Build a DIY Satellite: CubeSat 1U Case

Build a DIY Satellite: CubeSat 1U Case

CubeSat is a class of satellites based on a 1U format with the dimensions 10 cm × 10 cm × 10 cm (1 litre volume), and mass 1.33 kg. It is usually available as a kit consisting of commercial off the shelf (COTS) components and hand assembled. Due to their small size and weight, their launch costs anywhere from £65,000 to £80,000, and the launcher is usually the SS-18 missile, which is capable of carrying it into low earth orbit (LEO) at an altitude of approximately 680 km. The vendors of kit components are Pumpkin Inc and “CubeSatShop”, who provides a complete solution in kit form at low costs.

These satellites usually draw power from batteries, and a small solar panel attached to the sides of the cube continuously recharges them. Currently they do not have a propulsion system; however, one good contender is an ion engine, which provides the necessary thrust to orient the cube.

CubeSats are scalable along one axis, hence it is also possible to have them in a 2U format (20 cm × 10 cm × 10 cm), and 3U format (30 cm × 10 cm × 10 cm). The concept of standardising size and weight is so that rocket designers can better anticipate the payload requirements. It is currently possible to buy a “ride” for these satellites; often a large project utilising a larger rocket may have a number of available “free seats”. The Indian rocket PSLV is usually able to carry these payloads at extremely low costs.

Typically built as a kit using COTS software and hardware, the satellites cost very little compared to their conventional counterparts. Standardisation results in lower research costs and firms such as Pumpkin Inc are providing ready-made kits and complete hardware and software solution packages that have been tried and tested in space, thus saving huge development costs.

Applications

New developments in advanced integrated circuit design mean that semiconductor technology can occupy very small volume, require minimal power, and yet provide a staggering amount of processing capability. This allows CubeSats to carry large numbers of instruments and sensors, which would usually cost millions using conventional satellite technology.

Conventional Earth observation satellites typically weigh tonnes and cost anywhere between £50 million to 400 million, and that is not including the cost of the ground crew, operations control, and infrastructure set-up and maintenance. The stakes are often soaring high, and if the whole project fails because of a rocket failure then you have no choice but to watch billions of pounds worth of hardware fall back to the ground. It is therefore very easy to realise that these small satellites carry very small risks but provide huge pay-offs.

History

The first satellite in 1957 was “the people’s satellite” because anybody could tune into its 'beep' signal using a home radio. Sputnik was a 23-inch diameter perfect sphere that weighed 83 kg. It had two independent 1 W transmitters. Compared with today's technology, the printed circuit boards were crude with large Russian transistors and resistors. Nevertheless, it worked wonderfully.

The first CubeSat project began in 1999, when two American scientists, Bob Twiggs of Stanford University, and the aerospace engineering professor Jordi Puig-Suari of California Polytechnic University defined the standards when they built their own satellite. In many ways this was the first true peoples satellite, because today people from all over the world are able to build a similar design and launch it into space at minimal cost.

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