project” was thus fulfilled.
Other Mercury missions followed, most noticeably Faith 7 the last one which
started in May 1963. It was supposed to be an endurance test. L. Gordon Cooper
spent 34 hours in space and rounded Earth 22 times. On board he slept, and made
some great pictures of the Earth. He was also the first person to launch a satellite in
space.
2.3. The Importance of Mercury
The Mercury Project answered many of the basic questions about space flight. It
has proven that is possible to build rockets that are strong enough to launch humans
into space, and that they could survive there. The engineers gained much experience
and learned about the difficulties of preparing a rocket. It also showed that a global
communications network was necessary to make the missions more secure.
The program was so successful that the last scheduled mission could be canceled.
President Kennedy announced in 1961 that the United States would reach the Moon
before the end of the decade. By 1963 most of the Mercury engineers had already
been working on NASA’s other projects: Gemini and Apollo.
3. “Twins” in space: Gemini
3.1. Just another step on the way to the Moon?
After the success of Mercury the Gemini Program was showing the Gemini
Program was introduced to the public on January 3, 1962. At this time Apollo had
already been called into life. To the public it was not as interesting as Mercury or
Apollo since it was not real pioneering anymore. It was a mere preparation for the
Apollo program. The Gemini Program had three main objectives.
The first was to accomplish space fights of two weeks in duration. The lunar
missions would later take the same time. So NASA had to demonstrate the man and
machine could work in space for so long.
The second goal was to dock with orbiting vehicles and to maneuver the docked
combination using the propulsion system. Later these techniques would be used when
the lunar lander separates from the command module in the lunar orbit.
6
The third was to perfect the methods of reentry into the atmosphere and land on a
pre-selected point on Earth. The goal of making a landlanding was canceled in 1964,
however.
The Gemini capsule was an improvement of Mercury. That’s why it was originally
called “Mercury Mark II”. It had to be maneuvered by two pilots. The module had
twice the weight of the Mercury capsules, but size of the cabin was increased by only
50 per cent. As a result the Gemini capsules appeared to be more cramped. In case of
emergency the pilots could leave the capsule with an escape rocket instead of ejection
seats. The batteries that provided Mercury with electrical power were replaced with
fuel cells.
The capsule sat on a Titan 2 launch vehicle. The docking maneuvers were
practiced with unmanned Agena upper stages
1
that were always started shortly before
the Titan 2 rockets. In order to fly the complicated docking maneuvers the
maneuvering capabilities of Mercury have been improved a lot. Gemini was able to
fly forward, backward, and sideways on its way around Earth. It was even possible to
change orbits. These maneuvers required great precision, so besides the two
astronauts the first board computers were required to make complex calculations.
The constructors of Gemini had to avoid long delays between the flights. Many
parts of the spaceship were reusable. Thus the coast of the project have also been
lowered. In only 20 months ten Gemini missions were launched. As there was little
time between the flights space flight became routine. The ground operations became
smoother and the risk for the astronauts decreased after every mission.
3.2. Important Missions
The first manned Gemini mission (Gemini 3) took off on March 23, 1965. It was a
successful test of the design and lasted just four hours. The first full-time Gemini
mission was launched on June 3, 1965, and returned safely four days later. Its
highlight was the first space-walk ever. James McDivitt left the capsule for 22
minutes tied to a tether.
The goal of a two week space flight was accomplished by Gemini VII from
December 4-18, 1965. The mission solved many problems of long-duration space
flight. It included studies of nutrition in space and proved that even longer trips to
space do not pose a threat to the astronaut’s health. The Gemini VII pilots also
managed to rendezvous
2
with an Agena for the first time.
The most exciting Gemini mission was undoubtedly Gemini VIII that took off on
March 16, 1966. Its objective was to achieve the first docking maneuver ever. The
pilot Neil Armstrong approached the Agena carefully and managed to dock. The
successful action was almost followed by a catastrophe. While docked to the Agena
the Gemini capsule began rolling over. A thruster was stuck and could not be
deactivated. The crew undocked immediately and the capsule began rotating even
faster, at the rate of one revolution per second. In order to stop the motion the
astronauts had to use their reentry thrusters. They used up much of their fuel so that
1
The Agena was originally developed by the U.S. Airforce in 1956. Later it was modified to put satellites
into precise orbits and to propel space probes towards other planets.
2
At a rendezvous the astronauts move their space ship within a distance of fewer than one meter and maintain
this position for a few minutes or hours.
7
an emergency landing had to be made as soon as possible. 10 hours after launch
Gemini VIII was already back on Earth.
