Climate Monitoring | Interest Mounting in ISS as an Earth Observation Platform
SAN FRANCISCO — A camera built at NASA’s Marshall Space Flight Center to capture high-resolution images of fires, floods and other environmental disasters is scheduled to travel to the international space station (ISS) on the July 21 flight of Japan’s cargo-carrying H-2 Transfer Vehicle-3.
Once the camera is installed in the science window of the space station’s Destiny module and powered on, Marshall researchers plan to begin using it to learn how this type of instrument could assist in environmental monitoring and emergency response activities.
The camera, known as the ISS Server Environmental Research and Visualization System (ISERV) Pathfinder, was designed and built as part of the Servir program, a joint effort of NASA and the U.S. Agency for International Development to provide space- and ground-based data products and forecasts to communities in Central America, the Caribbean, Africa and the Himalayan region. The ISERV program does not have funding to use the ISERV Pathfinder to aid in disaster response activities; instead the program is designed to provide researchers with experience in operating this type of instrument and assist engineers in designing more capable instruments that may be mounted outside the space station, said Burgess Howell, Servir principal investigator at the Marshall Space Flight Center in Huntsville, Ala. ISERV program officials will practice tasking the ISERV Pathfinder to focus on disaster sites when the space station passes over the region, gathering imagery and obtaining the data through NASA’s Tracking and Data Relay Satellite System.
Astronauts are scheduled to install the ISERV Pathfinder in the Destiny module’s Window Observational Research Facility in October and turn it on in November. Then, ISERV program officials plan to spend “a few months” calibrating the instrument and conducting exercises to verify the performance of the camera, software and ground station before sharing imagery with Servir research teams, Howell said.
The ISERV Pathfinder program presented significant challenges to the Servir team. Because the space station requires periodic boosts to maintain its orbit, it is difficult to predict exactly when it will pass over a specific site on the globe unlike Earth observing satellites that follow a well-defined route, Howell said. In addition, ISERV program officials had to design, build and test the Pathfinder camera and supporting systems very quickly because they received authorization to proceed with the program in late February 2011 and shipped it to Japan in January, said Susan Spencer, Marshall’s ISERV project manager.
Since the goal of the ISERV Pathfinder program was to develop a low-cost, high-performance optical system, NASA engineers began with a commercial 23.5-centimeter telescope and added custom-made optical components, software, pointing and mounting systems. In addition, program officials developed a dedicated power supply system for the camera because no source was available on the space station, Spencer said.
Since the camera remains inside the space station, it did not need to be built to withstand the extreme temperatures and radiation of space. The location of the orbiting outpost also helped lower the cost of the optical systems used in the ISERV Pathfinder. The space station’s orbit of approximately 400 kilometers above Earth compared with 800 kilometers for most remote sensing satellites is an excellent spot for obtaining high-resolution imagery, Howell said. The ISERV Pathfinder is designed to provide imagery with 2.8-meter resolution.
Other Earth observation teams are recognizing the value of using the space station’s unique vantage point, said Julie Robinson, international space station program scientist at NASA’s Johnson Space Center in Houston. Since the United States government committed its support to the international space station until 2020, interest in sending remote sensing tools to the platform has grown. “Once we knew the space station would be around at least until 2020, it made a lot of sense to use it to develop and test new Earth observation instruments,” she added.
Researchers often use the space station as a test platform because it is much less expensive to send an instrument there than to launch and fly it independently, Robinson said. In addition, the space station’s optical window allows researchers to test sensors before launching them on satellites or mounting them on the station’s external platforms, she said.
During the next four years, several new instruments are scheduled to be sent to the space station, including a laser imaging detection and ranging, or lidar, system designed to study clouds, and a sensor that will peer at the sun through the atmosphere to detect environmental changes, Robinson said.
The space station has room to mount approximately two dozen Earth observation instruments. All those slots are scheduled to be filled by 2016, prompting space station officials to investigate where additional remote sensing instruments could be mounted. “Everyone is scrambling to see where they want to place their instruments and make their reservation,” Robinson said. “This capacity is now being recognized as being so valuable.”