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Ok, shall we leave the rocket issue to one side for a while.
Next difficult one: energy source. Solar or nuclear. I think those are the only two options, unless there's some way of operating hydro on the Moon.
Anyway, I would certainly opt for solar. The arguments are more balanced for a Mars Mission, but with the moon being so close, I think there is little to be gained from nuclear.
We can start with Mars Rover style panels if we wish. They give something like 100 watt hours I think. But we can probably triple that on the moon.
But of course we have lunar day and night, so we have to have storage.
Suggest we start with chemical batteries for storage.
Would there be an argument for an in-out mission to begin with? So we set up some energy storage process but then evacuate the humans, only returning to take up permanent occupation once the energy stored is sufficient to cope with lunar nights.?
What methods of energy storage are practical on the moon?
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Don't forget the peaks of eternal light. A moon mission would be best situated at the poles, where there is plentiful Sunlight (for crops and power), and (possible) water in the craters.
Use what is abundant and build to last
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This is , I think, why nuclear is better than solar. Nuclear doesn't need storage, and it is hard to store enough power for two weeks. What exactly do you dislike about nuclear/like about solar, louis?
-Josh
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Terraformer -
Yes I did momentarily discount the peaks of eternal light, or maybe the sceptic in me was wondering about those.
Have they been proved to exist definitively and if they have been, do they make suitable locations for a base (or is there a good location close by)? Generally speaking I always feel a nice bit of flat land is best for first base.
Jump -
No - nuclear does require storage as well, otherwise if the nuclear system fails you have nothing to fall back on. Of course you can take along two nuclear generators, in which case the chances of both failing are pretty slim, although if they require monitoring by a specialist engineer then injury to or death of the engineer could be problematic (but less so on the moon, compared with Mars).
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SSTO is very difficult with LH2/LOX engines, but is possible. VentureStar proved it. But it would be easier with newer technology. NASA is slowly working on SCRAMjet engines and a hypersonic airframe.
X-43A flew at mach 9.8, just short of mach 10. They air-dropped a Pegasus rocket from a B-25 aircraft; the aircraft flew at subsonic speed, the rocket flew to mach 5. They intended to test first with the rocket to mach 7, then X-43A would separate and sustain mach 7. Unfortunately the Pegasus proved unable to handle that much speed within the atmosphere. The rocket's tail fins ripped off. The second test was supposed to fly the rocket to mach 5, then X-43A would separate and accelerate to mach 7. They proceeded with that second test without duplicating the first; it worked. Unfortunately, although the first test included a parachute so they could recover the X-43A, when the rocket went out of control the range safety officer detonated it without attempting to first separate the aircraft. The X-43A was destroyed by the rocket's auto-destruct. For the second test they flew over water and didn't even load a parachute on-board, they didn't even try to recover it. Although the test was perfectly successful, they lost the second aircraft. The third and final test flew the rocket to mach 5, then the aircraft separated and flew to mach 9.8; again a success, but again without a parachute. They initially only built 2 X-43A aircraft, they actually had to build a third for the last test. But that third and final aircraft was lost in the test as well.
ATK is the company that builds SRBs for the shuttle, as well as bullets, missiles, and torpedoes for the military. They have the contract from NASA to further develop SCRAMjet and hypersonic technology to at least mach 20. The space shuttle re-enters the atmosphere at mach 25, so if you could leave the atmosphere at that speed you would coast to an apogee equal to orbital altitude, only requiring a small push from the OMS to circularize orbit. Mach 25 may not work, but mach 20 using an air-breathing engine would dramatically reduce the need for rocket propellant. Most of the weight of LH2/LOX propellant is LOX, so an engine that uses atmospheric oxygen would dramatically reduce its fuel tank. The military already contracted ATK to develop a mach 5 missile that uses hydrocarbon fuel (JP-10 jet fuel), it uses a solid rocket to accelerate from a ship to mach 4 before the SCRAMjet ignites. Boeing is working on missile to fly at mach 7 using JP-7 jet fuel, also using a solid rocket to mach 4. This demonstrates hypersonic combustion with hydrocarbon fuel. The military wanted a supersonic combustion turbine engine, which would permit a jet to take off from a runway on its own power and accelerate to mach 6. Congress cut funding for that. But such a hydrocarbon fuelled turbine engine could accelerate an SSTO to sufficient speed to ignite a LH2 fuelled SCRAMjet, which would fly to something greater than mach 20. Then a LOX/LH2 rocket would push into orbit. Better yet, configure the LH2 SCRAMjet engine to be a Rocket Based Combined Cycle (RBCC) engine, which starts as SCRAMjet, converts to air/LOX mix, then to pure rocket. That would permit just two engines: turbine and RBCC. If fuel tanks are internal, the RBCC main engine can be used for orbital manoeuvres as well, eliminating the need for a separate OMS. During re-entry the hydrocarbon fuelled turbine engine could air-start after slowing to subsonic speed, permitting powered landing.
