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Atmospheric drag at orbital altitude is caused by frequent collisions of gas molecules with the satellite. It is the major cause of orbital decay for satellites in low Earth orbit. It results in the reduction in the altitude of a satellite's orbit. For the case of Earth, atmospheric drag resulting in satellite re-entry can be described by the ...
As a satellite passes 50 or 60 miles overhead, the mascons pull it forward, back, left, right, or down, the exact direction and magnitude of the tugging depends on the satellite's trajectory. Absent any periodic boosts from onboard rockets to correct the orbit, most satellites released into low lunar orbits (under about 60 miles or 100 km) will ...
Voyager 1 relays messages to NASA’s mission control team after losing contact due to a technical issue. The aging spacecraft is relying on an old radio transmitter.
The satellite network uses a CDMA spread-spectrum technique where the low-bitrate message data is encoded with a high-rate pseudo-random noise (PRN) sequence that is different for each satellite. The receiver must be aware of the PRN codes for each satellite to reconstruct the actual message data.
Strictly speaking, a satellite collision is when two satellites collide while in orbit around a third, much larger body, such as a planet or moon. This definition is typically loosely extended to include collisions between sub-orbital or escape-velocity objects with an object in orbit.
Satellites at altitudes towards the lower bound of MEO can use the "25-year rule" to decelerate with onboard propulsion so that it will fall out of orbit within 25 years, but this provision is only allowed if satellite operators can prove by statistical analysis that there is less than a 1/10,000 chance that the atmospheric reentry will cause ...
Correcting these errors is a significant challenge to improving GPS position accuracy. These effects are smallest when the satellite is directly overhead and become greater for satellites nearer the horizon since the path through the atmosphere is longer (see airmass). Once the receiver's approximate location is known, a mathematical model can ...
Intelsat reports a “total loss”.