COLORADO SPRINGS, Colo. — The Air Force is aiming to slash four years off the procurement of the next generation of missile warning satellites, reducing the time to develop and field the first satellite from nine years to five years, the service’s top civilian announced Tuesday.

During the fiscal year 2019 budget release, the Air Force announced its plans to cancel the 7th and 8th satellites in the Space Based Infrared System constellation, or SBIRS, which provides early-warning capability to the nation’s missile defense system. Instead, it will transition to a new program called Next Generation Overhead Persistent Infrared.

Air Force Secretary Heather Wilson wants the new satellites to be more survivable and fielded more quickly, and will announce in a speech Tuesday night at Space Symposium that her goal is to shave four years off the program.

“We aren’t going to spend years on an analysis of alternatives. We will drive toward simplicity and use known sensor technology,” she said, according to prepared remarks of her speech. “But the biggest barrier to speed isn’t in industry; it’s in the Pentagon.”

Putting the first satellite on orbit in five years is an aggressive goal, said Will Roper, the service’s top acquisition executive.

However, it’s unclear where the starting post actually is. Roper said the clock will start ticking down “once the program manager has the reins, and the reins means that they have a vendor that they’re working with.” But it’s unclear whether that means when a number of vendors begin prototyping concepts, or when the service makes its final downselect.

“We are going to begin with very focused prototyping, competitive prototyping as opposed to the long analysis,” Roper told reporters ahead of Wilson’s speech. “That shaves time off … increases competition, determines the people who can really build on the schedule, who are the ones that can’t and then you can pare down.”

As far as what the SBIRS follow-on will look like, it’s clear that much is still to be determined and will rely on the results of the prototyping effort and what companies can prove is in the realm of the possible.

Wilson said the service will lean on mature sensors and a common satellite bus to speed up the fielding of the new satellites. The Air Force will also set up a new, still unnamed office, which will report directly to Roper, which will “change the Pentagon rules on how we buy things so that speed is possible.”

Chief of Staff Gen. Dave Goldfein added that the new satellites must also be part of a defendable architecture. That, Wilson said, could mean giving those satellites defensive capabilities, making them more maneuverable or putting more fuel onboard.

Part of that survivability could also involve putting the missile warning satellites in a mix of different orbits.

“We’re not ready to say what we think the right mix is,” Roper said. “Part of moving to prototyping is acknowledging that you’ve got some experimentation and discovery to do. There are benefits to having things in LEO, there are benefits to having things in GEO, there are benefits to having things in highly elliptical orbits.” “We need things that work together to give us a resilient architecture.”

Gen. John Hyten, the head of U.S. Strategic Command, was one of the biggest critics of the original SBIRS follow-on plan. In December, he said it was “ridiculous” that it would take until 2029 to field a baseline capability.

However, on Tuesday afternoon he told reporters he was “excited” about the Air Force’s new trajectory with Next Generation Overhead Persistent Infrared.

“I made a little bit of an overstatement to make a point — saying that I wouldn’t support the development of any more big, fat, juicy targets,” he said. “I need a flexible warfighting capability to meet the requirements I have.”