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Soldier Personnel Protective Equipment from High Energy Lasers

Description:

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Directed Energy OBJECTIVE: A lightweight and wearable Soldier PPE able to neutralize high energy laser threats upon impact and, incidentally, able to alert the wearer of the presence of such threats DESCRIPTION: High energy laser (HEL) threats are expected to be deployed in the future battlefield. They exhibit many compelling features including speed-of-light engagement, a deep magazine, and limited protection against the highest powers. The threat mechanism is via optical damage and intense thermal damage. These qualities behoove the development of PPE for Soldiers. A solution to this problem does not have to provide complete protection against HELs, even partially protection can buy Soldiers enough time to evade or engage the threats. In addition, the wavelength could be in the near infrared (NIR), such as with a Nd:YAG laser, making it undetectable visually via scattered light. A PPE system was developed for industrial users of high energy lasers [1]. The PPE proposal here could involve a wearable for the Soldier or a shield-like product. HELs can have irradiances greater than 10 W/cm2 or powers greater than 500 W. Even materials with extremely small amounts of absorption in the visible or NIR, such as noble metals, will lead to optical power absorption, heating and thermal runaway as the material gets damaged. Damage leads to further absorption as the material’s absorption coefficient increases. Energy can be reflected away and/or spread around to a larger volume to prevent damage. The HEL PPE must demonstrably reduce the burn injury/damage to both the wearer and the article itself. The wearable must address the following when exposed to a visible or NIR laser of irradiance 100 W/cm2: not allow the laser to penetrate to the skin before 1 minute, result in an inner surface temperature less than 44 °C, i.e., the burn injury threshold, for at least a minute, not catch on fire before either the inner surface temperature is greater than 44 °C or before 1 minute. Proposers should note that HEL PPE that simply reflects all the energy as may cause injury to nearby bystanders. The HEL PPE must be wearable, flexible, able to be carried by an individual Soldier, and greater than 1 m2 in area. ASTM standards for thermal protection should be followed including ASTM 1959, 1930, 1358, and C1055-20 [2—4]. PHASE I: During Phase I the contractor shall research and develop innovative approaches to HEL personal protection. Throughout the Phase I, monthly reports detailing technical and programmatic results shall be delivered. End of products shall include a technical report detailing proposed materiel solution with expected protection levels in terms of inner surface temperature reached after 1 minute of exposure to vis or NIR laser of 100 W/cm2 and expected length of survival against exposure to an HEL. Proposed solution should address wearability, flexibility, weight, and size. Ability to preserve situational awareness and increase lethality of the Soldier should be supported with sound reasoning and substantial evidence. PHASE II: The vision for this R&D is a baseline for HEL PPE for Soldiers and shielding material for equipment such as UASs. The end-state is the ability for Soldiers to have extra time while irradiated to evade or engage. The technology developed here would be transitioned to a Program of Record through the Product Manager (PM-SCIE). Additionally, a commercial need for such PPE exists (industrial users of lasers or other intense sources of heat and radiant energy) and would help in driving down fabrication costs as the market grows. PHASE III DUAL USE APPLICATIONS: The vision for this R&D is a baseline for HEL PPE for Soldiers and shielding material for equipment such as UASs. The end-state is the ability for Soldiers to have extra time while irradiated to evade or engage. The technology developed here would be transitioned to a Program of Record through the Product Manager (PM-SCIE). Additionally, a commercial need for such PPE exists (industrial users of lasers or other intense sources of heat and radiant energy) and would help in driving down fabrication costs as the market grows. REFERENCES: 1. C. Hennigs, M. Hustedt, S. Kaierle, D. Wenzel, S. Markstein, A.Hutter, “Passive and Active Protective Clothing against High-Power Laser Radiation”, Physics Procedia, Vol 41, pp 291-301 (2013) 2. ASTM C1055-20 “Temperature for Bioeffects” 3. ASTM F1959 “Standard Test Method for Determining the Arc Rating of Materials for Clothing” KEYWORDS: High energy laser; personal protective equipment; thermal
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