Functionality

The hardware must support the various demands of increasing levels of automation by providing basic functionality including:

1. Sufficient processing ability for increased software loads.
2. Interrupt support and hardware timers, necessary for real-time operating system support.
3. Sufficient memory, processing power, and system resources to support mission goals.
4. Adequate communications bandwidth to support the transfer of data and commands between the ground system and flight system.
5. Non-volatile memory for storage of code updates and system configuration parameters.
6. Sufficient I/O capability, including both adequate transfer rate and numbers and types of channels.

In addition, to provide the performance that widely varying mission requirements demand, the hardware may support scalability by incorporating additional features including:

1. Direct memory access (DMA) support to allow high speed transfers between system peripherals and memory.
2. Use of appropriate standards such as VMEbus to allow easy incorporation of additional interfaces and multi-processing capability, which can also allow redundancy to protect against a single processor failure.
3. Support for increasingly compact, inexpensive, and power-thrifty memory elements such as solid state disks and standards such as PCMCIA to allow a system to contain far more data storage capability than was previously possible.
4. Support for reusability and reconfigurability; an example being Field Programmable Gate Arrays (FPGA's) used as I/O interfaces.
5. Network support, so that if required, communication between multiple computers in the same spacecraft or within a constellation may use commercial network protocol standards such as TCP/IP.

By providing the ability to reuse existing hardware designs merely by upgrading to the current technology, less time is spent developing and maintaining mission operations software specific to each hardware configuration, thus maximizing the benefits of software reuse.