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Lunar lander ideas over the decades
On Jun/21/2020 at 12:09, Jeff Findley wrote :
In article , says... On 2020-06-19 7:46 PM, Alain Fournier wrote: Wow, you actually saw the moon missions live. You must be an old man. Not to mention witnessing, in person, the launch of Columbia on STS-1. I'm 51, so don't remember Apollo at all. But I do remember STS-1 and beyond. STS-1 was ground breaking for its time. Unfortunately, the press never picked up on the many things that went wrong with STS-1 besides perhaps the obvious missing silica tiles that fall off. Even NASA still isn't terribly forthcoming about all of the issues. Cite: https://www.nasa.gov/centers/dryden/...lls_sts-1.html No mention of the body flap (that was almost a very bad day) or the flight control system issues. Here is a cite for the body flap issue: First Time Lucky: The Space Shuttle?s Dicey Inaugural Mission BY TERRY DUNN ON JAN. 16, 2018 AT 8 A.M. The story of STS-1. https://tinyurl.com/ybvsthrh Cite for the flight control system issue (Mary Shafer used to be a regular poster here): Extraction of stability and control derivatives from orbiter flight data Author and Affiliation: Iliff, Kenneth W. (NASA Hugh L. Dryden Flight Research Facility, Edwards, CA, United States) Shafer, Mary F. (NASA Hugh L. Dryden Flight Research Facility, Edwards, CA, United States) https://ntrs.nasa.gov/search.jsp?R=19940006252 https://ntrs.nasa.gov/archive/nasa/c...9940006252.pdf Stability of an aircraft/spacecraft at high mach numbers is a bigger problem than most believe. I had a friend who did computer fluid dynamics for the European Hermes spacecraft programme in the late 1980s and early 1990s. He was supposed to confirm the stability of the spacecraft design. He told his bosses that his computations were not conclusive and that the vehicle, as designed, was probably stable enough but it wasn't a sure thing. He recommended tweaking the design to make it more stable. That, together with other modifications asked by other people working on the project, added delays and additional costs. The programme was scrapped before my friend had a design he could guarantee was stable. When NASA designed the space shuttle, they had nowhere near the computing power my friend had for Hermes. (We were jealous of the computers he was using with several GB of RAM, most people at the time had computers with a few MB of RAM, I was working on a computer that most people thought was amazing with 600 MB of RAM, that computer I was working on had cost hundreds of thousands of dollars.) NASA had done a lot of wind tunnel testing for the Shuttle, but that doesn't allow for as much iterations as computational fluid dynamics. All worked out well for the Shuttle. That's what my friend was saying would happen with Hermes, he was saying it was probably stable but he wasn't sure. So if Hermes had flown as it was first designed, the outcome would probably have been as for the Shuttle: it works, now that we have flown it, we know it. Note that capsules are much easier in this respect. Alain Fournier |
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