Now THAT would be the ultimate SSTO: a true spaceplane. And technology is currently under development, although being developed for the military to make better missiles.
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Thanks for the quick tutorial Robert. I'm very much a beginner in this area.
I think I've read that the difficulty with jet engines at speed is the heat - when you are getting to these high Mach speeds the air is so superheated it's behaving quite differently form at lower temps. But certainly longer term, the space plane concept sounds good.
My interest is still in a pure rocket engine achieving SSTO.
Are you saying that at present there is no way you could get a 10 tonne payload to LEO on a single stage reusable craft? If so, can you explain why.
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It's not impossible, VentureStar could do it if you stuck with solid wall composite cryogenic propellant tanks. But you have to use the newest, latest, state-of-the-art of everything.
It doesn't actually require anything new, but the entire culture of NASA and their contractors have become so afraid of anything new that they claim anything that hasn't already been done, can't be done. NASA was a "can do" agency in the 1960s, they appear to have lost that. It isn't all NASA's fault, their contractors use every excuse they can to gouge NASA for more money. And congress has been afraid of every little set-back, even before Mercury. Congress was convinced to stay out of the way due to the race for the Moon, but that was an extension of the cold war. Congress wanted to cancel the Moon program after Apollo 1. It was significantly delayed. Without the impending doom of loosing allies to a rival superpower, congress has no stomach for any tiny failure. And new development will always have failure. Add to that NASA has to struggle between military contractors who provide their largest hardware who don't see space exploration as having any value, only make-work project and cash cow, verses congress who always wants to cut NASA's budget. So the shuttle did not get safety features that NASA knew from the beginning were necessary. The accidents were only a matter of time, they was destined to happen.
The reason I say all of this, is many people felt VentureStar was too much of a leap forward. It had too many new features. But the truth is the lifting body was developed and well characterized by NASA in the late 1960s and early 1970s, conformant fuel tanks have been used on aircraft for decades, composite cryogenic fuel tanks were demonstrated on DC-XA, the heat shield was the same material as the current shuttle, aerospike engines were a consideration for the original shuttle and tested on a SR-71 Blackbird in preparation for X-33, and rapid turn-around procedures have been in use by the airline industry for years. Each piece of VentureStar was demonstrated already, the pieces just were never brought together before. So I am quite critical of those who claim VentureStar was too great an engineering leap.
As for those who want a Two Stage To Orbit shuttle, I have to point out our current shuttle was supposed to be that. The 1968 specifications called for a lifting body orbiter lifted by a delta wing and fuselage booster. Both piloted, and the booster would not have a heat shield since it would actually leave the atmosphere. That was scaled back to what we have so president Richard Nixon could redirect funds to the Vietnam War.
I could give a list of things that were developed but never flown. Technologies that were ready in the late 1960s or early 1970s many people today think are too advanced to build today. I was a kid in the 1960s, I find the current attitude toward space frustrating.
But yea, VentureStar could just barely do what you want to do.
