Path: utzoo!attcan!uunet!wuarchive!usc!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!ames!skipper!shafer From: shafer@skipper.dfrf.nasa.gov (Mary Shafer (OFV)) Newsgroups: sci.space.shuttle Subject: Re: Will we lose another orbiter Message-ID: Date: 11 Apr 90 16:03:09 GMT References: <1990Apr6.024844.16083@utzoo.uucp> <2836@rodan.acs.syr.edu> <1990Apr8.050005.23425@utzoo.uucp> <450@gazette.bcm.tmc.edu> <1990Apr11.041856.21663@utzoo.uucp> Sender: shafer@skipper.dfrf.nasa.gov Organization: NASA Dryden, Edwards, Cal. Lines: 58 In-reply-to: henry@utzoo.uucp's message of 11 Apr 90 04:18:56 GMT In article <1990Apr11.041856.21663@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article shafer@skipper.dfrf.nasa.gov (Mary Shafer (OFV)) writes: >>> ... Can the crew survive a belly landing, >>> can the vehicle survive such a landing... >>It's highly probable that the crew will survive and that the vehicle >>will survive with only minor damage. Airliners land gear-up fairly >>often, are repaired, and fly again quite nicely, for example, and the >>Shuttle is much sturdier than an airliner... >Sure about that, Mary? My impression was the other way around: the >orbiter is relatively fragile. Certainly a ditching in water is >considered completely unsurvivable, with serious structural failure >likely (unless the assessments have been revised radically since the >Rogers report); that's why the crew now has a bailout system. I can't >find a definitive statement about a belly landing, although (astronaut) >Paul Weitz told the Rogers commission: > "My feeling is... strong that the Orbiter will not survive > a ditching, and that includes land, water, or any unprepared > surface..." I based my remarks on conversations with the folks who were working on the gear and braking systems (the infamous nosewheel steering!) and that's what they think. However, notice the difference in scenario--Paul refers here to _ditching_, on an unprepared surface. We were talking about a gear-up landing, on a prepared surface (i.e. the runway or lakebed). I am quite willing to say that the Shuttle will not survive a ditching, no matter where the gear is. >>I've always thought that a landing accident is somewhat likely, BTW, >>but I think it likely that the vehicle won't be destroyed, just >>damaged. The crew is very likely to survive, probably uninjured. >As I recall, both NRC and OTA (in studies on future shuttle operations) >hinted that a hard landing was the single most likely reason to write >off an orbiter, and that the crew would quite possibly survive. Part of the question here rests on writing off vs. repairing and the other part rests on what a hard landing is. Airliners are repaired fairly cheaply, compared to the replacement cost, and both the cost and technique are well-known. As for the Shuttle, who knows? I think that there'd be a strong inclination to repair, not write off. Now what's a hard landing? Too high a sink rate, so that you bottom out the gear, or driving the gear through the wings, or scraping the belly off on the runway, or rolling the vehicle up into a ball of crumpled metal? To me the first three are damage, the last is destruction. So even a hard landing is a question of degree. But yes, the Shuttle is vulnerable to landing accidents. -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA