News

Technion-manufactured diamonds launched into space
for endurance testing

The international team meets in the Schulich Faculty
of Chemistry (l-r) Prof. Alon Hoffman, Dr Irina Gouzman,
Ze’ev Shpilman, and Prof. Tim Minton

Doctoral student Ze’ev Shpilman, who is completing his PhD at Technion under the co-supervision of Prof. Alon Hoffman in the Schulich Faculty of Chemistry and Dr Joan Adler of the Faculty of Physics, says, “Diamond has many potential applications in space, such as protective coating for optical devices or radiation detectors. But in order to facilitate this, scientists must understand the interactions that take place between materials and the space environment.”

Shpilman, who holds Technion degrees in Physics and Materials Engineering, also works at the Space Environment Section at Soreq Nuclear Research Center (NRC). There, he is supervised by Dr Irina Gouzman - Hoffman’s very first doctoral student at Technion. The researchers found that diamonds are resistant to the space-simulated environment. Their findings went online in October 2009 in Applied Physics Letters. Now, they are trying out the material’s durability for real - in space. How long will the material last in orbit - on a satellite for example - when exposed to ultraviolet (UV) radiation and atomic oxygen (AO)?
The diamonds were grown in Hoffman’s Technion lab, and checked in a simulated space environment at Soreq NRC. The Israeli scientists teamed up with a group from Montana State University, where Prof. Tim Minton’s group also tested the diamonds with another kind of simulator, and included them in their set of samples for a NASA mission.

The homegrown diamonds were launched into space in November 2009, on mission STS-129 on board the shuttle Atlantis, bound for the International Space Station as part of the Materials International Space Station Experiment-7 (MISSE-7). The diamonds will reside in space for about nine months, and will be reexamined once they return to Earth.

(C) Seen through the Atomic Force Microscope at the
Space Environment Section, Soreq NRC, diamond
film grown at Technion and exposed to atomic oxygen
(AO) at Montana State University: (100) oriented
diamond facets exhibit less etching than (111)
oriented diamond facets

Diamonds have a crystallographic configuration and the direction of growth can be manipulated in the lab. The Technion scientists report that if grown in a specific direction, known as (100), then the diamonds show greater resistance to atomic oxygen (AO) than two other configurations tested, (110) and (111). “This means that the perfect space material can be grown to measure,” Shpilman explains. The Technion diamonds are made from Carbon-13, a natural, stable isotope of carbon and one of the environmental isotopes. “This will enable us to identify possible influences of carbon from another source in space,” he says.

Hoffman adds that the current venture is truly an international effort: “I’m from Buenos Aires, Irina is from Moscow, Ze’ev is from Tiberias, and Tim is in Bozeman, Montana. The product of our collaboration is now orbiting the Earth about every 90 minutes on board the International Space Station,” he says.

Space Control

Diamond, the most inert and hardest material in nature, with the best heat conductivity, exhibits unique mechanical, thermal, optical, and electronic properties. Although diamonds are dense, they are lightweight and easy to transport into space. The growing space exploration industry necessitates the development of the next generation of materials and material technologies that can withstand the harsh space environment that threatens its success.

At a height of 200 to 800 km above Earth, for example, atomic oxygen (AO) can produce serious structural, thermal, or optical degradation of spacecraft components. Due to the absence of Earth’s atmosphere, there is a great deal of ultraviolet (UV) radiation in space – a vast “ozone hole” if you will.

The MISSE test bed is attached to the outside of the International Space Station to check materials and coatings for the effects of AO, UV, direct sunlight, radiation, and extremes of heat and cold. Results will provide a better understanding of the durability of different materials with applications in the design of future spacecraft, communication and weather satellites, as well as enhance solar cell technology. Along with the Technion diamonds, the current experiments include analyses of spacesuit materials for use on the lunar surface.