> Memory today is cheap (even if we're talking about the radiation-hardened stuff, for "space mission" levels of cheap) New Horizons was launched in January 20

> Memory today is cheap (even if we're talking about the radiation-hardened stuff, for "space mission" levels of cheap) New Horizons was launched in January 2006, but I suspect you know this and you're just being dramatic to make a point. :) The problem with "cheap" as a metric whose context is solely monetary is that it's ignoring maaku's fundamental argument: More storage is more weight; more transmitter capability is more weight. So it's not just the cost of the storage you're looking at but also the cost to get that into space. Launches are not cheap, and you have to account for every bit of spacecraft weight which leads to design tradeoffs. Sometimes you can have one or the other--not both. Interestingly, the New Horizons program has its roots dating back to the 1990s, at least according to Wikipedia, with cancellations due to projected costs exceeding levels NASA was willing to fund. But this is par for the course when dealing with long-term, long-distance missions. Everyone has an argument about what to put on board, but there's neither budget nor space to accommodate them all (sadly).