|
Okan170 posted:So basically everything that ever happened to the Shuttle (from foam to SRBs) was brought on by this design choice? Why did the orbiter need to have main engines anyway? Even the version we got couldn't use them on orbit or landing, they're just there for thrust during ascent. Probably something like "The rocket engines are expensive and complicated to manufacture, a shame we can't re-use those too, why don't we just stick them on the shuttle!"
|
| # ? Feb 20, 2013 23:04 |
|
|
|
| # ? May 23, 2013 22:56 |
|
|
Okan170 posted:So basically everything that ever happened to the Shuttle (from foam to SRBs) was brought on by this design choice? Why did the orbiter need to have main engines anyway? Even the version we got couldn't use them on orbit or landing, they're just there for thrust during ascent. Being able to bring the main engine home seemed like a good idea.
|
| # ? Feb 20, 2013 23:04 |
|
|
Okan170 posted:So basically everything that ever happened to the Shuttle (from foam to SRBs) was brought on by this design choice? Why did the orbiter need to have main engines anyway? Even the version we got couldn't use them on orbit or landing, they're just there for thrust during ascent. The dream of the Shuttle back in the '60s was a completely reusable, single-stage-to-orbit vehicle which could then reenter and land on a runway. As it went from dream to reality, it became clear that that goal was unattainable, and there were going to have to be some parts that were cast away during launch. The decision was to go for maximum reusability, which then forced all the rest in a cascade of after-effects. They ultimately went for an external fuel tank so as to maximize the utility of the orbiter, which was relatively cheap and they felt they could afford to throw away. Liquid-fueled external boosters would have provided more thrust and been cheaper in the long run, but more complicated and expensive to develop in the short run. They went with SRB's because they could be made functional sooner and easier.
|
| # ? Feb 20, 2013 23:16 |
|
|
Slo-Tek posted:Being able to bring the main engine home seemed like a good idea. But I think his point is seemed like a good idea to who? Because, while bringing the main engines back does represent a cost saving, it's laughable compared to the money wasted designing new engines and an entirely new, less versatile launch stack instead of using the Saturn. Not to mention making an already heavy vehicle even heavier. It's the budgetary equivalent of driving 100 miles out of your way to save $0.05/gallon on gas.
|
| # ? Feb 20, 2013 23:16 |
|
|
If I remember correctly, the original anticipated refitting cost of the shuttle between launches wasn't supposed to be anywhere near as high as it ended up being. Therefore, leaving the engines on it would have been a huge cost savings. It ended up costing so much that in retrospect it would be cheaper to discard the launch equipment every time, but that's not the fault of the original plan for maximum reusability.
|
| # ? Feb 20, 2013 23:24 |
|
|
http://www.youtube.com/watch?v=rBgkrhnThek The Shuttle is a way old concept, we see it in this Disney film Von Braun advised on in 1955. This was made Pre-Sputnik when no one took space exploration seriously. The full movie is on youtube. Really cool stuff. It went through decades of bureaucracy and a loss of funding/enthusiasm for space technology.
|
| # ? Feb 20, 2013 23:29 |
|
|
rolleyes posted:But I think his point is seemed like a good idea to who? Because, while bringing the main engines back does represent a cost saving, it's laughable compared to the money wasted designing new engines and an entirely new, less versatile launch stack instead of using the Saturn. Unless you're launching every couple of weeks. The more you launch, the more benefit you get from reusability, so if you're going to promise an absurd amount of launch capacity you're going to want to maximize reusability along with it.
|
| # ? Feb 20, 2013 23:34 |
|
|
Phanatic posted:Unless you're launching every couple of weeks. The more you launch, the more benefit you get from reusability, so if you're going to promise an absurd amount of launch capacity you're going to want to maximize reusability along with it. That raises another question, what was the quickest turn-around time for the orbiter between missions?
