AFRL's lunar patrol satellite, CHPS

AFRL’s newly-named Oracle satellite will monitor space between the Moon and the Earth. (AFRL)

WASHINGTON — The Air Force Research Laboratory’s ground-breaking effort to develop and launch an experimental cislunar monitoring satellite, now called Oracle, faces a number of hurdles — from simply ensuring the satellite can stay in its complex orbit between the Earth and Moon to working out the “math” for understanding what its cameras are actually seeing, according to AFRL officials.

“There’s a lot of challenges in this mission,” Lt. Col. David Johnson, chief of AFRL’s space experiments and evaluation division, told Breaking Defense in a recent joint interview with Oracle Program Manager Michael Lopez.

AFRL initiated its project to prototype a satellite, originally called Cislunar Highway Patrol Satellite (CHPS), back in 2020 designed to track other satellites, spacecraft and debris in an area of space expected to become more crowded over the next couple of decades. The lab announced on Nov. 10 the name change to Oracle, in tandem with a $72 million contract award to Colorado startup Advanced Space LLC with partners General Atomics and Leidos.

Space Force officials for several years have been touting the need for maintaining space domain awareness in cislunar space as US and allied commercial actors, and more importantly peer competitors, press forward with plans to exploit the region — especially China.

Should all go to plan, Oracle would occupy a strategic spot in space that would allow it to see the comings and goings in cislunar space better than Earth-bound telescopes or Earth-orbiting satellites, according to AFLR officials.

Fly Me To The Moon — And Keep Me There

Earth-Moon Lagrange points, NASA image

Earth-Moon Lagrange points (NASA image)

One big challenge for the lab and its industry teammates includes figuring out how to keep the satellite in a “halo” orbit around the L1 Lagrange point between the Earth and the Moon, Johnson said, noting that to his knowledge this is something that no other US satellite has done before. “That doesn’t automatically mean there hasn’t been any, it just means I’m not aware of it,” he caveated.

Lagrange points are orbital positions where the space objects are more or less balanced by the gravitational pulls of two larger bodies, such as the Earth and the Moon or the Earth and the Sun. There are five such points in any orbital three-body system.

But getting the satellite to L1, and to stay there, can be difficult.

“Part of the challenge of Oracle is understanding and figuring out how do we handle working in that space?” Johnson elaborated. “How do we get out there, what’s our orbit gonna look like, what’s our station-keeping once we’re at the Lagrange point? All of those are technical challenges that our team needs to work to address and plan over the next few years in parallel while we build the satellite.”

AFRL hopes to be able to launch Oracle in late 2025, but Lopez noted that the lab is dependent on the Defense Department’s Space Test Program to obtain a launch vehicle. This means that not only is the launch date unclear, the actual trajectory the satellite will take to reach L1 remains in flux — the satellite could hitch a ride alongside another satellite headed to geosynchronous orbit around the Earth, or perhaps even with a NASA rocket headed for the Moon.

“There’s a few options,” Lopez said. “NASA CAPSTONE mission used a ballistic lunar transfer version, which is something that we’re interested in doing so it’d cut the travel time by a few months.”

Advanced Space also operates NASA’s CAPSTONE, for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment, launched in June as part of the agency’s Artemis human space exploration program. CAPSTONE will be testing how to station-keep in the rectilinear orbit around the L1 and L2 Lagrange points where the agency hopes to operate its future Gateway space station for human and unmanned deep space exploration.

No matter what initial orbit Oracle gets lofted to, it will be using AFRL’s own “green” fuel, called Advanced Spacecraft Energetic Non-Toxic, or ASCENT, to propel itself to and around L1, Johnson said.

“Green propellant provides you more efficiency with less risk than the traditional propellants, and so this is a great opportunity,” he said. “We can not only get this critical mission done out in the system, but basically we can also utilize the latest in green propellants as well and help advance that technology.”

Seeing Through The Dark

Screen Shot 2022-11-23 at 12.49.02 PM

Cislunar space (AFRL YouTube Video)

Johnson explained that AFRL picked L1 because an imaging satellite stationed there can “look backwards towards the Earth” to find potential threats — such as adversary spacecraft and missiles, or dangerous space debris that could harm NASA and commercial spacecraft working in the cislunar region — without being blinded by the Sun. Current telescopes on Earth or in the Earth’s own orbit oftentimes are facing the Sun’s glare —  into what is called the cislunar exclusion zone, or jokingly, “the cone of shame” — for long periods of time.

If something were moving in that large cone of space, we would be completely unaware of it until such time it got close enough to the Earth and it’s no longer in that sort of bright zone,” he said

AFRL has come up with a preliminary design for the imaging system, being built by Leidos, using a wide field of view electro-optical (visible light) camera for detecting objects, a narrow field of view for keeping custody of detected objects of interest, Lopez said.

But the hardest technical nut to crack, Johnson said, will be “all the software” and “math” required to enable that camera system to autonomously process what it is “seeing” in the vast volume of space between the Earth and the Moon.

“I think the the algorithmic challenges associated with space situational awareness from cislunar space is one of the biggest challenges that we have to overcome,” he said. “Part of the goal here with this system would also be to have a level of autonomy on boards, capable of doing a lot of things itself to help reduce the dependency on the ground.”

Oracle has to be able not just to detect space objects, but also discriminate targets of interest from what is currently an unfamiliar background for space imagery analysts filled with myriad stars and a growing number of spacecraft, he explained.

“From the Earth, it’s pretty easy to understand what things are doing … You have a good frame of reference, how the Earth rotates, [and] you understand how a point in space is moving,” Johnson said. But at L1, the spacecraft will need “completely different algorithms to understand when I’m looking at a dot out there and that dot is moving, is that a star that I’m seeing as I move or, no?”

Lopez said that the current contract covers 18 months to critical design review, “and then we have the options for the rest of the program — so, assembly, integration, testing, launch and then operations.”

And AFRL already is working with the Space Force to put together an operations team, mostly likely co-located with the lab’s site at Kirtland AFB in New Mexico where the Oracle project is now based, Johnson said.

“I think the most likely scenario is this will be flown out of the the operation centers here at Kirtland, along with the Space Systems Command community but, again, those conversations are still ongoing as well,” he said.

The plan is for the experiment to run two years, and then hopefully AFRL can pass the satellite over to a Space Force unit — for example, Space Training and Readiness Command — to make use of until its end of life, he added.