Vanguard 1
Country: United States of America
Live Position
Ground Track · Last 90 Minutes
Upcoming Passes · Over Your Location
About This Satellite
Vanguard 1 launched on March 17, 1958, becoming the second US satellite and the first satellite to use solar power. It tested the Vanguard launch system and how spacecraft hardware behaved in orbit. This small technology demonstrator belongs to the beginning of spaceflight, not to a modern communications constellation.
Solar cells changed the power question
The mission demonstrated that an orbiting satellite could obtain electrical energy from sunlight instead of depending entirely on a finite battery supply. That was a foundational engineering step. Solar power extends the possible operating life, but does not make transmitters, electronics, or the spacecraft itself immortal.
An enduring object is not an enduring radio service
Vanguard 1 is remembered for surviving in orbit long after its communications ended. The catalog can identify the object without receiving anything from its original transmitter. Treat an orbital prediction here as a tracking product, not as evidence that the solar-powered experiment is still reporting measurements.
Mission reference: NASA: Vanguard 1 and the first solar-powered satellite. Editorial review: .
The useful signal was more than a position beacon
NRL describes the onboard transmitters as sources of engineering and tracking information that also supported measurements of electron content along the satellite-to-station path. This made the radio link part of the investigation: changes in propagation could reveal something about the ionosphere between the endpoints.
Reference: US Naval Research Laboratory: Vanguard engineering and ionospheric measurements.
Why researchers could keep tracking after silence
NRL records the last transmissions in 1964 and describes later ground-based tracking as a way to study orbital disturbances from the atmosphere, Sun, and Moon. Measuring where an object moves and receiving its instrument telemetry are separate activities. The former can remain useful after the latter has ended.
Reference: US Naval Research Laboratory: tracking after the final transmission.
Reading this orbital snapshot
Based on TLE epoch: 2026-09-04. Estimated altitude ranges from 653 km at perigee to 3,818 km at apogee, a difference of 3,165 km. The orbital period is about 132.6 minutes. Eccentricity 0.18371 shows why a single altitude cannot describe the whole path. In a two-body approximation, perigee speed is 1.45 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 34.24 degrees implies approximate geocentric ground-track limits of 34.2 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.
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 5 · GCAT: S00005 (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)