|
| # ? Feb 20, 2013 23:35 |
|
|
Breaky posted:That raises another question, what was the quickest turn-around time for the orbiter between missions? Fastest ever achieved was pre-Challenger in 1985, at almost .80 launches a month. That was unbelievably back-breaking according to the grey-beards who worked management in those days. They had originally had a max launch rate of 52 launches a year, with over ~40 being necessary for the recoverable aspects of shuttle to become economically viable. Edit: Oops, I think I misunderstood your question. In the 80's you saw individual orbiters flying every ~3 months give or take. Omnicarus fucked around with this message at Feb 20, 2013 around 23:46 |
| # ? Feb 20, 2013 23:43 |
|
|
Breaky posted:That raises another question, what was the quickest turn-around time for the orbiter between missions? The shortest turn-around for a shuttle was between the two first flights of Atlantis at 7 weeks. -e- It's ridiculous how some shuttles sat around for years later on.
|
| # ? Feb 20, 2013 23:49 |
|
|
Okan170 posted:Nope, they were going to put it on top!. My original reaction was something like  but I'm even more surprised that such a design was actually superior to the one we all know.
|
| # ? Feb 21, 2013 01:28 |
|
|
In the quite unlikely event that Lockheed Skunkworks comes through on their claim to delever a prototype 100MW fusion reactor in 5 years and have them commerciably viable in 10, how would that impact the space program? http://www.youtube.com/watch?v=JAsRFVbcyUY
|
| # ? Feb 21, 2013 01:28 |
|
|
withak posted:Is that a huge sheet of glass on the front?
|
| # ? Feb 21, 2013 01:41 |
|
|
Breaky posted:If I remember correctly, the original anticipated refitting cost of the shuttle between launches wasn't supposed to be anywhere near as high as it ended up being. Therefore, leaving the engines on it would have been a huge cost savings. I think totally screwing up the cost estimates is a fault in the original plan. Good cost estimates is vital to any engineering that doesn't involve the government.
|
| # ? Feb 21, 2013 01:42 |
|
|
withak posted:Is that a huge sheet of glass on the front? Nope, it is just black paint to avoid glare off the nose. Same as the other orbiter in the box, and all kinds of cold-war era bombers that likely inspired the model makers. 
Slo-Tek fucked around with this message at Feb 21, 2013 around 01:47 |
| # ? Feb 21, 2013 01:45 |
|
|
Charlz Guybon posted:In the quite unlikely event that Lockheed Skunkworks comes through on their claim to delever a prototype 100MW fusion reactor in 5 years and have them commerciably viable in 10, how would that impact the space program? Energy is everything, so we're talking about an order of magnitude improvement over existing capabilities.
|
| # ? Feb 21, 2013 02:02 |
|
|
Charlz Guybon posted:In the quite unlikely event that Lockheed Skunkworks comes through on their claim to delever a prototype 100MW fusion reactor in 5 years and have them commerciably viable in 10, how would that impact the space program? Fusion is, was, and always will be 10 years away from being commercially viable.
|
| # ? Feb 21, 2013 02:21 |
|
|
Deteriorata posted:Fusion is, was, and always will be 10 years away from being commercially viable. I thought that was 20 years (ITER). Perpetually being 10 years away is significant progress!
|
| # ? Feb 21, 2013 02:35 |
|
|
Charlz Guybon posted:In the quite unlikely event that Lockheed Skunkworks comes through on their claim to delever a prototype 100MW fusion reactor in 5 years and have them commerciably viable in 10, how would that impact the space program? Satellites can be launched on the flying pigs that emerge from my rear end for extremely low cost.
|
| # ? Feb 21, 2013 02:50 |
|
|
Volmarias posted:Satellites can be launched on the flying pigs that emerge from my rear end for extremely low cost. On that note, Dennis Tito says he's going to Mars in 5 years.  http://www.wired.com/wiredscience/2...nnis-tito-mars/
|
| # ? Feb 21, 2013 03:18 |
|
|
Volmarias posted:Satellites can be launched on the flying pigs that emerge from my rear end for extremely low cost. I fail to see either correlation or causation. 
|
| # ? Feb 21, 2013 03:45 |
|
|
thehustler posted:ISS crew have requested a private conversation with MCC-H to get a debrief on the events of this afternoon and also to raise some concerns they had. Interesting. I'd be very interested to hear more about this.
