On Friday, September 21, 2012 SpaceX’s Grasshopper vertical takeoff and landing test vehicle (VTVL) took its first test flight hop from the company’s rocket testing facility in McGregor, Texas. The short hop of approximately 6 feet is the first major milestone for Grasshopper, and a critical step toward a reusable first stage for SpaceX’s proven Falcon 9 rocket. As seen in the video, Grasshopper consists of a Falcon 9 first stage, a Merlin-1D engine, four steel landing legs, and a steel support structure. SpaceX is working to develop vehicles that are fully and rapidly reusable, a key element to radically reducing cost and increasing the efficiency of spaceflight. Testing of Grasshopper continues, with the next big milestone — a hover at roughly 100 feet — expected in the next several months.
SpaceX technicians added four steel landing legs and a support structure to a qualified Falcon 9 rocket first stage. The Grasshopper program is the first step in achieving SpaceX’s goal of developing a reusable booster, which would require the rocket’s first stage to fly back to a landing pad at or near the launch site.
Here is a video of the goal of fully reusable rockets.
“The payload penalty for full and fast reusability versus an expendable version is roughly 40 percent,” Musk says. “[But] propellant cost is less than 0.4 percent of the total flight cost. Even taking into account the payload reduction for reusability, the improvement is therefore theoretically over a hundred times.”
A hundred times is an incredible gain. It would drop cost for Musk’s Falcon Heavy rocket—a scaled-up version of the Falcon 9 that’s currently rated at $1000 per pound to orbit—to just $10. “That, however, requires a very high flight rate, just like aircraft,” Musk says. “At a low flight rate, the improvement is still probably around 50 percent. For Falcon Heavy, that would mean a price per pound to orbit of less than $500.” Falcon Heavy is particularly amenable to reuse of the first stage—the two outer cores in particular, because they separate at a much lower velocity than the center one, being dropped off early in the flight.