However having supported almost a hundred Shuttle landings, some very close to the margins, many others waved off because conditions were not ideal,
Shuttle landings were unpowered. Due to them needing 5 mile visibility (because STS was not certified for instrument landing) and sitting on tires that were only rated to c 188knots landing speed if conditions were not *perfect* then reentry did not take place. Proposals as simple as changing some of the autopilot constants and logic could have fixed this.
Wingless lifting bodies were first investigated because in the early 60's it was doubted that any material could be found that would tolerate the aerodynamic heating of a sharp leading edge.
ACtually Reinfoced Carbon Carbon dates from around this time and was IIRC one of the options for the X20 Dyan Soar nose. For this kind of reentry it's not *peak* temperature given by rate of heat input (q dot) it's *total* heat input (Q) that was the problem.
The Shuttle had wings because the necessary materials were developed and because, after over a decade of trying, there was no lifting body that could approach the performance of a winged vehicle. The Shuttle had better aerodynamic performance than any lifting body, even though they were boat-tailed and the Shuttle had huge engine bells that caused almost half its drag. With the tail cone installed the Shuttle has twice the L/D of the best wingless lifting body, an unimaginable difference in aviation, and that becomes particularly important as landing mass is increased. If you want more drag, you can always deploy a speed brake. If you want more lift (with the separated wing and tail of the X-37) you can lower the flaps. Just my opinion. Feel free to disagree.
The *big* driver for wings was the USAF demand for return to launch site after 1 orbit. This required *huge* cross range, relative to a capsule design. IIRC the FDL5 lifting body design would have *global* cross range (Hypersonic L/D of something like 3.5) but would have made it a joint NASA/USAF programme (and I'm not sure if the FDL5 was still classified at that time).
BTW Orbiter wings are not "sharp" by conventional aircraft standards *relative* to the the size of the vehicle. AFAIK the shock front is still detached and in front of the leading edge.
The attractions of lifting bodies are the reduced acreage of TPS (The NASA TPS database lists replacement costs of tiles as $12000/m^2 nd blankets as $3000/m^2) and improved volumetric efficiency. You need a smaller planform and you can put stuff on top of most of the *area* of that plan form. http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070017478_2007014601.pdf
A *very* nice paper. Interesting to see that what looks to be one of the design rules of thumb (Hoerners) is roughly 3x too small, which suggests some promising ideas that were evaluated with it (and failed) might have worked in IRL just fine, or vice versa (but got cancelled for other reasons before anyone tried to build them).
It's good to know people are still mining this data and not taking historic rules of thumb as gospel.
I hope designers of the *next* generation pay attention to the results.
[unit change mph to knots.Deleted YT link]