SYNCOM 3

About This Satellite

Syncom 3 launched on August 19, 1964, and demonstrated an orbit that kept the satellite over a selected location on Earth. It advanced beyond Syncom 2's inclined synchronous orbit. The distinction is not simply one spacecraft being higher: the orientation and shape of the orbit are central to the geostationary result.

The Tokyo Olympics became a practical demonstration

In October 1964, Syncom 3 relayed television coverage of the Tokyo Olympic Games to the United States. This provided a memorable use for an otherwise abstract orbital idea: a high-altitude relay could connect widely separated ground facilities across the Pacific.

Stationary in the sky does not mean motionless in space

In the ideal geostationary case, the spacecraft travels around Earth as Earth rotates beneath it. Its apparent fixed position is relative to the rotating surface. This is why a ground antenna can look in one direction while the satellite is still moving along an orbit.

Mission reference: NASA: Syncom 3 launch, geostationary demonstration, and television relay. Editorial review: 2026-09-12.

A fixed direction simplified the receiving end

NASA's communications history contrasts moving-satellite networks, which need tracking and multiple vehicles for continuous service, with a geostationary arrangement using a stationary ground antenna. This explains the engineering attraction of Syncom 3 without implying that a single satellite covers the entire planet or eliminates all signal-propagation limitations.

Reference: NASA: ground-system implications of geostationary communications.

Demonstration and subsequent operations were separate phases

After the NASA research tests, operational control transferred to the US Army in April 1965. That historical handover is not a statement about present service. To understand this record, keep the launch, demonstration, handover, and epoch of the displayed orbital solution as separate events.

Reference: NASA: Syncom 3 transfer after research testing.

Reading this orbital snapshot

Based on TLE epoch: 2026-09-04. Estimated altitude ranges from 35,741 km at perigee to 35,777 km at apogee, a difference of 36 km. The orbital period is about 1434.7 minutes. Eccentricity 0.00043 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 7.15 degrees implies approximate geocentric ground-track limits of 7.2 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 1434.7 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 858 · GCAT: S00858 (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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