Oh! Delta Clipper eXperimental (DC-X) was another attempt to do what you want, taking a completely different approach. DC-X, and the later DC-XA (for Advanced) was a land-on-your-tail rocket. Still had a heat shield for atmospheric entry, but with retractable legs and the demonstration model did land in its tail several times. Unfortunately during the last test flight of DC-XA a worker left a safety pin in one of the landing legs, so it could retract but not re-deploy. It flew, it worked perfectly, it landed but only 3 of its 4 legs deployed so it fell over on its side. When it hit the ground its hydrogen fuel tank split open completely, spilling fuel over the tarmac. It burned, completely destroyed. It was developed by the Air Force under a project by Senator Graham, then after successfully demonstrating it works it was handed over to NASA. They upgraded the fuel tanks to carbon fibre epoxy composite for liquid hydrogen, lithium aluminum alloy for liquid oxygen. After the upgrade DC-X was renamed DC-XA. It worked, but the first flight after the upgrade it crashed and burned. It was never rebuilt. It was never my idea of a space shuttle, it makes far too much use of propellant for landing, but it was a low cost alternative to the current shuttle. Another of several low cost alternatives that were lost forever. Conspiracy theories can start here.
But again, what you want can be done, it's just hard and requires the latest state-of-the-art of everything.
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given that we're being a bit speculative here:
In the event that a small fusion reactor become possible with a power output of several megawatts (The Polywell for example), would a type of SSTO Ramjet Ship be possible?
Atmosphere air would be superheated into a dense magnetically confined plasma that is expelled out the back. More air would be fed through the front of the 'engines' from ramming through the atmosphere. The air maybe heated by lasers, or an electric current or whatever works...
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So basically a fusion NTR.
There *is* and SSTO thread for all this, by the way.
Leaving the rocket issue behind for the second time, back to power generation. I'm in favour of Solar, mainly to get all the No-Nuke types to shut up. Anyone suggesting we launch a nuclear reactor into space would be commiting political suicide, even if the reactor had no fuel in, and he fuel went up seperately. Which would require someone to fuel the reactor, meaning one or two less people out of the crew.
How long would this mission last? While we aren't bound by return windows, we want to get a suitable amount of exploration done. Knowing how long would mean the difference between taking all our food with us and growing it there.
Which brings me to the most important question: Why are we going? Are we going to explore the moon (like Apollo) or are we going to set up a colony? That influences the equipment we bring along and how long we stay. If the ideas to set up a colony, we'd ned to be able to manufacture something other than rocket fuuel and O2 from the regolith. A forge (what's a solar forge?) would be needed to smelt the metals and produce plates (to be sold to Earth). Plus we'd need to be able to manufacture more rocket fuel (again to be traded with Earth). We'd need the capability to manufacture glass/plastic for a greenhouse, adding mass to the mission.
Use what is abundant and build to last
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Terraformer -
I think the objectives of going there would include:
1. Manufacture of rocket fuel, which could also be transferred into LEO or GSO.
2. Establishment of a lunar economy based on tourism, remembrance gardens, a small educational academy, and possibly medical treatment centre for persons with arthritis.
3. Testing of all Mars ISRU proposals.
4. Establishment of a permanent human presence on the Moon (lined with 2).
The Moon would offer some ISRU options that are possibly less clear on Mars. A solar forge must be easier to operate there I would think. Also, it might be possible to build a solar tower with an enclosed atmosphere - not sure about that but I guess it could be possible.
A solar forge is as I understand it a solar reflector - parabolic (?) shape which concentrates the sun's rays. My understanding is that the amount of solar radiation on the moon is far larger than on earth because of lack of atmosphere. You could generate v. high temps. with a reflector, no probs.
The downside seems to be the absence of water. Will come back to that soon.
Anyway so far we seem to be looking at:
- Multi stage conventional rocket into earth orbit, launching a possible single stage lunar lander. Lunar lander to be refuelled on the moon.
- Solar power.
- Permanent human settlement.
- Development of a lunar economy.
Not sure about melting of precious metals or metal ores. I don't think the moon is v. volcanic and it is volcanoes that are associated with gold I understand. However, I need to read up on that more.
