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It wouldn't have to be used for human flight, it would be used mainly for bulk cargo that you wouldn't mind parting with.
And you all know my opinion of Bob, he'll lash out at any idea that stands between him and MarsDirect.
"Again I remind you, most of the 10% payload penalty is for additional altitude from 185km to 407km. That altitude reduces propellant needed for trans-lunar injection. It's a question of pay-me-now or pay-me-later."
Except that it isnt, alot of that Delta-V you spend is wasted, since such an altitude change requires a disproportionate delta-V charge for circulization-then-escape versus escape only. I am still not convinced either that leaving from any orbital inclination can get you to the Moon with equal efficency. There are definatly launch window concerns versus equitorial orbit too.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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RobertDyck,
John Wickman used nitrogen gas to feed aluminum powder into a test engine; it worked but the Moon doesn't have nitrogen.
Could you use the He3 or waste co2 to push the Aluminum powder into engine chamber.
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Our opinions of Shuttle-C are the heart of our disagreement. I feel it's only engineering, research has already been completed. That permits very rapid development.
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Except that this level of engineering and development can't be accomplished so fast for any reasonable sum, it just can't be done. You are not simply taking the blueprints for the aft quarter of Shuttle and putting a payload faring on top.
And that is to say nothing of the obviously unjustifiable reuseable engine pod, which will take serious work and testing before trusting it to push a $400M rocket and a billion-dollar payload. Again, this is not something that you accomplish so fast.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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If you were to finely divide the Aluminum, and I mean like nanoscale fine, I wonder if it would "flow" like a liquid. If you have ever had the misfortune of having to replenish the toner on a modern copier machine, that black powder is so fine that it will run almost like a fluid. Nanoscale aluminum would be a better propellant too with its far larger surface area.
How to make it? Liquify the metal and spray it under the appropriate pressure in a vacuum, and let it settle out. Recycle the "spraying" gas for the next batch if you need something to pump and cool it with.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Not unjustifiable, completion of ISS will take 3 launches with the same pod. Then the LTV will take another. At $120 million per launch it's a lot less expensive than other launch systems. You could test parafoil and landing by air drop from NASA's B-52B. Yes, that means re-activating this venerable bird. The army http://www.almc.army.mil/alog/issues/Ja … htm]Guided parafoil air delivery system-heavy GPADS-Heavy already has the capability needed for the engine pod.
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Oh but it is, for one very simple reason: It doesn't save much money. You have to compare the cost of developing, handling, and reintegrating versus the cost of a pair of cheap RS-68's and cheap Delta-II class upper stage for a kick stage.
Since its going to cost around a billion dollars at the minimum to design, build, and test your engine pod and very likly ten or twenty millions of dollars for each recovery/reprocessing, you just aren't saving that much money. This is a brand new fully independant space reentry vehicle, easily about as complex as the CEV space capsule if you include the complexity of the engines. This level of engineering, to risk tens of billions of dollars of payload (over the life of the design) to your pod just Does Not Come Cheap. The RS-68 and Delta-II on the other hand, are proven reliable technology designed for just this role, expendable rockets. I don't think that you are aware of the level of the game you are wanting to play in Robert, this is way beyond anything you have ever had any experience with I bet.
We're talking only about $40M of stuff here, if your pod saves half that, then you will need to fly fifty times to save any money at all. Even if it costs half a billion to develop (a fraction of even X-38), and half that to reuse (~$10M each), you will still need to fly about twenty times to save much money.
But the cost isn't just monetary, using the engine pod scheme you are introducing signifigant risk to the Shuttle-C development, which is why its supposed to be better then clean-sheet in the first place. If the pod can't be built as easily as you want, you will incur substantial delay to Shuttle-C while it is fixed or dropped in favor of RS-68, and besides the schedule disaster that would cause, it would substantially affect the price of Shuttle-C too.
And if you lose the thing? Or if its damaged on reentry and nobody notices, destroying the payload? And you'll miss the Mars launch window for another two years? The cost of building a second pod? Its Just Not Worth It. Period.
And speaking of development, if we go and rush to the side-mount Shuttle-C with your pod, but then switch to all-expendable inline SDV, then your engine pod becomes worthless. All that work would be for nothing along with the rest of Shuttle-C, since the launch pad can only accomodate one rocket or the other.
Have you noticed that all of your schemes revolve around employing lots of antique NASA hardware? Refurbishing costs money, its not free either, nor is the cost of hiring all the engineers to execute your plans with hardware that requires too much manpower to operate... The SSME imparticularly is notorious for this.
Your plan is just a bad one, thats all there is to it
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Back to something I haven't flogged in a few months, RSRM refurbishment and improving the 85/15 fuel to dry mass ratio. A 4 segment SRB weighs 192,000 pounds without fuel, meaning 240,000 for a 5 segment. Improving that 85/15 ratio whould yield significant performance gains.
Thiokol claims it saves money by fishing the RSRM out of the ocean and rebulding them. Okay, go with that for the 4 segment at the 85/15 ratio.
