Space Exploration Technologies (SpaceX) successfully conducted the first “hop” of its Grasshopper vertical takeoff and landing test vehicle (VTVL) on Sept. 21 at the company’s McGregor test site in Texas.

The VTVL is a modified Falcon 9 first stage and forms part of SpaceX’s longer-term ambitions to develop a reusable booster to lower launch costs. The concept will ultimately involve flying the first stage back to the launch site for an autonomous vertical landing.

SpaceX says the “short hop of approximately 6 feet is the first major milestone for Grasshopper, and a critical step toward a reusable first stage.” Powered by the more powerful Merlin 1D engine, the 106-ft. tall vehicle is expected to follow last week’s short hop with a series of progressively more ambitious “mini hops.” Initial flights are expected to reach between 200 ft. and 240 ft. and last less than 1 min. as part of checks of the Merlin’s performance and four-legged landing system.

SpaceX recently said the Grasshopper will be tested on flights up to 1,000 ft., where it will demonstrate its ability to hover. According to information in a draft environmental assessment document published by the FAA in September 2011, the following test flights will climb as high as 11,500 ft. and last up to 160 sec.

Simultaneously, SpaceX is working on the final elements of the official qualification of the Merlin 1D engine, which it aims to complete by mid-November following full-duration mission firing tests at McGregor. The engine has generated 147,000 lb. of thrust during the recent tests, and will make its first flight on a Falcon 9 in March or April 2013.