If an environmentally friendly group of alien programmers had written Angry Birds Space, it might have turned out much like Solar Flux HD ($3.99). Instead of destroying pig domiciles in the far reaches of the universe, you need to heal ailing suns through clever manipulation of your spacecraft.
The game is 226MB in size, so you might want to grab it through iTunes or Wi-Fi. When you start it up, it walks you through the basic tutorial levels to teach you how to control the ship, collect plasma fragments, and use the various gravity effects to score on each level. The game ran pretty well, though it seemed to take longer and longer to load as I progressed.
The point of the game is to heal the stars in each level before your shield is depleted and your ship burns up from exposure (or runs out of fuel). The dynamics are much like you would expect in the vacuum of space, with the exception that the ship enters planetary orbit automatically when getting close to a gravity well. Planets, stars, and other space objects are rendered in attractive detail, and you need to become skilled at maneuvering in a vacuum and around large planetary bodies to capture plasma quickly.
To control the nut-shaped ship, you can use thrusters (thrust direction and duration is controlled by screen taps on the side to which you wish to apply thrust); or slingshot around a planet, trying to maneuver close to the plasma fragments sprinkled around the area (which get sucked into your ship.) Once collected, they need to be launched into the sun (the healing needed to complete each level.)
When the plasma strikes the suns, a flare occurs, which may apply a force vector on a tangent (that's a fancy way of saying the ship could go flying off at an angle). Precise timing is required to avoid being driven into another object like an asteroid, or out of the game playing area (though you will eventually be bounced back in). Keep an eye on shield level, fuel level (indicated in the corner HUDs), and strategically plan your routes to quickly grab the plasma. Collect all the fragments and launch them (by tapping a sun) before ship burnout in order to progress.
Solar Flux HD is a solid visual experience, and on a par with other decent physics puzzlers. I do have a few enhancement ideas. It would be cool to include missions that require sophisticated ship control (i.e. to enter a stable planetary orbit or snag power ups). The old 70s game, Lunar Lander, is an example (really one of the coolest all-time physics puzzlers). It would also be cool to introduce extra challenges, like the threat of a Sun going supernova—suns swell, get hotter, deplete shields faster, and explode. Of course maybe these features are included in higher levels which I haven't yet played. It is a bit pricey, but if stabilizing the universe is your cup of tea, grab it in iTunes.
Interesting game concept
Slow loading as you advance