Space Porch Open for Business
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."
"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.
(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.
(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.
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