Laser Mythology CSC 1992 SUBJECT AREA C4 EXECUTIVE SUMMARY Title: Laser Mythology Author: Major Roger D. Atkins, United States Marine Corps Thesis: There are too many Marines that do not fully understand current Marine Corps laser systems and how to best employ them to increase the combat power of the MAGTF. Background: The United States Marine Corps has invested tremendous amounts of money in laser systems for use on the battlefield. Science fiction writings, movies, and all to real science projects like the Strategic Defense Initiative have created myths about lasers. Very few Marines fully understand the capabilites of current battlefield lasers and how to plan for their employment. Recommendation: The United States Marine Corps needs to better educate Marines on the capabilites, hazards, and planning considerations for employment of lasers. LASER MYTHOLOGY OUTLINE Thesis Statement. There are too many Marines that do not fully understand current Marine Corps laser systems and how to best employ them to increase the combat power of the MAGTF. I. What comes to people's minds when they think of lasers. II. Capabilities A. Designating for precision guided munitions B. Observer and target location C. Marking targets for close air support III. Hazards A. Eye hazards B. Designator becoming a target C. Backscatter D. Prohibited Designator Zone IV. Training considerations and ranges A. Laser ranges B. MELIOS C. HGSS V. Planning considerations A. Copperhead Coverage Templates B. Copperhead Footprint Templates C. Pulse Repetition Codes Major Roger D. Atkins Conference Group 1 LASER MYTHOLOGY Man has been enthralled by the destructive potential of focused beams of light for many years. Perhaps the first description of a beam weapon used in battle comes from the Roman siege of Syracuse in 212 B. C. Ancient sources say that Archimedes devised a hexagonal mirror, and at an appropriate distance from it set small quadrangular mirrors of the same type, which could be adjusted by metal plates and small hinges. This contrivance he set to catch the full rays of the sun at noon, both summer and winter, and eventually by reflection of the sun's rays in this, a fearsome firey heat was kindled in the barges, and from the distance of an arrow's flight he reduced them to ashes.(1: 17) Mention lasers and this picture of ships being incinerated is what comes to many peoples' minds. Science fiction writings, movies and all to real science projects like the Strategic Defense Initiative continue to reinforce this picture. Unfortunately this has created many myths in people's minds concerning lasers, especially those in use on today's battlefield. There are too many Marines that do not fully understand current Marine Corps laser systems and how to best employ them to increase the combat power of the MAGTF. It is time to separate myth from reality so that these systems can achieve their full potential. MYTH ONE ( Lasers are only useful in killing tanks and point targets.) It is doubtful that a portable battlefield laser that can kill a tank all by itself will ever appear in our career. The problems of power and fire control are just too difficult. The war in South West Asia highly publicized one use of the laser, the designation of targets for attack by precision guided munitions. I do not wish to demean this capability, since when properly employed a laser designator gives the maneuver commander a three to five thousand meter anti-tank system that has no visual firing signature. However, this is not how lasers were first used in the military nor their primary use. The first operational use of lasers was as battle field range finders. Today this is still their most important and useful function. This allows first round hits from modern fighting vehicles and more importantly more lethal fires from a forward observer. It allows a maneuver commander to direct the attack of targets with "dumb" iron bombs and projectiles with an unprecedented degree of accuracy. Let's use forward observers as an example. Forward observers are just one part of a field artillery team. This team is made up of the forward observer, the fire direction center, and the guns. The team's sole function is to provide accurate and timely fires in support of a maneuver commander. Unfortunately the weakest member of this team has been the forward observer. No matter how sophisticated we made our fire direction computers, or precise our guns we could not eliminate the human error that is caused by the forward observers inability to always accurately locate a target. The "Army Training Study-Forward Observer" in October 1978 evaluated 124 FOs, officer and enlisted, from nine battalions at Fort Carson and Fort Hood to determine their ability to locate themselves and locate targets and correlated this to their unit training in observed fire. On the average, the FOs could not meet standards or target or self location. The target location errors ranged from 400 to 700 meters, and self location errors were from 300 to 400 meters.