|
| # ? Feb 21, 2013 05:54 |
|
|
Charlz Guybon posted:In the quite unlikely event that Lockheed Skunkworks comes through on their claim to delever a prototype 100MW fusion reactor in 5 years and have them commerciably viable in 10, how would that impact the space program? That video is delightfully vague. If they could manage it they'd probably win the nobel prize for physics and peace.
|
| # ? Feb 21, 2013 06:21 |
|
|
The Saturn Shuttle could never happen, because that's just too much goddamn sexy for one vehicle. They'd be a '69 Charger RT in the cargo bay away from a sexy singularity that would suck all of earth's sexy into a single, physics-defying point where the laws of sexy break down.
|
| # ? Feb 21, 2013 06:43 |
|
|
Charlz Guybon posted:In the quite unlikely event that Lockheed Skunkworks comes through on their claim to delever a prototype 100MW fusion reactor in 5 years and have them commerciably viable in 10, how would that impact the space program? Ignoring all questions of fusion and assuming it works, it'd revolutionize what could be done in orbit. A nuclear rocket trip to Mars is a matter of weeks instead of months. Most of the solar system would be within relatively easy reach. You could also launch interstellar probes that would report back in a vaguely reasonable timeframe. The main limitation as it stands is energy. Chemical fuel isn't all that efficient and is really heavy. Fusion produces vastly more energy from the same mass of matter, so you'd be able to build spacecraft both larger and faster than anything that could be done with chemical propulsion. Probably want to build ships on the moon and fill them with He3 mined from the surface, as an end goal to really get the most out of fusion spaceships. Avoid all that Earth gravity well poo poo. Of course you would need money for all this, so, welp. It's possible helium and asteroid mining would be financially viable enough to get private companies to go for it. You'd be using a fuckload of fusion reactors on Earth too and they need fuel. I don't know if He3 is so superior to deuterium to make lunar mining worthwhile for Earth reactors though. Processing fuel out of seawater is simpler. At least in theory, fusion powered spacecraft would make the entire solar system readily available to humanity. It'd get rid of probably the biggest technical hurdle, which is the shittiness of chemical rockets. All of the political/economic hurdles would remain. Realistically the first use of a viable fusion reactor is going to be to solve the energy crisis here on Earth, since that pretty much eliminates the energy problem entirely. Grand Fromage fucked around with this message at Feb 21, 2013 around 07:57 |
| # ? Feb 21, 2013 07:54 |
|
|
How do you cool a 100MW reactor in a vacuum? wouldn't you need ridiculous surface area to be able to radiate away that much heat?
|
| # ? Feb 21, 2013 08:11 |
|
|
It requires significant radiators but it's doable. If you want to decrease mass you can go with liquid droplet radiators which are a sheet of circulating liquid metal droplets that radiate heat as they pass through empty space. I imagine there's a big leap from a prototype fusion reactor to a fusion rocket. We can already do fission rockets though.
|
| # ? Feb 21, 2013 08:29 |
|
|
Farmer Crack-rear end posted:I'd be very interested to hear more about this. Trying to get more information but I'm going to assume it'll stay private. They may release some info when they actually do some analysis
|
| # ? Feb 21, 2013 08:44 |
|
|
NASA has been talking to Australian miining engineers this week, two videos in the link, the second one is a bit more interesting. http://www.sbs.com.au/news/article/...mining-frontier
|
| # ? Feb 21, 2013 11:57 |
|
|
More Musky stuff: http://www.huffingtonpost.com/2013/..._n_2727312.html
|
| # ? Feb 21, 2013 13:10 |
|
|
So Planetary Resources want to claim asteroids with beacons. It's an interesting idea but I'm wondering how it could possibly be enforced. Things like UN treaties aside, if you attach something which shouts to the universe "this asteroid is worth a shitload of money", what's to stop someone else from zooming up and stealing it (if we assume this whole process is technically possible in the first place).
|
| # ? Feb 21, 2013 13:51 |
|
|
Nothing in particular. If they ever get that far we're going to have to come up with real laws for it.
