Broadcast 1290 (Special Edition)

14 Jan 2010 Dr. John Hunter
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Guest: Dr. John Hunter. Topics: Hydrogen gas gun, low cost space access, space physics and engineering. Dr. John Hunter, President of Quicklaunch, Inc, was our guest today to discuss the hydrogen gas gun for launching payloads to space. Please visit their website at I urge you to listen to Dr. Hunter's Google talk which you can access by clicking on the arrow on the Quicklaunch home page. In our first segment, Dr. Hunter provided us with an overview of the Quicklaunch gas gun, the rocket assisted second stage, and the physics/engineering supporting the use of the hydrogen gas gun. Several skeptical listeners called or sent in questions and at times our discussion was technical, dealing with the drag on the vehicle, the shape of the vehicle to withstand very high G loads and stresses. Dr. Hunter went through the physics and engineering, plus the history of similar hydrogen gas guns and other projects in the past, including SHARP with the Lawrence Livermore National Laboratory. See what you think of these discussions and the data. In our second segment, Dr. Hunter was asked some comparison questions regarding the Space Shuttle, Space X, building an RLV, and the cost to space with a chemical rocket. Later in segment, he outlined his four phase plan for Quicklaunch, including the time frame for each phase. Listen carefully to these plans with Phase 1 starting at White Sands as a demo or stunt phase. He also talked about payload sizes for each phase all the way up to 1,000 lb. payloads unless the gun is made larger. Note what he had to say about demos and stunts as his comments may surprise you. As you will hear, eventually in the later phases, the Quicklaunch gun would be mostly underwater. Before the segment ended, we talked about the materials used for the gas gun including high strength aluminum 70-75 and Toray 740. In our third segment, Dr. Hunter received some questions about guidance control and the 25 degree inclination used for the gun. Our guest said there would be no rifling in the gun's barrel as it had to be smooth bore. He fielded additional questions about velocity loss due to drag. Don't miss this comprehensive discussion of the specs. He also described the dimensions of the gun and using a version of it from the Moon or even Mars. Our guest provided us with a thorough economic analysis of lunar vs. Martian access and this is a must listen to discussion. The program Dr. Hunter talked about requires orbital propellant depots and other space infrastructure. Listen to what he said in this part of the discussion about the traditional aerospace and Military Industrial Complex in building this infrastructure as opposed to Quicklaunch providing the space infrastructure. Toward the end of this segment, we talked about why we go to space, the importance of human space exploration, and connecting space with the interests of the general public. Our fourth and final segment started off with a space elevator discussion and then Dr. Hunter provided us with his three top choices for launch systems. We veered off topic to discuss his experiences with helping to build armored gun vehicles for use in Iraq. Near the end of the program, Dr. Hunter commented on the U.S. Civil Space Program and its impact on Quicklaunch. Listen to what he had to say about that. His last question dealt with SSP which he said was non-trivial. Don't miss all his comments on space solar power. If you have questions or comments for Dr. John Hunter, please send them to me at and I will forward them to Dr. Hunter.