VSE (Delta-180, DM-43)

VSE (Delta-180) [SDIO]

VSE-PAS (Delta-180) [SDIO]

The VSE (Vector Sum Experiment) or Delta 180 was the first of the Delta / SDI missions. It involved the placement of a Delta second stage and a Payload Assist System (PAS) in two 120-nautical-mile-high time-synchronous orbits with slightly different inclinations. The overall objectives of the mission were to:

• gather optical spectral data from rocket propulsion sources and
• confirm guidance and navigation algorithms for interception.

A Delta-3920 vehicle was used for the booster, and the countdown proceeded smoothly to Delta 180's lift-off from Pad 17B at 1508:01Z on 5 September 1986.

The extreme complex mission, which costed $150 million, lasted only 205 minutes.

From the initial orbit the prime payload was release. It was mounted on am McDonnell Douglas PAS (Payload Assist System) platform, powered by a TR-201 engine. It featured advanced IR and UV sensors and a mast mounted LIDAR and a Hughes Phoenix AIM-54C+ based Radar seeker. The payload maneuvered to a distance of 200 km from the second stage target and conducted various manoeuvres. At 92 minutes a Aries rocket launch from White Sands was observed by the IR sensors. Finally after 205 minutes the satellite was maneuvered to a head on collision with the second stage a relative velocity of 10450 km/h. The impact and the flash of the self destruction charge to ensure complete destruction of the classified instruments was observed from Kwajalein.

The second stage of the Delta launch vehicle was equipped with a number of forward looking sensors to assess rocket plumes of the main payload and aft pointing sensors to assess its own plume.