Another Leak Delays Final Discovery Launch 104
vsolepr writes "Today's scheduled launch was scrubbed because of a gaseous hydrogen leak near the spacecraft's external tank. This is the fourth time in the past week that Discovery's launch was delayed due to various leaks and electrical issues. NASA now is aiming for a launch date no earlier than Nov. 30."
Comment removed (Score:3, Interesting)
Re:Silly assumption (Score:4, Interesting)
Unless something was not the best idea in the first place, and even worse implementation (did the Shuttle deliver on any of its main points, as advertised?)
60s, 70s...its designers probably raised on scifi with a whole lot of spaceplanes - no doubt influenced by huge airplane advances in the 40s. Which differed quite a lot from those 130 year old depiction of "our" times [goo.gl] (/. & links with unicode...), apparently influenced by rapid advances in (sub?)marine technology. We can build them (take a Harrier, remove wings and canopy), but it doesn't make those past dreams a good idea. Not a lot flying boats around nowadays, too.
Re:Ugh (Score:3, Interesting)
Energia would be probably nice, yes, in launches without Buran (but still probably not very cost effective due to scale and rarity of the launches). HOTOL was apparently dropped when it became clear that a rocket using the same technological advances would be at least equally effective (but much less complex). And you would want to up the size of the Shuttle?
An orbital launcher flies most of its mission outside the atmosphere. Most of its mass is reaction mass. That, together with what the rocket equation is, probably means a pure rocket will be able, for a long time, to better use technological advances necessary to make a true spaceplane even barely possible.
But perhaps such advances are not even the best way, perhaps simple mass-production would be better. We had a test run [fourmilab.ch], with the first widely used rocket; too bad the orbital effort in such style [wikipedia.org] was killed.
Re:Silly assumption (Score:4, Interesting)
Point me to a genuine major advance in airframe materials, thermal protection systems, or rocket engine design since the 1970s and maybe this contempt might be better supported by actual evidence.
That's a very valid point, most people don't realize that there never will be any "magic" improvements in rocketry to bring the cost down to the point that we'll all be taking holidays on Mars. It's still a high-energy problem, and new technology doesn't necessarily make the hard problems much easier.
There have been improvements though, they're just not that big or visible. For example, computer-aided design would allow a new rocket to be extensively modeled without expensive testing. Multiple design and testing iterations could be performed without ever stepping into a machine shop. This in turn allows design simplifications, a reduction in part counts, etc...
Computer-aided machining has made enormous improvements since the seventies, in part complexity, cost, precision, and the type of materials that can be used. Old designs would not have assumed the availability of CAM, so they might rely on manual steps, such as welding and riveting. To use parts made automatically by machines, a design optimized for that manufacturing process is required.
There have been significant materials-science advancements, which is why both Boeing and Airbus are now creating aircraft made of composites, which wasn't practical or cost-effective in the 70s. Of course, some of these advancements have made it into the shuttle, for example the Super Leightweight Tank [wikipedia.org] is made of a high-tech aluminium-lithium alloy. That's an easy part to replace, but upgrading the orbiter would be essentially a redesign, so it has remained relatively unchanged.
The real problem with the shuttle is that the fundamental concept is flawed. It assumes that people are needed in orbit -- robots do a better job now, thanks to advancements in digital electronics. In turn, the original design also assumed that it's worth reusing the container for those people. If there are no people, nothing needs to be reused. The engines might be worth bringing back down, but a small ablative heat-shield and a parachute is more than enough for that, there's no need to build a huge heat-shielded structure with wings and avionics! When it costs $thousands per kg of material sent into orbit, anything not directly serving the purpose at hand is just waste. The orbiter weighs 68,585 kg empty, of which only 9,531 kg is the engines! Not counting the structure required to protect the payload, the remaining 50 tons of shuttle structure is just a huge waste of money. That 50 tons could be payload on every launch. Over the 100+ launches that have occurred, that's 5000 tons of satellites or space probes that could have been launched. A large satellite is 5 tons, so that's over a thousand that could have gone up, but didn't. Just imagine: if only 10% of those were for solar system exploration, we could have had a hundred or more additional space probes out there among the planets!
Re:Silly assumption (Score:3, Interesting)
That's a very valid point, most people don't realize that there never will be any "magic" improvements in rocketry to bring the cost down to the point that we'll all be taking holidays on Mars. It's still a high-energy problem, and new technology doesn't necessarily make the hard problems much easier.
The ultimate limit on the cost of getting into orbit is the cost of rocket fuel, which is not a lot. What is needed is reliable, reusable launchers which don't require months of maintenance by thousands of people between flights, and that's perfectly possibly with enough engineering effort... the idea that it will 'never' happen is just silly.
If there are no people, nothing needs to be reused.
So we should build single-use container ships and sink them after they've crossed the ocean once?
Reusability is _the_ biggest cost-saver possible, so long as it doesn't require the massive maintenance that a shuttle does between flights (not to mention the cost and complexity of the external tank and boosters).
Of course it could be better - just look at it (Score:3, Interesting)
The main factors that made it like this were a requirement to be able to get into orbits that require a lot of fuel if you are going from Florida and the problems associated with making the thing taller than it is to have enough fuel to get into those orbits. I don't know how many missions it was used for that actually needed that, they were apparently classified military missions but it's not as if you can hide the thing up there so some astronomers would known how many times it went into polar orbits. I can't say if the compromise was worth it and the seven lives lost due to a chain that started with the compromise, only somebody that knows the worth of the polar orbit missions and if they really had to be manned anyway could say.
A shuttle designed to get to equatorial orbits would look very different and have better lifting capacity than rockets that have to handle great bit weights strapped to the side and the extra mass required to make it strong enough to do so.
Personally I think it was wasted sometimes on "space truck" missions that didn't need to be manned in the first place and could just have been done with a larger conventional rocket than our current satellite launchers, but every mission probably did something useful since there's a few crew working on things even if the primary goal is just to deliver stuff.
Re:Ugh (Score:3, Interesting)