The first of the operational Phase II DSCS systems was launched in 1971. Launch vehicles included Titan III and Titan 34D/IUS. DSCS II has increased communications load capability and transmission strength, and double the lifetime expectancy of the Phase I satellites. DSCS II has an attitude control system for orbital repositioning.
These satellites utilize a despun platform carrying two Earth coverage antennas and two steerable antennas for narrow coverage (NC), and area coverage (AC). The spacecraft are continuously visible to Earth terminals located within 5200 statute miles of the sub-satellite point for elevation angles equal to or greater than 10 degrees Ground command can steer the two-dish antennas on DSCS II satellites and can concentrate the antennas' electronic beams on small areas of the Earth' s surface for intensified coverage (though the dish antennas have limited adaptability in comparison to the newer Phase III satellites).
DSCS-2 spacecraft weigh 1,350 pounds, and have a design life of five years. The spacecraft's cylindrical body is 9 feet in diameter, 6 feet high, and 13 feet high with antennas deployed. Phase II solar arrays generated 535 watts decreasing to 358 watts after five years. The prime contractor was TRW.
The first two DCSC Phase II spacecraft were launched in November 1971. By September 1982, fourteen Phase II satellites had been launched, four were not placed in orbit due to launch vehicle failures and six were operational with varying degrees of availability. The planned launch on a Titan 34D of a fourth DSCS III and the last DSCS II was delayed from mid-1988 to 4 September 1989 to accommodate the 10 May launch of a Chalet to compensate for the 1988 Chalet launch which suffered an upper stage failure.
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