The Kree Reapers Satellite was a containment vessel that kept the Kree Reapers in stasis as it orbited the Solar System. It also doubled as transportation, designed to travel to Earth when the Kree Orb is activated.
After creating the Inhumans, the Kree Reapers designed the Kree Orb to be activated as the signal should something go wrong with their experiment. Two Kree Reapers remained in stasis in the Satellite, orbiting through the Solar System and ready to come back to the planet at any moment.
Thousands of years later, Hive ultimately activated the Kree Orb and the Satellite dove onto Earth, crashing in Union City and releasing the Kree Reapers to hunt down the Inhumans. While on site, S.H.I.E.L.D. found the remnants of the Satellite as well as footprints from the Kree Reapers.
The Kree Reapers Satellite was designed as an small ellipsoid spaceship. It was programmed to rapidly head back to Earth as soon as it would receive a signal from the Kree Orb, orbiting through the Solar System during thousands of year in the meantime. Additionally, the Satellite was equipped with stasis equipment enabling two Kree Reapers to remain in suspended animation during this whole time span.