Thin-Film Tape Protects Mars Rover Wiring
- Friday, 01 June 2012
A high-performance thin-film product cre- ated specifically for NASA’s Jet Propulsion Laboratory in Pasadena, CA, is being used to ensure the electrical currents from the Mars Rover Curiosity’s different systems will not interfere with each other or impede the rover’s operation, while also protecting delicate cable systems from the harsh Martian environment. DUNMORE engineered the tape by combining DuPont Kapton polyimide film with a 3M adhesive and fiberglass reinforcement layer. The tape is one of the multi-layer insulation (MLI) products on Curiosity, which was launched in November 2011 from Cape Canaveral Air Force Station in Florida.
MLI is a type of thermal protection system (TPS) used on spacecraft, launch vehicles, the space shuttle, and the International Space Station. MLI insulation is typically found in blanket form, and consists of films and fabric constructions ranging from five to 40 layers, as well as highly specialized tapes used in edge binding and cable wrapping.
The goal of the TPS is to maintain equipment temperatures in very specific ranges during the mission life. Keeping this temperature range allows all electronic equipment, instruments, and systems to function in their optimal operating conditions. Curiosity’s TPS had its own set of challenges. For one, the lack of atmosphere on the red planet means there is less filtration between the space environment and the Martian surface. This leaves Curiosity’s instruments exposed to constant solar radiation.
MLI blankets used by Curiosity consist of multiple layers of highly reflective, low-emittance, or “E” materials. Similar to “Low E” windows in a house, emittance measures a material’s ability to reflect solar energy. A material that has low emittance properties will have highly reflective properties like a mirror, and would deflect heat, and more specifically, solar radiation in a space environment.
For optimum insulation performance, successive metalized layers are separated by materials with low thermal conductivity like Nomex or polyester netting. One layer of the MLI structure may reflect as much as 97 percent of incident radiation, and adding additional layers decreases absorbance between layers exponentially until it is completely dissipated by the time the energy would reach the protected component.
The Curiosity’s MLI system was designed to protect the rover’s electrical wiring from the constant exposure to radiation on the planet’s surface, and keep electronic equipment functioning properly for the intended life of the mission — just less than two Earth years — or even further.