(2: 55) The laser range finder designator (LRDM) has given the forward observer the ability to accurately locate himself or a target within 10 meters. This translates into more accurate and responsive fires to a maneuver commander and saves ammunition that would be wasted on lengthy adjustments. It also allows the placement of "dumb" high explosive projectiles in more select and lethal points within a target array. Another use for the laser on the battlefield is to mark targets for close air support aircraft. Traditionally an aircraft or indirect fire weapon system would deliver a white phosphorus round as close to the target as possible in order to help identify the target to attacking aircraft. Unfortunately, these marking rounds could be as much as 300 to 500 meters away from the target and of little assistance to the pilot. With a laser designator and an aircraft equipped with a laser spot tracker (LST), or system that can see laser energy, the forward air controller can illuminate the target with laser energy which can be picked up by the attacking aircraft once again making the delivery of "dumb" iron bombs more accurate. Laser designators were used in South West Asia to mark targets for close air support. Some missions were successful, some were not. A consideration to be kept in the back of the mind of all commanders and lasers users is that the laser beam spreads as it travels down range. That pencil sized beam that leaves the laser is approximately 5 feet in diameter at 8 kilometers. An operator will have to aim lower on the target than usual to prevent laser "spill over." Even with "spill-over" and "underspill" the laser is still more accurate than the 500 meter WP mark. Another consideration is that laser beams can be disrupted by smoke, fog, or haze. Just because you can see it through your thermals or optics doesn't guarantee that you can lase it.(7: 41-42) MYTH TWO (Laser range finders and designators can burn cloth, skin, and flammable materials.) Ground laser range finders and designators are not harmful to skin or flammable materials. However, lasers of all types are very hazardous to the human eye and the designators themselves can become targets when precision guided munitions are not properly employed. The human eye is very susceptible to laser energy. This damage is caused by the cornea or eye lens transmitting the energy onto the retina of the eye. This damage can vary from flash- blindness, which is temporary, to hemographic lesions which can result in total blindness. The principle dangers to the eye result from looking directly back at the laser, and from reflections off mirror like reflectors. Binoculars and similar optical devices can increase the hazards. This optical hazard can exist as far away as 80 kilometers from the laser. Ballistic laser eye protection glasses, visors, binoculars with laser filters (such as the M22) can reduce these hazards. (4: 56) Precision guided munitions can pose a threat to the designator when the angle formed between the designator to the target and the delivery system to target exceeds sixty degrees. Precision guided munitions guide on laser energy reflected back from the target into the field of view of the optical seeker. Because of the highly directional nature of the beam, the seeker does not see the beam itself but only those rays of the beam that are reflected off the target. Unfortunately as the beam passes through the lenses of the designator a small amount of laser energy is reflected giving the designator a glow or aurora. If the angle between the designator and the munition in relation to the target exceeds sixty degrees the laser spot on the target can become masked so that very little of the reflected laser energy is being picked up by the seeker. Also, at these large angles the designator can come into the field of view of the seeker. With little or no reflected energy being picked up by the designator from the target and the designator coming into its field of view the seeker will attempt to guide the munition to the strongest source of reflected energy which is now the designator. The second hazard is caused by a phenomena known as backscatter. If the line of sight between the laser and the target is not cleared of grass, bushes or trees some of the laser energy can be reflected off these objects. This will cause a "spot" short of the target upon which the laser seeker can guide. This is especially hazardous when designator is on the line between the delivery system and the target. This can cause the munition to land short and endanger the designator. Joint Pub 3-09.1, Joint Laser Designation Procedures, addresses this area between the delivery system and the target under Hellfire safety considerations. Labeled a "prohibited designator zone", no designators are allowed in this zone due to the possibility of the missle tracking backscatter energy. All these hazards can be avoided. There must be close coordination between the delivery system and the designator