(See description below)
Beefing Up the International Space Station
Astronaut Michael E. Lopez-Alegria, STS-113 mission specialist, works on the newly installed Port One (P1) truss on the International Space Station (ISS) during a session of extravehicular activity (EVA). The end effector of the Canadarm2 / Space Station Remote Manipulator System (SSRMS) is visible to the right.
The International Space Station is the largest and most
complex international scientific project in history. And when it
is complete just after the turn of the century, the the station
will represent a move of unprecedented scale off the home planet.
Led by the United States, the International Space Station draws
upon the scientific and technological resources of 16 nations:
Canada, Japan, Russia, 11 nations of the European Space Agency
and Brazil.
More than four times as large as the Russian Mir space station,
the completed International Space Station will have a mass of
about 1,040,000 pounds. It will measure 356 feet across and 290
feet long, with almost an acre of solar panels to provide
electrical power to six state-of-the-art laboratories.
The station will be in an orbit with an altitude of 250 statute
miles with an inclination of 51.6 degrees. This orbit allows the
station to be reached by the launch vehicles of all the
international partners to provide a robust capability for the
delivery of crews and supplies. The orbit also provides excellent
Earth observations with coverage of 85 percent of the globe and
over flight of 95 percent of the population. By the end of this
year, about 500,000 pounds of station components will be have
been built at factories around the world.
U.S. Role and Contributions
The United States has the responsibility for developing and
ultimately operating major elements and systems aboard the
station. The U.S. elements include three connecting modules, or
nodes; a laboratory module; truss segments; four solar arrays; a
habitation module; three mating adapters; a cupola; an
unpressurized logistics carrier and a centrifuge module. The
various systems being developed by the U.S. include thermal
control; life support; guidance, navigation and control; data
handling; power systems; communications and tracking; ground
operations facilities and launch-site processing facilities.
International Contributions
The international partners, Canada, Japan, the European Space
Agency, and Russia, will contribute the following key elements to
the International Space Station:
· Canada is providing a 55-foot-long robotic arm to be used for
assembly and maintenance tasks on the Space Station.
· The European Space Agency is building a pressurized laboratory
to be launched on the Space Shuttle and logistics transport
vehicles to be launched on the Ariane 5 launch vehicle.
· Japan is building a laboratory with an attached exposed
exterior platform for experiments as well as logistics transport
vehicles.
· Russia is providing two research modules; an early living
quarters called the Service Module with its own life support and
habitation systems; a science power platform of solar arrays that
can supply about 20 kilowatts of electrical power; logistics
transport vehicles; and Soyuz spacecraft for crew return and
transfer.
In addition, Brazil and Italy are contributing some equipment to
the station through agreements with the United States.
ISS Phase One: The Shuttle-Mir Program
The first phase of the International Space Station, the
Shuttle-Mir Program, began in 1995 and involved more than two
years of continuous stays by astronauts aboard the Russian Mir
Space Station and nine Shuttle-Mir docking missions. Knowledge
was gained in technology, international space operations and
scientific research.
Seven U.S. astronauts spent a cumulative total of 32 months
aboard Mir with 28 months of continuous occupancy since March
1996. By contrast, it took the U.S. Space Shuttle fleet more than
a dozen years and 60 flights to achieve an accumulated one year
in orbit. Many of the research programs planned for the
International Space Station benefit from longer stay times in
space. The U.S. science program aboard the Mir was a pathfinder
for more ambitious experiments planned for the new station.
For less than two percent of the total cost of the International
Space Station program, NASA gained knowledge and experience
through Shuttle-Mir that could not be achieved any other way.
That included valuable experience in international crew training
activities; the operation of an international space program; and
the challenges of long duration spaceflight for astronauts and
ground controllers. Dealing with the real-time challenges
experienced during Shuttle-Mir missions also has resulted in an
unprecedented cooperation and trust between the U.S. and Russian
space programs, and that cooperation and trust has enhanced the
development of the International Space Station.
Research on the International Space Station
The International Space Station will establish an unprecedented
state-of-the-art laboratory complex in orbit, more than four
times the size and with almost 60 times the electrical power for
experiments — critical for research capability — of
Russia's Mir. Research in the station's six laboratories will
lead to discoveries in medicine, materials and fundamental
science that will benefit people all over the world. Through its
research and technology, the station also will serve as an
indispensable step in preparation for future human space
exploration.
Examples of the types of U.S. research that will be performed
aboard the station include:
· Protein crystal studies: More pure protein crystals may be
grown in space than on Earth. Analysis of these crystals helps
scientists better understand the nature of proteins, enzymes and
viruses, perhaps leading to the development of new drugs and a
better understanding of the fundamental building blocks of life.
Similar experiments have been conducted on the Space Shuttle,
although they are limited by the short duration of Shuttle
flights. This type of research could lead to the study of
possible treatments for cancer, diabetes, emphysema and immune
system disorders, among other research.
