It's definitely an interesting premise, but the shifting tenses (no offense, but it feels like you're fleshing out an outline and not being too careful about this) sometimes make it less enjoyable a read than it could be. The ending leaves lots of potential for sequels or further chapters; though how Harry & Hermione get involved with the Stargate effort is an open questions (given Harry's 'chaos attractor' nature, you know some event would link him there).
Author's response
I left it open in a way that people can continue with it in many different directions. And I know my grammer sucks :p