WASHINGTON — The Pentagon expects to complete the transfer of 24 decommissioned Global Hawk drones this month, advancing its plan to use the systems to support hypersonic testing as soon as 2024.

The RQ-4s are part of the SkyRange program, which aims to use unmanned aircraft to track hypersonic systems during flight tests. The U.S. Department of Defense has relied on ships to perform the mission, but it wants to increase the frequency and flexibility of testing, so the Test Resource Management Center is looking to autonomous airborne systems to take over that role.

The Pentagon is investing in hypersonic research and development efforts across the military services with the goal of fielding weapons and air vehicles that can travel and maneuver at speeds above Mach 5. In its fiscal 2023 budget request, DoD requested nearly $5 billion for hypersonic system development, up from just over $4 billion in the previous year. However, the Pentagon’s infrastructure isn’t sufficient to meet the high demand for flight test support, limiting it to about a dozen airborne demos a year.

George Rumford, TRMC’s acting director, told C4ISRNET in a recent interview that SkyRange is part of a focused effort within the department to pick up its testing cadence. The goal, based on guidance from Principal Director for Hypersonics Mike White, is to develop infrastructure that can support a “drumbeat” of one flight test per week.

“That is a big challenge to us,” Rumford said. “To be able to support 50-plus tests a year, you just can’t keep doing what you’re doing. You’ve got to do something different. And SkyRange is doing something different.”

The benefit of using autonomous aircraft for test support, Rumford said, is flexibility. Flights aren’t limited to a fixed range location because the infrastructure is airborne.

The drones will have a central hub in North Dakota — a UAV and aviation business park called Grand Sky — but the plan is for them to travel to forward operating stations near where a test is needed. Rather than require programs wait in line for a ship to be available or have an event delayed because of maintenance on the vessel, SkyRange is designed to adjust to individual program schedules and needs.

“That means if they want to test in the Pacific, we can go test in the Pacific. If they want to test in the Atlantic, we can test in the Atlantic,” he said. “We can go to where they need to go, which is very different than where it is today. . . . You can’t just reposition a bunch of ships from the Pacific over to the Atlantic in a timely fashion.”

Rumford added that while it can take a ship 21 days to be positioned and outfitted for a flight test, an autonomous aircraft can be ready to support within hours of the activity. The use of unmanned aircraft also improves testing data because the system can fly closer to the hypersonic flight path.

From Global Hawk to Range Hawk

TRMC has been experimenting with the SkyRange concept — in partnership with the Air Force and NASA — for several years, making investments in the sensor and instrumentation technology that will fly on the aircraft and using older-model Global Hawks to demonstrate feasibility.

The program has three Block 10 RQ-4s, one of which is a pre-production aircraft, retrofitted to what it calls Range Hawks because of their new mission.

Following Congress’ 2021 approval of the Air Force’s plan to retire its Block 20 and 30 Global Hawks, the program arranged to receive those aircraft as well. Last October, TRMC accepted four Block 20 Global Hawks from the Air Force and expects to complete the transfer of 20 Block 30 systems by the end of this month.

Northrop Grumman, which built the Global Hawk, will perform the conversions and TRMC is in the process of negotiating how many aircraft will be delivered in the first batch. The plan is for the initial Range Hawks to be ready to support testing in 2024.

It takes at least several months to retrofit a single aircraft, Rumford said, starting with a full system overhaul to ensure the system is up to date on maintenance. The conversion itself is largely focused on readying the RQ-4 to perform a new mission in which it looks up at the targets it is tracking rather than down, as it was originally designed. This involves repositioning onboard avionics and installing new sensors and instrumentation suites that can track a hypersonic vehicle flying overhead. Rumford noted that TRMC has a separate contract with instrumentation providers to perform those installations.

Beyond the initial Block 20 and 30 Global Hawks, the program is tracking the Air Force’s plans to retire its Block 40 RQ-4s in 2027, which could present an opportunity to grow the Range Hawk fleet by nine aircraft. Rumford said TRMC is also looking to take in some retired MQ-9 Reapers, which can carry instrumented pods to provide telemetry and flight safety support. The team is working with General Atomics, the MQ-9 manufacturer, to explore the optimal ways to outfit the Reaper for SkyRange.

Can satellites be used for hypersonic testing?

The program is also in the early phases of studying how satellites could be used to support hypersonic testing, Rumford said. Over the next few years, TRMC and the office of the principal director for hypersonics will work with the Space Development Agency, the Space Force and the Army to prototype the concept, exploring how to better leverage space assets for the SkyRange mission.

“That will be a game changer,” Rumford said. “We’ll see what the study shows, but the real question is how many systems are we going to have to be able to support testing and what’s the density going to be?”

Another question is whether the program would have its own dedicated satellite constellation or be dependent on an existing fleet. The answer will need to balance availability concerns with the cost of a standalone system, he said.

Rumford said he expects the team to develop a strategy for satellite support by 2025, with several experiments and prototyping efforts planned between now and then.

“Sometimes when people think study, they just think it’s all a paper exercise,” he said. “But I’ve tasked them to demonstrate that actual hardware can be developed and engineered and proven to help inform this decision.”

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