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Old August 23 2013, 09:47 PM   #46
sojourner
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Re: Mars One - Unethical?

Now your just cherry picking quotes and making shit up. Elon has already stated that he has no real plans to develop hyperloop and just basically put the idea out there for other people to run with. Also, as with Tesla, if he did start that project no funds from it would cross to SpaceX.
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Old August 23 2013, 10:04 PM   #47
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Re: Mars One - Unethical?

I'm cherry picking nothing. If you think Ed Kyle doesn't know what he is talking about, and the pro-SLS folks there, then argue with them.
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Old August 23 2013, 10:15 PM   #48
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Re: Mars One - Unethical?

Nah, there are much more knowledgeable folks there than me arguing that stance, and doing a good job at it.
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Old August 23 2013, 10:23 PM   #49
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Re: Mars One - Unethical?

The opinion poll there at nasaspaceflight has more for than against. Lots of bright folks in the industry on both sides of that one. I'm just not trying to put them out of work.

Besides, its ULA that is the biggest threat to Musk. I never did believe it was range safety that was the real reason Musk was run off the coast, did you?
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Old August 23 2013, 10:31 PM   #50
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Re: Mars One - Unethical?

"run off the coast"? Are you talking about delays on one of the F-9 launches due to rockets on other pads? Or is this something about the proposed Texas launch site? (which I haven't had any interest in and don't keep up on)
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Old August 23 2013, 11:34 PM   #51
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Re: Mars One - Unethical?

He didn't want to launch off a tropical island you know: http://en.wikipedia.org/wiki/SpaceX_launch_facilities
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Old August 23 2013, 11:45 PM   #52
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Re: Mars One - Unethical?

publiusr wrote: View Post
gturner wrote: View Post

That's the low cost estimate - from the NASA guy who's trying to sell the SLS program.
Any new LV is going to cost out the wazoo up front. Imagine if Venture Star or some other RLV were on the table--I guarantee you it would be even more costly--and with less payload to boot. Compared to F-35 and other things this gov't does, it's a bargain.
But we're not getting a reusable launch vehicle, where the insanely high upfront cost gets paid down by a high flight rate. We're getting an expendable rocket with an insanely high upfront cost and an insanely high unit cost, so we won't launch it very often at all.

The Falcon 9 v1.1 can deliver payloads at about $1,800 a pound to LEO, and the Falcon Heavy target is about $1,000 a pound. If they manage to get re-usability working that should drop to about $200 a pound.

The best case scenario for the SLS is about $7,000 a pound, and it's more likely to come in over $10,000 a pound, with a high-end estimate of $50,000 a pound.

gturner wrote: View Post
Even if you advocate for heavy lift, it needs to be cheaper, and it shouldn't be wasting precious payload and stack height on a big crew module.
I don't know why you are concerned so much about stack height. It worked perfectly well for Saturn, and will work perfectly well for SLS.
Here's a Saturn V rollout.



The Saturn V is 363 feet tall, and the launch tower clears the top of the VAB door by about six feet. The SLS Block II crew version is already 385 feet tall, and there's no big payload bay underneath the crew module, either. That's probably why they're not developing any payloads (like a lunar lander) for it. There's no place to put one.

The screw-up was that they picked a fuel that's not dense, and thus doesn't have much impulse per volume, and then picked a narrow tank diameter (8.4 meters) so that the first and second stages necessarily have to be really, really tall. Then they mandated a very, very tall launch escape tower to sit on top of their capsule. And then it's pretty much done, already scraping the paint on the roof of the building. It'll work, as long as you don't mind limiting your missions to joy rides.
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Old August 24 2013, 12:07 AM   #53
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Re: Mars One - Unethical?

publiusr wrote: View Post
He didn't want to launch off a tropical island you know: http://en.wikipedia.org/wiki/SpaceX_launch_facilities
Oh yeah, that old problem.
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Old August 24 2013, 10:40 AM   #54
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Re: Mars One - Unethical?

Deckerd wrote: View Post
I don't think growing food would be a problem. Yes the sun is further away but it's still bright enough to grow food in a sufficiently modified botanical environment. If you can still harness the power of the sun, you can grow food for free, once the environment has been created. Once the startup water for this system has been installed, it can be recycled indefinitely, for both humans and plants. The beauty of water is that if it's kept inside a sealed environment, it never changes and can be filtered repeatedly. The biggest problems for humans would be physiological (managing illness and ageing) and psychological (living in a container for the duration of life; keeping motivated; living with regret and loss).
This is for course true, but quite temporary. The problem is that all the equipment would eventually break, the habitat will be slowly damaged by the environment, the air will leak and the water will escape slowly from their sealed containers. On top of that, the population will probably grow and you will need to expand your settlement. So, as time passes you would need to fix things, replace things, locate and mine local resources, create local factories, and so on. You would desperately need laboratories to create medicine, because the ones that you brought from Earth will be spent quickly. To make matters worse, the raw materials and their availability on Mars would differ, so you might even need to make an invention or two along the way.

