Trelleborg Offshore (Mansfield, Mass., USA) reported on Jan. 3 that its high-performance glass microspheres have been specified by Lockheed Martin for use in the composite aeroshell system of the recently launched Mars Science Laboratory (MSL) Curiosity rover.
Designed and built by Lockheed Martin Space Systems, the aeroshell is a blunt-nosed cone that encapsulates and protects the Curiosity rover during its deep space cruise to Mars, and from the intense heat and friction that will be generated as the system descends through the Martian atmosphere. The capsule, which was launched by NASA, measures 15 ft/4.5m in diameter, the largest to date, and includes a composite load-carrying structure as well as thermal protection system.
Lockheed Martin provided the aeroshell to NASA's Jet Propulsion Laboratory, which manages the MSL mission and designed and built the Curiosity rover. MSL has the scientific goals of determining if the planet was ever habitable, characterizing the climate and geology of Mars, and preparing for human exploration.
The aeroshell is composed of a two part system; the front facing heatshield is a phenolic-impregnated carbon ablator (PICA) designed to take the brunt of the Martian re-entry, while the backshell has a super lightweight ablator (SLA0561V) material containing the Trelleborg Eccospheres as one of the ingredients. The SLA-561V ablator has flown on all of NASA's previous Mars entry vehicles.
Will Ricci, aerospace sales manager at Trelleborg Offshore, says, "Due to their high thermal resistance and lightweight, customizable properties, Trelleborg Eccospheres have served as a critical raw material component utilized in ablator, insulation and adhesive systems for space craft design since the dawn of the U.S. space program and we were a critical supplier to the NASA Space Shuttle program. With the Mars Science Laboratory the most ambitious Mars mission to date, it was imperative that the aeroshell was designed and built to withstand the demanding Martian atmosphere, without fail. As such, Lockheed Martin decided to make Trelleborg's Eccosphere glass microspheres a part of their mission critical backshell thermal protection system."
Rich Hund, MSL Aeroshell program manager at Lockheed Martin, comments: "The aeroshell is a vital part of the mission, forming a protective covering for the rover during the eight month voyage to Mars. Its main purpose is to protect the rover and descent stage from the intense heating of entry through the thin Martian atmosphere on landing day, ensuring it can complete its important mission."
Trelleborg Offshore's Eccospheres glass microspheres are hollow, thin-walled glass microspheres composed of sodium-depleted borosilicate glass. To the naked eye they resemble a fine, white, free-flowing powder, however magnification reveals them to be near perfect spheres. They are designed to help reduce costs, enhance properties and improve processability.
The glass chemistry and proprietary manufacturing techniques of Trelleborg's Eccospheres produce a product that is said to feature highly chemically inert sodium-depleted glass and exhibits superior thermal performance with material integrity up to 900°C/ 1652°F.