ATS-4 explained
| ATS-4 |
| Mission Type: | Weather Satellite |
| Operator: | NASA |
| Cospar Id: | 1968-068A |
| Satcat: | 03344 |
| Mission Duration: | 38 days |
| Spacecraft Bus: | HS-306[1] |
| Manufacturer: | Hughes Aircraft |
| Launch Mass: | 305kg (672lb) |
| Power: | 350 W (peak)[2] |
| Launch Date: | UTC[3] |
| Launch Site: | Cape Canaveral LC-36A |
| Disposal Type: | August 10, 1968 |
| Orbit Reference: | Geocentric |
| Orbit Regime: | LEO |
| Orbit Periapsis: | 185.99km (115.57miles) |
| Orbit Apoapsis: | 766.89km (476.52miles) |
| Orbit Inclination: | 29.141ยบ |
| Orbit Eccentricity: | 0.042372 |
| Orbit Period: | 94.131 minutes |
| Apsis: | gee |
ATS-4 (Applications Technology Satellite) also known as ATS-D was a communications satellite launched by NASA on August 10, 1968[4] from Cape Canaveral through an Atlas-Centaur rocket.[5]
Objectives
The objective of ATS-4 was to investigate the possibilities of a gravity gradient stabilization system (the method of stabilizing artificial satellites).
Features
The satellite has a cylindrical shape with a 142cm (56inches) diameter and 183cm (72inches) height (about considering the motor cover) with the surface covered by solar panels, and stabilized by gravity gradient.
Instruments
A total of four experiments were conducted during the mission:
- Microwave Transponder
- Gravity Gradient Stabilization
- Image Orthicon (Day/Night) Camera
- Ion Thruster
Mission
The Atlas and Centaur stages performed satisfactorily and placed the Centaur/ATS-4 in an elliptical parking orbit, 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. High atmospheric drag due to the low altitude of the achieved orbit precipitated the orbital decay of 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.
External links
Notes and References
- Web site: Hughes Aircraft Company Space and Communications Group . Hughes Aircraft Company . Tracking and data relay satellite system configuration and tradeoff study. Volume 5: TDRS spacecraft design, part 1 . NTRS - NASA Technical Reports Server . NASA . 22 April 2021 . https://web.archive.org/web/20210422113252/https://ntrs.nasa.gov/api/citations/19740002695/downloads/19740002695.pdf . 22 April 2021 . El Segundo, California . 269 . PDF . 1972-09-29 . live.
- Web site: Fairchild Hiller Space Systems Division . Fairchild Aircraft . ATS-4 study program, volume 4 Final report . NTRS - NASA Technical Reports Server . NASA . 22 April 2021 . https://web.archive.org/web/20210422114758/https://ntrs.nasa.gov/api/citations/19670015278/downloads/19670015278.pdf . 22 April 2021 . Germantown, Maryland . 64 . 1 December 1966 . live.
- Web site: Lewis Research Center . Glenn Research Center . Atlas-Centaur AC-17 performance for applications technology satellite ATS-D mission . NTRS - NASA Technical Reports Server . NASA . 22 April 2021 . https://web.archive.org/web/20210422110726/https://ntrs.nasa.gov/api/citations/19720017275/downloads/19720017275.pdf . 2021-04-22 . Cleveland, Ohio . PDF . 1972-05-01 . live.
- Web site: Garner . Robert . ATS . Goddard Space Flight Center . NASA . 22 April 2021 . https://web.archive.org/web/20210226202828/http://www.nasa.gov/centers/goddard/missions/ats.html . 2021-02-26 . Greenbelt, MD . 2010-01-22 . 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. . live.
- Web site: Bell . Ed . 1968-068A . NASA Space Science Data Coordinated Archive . NASA . 22 April 2021 . https://web.archive.org/web/20210121111558/https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1968-068A . 2021-01-21 . live.
