Defense Intelligence Reference Document Detection And High Resolution Tracking Of Vehicles At Hypersonic

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European Fireball Network 16 uses cameras at several stations separated by distances of
about 100 km and covering an area of about 1,000,000 km 2 . Fisheye lenses allow each
station to observe the sky every night to monitor meteors and other nebular objects. The
network is operated by the German Aerospace Center (DLR) and the Institute of Planetary
Research in Prague. 17 Other networks include the Meteorite Observation and Recovery
Project (MORP) in Canada and the Prairie Network in the United States; all have been in
operation since the 1960s and 70s.
Another recent meteorite recovery was made when asteroid 2008 TC3 entered the Earth's
atmosphere on 7 October 2008 over Sudan. 18 The meteor's path left a wake that was visible
through dawn. A total of 280 fragments weighing 11 pounds were collected in the Sudanese
desert. The photographic evidence of this hypersonic reentry was interesting. The 4.2-
meter William Herschel Telescope in the Canary Islands optically recorded the spectrum of
this asteroid 2 hours before it burned up in the Earth's atmosphere. This information can be
used to identify the chemical makeup of the surface of the object or of the vaporized
products in its wake. A sequence of photographs taken at 4-second intervals over a period
of about SO seconds provided information on its velocity as it reentered the atmosphere and
its brightness as a function of time.
Although these photographic methods have been applied to meteors, data from the European
Fireball Network and similar camera systems can be used to monitor the flight of hypersonic
aircraft that produce a visible wake through the ionization of air. The photographic methods
described here are limited to nighttime use. Multiple stations recording the same event have
been used to measure both position and velocity of objects moving at hypersonic velocities
through the Earth's atmosphere and the computed trajectories have been used to
successfully predict meteorite impact points on at least two occasions.
Optical systems are constantly monitoring the Earth for possible missile launches. Two KH-11
satellites are constantly in orbit 250 to 500 km above the Earth's surface with multispectral
cameras that resolve objects to within 2 to 3 meters. Big-Bird, at an orbit 160 to 280 km
above the Earth, can take video or photographs with a resolution of 250 mm. The photos
must be sent back to Earth for processing. Close-Look, operating from 130 to 300 km, has
a resolution of 50 to 150 mm. Landsat, with an orbit of 800 km, can transmit multispectral
video of the Earth with a resolution of 20 to 30 meters. The space shuttle, the U-2 aircraft,
and the SR-71 have all been used to provide high-resolution images of objects from high
altitude.
Infrared Detection
Infrared detection of reentry vehicles and ICBMs by satellites has been available since the
early 1960s, with the United States leading the effort through detection of possible missile
launches from the Soviet Union. In addition to RADAR, infrared detection is one of the best
techniques for the detection of hypersonic vehicles.
Theory of Infrared Detection Systems.
All objects emit radiation that is a function of their temperature according to equation 17, the
Stefan-Boltzmann Law: 19
17
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