But ferrying rocket fuel to craft in LEO could maybe be quite a productive economic activity in years to come. If it means the mass of a NASA rocket can be half what it is now, then that might be justification enough.
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The only fuel we could get totally from the Moon is Aluminum.
Do the Mars ISRU proposals include a grenhouse?
No-one's posted in the Wiki article yet.
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Terraformer -
According to the NASA site:
May 5, 2006: An early, persistent problem noted by Apollo astronauts on the Moon was dust. It got everywhere, including into their lungs. Oddly enough, that may be where future Moon explorers get their next breath of air: The moon's dusty layer of soil is nearly half oxygen.
Isn't oxygen the basis for fuel as well?
Is aluminium a good fuel? How is it used?
Back to the landing location - if it's Peaks of Light, then we need to identify a valley bottom of plateau where we can locate the base I think.
Greenhouse? I think I would still go with artificially lit hydroponic farming in an entrenched inflatable habitat. Protects from cosmic rays for one thing. For another, although there may be peaks of light, they aren't necessarily suitable for surface greenhouses. Plus, even within the peaks of light area there may be substantial variations in solar radiation between night and day.
Do you think we should aim to begin surface construction at an early juncture. The reason I ask is that I think that could be important to developing a lunar economy. If there is to be a lunar hotel, something on the surface may be far more attractive to visitors, than being cooped up in an underground facility. Eco dome construction (see link below) might be one way forward. Sandbags could be filled with earth. A good sealant cement should be possible.
http://www.calearth.org/EcoDome.htm
An eco dome "adobe" style building or connected series of buildings would look good on the moon I think. Windows would have to be limited, but perhaps one could build in an air lock to an observation platform with special glass to give people an all round view from maybe a plateau over looking hills and dramatic scenery.
Getting the hotel established and creating a revenue stream which will contribute to the upkeep of the colony could be very important.
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But for tourists to come to the moon, it would help if the fuel needed was in LEO.
The Aluminum rocket was from one of Robs posts.
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Yes, fuel taken from the moon to LEO or whatever earth orbit makes most sense.
We really need to drive down the cost of space travel and this is one way. Perhaps with a reusable lunar lander and LEO fuelling, we can make substantial inroads into cost. If we can get the cost of the launch down to $5000 a Kg and the overall cost of a three day stay to say $250,000 I think we could be in business. There are lots of multi millionaires who would consider that sort of payment for a once in a lifetime adventure. It would be such a status symbol as well.
With this revenue stream we could fund the resupply and expansion of the colony.
Remember, once in operation, the hotel would cost very little to operate. There will be no rent, no taxes, no fuel bills, no licensing, no bureaucracy to deal with, no advertising to pay for and no labour costs as such.
The itinerary would probably be something like: one day acclimatise within the hotel, one day lunar rover expedition and one day moon walking/having fun.
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Which, interestingly, mean it would cost more to get into space than to stay at a space hotel.
What would be the primary revenue stream? Fuel, Lunar materials (Aluminum, Silicon, Oxygen ect), or Tourism?
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Aluminum is the fuel used in the SRB's. So no, not very good.
LOX is technically the oxidiser, but as far as oxidisers go, it is basically the best. So for aluminum/lox mix, the Isp would be about 290 ish.
-Josh
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Difficult to say about revenue stream, but there is definitely the need for one.
I wouldn't rule out my "garden of remembrance" idea either - layout the ashes of dead people on the Moon. People might just send up a couple of Kgs - pay maybe $15,000 - or could be lower figures. Ashes are a lot easier to handle than live human beings. Hardly any running costs involved. We migth have a web cam so people could view where there loved ones were.
There would be advertising revenue from other live webcams on the moon I'm sure. Quite significant I would guess - it's the sort of thing car companies and so on would want to be associated with. I reckon you could be looking at revenue of 1 million dollars plus from that.
