LES 6

About This Satellite

LES-6 combined UHF communications experiments with tests of spacecraft control. Alongside its radio relay, it carried experiments on solar-cell degradation and particle radiation, a pulsed-plasma-thruster system, and automatic longitude stationkeeping. These made it a test platform for operating a spacecraft, not simply another transmitter placed above Earth.

Pointing the spacecraft and holding longitude were separate tasks

MIT lists autonomous attitude control and longitude stationkeeping as distinct LES-6 systems. Attitude describes orientation; stationkeeping concerns the orbit and its location relative to Earth. A successful result in one system therefore does not establish that the other worked as intended.

The experiment belongs to the history of mobile communications

LES-6 helped demonstrate UHF links for small Army, Navy and Air Force terminals, using antenna switching as the spacecraft rotated. MIT records official discontinuation in 2002. Its historical influence on later communications systems does not imply that the catalog object provides an available service today.

Mission reference: MIT Lincoln Laboratory: LES-6 communications and spacecraft-control experiments. Editorial review: 2026-09-15.

A wobble and a weak solar panel affected the radio output

NASA's communications compendium reports a spin-axis offset of about 2.2 degrees and markedly reduced output from one solar panel soon after insertion. The resulting modulation of electrical power also modulated RF output, and automatic attitude control was unusable. An object caught on an antenna was proposed as one explanation, but the cause was not established. It should not be retold as a confirmed debris impact.

Reference: NASA Compendium of Satellite Communications Programs, section 9-23: LES-6 anomalies.

Changing longitude expanded the experimental audience

The compendium describes LES-6 initially being maintained near 93 degrees west. A relocation programme began on July 23, 1969, moving it toward 40 degrees west so European NATO participants could see it; arrival followed in early December. This is a documented change of experimental station, not a current pointing instruction. The same account distinguishes working longitude control from the unsuccessful automatic attitude-control experiment.

Reference: NASA communications compendium: LES-6 stationkeeping and 1969 relocation.

A contemporary report fixes the launch milestone

The US report on space activities in 1968 records LES-6 reaching orbit on September 26 and describes the start of an extensive tactical-communications test programme. It separates this mission from LES-5, launched the previous year, and from the larger TACSAT spacecraft that was still planned. Those different spacecraft should not share a single launch or test history.

Reference: US space activities report 1968: LES-6 launch and tactical communications testing.

Reading this orbital snapshot

Based on TLE epoch: 2026-09-05. Estimated altitude ranges from 35,733 km at perigee to 35,798 km at apogee, a difference of 65 km. The orbital period is about 1435.0 minutes. Eccentricity 0.00077 indicates a nearly circular path. In a two-body approximation, perigee speed is 1.00 times apogee speed. These are mean-element estimates, not instantaneous measurements. Distance per orbit uses an ellipse approximation.

Saved build snapshot. If a valid TLE is retrieved, this explanation and the orbit panel update together. Otherwise this dated snapshot is retained.

Ground track is not sensor coverage

An inclination of 1.69 degrees implies approximate geocentric ground-track limits of 1.7 degrees north and south. This is a prograde orbit, moving in the same general direction as Earth rotation. The plotted line marks the point beneath the object. It does not represent camera coverage, radio reception, or a guaranteed visible pass.

Is it fixed above one longitude?

The snapshot period is 1435.0 minutes. A sidereal day is about 1,436.07 minutes. Height alone does not establish a geostationary orbit: the period must match Earth rotation and the path must be circular and equatorial. This catalog uses a five-minute period tolerance for near-geosynchronous labels; near-geostationary additionally requires inclination at most 1 degree and eccentricity at most 0.01. These are browsing categories, not evidence of station-keeping or a fixed longitude.

Accuracy and missing information

The introductory record describes the build snapshot. The orbital snapshot explanation and orbit panel share any successfully retrieved TLE; check the displayed epoch. Reentered objects retain historical data only. Mission history is not rewritten by TLE updates. TLE/SGP4 positions are predictions and can change after maneuvers or updated observations. The 14-day stale-data cutoff is a display safeguard, not an accuracy guarantee. Local passes are geometric predictions, not a visibility forecast. No verified operator or mission status means unknown, not active. Do not use this catalog for collision avoidance or operational flight decisions.

Catalog sources: CelesTrak SATCAT: NORAD 3431 · GCAT: S03431 (source update 2026 Sep 4 2345:57). Supplementary metadata: SatNOGS DB, retrieved 2026-09-05T12:57:25.375Z. Page assembled 2026-09-15. GCAT phase codes describe trajectory phases, not mission health.

Learn more: TLE data · Perigee and apogee · Ground tracks · JOT (Jewawud Live Orbital Map)

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