The RocketCam doesn't look like anything special. But don't let the primitive exterior fool you -- this gadget is rugged. It can endure extreme speeds, vibration and temperatures.
Beneath its clunky exterior, the basic camera is about 2.8 ounces (about 80 grams) and four inches (10 centimeters) long [source: Space Show, Fine]. RocketCams use professional-grade Sony miniature color video cameras (in the past, the XC-999 model). But you can't just take one of these cameras and strap it to a rocket. To make the camera ultra durable, Ecliptic Enterprises Corporation takes the camera apart and puts it back together again. During this process, it ruggedizes (or strengthens) the camera, bolting it to a platform with added features that make it tough enough to withstand extreme environments. The camera's casing has an aerodynamic design, and a layer of insulation foam on its surface helps to protect it from extreme temperatures.
The Ecliptic engineers also add technical features. For instance, every RocketCam that is built to take a ride on the external tank of a shuttle has a radio transmitter and antenna to send the video information down to the ground from space using electromagnetic radio waves. This allows the information to be sent quickly to multiple receivers. The camera may also incorporate various battery sizes or power support boards and other adaptable features, depending on the use.
RocketCams may be either analog or digital. These terms simply refer to how the visual data is recorded and reproduced. In analog recording, an older method, the device records information in continuous variations of waves. Digital technology doesn't use waves, but rather records information in numbers, such as in 1s and 0s. Digital versions of the RocketCam are more sophisticated with added features, such as "store-and-forward" viewing, which allows those on board to review video, similar to how a TiVo works. It also enables improved radio frequency (RF) bandwidth, which means it uses the available bandwidth more efficiently.
Digital models take in a large amount of information in order to capture things like payload separation and to aid in failure investigations. To accommodate that, the digital RocketCam compresses this information to send it over electromagnetic radio waves down to Earth. (Although digital technology doesn't use electromagnetic waves to record information, it can use those waves to send information it as recorded elsewhere.) Compression of digital information involves finding common repeated patterns and shortening them, as you'll learn in How File Compression Works. To carry out the process, the engineers incorporate a compressor which uses a Digital Signal Processor chip to format the information.
Although they are most known for their positions on the outside of a launching vehicle, some RocketCams offer even more information about a space launch by recording the interior of a ship. SpaceShipOne, the first privately funded manned ship to go to space, used two interior RocketCams for the cockpit in addition to cameras on the exterior. These internal cameras don't require protective casing.
When used on space shuttles, NASA mounts RocketCams to the exterior fuel tank and on the two solid rocket boosters. These structures release from the shuttle after takeoff, so the camera only hitches a ride temporarily on a shuttle. But by this time, the vital information has already traveled to the ground.
At a mere 5 pounds (about 2,267 grams), this camera serves a lot of purposes [source: Space Show]. Read on to find out why it's so important.