Inverse Engineering

Project
Sea Launch

Post-flight Analysis

With all the hurdles in the way of this project it almost never happened. The flight waiver from the FAA arrived three days prior to the launch and up to that point we still didn't have a boat lined up. Things just fell into place the last few days and what was going to be a canceled launch the week before turned out to be a great experience even though one rocket turned into a torpedo.
Two rockets were built for the Sea Launch. Each had waterproofed exteriors, fins and electronics bays. The ignition and recovery for the rockets was handled by solid state time delay relays while the ignition circuit for the engines was through a four pole ice cube relay.
The first rocket ignition system went off prematurely while it was being held over the side of the boat. We dropped the rocket and it sunk a few feet before the engines lit and it took off underwater with a plume of exhaust bubbles behind it. The cause is still a mystery but there was a large amount of sea water splashing about and it's possible some got into the electronics bay.
There were so many problems once we got out to the launch site that I hadn't anticipated. Float testing in the pool is entirely different than the ocean with currents and swells and increased buoyancy due to the salt water. Hanging off the side of the boat while it bobbed up and down on the waves made access to the rocket difficult at best. The ocean movement is so dynamic that even though the float system did not work properly, looking back, most of the other designs discussed would not have worked either for one reason or another.
Going out to sea was a very good learning experience and will provide invaluable education for the next Sea Launch this summer.
The float system of four 8" diameter floats around the rocket nose worked well to keep the rocket above the water but there were many design problems associated with it as well. The floats kept falling off the taper pins when a wave would move the rocket up on one side but not on the other. The taper pins were not long enough and the rocket wanted to float on it's side rather than down in the water.
The second rocket had duct tape holding on the floats just so we could keep it boyant but the problem of the rocket floating on it's side could not be solved at the site so it was launched at a horizontal angle. The Coast Guard had cleared a three nautical mile radius around the launch site prior to ignition. One float managed to stay on the rocket throughout it's short flight.
Total take-off weight of each rocket was 38 lbs. and each rocket had four J300 engines.

Construction