so that the angle between the designator and the delivery system does not exceed sixty degrees. Designators should not be in the prohibited designator zone, and the line of sight between the designator and the target area must be cleared of all possible obstructions. Even a few blades of grass can be hazardous to your health. MYTH THREE ( Lasers are more dangerous than other weapons and thus laser safe ranges are harder to build.) A laser range finder designator is a direct fire weapon system with an eye hazard range in excess of eighty kilometers. Lasers, like a rifle or a pistol, must be respected. In 1990 the United States Army issued a message that stated soldiers should not look in the firing port or "business" end of a laser while pressing the firing button. This is equivalent to saying you should not hold a pistol to your head while pulling the trigger. This may sound humorous, but unfortunately the message was the result of soldiers in two separate instances injuring their eyes by looking in the laser firing port of a laser range finder and pulling the trigger. Laser firing ranges are very similar to any other direct fire weapon range. It contains a buffer zone to prevent inadvertent lasing of targets that might lie outside the safety fan and a backstop to catch any stray laser energy that might miss the target. Procedures for the construction of laser safe ranges and the duties of the laser range safety officer are contained in Army Regulations 385-63, Chapter 19 and Army Regulations 385-30. (6: 16-19) There are two new developments that might one day allow us to operate lasers without the restrictions of ranges. HGSS, Hellfire Ground Support System, and MELIOS, Miniature Eyesafe Laser Infrared Observation Set, are two new systems being fielded by the United States Army that will greatly reduce laser safety hazards in peacetime and combat. HGSS was designed to help train designator operators to track moving and stationary targets. This system consists of an eyesafe laser designator, approximately the same size and physical characteristics as a real designator, and a sensor array that can be put on any vehicle. Once installed the operator can then practice tracking the vehicle and illuminating the sensors. The use of actual combat vehicles lends realism to the exercise. This system was used in South West Asia for training. One division, which successfully destroyed 9 out of 10 targets with cannon launched laser guided projectiles, credited its success with PGM's to this system. MELIOS is a replacement system for the AN/GVS-5 laser range finder. Utilizing a Raman-shifted Nd:YAG laser and blocking filter this system will provide an eye safe laser for use in peace time and combat. Application across the spectrum of laser range finders and designators will significantly enhance training and reduce the need for laser ranges.(3: 174) MYTH FOUR (Laser guided weapons are simple to employ and always hit the target) Many people think that laser guided weapons are silver bullets. They like to believe that they are simple to employ and always hit the target. When they don't live up to these expectations people lose faith in them. The 155 mm cannon launched laser guided projectile (COPPERHEAD) was one such weapon system. When developed it advertised a 90% probability of kill. After fielding this probability of kill based on rounds fired in support of unit training went down to around 60%. Because of this "perceived" reduced accuracy, procedures were established to fire two rounds at each target in order to ensure its destruction. Recently it has been discovered that the inaccuracies or low probability of kill was not from the weapon system, but from poor planning. Prior planning for the use of laser guided munitions is critical to their success. This planning must take into account the position of the designator in relation to the delivery system, for both accuracy and safety, the size of the area which the seeker can see and make course corrections, and the proper proper pulse repetition frequency for the designator and seeker. There are two templates that assist in planning laser engagement area for the observer. The Copperhead Coverage Template has been designed as a position selection aid to be used by fire support coordinators in selection of forward observer locations when using cannon launched laser guided projectiles. It is a tool that rapidly discriminates between can shoot and can't shoot engagement areas. Aircraft can easily change positions when the firing angle is unsuitable for accuracy or safety. Cannon units cannot. This template is based on experience that has shown that target engagement angles between the designator and firing unit that exceed 45 degrees adversely affect accuracy and that the maximum effective range for designator operators is 3 kilometers for moving targets and 5 kilometers for stationary targets. Procedures for use of this device are contained in FM 6-20-40, Fire Support For Brigade Operations Heavy. When properly