Aerospace Relay Mirror System (ARMS)

[Lt-Col A. Tack]

This information is a few years old, but I don't think it has been well covered before, so here goes:

Twin-mirror laser-weapon relay hits the spot

18:04 09 August 2006
Jeff Hecht

A two-mirror relay system that could one day be used to destroy ground targets and airborne missiles with a high-intensity laser has been tested by the US Air Force Research Laboratory in New Mexico, US.

The tests carried were out in recent weeks at Kirtland Air force base, New Mexico, by Boeing and the US air force. They involved firing a laser with an output power of tens of watts at the relay system from a distance of about 5 kilometres.

The laser was then successfully redirected to a target a further 3 km from the relay. The mirror relay consists of two 75-centimetre-wide mirrors positioned close to one another and suspended 30 metres above the ground by a crane.

The long-term goal is to develop a high-altitude mirror system that could redirect powerful laser beams at targets beyond the direct line-of-sight of the laser's source. An air force fact sheet says such a relay could provide "a worldwide speed-of-light capability to the war fighter."
Airships and satellites

The input mirror collects light from the laser and and focuses it onto the output mirror, which directs it at the target. A series of gimbals stablise and point the mirrors and the final version will include an adaptive optics set-up, similar to that used in many high-power telescopes, to correct for atmospheric distortion.

A functional long-range laser would need a power output of between 100 and 1000 kilowatts and would therefore require larger mirrors. These would then need to be attached to airships, long-endurance aircraft, or satellites, to be practical.

Pat Shanahan, general manager at Boeing Missile Defense Systems, called the latest demonstration "a major step" because it "shows that a relay mirror system can receive laser energy and redirect it to a target, extending the laser's range."
Steady aim

Others, however, consider the demonstration only a minor advance. "Relay mirrors just add another set of systems requiring steady aim and split-second coordination," says Philip Coyle, a senior advisor at the Center for Defense Information, a military think-tank based in Washington DC, US.

By the air force's own admission, plenty of challenges remain. These include putting large enough mirrors in space, precisely tracking both the laser source and the target, managing waste heat, and aiming the mirrors precisely.

Link (http://technology.newscientist.com/channel/tech/weapons/dn9707-twinmirror-laserweapon-relay-hits-the-spot.html?feedId=weapons_rss20)

http://img259.imageshack.us/img259/2600/060811f6890s008eg0.jpg

A dual-mirror system, called the Aerospace Relay Mirror System, suspended from a crane at 100 feet above the ground, is being tested here. The system is a prototype designed to extend the range of high-energy lasers by receiving and redirecting laser energy. Developed at the Air Force Research Laboratory’s Directed Energy Directorate, an operational version might be suspended from a high-altitude airship at an altitude of 70,000 feet, where atmospheric turbulence, or jitter, is less of a problem for beam quality.

[Lt-Col A. Tack]

ST. LOUIS, Aug. 07, 2006

Boeing and the U.S. Air Force achieved major progress in their relay system development program by successfully redirecting a laser beam to a target using their Aerospace Relay Mirror System (ARMS).

The demonstration, conducted recently at U.S. Air Force Research Laboratory facilities at Kirtland Air Force Base, N.M., used a half-scale version of a strategic relay mirror payload that ultimately could be packaged and carried to high altitudes on airships, long-endurance aircraft or spacecraft. The payload could be used with airborne, ground-based or sea-based high-energy lasers to destroy ballistic missiles and other targets. Relay mirror systems will greatly enhance laser weapon system performance by reducing the atmosphere's effects on laser beams and extending their range beyond line of sight.

"This demonstration is a major step in the development of relay technology because it shows that a relay mirror system can receive laser energy and redirect it to a target, extending the laser's range," said Pat Shanahan, vice president and general manager of Boeing Missile Defense Systems.

During the demonstration, Boeing suspended the 15-foot-high ARMS hardware 100 feet above the ground using a mechanical crane. Testers fired a low-power, sub-kilowatt-class ground laser from several miles away at one of the ARMS payload's two 75-centimeter mirrors. The other mirror relayed the non-lethal beam to a ground-based target board about two miles away from the ARMS.

