Re:Accessibility (Score 2, Informative)

Properly written AJAX isn't any less accessible than a plain old HTML form. Just make sure your AJAX events are triggered by actions that would normally result in a regular HTTP request (like clicking an anchor or submit button on a form). This way, there's nothing lost if Javascript is off. Everything else can follow the 508 guidelines just as strictly as a well-designed static page. So go ahead and pitch that AJAX app to NASA.