In NASA's language, a nanosatellite-class system is a small spacecraft, but it is not a nanotechnology-based device. In fact, its new 'Mini AERCam' robotic cameras are small, free flying vehicles capable of performing inspection and viewing missions in space. But these spherical-shaped cameras have a diameter of 7.5 inches and weigh about 10 pounds. These cameras are designed to help astronauts and ground crews see outside the spacecraft during a mission. During human space flights, like the ones of the International Space Station (ISS), their use will suppress the need for astronauts to walk in space. And these cameras, tested on the ground today, should be soon deployed in space to watch human-based missions in space. Read more...
Here is the introduction of the NASA's news release about these small robotic cameras.
Big things can come in small packages, and engineers at NASA's Johnson Space Center are making progress on a tiny spacecraft that holds major promise for future exploration.
Work on the volleyball-sized Miniature Autonomous Extravehicular Robotic Camera (Mini AERCam) moved forward with successful initial tests on its docking system. The Mini AERCam is designed to help astronauts and ground crews see outside the spacecraft during a mission. During ground-based testing, the device was able to work with the docking system that serves as an exterior home base for housing and refueling the nanosatellite.
So this Mini AERCam is 'volleyball-sized,' quite bigger than nanotechnology-based devices according to the 'official' definition of nanotechnology -- less than 100 nanometers.
Below is a diagram showing the Mini AERCam external features (Credit: NASA).
Two cameras are aligned with the +X direction of the vehicle. One camera provides NTSC-quality color video, and the other camera can be used for high-resolution still images, when selected. A third color video camera is positioned in the +Y direction for an orthogonal view.
And here is an exploded view of the Mini AERCam (Credit: NASA).
The vehicle is designed with a central ring that houses the power and propulsion system. The batteries are lithium-ion and provide six hours of operational time. The propulsion system is designed for cold-gas xenon, which packs more densely than nitrogen, but is compatible with low-cost nitrogen in the current ground test configuration. Attitude and position control are achieved with the use of twelve thrusters, distributed across four thruster pods around the central ring. The batteries are rechargeable and a port is provided for refueling.
Now, let's go back to the NASA's news release to discover how these cameras can be deployed in space and docked outside of a bigger spacecraft.
Mini AERCam could be deployed and retrieved many times during a single space mission, with the use of a hangar-based docking system located on the exterior of the vehicle. The free-flyer portion of the docking system includes a vision-based system for autonomous navigation and an electromagnetic capture capability.
For human spaceflights, automatic deployment and docking eliminates the need for astronauts to perform a spacewalk to release and retrieve the free flyer. For robotic missions, external basing is essential. The docking system provides a protective base during periods it is not needed for mission operations.
For even more information, here are two pointers to the Mini AERCam home site and to a technical overview (PDF format, 4 pages, 589 KB). The pictures above were extracted fom this document.
Sources: NASA news release, June 15, 2005; and other NASA sites
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