It's impossible to give you a precise altitude now because:
* Orbital decay: Over time, Vanguard 1's orbit has been affected by atmospheric drag and other factors, causing it to lower its altitude.
* Unpredictability: Precise tracking of the satellite is no longer done.
However, we can say that it's likely orbiting significantly closer to Earth than its initial altitude of about 650 kilometers.
While we don't have a current exact altitude, we know that Vanguard 1 remains the oldest human-made object still in orbit.
