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The Air Force and Defense Advanced Research Projects Agency (DARPA) are teaming up on a project to develop the means to deliver conventional munitions anywhere in the world from the continental United States (CONUS) on short notice.
The Force Application and Launch from CONUS (FALCON) program reflects a mission needs statement (MNS) for prompt global strike capability approved by the defense Joint Requirements Oversight Council (JROC) in 2003. The JROC also approved another MNS for operationally responsive spacelift to orbit small satellites on short notice. The three-phase effort will demonstrate both rapid launch and hypersonic flight. The results may provide a near-term operational capability with a small launch vehicle (SLV) and an expendable common aero vehicle (CAV) around 2010. A far-term capability around 2025 introduces a powered, reusable hypersonic cruise vehicle (HCV) able to strike any point on earth in less than two hours.
Ballistic missiles have long provided global strike capability with nuclear warheads, but precision strike around the world with conventional munitions is still the job of manned bombers. Though B-2s flew non-stop from Missouri to Afghanistan and back in 2001, CONUS-launched missions take nearly a day to reach their targets. In contrast, tactical ballistic missile threats need just two to four hours to deploy and prepare for launch. Even bombers based in the United States generally require forward-deployed aerial tankers and overflight permission from foreign governments.
To bypass the limitations of bombers, FALCON envisions an expendable CAV that rides an SLV from a CONUS launch to hypersonic speeds, and then maneuvers without power to deliver one or more munitions accurately. As the deputy program manager, Lieutenant Colonel Steven Einstman, explained it, “We’re in the businesses of trying to respond where we don’t have assets in place. We’re trying to beat the timelines of what we have now.”
Unlike a ballistic missile, a gliding CAV could take en route targeting updates or wave-off orders based on the latest intelligence. Maneuvering could also steer the vehicle around terminal defenses. “What the CAV does is give the warfighter additional flexibility versus a ballistic missile,” Einstman said.
Impact velocities around 4,000 feet per second maximize the power of a ground-penetrating munition. Alternatively, the unmanned CAV could release multiple small-diameter bombs or wide-area munitions like those typically delivered by tactical aircraft based in the combat theater. The Falcon program evolves the CAV to an enhanced CAV (ECAV) with greater range and maneuverability, and provides technology for a still-unmanned HCV able to operate from conventional runways.
Shortening the global strike timeline first requires an “operationally responsive” spacelifter compatible with both the CAV and small satellites. Each FALCON phase therefore pursues SLV technologies in Task I and CAV technologies in Task II. DARPA will choose Phase II SLV contractors from an open solicitation.
Phase II, Task II of the FALCON program will emerge from a limited competition among the Phase I CAV contractors. Funding is split evenly between DARPA and the Air Force for the life of the program, with DARPA providing the program manager and the Air Force the deputy program manager. Integrated product teams have been set up at Space Command and Air Force Research Lab sites.
The six-month FALCON Phase I concept definition effort began with contract awards in November 2003. Nine SLV and four CAV contractors are to deliver trade studies and launch concepts supported by risk mitigation, technology maturation and demonstration plans.
The 36-month Phase II launches detailed design with two SLV and two CAV contractors, and it provides SLV and CAV flight hardware. It also starts design work on the ECAV and HCV. Phase II demonstration plans will be based on proposals from Phase I contractors, but to reduce overall program risk, the notional program calls for the SLV to launch a dummy payload initially and for the CAV to fly first on an existing booster.
The SLV and CAV will fly together in the 30 months of FALCON Phase III, with the flight demonstrations being with full-scale prototypes. Phase III test should include the first flight of an ECAV and demonstrations of large HCV components for a FALCON technology base.
“They will have demonstrated the real capability Space Command is looking for, and proved out capabilities and technologies that leave a blueprint for an operational system,” Einstman said.
The FALCON near-term capability calls for a 2,000-pound CAV to fly 3,000 miles from its SLV launch insertion point. The CAV size is determined by its 1,000-pound unitary penetrator payload. While the CAV should be able to hit targets up to 800 nautical miles off a straight trajectory, the ECAV will be able to maneuver up to 3,000 miles off a predictable path. The far-term hypersonic cruise vehicle would carry 12,000 pounds up to 9,000 miles, which is far enough to reach any point on earth from launch sites on the U.S. Atlantic and Pacific coasts. The reusable far-term vehicle may also provide the launcher for a two-stage-to-orbit spacelifter.
Launch On Demand
The Air Force Space Command, Air Force Research Laboratory and NASA are near concluding their analysis of alternatives for operationally responsive spacelift. Their findings will tie into FALCON SLV objectives. “We’re going from a launch-on-schedule culture to a launch-on-demand culture for certain missions,” Einstman said. Although complicated satellites and kinetic energy munitions have different pre-launch requirements, he added, “The objective for us is to get down to days and hours as opposed to weeks and months.”
The FALCON program awarded Phase I, Task I contracts to AirLaunch, Andrews Space, Exquadrum, KT Engineering, Lockheed Martin Space Systems, Microcosm, Orbital Sciences Corp. (OSC), Schafer and Space Exploration Technologies. The contractors have been asked for concepts that will place a 1,000-pound payload in a 100 mile low Earth orbit launched due east.
