Here's the video of the most recent SpaceX Grasshopper flight:<p><a href="http://www.youtube.com/watch?feature=player_embedded&v=2Ivr6JF1K-8" rel="nofollow">http://www.youtube.com/watch?feature=player_embedded&v=2...</a><p>(via: <a href="http://forum.nasaspaceflight.com/index.php?topic=30708.msg1024337#msg1024337" rel="nofollow">http://forum.nasaspaceflight.com/index.php?topic=30708.msg10...</a> . May not be available in some areas due to music licensing.)
It doesn't have an aerospike engine. The first leg of the journey is always the hardest at sea level so if they can use less fuel there, it will be easier on the rest of the trip. Aerospikes are more efficient at lower altitudes and offer a greater throttle range (since each burner can be independently controlled).<p>Whether this is a multi stage or single stage, an aerospike is something they need to look into. It's been overlooked by the majority of manufacturers and enthusiasts, which is a shame because, even though the engineering may be difficult, there is still a lot of research behind it as well.
This impressive video from Armadillo is three years old. I wonder what they are up to now.<p><a href="http://www.youtube.com/watch?v=9u0qlIoSSkQ" rel="nofollow">http://www.youtube.com/watch?v=9u0qlIoSSkQ</a>