The last Gemini mission was launched on November 11, 1966. By then all the
goals of the Gemini project had been accomplished. Space-walks and complicated
maneuvers such as rendezvous and docking procedures had become routine. Fears
about the risks to health had been eliminated. The final objective of Gemini
(smoothing the reentry) has been completed when the board computer controlled the
reentry. Now it was time to tackle the next mission: the flight to the Moon.
4. From the Earth to the Moon
4.1. The technical aspects of Apollo
The Apollo Program was initiated in July 1960, a year earlier than Gemini. At first
its prime objective was to fly astronauts around the Moon. Another program including
a lunar landing was planned to follow. When President John F. Kennedy declared that
an American astronaut would be landing on the surface of the Moon before the end of
the decade Apollo shifted its focus. Besides taking men to the Moon the program had
two other objectives. The first was to establish the technology to meet other national
interests. The second one was to achieve preeminence for the United States in space.
Apollo was not just pioneering like Mercury. The constructors also wanted to
discover new technologies that could be used for later missions such as skylab.
The Apollo spacecraft consisted of three modules. The command module, the
service module and the lunar module. The command module functioned as living
quarters for the three-man crew. The cylindrical-shaped service module contained the
supplies for the astronauts and the Service Propulsion System engine which was used
to maneuver in the lunar orbit.
The lunar module was the first true spacecraft. It was designed for space flights
only. Thus, it did not have any aerodynamic qualities. It could separate from the
command/service module in the moon orbit taking two astronauts down to the surface.
In order to boost the Apollo vehicles the strongest rockets in history were built.
The Saturn V was 110 meters high and fueled it had a total weight of 2.7 million
kilograms (!). It was parted in three stages. Each stage was to be disjoined from the
rocket after it burnt out. Then the next one would start burning to take the space ship
closer to the Moon.
The lunar missions were highly complex and required faster ground operations than
Mercury and Gemini since there were now two objects to track in space. The
astronauts had to practice hard for their mission. Altogether they spent 84.000 hours,
this are nearly 10 man years, on geology field trips, simulations of lunar gravity, and,
of course, flying the lunar vehicle.
4.2. The Missions that Made History
The United States lost some of its astronauts for the first time as Apollo was
nearing completion. It happened on January 27, 1967, when a test for the first
manned Apollo mission was scheduled. The command module caught fire, trapping
8
three astronauts inside. The intense investigation and the modifications to Apollo
delayed the program for more than a year.
The next manned mission left off on October 11, 1968. It did not start with the
lunar module and remained in Earth orbit to conduct tests on Apollo’s other
components. The cabin for the astronauts was larger than Gemini’s but still the
eleven days of the mission took their toll on the astronauts. They complained about
the bad food, and everyone developed a cold.
Apollo 8 that left ground on December 8, 1968, was the first space ship that took
astronauts around the moon. Originally a test of the lunar module in Earth orbit was
intended but plans had to be changed when it became obvious that the Soviets were
catching up. The lunar module for Moon landings still was not included. Instead the
service propulsion system for navigation around the moon was tested.
Two missions with further tests followed. Then the time to make history has come for
the crew of Apollo 11. On July 20, 1969, four days after lift-off, Neil Armstrong put
his feet on the lunar surface speaking his famous words: "That's one small step for
man . . . one giant leap for mankind." He and Edwin Aldrin spent 21 hours on the
surface of the Moon. They left a flag of the United States of America and a plaque
with the following words engraved: “H
ERE
M
EN
F
ROM
P
LANET
E
ARTH
F
IRST
S
ET
F
OOT
U
PON
T
HE
M
OON
. J
ULY
1969 AD W
E
C
AME
I
N
P
EACE
F
OR
A
LL
M
ANKIND
.” Four days
later they returned to Earth as heroes.
With Apollo 11 the objectives of the program were basically met. The USA not
only won the race against the Russians they also proved that it was generally possible
to reach other worlds. Even if there is going to be a Mars mission it will never
overshadow the great achievement of making the first trip to another planet. It will
just be another step of mankind on its way to the stars.
Six other Moon missions were scheduled. One of them never reached its goal.
Tragedy almost struck on Apollo 13 when on oxygen tank in the service module
exploded within 321,860 kilometers of Earth. The only way to safe the lives of the
astronauts was to abort the moon landing and to return to Earth by using the gravity
forces of the Moon. The command module of the space ship was almost completely
inactive so the crew had to spend most of the time in the lunar module. After four
tense days in space Apollo 13 eventually returned back to Earth.
