Endeavour's Launch Once More Delayed

schleprock63 writes "NASA has delayed the launch of Endeavour due to inclement weather, mostly lightning. According to NASA, 'Cumulus clouds and lightning violated rules for launching Endeavour because of weather near the Shuttle Landing Facility. The runway would be needed in the unlikely event that Endeavour would have to make an emergency landing back at Kennedy. Endeavour's next launch attempt is 6:51 p.m. EDT Monday. NASA TV coverage will begin at 1:30 p.m.'"

Comments

Re:Whatever happened to replacements for the shutt

[confused one]

they were all cancelled. Until the Columbia accident, Congress didn't seem too interested in funding a program to replace the shuttles. Right now, it's still not clear, with the funding for the Constellation program being in question.

Re:Whatever happened to replacements for the shutt

[FleaPlus]

Whatever happened to the considerable R&D projects to replace the shuttle with a new model?

Off the top of my head, here's a quick summary of the various serious efforts into creating new manned spacecraft over the past 10-15 years:

• DC-X: A low-cost VTVL prototype built under a $58 million contract, which is still regarded by many as an ideal approach to an orbital vehicle. Plans were to create incrementally larger versions of it which would eventually be able to attain orbit in a cost-effective fashion. Unfortunately, during one of its flight tests a field technician messed up the landing gear, so it fell over when it landed and was destroyed (1996). The company told NASA it'd need $50 million to build a new one, but NASA used the opportunity to cancel the project so it could instead give more funds to the billion-dollar X-33/Venturestar project. Its spiritual successors are John Carmack's Armadillo Aerospace and Jeff Bezos's Blue Origin. In fact, the secretive Blue Origin company has hired several of the former DC-X engineers. One of the Armadillo members has a great write-up of the DC-X here: http://media.armadilloaerospace.com/DCX/
• X-33: Interesting project which would have tested a bunch of fascinating technologies (e.g. composite cryogenic fuel tanks, metallic thermal protection, an aerospike engine, lifting body design). Unfortunately, NASA really should've tried testing those technologies individually first, instead of putting every single one of them in the critical path of a new vehicle design. Oops. I believe the main problem ended up being the composite fuel tank, and when that failed the entire project (which had used up a billion dollars thus far) had to be canceled in 2001.
• Orbital Space Plane: A low-cost vehicle intended to launch on already-existing EELVs, started in 2003 and expected to start carrying crew by 2010. In 2004, this project was transferred to the Crew Exploration Vehicle project.

Now, the currently ongoing projects and contenders:

• Crew Exploration Vehicle: This is a little complicated. Back in 2004, the Crew Exploration Vehicle was announced, and it was assumed it'd be similar to the Orbital Space Plane project it derived from: a low-cost capsule which could be launched on already-existing EELV rockets like the Delta IV Heavy or Atlas V. This went through a number of stages of design studies and competitive flight tests planned, with unmanned tests by 2008 and unmanned tests sometime in the 2010-2014 range. Unfortunately, in 2005 Michael Griffin came in, proclaimed that he had a superior design and tossed out all the prior work. Although he claimed his design was simpler and faster, and commissioned NASA studies to "prove this," history has pretty well proved that his design (now the Ares I) was nowhere near as simple and straightforward as he thought it would be. Instead of the plan to have low-cost CEV launching on existing vehicles it had before, NASA currently has the Ares I which has an ever-increasing cost, currently around $35 billion. The per-launch cost is also expected to be as much as or higher than the space shuttle. Oops.
• DIRECT: A bunch of undercover NASA engineers who didn't believe Ares was the best solution but were afraid of retribution from Griffin, so they anonymously released a plan they thought was superior. Since it's Shuttle-derived it's certainly more expensive than an EELV-based design, but would have a larger payload.
• EELVs: These rockets are already used regularly to launch payloads for NASA and private industry, and most of the final proposals for the pre-Griffi

Re:Whatever happened to replacements for the shutt

[Anonymous Coward]

They used and still use older model CPU's because they are much easier to radiation harden. I'm sure you can appreciate that when you're traveling thousands of miles an hour you would prefer your flight controls to display correct alpha-numeric properties. Radiation hardening is much more important than processing power, it's not like they're playing Crysis up there or anything (that I know of anyway).

Re:Whatever happened to replacements for the shutt

[FLaSh SWT]

it's not like they're playing Crysis up there or anything (that I know of anyway).

Crysis! They can't even watch DVDs up there, remember?

Closest to Equator?

[tjstork]

Who's bright idea was it to put the main launch facility in *Florida*.

I think the deal is that the closer to the equator you launch from, the cheaper it is. That's why the French launch Ariane from a complex in French Guyana.

Not quite...there are more reasons

[Kupfernigk]

Conservatism about CPUs comes for a variety of reasons, all of which I like. First, it is much better to use an inherently rad-hard technology than to radiation harden an existing design. Rad-hard technology tends to lag commercial technology because it is much, much more expensive. Second, however, modern processor technology is in some ways the enemy of reliability. With things like out of order execution, multilevel cache and the release of cpus that have minor microcode bugs that are fixed with CPU drivers, it's hard to produce a verified design. Back in the days when I was doing this stuff, the RCA1800 (damn slow), Texas 9989 (good) and the Ferranti F100-L (bad) all had designs simple enough to be fully verified with the tools available, and when you wrote code for them you could actually be sure of exactly what it would do on a clock cycle by clock cycle basis. MMUs add another layer of potential unreliability, so for mission critical stuff a processor with a flat memory architecture where it is possible to state exactly what variable may occupy any memory location at a given point in program execution obviously offers more security blanket per dollar. (Both the CPUs I mention have minimal registers, so that everything gets stored in independently testable external memory.

Modern designs are amazingly reliable given their complexity but, as you say, you want to be very sure once out of the stratosphere that you know exactly what your little thinking machine is thinking.