The US Air Force is reportedly planning to replace its existing space surveillance (SBSS) Block 10 pathfinder satellite with a three-satellite constellation.

Air Force Space Command commander general John Hyten was quoted by SpaceNews as saying that the air force is likely to use three smaller satellites in low earth orbit to monitor objects in the geosynchronous orbit.

"What do we need from SBSS that we really can’t get anywhere else? We need that real-time, all-weather access.

"You can do that from an equatorial orbit looking up. You don’t need a big satellite to do that. You can do that with small satellites. You can do that fairly affordably."

Built by Boeing Space and Intelligence Systems, the SBSS Block 10 satellite was successfully launched into low-Earth orbit in 2010, onboard Orbital Sciences Minotaur 4 rocket.

"We need that real-time, all-weather access."

Designed to function until 2017, the satellite forms part of a space situational awareness architecture that also features ground-based radar and optical sensors.

The air force apprehends a long capability gap if the life of SBSS cannot be extended beyond 2017. Plans to launch a follow-on programme had to be postponed due to budgetary constraints.

The air force is believed to have asked the Congress for allotment of $251m for the SBSS follow-on programme between 2016 and 2019.

In 2012, the USAF announced plans to award follow-on SBSS satellite contract in 2015 and launch the spacecraft in 2020.

According to industry sources, the launch seems to have been postponed to around 2022, reported Spacenews.

However, Hyten said the USAF still hopes to launch the first of the follow-on satellites before 2021, depending on the budget process.

The USAF had earlier hinted that the Operationally Responsive Space (ORS) 5 satellite would serve as a pathfinder for technologies that are expected to be used in a follow-on to the SBSS programme.

But Hyten said: "It’s not going to fill the gap. Nonetheless, it’s the pathfinder to the follow-on and it will provide us a little bit of insurance when SBSS may die."

Defence Technology