What would be gained...?
@Aimee
"What would be gained by a nation attacking a spacecraft going to Mars?"
Well, just as an exercise, let us construct a reasonably plausible conspiracy theory...
1 - The Americans have just recently built a small aerodynamic orbital craft. This has the capability of being launched in one orbit, then changing its orbit to another to match a target, then returning back again - all in a portion of an orbit while the target is out of view of its owners. So they have the means to undetectably deliver a short-range damaging high energy pulse to an orbiting target should they want to...
2 - NASA funds are being wound down, and the US are going to rely on Russian rocketry for launches for a while. A lot of people won't like this. In particular, there were a lot of 'spook' funds hidden in NASA budgets - these will be at risk. So there would be an interest in making Russian space technology (which, up to now, has looked superb) look unreliable. And, surprise, surprise, Russian space technology HAS suddenly started to look unreliable.
3 - No one wants to interfere with manned missions. The fallout and inquiries resulting from a failed manned mission would be uncontrollable. But the odd scientific or commercial package - there would be far less investigation of those. And a Mars mission, which presumably has the best Russian reliability built in - well, if that went wrong it would be a very good reason to keep NASA skills operational....