But, if we go with a five segment stick, then do some trade studies to see whether a throwaway 5 segment at 90/10 gets more mass to LEO at a lower cost.
Materials technology has improved substantially since the RSRM was first designed way back in the 1970s and to go 90/10 on a five segment throwaway stick would add 80,000 pounds of payload to your second stage!
Naturally, this would be for cargo only until plenty of experience had been acquired but we are approaching 1/2 of shuttle C payload with a single stick.
It seems to me that a 90/10 SRB on shuttle C might not help if total payload mass exceeded side mount capability for other reasons.
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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I do not accept your development cost estimate. The engines do not have to be removed and refurbished between every flight, according to an astronaut who is an engineer. The bottom line is we don't have to convince each other, we have to convince Mike Griffin.
Oh, one strong point in my favour: your scheme doesn't have any way to accelerate ISS construction. Mine does. I strongly believe in getting it done quickly, move on to the Moon and Mars.
::Edit:: I really don't like Ares becaue it requires too much development. However, although the upper stage and cargo are axial mounted, the main engines are still a side-mount pod. That means no modification to the launch facilities.
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Shuttle C would have to have auto-docking capbility, and be met with a Shuttle already in orbit to complete construction.
NASA does not have the proven technology for auto-docking (DART was the most recent test, didn't pan out). Having to send a Shuttle up and a Shuttle C might over-tax ground control capability. Plus, where would the Shuttle or Shuttle C go if either one is docked with ISS at the same time? (you need Shuttle for people to build and Shuttle C for the construction equipment).
You would also have to take time to test and vet Shuttle C prior to placing any of the ISS modules on it (you lose them, and you lose ISS... more or less). That will take time because we have to prove to the international partners that their modules will be safe.
Your time line is aggressive and overly optimistic, I applaude you, but optimism is not a good basis for rational planning.
Stop arguing over the costs GCN, it gets you no where. There are enough reasons based on mission complexity that make Shuttle C for ISS construction nearly impossible.
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So either barter for the technology from the russians progress or from the ESA ATV cargo ship. But lets do something that works...
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Shuttle-C for ISS construction does not have to dock with ISS. It just has to rendezvous and stabilize the cargo. The orbiter would move over to Shuttle-C, pick off one piece, carry that to ISS for installation, repeat. After all components are gone, the engine pod would de-orbit for landing at the Salt Flats.
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I do not accept your development cost estimate. The engines do not have to be removed and refurbished between every flight, according to an astronaut who is an engineer. The bottom line is we don't have to convince each other, we have to convince Mike Griffin.
Oh, one strong point in my favour: your scheme doesn't have any way to accelerate ISS construction. Mine does. I strongly believe in getting it done quickly, move on to the Moon and Mars.
::Edit:: I really don't like Ares becaue it requires too much development. However, although the upper stage and cargo are axial mounted, the main engines are still a side-mount pod. That means no modification to the launch facilities.
Oh really? Why not? The ESA ATV, which is a comparatively complex vehicle, cost about a billion dollars to develop in today's money. So would the X-38, which was really just a reentry vehicle like you want, except with a plastic chaimber for people and stubby winglets. The CEV capsule unmanned testbed, the one supposed to fly by 2008 or something, is budgetd to cost several hundreds of millions of dollars if memory serves, and that will be quite a bit less complex then your engine pod. I think that it is fair to place the onus on you, Robert, to produce even marginally relevent proof that your engine pod won't cost about a billion dollars.
I don't think you understand just how complicated that real-world aerospace engineering is to trust billions and billions of dollars to Robert, this is the gulf that sets apart the sad little AltSpace companies and the "evil big corperations."
The SSME engines do indeed have to be removed and inspected, refurbishing is a much more in-depth procedure. In any event, because your pod will NOT be making a gentle runway landing like Shuttle, they will have to be pulled and checked anyway, NASA will have a hard time affording losing your pod and its payload.
Your way doesn't have any way to accelerate the ISS either, because its going to take at least two years or so to build Shuttle-C, and about a year after that to test-launcha few times before trusting an ISS payload to it. (See Delta-IV HLV testing, and that was comparitively easy) By that time, having Shuttle-C won't accelerate construction signifigantly.
I think that its unrealistic to build Shuttle-Z, that the problems of side-mounting such a large pod and the inherint performance penalties make Ares/Magnum the obvious choice. An inline design is called for in both MarsDirect and NASA DRM and is the "heavy" option presented by Thiokol, not Shuttle-Z.
Edit: Oh, and AltSpace companies performing the work for hundreds of millions of dollars less on your engine pod don't count, since they are not competant nor reliable.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Okay, all of which requires test runs using the Shuttle in mock exercises prior to actual use of Shuttle C.
If Shuttle C fails to stabilize, or the Shuttle fails to make the rendezvous, you lose the ISS cargo. I would also imagine that doing this maneuvering would take fuel- how much? Can the Shuttle make that many orbital corrections?
