You are here

Investigating Satellites Cataloged as Debris (ISCAD)



OBJECTIVE: Develop innovative technology needed to create a one-person-mobile telescope, mount and camera able to track nearly all cataloged space debris, then use it to investigate whether foreign objects assessed to be debris are indeed such.

DESCRIPTION: By 16 June 2015, there were 6,853 satellites listed as orbiting foreign debris in the world-standard United States Satellite Catalog (SatCat), considered a complete list of space objects down to 10 cm[1]. Much debris is released during launch and payload deployment, part is of unknown origin. Some launches disperse large quantities of debris in the transfer to geo-orbit; a nation could easily hide an active payload with the chaff and at apogee circularize its orbit into the geostationary belt with low chance of detection, as noted by some[2]. Knowing the behavior of items in Earth orbit is essential for U.S. Space Situational Awareness (SSA) and Space Object Identification (SOI), for space security. A concern is that many objects have not been examined optically, only tracked by radar. Radar detects metal rods well, but composite or faceted materials can yield a deceptive cross-section and a flawed behavior assessment. The ISCAD approach will visually inspect each "debris" item to ensure that it is behaving like debris, by tumbling and not maneuvering (e.g., any motion requiring powered flight). So far, ground-based telescopic surveys have centered on geostationary orbit; observing low Earth orbit (LEO) space debris is a low priority for the Space Based Space Surveillance and Advanced Technology Risk Reduction spacecraft missions.

This research complements NASA's Meter-Class Autonomous Telescope (MCAT)[3], which will spend much of its time observing debris at low inclination. ISCAD will spend much time observing debris in sun-synchronous orbits, including all foreign debris there. Of an estimated 2,559 sun-synchronous-orbit foreign debris, nearly 1,000 are never visible to MCAT's tropical latitude. A mobile system operating in dark skies at temperate latitudes will be able to capture nearly all of these objects, and can track poorly-lit or low-albedo (approximately 0.1) debris with the proposed design.

The optics must be sufficiently large and the sensor suitably sensitive to detect debris as faint as 17th median magnitude with a sky brightness of 21-plus magnitudes per square-arcsecond (e.g., an 80-cm mirror and EMCCD camera is capable of tracking approximately 5-cm diameter objects, depending on the orbit). Optics can be wide-angle, since some low-orbit debris may have along-track positional uncertainties up to 5 deg. This suggests a design with fast focal ratio, i.e., short focal length relative to aperture size. This does not require a view angle of 5 deg; along-track search-capable software can acquire an object using a narrower (about 0.5 deg) view angle. The mounted telescope should fit within a 7-ft x 7-ft footprint and overhead clearance of <7-1/2 feet in travel mode to be fully transportable. The sensitive high-speed camera must be capable of recording rapid (25 Hz plus) variations, with the camera and mount able to operate in temperatures of 0 deg F. The mount must be capable of tracking an object through the zenith at speeds up to 4 deg/sec, be durable but light enough for self-propulsion, and able to travel up to 100 m from storage to clear horizon on unpaved roads at 7-percent grade, without requiring re-alignment. The Phase I effort will identify design alternatives and, based on the requirements noted herein and development/fabrication cost estimates, determine the best design for the telescope optics, mount, and camera to achieve the requisite tracking goals. The optics and mount will advance technology well beyond present state-of-the-art.

PHASE I: Produce and report telescope-mount-camera design(s) able to track all debris in the SatCat, per the Description, following objects across the entire sky and staying on target through the zenith, across the meridian, and past the celestial pole, uninterrupted. Ensuring stability requires performing finite-element modeling of system vibrations, overshoot, and structural stress.

PHASE II: Use the Phase I design to assemble a prototype telescope, mount, camera, and single computer for controlling both mount and camera, for testing against technical performance parameters identified in Phase I and the Description. The system must be capable of operating in temperatures as low as 0 deg F. Mount control software must acquire satellites without use of an auxiliary telescope. Also, evaluate this product for commercial value to the astronomy community if under $100K production cost.

PHASE III DUAL USE APPLICATIONS: Use a Phase II system for dark-sky "seasonal" studies of debris and compare data to a foreign satellite MCAT subset; study whether items act like debris, reporting anomalous behavior. Explore a mount design patent application & identify a manufacturing partner for lowest cost & maximum reliability.


    • "Satellite Catalog," United States Strategic Command, 16 June 2015.


    • Space Daily 12 April 2015 Russian Space "Russia 'busts satellite spy ring': space commander Oleg Maidanovich quoted from "Space Special Forces" film. Http://


  • MCAT Project Description:


  • TPOC-1: Richard Rast
  • Phone: 505-846-5682
  • Email:
US Flag An Official Website of the United States Government