SpaceX is experimenting with building a completely and rapidly reusable rocket called Grasshopper. There have been five tests so far, each to a higher altitude, and the most recent test was a very large leap above the previous. Here’s a quick graph:
It’s very tempting to draw out an extrapolated exponential curve into the coming months and years. What faults could hold the altitudes down in the short term? Perhaps a large slowdown after reaching LEO, or even for middle-atmosphere tests? Are they on track to land robots on Mars by ~2018? I think they are. I imagine a future Dragon packed with instruments, sensors, food, water and fuel sitting on Mars in 2020, waiting for a human mission in the early 2020s.
Of course, anyone who lands on Mars will have to be careful of planetary-scale duststorms. I’ll try to scale pressureNET out to Mars to help out.