From: vince@offshore.ai (Vincent Cate) Newsgroups: sci.space.tech Subject: Re: Heat Sink Heat Shields References: <5dcb47db.0310011151.51d744ce@posting.google.com> <9186edb5.0310012120.758e3a2a@posting.google.com> <9186edb5.0310051121.737e64cd@posting.google.com> NNTP-Posting-Host: 209.88.68.230 Message-ID: <9186edb5.0310100757.4eb9f134@posting.google.com> vince@offshore.ai (Vincent Cate) > Do you know what sort of trajectories they fly? Like do they come in > at a very high angle? If I simulate 7.7 km/sec coming in at 45 degrees > it generates like 1/8th the total heat of coming in at 0 degrees. My new book is answering all kinds of questions. On page 128 it has a graph showing the heating rate per square foot vs exposure time for ICBM, IRBM, Mercury, Gemini, Apollo, X-15, B-70 etc. The time for ICBM is just over 0.1 min, while IRBM is around 0.2 min and Apollo is just under 10 min. So the missiles have very steep trajectories compared to manned vehicles, and so have much higher G loading but lower total heat per Kg. And that explains why they can use copper. The book is "Re-entry and Planetary Entry Physics and Technology - II / Advanced Concepts, Experiments, Guidance-Control and Technology" By W. H. T. Loh, 1968 -- Vince