· Tissue culture: Living cells can be grown in a laboratory
environment in space where they are not distorted by gravity.
NASA already has developed a Bioreactor device that is used on
Earth to simulate, for such cultures, the effect of reduced
gravity. Still, these devices are limited by gravity. Growing
cultures for long periods aboard the station will further advance
this research. Such cultures can be used to test new treatments
for cancer without risking harm to patients, among other uses.
· Life in low gravity: The effects of long-term exposure to
reduced gravity on humans – weakening muscles; changes in
how the heart, arteries and veins work; and the loss of bone
density, among others – will be studied aboard the station.
Studies of these effects may lead to a better understanding of
the body’s systems and similar ailments on Earth. A thorough
understanding of such effects and possible methods of
counteracting them is needed to prepare for future long-term
human exploration of the solar system. In addition, studies of
the gravitational effects on plants, animals and the function of
living cells will be conducted aboard the station. A centrifuge,
located in the Centrifuge Accommodation Module, will use
centrifugal force to generate simulated gravity ranging from
almost zero to twice that of Earth. This facility will imitate
Earth’s gravity for comparison purposes; eliminate variables
in experiments; and simulate the gravity on the Moon or Mars for
experiments that can provide information useful for future space
travels.
· Flames, fluids and metal in space: Fluids, flames, molten
metal and other materials will be the subject of basic research
on the station. Even flames burn differently without gravity.
Reduced gravity reduces convection currents, the currents that
cause warm air or fluid to rise and cool air or fluid to sink on
Earth. This absence of convection alters the flame shape in orbit
and allows studies of the combustion process that are impossible
on Earth, a research field called Combustion Science. The absence
of convection allows molten metals or other materials to be mixed
more thoroughly in orbit than on Earth. Scientists plan to study
this field, called Materials Science, to create better metal
alloys and more perfect materials for applications such as
computer chips. The study of all of these areas may lead to
developments that can enhance many industries on Earth.
· The nature of space: Some experiments aboard the station will
take place on the exterior of the station modules. Such exterior
experiments can study the space environment and how long-term
exposure to space, the vacuum and the debris, affects materials.
This research can provide future spacecraft designers and
scientists a better understanding of the nature of space and
enhance spacecraft design. Some experiments will study the basic
forces of nature, a field called Fundamental Physics, where
experiments take advantage of weightlessness to study forces that
are weak and difficult to study when subject to gravity on Earth.
Experiments in this field may help explain how the universe
developed. Investigations that use lasers to cool atoms to near
absolute zero may help us understand gravity itself. In addition
to investigating basic questions about nature, this research
could lead to down-to-Earth developments that may include clocks
a thousand times more accurate than today’s atomic clocks;
better weather forecasting; and stronger materials.
· Watching the Earth: Observations of the Earth from orbit help
the study of large-scale, long-term changes in the environment.
Studies in this field can increase understanding of the forests,
oceans and mountains. The effects of volcanoes, ancient meteorite
impacts, hurricanes and typhoons can be studied. In addition,
changes to the Earth that are caused by the human race can be
observed. The effects of air pollution, such as smog over cities;
of deforestation, the cutting and burning of forests; and of
water pollution, such as oil spills, are visible from space and
can be captured in images that provide a global perspective
unavailable from the ground.
· Commercialization: As part of the Commercialization of space
research on the station, industries will participate in research
by conducting experiments and studies aimed at developing new
products and services. The results may benefit those on Earth not
only by providing innovative new products as a result, but also
by creating new jobs to make the products.
Assembly in Orbit
By the end of this year, most of the components required for the
first seven Space Shuttle missions to assemble the International
Space Station will have arrived at the Kennedy Space Center. The
first and primary fully Russian contribution to the station, the
Service Module, is scheduled to be shipped from Moscow to the
Kazakstan launch site in February 1999.
Orbital assembly of the International Space Station will begin a
new era of hands-on work in space, involving more spacewalks than
ever before and a new generation of space robotics. About 850
clock hours of spacewalks, both U.S. and Russian, will be
required over five years to maintain and assemble the station.
The Space Shuttle and two types of Russian launch vehicles will
launch 45 assembly missions. Of these, 36 will be Space Shuttle
flights. In addition, resupply missions and changeouts of Soyuz
crew return spacecraft will be launched regularly.
The first crew to live aboard the International Space Station,
commanded by U.S. astronaut Bill Shepherd and including Russian
cosomonauts Yuri Gidzenko as Soyuz Commander and Sergei Krikalev
as Flight Engineer, will be launched in early 2000 on a Russian
Soyuz spacecraft. They, along with the crews of the first five
assembly missions, are now in training. The timetable and
sequence of flights for assembly, beyond the first two, will be
further refined at a meeting of all the international partners in
December 1998. Assembly is planned to be complete by 2004.