Here's that information that James and I came up with regarding the CPU for this satellite project. Essentially it looks like the same type (MSP430) of microcontroller that the Taylor project used would be a good choice for our project with a few modifications. TI has a great chip selection interface shown here: http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?familyId=911§ionId=95&tabId=1527&family=mcu I went through the list of stuff and picked one that I thought had the right characteristics, and is carried by Arrow: http://app.arrownac.com/aws/pg_webc/0,1086,,00.html?application=SEARCH&event=1009&search_token=MSP430F156IPM&search_criteria=match_begins_with&match_in_stock_only=NO&=&rows_to_display=10&limit=10&full_domain_name=app.arrownac.com&super_neda=&start_index=0&search_type=click_through The Wikipedia page for this series of processors is fairly well done: http://en.wikipedia.org/wiki/TI_MSP430 Speed There are several different series with different speeds: 8, 16, 20, 25 MHz. I think it makes sense to go with the 8 MHz model for our needs. ADC As for ADC functionality, it looks like they have both 10 bit and 12 bit successive approximation converters. I believe they are internally multiplexed so that 8 different measurements can be made with the same converter. DAC These chips have an on-board DAC option, and it looks like they come in pairs. Surprisingly, they are listed as 12 bit converters, which is nice. Programming It looks like TI has their own compiler suite, although the free version will only allow you to write up to 16 KB of code. I believe C is a universal language for microcontroller coding, but have not verified that the compiler supports it. SPA As for SPA connectivity, many of the available chips have I2C busses available, with a maximum clock speed of 100 – 400 KHz. Both TI chips and the SPA documentation are little endian, which is a good match. SPA has a data limitation of 253 bytes in a reply message. Memory These chips have a huge assortment of available flash memory, some absurdly large. I believe that the free compiler limit of 16KB will be sufficient for a project of this scale. Amounts of RAM are generally pretty small, ranging from 256 bytes to 2KB for the 8 MHz chip. It would be nice to have some kind of information about how much data we are generating and storing. Prototyping It looks like TI sells several different evaluation boards for around $100. It looks like these generally come with more or different features than we are looking at, and it may take some work to find one that contains the DACs, ADC, and IIC components we will be using.