Why do GPS Satellites Last So Long

Hello,

In the course of research, I noticed that the GPS satellites were
originally designed to function for only three to four years, but many
have had operational lives of ten+ years. Has there ever been a reason
given for this?

Flynfast

flynfast wrote:

Where did you get the "three to four years" figure? Cite please.

The life of a satellite usually depends on the amount of fuel left after it
has been launched and moved into the correct orbit. Most satellites use
less fuel than is budgeted and hence have longer useful lives. Having said
that, 3-4 years sounds very short. Commercial TV and telephony satellites
have lives of 8-12 years, maybe more.

mark.williams@btinternet.com (Mark Williams) wrote in


When you talk of "fuel" and TV satellites, I conclude you're talking
geosynchronous, which the GPS satellites aren't.

--
Bert Hyman | St. Paul, MN | bert@iphouse.com

No, just getting them from position A in the sky where they are launched to
position B where they are useful, and from time to time nudging them to keep
them in the correct orbit. They are powered by solar panels with back up
batteries and small boosters that put them keep them in the correct orbit.
When fuel for those boosters runs out the satellite would not maintain the
same orbit and would have to be replaced.

See http://www.garmin.com/aboutGPS/