Common Aero Vehicle (CAV)
The Common Aero Vehicle (CAV) program was initially slated for a flight demonstration in FY2003. CAV would provide both an expendable and future reusable Military Space Plane [MSP] system architecture with the ability to deploy multiple payload types from and through space to a terrestrial target. A CAV will be able to achieve high terminal accuracy, extended cross range and be highly maneuverable in a low cost expendable or single use package supporting multiple military mission areas.
In early 1996, a meeting was held at TRW's Colorado Springs, Colorado facility to name this new weapon and lay out a plan for its eventual design, test, acquisition, and employment. The basic concept was for a maneuvering reentry vehicle using common guidance, navigation, and control (GN&C) as well as a common aerothermodynamic shell, to deliver a wide variety of submunitions, unitary penetrators, or intelligence, surveillance, and reconnaissance (ISR) platforms or sensors.
Since the concept used a common aero shell, the decision was made to call the new weapon the Common Aero Vehicle or CAV. The same CAV would also be common to a large number of launch systems, including RLVs, expendable launch vehicles (ELVs), retired Inter-Continental Ballistic Missiles (ICBMs), and air launch from a variety of platforms. The "Aero" term was short for "aerothermodynamic shell" and not for "aerospace", as mistakenly used in some documents. Early briefings by prime contractors even used the title "Common Aeroshell Vehicle" before they began using the shortened Common Aero Vehicle name.
Early work with Sandia National Laboratories had resulted in Phillips Lab's MSP Technology Office showing graphics of a very simple, flap controlled, biconic hypersonic weapon. Meetings with TRW, Boeing, Lockheed-Martin, Wright Lab's Munitions Directorate and Phillips Lab's Ballistic Missile Technology Office showed a large body of research existed on much more sophisticated maneuvering reentry vehicles which could be adapted to the CAV concept. Boeing had the most actual flight test experience with programs such as Boost Glide Reentry Vehicle, Maneuvering Control and Ablation Studies (MARCAS), Advanced Control Experiment (ACE), Advanced Maneuvering Reentry Vehicle (AMaRV), and Technology Demonstration Maneuvering Reentry Vehicle (TDMaRV). All of these programs had direct applicability to CAV, especially AMaRV.
AMaRV flew several times in the late 1970s and early 1980s and demonstrated profiles similar to those a CAV would fly. Lockheed-Martin had two programs, MSTART and High Performance Maneuvering Reentry Vehicle (HPMARV) which were directly related to CAV. HPMARV, in particular, had detailed computational fluid dynamics (CFD) and wind tunnel analyses, even though the vehicle never flew. Boeing and Lockheed-Martin were both provided small amounts of funding over the next few years to mature their CAV designs and recommend employment, test and acquisition options.
Two (of three attempts) successful Missile Technology Demonstration (MTD) tests were made using a modified Pershing reentry vehicle (RV) to deliver Eglin AFB-designed unitary penetrators in White Sands Missile Range. MTD-1 penetrated 31 feet into 2500 pounds per square inch (psi) weathered granite after impacting at over 3000 feet per second (fps). For reference, hardened concrete measures 5000 psi. MTD-1's INS/GPS navigation system performed flawlessly. MTD-2 had a launch vehicle malfunction resulting in launch vehicle destruction. The larger MTD-2 unitary penetrator was so tough, however, it was recovered and used successfully on MTD-3.
Using Young's equation and ignoring some penetrator physics limits, penetration depths of 40-60 feet into 5000 psi hardened concrete can be calculated using an 800-1000 lb penetrator at 4000-4500 feet per second impact velocity.
An overarching goal of CAV is to be cost competitive with cruise missiles and other precision guided munitions (PGMs). The BGM-108 Tomahawk Land Attack Missile (TLAM) and AGM-86C Conventional Air Launched Cruise Missile (CALCM) have been priced in various sources at $0.8-2.5M each. CAV's original goal was cost competitiveness with the AGM-158A Joint Air to Surface Standoff Missile (JASSM). JASSM, however, came in at less than $400K, a price CAV cannot match. Best estimate of CAV costs from the prime contractors is ~$1.5M per CAV.
CAV has a relatively high hypersonic lift to drag ratio (L/D) to give good cross-range. CAV cross-range is roughly 1000 times the hypersonic L/D and typical CAV hypersonic L/Ds of 2.0-3.0 thus give 2000-3000 nautical miles of cross-range. CAV needs to be deployed at very high velocities to be effective and Mach numbers less than 20 for suborbital deliveries produce relatively short ranges and cross-ranges.
DARPA's FALCON (Force Application and Launch from CONUS) program was intended to produce a CAV capable of providing a reasonable penetrator capability from an expendable launch vehicle or retired ICBM in the 2008 timeframe.
Using a once around launch where the SOV does not go all the way to orbit can increase payload from 20-60%, depending on SOV configuration, compared to direct orbital insertion. This translates into more CAVs available for tasking for the same amount of available lift. Also, the higher a CAV must be placed in orbit, the more propellant required for the upper stage or bus to reach that orbit.
FALCON had no funding for any on-orbit CAV effort.
|Join the GlobalSecurity.org mailing list|