Micrometeoroid/Orbital Debris Protection (MMOD)
Micrometeoroid Orbital Debris-IMLI is a unique system that provides both thermal insulation and MMOD shielding. MMOD-IMLI is an integrated system based on proprietary discrete spacer technology, it combines the thermal radiation barriers of IMLI, the precise control of layer spacing with polymer spacers, and high strength ballistic Kevlar and Nextel layers. MMOD-IMLI utilizes IMLI’s structural strength to support ballistic layers, providing both thermal insulation and micro-meteoroid and orbital debris protection. MMOD-IMLI has 24% of the mass of a multishock shield with equivalent stopping power.
MMOD-IMLI test coupons were fabricated and used for Hyper Velocity Impact (HVI) testing at JSC/White Sands Test Facility. A preliminary model of the MMOD-IMLI shield was combined with a model for an Orbital Fuel Depot mission by Eric Christiansen and Dana Lear of JSC to develop preliminary Ballistic Limit Equations, and actual hypervelocity impact results indicated MMOD stopping power matched the BLE models.
The team (NASA JSC and Quest) worked collaboratively to establish an Orbital Fuel Depot (OFD) mission profile, analyze the fluence and impact risk of that mission, and develop a finite element model in order to predict the Probability of No Penetration (PNP). Inputs were established for an OFD based on an extended Centaur cryotank set in a selected orbit. MMOD fluence and impact risk analysis were performed by Dana Lear and Eric Christiansen of JSC, who developed an OFD Finite Element Model and used Bumper-II MMOD risk analysis code to estimate the risk performance of an MMOD-IMLI shield.
The mass of the MMOD-IMLI coupon was 8.0 kg/m2, compared to a standard Whipple shield mass of 15 – 20 kg/m2 to stop a critical diameter particle of 6.3mm for the selected PNP. Feasibility of the MMOD-IMLI system was successfully proven, a prototype was demonstrated in a laboratory environment for TRL3, and MMOD-IMLI continues to be a novel concept that could provide both thermal insulation and effective MMOD shielding in a single relatively lightweight system.