Defense Intelligence Reference Document Laser Lightcraft Nanosatellites

UNCLASSIFIED/ /1"91t 91"1"1!111it l!l!il! 811L¥
push broom scanning mode for complete Earth coverage rather than only sampling
coverage.
The constellation/array implementation is similar to that of the preceding concept (High
Resolution Surface Sampling Radiometry section), except that tethers hold a receiving
array that must be 2 km long to obtain the 1,200 km instantaneous swath width with a
resolution of 100 m. It consists of a 2 km long focal surface with 12,000 printed
dipoles, shaped into a focal surface by gravity gradient forces balanced against
magnetic forces from a superconducting conductor around its periphery, acting on a
piezoelectric, electron beam-shaped, adaptive membrane substrate. The large antenna
is formed by a swarm of tiny elements making up the lens of a space-fed array.
The antenna is a 4 km x 6 km diameter, sparse, self-cohering array formed from
12,000 picosats weighing 23 grams each, rotating in relative coordinates in a plane
around a central orbit point. The picosats are similar to those of the preceding concept
(High Resolution Surface Sampling Radiometry section). Their locations are initially
selected to lie in a plane, and their spacings are pseudorandom to minimize the
sidelobe levels, with each picosat designed to loosely stationkeep inside a box 10 m on
a side. The relative positions of these picosat elements changes slowly, and only small
and infrequent stationkeeping propulsive maneuvers are needed for constellation
maintenance.
The effective collecting aperture of the array is the sum of those of the picosats, and in
this concept, equal to that of an equivalent 6 m diameter antenna at 2 GHz. However,
the coverage spot diameter is set by the total aperture diameter of 4 km x 6 km, and
thus is 100 m at 2 GHz from a 4,000 km orbit. Five constellation/arrays would produce
100% global coverage with 5 hour revisit for time critical measurements. The entire
constellation weighs 3,000 kg, but that could be reduced in the future to 30 kg if
Buckytubes are used to construct the system.
ROTATING NANOSAT SWARM DISTRIBUTED RADAR
An extremely powerful space-based radar, this concept would allow detection of most
air, land, sea, and space targets, as well as many "low observable" targets anywhere,
with one or a few constellations in GEO. A large, sparse array antenna using a swarm
of nanosats creates a space-based radar system. The constellation/array
implementation is similar to that of the preceding rotating swarm concepts, except that
it generates and radiates extremely large peak and average powers, and given the
generally high angles of viewing can detect and track many air, space, and surface
targets from GEO.
The constellation is composed of 10,000 nanosats that are self-contained repeater
spacecraft weighing about 1 kg each. Each nanosat receives the ground signal,
digitizes, delays, and retransmits it, causing it to arrive at the feeds at the same time
as a direct ray through the center of the array. The time delay of each nanosat is self
computed based on its location in the swarm, as measured by a local DGPS-like
navigation signal, to compensate for its deviation from its assigned ideal location.
Commands for beam sweep delays are superimposed on the time delays of each
nanosat. Each nanosat generates 10 W of average power and 10 kW peak power at
UNCLASSIFIED/ ,'1'81l 81'1'Uil,t.k Wlili liUlklC
39