High-Altitude Sensing Quest Nears U.S. Army Launch

Global 6000 aircraft

An L3Harris-owned Global 6000 is helping the U.S. Army learn the capabilities of a high-altitude surveillance system.

Credit: U.S. Army

Sweeping change is coming to the U.S. Army’s fleet of fixed-wing intelligence-gathering aircraft over the next several years. A new fleet of jets, stratospheric balloons and advanced sensors is entering the acquisition process as the service transforms targeting systems for long-range weapons aimed at adversaries.

  • HADES payload development enters Phase 2
  • U.S. Army outlines plans for Hermes, ARGOS and Helios

The Multi-Domain Sensing System (MDSS) is transitioning a new jet-powered surveillance capability from prototyping to the development stage over the next year, pushing the sensing reach of the Army’s fixed-wing aviation fleet hundreds of miles downrange. A potential acquisition of stratospheric balloons and possibly fixed-wing uncrewed aircraft systems (UAS), could expand the Army’s sensor horizon by thousands of miles.

“To ensure that Army forces will be able to see more, farther and more persistently than our enemies, we are modernizing our aerial ISR [intelligence, surveillance and reconnaissance] capabilities,” Army Secretary Christine Wormuth said at the Army’s Maneuver Warfighter Conference at Fort Benning, Georgia, on Sept. 13.

The Beechcraft King Air-derived RC-12X Guardrail Common Sensor fleet has been performing the Army’s long-range targeting mission for decades, but the medium-altitude, turboprop-powered fleet is scheduled to be retired or transferred to a different mission by the end of 2025.

By then or shortly after, that fleet could be replaced by one of contractor-owned or -operated Bombardier Global 6500-derived jets. Each aircraft would be equipped with the High-Accuracy Detection and Exploitation System (HADES), a multi-intelligence payload that can find targets by eavesdropping on electronic and communications signals, then identify them in any weather with a synthetic aperture radar and track them with a ground moving-target indication mode.

“The Multi-Domain Sensing System comprised of the HADES manned platform as well as unmanned elements will provide more sensing for joint targeting at the theater level,” Wormuth said. “An expanded family of UAS will do the same at the division, brigade and battalion level.”

By operating at above 40,000 ft., the range of the future, HADES-equipped airborne fleet will match an expanding portfolio of long-range precision missiles with the ability to strike targets 1,700 mi. away, Wormuth said. The latter figure aligns with the range of the hypersonic glide vehicle-equipped Lockheed Martin/Dynetics Dark Eagle missile, which is scheduled to be fielded in 2023 by the Long-Range Hypersonic Weapon (LRHW) program.

The  ground-launched missile in the current arsenal with the longest range is the MGM-140 Army Tactical Missile System (Atacms), which is launched by the High-Mobility Artillery Rocket System  and has a range of 300 km (186 mi.). A Guardrail sensor on an RC-12X can support the Atacms range, but not that of the LRHW or other new long-range missiles entering the Army’s inventory within the next two years.

By 2024, the service plans to field the first elements of a long-range strike makeover of the ground force’s traditionally short-range artillery systems. In addition to the LRHW, the Raytheon SM-6 ballistic missile and BGM-109 Tomahawk cruise missile will be fielded with ground launchers under the Mid-Range Capability (MRC) program in fiscal 2023.

A future version of the MRC is expected to include a 1,000-km-range version of the Lockheed Precision Strike Missile (PRSM). The rocket-boosted PRSM is scheduled to enter service next year with a range of about 500 km. The Army’s latest budget documents, however, revealed plans to field a new version of the PRSM with a combined-cycle, rocket-boosted, air-breathing propulsion system, which should more than double the range of the baseline version.

The pending retirement of the RC-12X Guardrail Common Sensor fleet offers the Army an opportunity to move from medium- to high-altitude airborne surveillance. Credit: U.S. Army

Each of the new systems will be fielded with the service’s newly created Multi-Domain Task Forces (MDTF).

“We’ve deployed our MDTFs forward in Europe and in the Indo-Pacific, and we have a plan to do the same with the new Mid-Range Capability and the Long-Range Hypersonic Weapon batteries in [fiscal] 2023,” Wormuth said.

On Sept. 13, the Army awarded contracts worth a combined $18 million to L3Harris and Raytheon to begin Phase 2 of the HADES competition. In Phase 1, both companies designed their payloads to meet electronic and communications intelligence  requirements. The Army also wants to integrate a synthetic aperture radar with a ground moving-target indication mode.

Now the two competitors will adapt their designs to work on a business jet platform such as the Global 6500. The HADES payload is scheduled to be ready for fielding by 2026, a timeline that suggests procurement of the first aircraft will begin in fiscal 2024.

“The goal is to provide deep-sensing intelligence collection of indicators and warnings, electronic order of battle and patterns of life for target development,” Dennis Teefy, Army project director for sensors-aerial intelligence (PD-SAI), said in a Sept. 13 news release. As that office manages the HADES program to develop the payload, the Army’s Fixed Wing program office is preparing to acquire the aircraft. The combined acquisition approach appears carefully designed to avoid the technological stumbles that doomed the Aerial Common Sensor program nearly 15 years ago. That program attempted to field the Army’s first high-altitude surveillance aircraft, but the Defense Department canceled the Lockheed Martin program in 2006 after the multi-intelligence sensor payload outgrew the capacity of the Embraer ERJ-145 regional jet.

