Guest: Dave Ketchledge. Topics: Mars Lander Choices. Please direct all comments and questions regarding Space Show programs/guest(s) to the Space Show blog, http://thespaceshow.wordpress.com. Comments and questions should be relevant to the specific Space Show program. Written Transcripts of Space Show programs are a violation of our copyright and are not permitted without prior written consent, even if for your own use. We do not permit the commercial use of Space Show programs or any part thereof, nor do we permit editing, YouTube clips, or clips placed on other private channels & websites. Space Show programs can be quoted, but the quote must be cited or referenced using the proper citation format. Contact The Space Show for further information. In addition, please remember that your Amazon purchases can help support The Space Show/OGLF. See www.onegiantleapfoundation.org/amazon.htm. For those of you interested in the opportunity to submit feedback on the NRC congressionally mandated Human Spaceflight Study, please go to www.nationalacademies.org/humanspaceflight. Please remember that your Amazon Purchases Can Help Support The Space Show/OGLF (http://www.onegiantleapfoundation.org/amazon.htm). We welcomed Dave Ketchledge back to the program to discuss Mars precision human spaceflight lander choices. During the first segment of our 2 hour 13 minute discussion, we covered Dave's basic thesis and analysis regarding landing large payloads on Mars and the need for very accurate and precise landings for the human spacecraft. While at times the first segment was technical and perhaps complicated, it provided the necessary groundwork and foundation for our discussion during the second half of the program. During the first part, Dave explained the need for a precision human landing on Mars, the difficulties in doing that, the pros and cons of the various shapes to use for the human spacecraft, and why the Pershing 2 missile nosecone offered the best shape and design. Dave cited his references for his analysis and conclusions. In the second segment, we started with a listener question about the origin of the DC-X vehicle design as it was related to the analysis, conclusions, and explanations Dave provided earlier in the discussion. Dave continued his comparison and analysis of the three potential vehicle designs, then I asked a series of questions sent in by listener Curt from the recently held Humans to Mars conference regarding issues in landing a large payload on Mars. Dave also spoke about heavy lift and the need for an SLS type vehicle, speaking to the additional needs for using smaller launches. These needs include planning on replacement launches and payloads which must be figured into the costs as all the advance launches of supplies & materials to Mars will be mission critical launches. The crew should be the last launch to the planet. Listeners both emailed in questions for Dave and additional listener phone calls were received. Dave continued to reference the NASA Mars Design Study, work done by JPL, Dr. Robert Manning, and others. We talked about the Mars One program & how it might land its human crew on Mars. We also talked about HSF to Mars policy &the absence of political leadership for a human mission to Mars. Dave addressed media issues but largely stayed with the shape of the human spaceflight spaceship, the need for a precision landing, and what might work best. Please post your comments/questions on The Space Show blog above. You can email Dave at the address he provided on air at the end of the show.