The National Aeronautics and Space Administration (NASA) is at the forefront of technological development for use in space travel and exploration. However, many of the innovations that are developed by, or in collaboration with, NASA are actually used a lot closer to home as well – we take a look at some of NASA's technologies which have really taken-off here on Earth.
Aerogels: outer space to outerwear
Traditionally, NASA has used hard aeroshells for delivering payloads, such as rovers, to other planets. These generate drag to slow the payloads in descent, while also acting as heat shields for atmospheric re-entry.
In order to successfully land larger instruments, and potentially humans, on planets such as Mars, NASA has been exploring a new approach: the hypersonic inflatable aerodynamic decelerator (HIAD). Unlike fixed aeroshells, the HIAD can be folded up and stored in the spacecraft during flight before being inflated into an umbrella-shaped decelerator to control descent. In order to meet the stringent weight constraints of space travel, an incredibly lightweight material is needed.
For this, NASA turned to aerogels. Aerogels are highly porous, low density solids and traditional silica aerogels are one of the most thermally insulating materials known to man on account of the multitude of nanometre scale pores. However, silica aerogels are very fragile. Even when incorporated into a composite material, folding a silica aerogel causes significant dust shedding which makes the material unsuitable for use in HIADs.
NASA's solution was to create a completely new type of aerogel made entirely of non-silica polymers, in particular a cross-linked polyimide network (as described, for example, in US Patent No. 9109088). Polyimide aerogels are much stronger than silica aerogels, and can be made into thin, flexible films. Careful control of the synthetic method and selection of cross-linking agents allowed NASA to identify specific formulations with optimised moisture resistance, mechanical properties and stability. It is expected that HIADs exploiting these new polyimide aerogels will be widely adopted in the next era of NASA's space exploration.
Meanwhile, NASA has licensed this patented technology to companies in many different fields including Lukla Inc. (trading as Oros), who make extreme-weather outdoor wear. They have developed highly insulating clothing in which NASA's polyimide aerogel is saturated into the textile (see US Patent No. 10729194). Since the polyimide aerogel does not shed dust like traditional silica aerogels, there is no need for an encapsulation layer to contain the aerogel. This allows the jackets to be lighter and more flexible, while still benefitting from the outstanding thermal insulation properties of these next-generation aerogels.
Chemochromic hydrogen detection tape
In recent times, NASA has relied on liquid hydrogen as the fuel for the upper stages of its rockets. However, although hydrogen is an incredibly efficient fuel, it is also highly flammable. It is therefore crucial that any leaks in the miles of pipeline which are used to transport liquid hydrogen around a launch site are identified quickly.
During the 1990's, the best leak detection instruments were electrochemical and combustible gas sensors. Unfortunately, such sensors could only identify the general area of a leak, and it was then often difficult and time-consuming to pinpoint the exact location of the escaping hydrogen gas.
In pursuit of a more accurate and expedient detection method, NASA entered into a collaboration with the University of Central Florida (UCF) to develop a visual hydrogen detector. The starting point was a powder of palladium oxide and titanium oxide which changes colour on exposure to hydrogen. However, the colour change was slow and not easily identifiable. Undeterred, UCF worked to modify the original powder to produce a pigment which gave a clear colour change, from beige to black, within three minutes of hydrogen exposure (see US Patent No. 8048384).
NASA incorporated UCF's pigment into a tape which was stable at extremely cold temperatures (the hydrogen pipes have to be kept at -250oC to keep the hydrogen liquid) by combining the pigment with an aerogel and supporting the composite within a polymer matrix (as described in US Patent No. 8293178). From 2007 all the way through to 2014 and the last launch of Space Shuttle Endeavour, the tape was successfully used to identify potentially lethal hydrogen leaks.
NASA's patents for this technology were subsequently licensed to UCF, who then licensed the whole portfolio to HySense Technology for commercialisation. Now acquired by Nitto, HySense Technology's chemochromic tape is widely used in oil refineries, steel manufacturing and chemical plants to detect hazardous hydrogen leaks. The ease of application, resistance to harsh environments and high sensitivity make it an incredibly successful and versatile product.
NASA's investment into out-of-this-world innovation and their pursuit of patent protection has allowed for a wide range of licencing opportunities, enabling forward-thinking companies to incorporate NASA's technologies into useful products which can be found right on our doorsteps.
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