The slow data rates available for broadcasting images back to Earth and the team's familiarity with that family of sensors played a part, says [Ravine], but the biggest factor was the specifications being fixed as far back as 2004. Multi-shot panoramas will see the cameras deliver high-res images, he explains, but not the 3D movies Hollywood director James Cameron had wanted.

'There's a popular belief that projects like this are going to be very advanced but there are things that mitigate against that. These designs were proposed in 2004, and you don't get to propose one specification and then go off and develop something else. 2MP with 8GB of flash [memory] didn't sound too bad in 2004. But it doesn't compare well to what you get in an iPhone today.'