January 2003
 

Direct energy weapons close gap

Dr. Gerd Wollmann on laser technology and high-power microwave

They are not only an admired and essential part of science fiction movies like Star Trek: direct energy weapons used successfully by the likes of Captain Picard and his predecessor Captain Kirk to protect the spaceship Enterprise against the powers of evil in space. Science fiction symbolism and energy weapons technology have also been used very cleverly in the most recent Star Trek movie Nemesis. However, direct energy weapons are not just something from the realm of science fiction: they have become reality, albeit in a very different form to that presented in the world of movies.

In the following article, Dr. Gerd Wollmann of Rheinmetall W&M GmbH explains that such weapons actually already exist in the armed forces and will become more and more normal in the years to come. The 46 year-old physicist and defence expert who has been with Rheinmetall since 1987 and has been in charge of the System Analysis/Simulation department since 2001 outlines the work of the 12-strong team of specialists in the field of energy weapons, with a focus on Medium Energy Laser and High-Power Microwave weapons.
 

  Dr. Gerd Wollmann

Looking at military operations of the recent past, present military developments and predictions for the next ten to twenty years, the following main operational requirements are evident:

• Information gathering by all kinds of sensors, networking of data and communication on the one hand, and countermeasure against sensors and communication/data networks on the other hand;
• Avoidance of collateral damage;
• Capability of downscaled escalation of conflicts, i.e. keeping the weapons in proportion to the conflict e.g. by using non-lethal weapons* before using the classical lethal weapon system.

New weapon systems need to be developed to tackle these new tasks. Direct energy weapons have become an important area of defence systems research in western countries, all the more so since the performance of recent peacekeeping missions, and Rheinmetall is actively involved in these development activities. The Rheinmetall DeTec group is working on Medium Energy Laser (MEL) and High-Power Microwave (HPM) energy weapons. The Ratingen-based group has been carrying out related theoretical and experimental research, conceptual and integration studies funded by the group itself and others for more than 15 years now. These activities are being carried out under the leadership of Rheinmetall W&M GmbH.
 

Future: Rheinmetall W&M GmbH is focusing on the field of medium energy laser weapons – pictured here is a study in connection with a recoilless machine gun and rocket launcher – since, on account of their size, these are particularly well suited as add-on weaponry and also self-protection systems – in addition to tube weapon and rocket systems – for armored combat vehicles or in air defence systems.

In Germany, the companies Rheinmetall W&M GmbH and Diehl Munitionssysteme GmbH & Co. KG signed an agreement at the end of last year covering close cooperation between the two in the field of High-Power Microwave weapons; in future, both companies will tackle the subject jointly as partners.
 

Laser Weapons

Lasers have been put to many military uses for many years, for example:

• laser range finders,
• laser target designators for guided missiles, bombs and shells,
• laser radars,
• countermeasure radars (e.g. to protect aircraft against approaching missiles),
• lasers for the remote detection of warfare agents,
• laser vibrometers for reconnaissance,
• laser scanners for submarine and mine detection,
• laser weapon system simulators.

Some countries have been carrying out R&D activities relating to the use of lasers as weapons during the last decades. Especially the USA and former Soviet Union conducted intensive work on such systems in the seventies and eighties of the last century. Individual systems have already been tested and introduced in small quantities, and related work is continuing today, e.g. to destroy launching rockets during their boost phase.

Laser weapons are directly aimed energy weapons: the laser beam propagates at the speed of light. Conventional terms like lead and elevation do not apply to such weapons. The radiation is absorbed by the target and transformed into heat. This causes the optics and opto-electronic components or structures to be destroyed. Laser weapons are capable of disturbing (low-energy laser) or destroying (medium-energy laser) opto-electronic equipment at tactical distances. High-energy laser weapons can destroy light structures at strategic distances.

Low-energy lasers result in a mission kill, medium-energy lasers in a mission kill, a mission abort and a fire-power kill while high-power laser devices will destroy the target (catastrophic kill, e.g. of a rocket that is being launched).

Rheinmetall DeTec is concentrating on the field of medium-energy laser weapons since, on account of their size, these are particularly well suited as add-on weaponry and also self-protection systems – in addition to tube weapon and rocket systems – for armored combat vehicles or in air defence systems to provide protection against guided missiles, unmanned air vehicles, helicopters and cruise missiles. The main emphasis is on pulsed laser systems that are superior to continuous wave lasers in terms of interaction characteristics with the target and also the transmission properties of the laser beams through the atmosphere.

In recent years, extensive experimental studies have been conducted into all areas needed for a laser weapon, covering aspects like laser sources and questions concerning the transmission of laser radiation through the atmosphere, beam-forming and beam-guidance, target acquisition and automatic aiming as well as laser weapon concepts.

Laser weapons offer various advantages over conventional weapon systems, i.e. both guns and rockets. One of the important advantages of the laser weapon is its enormous speed; as mentioned, energy is transmitted at the speed of light. Another asset is that no heavy guns or rocket aiming systems have to be transported when laser weapons are used since these require "only" the relatively light mirror systems; this is something that can be implemented quickly. Moreover, laser weapons can be used against targets that can only be detected very late due e.g. to terrain conditions and can then no longer be engaged with conventional weapons.
 

