On 17 March 1958, the three-stage launch vehicle placed Vanguard into a 654 km × 3,969 km (406 mi × 2,466 mi), 134.27-minute elliptical orbit at 34.25°. Original estimates had the orbit lasting for 2,000 years, but it was discovered that solar and during high levels of solar activity produced significant perturbations in the height of the satellite, which caused a significant decrease in its expected lifetime to about 240 years. Vanguard 1 transmitted its signals for.
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