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Space Test Program - Houston 3 - Digital Imaging Star Camera (STP-H3-DISC)


Overview | Description | Applications | Operations | Results | Publications | Imagery

Experiment Overview

This content was provided by Andrew Nicholas, and is maintained in a database by the ISS Program Science Office.

Brief Summary

Space Test Program - Houston 3 - Digital Imaging Star Camera (STP-H3-DISC) captures images of star fields for analysis by ground algorithms to determine the attitude of the International Space Station (ISS). The goal of this investigation is the creation of more robust and capable satellites to be controlled by ground systems for Earth-bound communications.

Principal Investigator(s)

  • Andrew Nicholas, Naval Research Laboratory, Washington, DC, United States
  • Co-Investigator(s)/Collaborator(s)

  • Ted Finne, Naval Research Laboratory, Washington, DC, United States
  • Ivan Galysh, Naval Research Laboratory, Washington, DC, United States
  • Mitch Whiteley, Space Dynamics Laboratory, North Logan, UT, United States
  • Chad Fish, Space Dynamics Lab, North Logan, UT, United States
  • Developer(s)

    United States Department of Defense Space Test Program, Johnson Space Center, Houston, TX, United States
    Utah State University, Space Dynamics Laboratory, North Logan, UT, United States
    Naval Research Laboratory, Washington, DC, United States

    Sponsoring Space Agency

    National Aeronautics and Space Administration (NASA)

    Sponsoring Organization

    National Laboratory - Department of Defense (NL-DoD)

    ISS Expedition Duration:

    March 2011 - October 2013

    Expeditions Assigned


    Previous ISS Missions

    MHTEX flew as Two Phase Flow (TPF) with different heat pump and capillary loop configurations on STS-85.
    CANARY is modified from a version (FLAPS) that flew as a sensor on Falcon-Sat 3 and is scheduled to fly on Falcon-Sat 5 (WISPERS).
    This is the first mission for STP-H3-DISC.

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    Experiment Description

    Research Overview

    • The primary goal of Space Test Program - Houston 3 - Digital Imaging Star Camera (STP-H3-DISC) is to provide a flight demonstration of a small, low power star camera capable of providing attitude (or orientation) knowledge within 0.02 degrees or better.

    • The attitude information is fundamental for spacecraft control and is used to point the solar arrays toward the sun or to identify the precise geo-position of objects on the Earth.

    • The development of such a control and science-enabling technology is critical for space-flight missions on small spacecraft that cannot afford the mass, power or cost of traditional star trackers, but require better pointing knowledge than current small satellite technologies can provide.


    Accurate precision pointing knowledge is a critical mission requirement for many scientific and operational payloads in space. A low Size Weight And Power (SWAP) pointing sensor, such as DISC, will provide a science enabling technology on pico- and nano-satellite platforms for payloads with stringent pointing requirements.

    The goals of the DISC program are to:

    • 1) Develop concepts and a prototype for a low SWAP pointing system with 0.02 degrees resolution or better.

    • 2) Develop processing algorithms to identify and register stellar sources. Coarse attitude solutions are used to identify the specific region of the sky of the star image. The data from the set of star images will then be used to identify and reduce the error in the star camera vector measurements.

    • 3) Space-qualify the prototype unit and demonstrate performance capabilities. These goals are coupled with the primary research objective of the DISC investigation which is to successfully acquire, downlink and calculate an accurate aspect solution from the DISC image. Performance characterization of the DISC camera, including a determination of the limiting magnitude, optimal integration times, and susceptibility to scattered light are of particular interest to the research team. A series of DISC images acquired over a span of a few minutes to one orbit may also be used to investigate the on-orbit dynamics of the ELC 3 on the ISS.

    The STP-H3 flight provides a proof of concept for a new low-cost, cutting-edge technology, sensing platform that strives to provide an enhanced pointing capability for nano- and pico- satellite busses. The potential benefit to the space community is the ability to provide operational data from small low cost platform versus traditional large integrated platforms such as Defense Meteorological Satellite Program (DMSP) and National Polar-orbiting Operational Environmental Satellite System (NPOESS) is significant. This technology represents a key transition from large, high cost, long-timescale programs to small, low-cost, rapid response science enabling sensing platforms.

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    Space Applications

    The thermal control, attitude knowledge, and environmental sensing technologies under investigation offer a potential increase in efficiency and decrease in cost in future spacecraft design and development efforts.

    Earth Applications

    One class of spacecraft that these technologies may be applied to include those incorporating earth-bound communication. The potential improvements these demonstrators will provide are in the creation of more robust and capable satellites that are controlled by ground systems.

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    Operational Requirements

    The STP-H3 hardware complement was installed with the SSRMS and activated via ground based commands. Instrument health, status and operational data will be downlinked via standard ISS 1553 communications protocols.

    Operational Protocols

    DISC uses innovative technologies and instruments to record deep space images of star fields. The data will be downlinked and processed to calculate an attitude vector. The data will then be correlated with other ISS star trackers. DISC incorporates a bi-static shutter system to avoid over-exposure via direct sunlight. Operational precautions must be made to assure that DISC does not acquire images when pointing near the sun.

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    Results/More Information

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    Related Websites

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    image Concept drawing of STP-H3.
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    image Digital Imaging Star Camera (DISC) flight unit.
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    Information provided by the investigation team to the ISS Program Scientist's Office.
    If updates are needed to the summary please contact JSC-ISS-Program-Science-Group. For other general questions regarding space station research and technology, please feel free to call our help line at 281-244-6187 or e-mail at JSC-ISS-Payloads-Helpline.