FAS | Space Policy | Star Wars | Programs |||| Index | Search | Join FAS

Joint Land Attack Cruise Missile Defense Elevated Netted Sensor [JLENS]

The Joint Land-Attack Cruise Missile Defense Elevated Netted Sensor System (JLENS) consists of an aerostat with radars to provide over-the-horizon surveillance for defense against cruise missiles. JLENS is primarily intended to tackle the growing threat of cruise missiles to US forces deployed abroad. The system enhances cruise missile detection and engagement ranges with current air defense weapons such as PATRIOT, Navy SM-2 missile, the Advanced Medium Range Air-to-Air Missile, and ultimately the Medium Extended Air Defense System and the Corps Surface-to-Air Missile System.

JLENS will operate at altitudes between 10,000 and 15,000 feet; be capable of detecting long range, terrain masked targets; and provide an effective fire control solution for joint theater air and missile defense weapon systems. Additionally, it can operate from sites on both land or sea, and is tactically relocatable. Comparing these capabilities against the performance of our current sensor systems, the value added of JLENS is readily apparent.

JLENS is a large, unpowered elevated sensor moored to the ground by a long cable. From its position above the battlefield, the elevated sensors will allow incoming cruise missiles to be detected, tracked, and engaged by surface-based air defense systems even before the targets can be seen by the systems. The elevated sensors have several characteristics, which may make them especially suited to CMD. They are less expensive to buy and operate than comparable fixed-wing aircraft. This makes them the most affordable alternative for achieving a near-term CMD. The elevated sensors can stay aloft up to 30 days at a time providing 24-hour per day coverage over extended areas.

The internal pressure of JLENS is about the same as the exterior pressure. This makes them extremely difficult to shoot down. These elevated sensors can absorb lots of punctures before they lose altitude. When they do, they come down so slowly that they can be reeled in, repaired easily, and sent right back up. In the long term, JLENS would complement fixed-wing aircraft performing a similar mission, and this will provide the U.S. more robust and flexible CMDs. Mooring systems for large JLENSs covering major portions of a theater of operations would probably be relatively permanent. For short or medium range surveillance and fire control, JLENSs would be smaller and the mooring systems could be transportable or ground-mobile.

In January 1996, the Army was directed by the Department of Defense and the Joint Chiefs of Staff to take the lead in establishing an Aerostat Joint Project Office (Army, Navy, and Air Force). The (then) U.S. Army Space and Strategic Defense Command was formally tasked to stand up the Aerostat Joint Project Office in Huntsville, Ala. The Navy and the Air Force were directed to provide full-time deputy program managers and share in providing other services support to the program. The JLENS Project Office initiated concept studies and related risk reduction efforts following approval of the JLENS acquisition strategy. The concept studies phase of the program was completed on Aug. 1, 1997. A request for proposal for one JLENS sensors demonstration system was released in late June 1997.

On 30 January 1998 the US Army Space and Missile Defense Command (SMDC) awarded a big contract for the JLENS system to Raytheon Company in Huntsville, AL. The JLENS demonstration program has three primary objectives: mitigation of the risk associated with the execution of the program; design, development, procurement, fabrication, integration, test, demonstration, and maintenance of a system which meets the performance specification; and development of an operational "leave behind" system for user evaluation and for use in the event of a contingency deployment. Total program value, including options for system development/demonstration and operation and sustainment is approximately $300 million. Raytheon's efforts on the JLENS program will be conducted in Raytheon facilities in Massachusetts, California, Florida, and Virginia. Major subcontractors are TRW, TCOM, L.P., Mercury Computer, and Hewlett Packard.

Using an aerostat provided by the Air Force, the JLENS Project Office participated in the 1996 Roving Sands Demonstration and provided an over-the-horizon air picture to interested participants for the duration of the exercise. A connection to the Multi-Link Translator and Display System local area network allowed JLENS to inject tactical data information link-J messages into the Joint Tactical Information Distribution System, or JTIDS, network. JLENS transmitted the full air picture, including a number of targets that had not been reported before because the surface-based sensors did not have the capability to send track messages over a JTIDS network to Patriot, THAAD, AEGIS and SHORAD. A German Patriot unit reported killing a cruise missile with JLENS' track number, demonstrating cueing by the JLENS. The exercise also allowed the JPO to identify and evaluate battle management/command, control, and intelligence interface requirements; provide training and hands-on experience for JLENS launch, recovery, and ground station operations; and establish a test bed for follow-on testing and program risk reduction efforts. The Roving Sands Exercise demonstrated that from its highest altitude of 15,000 feet above ground level, the JLENS sensor can locate and track targets, providing the battlefield commander with early warning of air and ground threats previously hidden from view.

JLENS proved its operational utility in the joint arena in the All Service Combat Identification and Evaluation Team '99, or ASCIET '99, exercise. A 15 m aerostat was deployed with a Cooperative Engagement Capability, or CEC, relay on a mobile mooring station. This relay allowed the Army's Patriot air defense system and the Navy's Aegis weapon system to exchange radar data, share a Single Integrated Air Picture, or SIAP, and conduct simulated engagements for the first time in an operational environment. JLENS also demonstrated at ASCIET the high operational availability potential for elevated CEC and JTIDS relays, and the JLENS Prototype Processing Station's capability to process, correlate and display a SIAP from multiple sensor sources.

In mid-1999 the JLENS team participating in the US Army's Roving Sands Exercise is conducted tests aimed at extending the system's flight time in poor weather. Roving Sands '99 will showed JLENS current capability as a blue force player, participating under the sponsorship of the US Army's 32d Air and Missile Defense Command. Building on ASCIET successes, JLENS merged air tracks from multiple elevated aerostat based radars with tracks obtained from JTIDS and Tactical Information Broadcast Service. JLENS air tracks were reported to exercise players over JTIDS. JLENS relay work from ASCIET was expanded to include the Single Channel Ground and Airborne Radio System and the Enhanced Position Location Reporting System to support the overall exercise. During the Advanced Concept Technology Demonstration portion of Roving Sands, the JLENS objective capability was demonstrated using simulated surveillance track data processed and transmitted over the JTIDS network to the other blue force players.

The aerostat used by the JLENS Project Office in the exercise at White Sands Missile Range, N.M., is 233 feet long; is filled with 590,000 cubic feet of non-explosive, non-flammable helium; and has a hull volume two and a half times the volume of the largest advertising blimps flying today. Aerostats differ from blimps in that blimps are powered while aerostats are tethered or anchored to the ground. The tether also supplies electrical power to the aerostat.

JLENS was designated an Acquisition Category II program in March 1999. Long term acquisition requirements call for 12 complete systems at an estimated value of $1.6 billion.

jlens.gif (76576 bytes)


FAS | Space Policy | Star Wars | Programs |||| Search | Join FAS

Maintained by Steven Aftergood
Originally created by John Pike
Updated July 25, 1999 1:39:36 PM