Comic Discussion > QUESTIONABLE CONTENT
WCDT 22-26 August 2011 (1996-2000)
Boradis:
--- Quote from: Carl-E on 28 Aug 2011, 12:52 ---I'm no nuclear engineer. I have no idea what kind of revolutionary propulsion system he had in mind, and neither do you. Just because you can't adapt existing reactor systems to spaceflight doesn't mean there isn't some neutron-shedding reaction that will push a rocket through space!
--- End quote ---
There's plenty of reactions that will do just that. The problem is they irradiate the hell out of the launch site. The most famous of which being ...
--- Quote from: Is it cold in here? on 28 Aug 2011, 18:20 ---Nuclear propulsion for the really hardcore
--- End quote ---
--- Quote from: Akima on 28 Aug 2011, 16:27 ---I've been thinking about this since you posted it, and I'm not sure that I buy it. I know that climbing out of the gravity well is very difficult, but it hasn't become any more so since Apollo 17 brought crewed spaceflight beyond Earth's orbit to an end. In 1972. Nearly 40 years ago. Using technology developed back in the 1960's.
--- End quote ---
Unfortunately physics hasn't changed either since at least the epoch of inflation.
Advancing spacefight is not as straightforward or easy as Moore's Law. The issue with rockets isn't miniaturization or refinement of design -- it's power. All of the math involved in making a rocket fly has been known for centuries, so that's a very mature field. There's an unavoidable reason rockets are almost all fuel.
Further refinements can make them safer, but barring something radical like Orion or one of the other speculative nuclear rockets mentioned by Akima, they can't make them more powerful.
When I wrote these articles (the "Beanie Baby Satellite" story) I spoke with rocket scientists routinely. It's not like they're sitting on their butts about things like this. They'd like nothing better than to put up more spacecraft. There's also a lot of money just waiting for someone to find a better way into space, even without there being oil on the Moon or whatever.
But until something more powerful and at least as safe as liquid oxygen plus kerosene or liquid hydrogen is discovered -- at least the power of a nuclear bomb without radiation -- it will take a Saturn V -worth to go anywhere beyond sub-orbital thrill rides.
Skewbrow:
Yup. Just to give you some numbers. To reach a space orbit you need Mach 25 or thereabouts (don't want to do the math any more accurately), to climb out of Earth's gravity well you need about Mach 35. (this would be the speed you need to have when leaving atmosphere in order for the Earth to not pull you back in, unless you can keep accelerating after that point).
The X-15 (a U.S. test plane from the 1960s) reached Mach 6 and it was rocket powered (and needed to piggy-back a jet to get started, it couldn't take off on its own power). `Spaceship' One went a inch higher, but only reached Mach 3. I don't know what's the world record of jet powered aircrafts. I guess military planes may have topped Mach 3. AFAIK Concorde was the fastest commercial aircraft with a notch over Mach 2.
And I don't think that it is due to lack of funding for propulsion research. After all, any propulsion system could also be used to deliver weapons, so the military would support the idea, if it were at all feasible.
Looks like we need that space elevator. Getting to geostationary orbit "free of charge" reduces the escape velocity quite a bit. More importantly, upon re-entry you can give the energy back to something else on its way up.
Akima:
--- Quote from: Boradis on 30 Aug 2011, 01:55 ---When I wrote these articles (the "Beanie Baby Satellite" story) I spoke with rocket scientists routinely. It's not like they're sitting on their butts about things like this. They'd like nothing better than to put up more spacecraft. There's also a lot of money just waiting for someone to find a better way into space, even without there being oil on the Moon or whatever.
--- End quote ---
But that's the thing. We don't even have the same capability we had in 1968. There are no Saturn V rockets any more, never mind anything better using modern materials. We've gone backwards in our ability to lift payload into orbit, not forwards, for all the non-butt-sitting your rocket scientists have been doing. That isn't because the technical challenges became any greater, but because of political/managerial decisions.
Mr_Rose:
Technically there is still one nearly complete Saturn V stack left, but it was left out in all weathers for twenty years and I doubt it'd be ready to fly in less time than it would take to just build another one from the blueprints.
You're totally right about the main problem being not enough politicians with the balls to just come out and say "spaceflight is way more important than profiteering off wars you fucks! Let's get it done already!" though.
Carl-E:
OK, heard a joke that actually fits here...
Three surgeons were arguing over who was easiest to work on. the first said, "Electricians - everything inside is color coded!"
The second sez "No, it's Librarians - everything's in alphabetical order!"
The third one tells them they're both wrong. "It's politicians. There's no guts, no heart, no spine and no balls, and their head's interchangeable with their ass."
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