RELAY 1 (A-15)

About This Satellite

Relay 1 launched on December 13, 1962 aboard a Thor-Delta into an elliptical orbit. Built by RCA for NASA, it tested the retransmission of television, telephone, and digital signals. NASA's history records a November 1963 transpacific television demonstration between Japan and the United States, part of the experiments that preceded routine international satellite communications.

A spare transponder rescued the early mission

The spacecraft initially suffered an abnormal battery drain traced to a voltage regulator in one transponder. Operators used a second transponder as a backup, allowing the mission to proceed. This is a concrete example of onboard redundancy: success depended on which communications hardware remained usable, not simply on whether the spacecraft had reached its planned orbit.

Meeting the objectives did not end the transmissions

NASA records that Relay 1 had met its objectives by March 1963. It later failed to respond to shutdown commands in December that year and continued relaying until February 1965. Those dates distinguish the planned experiment, command behaviour, and final communications period; none establishes a present-day usable relay service.

Mission reference: NASA Historical Data Book: Relay project and Relay 1 mission history. Editorial review: 2026-09-14.

An active relay is more than a reflecting object

NASA's communications history distinguishes active satellites, which amplify received signals onboard, from passive experiments such as Echo, which reflected radio energy. Relay belonged to the active approach. Its ground stations and transponder formed a communications link; merely having a reflective object above the horizon would not reproduce that function. This helps explain why a working spacecraft payload mattered alongside orbital visibility.

Reference: NASA: active repeaters, passive reflectors and early communications systems.

Solar cells were also part of a radiation experiment

NASA's Relay I radiation-effects report documents monitoring solar-cell damage through measurements of short-circuit current. The mission therefore provided engineering evidence about the orbital radiation environment as well as communications demonstrations. A current measurement from a test cell is an electrical diagnostic, not a photograph of a radiation belt or a direct measure of the quality of a television transmission.

Reference: NASA NTRS: The Relay I Radiation Effects Experiment, 1966.

Reading this orbital snapshot

Based on TLE epoch: 2026-09-05. Estimated altitude ranges from 1,329 km at perigee to 7,428 km at apogee, a difference of 6,099 km. The orbital period is about 185.0 minutes. Eccentricity 0.28348 shows why a single altitude cannot describe the whole path. In a two-body approximation, perigee speed is 1.79 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 47.52 degrees implies approximate geocentric ground-track limits of 47.5 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.

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 503 · GCAT: S00503 (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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