That's hard even on Earth. No country is fully independent, everyone depends on imports of technology, medicine, raw resources or something. Our life would be severely affected if anyone ceased all imports at once, and some are struggling with no limits on them. Mars, which is much more unwelcoming and remote than any point on Earth, would be much much harder.

Bootstrapping an independent civilization that can support itself and build everything for itself is something we can't do down here yet. Building one factory for one small subset of what we need is difficult, starting anew is a whole new challenge that will be enormous even if you built only the most important and used technology from the past that's easier to build there.

On the other hand, Mars will be an amazing learning experience in that regard that might help us learn how to deal with such problems, even down here. So we should definitely do it.
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Old August 24 2013, 05:14 PM   #55
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Re: Mars One - Unethical?

gturner wrote: View Post
The screw-up was that they picked a fuel that's not dense, and thus doesn't have much impulse per volume, and then picked a narrow tank diameter (8.4 meters)
That isn't exactly a screw up--you can't beat LH2 as a fuel. and 8.4 isn't as narrow as Falcon heavt, the EELVs, etc. Delta IV is the narrow beastie. But if you will recall, Ares V was going to be a 10 meter core, before the folks pushing ULA's agenda got it killed. Still, there is nothing wrong with a tall LV, and two DIRECT-ish Block IA Block II launches will allow for a lunar return--if it is supported.

Now frankly, if I had my druthers, I would push for something like Nexus or AMLLV--but that's not going to happen anytime soon. I'll take what I can get.

Now I think you might have called for wider LVs (that wouldn't fit in the VAB at any rate.

Here is a diagram showing how many RL-10s it would take to do the job of the original five F-1s
http://blogs.nasa.gov/J2X/wp-content...8/cluster3.jpg

http://blogs.nasa.gov/J2X/2013/08/06...rs-25-vs-j-2x/

Now I don't think you want to try that with balloon tank construction.

Now I actually don't have a problem with wide vehicles, but that would cost a lot more than SLS right now--and may wind up being a global project. A global-lifter would be something to be planned out 50-100 years from now, with each nation pitching in.

I have this notion of a ring station made all in one piece but serving as a wet stage LOX tank near the base of a vehicle on ascent, with a superlightweight high volume hydrogen bullet nose that would be discarded, leaving the more sturdy ring tankage with spokes and all pre-built as a wet stage. This might be a cycler in its own right.
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Old August 24 2013, 09:55 PM   #56
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Re: Mars One - Unethical?

publiusr wrote: View Post
gturner wrote: View Post
The screw-up was that they picked a fuel that's not dense, and thus doesn't have much impulse per volume, and then picked a narrow tank diameter (8.4 meters)
That isn't exactly a screw up--you can't beat LH2 as a fuel. and 8.4 isn't as narrow as Falcon heavt, the EELVs, etc. Delta IV is the narrow beastie. But if you will recall, Ares V was going to be a 10 meter core, before the folks pushing ULA's agenda got it killed.
The Falcon doesn't have to use a large diameter core because it uses a fuel and oxidizer combination that is three times denser than LH2/LOX. An 4.8 meter diameter RP-1/LOX tank can store the same propellant mass as an 8.4 meter LH2/LOX tank of the same height. If you adjust for volumetric specific impulse, RP-1/LOX takes less than half the volume as LH2/LOX for the same delivered impulse.

Still, there is nothing wrong with a tall LV, and two DIRECT-ish Block IA Block II launches will allow for a lunar return--if it is supported.
There is if your rocket is scraping the roof of your building before you've added that little thing called a "useful payload." NASA looked at adding a third stage configuration to the SLS but it wouldn't fit inside the building.

Now I think you might have called for wider LVs (that wouldn't fit in the VAB at any rate.
You do realize that the Space Shuttle had really big wings and a tail, don't you? It was about 24 meters in either dimension on rollout, and they didn't have to saw it in pieces to get it out the door or anything.

Here is a diagram showing how many RL-10s it would take to do the job of the original five F-1s
http://blogs.nasa.gov/J2X/wp-content...8/cluster3.jpg

http://blogs.nasa.gov/J2X/2013/08/06...rs-25-vs-j-2x/

Now I don't think you want to try that with balloon tank construction.
Why on Earth would anyone but NASA think of using RL-10's on a big vehicle? They're the most expensive engines in terms of $ per thrust ($1,500 per lbf). Even the SSME comes in at about $120 per lbf. An SRB, the F-1, the RS-68, and the Merlin 1-D are in the $14 to $20 range per lbf. A two-stage all RS-25 version of an SLS (about 9 million lbsf at liftoff) would cost about $1.3 billion just for the engines - which are thrown away.

