Mission to Mars is a movie that has a lot of potential, but most of it is wasted because of its directness (i.e., showing us what we're not supposed to see) and its pacing.
The plot borrows unabashedly from 2001: A Space Odyssey and a little bit from Contact, and unfortunately, unlike the former film by Stanley Kubrick, it is not self-indulgent enough. The first humans land on Mars and (after losing three of the crew) discover a structure resembling a face buried in the sand, emanating a radio signal. After decoding the signal to be genetic information, and seeing a few base pairs of said information, the humans on the ship realise that it's very similar to the approximately 3 billion bases that comprise the human genome. To get inside the structure, they must reply in kind signifying that they understand the code.
And they do. And they discover strange and wondrous things, including an alien race whose genetic make up is more similar to us than a chimpanzee's, but yet appear so different (almost as though they were generated using computers). But these aliens can cry and that's all that matters. As the (tearful) alien explains how they seeded earth with the first life forms as Mars was destructing, we are presented with a linear depiction of the evolution of life on earth (i.e., from single-celled life forms to fish to amphibians to something on four legs to humans), which makes for an interesting (albeit erroneous) history lesson.
Readers will note that I don't say much about the characters (deliberately). That's because they're so devoid of any personality that it isn't worth mentioning them. The actors who play the characters have a thankless job and don't do well at all. Forget the science for a minute; let's assume Mission to Mars is a human interest story. Even in that regard, it fails miserably, delving into cliches and contrived situations.
For example, the Van Halen tune is nice, but it is really incongruous, as are a bunch of other scenes that attempt to add tension to a film that isn't about tension. These include two scenes involving oxygen deprivation and the wanton deaths of the three crew members (surely an intelligent life form would have the ability to make devices that could recognise humans, its creations). Mission to Mars does have some cool visuals and effects (especially the sand storm creature), and they did get the design of the special flag right. If you're really bored, it's worth the matinee fare, but otherwise I'd skip it.