used this device can determine the best position for designators, which firing assets best support them, and whether an designator or firing unit must be relocated. (5: 26) The Copperhead Footprint Template is used to help select adjusting points within the engagement area designed by the Copperhead coverage template. On the downward leg of the Copperhead flight, the round acquires the reflected laser energy and begins to guide on the target. This area in which the seeker can acquire and guide is limited. This oval shaped area is called a footprint. Although the round can maneuver to the outside area of the footprint, the greatest chance of hitting the target is when it is near the center of the footprint. Copperhead Footprint Templates were developed to accurately portray this footprint or engagement area around each adjusting point. Copperhead M712,TE 6- 6-1, NSN 1220-01-224-2588 contains 12 templates numbered A-L which are designed based on target cloud height, the gun target range, visibility, and angle of fire (high or low). Procedures for the use of these templates is contained in FM 6-30, Observed Fire. When used by fire support coordinators and designator operators these templates can greatly increase the missions chance of success. (6: 22-24) Though there are no tools to assist the planner, a very important consideration is the pulse repetition frequency code. Laser designators and use a pulse coding system to ensure that a specific seeker and designator combination work in harmony. (4: 1) The planner must be concerned with the limited number of codes available, their allocation, assignment, and characteristics. Laser codes, depending on the equipment, are either three digits or four digits. If it is a four digit code the first digit is always the numeral 1. The laser codes vary from 111-488 (Band 2) to 511-788 (Band 1). These numbers represent the nano- seconds of delay between the laser pulses. The smaller the number, the smaller the delay. The result is that band 2 pulse rates result in more laser energy striking and reflecting off the target giving the seeker a better laser spot to guide on. As a result band 2 pulse rates are better for adverse conditions and when the mission has a high priority. If you throw in the fact that there are only six hundred and seventy-seven codes available (788- 111=677) on any given day to U.S. forces, you soon see that priorities should be set for the distribution of these codes. This is where allocation and assignment becomes important. In a MAGTF the senior fire support coordination center (FSCC) allocates different blocks of codes to artillery ,air ,and naval gunfire assets. The FSCC will also keep a block of codes for MAGTF special use. Fire support coordinators in subordinate units not only coordinate codes with adjacent units, they monitor missions and ensure proper code coordination between the delivery unit and the designator. Normally the delivery system will tell the designator which code to use. There may be occasions where a special code for that mission is assigned to the designator and delivery system from the block reserved by the MAGTF FSCC. All pulse repetition codes can the used for laser designation. However, the characteristics of band 2 codes make them more suitable when designating for laser guided munitions. (4: 1-3) CONCLUSION The United States Marine Corps has invested tremendous amounts of money in laser systems, both air and ground. There are too many Marines that do not fully understand Marine Corps laser systems and how to best employ them to increase the combat power of the MAGTF. The myths generated by science fiction tend to cloud the facts of reality. A great deal of this mis-understanding is due to a lack of training and education. Lasers are considered to difficult and ranges to operate them to hard to build. This just is not so. Treated with the respect given any other direct fire weapon system they can be used safely. They are not silver bullets, but require planning to successfully employ them. Used properly they can give a maneuver commander the capability to surgically shape the battlefield, or silently assinate an unsuspecting commander. The United States Marine Corps is laser equipped. It is time we became laser capable. BIBLIOGRAPHY 1. Hecht, Jeff. Beam Weapons. Plenum Press. 1984. 2. Kelly, Michael, B.. "Why FO's Can't Shoot." The Field Artillery Journal. (July 1979) 54-56. 3. Ogorkiewicz, R. M. . "Eye Safe Neodymium Lasers." International Defense Review 2. (1990) 174-175. 4. The Jiont Chiefs of Staff. Joint Laser Designator Procedures. Joint Pub 3-09.1, (1 June 1991) Chapter IV-V. 5. United States Army. Headquaters Department of the Army. Fire Support for Brigade Operations (Heavy). FM 6-20-40, (January 1991) Appendix H. 6. United States Army. Headquarters Department of the Army. Observed Fire. FM 6-30, (29 April 1991) Appendix A. 7. Ursey, Floyd, J. Jr. Maj, USMC. "Marking the Battlefield for Close Air Support." Marine Corps Gazette. (February 1992) 39-42.
