81–90 of 188 posts
Eventually one of these private space companies will have a highly public, challenger-type disaster. I wonder if a startup like SpaceX could survive something like that.
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It is easy to use superlatives like "safest rocket ever designed". But a lot of stuff can go wrong - fast - when you're sitting on a big pile of potential explosives that under other circumstances you'd keep a safe distance from. Until they actually achieve it, you shouldn't throw the superlatives around. I will be the first to applaud if SpaceX achieves this goal. I am certain that they want to achieve this goal. Bu…
> It is easy to use superlatives like "safest rocket ever designed". But a lot of stuff can go wrong - fast - when you're sitting on a big pile of potential explosives that under other circumstances you'd keep a safe distance from. Until they actually achieve it, you shouldn't throw the superlatives around. This claim revolves more around the fact that the rocket can do a powered abort at any time, I think. It's pure…
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So what you're telling me is that they have a more sophisticated system than previous ones with sophisticated backups. When it comes to reliability sophisticated can go either way - it can be better or can just give more things than can go wrong. For instance what happens on your vertical landing if a sensor malfunction causes the software to decide that the rocket is not vertical unless it is at a 20% tilt? (Don't l…
> So what you're telling me is that they have a more sophisticated system than previous ones with sophisticated backups. Given that the shuttle's SRBs were "once they start, they don't stop until they're empty", sometimes more complicated is a good thing. > Until you have actual experience with the weird stuff that goes wrong in the field, you do not really know what is going to go wrong. And the more complicated the…
Yet even with cars, even with the fact that they have experienced designers, when you build a new car model and put it out, you don't always get it right. You don't know what you did wrong. Which is why we regularly see safety recalls issued on cars - even from the best companies - for everything from software updates to changing the floor mat.
Until you see a model in use in the real world you simply don't know. Even if you have experience on a related model, there is the possibility of something new going wrong. Something you would have never thought of. Like the gas pedal getting stuck on a floor mat.
You take into account everything you know about. You run every feasible test that you think is useful. You run tests in simulators, on isolated components, on the whole model. You review and double review your work. You set up safety checklists to verify everything on the spot. But until you actually see the accident data, you don't really know whether you missed something important.
This is true for cars. It is true for airplanes. It is true for rockets. But the critical differences are that rockets are inherently more dangerous, it isn't feasible to do the same number of tests on them, and we don't get nearly as much accident data.
It is easy to use superlatives like "safest rocket ever designed". But a lot of stuff can go wrong - fast - when you're sitting on a big pile of potential explosives that under other circumstances you'd keep a safe distance from. Until they actually achieve it, you shouldn't throw the superlatives around. I will be the first to applaud if SpaceX achieves this goal. I am certain that they want to achieve this goal. Bu…
First, the Falcon 9 so far has a 100% success rate. The rocket engines are designed to be able to handle having a stainless steel nut pass through the fuel lines without shutting down. More so the vehicle is designed to be able to withstand an engine exploding, even at launch, without damaging the other engines and without preventing the launcher from reaching orbit. And the vehicle has already demonstrated the ability to safely abort on the pad after all the engines have been started.
Second, the launch escape system for the Dragon will be far more capable than anything that's been developed before. Instead of using a separate, heavy solid fueled tractor rocket like Apollo or Soyuz an integrated liquid fueled rocket system will be used. This will provide full escape coverage from the launch pad all the way to orbit, which no manned launcher in history has had. Additionally, the escape rocket will have a high level of redundancy.
Third, the advanced thermal protective system, simple capsule design, and robust drogue and parachute system make atmospheric reentry a lot less risky than, say, the space shuttle or even Soyuz capsules.
Fourth, before a human ever gets in a SpaceX capsule the launch escape system will already have been demonstrated on unmanned launches. By then the confidence in the system should be enormously high.
It's always possible to miscalculate or ignore risk, but SpaceX is doing a tremendous job to increase the reliability of their launcher and to make their manned capsule fundamentally safe by design.
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However, air density is lower the higher you go--allowing for easier acceleration.
This is the big deal with air-launch or dirigible-launch or whatever you call it. The air resistance of the atmosphere is significant. IIRC, it takes 9 km/s of delta-v to get from ground to LEO. LEO is only orbitting at ~7.7 km/s, though, so you can save at least 1 km/s of fuel. As others have said, schemes like Stratolaunch or SpaceShipOne also get horizontal velocity from the mothership.
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Getting upward isn't the problem. It's acquiring the massive horizontal speed required to orbit that is more energy expensive. http://en.wikipedia.org/wiki/Delta-v_budget#Launch.2Flanding
The higher you are, the greater your tangential velocity to the ground. Launching a rocket from the top of Mount Everest vs a beach on the Dead Sea is cheaper in terms of energy required to attain a given altitude.
I would hate to see SpaceX become an acquisition of NASA, or a nationalised company of the US Federal Government. Stranger things have happened, of course, but if Musk wants to retire to Mars, he had best be concerned with this.
By what mechanism, exactly do you think this will happen? He has no plans to sell. He'd like to go to Mars himself, but not if he doesn't think the mission of SpaceX would continue without him. So...that leaves it becoming 'a nationalised company of the US Federal Government"....aka, the gov't takes it over by force? How likely do you really think that is? It only took over Ford because they were bankrupt, so all he…
It is a brave man that gets in to bed with the government thinking he can withstand the intolerable pressure they can bring, if they decide, to bend his will.
Nationalisation...
How likely do you really think that is?
Surely, it is for the oracles to strike a claim on future events, but when you consider gold confiscation in the 1930s, oil nationalisation in the 1950s, the absurd nationalisations of the 1970s, and the crony-saving bail outs of the 'Too Big to Fails' in recent years, it is obvious, I would think, that politicians are happy to corrupt the free market when it benefits their short term interests.
Every time I see something like a rocket or space shuttle launch, I can't help but wonder how much of the weight and cost could be saved using alternative methods . Even helium/hydrogen filled balloons could get them a good chunk of the way there. I know that would be horribly impractical for something the size of the shuttle and it's rocket boosters/fuel tanks, but if a balloon rig can get them to 120,000 ft they ha…
There are companies trying to do that as well. For instance http://en.wikipedia.org/wiki/Orbital_airship describes one where an airship that is part blimp, part fixed wing follows a trajectory where first it is lifted by being lighter than air, then it gets lift from moving fast through thin air, then it gets lift from being near orbital velocity. Theoretically they should be able to get things in orbit very cheaply…
But in space launch, the laws of engineering have tended to be more important. A very reliable reusable rocket is probably going to be a better investment of the marginal dollar than any kind of air launch.
(Unless you are going all the way to things like Stratolaunch, which is riding SpaceX's rocket reliability. The mothership ought to be quite reusable, but building the biggest wing ever in history is going to be a tall engineering order. It remains to be seen which way wins out in the end.)
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The higher you are, the greater your tangential velocity to the ground. Launching a rocket from the top of Mount Everest vs a beach on the Dead Sea is cheaper in terms of energy required to attain a given altitude.
This is almost nothing. The surface of the Earth spins at almost ~450 m/s near the equator and that's being some ~6300 km from the center. Climbing up another 10 km is not going to appreciably change your horizontal velocity.