Designed by experts from Rheinmetall "Defence" sector: Integration study with the three weapon systems MEL (Medium Energy Laser), recoilless machine gun and rocket launcher in an unmanned turret of an all-electric vehicle. Except for the power supply, all of the components needed for the laser weapon are integrated in the turret.

If – as is the case with the Rheinmetall solution – electrically operated solid-state lasers are used as laser source, these allow a much compacter design than gas laser systems and also offer further benefits. The costs per engagement process are nearly zero since only energy stored in a capacitor block (e.g. from the electrical network of a vehicle) is utilized, making munitions logistics with ammunition bunkers in the vehicle superfluous. The crew is not exposed to any danger from emitted gases (e.g. after a hit).

Medium-energy laser weapons are so-called non-lethal weapons. The laser beams are bundled so well that targets can be hit with pin-point accuracy. Collateral damage is therefore avoided.

Current activities concern the development of a technology demonstrator for a medium-energy laser weapon. This demonstrator should be available in three to four years time, and will contain all individual technologies hitherto investigated and deemed positive. Functional proof from target acquisition through to target engagement will be furnished at the Rheinmetall firing range in Unterlüß; an extension of the existing laser range to greater firing distances is planned. Following the successful presentation of the demonstrator, it is planned to produce a system demonstrator, i.e. to integrate the medium-energy laser weapon e.g. in an armored vehicle. It is conceivable that an MEL system should be mature enough for introduction in the armed forces by the year 2012.

The know-how collected in recent years can be used not only for military and weapons applications. Modern-day police operations (police actions, object protection) and anti-terror missions of special forces are exposed to threats from sniper gunfire, anti-tank guided weapons and portable anti-aircraft rocket systems. Attacks are nearly always preceded by observation with optical devices. In the past, it was practically impossible to detect observers or snipers before they opened fire. An active laser system capable of detecting reflections from optical systems and indicating the position is an important asset in this connection. It is planned to bring a sniper detection system onto the market very soon; as requested by the special forces, this system will be portable and cover the relevant distances.
 

High-power Microwave

Typically, high-power microwave systems operate in the frequency range between 100 MHz and 5 GHz; depending on their intensity, they will disturb or destroy individual military and civil components/ systems. A fundamental distinction is made between narrow-band and wide-band microwave sources:

• Narrow-band sources produce the radiation almost on a fixed wavelength. There are considerable physical limitations regarding the possibility of changing such a wavelength quickly into a large frequency range. In terms of weapon systems, this means that the system to be engaged has to be known very well. Only the frequency at which the absorption is particularly high is allowed to enter the system (the absorption being highly dependent on the aspect angle). If a system is fought with the wrong wavelength or if the target object is located at an unfavorable aspect angle with reference to the source, the microwaves will not enter the system and consequently remain ineffective.
   
• Wide-band radiation sources avoid this problem and give the aiming system a broad frequency spectrum. Frequencies that can be absorbed are absorbed and have the desired effect if powerful enough.

The companies Rheinmetall W&M GmbH and Diehl Munitionssysteme GmbH & Co. KG are concentrating on pulsed microwave sources that can be integrated as single pulse systems in e.g. artillery grenades or rocket systems, and as repeating sources in ground-based, airborne and sea-based vehicles. Particularly small sources, so-called semi-conductor sources can even be implemented as "suitcase" solutions for anti-terror operations. The radiation can be focussed on the target object – for instance, a house to switch off the communication facilities (mobile phones, telephones, TV or PC) or a "forgotten" suitcase at airports to inactivate any ignition devices. Persons escaping in vehicles can even be stopped by disturbing or destroying the electronic systems of the vehicle. For all these applications, appropriate sources have been or are being procured or further-developed, and tested in the HPM laboratories at Unterluess/Roethenbach and the Technical Center of the German Army.
 

A possible solution for the future: a high-power microwave weapon integrated in a Wiesel-type vehicle. The companies Rheinmetall W&M and Diehl Munitionssysteme are concentrating on pulsed microwave sources that can be integrated as single pulse systems in e.g. artillery grenades or rocket systems, and as repeating sources in ground-based, airborne and sea-based vehicles.

As with laser weapons, it is planned to have appropriate high-power microwave systems available in the short term (e.g. compact portable systems) or medium term (for integration in vehicles). HPM artillery rounds with firing velocities of up to 16,000 g obviously involve considerable demands on the sources, power supply and antenna systems. Nonetheless, such systems could be mature enough to enter the services by about 2007.

To sum up, it should be noted that direct energy weapons are not all-rounders; they will neither compete with conventional systems nor will they replace them. What they can do is close the gap in existing structures (dead zones of rocket systems, inadequate resistance to saturation attacks, inadequate reaction capability against targets appearing suddenly at close range). They will also expand the spectrum of tasks (non-lethal weapons, no collateral damage, de-escalation particularly for peacekeeping missions) and improve self-protection. Applications derived from the weapons concept but not of a purely military nature also allow product and system concepts for anti-terror operations.

Dr. Gerd Wollmann
 

* The term non-lethal weapons means all technical devices capable of preventing a person (system) or a group of persons from performing hostile actions without having a permanently damaging or life-threatening effect.