August
7, 2009: The International Space Station has a new
"engawa"—and it's open for business.
Engawa
is Japanese for "porch," and while that might seem
like a strange thing for a space station to have, researchers
have been looking forward to the addition for a long time.
Space shuttle Endeavour delivered the Japanese-built platform
to the ISS on July 22nd and astronauts attached it to Japan's
Kibo1 science lab a day later. Now, when a science
experiment requires a dose of hard vacuum or radiation, it
can be set "out on the porch" for exposure.
And
that's just for starters.
Above:
The Japanese Exposed Facility seen from inside the International
Space Station's Kibo science lab. [more]
"On
the new 'Japanese Exposed Facility' [JEF for short], researchers
can stage experiments to look up at the cosmos, down at Earth,
or around at the environment the ISS voyages through,"
says Julie Robinson, ISS Program Scientist at NASA's Johnson
Space Center. "Besides resembling a porch, this structure
has unique features that differentiate it from the experiment
exposure points2 located elsewhere on the station."
For
instance, the JEF offers temperature control. Like the space
station's other external experiment locations, it has a warming
plate for thermal control, but unlike the others the JEF includes
a cooling feature.3 Another advantage is that JEF
experiments can be serviced by Kibo’s robotic arm4.
"The
beauty of this is that payloads can be designed to be 'plug
and play,'" says Robinson, "so the robotic arm can
install them -- no space walk required."
On
July 24th, Kibo's arm deftly delivered the first two JEF experiments
from the Shuttle payload bay to the porch and positioned them5.
These Japanese experiments are the SEDA-AP6, short
for Space Environment Data Acquisition equipment-Attached
Payload, and MAXI7, or the Monitor of All-sky X-ray
Image.
"SEDA-AP's
sensors will measure the space environment of low Earth orbit
-- neutrons, plasma, heavy ions, high-energy light particles,
atomic oxygen, and cosmic dust," explains Robinson.
With
this experiment, researchers can test the mettle of materials
and equipment exposed to the UV light, deep space radiation,
and extreme temperatures of space. SEDA-AP will monitor material
degradation to help researchers choose the hardiest materials
for building future space instruments, equipment, and vehicles.
Right:
A computer-generated image of Kibo's robotic arm placing the
Space Environment Data Acquisition equipment-Attached Payload
"out on the porch." [animations]
MAXI
is an all-sky X-ray scanner with super-sensitive X-ray slit
cameras to search continuously for exploding stars, black
holes, and other hot cosmic X-ray sources. Earth's atmosphere
absorbs X-rays (lucky for us), so astronomers have to send
their sensors to orbit.
"MAXI
will look at more than 1000 different X-ray sources and cover
the entire sky," says Tai Nakamura8 of JAXA
(Japan Aerospace Exploration Agency). Data from MAXI will
be broadcast on the Internet. Upon detecting an X-ray source,
MAXI's ground communication system will speed alerts to observers
across the globe within 30 seconds.
The
U.S. has two experiments destined for the JEF this fall: HREP-RAIDS,
or the Remote Atmospheric and Ionospheric Detection System,
and HREP-HICO, or the Hyperspectral Imager for the Coastal
Ocean.9
"RAIDS
will tell us about upper layers of Earth's atmosphere called
the thermosphere and ionosphere," says Robinson. "These
layers are tremendously imortant because that is where many
spacecraft and satellites orbit. According to the Naval Research
Laboratory, RAIDS is the most comprehensive survey of the
thermosphere and ionosphere in 20 years."
HICO,
also built by Naval Research Laboratory, is a hyperspectral
imager for mapping coastal areas.10 That simply
means it collects detailed information on the light reflected
from these locations. Traditional multispectral sensors, like
Landsat, lump the light measured into only a few bands; hyperspectral
sensors have hundreds of bands.
Right:
The Hyperspectral Imager for the Coastal Ocean (HICO) will
be installed on the space porch this fall. [more]
"Hyperspectral
sensors are like Landsat on steroids," says Robinson.
"But HICO is a test unit that lacks Landsat's spatial
resolution. Similar imagers have flown on aircraft, and another
hyperspectral imager is on NASA's Earth Observing-1 satellite
as a technology demonstration."
"The
JEF will help us figure out whether HICO would be feasible
for a satellite platform. The 'porch' is perfect for proving
imaging technologies in space before investing in sophisticated
optics for instruments and putting them on satellites. If
HICO passes with flying colors and an operational imager is
developed, that new imager could provide unprecedented maps
of coastal features."
The
JEF can host nine different experiments at once and has places
for communications equipment, storage, and for berthing Japan's
HTV-exposed pallet.11
Many
interesting new investigations are planned for the JEF. Stay
tuned to Science@NASA for updates from the porch.
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Author: Dauna Coulter
| Editor:
Dr. Tony Phillips | Credit: Science@NASA
end
notes |
(1)
Kibo home page.
(2)
For example, the European Space Agency's Columbus laboratory
has four mounting points for external payloads, and
NASA will position four Express Logistics Carriers on
the ISS truss on future assembly flights.
(3)
Without thermal controls, the temperature of the orbiting
space station's sun-facing side would soar to 250 degrees
F (121 C), while thermometers on the dark side would
plunge to minus 250 degrees F (-157 C).
(4)
According to JAXA, Kibo’s robotic arm (Japanese Experiment
Module Remote Manipulator System, or JEMRMS) is used
for exchanging or handling payloads and Orbital Replacement
Units on the JEF. The JEMRMS consists of the Main Arm
and the Small Fine Arm, which both have six articulating
joints. The Main Arm is used for handling JEF payloads.
The Small Fine Arm handles smaller items.
(5)
The Inter-orbit Communication System, or ICS, was also
placed on the JEF. The ICS offers a direct voice/image
channel to the Tsukuba Space Center Mission Control,
in Japan, via the nation's own satellite system.
(6)
SEDA-AP
home page.
(7)
MAXI
home page.
(8)
Tai is the Deputy Director of the Space Environment
Utilization Center for JAXA.
(9)
If you are an acronym hound, the definition for HREP
is HICO-RAIDS
Experiment Payload.
(10)
Such an instrument takes images of the land and/or ocean
in several different frequencies of light, including
some in the infrared part of the spectrum that the human
eye can’t see. This allows scientists to analyze the
spectral properties of the light reflecting off the
land and ocean, which provides much more information
about their characteristics than a normal photograph.
Data will include, for example, land use and land cover;
vegetation type, stress, and health; ocean depth; and
algae and sediment in coastal waters.
(11)
HTV is Japan's H-II
Transfer Vehicle.
NASA's
Future: US
Space Exploration Policy |
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