“We’ve given them a challenge of essentially being able to launch within 24 to 48 hours,” said Einstman.
A potentially more difficult standard involves the Air Force decision to cap the cost per launch at $5 million, excluding payload preparation and integration. Lockheed Martin Michoud estimates that current launch vehicles cost anywhere from $18 million to $32 million to accomplish the same mission.
While details of their concepts are competitive secrets, the SLV contractors approach the FALCON objectives with a range of solid, liquid and hybrid propulsion vehicles. OSC, for example, notes that its solid-propellant Pegasus and Taurus and hybrid Minotaur launch vehicles already carry SLV-class payloads. “The part that’s new with FALCON is not more pounds to orbit, but the quick reaction and dramatically lower cost,” says Robert Richards, OSC vice president of orbital launch systems. “That second requirement is the real challenge.”
OSC is studying a modular launch system with both air- and ground-launched vehicles to provide affordable spacelift and global strike capability. Air launch affords added flexibility for hypersonic weapons trajectories, while ground launch is more compatible with spacelift to common satellite trajectories.
Modular elements for both launch scenarios are part of the strategy for achieving an affordable solution. “We don’t think that technology alone is the enabling feature,” Richards said. “Really, manufacturing rate and launch rate are the critical elements.”
AirLaunch, which was established specifically in response to the FALCON request for proposals, is basing its FALCON effort on an air-launched SLV dropped from an unmodified cargo aircraft. “FALCON is a challenging program from the standpoint of both cost and responsiveness, but in our view technology is somewhat less important to the successful realization of the concept than finding management methods to reduce costs that are imposed on the launch of a rocket,” said program manager Gary Hudson.
Exquadrum won a FALCON Phase I SLV contract in collaboration with Environmental Aeroscience Corp. (eAc) and Cesaroni Aerospace. eAc specializes in nitrous oxide/liquid oxygen hybrid rocket motors and has significant flight experience with hybrid propulsion sounding rockets, while Cesaroni Aerospace provides expertise in erosion-resistant rocket nozzles.
Exquadrum president Kevin Mahaffy acknowledged the difficulty of developing the low-cost launch technology needed by FALCON. “In effect, DARPA and the Air Force are asking for a five-fold reduction in price in comparison to the most comparable, operational system. We have to do things very differently in order to get a different result from traditional, high-cost systems.”
Fast Mover
While FALCON SLV technologies may not require technical breakthroughs, the one-shot CAV and reusable HCV to be developed under FALCON Phase 1, Task 2 will demand advances in high temperature materials, thermal protection systems and boundary layer transition management. Hypersonic speeds with a maneuvering vehicle also call for new guidance, navigation and control technologies, and the ability to communicate through plasma.
Andrews Space, Boeing, Lockheed Martin and Northrop Grumman received FALCON Phase 1, Task 2 contracts.
Andrews Space and Lockheed Martin are the only FALCON contractors participating in both SLV and CAV concept studies. “We have a unique opportunity to look at the integrated problem,” says Livingston Holder, Andrews Space vice president for space systems. The company proposes a rocket plane to carry the unpowered CAV to insertion speed and altitude.
“The challenge is, once you release this thing, how does it go the rest of the way?” Holder noted. Unlike returning space shuttles or ballistic re-entry vehicles, the FALCON CAV and HCV will sustain speeds around 20,000 feet per second or greater for many minutes. “Most things going that fast in the atmosphere are on their way in from orbit and slowing down.”
A hypersonic glide bomb in a flat trajectory can easily overshoot the entire combat theater, so even an unmanned CAV still demands extraordinary precision and reliability. However, a 2,000-pound CAV with a 1,000-pound munition has little space for flight control and thermal management systems. “That 1,000 pound package is a pretty smart package,” said Holder. “It has to find its way to the target, shed heat through the atmosphere and communicate back to a control center.”
To answer the combined challenges, Andrews Space has assembled an industry team including Raytheon Missile Systems and the hypersonic experts at Alliant Tech Systems.
Northrop Grumman’s Integrated Systems sector built a FALCON Phase 1, Task 2 team that includes the Northrop Grumman Mission Systems and Electronic Systems sectors and subcontractors Aerojet-General, Space Works, Textron Systems, HITCO Carbon Composites and Pratt & Whitney.
Even with their different operating profiles, the FALCON CAV, ECAV and HCV all pose a common problem, according to Northrop Grumman officials. “The thermal protection system itself is the most difficult aspect of this whole project,” observed FALCON program manager Dennis Poulos.
The space shuttle thermal protection system is designed to dissipate heat as the vehicle slows down quickly. “The purpose of the CAV and ECAV is to glide quite a while, so we’re probably going to have a longer exposure to high temperatures than we have with the Shuttle,” said Poulos.
Thermal protection systems only delay heat build-up, and hypersonic heating problems are more than skin-deep. “You still have to manage the heat that gets inside the vehicle,” Poulos pointed out.
With greater maneuvering capability, the ECAV will fly longer than the basic CAV and have to manage even tougher thermal loads. The reusable HCV poses additional challenges. All three vehicles will need to communicate in a plasma environment, so antennas must double as parts of the thermal protection system.
With a successful test program, FALCON lays the foundation for a HCV able to take off and land on conventional runways.
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