Apollo 17, the last mission, was launched on December 7, 1972. Like the crews of
the two preceding missions they had a moonrover that allowed them to get a better
overview of the lunar surface. The Apollo Program ended as Apollo 17 splashed into
the pacific on December 19, 1972.
5. Other Apollo missions
5.1. Skylab
Since the earliest days of the NASA space program concepts for a space station
were studied. They all failed, however, since there was no way of getting such a
station into orbit. As the powerful Saturn V rockets were invented in the mid-Sixties
for the Apollo program Skylab initially called the “Apollo Applications Program”,
was born. Leftover Apollo hardware was should be used to male longer stays of
astronauts in space possible.
9
At first there were two concepts for the Skylab mission. The concept of the “wet”
workshop was to launch one of the weaker Saturn IV-B rockets and then vent and
refurbish its upper stage in space. The second concept that was later realized was the
“dry” workshop.
According to the plan a Saturn IV-B upper stage was modified on ground. It was
divided into two levels. The “lower” one served as the astronaut’s living quarters. It
had three bedrooms, a dining table, a work area, as well as, a bathroom and a shower.
In the “upper” level there was a storage room and a large space for experiments.
The largest piece of equipment was the Apollo Telescope Mount (ATM). It was
attached to the end of the cylindrical workshop. Its purpose was to study the sun
without any atmospheric interference.
Furthermore, Skylab had an airlock module for space-walks. Space-walks were not
only required to do repairs but also to change the film in the ATM and to conduct
other experiments.
Skylab was launched into space by a Saturn V rocket on May 14, 1973. The crew
was scheduled to follow the next day but Skylab was damaged during the start. The
combined meteorite shield and sunshade was torn loose and took one of the two solar
arrays with it. Ten days later a fix was worked out and the astronauts were able to go
on the first of three skylab missions.
The three man crew failed had to complete the repairs as fast as possible since the
missing of the sunshade caused high temperatures in the station. These conditions
could have spoiled the food for the astronauts and the sensitive film material for the
ATM. They succeeded in setting up a parasol as a replacement for the sunshade but
failed to deploy the second solar panel which was also damaged. After two weeks the
repair was finally completed so that Skylab was provided with energy. After one
month the first Skylab mission was competed. Two more missions of two and three
months in duration followed. Until today, Skylab 4 is the longest mission ever carried
out by a U.S. astronaut. It lasted 84 days. Between the missions the space station was
deactivated. On July 11, 1979 the empty Skylab station burned up in the atmosphere.
The Skylab missions provided weather scientists with some valuable data. By
photographing targets on the sun and evaluating weather conditions on Earth some
valuable solar orientated material was obtained. The final crew also made
observations of he Comet Kohoutek that was coincidentally passing Earth. The
astronauts carried out lots of other experiments. For example they found out that
spiders were also able to spin webs in the state of weightlessness.
5.2. Apollo-Soyuz
Apollo-Soyuz was the last mission of the Apollo era. It was less a technical matter
than it was a political one. In 1972 U.S. President Nixon and the Soviet leader
Kosygin initiated the program. It was a symbol for the goodwill between the two
superpowers.
American and Soviet scientists had to grant each other inside into their respective
programs so that a common docking system could be designed. In preparation of the
flight Soviet cosmonauts were practicing at Johnson space center, and the American
crew did the same in Moscow. Flight controllers from both nations also conducted
joint simulations.
10
Apollo 18 and Soyuz 19 left Earth within seven-and-a-half hours on July 15, 1975.
Two days later Thomas P. Stafford and Alexei Leonov exchanged handshakes. The
two space ships remained linked for 44 hours. During that time they ate together,
exchanged gifts and flags and paid visits to each other’s ships. They also conducted
further docking maneuvers in which the Soyuz took over the role of the active ship.
The Soviets spent five days in space. The Americans concluded their trip after nine
days.
6. “Revolution” in space: the Space Shuttle
6.1. The Design of the Space Shuttle
The Space Transportation System, better known as the Space Shuttle, meant a
revolution to space flight in many ways. It was the first reusable space craft, and
allowed not only to take satellites into space but also to take them back to Earth.
Furthermore, many of today’s Shuttle flights are non-military operations
The Shuttle project was started in 1972. A spacecraft that could be used over and
over again proved to be a difficult task for the constructors. Insulating Tiles that are
able to stand the heat of the reentry and better engines which can survive many
missions had to be invented.
Space Shuttles are very different from the previous types of space crafts. They
look a little bit like airplanes and have got three main engines. These engines burn
the liquid hydrogen and oxygen that are stored in the large External Tank. Most of
the thrust for the lift-off, however, is derived from the two Solid Rocket Boosters
which are attached to the tank. Two minutes after lift-off they have burnt out and they
are dropped into the ocean for recovery. Eight minutes after he start the Shuttle has
reached the orbit and the Shuttles own engines are deactivated as well.
