There's another good related article linked at the bottom of that page:

Smoking Gun Proof From NASA Software Engineers That Mars Rovers Are On Earth — Not On Mars

a lengthy anonymous essay posted on an astrophysicists blog written by a software engineer who had worked for NASA — and during a routine trouble-shooting job with the rover, discovered a “backdoor” in the Mars rover’s software that allowed NASA to receive thumbnail images from the rovers “on Mars” allegedly in real time — no time delay, but because of the immense distance between Earth and Mars — this would be a scientific impossibility — as radio transmission faster than the speed of light is an impossibility.

Of course, the software engineer truly believed that the rovers were on Mars — as do most NASA scientists — so the only explanation he could come up with to explain how NASA was receiving these thumbnails in real time was to speculate that NASA had developed some “secret” technology that allowed them to receive these images in real time while failing to apply Occam’s Razor and completely ignoring the simplest — and obvious — explanation that they rovers were on Earth, not Mars.

If you have the time to read the full article written by the astrophysicist, I highly recommend it despite it's semi-novella length. I came across it a couple of years ago and it's a fascinating read. It's a great example of the compartmentalization that prevents even people working on these programs from knowing the whole truth of what they are working on.