Old as New – Refurbishing SUBSA for Materials Payloads

The stage is now set for the Orbital ATK Cygnus vehicle to make its seventh cargo resupply mission (CRS-7) to the International Space Station (ISSInternational Space Station). Set to launch on April 18, 2017, the Cygnus capsule, which will launch aboard United Launch Alliance’s Atlas V rocket, contains more than 40 investigations sponsored by the ISS U.S. National Laboratory. The payloads on this flight include cancer drug development research, novel satellite platform technologies, and educational projects, one focusing on the study of DNA changes in astronauts.

A project focusing on astronaut health is appropriate, given that this spacecraft delivery is named in honor of former astronaut and U.S. Senator John Glenn, a distinguished military and political figure with a lifelong love of spaceflight exploration. Glenn is remembered for his exhilarating orbit around the Earth (the first ever) to his missions as a shuttle crew member and onboard the ISS.

As mentioned, a diverse set of research experiments will be delivered to the ISS on this mission, along with precious cargo that will assist the onboard crew. Two investigations included in this delivery will take advantage of recent refurbishments made to Solidification Using a Baffle in Sealed Ampoules (SUBSA) hardware, an existing materials science experiment on the ISS launched in 2002.

The SUBSA is a furnace, which operates inside the ISS MicrogravityThe condition of perceived weightlessness created when an object is in free fall, for example when an object is in orbital motion. Microgravity alters many observable phenomena within the physical and life sciences, allowing scientists to study things in ways not possible on Earth. The International Space Station provides access to a persistent microgravity environment. Science Glovebox (MSG) and provides an opportunity to study melt convection in microgravity and visually record the quality of semiconductor crystals—quality that is noticeably improved using a baffle to reduce convection. The updated hardware allows for a wider temperature range, more flexibility in the size of ampoules that can be used, and an improved reading of the solidification point (see this video for more information).

What does this mean for life here on Earth? Semiconductor materials are developed to make smaller, more powerful electronic devices that have potentially unlimited applications. Moreover, the refurbished SUBSA facility is a perfect example of how NASANational Aeronautics and Space Administration and the ISS National Lab, which are managers of the ISS National Lab, are constantly working to evolve the capabilities of the ISS so the laboratory is not only a unique setting for inquiry, but a first-class learning facility.

One of the investigations involving semiconductor materials and among the first to use SUBSA since its refurbishment aims to synthesize unique semiconductor crystals on the ISS. Dr. Aleksandar Ostrogorsky and his team will study the similarities of crystals grown in microgravity to other semiconductor materials. The research team hopes to prove that the unique crystals will have non-toxicity levels akin to other semiconductor materials and that they will grow much faster than typical semiconductor crystals. The results from this experiment have the potential to be applied quickly into radiation monitoring devices.

The second investigation to utilize the updated SUBSA hardware involves the growth of scintillator crystals, which excite when exposed to certain types of radiation. Dr. Alexei Churilov from Radiation Monitoring Devices, Inc., will use this research to help inform the design of  scintillator crystals that can be used in the detection of radiation, primarily for homeland security applications. Additionally, the results from this experiment have the potential to be applied almost immediately to the production of radiation monitoring devices, which range from the detection of harmless sources of radiation to potential smuggled uranium that could be used in nuclear weapons. This research has very broad-based applications, all of which have the capacity to benefit life on Earth.

Given the multitude of projects heading up to the ISS on Orbital ATK CRS-7 and the plethora of investigations already in progress, there is no shortage of fascinating space research. The is just a small glimpse into some of the most recent investigations taking place onboard the ISS National Lab, and there are many more to come!