The Atlas, Delta, and Titan II boosters are generally considered medium-lift launch vehicles because of their payload capacity, though the distinction is somewhat arbitrary. Generally speaking, a medium launch vehicle can place a payload of 360 to 6800 kilograms into a 185-kilometer polar orbit. Small launch vehicles such as Pegasus and Taurus can lift about 270 to 900 kilograms, and a heavy-lift vehicle such as a Titan IV or space shuttle can deliver more than 14,500 kilograms to the same orbit. Medium launch vehicles generally cost about a third or less than a heavy-lift Titan III/IV. DMSP, GPS, DSCS, and most research spacecraft are sized to meet the mass, height, and diameter specifications for a medium-class booster. The process of payload/booster integration is decided in early studies before final design. Given the international competition among launch vehicle providers, this becomes a large effort for spacecraft designers.