Electronically de-spun phased array antenna for spinning spacecraft

A spinning spacecraft typically uses an S-band omnidirectional antenna to maintain a data link to Earth and thus does not need an expensive attitude control system. However, a higher downlink data rate and/or cost savings might be obtained by using a transmit antenna with gain in the less occupied X-band. A linear phased army of microstrip radiators can achieve significant gain and some steering while having a lightweight package on board the spacecraft. Arranging the flat panels of such an array on the sides of a regular polygon, around the spacecraft spin axis, allows the beam from each pair of adjacent panels to overlap. Each pair of successive panels, excited sequentially at the spin rate of the spacecraft, can point the radiated beam toward Earth continuously. Greater transmit antenna gain on board the spacecraft has several possible benefits including: (1) increased downlink data rate, (2) reduced transmit power, (3) access to downlink data on Earth by commercial dish receivers rather than the expensive Deep Space Network (DSN). As demand and availability increases, cost of the required X-band components and equipment should decrease.