Racing to prototype and field an operational hypersonic missile, the Air Force skipped some typical testing steps—and now should go back and address them, the Director of Operational Test and Evaluation said in his annual report to Congress.
The Air Force’s AGM-183A Air-launched Rapid Response Weapon (ARRW) flew a successful full-up test in December. But DOT&E concluded in its report that ARRW is:
- Flying operational tests without an approved test plan;
- Potentially vulnerable to cyber disruption;
- At risk of insufficient test range availability; and
- Lacking in modeling and simulation capability to properly evaluate the weapon;
- Behind in warhead testing.
“Despite being under DOT&E oversight for over four years, the AGM-183A Air-Launched Rapid Response Weapon (ARRW) Program Office does not have a DOT&E-approved Integrated Master Test Plan nor has the Office submitted an Operational Demonstration Plan,” notes the report, signed by DOT&E chief Nickolas H. Guertin. The Air Force is developing an integrated master plan for test, he said, which DOT&E has to approve.
ARRW is a Section 804 Rapid Prototyping, Mid-Tier Acquisition program, which leverages “lessons learned from the Defense Advanced Research Projects Agency’s Tactical Boost Glide vehicle program,” the DOT&E said. Launched on an accelerated schedule because China is ahead on hypersonic technology, the weapon is being developed by Lockheed Martin.
Little has been divulged about the effort. According to DOT&E, ARRW is a “conventional, air-launched, boost-glide, hypersonic weapon consisting of a solid rocket motor booster, a glider protective shroud, and a glider vehicle containing a kinetic-energy projectile warhead.”
Launched from B-52H aircraft, ARRW aims to provide standoff capability “to destroy fixed, high-value, time-sensitive, land-based targets in anti-access/area-denial environments,” DOT&E said. But ARRW “has not yet demonstrated the required warfighting capability,” the report continued, and while the weapon is designed to swiftly destroy targets in highly-defended areas, it has not undergone formal cyber testing, and the Air Force’s ability to simulate its performance is challenged by a lack of digital models.
To get the program back on track from its perspective, DOT&E offered three recommendations:
- Deliver an adjudicated Integrated Master Test Plan and Operational Demonstration Plan for DOT&E approval;
- Verify, validate, and accredit modeling and simulation tools to simulate and assess ARRW performance;
- Assess ARRW’s survivability in a cyber-contested environment.
The 412-page DOT&E report, released this month, details the testing status of major systems under development by the military services.
The ARRW has completed three successful tests “demonstrating proper function of the solid rocket motor, shroud separation,” and glider separation.
The next phase of testing began in December, with the first “all-up” test, which was deemed a success. Three more rounds with live warheads will follow in 2023.
All ARRW tests with all-up rounds “involve land impacts,” Guertin said. “The Air Force currently is producing a limited number of ARRWs, with four all-up rounds intended for test and evaluation. But DOT&E said that is not sufficient. The limited number of planned test assets and test targets will not allow an assessment of operational effectiveness, including lethality, suitability, and survivability, the report said.
The Air Force has said it will have leftover weapons that can be operationally employed once testing is complete. The last budget funded construction of 12 ARRWs, but the program also requires Lockheed to demonstrate an ability to rapidly produce more if required.
Air Force Secretary Frank Kendall expressed dissatisfaction with ARRW’s progress prior to the successful tests in late 2022. DOT&E noted “hardware and software problems have delayed planned ARRW operational demonstration flights … precluding an initial assessment of risks to demonstrating the ARRW’s intended operational effectiveness.”
One attempted launch failed because “a low voltage caused a built-in-test fault upon application of power, causing the weapon to prevent launch.” Software fixes were put in place by the Air Force, allowing success on subsequent tries.
“The program also completed the last of six warhead characterization arena tests in early FY22,” the DOT&E revealed.
Industry officials said the ARRW doesn’t rely simply on the kinetic force of striking a target with high velocity but uses a warhead.
“Lethality testing is ongoing, precluding an initial assessment of ARRW warhead performance,” Guertin said. “Given the limited number of planned test events, there is risk to demonstrating the ARRW lethal effects against the required tactical and strategic targets.”
Industry officials said the warheads to be employed by hypersonic weapons can be well protected from the extreme heat at the leading edge of the missile, and Lockheed is working on electronics that can function well at high temperatures. That in turn could allow lighter-weight structures in turn permitting larger warheads or longer range.
“The Air Force plans to use engagement-level and mission-level modeling and simulation to assess ARRW survivability against surface-to-air missile systems and anti-aircraft artillery batteries,” DOT&E said, but noted that those M&S tools are not yet mature. The survivability of ARRW has not been assessed, although it high speed is expected to confer a degree of survivability.
The report said it’s not clear if a single ARRRW could get through early warning systems, surface-to-air missile systems, and anti-aircraft-artillery batteries. “The final survivability assessment should also estimate such probabilities in the presence of multiple threat systems connected by threat-representative integrated air-defense systems capable of detecting, tracking, and engaging multiple airborne targets, including hypersonic weapons like the ARRW,” DOT&E said.
Cyber threats could also pose a risk. “An assessment of ARRW’s survivability within a cyber-contested environment is not currently scheduled, but should be completed before [an] acquisition production decision,” Guertin said. “The Air Force plans to execute an operational demonstration to assess the operational capabilities and limitations of the system, yet DOT&E has yet to see a completed Operational Demonstration Plan.”
DOT&E also signaled concern about the lack of test ranges for ARRW and other hypersonic weapons. “The program flight test schedule could be delayed due to the limited number and availability of hypersonic flight corridors, target areas, and test support assets,” Guertin said. “The program will be competing for these limited resources with other hypersonic programs, including those being developed by the Navy, Army, and Missile Defense Agency.”
The Pentagon and the Air Force have both said they plan to invest in ways to make better use of limited range space, such as using Global Hawk aircraft for data collection and telemetry, and investing in more wind tunnels and ground test capabilities.