Boeing began its ARMS work four years ago under a $20 million Air Force contract. Now that the work is completed, the Air Force plans to use the ARMS hardware to establish a permanent test bed for relay system technology development.

Boeing Missile Defense Systems conducts its relay system work through its Directed Energy Systems unit, formerly called Laser & Electro-Optical Systems.

Boeing Press Release (http://www.boeing.com/ids/news/2006/q3/060807a_nr.html)

[khalifah]

Wow sounds like a lot of $$$$$

When I first read this...

A two-mirror relay system that could one day be used to destroy ground targets and airborne missiles with a high-intensity laser has been tested by the US Air Force Research Laboratory in New Mexico, US.


all I could think of was that "Ion Cannon" in the C&C series

[Lt-Col A. Tack]

AFRL Completes Aerospace Relay Mirror System Demonstration

by Plans and Programs Directorate
AFRL/XP

12/13/2006 - WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- AFRL's Aerospace Relay Mirror System (ARMS) program successfully completed a formal review of laboratory test results.

ARMS is a prototype laser relay system designed to redirect and focus the beam of a ground-based or airborne high-energy laser (HEL) onto a target, significantly increasing the HEL's range and lethality. Compared to a regular laser system, a redirected energy beam offers several advantages, including improved beam quality and the ability to hit beyond-line-of-sight targets. Relay systems will improve the engagement timeline, while increasing the standoff range for manned systems and serving as a low-cost force multiplier for HEL systems.

ARMS is a subscale prototype of a future laser relay weapon system. The ARMS technology includes dual line-of-sight pointing, energy capture and transfer, payload integration, and relay system operation and integration. The prototype system serves as a risk reduction test bed for relay system development, including airborne laser performance enhancement; active track; precision strike of time-critical targets; and persistent intelligence, surveillance, and reconnaissance.

AFRL's ARMS program met all hardware and software objectives and received approval to initiate its move to the Starfire Optical Range (Kirtland Air Force Base, New Mexico) for field tests. AFRL demonstrated the payload by performing tracking and pointing in several modes, characterizing all payload functions within the limitations of the laboratory environment. The laboratory tests' major achievement was the refinement of the cooperative tracking between the laser source and the relay receiver. Data analysis provided numerous details about system performance, including sensor performance, tracking overshoots, and settling time.

http://img170.imageshack.us/img170/2777/afg061213003vs9.jpg

Link (http://www.wpafb.af.mil/news/story.asp?storyID=123034996)

[Lt-Col A. Tack]

Shameless pimping of an old thread (http://www.militaryphotos.net/forums/showthread.php?t=119139), but it seemed relevant.

The acronym in question is FEL, short for Free Electron Laser


3.2 U.S. Perimeter Missile Defense

FELs are anticipated to achieve power levels beyond one MW within ten years, or sooner if pushed. This would make them capable of forming the basis of a U.S. perimeter missile defense. Being tunable, the FELs can be operated at eyesafe wavelengths making them deployable along the U.S. perimeter, even near population centers. As even higher power levels are desirable on targets, the perimeter defense concept is to spread the individual FELs along the U.S. perimeter such that any point of interest is in range of multiple FELs.

Key to the concept is minimizing the atmospheric affects of the perimeter based FELs by pairing them with a high altitude optical relay station airships as shown in Figure 8. This allows the FELs to point their beams near the vertical thereby minimizing the paths of the beams through the more dense portions of the atmosphere. The relay stations are mobile thereby allowing the light from the FELs to have minimal effects from clouds and turbulent air. In addition, using multiple FELs has the advantage of keeping the power density of the beams lower which will minimize if not eliminate the thermal blooming effects.

http://img139.imageshack.us/img139/9804/jlabcio0502fellaser0900rr4.png

Figure 8: Using multiple FEL optical relay mirror pairs, the U.S. perimeter can be protected by a very robust system.