Now I actually don't have a problem with wide vehicles, but that would cost a lot more than SLS right now--and may wind up being a global project. A global-lifter would be something to be planned out 50-100 years from now, with each nation pitching in.
Well, I can see how the SLS's projected launch rate would get you to think in 100-year time frames, but to the rest of us that's like someone in the mid-1800's trying to figure out how to get a paddle-wheel steamer to the moon.

First unmanned test flight of the Saturn V: 1967.
Last lunar landing: 1972.
First planned manned flight of the SLS: 2021?
First planned flight using an engine that's not left over from the Space Shuttle: 2027.

NASA plans to fly one mission per year, with one year being a cargo launch and the other year being a manned launch, with the evolved 130 tonne capability first flying in 2032. People who weren't even born when Obama and Holder canceled Constellation in 2009 will be working as engineers on that mission, employed by managers who weren't born when Bush announced the Constellation program.

I imagine they'll go for a moon landing sometime between 2036 and 2040, which, from the commencement of the program, is the same span as from the attack on Pearl Harbor to Neil Armstrong setting foot on the moon, but without actually inventing a single new engine, much less having to invent jet engines, supersonic flight, rocket engines, staged missiles, and, well, the same freakin' engines they're planning on using for the boosters in the 2030's.

It's called bloat and technological stagnation. Some people cheer it on.
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Old August 29 2013, 11:15 PM   #57
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Re: Mars One - Unethical?

gturner wrote: View Post


The Falcon doesn't have to use a large diameter core because it uses a fuel and oxidizer combination that is three times denser than LH2/LOX.
That isn't a plus for BEO, or depots actually. I want a wider core for its own sake in that is is less cramped. One of the reasons Webb is so complecated is due to Falcon/D-IV H shrouds. ATLAST is a much simpler architecture. And its visible light too, where Webb really isn't, but that's another fight. http://en.wikipedia.org/wiki/ATLAST


gturner wrote: View Post
It's called bloat and technological stagnation. Some people cheer it on.

I don't call tried and true stagnation. Rather, its things like Venture Star that try too much that should worry us.

Now (towards the last) this book actually calls for both HLLVs (BEO station construction, etc.) and RLVs (frequent flights, crew exchange):

http://www.amazon.com/Spaceflight-Ae.../dp/0894640461

The thing about depots is that leaking fluids can cause quite a mess:

http://www.nasaspaceflight.com/2013/...investigation/
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Old August 30 2013, 12:27 AM   #58
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Re: Mars One - Unethical?

publiusr wrote: View Post

The thing about depots is that leaking fluids can cause quite a mess:

http://www.nasaspaceflight.com/2013/...investigation/
Well then it's a good thing fuel depots don't need life support ventilation systems.
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Old August 30 2013, 10:42 PM   #59
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Re: Mars One - Unethical?

Sigh--I'm talking about dealing with liquids in zero gravity and how very hard they are to deal with. Ever heard of ullage rockets? Guess why they are used--to help seat propellants because, when not underway, they tend to form blobs:

http://en.wikipedia.org/wiki/Ullage_motor


http://www.parabolicarc.com/2011/11/...lift-vehicles/
Michael Gazarik, NASA’s space technology program director, says that CPST and the Space Launch System (SLS) heavy-lift rocket currently under development are complementary technologies. “To explore deep space we need a heavy-lift vehicle — SLS...

http://www.spacesafetymagazine.com/2...t-fuel-depots/

Patrick R. Chai and Alan W. Wilhite of the Georgia Institute of Technology presented a study earlier this year estimating that depot tanks would lose about $12 million worth of propellant per month in low Earth orbit ...

Now I don't mind cryoogenics like some do--but I'd prefer to deal with them in as few large segments as possible to eliminate boil off. As it stands, it is expected for SLS itself to launch a depot with enough active cooling an volume to make LH2 handling worthwhile--something Musk has not demonstrated.
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Old August 31 2013, 12:47 AM   #60
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Re: Mars One - Unethical?

The rest of your quote is:

Patrick R. Chai and Alan W. Wilhite of the Georgia Institute of Technology presented a study earlier this year estimating that depot tanks would lose about $12 million worth of propellant per month in low Earth orbit if protected only with passive insulation.

I don't think anyone has ever suggested storing liquid hydrogen in a passively insulated tank in low orbit.

ETA: It goes on to say:

The cost savings could be leveraged to other initiatives, such as developing a lunar lander or a nuclear propulsion module, both of which –in theory- would be unfunded with the SLS option

They're not unfunded in theory, they're unfunded in the NASA budget. Without some kind of payload <voice deep and resonant with lots of reverb> "exploring deep space" </voice> is the same as sitting in LEO, but with vastly more radiation and no view. NASA is talking about sending the Orion on a trip around the moon, but what is the point of that? We've already flown around the moon thousands of times. With no lander, there's no purpose to flying around the moon, except that the purpose of flying around the moon is to justify burning all the fuel for the SLS without a lander and with nowhere in particular to go.

Last edited by gturner; August 31 2013 at 01:01 AM.
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