ATS-4
 ATS satellite prototype | |
| Mission type | WeatherSatellite |
|---|---|
| Operator | NASA |
| COSPAR ID | 1968-068A |
| SATCATno. | 03344 |
| Mission duration | 38 days |
| Spacecraft properties | |
| Bus | HS-306[1] |
| Manufacturer | Hughes Aircraft |
| Launch mass | 305 kilograms (672 lb)[2] |
| Power | 350 W (peak)[3] |
| Start of mission | |
| Launch date | August 10, 1968, 22:33:00UTC[4] |
| Rocket | Atlas SLV-3C Centaur-D |
| Launch site | Cape Canaveral[2]LC-36A[4] |
| End of mission | |
| Disposal | August 10, 1968 |
| Decay date | October 17, 1968[5] |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | LEO |
| Eccentricity | 0.042372[4] |
| Perigee altitude | 185.99 kilometres (115.57 mi)[4] |
| Apogee altitude | 766.89 kilometres (476.52 mi)[4] |
| Inclination | 29.141º[4] |
| Period | 94.131 minutes[4] |
ATS-4(Applications Technology Satellite) also known asATS-Dwas acommunications satellitelaunched byNASAon August 10, 1968[5]fromCape Canaveralthrough anAtlas-Centaurrocket.[2]
Objectives
[edit]The objective of ATS-4 was to investigate the possibilities of a gravity gradient stabilization system (the method of stabilizing artificial satellites).[5]
Features
[edit]The satellite has a cylindrical shape with a 142-centimetre (56 in) diameter and 183-centimetre (72 in) height (about 360 centimetres (140 in) considering the motor cover) with the surface covered bysolar panels,and stabilized bygravitygradient.
Instruments
[edit]A total of four experiments were conducted during the mission:
- Microwave Transponder
- GravityGradientStabilization
- Image Orthicon (Day/Night) Camera
- Ion Thruster
Mission
[edit]The Atlas and Centaur stages performed satisfactorily and placed the Centaur/ATS-4 in anellipticalparkingorbit, the Centaur stage, however, failed to re-ignite after a 61-minute coast. The failure was determined to be caused freezing of the hydrogen peroxide supply lines to the Centaur engines.[4]Highatmospheric dragdue to the low altitude of the achieved orbit precipitated theorbital decayof the spacecraft, yet, still achieved good results in some of the experiments. The primary objective to put a spacecraft stabilized by gravity gradient in orbit was not reached. The satellite reentered the atmosphere on 17 October 1968.[5]
References
[edit]- ^Hughes Aircraft Company Space and Communications Group(1972-09-29)."Tracking and data relay satellite system configuration and tradeoff study. Volume 5: TDRS spacecraft design, part 1"(PDF).NTRS - NASA Technical Reports Server.El Segundo, California: NASA. p. 269.Archived(PDF)from the original on 22 April 2021.Retrieved22 April2021.
- ^abcBell, Ed."1968-068A".NASA Space Science Data Coordinated Archive.NASA.Archivedfrom the original on 2021-01-21.Retrieved22 April2021.
- ^Fairchild Hiller Space Systems Division(1 December 1966)."ATS-4 study program, volume 4 Final report"(PDF).NTRS - NASA Technical Reports Server.Germantown, Maryland: NASA. p. 64.Archived(PDF)from the original on 22 April 2021.Retrieved22 April2021.
- ^abcdefghLewis Research Center(1972-05-01)."Atlas-Centaur AC-17 performance for applications technology satellite ATS-D mission"(PDF).NTRS - NASA Technical Reports Server.Cleveland, Ohio: NASA.Archived(PDF)from the original on 2021-04-22.Retrieved22 April2021.
- ^abcdGarner, Robert (2010-01-22)."ATS".Goddard Space Flight Center.Greenbelt, MD: NASA.Archivedfrom the original on 2021-02-26.Retrieved22 April2021.
ATS-4 was to investigate the possibilities of a gravity gradient stabilization system. A launch vehicle failure stranded ATS-4 in a much lower than planned orbit, making the satellite nearly useless. Despite this, NASA engineers successfully turned on several of the experiments to collect as much information as possible during the craft's short life. The low orbit and resulting atmospheric drag caused ATS-4 to re-enter Earth's atmosphere and break apart on Oct. 17, 1968.