If the Shuttle is picking up these pieces, would it put it in the cargo bay? Wouldn’t it need the shuttle arm to catch the pieces? If so, is there room for the shuttle arm and the cargo?
All of these questions (and more) need to be answered before we can attempt the process you outline Robert. All of that takes time, which ends up costing us more money and diverting us from moving beyond LEO.
Even if we built Shuttle C in a small time frame, it would take several dry test runs before we can confidently claim to be ready for actual Shuttle C use- that *will* take years. It is time we can ill afford.
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If we were willing to practice, then fabricating 2 spare ISS trusses and sending up two trusses on the very first shuttle C test shot might be a low risk experiment.
In "aerospace" terms these trusses cannot be astronomically expensive and therefore are the ISS paylaod we can most afford to lose.
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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Can we afford to lose one of the three remaining Shuttles on this test?
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(Edit: the trusses....)
But they'd take time to build.
And I do not think the trusses are that simple, either. Probably loaded with sensors, data-boxes etc etc.
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Not a real truss but most likely a dummy payload only mass and size.
Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars
edit another link:
Detailing the Science of Man on Mars
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Regarding low-energy access to the Earth-moon L1 point: there is no low-energy access. In fact, it probably takes slightly more energy to go to L1 from low Earth orbit and stay there than it does to escape the Earth. L1 "orbits" the earth at about 2,000 mph/3,000 kmph. If one flies through it, one can't stay at it. It may be possible to fly to the moon, use lunar gravity to boost one into an orbit that oscillates between the moon and L1, then two weeks later when one is flying through L1 perform a small delta-v to stay there. L1 and the moon orbit the Earth at essentially the same speed. Going to L1 from Earth takes, I think, an extra 300 or 600 meters per second compared to escape velocity (but I don't remember where I saw the figure).
Weak stability boundaries connect EML1 to the other EM lagrange points and the Earth-Sun Lagrange points. For a low delta-v one can move among those points (though the travel time is usually months at minimum). But to go to the Mars-Sun lagrange points requires about the same amount of delta-v as traveling between the planets normally takes.
-- RobS
I have located an AIAA paper that asserts that lunar encounters (fly-bys) do lower the total delta v needed for travel from LEO to EML1.
As alwasy, its time versus fuel.
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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From This: 'Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars'
1.2. Assumptions
Assume that there will be a series of robotic missions to Mars, of as yet unknown character and timing, that will be capable of carrying out investigations and measurements, and doing technology/infrastructure demonstrations.
The human site will have been certified for landing safety with data from robotic missions before the humans land.
1C. Determine if each martian site to be visited by humans is free, to within acceptable risk standards, of replicating biohazards which may have adverse effects on humans and other terrestrial species. Sampling into the subsurface for this investigation must extend to the maximum depth to which the human mission may come into contact with uncontained martian material.
If I understand that correctly, they want robots to go and look for life and characterise the life to the maximum extent that humans will do the same. Its like certifying the research as safe so that humans can repeat the same or less research and rubber stamp it.
Sounds like someone is selling robots..
Come on to the Future
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Well that is the current process in which we are schedueled to send them every 2 years to the surface until sometime in 2030 before deciding that we can go.
From the Objective A. section:
Obtain knowledge of Mars sufficient to design and implement a human mission with acceptable cost, risk and performance.
There are only minimal missions to mars that can answer the risk to a crew all others have only scientific value.
None will calculate acceptable costs and or performance.
Of which most missions will cost 500million to 1 billion each to answer scientific curiosity.
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From This: 'Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars'
1.2. Assumptions
Assume that there will be a series of robotic missions to Mars, of as yet unknown character and timing, that will be capable of carrying out investigations and measurements, and doing technology/infrastructure demonstrations.
The human site will have been certified for landing safety with data from robotic missions before the humans land.
1C. Determine if each martian site to be visited by humans is free, to within acceptable risk standards, of replicating biohazards which may have adverse effects on humans and other terrestrial species. Sampling into the subsurface for this investigation must extend to the maximum depth to which the human mission may come into contact with uncontained martian material.
If I understand that correctly, they want robots to go and look for life and characterise the life to the maximum extent that humans will do the same. Its like certifying the research as safe so that humans can repeat the same or less research and rubber stamp it.
Sounds like someone is selling robots...
Whaaat? This is insane, somebody is trying to sell robots. Look, whatever happend to NASA being willing to take a little risk? The threat of "Martian Bugs" is not far off from worrying about the sky falling. There is no way a robot could probobly test for human incompatibility anyway, so what is the use? Do we make sure humans just stay away from the scarry bugs that we are supposed to be hunting for?
The robot that would possibly hunt for life on Mars would be quite expensive and very well could fail; if there is Martian life then it is probobly underground and not on the parched, UV-blanched, mildly corrosive surface. I've got serious doubts that a robot drill rig will be effective.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Bump topic discovery that needs to be fixed
page 1 is done
Page 2 final done
page 3 & 4 fixed 12-28-20 with auto repair done after fixing post 166
Last edited by SpaceNut (2018-12-16 19:53:20)
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