Cubesat System

About

Overview Satellites have traditionally been relatively large-scale, usually government funded very specialized and focused projects. Satellite electronics packages (i.e., avionics) were typically developed specifically for one specialized mission objective corresponding to the mission of the satellite itself. Further, typical satellite avionics packages were packaged in a customized form factor corresponding to the actual satellite vehicle that also reflected the specialized mission objective.  The individualized development of each satellite vehicle and mission results in much of the engineering and development from one satellite avionics project having very little use in a second satellite avionics project. Thus requiring an entirely new development cycle at much greater cost. By way of example, the avionics of a first satellite would not physically fit within a second satellites airframe even if the mission operations were similar. Thus an entirely new packaging must be custom fit to each satellite.  In more recent history much of space exploration is being undertaken by small organizations such as schools and businesses, rather than as a government-funded project. As a result there is a need for smaller, less costly, more flexible satellite avionics designs that may be re-usable and easily adaptable across a wide range of satellite missions.  Technology Broadly speaking, the present invention fills these needs by providing a smaller, less costly, more flexible satellite avionics designs that is re-usable and easily adaptable across a wide range of satellite missions. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, computer readable media, or a device. Several inventive embodiments of the present invention are described below.  One embodiment provides a satellite system including a chassis, an avionics package included within an upper portion of the chassis. The avionics package includes a main system board, a payload interface board, at least one daughter board and a battery board. The main system board, the payload interface board, the at least one daughter board, and the battery board reside in substantially parallel planes. The payload interface board, the at least one daughter board, and the battery board are coupled to the main system board through one or more stackable connectors.  The main system board can include a long duration timer having a selectable time interval of between about one day and about 12 months. The long duration timer can be configured to interrupt power to at least a portion of the satellite when the long duration timer counts down to zero.  The main system board can include a processor coupled to a non-volatile phase change memory system and a volatile memory system. The non-volatile phase change memory system can include an image of an operating system stored therein in a computer readable media. The processor can include logic stored in a computer readable media for retrieving the operating system image stored in the non-volatile phase change memory system, logic stored in a computer readable media for storing the retrieved operating system image in the volatile memory system, logic stored in a computer readable media for calculating a checksum value of the operating system image stored in the volatile memory system and comparing the calculated the checksum value with a known value, logic stored in a computer readable media for initiating a hard reboot if the calculated the checksum value is not equal to the known value and logic stored in a computer readable media for initiating booting the operating system from the volatile memory system if the calculated the checksum value is equal to the known value.  The main system board can include a removable umbilical system coupled to the main system board by an umbilical connector. The umbilical connector can provide access to operate and debug the avionics system and a payload portion of the satellite. The removable umbilical can include an Ethernet port. The removable umbilical can include a breakout of each one of multiple data lines, multiple control lines and multiple voltage rails in the avionics package and the payload portion of the satellite. The removable umbilical can include rewrite access to the phase change non-volatile memory in the main system board.  The main system board can include a power ground selectively coupled to a first portion of avionics package components through a first low side switch and a solar ground coupled to a battery ground during flight through a second low side switch.  Another embodiment provides a method of resetting a satellite including selecting an interval for a long duration timer of between about one day and about 12 months, allowing the long duration timer to count down to zero, interrupting power to at least a portion of the satellite and rebooting the at least a portion of the satellite.  Interrupting power to at least the portion of the satellite can include interrupting a battery ground to at least the portion of the satellite. Interrupting power to at least the portion of the satellite includes interrupting power to at least the portion of the satellite for less than about 1.0 seconds.  Yet another embodiment provides a method of rebooting a satellite including retrieving an operating system image stored in a non-volatile phase change memory system, storing the retrieved operating system image in the volatile memory system, calculating a checksum value of the operating system image stored in the volatile memory system, comparing the calculated the checksum value with a known value, initiating a hard reboot if the calculated the checksum value is not equal to the known value and booting the operating system from the volatile memory system if the calculated the checksum value is equal to the known value.