Ariel 6

 1979-047A

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The final satellite in the Ariel series, UK 6, was built by Marconi-MSDS/Portsmouth for SRC, with BAe-Dyn/Bristol building the structure. Its main experiment was the Bristol university cosmic ray experiment, which was designed to detect heavy energetic nuclei. The 154 kg satellite was 1.31m long, 0.70m diameter. It was controlled from the SRC Appleton Lab's Ditton Park (Slough) site, using NASA's Winkfield ground station, and managed by AL/Slough. In summer 1980 control was moved to RAL/Chilton.

Ariel 6 was launched in Jun 1979. It operated until Feb 1982, but had problems with some of its systems, including interference from Soviet radar signals affecting the high voltage supplies, and the X-ray experiments were largely unsuccessful. The orbit passed through the SAA, creating further difficulties. Thermal control and battery charging problems also reduced observing time, and the satellite had an unexpectedly high coning angle which modulated the X-ray signals in a way that was difficult to calibrate.

The MSSL LE telescope used four grazing incidence paraboloidal mirrors each with a proportional counter. The LUX variability study used four PCs with a collimator; Ariel 5 couldn't detect varability in less than one orbit, so the Ariel 6 experiment was designed to study shorter variations.

Mass St 4 plus UK6 was 477 kg full 202 kg empty; St 4 is usually 306f 31 em, leaving 17 kg unaccounted. Size was 0.70m dia 2.74m span 1.31m high.

In late Sep 1979 the Leicester experiment on Ariel 6 detected an increase in the local particle background over the coast of South Africa, coincident with the suspected South African nuclear test.

Ariel 6
Date	Time	Event	Orbit
1979 Jun 2	2326	Launch by Scout D-1	WI
		T+1:20 St 1 burnout	-6275 x 75 x 48.4
		T+1:26 St 1 sep
		T+1:33 St 2 burn 38s
		T+2:05 St 2 burnout
		T+2:10 Fairing sep 152 km	-5755 x 221 x 52.2
		T+2:11 St 2 sep
		T+2:11 St 3 burn
		T+2:45 St 3 burnout	-4257 x 634 x 53.3
	2336	T+10:19 Spinup
		T+10:21 St 3 sep	-4256 x 628 x 53.3
	2336	T+10:27 St 4 burn 34s
	2337	T+11:01 St 4 burnout
	2338	T+12:20 Despin (motors?)
		T+12:20 Booms deploy
	2341	T+15:20 St 4 sep	97.2 600 x 654 x 55.0
	2349	T+23:19 St 3 impact at 2.6N 46.6W
1982 Feb 24		End of operations

Payload:

• Cosmic ray expt (Bristol/Fowler) Z=0 to 130; 0.74m dia scintillator

• Low energy x-ray telescope and proportional counters 0.1-2.0keV, high time resolution, MSSL/Boyd

• Variable cosmic X ray source expt, 2-50keV, Leicester/Pounds

• RAE solar cell techology expt