What does it promise? The biggest challenge with this content-filled app is that is includes no explanation of what it is or what it's supposed to do. If you play around with it, you realize that it gives you access to all things NASA, including information about space, access to NASA TV (a collection of videos) and access to other NASA products and feeds.
Does it deliver? The app is very data rich, and users can learn quite a few basic facts about outer space. In general, if you click on something (say a picture of Saturn), you'll be rewarded with some interesting information.
Can I use it in my classroom? You can show a number of videos by connecting to a TV, and the NASA HD app provides a wealth of great information for student use. The app definitely could keep children of varying ages (kindergarten through high school) engaged, as it features many useful items, including a link to NASA's Twitter feed.
All apps can be found in the iPad apps store under education.