The Space Shuttle has a 18 meter long cargo bay where additional modules can be
placed. Respective to their mission the Space Shuttles can be equipped with mission
specific tools or modules. One of them is the Spacelab Module. It was built by the
European Space Agency and provides the astronauts with a fully equipped laboratory.
It allows scientists to conduct experiments ranging in subject matter from astronomy
to biomedical examinations. Another important tool is the Remote Manipulator
System, a 15 meter crane. It is used to move heavy payloads such as satellites in and
out of the Shuttle. The Manned Maneuvering Unit backpack changed the art of space
walking. With it the astronauts could move outside their spacecraft without a
connecting tether and therefore work faster in their spacesuits.
In 1995 a new capability was added to the repertoire of the Shuttle. In order to
prepare for the service on the International Space station, Shuttle crews began a series
of dockings with the Russian space station Mir. U.S. astronauts sometimes spent
months in space so that they get used to living and working in space.
Today the Space Shuttles make up a fleet of four spacecrafts. The first one,
Atlantis, entered service in 1981. It was followed by the Challenger (1983), the
Discovery (1984) and the Columbia (1985), and the Endeavour (1991).
6.2. Shuttle missions
11
Space Shuttles usually take off with a seven-man-crew. Such a large crew allows
to divide the astronauts into two categories. There are the pilots who are responsible
for flying and maintaining the orbiter and there mission specialists for experiments
and payloads. These specialists are not necessarily career-astronauts.
During the early missions the Space Shuttles often carried communications
satellites into the sky. Sometimes three satellites were place in orbit during one single
mission.
This policy changed when the greatest catastrophe in human space flight so far took
the lives of seven astronauts. On January 28, 1986, the Challenger exploded just 73
seconds after lift-off. Later it was determined that a seal in one of the two Solid
Rocket Boosters did not work properly due to the freezing cold temperatures that day.
The Shuttle program was suspended for over two years in order to make several
improvements to the other Shuttles.
The number of flights was greatly reduced as a result to the accident. Today the
Shuttles are only used when a payload requires them or when human presence is
absolutely necessary. The majority of the missions were of defensive or scientific
nature. Most recent payloads include the decade’s most important space science
projects such as the Hubble Space Telescope , the Galileo Jupiter spacecraft, and the
Gamma Ray Observatory. The most recent Shuttle mission was launched on
December 4, 1998. The Endeavour brought a module for the International Space
Station into orbit and the crew connected it to the Functional Energy Block that is
already in space. The next Shuttle launch is going to be on May 20. The Discovery
crew is also going to work on the International Space Station. This mission will be
the 95
th
Shuttle mission.
7. The Mir Space Station
After Skylab Mir was the second permanent space station. Its core was launched
on February 19, 1986. Over ten years later it was completed with the adding of the
Remote Sensor Module. During its 13 years in orbit it was a home for 62 cosmonauts
from 24 different countries.
Mir is floating 390 km above Earth. A Russian cargo and resupply vehicle is used
to send science equipment and data to and from the station. Each transport also
includes food and water supplies for Mir. When it is leaving the station it takes care
of the removal of waste materials.
The entire complex is composed of six modules. The most important of the is the
core module. It has a total length of 43 meters and contains the crew’s living quarters
and control area. Each cosmonaut has got a room for himself as well as a personal
hygiene area. From the control area the crew has got access to every major system on
board. The core has got multiple docking ports where additional modules are attached
to. They also allow space craft dockings.
Mir has got four additional modules. Besides contributing to the station’s energy
supply and adding storage space for food and water the modules have got a special
purpose. The astrophysics module Kvant-1 gathers information from far-away stars,
Kvant-2 provides laboratory areas for biological research. In addition it has an airlock
for space walks. The Kristall Technological Module is used for material development
in a space environment, and has got a docking port that can be used with the Space
12
Shuttle. The Remote Sensing Module contains a number of Spectrometers. Its
purpose is to make observations of the Earth atmosphere.
Bibliography
!
David Baker: Space Flight and Rocketry
Facts on File, Inc., 1996, ISBN 0816018537
!
Judy A. Rumerman: Human Space Flight: A Record of Achievment
Mikaya Pr., 1998, ISBN 1265403210
!
David S. F. Portree: NASA’s Origins and the dawn of space age
Enslow Publishers, Inc., 1995, ISBN 1876254040