The International Space Station Agricultural Camera (ISSAC) will take frequent images, in visible and infrared light, principally of vegetated areas (growing crops, grasslands, forests) in the northern Great Plains region of the United States. The sensor also is being used to study dynamic Earth processes around the world, such as melting glaciers, ecosystem responses to seasonal changes, and human impacts, and including rapid-response monitoring of natural disasters. ISSAC was built and is being operated by students and faculty at the University of North Dakota, in Grand Forks, ND.Principal Investigator(s)
University of North Dakota, Grand Forks, ND, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
National Laboratory (NL)Research Benefits
Information PendingISS Expedition Duration:
March 2011 - March 2013Expeditions Assigned
27/28,29/30,31/32,33/34Previous ISS Missions
AgCam, the precursor to ISSAC was performed on ISS Expedition 19/20.
ISSAC is a multi-spectral camera destined for use on the ISS as a sub-rack payload of the Window Observational Research Facility (WORF). Primary ISSAC system components include an ISSAC Sensor Assembly (ISA), a Base Mounting Assembly, a Slide/Pointing Assembly, a Power/Data Controller, associated cabling and support items, and a NASA-supplied T61p Laptop, including power supply, and interconnecting power and data cables. The Base Mounting Assembly provides a solid mounting to the internal WORF payload support shelf. The Slide/Pointing Assembly has a slide mechanism to facilitate crew setup and activation within the WORF, and incorporates an integral gearbox and controller to point the lens assembly up to 30 degrees cross-track. The Power/Data Controller individually powers on the gearbox/controller and the ISA. Within the ISSAC Sensor Assembly, a vibration isolation and absorption system helps prevent excessive jitter in the ISSAC images. A single 150 mm lens and optical beam splitter supply light to three digital framing cameras, each with its own filter; green, red (630-690 nm) and near infrared (780-890 nm).
Nominally all payload operations are commanded via ground uplink. Commands are stored in an on-board command queue and executed based on system time supplied by the ISS. Imagery collected is downlinked via the medium-rate payload LAN. The onboard command queue capability can allow autonomous 24-hour operations, enabling routine worldwide target accessibility.
ISSAC is a space-related research project that will result in the delivery of direct benefits from space to the general public. Increasing the relevance of any space-related research activities with respect to the daily lives of the general public will benefit all ISS applications, whether for space or earth applications. By using ISSAC data in support of precision agriculture activities, the public will receive benefits synergistically from three different space systems: (1) Earth-observing from the ISS; (2) in-field navigation from the Global Positioning System; and (3) data delivery via satellite communications. With respect to the educational aspect of the ISSAC project, using students to develop and operate ISSAC helps train the next generation of scientists and engineers that will work on future space-based applications.Earth Applications
For broad-band multi-spectral systems, the two most useful frequency bands for studying vegetation are the same red and the near-infrared bands that ISSAC will collect. Agricultural efficiency and competitiveness can be enhanced through the practical application of data products that are derived from reflectance measurements taken in these spectral regions. The combination of characteristics that ISSAC can provide ? high-temporal data acquisition in these two bands at medium-high resolution, and delivered with minimal latency ? will offer a unique data source that will allow aspects of agricultural efficiency that are of particular importance to the northern Great Plains to be investigated and improved. More generally, these same capabilities of ISSAC can be applied to scientific study of any areas undergoing rapid ecosystem change, worldwide. Potential targets range from natural systems (glacier melt, plant phenological transitions (spring green-up, fall senescence) to human impact (deforestation, urbanization); itself a major change agent. The rapid responsiveness of ISSAC imagery may also aid in disaster monitoring applications worldwide.
To be able to image the Earth, ISSAC requires the ISS to be in Local-Vertical-Local-Horizontal (LVLH) attitude control mode, and preferably with the ISS X-axis in the direction of the Velocity Vector (+XVV), though imaging is still possible in other velocity orientations (i.e., -XVV, etc.). In addition, the US Laboratory Window external shutter must also be open (within shutter Flight Rule constraints).
Once in operation, nominal imaging plans call for acquiring 2-4 images per orbit, 2-4 orbits per day. Contraints on maximum imaging performance are principally data dowlink and operational staffing; a practical upper limit is about 40-50 images per 24 hour period, on an episodic basis. Specific science investigations and application results may be achievable with only one or a few images of a target; others, such as agricultural uses, may require multiple images closely spaced in time, several times during a growing season, and repeated over 2-3 growing seasons.
Crew members have installed ISSAC components, including a T61p Laptop and related Government Furnished Equipment (GFE). No more crew support is needed for nominal operations, other than manual opening and closing of the Lab Window external shutter per standard flight rules, and a once-per-increment cleaning of an air inlet screen.
From within the ISSAC Science Operations Center (SOC) at the University of North Dakota, operators will receive ISSAC imagery requests from an extensive network of end-user participants and research scientists, and will convert these requests into specific sets of commands for uplink to ISSAC. Through coordination with NASA for WORF rack operations, image acquisition and other ISSAC operational commands will be uplinked to the ISSAC payload software, which will take images over specific areas of the Earth. Resultant imagery data will be downlinked and transferred to the University of North Dakota for processing and quick delivery to image requestors.
ISSAC was installed into the WORF on May 13, 2011.