We could think of lots of ones - how about this for Valentine's Day -
We have a live webcam which shows your name and your loved ones plus message being embossed on metal on the surface of the moon .These declarations of love are robotically attached to magnetic poles and remain there "forever". Maintenance costs? Close to zero. Potential revenue? Quite huge I would say. We could be talking of millions of dollars. Wouldn't a message on the moon to last for all eternity be more impressive than a notice in the local newspaper? And we could probably retail that at say $200 a message. The robots could handle thousands a day. Think of the demand at Valentine's Day!
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OK recap:
1. Conventional multi stage rocket to earth orbit.
2 . Possible Single Stage Lander which will then return to earth in one piece.
3. Refuel on the moon.
4. Peak of Eternal Light location for colony/base. Are we talking north or south pole? Think south is favoured.
5. Base to be located on plateau.
6. Base to comprise: habitat, industrial zone, entrenched hydroponic facility using artificial light and commercial zone (lunar hotel and lunar gardens of romance and remembrance).
7. Commercial revenue stream to be sought from the off e.g. taking ashes to the moon or love messages.
8. Lunar economic development to be a priority:
Lunar hotel, lunar website, lunar gardens of romance and remembrance, rocket fuel production, mining for precious metals (if they exist in any quantity).
9. Solar power. Ultra thin PV should be usable within the Peaks of eternal light (ignore my previous comments on that). Can generate a huge surplus for storage where necessary. . Storage, apart from chemical battery storage will not be very necessary on the moon, but as one of the main objectives of the lunar base is to test all systems for the Mars colonisation programme we will want to try everything we can especially methane production.
So what's the latest knowledge on presence of water or hydrogen on the planet?
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As far as I know, not much Hydrogen.
Right, we need to work out how much Mass is needed to LEO, and what the crew size (Initial mission) should be. Remember, the first mission will be more mass to LEO, as there will be nowhere to refuel in LEO. Plus, the engines will either have to be able to work with bothe Al/LOX, or seperate engines will be needed.
Anyone added to the Wiki?
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for storage, I found this: http://www.newmars.com/forums/viewtopic.php?t=2576
What do you think?
-Josh
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Jumpboy -
That looks a little cutting edge for me. In outlining this mission, I think we want to stay with existing technology as much as possible. But feel free to argue your case!
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So for the overall structure of the mission, we are looking at the following themes:
1. Launch
2. Landing
3. Habitat and zones
4. ISRU
5. Lunar economic development
6. Return to earth
Under no. 4, what are the main Mars-related capabilities we want to test?
I would suggest:
Hydroponic farming with artificial lighting growing a number of crops. However, owing to one sixth gravity, these may be more limited than on Mars.
Oxygen from regolith + artificial air manufacture
Water manufacture and water mining
Raw material mining - metals and ceramic materials
Smelting
Metal shaping - rolling, extruding, beating etc
Glass making
Ceramics
Gas production (methane, hydrogen)
Use of CNC machines - lathes, grinders etc. to product containers, tools, screws, machine parts etc.
Manufacture of range of products e.g. containers of all shapes and sizes (in glass, metal and ceramics), tools, simple furniture, kitchen ware, a range of polymer products, solar panels, solar reflectors, cabling, wiring, switches and other electrical control equipment, electric motors, chemical batteries, turbines, gas holders, light bulbs or diodes, simple clothing, nutritional solutions and hydroponic farming equipment.
The emphasis of production would be on creating the ability to replicate all aspects of life support: the power system, artificial atmosphere, machinery, agriculture, and habitat - all with minimal resupply from earth.
Although I don't think we can attempt that here, what is required in effect is a Product and Parts Inventory of everything used in life support/economic activity on the moon colony broken down into constituent parts. Matched against that we need a Production and Process Plan identifying all items that need to be produced and how they are to be produced.
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What crew size are we looking at? And does anyone know how much mass is required to LEO to reach the Moon?
Are we going to use Aerocapture?
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Well if it was my choice I'd go with two crew of three - two separate landers that is, as that's how I'd like to go to Mars. So a total of six initial colonists.
But if we open the lunar hotel serving perhaps 20 guests at a time, then I think we'd need at least three hotel "staff". So maybe after a year or two you would be looking at a habitat with six colonists and a lunar hotel housing 23 guests and staff - total 29.
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