 Ariel 4. | |
| Names | Ariel4, UK 4 |
|---|---|
| Mission type | Ionospheric |
| Operator | SERC /NASA |
| COSPAR ID | 1971-109A |
| SATCATno. | 5675 |
| Mission duration | 1 year (design life)[1] |
| Spacecraft properties | |
| Manufacturer | BAC |
| Launch mass | 99.5 kilograms (219 lb) |
| Start of mission | |
| Launch date | 11 December 1971, 20:47:01 (1971-12-11UTC20:47:01Z) UTC |
| Rocket | Scout B-1-F S183C |
| Launch site | Vandenberg SLC-5 |
| Contractor | NASA |
| End of mission | |
| Decay date | 12 December 1978 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Eccentricity | 0.00795 |
| Perigee altitude | 473 kilometres (294 mi) |
| Apogee altitude | 590 kilometres (370 mi) |
| Inclination | 82.9 degrees |
| Period | 95.26 minutes |
| Epoch | 10 January 1972[2] |
Ariel 4, known pre-launch asUK 4, was a Britishionospheric researchsatellite, which was operated by theScience and Engineering Research Council. It was launched 11 December 1971, aboard an AmericanScout rocket. Experiments were designed to meet one scientific objective, making it the first mission-oriented satellite for the UK. It was also the first satellite in theAriel programme to contain an American experiment. Ariel 4 decayed from orbit on 12 December 1978
Ariel 4 leveraged both the design and hardware ofAriel 3 to reduce costs. Ariel 4 used pieces of its predecessor's flight backup unit and spare parts. The satellite cost about 1.25 million pounds.[3]
British Aircraft Corporation was the prime contractor.[4] Ariel 4 had a launch mass of 101 kilograms (223 lb).[3] It was the first satellite in theAriel programme to be able to perform attitude maneuvers.[5]
It was the first satellite of the Ariel programme to have a mission-orientated payload, where all of the experiments are designed to research one scientific objective. The scientific objective was to "...study the interaction between high energy charged particles and electromagnetic radiation in the upper ionsphere and magnetosphere.[6] Three of the five experiments on Ariel 3 were to determine a single scientific objective, so those three were improved for use on Ariel 4 and an additional experiment was added.[7]
Experiments accounted for 18.5 kilograms (41 lb) of the spacecraft's mass.[3]
It was also the first in the program to carry an American experiment.[6]
The launch of Ariel 4 occurred at 20:47:01 GMT on 11 December 1971, fromSpace Launch Complex 5 at theVandenberg Air Force Base.[1] It was conducted byNASA, using aScout B-1 rocket.[8]
Ariel 4 was placed into alow Earth orbit, with a perigee of 473 kilometres (294 mi), an apogee of 590 kilometres (370 mi), 82.9 degrees ofinclination and anorbital period of 95.3 minutes as of 10 January 1972. It decayed from orbit on 12 December 1978.[2]