But the MDSS HADES fleet will enter service in 2026, after at least five years of experiments, demonstrations and deployments with Army-funded surveillance jets. In July 2020, Leidos deployed the Airborne Reconnaissance Targeting and Exploitation Multi-Mission Intelligence System (Artemis), a company-owned Bombardier Challenger 650 business jet equipped with the Sierra Nevada Corp.’s SS-4000 signals intelligence payload. The latter is currently the intelligence system aboard the RC-12X fleet. Last April, L3Harris deployed a company-owned Bombardier Global 6000 as the Airborne Reconnaissance and Electronic Warfare System (ARES), part of the next phase of the Army’s demonstration program.

In the Artemis and the ARES aircraft, the service has the rare opportunity to experiment with a new class of intelligence-gathering aircraft years ahead of buying their own. Although intended as experimental systems, the contractor-owned and -operated aircraft have been used in real-world missions, with the Artemis used extensively last November in Eastern Europe for surveillance of Russia’s preinvasion buildup around Ukraine and the ARES, sent four months later to the Western Pacific Ocean to monitor missile launches by China.

Airbus Zephyr
The 64-day, continuous flight by the Airbus Zephyr ended in a crash, but the mission showed the Army how to develop and use stratospheric uncrewed aircraft systems or balloons to dramatically expand the surveillance horizon. Credit: U.S. Army

The Army’s decision to acquire business jet-class aircraft for aerial ground surveillance has prompted some skeptical inquiries. The U.S. Air Force is in the process of divesting the Northrop Grumman E-8C Joint Stars fleet. A plan to buy a business jet-class replacement for the E-8C was canceled in 2019 because of concerns that such an aircraft had become too vulnerable. Indeed, Congress passed the fiscal 2022 authorization bill for the Defense Department last year with an amendment requiring the chairman of the Joint Chiefs of Staff to personally certify that a HADES-equipped aircraft could perform its mission “at standoff distances sufficient to survive against enemy air defenses.”

But Army officials have defended the decision to use sensor-laden business jets. The service concedes that such aircraft are vulnerable near the front lines after a war begins. However, it thinks the fleet is still needed in the prehostilities phase, with the ability to contribute to the electronic order of battle and establish a baseline for the positions of fixed and mobile targets. Leidos’ Artemis aircraft appeared to perform such a role near Ukraine in the three-month buildup before Russia invaded Ukraine on Feb. 24.

Business jets are not the only high-altitude platforms on the shopping list. Teefy is evaluating multiple types of new platforms to dwell in the airspace between 70,000-100,000 ft., which has been reserved for aircraft such as the Lockheed Martin U-2S and, formerly, the Lockheed SR-71A. The technologies under review include a new version of the Northrop Grumman RQ-4 Global Hawk UAS, which could operate at up to 70,000 ft., about 7,000 ft. higher than the current version.

The Army also is evaluating a new generation of high-altitude balloons, which could search for targets deep behind enemy lines at altitudes up to 100,000 ft., as well as dispense swarms of small unattended ground sensors or small UAS. Finally, it also is considering solar-powered aircraft that could loiter at the top of the stratosphere for weeks or months, as shown by the recent 64-day flight demonstration by the Airbus Zephyr. The Zephyr crashed on Aug. 18, ending its record-breaking endurance flight, but not before the UAS demonstrated its ability to serve as a communications relay and intelligence collector. Further flight demonstrations have been postponed until fiscal 2023 pending a crash investigation.

The new high-altitude platform concept entered the Army’s process for considering new acquisition programs earlier this year. An approval later this year or next year could pave the way for developing a proof-of-concept for the High-Altitude Extended-Range Long-Endurance Intelligence Observation System (Helios), which may involve a high-altitude UAS or balloon or multiple systems. Each may carry two potential future payloads: the High-Efficiency RF Monitoring Exploitation System (Hermes), and the Aerial Geoint System (ARGOS).

“Hermes is the emerging requirement for a future MDO [Multi-Domain Operations]-capable signals intelligence sensor, and ARGOS for [an] MDO-capable geospatial intelligence sensor,” Maj. Gen. Anthony Hale, commander of the Army’s Intelligence Center of Excellence, wrote in an internal newsletter released during the second quarter of fiscal 2022. “Helios will operate at [60,000-100,000 ft.] and provide capabilities that close the deep-sensing gap for MDO. The campaign of learning for Helios concepts will involve preprototypes with planned participation in experiments and demonstrations.”

If fielded successfully, this overall MDSS could sweep the battlefield for targets at altitudes of 30,000-100,000 ft. Below 30,000 ft., a new family of advanced UAS also may be developed. The Army’s original vision for the Future Vertical Lift family of systems included an Advanced UAS (AUAS) concept to replace the General Atomics Aeronautical Systems Inc. MQ-1C Gray Eagle. That acquisition program was deferred to the mid-2030s, allowing acquisition officials to concentrate on fielding the Future Long-Range Assault Aircraft and the Future Attack Reconnaissance Aircraft.

Steve Trimble

Steve covers military aviation, missiles and space for the Aviation Week Network, based in Washington DC.