The perimeter based FELs can be ground, sea or airship based. Ground based FELs have the advantage of easy access to electrical power but can frequently be limited by weather. Sea based FELs can avoid some of the weather but will have to pass their beams through the maritime atmosphere. Airship based FELs are able to avoid almost all weather and regions of turbulent air along the optical paths to the relay stations.

These FELs will be above most of the atmosphere where aerosols strongly influence the beam. Their fuel will easily last for weeks. With the reduction in atmospheric affects, the ranges and power densities on target substantially increase with the use of airship based FELs. Moving the FELs to the relay station altitude and eliminating the relay stations may be a possibility. Following is a simple implementation example: Assume that 3.3 MW FELs are deployed at an average liner density of one every 100 miles along the U.S. perimeter. Assume that each FEL optical relay station pair has a range of 300 miles.

The outcome is every place on the U.S. perimeter is within range of at least six of the FELs for a resultant 20 MW or more delivered on targets of interest.

Depending upon how the perimeters of Alaska, Hawaii and some of the U.S. territories are included, the U.S. perimeter can be considered to be up to 15,000 miles in length. In the implementation example, this results in the deployment of 150 FEL optical relay station pairs. If each pair averages $200M, including the system integration cost, the total cost of the system is $30B.

At the level of 150 FEL optical relay station pairs, the complexity of the system can be well managed. Modest increases in the density of the pairs in appropriate areas would establish significant redundancy. Switching from standby to fully operational takes only a few seconds. Being FEL based, the system could run in operational mode for days on end. Targeting, of course, is at the speed of light.

[Lt-Col A. Tack]

AFRL Seeks To Reduce Size Laser Relay Mirror for High Altitudes

10 AUGUST 06
By Jefferson Morris

AFRL seeking more power, smaller size with next laser relay

The Air Force Research Laboratory's (AFRL) Directed Energy Directorate at Kirtland Air Force Base, N.M., is embarking on a follow-on to its recently demonstrated Aerospace Relay Mirror System (ARMS) in an effort to prove that laser relay mirrors can be made deployable and operationally effective.

'Not our decision'

AFRL's future vision is for a system small enough to be carried on an airship that could relay and redirect high-energy laser beams fired from other platforms to destroy mortars, missiles or other targets.

AFRL plans to demonstrate the follow-on to ARMS in 2010, in a package compact and powerful enough to be considered for operational use by service leadership.

"The decision to make something operational is obviously not our decision," said Col. Gregory Vansuch, chief of the optics division at the Directed Energy Directorate.

AFRL recently wrapped up initial testing of ARMS at the Starfire Optical Range at Kirtland (DAILY, Aug. 8). Boeing was the lead contractor, and also is leading up the industry team working on the follow-on. The prototype ARMS relay consists of two independently pointed telescopes - one for receiving the laser and another for sending it back out. The entire apparatus weighed approximately 5,000 pounds.

The weight goal for the follow-on is 2,000 pounds and the team is aiming for 80-90 percent transmission efficiency, versus the 50 percent efficiency of the original prototype. The system is being designed to accept beams at tens of kilowatts of power, Vansuch said.

Separate power source

The system is being sized to fit under various tethered military airships, which typically float at 5,000 feet altitude. The relay mirror system features its own separate power source, which is more efficient than attempting to leech power from the laser beams it relays, Vansuch said.

Eventually, relay mirrors could be a candidate payload for platforms such as the Missile Defense Agency's (MDA) High Altitude Airship (HAA), which would operate at 70,000 feet where atmospheric distortion of the laser is reduced. Discussions also have taken place about using the relay to extend the range of MDA's Airborne Laser (ABL) system for boost-phase missile defense, according to Vansuch.

Testing of the first ARMS prototype stretched over several months, with the team performing tests whenever weather permitted. Invisible, low-power lasers were fired from the top of a hill at the Starfire range to the ARMS assembly, which was suspended on wires two miles away. The beam was then relayed to a distant target board.

While the smaller follow-on system is being developed, the current ARMS prototype will continue to be used as a test bed for tweaking the technology and exploring "other ways of doing the job better," Vansuch said.

Link (http://seattlewebcrafters.com/nsecc/?q=node/view/54)