Low earth orbit (LEO) satellites still have to deal with air resistance even though they are thin at an altitude of thousands of kilometers from the earth's surface. From time to time it has to be re-raised to the original orbit using the fuel carried. Over time when it runs out, the satellite is no longer able to maintain orbit and burns up
The United States Space Force (USSF) expressed interest in building a system that would allow satellites in space to be refueled and also perform maintenance when needed.
For this purpose, the USSF has chosen the Passive Refueling Module (PRM) designed by Northrop Grumman as the standard for military satellites and spacecraft that will function as refueling stations. Northrop Grumman was also entrusted with developing the Geosynchronous Auxiliary Support Tanker (GAS-T) which will carry out this task in the future. GAS-T is a robot that can perform the above tasks without a human crew.
With GAS-T older satellites can still be used and this can save hundreds of millions in the cost of making new satellites and launching them instead. From a military point of view, strategic assets will be able to continue to function when needed.