|
| # ? Feb 21, 2013 14:01 |
|
|
rolleyes posted:So Planetary Resources want to claim asteroids with beacons. It's an interesting idea but I'm wondering how it could possibly be enforced. Things like UN treaties aside, if you attach something which shouts to the universe "this asteroid is worth a shitload of money", what's to stop someone else from zooming up and stealing it (if we assume this whole process is technically possible in the first place). Lasers, my friend, lasers (or guns, if they want to be lame)
|
| # ? Feb 21, 2013 14:12 |
|
|
I will update the OP launch manifest later but people are telling me that Orbital have abandoned any hope of a March launch for the Antares 110, now they are hoping for a April test launch.
|
| # ? Feb 21, 2013 14:34 |
|
|
peepsalot posted:How do you cool a 100MW reactor in a vacuum? wouldn't you need ridiculous surface area to be able to radiate away that much heat? Well presumably most of that heat energy will be going into your propellant to send it out the back, but as Elukka indicated huge radiators will be critical. rolleyes posted:So Planetary Resources want to claim asteroids with beacons. It's an interesting idea but I'm wondering how it could possibly be enforced. Things like UN treaties aside, if you attach something which shouts to the universe "this asteroid is worth a shitload of money", what's to stop someone else from zooming up and stealing it (if we assume this whole process is technically possible in the first place). Aside from the force of law, nothing. On the other hand what you're doing will be blatantly obvious as you cannot hide in space so enforcing those laws won't be too difficult.
|
| # ? Feb 21, 2013 14:49 |
|
|
Xenoborg posted:Is there a generaly accepted best way to deflect a large asteroid? As they only "space guy" my relatives and coworkers know, they all want to know how we would stop a dinosaur killing asteroid. This is also a good read re: nukes for meteors
|
| # ? Feb 21, 2013 15:18 |
|
|
Zaran posted:I will update the OP launch manifest later but people are telling me that Orbital have abandoned any hope of a March launch for the Antares 110, now they are hoping for a April test launch. This seems to be a theme with Orbital.  I just want to watch a rocket launch from somewhere close to me 
|
| # ? Feb 21, 2013 16:38 |
|
|
Omnicarus posted:Fastest ever achieved was pre-Challenger in 1985, at almost .80 launches a month. That was unbelievably back-breaking according to the grey-beards who worked management in those days. They had originally had a max launch rate of 52 launches a year, with over ~40 being necessary for the recoverable aspects of shuttle to become economically viable. It is worth noting as well, that Challenger lifted off 10 days after Columbia landed in January '86. Had Challenger been sucessful, it's planned landing was on February 3, and the next mission in the chain was for Columbia, launching in early March, so Coulmbia was slated to be turned around in a little under 6 weeks.
|
| # ? Feb 21, 2013 17:04 |
|
|
Elukka posted:It requires significant radiators but it's doable. If you want to decrease mass you can go with liquid droplet radiators which are a sheet of circulating liquid metal droplets that radiate heat as they pass through empty space. Water droplet radiators are the coolest. So is Project Rho, which has a nice blurb about what'd go into making them work. They're much more mass efficient, and the water can be recycled for use in a Whipple shield or purified for crew use. Beer4TheBeerGod posted:Aside from the force of law, nothing. On the other hand what you're doing will be blatantly obvious as you cannot hide in space so enforcing those laws won't be too difficult. Freezing of your terrestrial assets aside, if the defending company has any other mobile resources nearby or mass drivers on large asteroids or the Moon, they might be able to forcibly evict you.
|
| # ? Feb 21, 2013 17:25 |
|
|
|
| # ? May 23, 2013 22:56 |
|
|
So apparently Dennis Tito's new company is making a "major" announcement about a manned mission to Mars next Wednesday. Apparently going to launch in 2018 and will get to Mars and back in 501 days, there's a bit more info here: http://spaceref.com/mars/the-first-...rs-in-2018.html Is this even remotely feasible? As much as I'd love to believe it, 5 years doesn't seem like a lot of lead time for something of this magnitude.
|
| # ? Feb 21, 2013 17:35 |
|
