Kimbo-IV

Highlights:  First ever flight of composite LOX tank.

Click here to view more pictures of the Kimbo-IV launch.

More details below.

The Kimbo-IV flight team successfully launched the Kimbo-IV vehicle on Saturday, 3 June 2000 at the Reaction Research Society's Mojave Test Area. To the best of our knowledge, this flight represented a technical milestone in the history of rocketry- it was the first time that a composite LOX tank has ever been flown. Such technology (provided by Microcosm) has the potential to reduce the weight of next-generation launch vehicles.

Most of the team arrived at the site on Friday and preparations went according to plan up through Saturday morning. The weather was sunny and warm with minimal ground-level winds. We had the vehicle stacked vertically on Kevin Baxter's launch rail and Chris Thompson had finished the alcohol loading by 10:00 a.m. when we ran into the one big potential show-stopper of the day. As Mark Holthaus powered up the on-board electronics, the ordnance charge in the nosecone deployment mortar tube fired (most likely the result of a sneak ground loop), "successfully" deploying the nosecone and associated parachutes and causing a high level of excitement for Mark and the crew near the base of the vehicle. The shock damaged the mortar tube and gave the rest of the vehicle a good jolt.

Fortunately, John Engberg, Mike Novratil and Mark were able to repair the recovery system and repack the parachutes in little over 1.5 hours. We made a team decision to proceed with the launch using only the backup timer for the ordnance initiation commands. Alcohol loading got started again at 11:50 a.m., with ground winds still minimal but the temperature now pushing up towards 100 F. Mike and Chris took turns tracking down several pneumatic leaks (possibly induced by the nosecone deployment shock), while several folks, most noticeably K.Mark Caviezel, had to sprint back and forth at literally the last minute to the tracking tower to work around some comm issues. Sometime around 12:30 we finally entered the automated countdown sequence and everything proceeded nominally. Mark's igniter lit up on the first try and Steve Molenda's Main Valve assembly opened up 2 seconds after reception of the break wire burn-thru.

The vehicle took several seconds to fly up the 57-ft launch rail. Shortly after leaving the rail, the Kimbo-IV then pitched over sharply in the downrange direction. The assessment of many observers is that the vehicle (which had a large margin of static aerodynamic stability) encounted a wind shear and weathervaned. The resulting trajectory was less than optimal for the recovery system and in any event, the nosecone remained attached to the vehicle through the entire flight, which lasted approximately 37 seconds. At that point, the vehicle made a nose-first impact in the lake bed, 2.9 miles away. Although I have not yet seen any, I have heard that a number of observers captured great videos of the entire flight (Steve Bartlett has a good one of the vehicle flying up the rail).

The recovery team then navigated through the desert and across the lake bed and after several hours of digging through the thick clay soil, managed to recover a decent fraction of the vehicle. The winch on Kent Grasso's Rover was key in pulling out the engine section, complete with the entire engine assembly and all four fins still attached. Despite the tremendous shock, there is still a possibility that some of the hardware, specifically the injector elements, may be re-useable. Steve subsequently delivered the recovered gear to my garage and we will take a closer look tomorrow (Tuesday) evening. Unfortunately, because we were pre-occupied with finding and analyzing vehicle components, we missed out on Eric Claypool's successful static fire of his 640 lbf engine.

The loss of the K-IV vehicle was obviously disappointing, not in small part because of the tremendous effort and contributions that Chris, Mark, John E., Steve, Mike, Kevin, K.Mark, Tom, Steve B. and the folks at Microcosm and numerous others have made. However, that is part of the risk in this kind of hobby and we have all learned a great deal in developing and flying the Kimbo-III/IV. Fortunately, the Kimbo team has a number of new opportunities that are definitely now within our capabilities and after taking some time to recover and address neglected responsibilities on the home front, we will decide which ones to pursue.