Reducing the shake, rattle, and roll on objects deployed in space

  • Published
  • By Michael P. Kleiman
  • Air Force Research Laboratory Space Vehicles Directorate
Current deployment mechanisms operating aboard spacecraft primarily consist of heavy springs, which when activated, inflict shock to components such as solar arrays and antennae, often hindering the equipment's efficiency in the cosmos environment, but a developing technology to be evaluated in the near future aboard the International Space Station could put a halt to the not-so-good vibrations.

Comprised of a mixture of carbon fiber strands and an epoxy resin, the Elastic Memory Composite Hinge operates by temperature application, becoming pliable when heated and then maintaining a stiff position while cooling.

"The Elastic Memory Composite Hinge serves as a low-mass, low-complexity replacement for current deployment mechanisms," said 1st Lt. Corey Duncan, EMCH program manager, Air Force Research Laboratory's Space Vehicles Directorate, Kirtland Air Force Base, N.M. "Additionally, these hinges will mitigate spacecraft shock that is typically experienced in deployment devices."

Employing monies awarded by the federal government-administered Small Business Innovation Research program and other funding sources since 2000, Composite Technology Development, Inc., Lafayette, Colo., designed, advanced, and tested the EMCH system, which has demonstrated a gradual, controlled functionality that protects, not harms, the item it will deploy. For example, during launch when intense shaking can occur within the rocket body, the hardened compound material restricts the movement of deployable objects, but once the spacecraft reaches orbit, the opposite transpires as increased temperatures from the sun or an internal energy source placed on the apparatus creates elasticity.

Following almost four years of evaluating and proving EMCH's viability, CTD, with oversight by AFRL's Space Vehicles Directorate, produced a cost-effective, low-risk, and flight-ready experiment to validate the hinge's predicted performance, as well as opted to transition the technology to the Dept. of Defense, the National Aeronautics and Space Administration, and industry for opportunities to exhibit the product's capability in orbit. Shortly thereafter, during the DOD-sponsored Space Experiment Review Board, the decision was made to manifest the EMCH on the International Space Station, and in September 2006, following multiple reviews, NASA cleared the trial for inclusion onboard Space Shuttle Mission STS-116, for transport to its new home three months later.

"The Space Vehicles Directorate provided technical supervision and guidance in the development, as well as in the production of the EMCH experiment. The organization worked closely with Space and Missile Systems Center's Space Development and Test Wing to place the innovative technology on the ISS where it will be validated," said the EMCH program manager. "In my role as the program manager, I have ensured a smooth transition from CTD to NASA."

Once the Space Shuttle Discovery docked with the ISS in December, one of the eight astronauts comprising the crew manually transferred the EMCH demonstration, which involved a clear self-contained, Plexiglas box, measuring 10 inches by 20 inches by 17 inches, featuring three sets of tests with two hinges apiece. To date, there have been no data returns from the triple trials, but the ISS residents are scheduled to evaluate the EMCH during one of their upcoming "Saturday Science" sessions. In addition, another version of the experimental hinge deployed the experimental solar arrays on TacSat-2, a micro satellite also administered by AFRL's Space Vehicles Directorate, which launched in December for a planned six to 12-month mission. Nevertheless, the EMCH's role on TacSat-2 was limited, as the mechanism did not impact the spacecraft's operations, nor did it provide information to the ground control team.

"If the EMCH's performance is validated during its stint on the International Space Station, it will reduce the risk of shake, rattle, and roll to future space programs, as well as to the next generation of vehicles operating in the cosmos. CTD's innovation is a highly cost-effective way of validating elastic memory composite technology and accelerating the transition of this technology to the warfighter," said 1st Lt. Duncan. "In the end, the EMCH provides DOD and civilian space programs with a more reliable and less complex deployment capability for their spacecraft."