However having supported almost a hundred Shuttle landings, some very close to the margins, many others waved off because conditions were not ideal,
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.
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.
Proposals as simple as changing some of the autopilot constants and logic could have fixed this.
Quote from: john smith 19 on 08/21/2012 03:04 pm Proposals as simple as changing some of the autopilot constants and logic could have fixed this.Not true by any means.
Ok zerm took your advice and looked it up.Here's a couple of good links I found. I didn't know who these guys were before so thanks for enlightening me. http://www.nasa.gov/centers/dryden/news/NewsReleases/2005/05-13_prt.htmhttp://www.nasa.gov/centers/dryden/news/Biographies/Pilots/bd-dfrc-p018.html
“The CDR is a critical DDT&E milestone, where the contractor discloses its complete spacecraft system design in full detail, identifying areas where technical problems and design anomalies have been resolved,” the document states.“Successful completion of the CDR will validate that the contractor’s spacecraft design maturity is at an acceptable level that justifies the decision to initiate fabrication/manufacturing, integration and verification of the flight hardware and software.”
This article on Orion's CDR in 2015 also explains what CDR is for a spacecraft such as Orion but it should also fit for DC:http://www.nasaspaceflight.com/2012/01/eft-1-spring-2014-launch-date-contract-negotiations/Quote“The CDR is a critical DDT&E milestone, where the contractor discloses its complete spacecraft system design in full detail, identifying areas where technical problems and design anomalies have been resolved,” the document states.“Successful completion of the CDR will validate that the contractor’s spacecraft design maturity is at an acceptable level that justifies the decision to initiate fabrication/manufacturing, integration and verification of the flight hardware and software.”In any event, DC will almost get to CDR at the end of the CCiCap base period in 2014 but not quite. I hope that NASA will exercise the CCiCap optional milestones that will allow it to get to CDR prior to making any further down selection in 2014 or 2015.
The optional milestones have been redacted because they were considered to be propietary. So nobody knows for sure. Gerst only said that DC had optional milestones that could get them to CDR if they are exercised by NASA.
I saw the redaction too, SNC appears to have a good record of completing milestones on time, with some luck they will make there schedule and see the extra milestones added.