Testing the world's blackest material in orbit
A cutting edge light retardant coating designed to reduce the interference to the delicate optical equipment mounted on space probes is being put through its paces aboard the Kent Ridge 1 satellite, which launched into low-Earth orbit (LEO) in Dec. 2015. Known as Vantablack S-VIS, it is hoped that the high performance and versatility of the material will allow for the design of lighter, more compact satellite hardware.
Star trackers are a vital piece of equipment for any orbital or deep space exploration mission hoping to accurately navigate the relative void beyond Earth's protective shell. The equipment works by accurately determining a spacecraft's position based on (as the name would suggest) the visible star field.
Kent Ridge 1 is a compact, 78 kg (171 lb) microsatellite designed primarily to facilitate disaster monitoring and relief throughout Asia. This will be achieved by providing detailed Earth imagery of affected regions from LEO via two onboard hyper-spectral imaging systems, and one high res video camera.
The spacecraft will rely on a series of reaction wheels as well as four star trackers mounted on the top and bottom of the satellite. The more accurate the star trackers, the less the probe will need to rely on internal gyroscopes to fix its position in space, which can lead to a drift in the satellite's position over time.
Instruments aboard satellites operating in LEO must contend with interference in the form of light emitted and reflected from the Sun and Moon, which has the potential to confuse a star tracker's sensors. Light bouncing around the interior of a system can have a similar effect in throwing off the equipment.
To reduce the disruption, the interior and baffles of the instruments are coated in light absorbing materials. Traditionally, black paint was employed as the coating of choice.
At short notice, Berlin Space Technology (BST), one of the manufacturers of the satellite, decided to take a more innovative approach, opting to use ultra-black Vantablack to coat the 3D-printed baffles that protect Kent Ridge 1's navigational instruments.
According to BST, the Vantablack coating
is around 17 times less reflective than the super-black paint used to guard the delicate optics of the Hubble Space Telescope from stray light interference.
The carbon nanotube matrix element of ultra-black Vantablack grants the material a reflectance value of only 0.2 percent, spanning a wide range of wavelengths. Furthermore, the coating can be applied to engineering-grade polymers and composite materials via what is essentially a "spray paint" application process, making the material supremely versatile.
The video below shows the Vantablack coating in action.
Source: Surrey NanoSystems