LES-3
USAF | |
COSPAR ID | 1965-108D |
---|---|
SATCAT no. | 01941 |
Spacecraft properties | |
Manufacturer | Lincoln Laboratory |
Launch mass | 16 kg (35 lb)[1] |
Start of mission | |
Launch date | 21 December 1965, 14:00:01 |
Rocket | Cape Canaveral LC41 |
End of mission | |
Last contact | Late summer 1967 |
Decay date | 6 April 1968 |
Orbital parameters | |
Reference system | Geocentric |
Regime | Highly elliptical |
Eccentricity | 0.71486 |
Perigee altitude | 195 km (121 mi) |
Apogee altitude | 33,177.00 km (20,615.23 mi) |
Inclination | 26.4° |
Period | 581.80 minutes[1] |
Epoch | 21 December 1965 15:36:00 |
Lincoln Experimental Satellite 3, also known as LES-3, was a
Background
After the successful development and deployment of
These experimental solutions were deployed in a series of nine spacecraft called Lincoln Experimental Satellites (LES). Concurrent with their development, Lincoln also developed the Lincoln Experimental Terminals (LET), ground stations that used interference-resistant signaling techniques that allowed use of communications satellites by up to hundreds of users at a time, mobile or stationary, without involving elaborate systems for synchronization and centralized control.[2]: 81–83
The first experimental solution, demonstrated by LES-1, LES-2, and LES-4, involved communications in the "X-band", the military's SHF (super high frequency) band (225 to 400 MHz)[3]: 9–1 because solid-state equipment allowed for comparatively high output in this band, and also because the band had been previously used by West Ford.[2]: 83–84
The SHF band was not usable for small, tactical deployment as it required large terminals and ground antennas. Lincoln Laboratories thus also explored using the
Spacecraft design
LES-3 was produced quickly using technology from the three LES X-band satellites (-1, -2, and -4). Its primary function was simply to broadcast continuously[2] at a frequency of 232.9 MHz.[3]: 9–27
Polyhedral in shape, and 5 ft (1.5 m) across, the solar powered[4] satellite utilized the frame, power system, and power amplifiers designed for LES-1 and 2 and was similar in appearance to its predecessors.[3]: 9–31 It differed in its omission of optical sensors, and the substitution of a UHF monopole antenna projecting from the top and bottom of the satellite's rectangular top and bottom for LES-1/2's X-band antennas. As a result, LES-3 massed just 16 kilograms (35 lb),[1] about half of its predecessors.[5][6]
The satellite was spin stabilized.[3]: 9–31
Mission and results
LES-3, along with
Despite being placed in an unexpected orbit, spinning at 140 RPM inclined about 15° to the orbital plane (as opposed to perpendicularly, as had been planned), LES-3 functioned properly, providing signals necessary for UHF propagation measurements.[3]: 9–20
The satellite reentered on 6 April 1968,[10] earlier than planned, but not before all desired testing had been successfully completed[3]: 9–20 in late summer 1967.[3]: 9–21
Legacy and status
The LES program continued through nine satellites, culminating in the launch of LES-8 and LES-9 on 14 March 1976.[2]: 88
References
- ^ a b c "LES-3". NASA Space Science Data Coordinated Archive. Retrieved November 27, 2020.
- ^ a b c d e f Andrew J. Butrica, ed. (1997). Beyond the Ionosphere: Fifty Years of Satellite Communication (PDF). Washington D.C.: NASA History Office. Retrieved May 30, 2023.
- ^ a b c d e f g NASA COMPENDIUM OF SATELLITE COMMUNICATIONS PROGRAMS (PDF). Greenbelt, MD: Goddard Spaceflight Center. 1973.
- ^ "Third Titan 3A Vehicle Carries Experimental Comsat into Orbit". Aviation Week and Space Technology. New York: McGraw Hill Publishing Company. February 16, 1965. Retrieved February 16, 2020.
- ^ "LES-1". NASA Space Science Data Coordinated Archive. Retrieved February 17, 2020.
- ^ "LES-2". NASA Space Science Data Coordinated Archive. Retrieved May 2, 2020.
- ^ a b c "Titan 3 Transtage Malfunctions, Fails to Achieve Circular Orbit". Aviation Week and Space Technology. New York: McGraw Hill Publishing Company. December 27, 1965. p. 27. Retrieved November 24, 2020.
- ^ McDowell, Jonathan. "Launch Log". Jonathon's Space Report. Retrieved December 30, 2018.
- ^ a b Powell, Joel W.; Richards, G.R. (1987). "The Orbiting Vehicle Series of Satellites". Journal of the British Interplanetary Society. Vol. 40. London: British Interplanetary Society.
- ^ McDowell, Jonathan. "Satellite Catalog". Jonathon's Space Report. Retrieved February 11, 2020.