North Hawaii News Articles from CFHT
Milestone achieved for the International Space Station
Last November saw a milestone for the International Space Station
(ISS). Two Russians and one American were flown to the ISS for a 4 month
long stay, 350 km above Earth, circling it every hour and a half. Even
though there were a few other space stations before ISS (Russian Salyut
modules and space station Mir, and the American SkyLab), ISS will
benefit from new technologies and more resources than its predecessors,
thus providing space for more scientific experiments, and larger
crews.
Construction of the ISS started in November 1998, when the first module,
Zarya, was launched. The Unity module was joined to Zarya a few weeks
later, and Zvezda was added in July 2000. As those names may tell you,
the ISS is an international effort to build an space station. Apart from
the USA and Russia, Canada, Brazil, Japan and 11 European countries are
participating in this huge 20-year 100 billion dollar (US)
project.
Currently, with its 3 modules, the ISS is 37 meters (121 feet) long and
weighs 60 tons. When completed (in 2006 if everything goes well) with
about 30 modules, it will be 109 meters (360 feet) wide, 90 meters (290
feet) long, 45 meters (143 feet) tall and weigh 450 metric tons (1
million pounds). Up to 7 astronauts will have a living and working space
roughly equivalent to the passenger cabin volume of two 747 jumbo
jets.
What will those astronauts do up there? The International Space Station
is expected to be used during its 15 year lifespan for research and also
commercial production. In this gravity-reduced environment, the
scientist-astronauts will conduct experiments in biology, ecology,
medicine, material sciences, and Earth monitoring, to name a few.
For example, protein crystals may be grown for long periods of time in
the space station. Without the effects of Earth's strong gravity, the
structure of these crystals will be more regular, resulting in purer
substances that will be studied for possible use in medical
treatments.
Gravity, or the lack of it, also affects the flames of combustible
materials, and allows the study of combustion phenomena that are not
observed on Earth. The lack of gravity also produces metals in which the
different elements are mixed more thoroughly and homogeneously, allowing
the manufacture of better metal alloys (stronger and lighter), and more
perfect materials that can then be used in computer chips, for
example.
Circling above the Earth, the ISS has a unique view on our planet's
surface. Major changes in the environment, such as massive forest
devastation, crop destruction by insects, or pollution, can be
witnessed, studied and monitored from above. Weather forecasting will
benefit from observations of our planet's atmosphere.
The humans living on board the space station will also be affected by
the reduced gravity, and numerous tests will be performed to better
understand the effects of weightlessness on the human physiology. We
already know that astronauts begin losing the calcium in their bones
after a few days in space, a phenomenon from which elderly people also
suffer! Studies conducted in space may help better understand why this
happens, and what can be done about it. In addition to helping people on
Earth, this knowledge will surely be useful when we are ready for a Moon
base or Mars expedition.
Experiments will also be conducted outside of the space station, where
vacuum, extreme temperatures variations, and impacts from
micrometeorites can be recorded. Since numerous communication
satellites, as well as military and scientific ones, are also affected
by these hazards, it is important to measure the effects and test new
materials in order to built better and more robust satellites.
The ISS orbits at an average altitude of 350 kilometers (220 miles)
above the Earth, at an inclination of 52 degrees to the equator. This
means that the station flies over most of the populated areas of our
planet, including Hawaii!
In fact, the ISS is very bright in the sky and can sometimes be seen,
just after sunset or before sunrise, for up to 10 minutes, passing
through a few constellations. A few resources on the Web can tell you
the next time ISS will be visible overhead.
In particular, the Heavens-Above site
(www.heavens-above.com) gives
10-day predictions on the visibility of the ISS (and other artificial
satellites too!) for over 2 millions cities in the world, including many
small towns on the Big Island (Waimea, Hawi, Honokaa and Kawaihae, for
example). Included in the predictions are a star chart, brightness of
the ISS, where to look and when to look.
Another Web site,
www.bester.com/satpasses.html,
will give more detailed information about the passes, although only for
Honolulu.
For more information, visit the ISS Web site:
http://www.shuttlepresskit.com/ISS_OVR/ or
http://spaceflight.nasa.gov/station/
Nadine Manset
Resident Astronomer
Canada-France-Hawaii Telescope Corporation
Dec. 7, 2000