Like that headline? It's factually true, though a little overblown. Yet somehow, when you read it, doesn't it sound like someone is actually trying to make it look like NASA is covering something up?
I wrote it that way on purpose, to show you how some antiscientists will no doubt cast a NASA press release saying that comet 73P Schwassmann-Wachmann will not hit the Earth. I've already written about this (here and here and here), and I find it irritating that NASA feels the need to debunk it as well. They have better things to do.
I, of course, have plenty of time, and nothing better to do.
NASA doesn't have any official debunking of the Face on Mars, or the Moon hoax, because they feel that it's beneath NASA's dignity to even acknowledge such crap. I see their point, though I also think that once some piece of nonsense gets widely spread enough, there should be resources to fight it. However, I don't think NASA should be in that game, for two reasons.
One is that NASA really doesn't have the time or money to do it. Debunking effectively is not all that easy, and it takes time to do it right. When an organization like NASA is defunding projects left and right, it's probably best they not waste time taking on the likes of Hoagland or Sibrel.
But the other reason is more subtle. As soon as NASA jumps into the fray, the antiscientists go nuts (well, more nuts). They scream, "I must be on to to something, because now even NASA feels like they have to deny it!". I've seen that happen many, many times. The irony of it (well, one of many ironies) is that if NASA ignores them, they scream "I'm being suppressed!" or "Why is NASA silent about this?". They win either way.
Given all that, I think it's best that NASA stay out of the debunking business. I think they should be helpful (supply images and such, and answer questions), but their general attitude now is the correct one: don't simply deny something outright (it makes you look guilty), but don't give the nutty ideas credence either. It's a tightrope act, I'll admit, but so far they're doing it pretty well.