Since its inception in 1985, the LACE Program encountered many changes. These changes were largely driven by the Strategic Defense Initiative Organization's (SDIO) desire to take advantage of the latest technology as well as a need to adapt to budgetary changes. As a result, the LACE Program faced many challenges over the years.
The project began as a simple, spaceborne target with a single sensor to characterize a laser beam emitted from a ground-based laser site. Next, the Program was expanded to a few sensors to characterize the laser beam and modify NASA's Long Duration Exposure Facility (LDEF) as a host vehicle. With the Challenger accident and the ensuing hiatus in shuttle launches, the shuttle-launched LDEF was no longer available to carry the LACE target board into space. Therefore, in June 1986, it was decided that LACE would be a full satellite itself instead of a set of sensors on a host satellite.
By 1987, the simple, spaceborne target had evolved into three separate sensor arrays with a total of 210 sensors capable of characterizing ground-based laser beams with continuous wave or pulsed emission in the visible, UV, and IR bands (see LACE-SAS). Also, SDIO began discussing the addition of an instrument to take video images of rocket plumes by their UV emission.
By April 1987, a request for proposals for the Ultraviolet Plume Instrument (UVPI) had been sent out. Based on the responses, a decision was made to add the UVPI to the LACE satellite (see LACE-UVPI).
Over the next several months, the launch vehicle was changed from a Delta rocket to an Atlas, to a Titan, and then back to a Delta. At this point the Air Force's Relay Mirror Experiment satellite was added to the LACE satellite for launch. Each major change required a re-evaluation of all of the concepts and decisions that had preceded it.
On 14 February 1990, the LACE satellite was launched from Cape Canaveral. The "simple, spaceborne target" proved that techniques to compensate for atmospheric distortion of laser beams actually work. The UVPI succeeded on all four of its opportunities to make video images of the UV emission from rocket plumes.
Donald M. Horan, Ph. D.
Chief Scientist
Director of Operations
October 1991