As I know, Space Shuttle used the same amount of fuel for every mission. And used OMS for finishing orbit. Then how it is possible that, for example STS-1 which hadn't payload and was in roughly 266km*271km orbit, used same amount of fuel as STS-31 who carried Hubble Telescope (approximately 11t) into orbit of 585km*615km?
If the question refers to the Orbital Maneuvering System (OMS) propellants, as Digger commented, it is based on a false assumption that the same amount of propellant was used for every mission.
Many old Space Shuttle Mission reports are available on the NTRS server. Here are two examples showing the different usages.
Three things I can think of:
- Fuel loaded does not equal fuel used.
The shuttle was loaded with nearly the same amount of fuel for every launch (that being "full tanks"), but that doesn't mean the same amount was consumed. For a normal launch, main engine cut-off would be determined by the orbiter reaching a target velocity. Any fuel remaining in the tank at that point is discarded.
For some missions, there would have been a wider margin between necessary and loaded fuel. For other missions, the margin was very tight.
- Different orbital inclination
Besides altitude, different inclinations require different amounts of fuel to reach. From Florida, any inclination other than 28.5 degrees requires more fuel. For Hubble, STS-31 launched into this most efficient orbit. I don't know what the mission reason was, but the STS-1 orbit was 40 degrees.
- Flight profile
Early shuttle flights flew a "standard insertion" profile, while later flights (including STS-31) flew direct insertion, which was more efficient.
Because the flight profiles were different, comparing OMS burns is difficult, but STS-1 used 161s of OMS and STS-31 used 305s of OMS to reach orbit. So at least some of the difference is there.