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Tritium

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Gravity_Ray":pf8obiaj said:
Tritium

Good questions and let me answer some of them.

We here at this forum want to go to the Moon and establish a base (and some scientist and engineers too), but we the American people do not want that. Most Americans are busy with their lives and don’t know a Moon base from a Moon sandwich. Frankly they are easily swayed by one liners like “why spend money on the Moon when you can buy sandwiches for hungry people" or some such nonsense.

There is nobody that will disagree that Apollo got us to the Moon, but at what cost? Do you know that NASA was spending something like 5% of the federal budget to get to the Moon and that was just a boots and flags program. Right now, NASA budget is around 0.5% of the budget and the Congress still cuts them whenever possible. Cant blame them, they are trying to get re-elected by the people that want to buy sandwiches for hungry people.

The problem with the Space Shuttle is not funding, although it is amazingly expensive to get 7 people into space with some hardware per flight. The problem is that the Shuttle is side mounted on a tank that sheds ice and damages the tiles of the Shuttle. The shuttle is a very complex system and has a failure rate of 2%. Imagine if you sit in your car or a plane and 2% of the time you are going to die! And these shuttles are expensive so its not you can just buy another plane or another car.

The United States still has a can do attitude. But that attitude like you said comes more from the car manufacturers or the airline industry, not from the government. So the right choice now is to move most of this lifting to LEO to private companies instead of NASA and let NASA do the harder research. As the se private companies get better at LEO and a small market develops (from getting NASA to LEO, or from getting paid customers to LEO, or even point to point travel through sub-orbital flights) they will get better and cheaper; exactly like the airline industry or the car industry.

NASA is a well managed government organization, they are very good at what they do, but they have to dance to the tune of a Immoral and Crazy Congress that changes its mind at a drop of a dime or a vote.

Lets give private industry a chance here, and see how they are doing. I have been watching NASA since the late 70s and because of budget issues they are still in LEO. If the private companies cant cut it, then what do we lose? I mean the Constellation program wasn’t going to get anybody to the Moon until around 2030 anyway.
Thank you Gravity Ray for a very concise,well written response which was direct and just about perfectly summed up the situation.

My hope is that we keep the ball rolling and through cooperation between the private companies and NASA,as well as ESA and the Russians,that humanity gets the mission accomplished,which should be achieving a Lunar and Martian colony which are both self sufficient as soon as possible in the near future.

So,I can only hope that NASA will manage what funding it does get to brainstorm the new technologies,such as VASMIR and the use of nuclear reactors to provide the energy requirements for the plasma production for propulsion and the life support systems for a Martian cruise ship to get us there and back much more quickly than chemical rockets.As well as figuring out the game plan for the exact developmental stages of both the Lunar and Martian colonies,the L5 station,the orbital fuel stations and manufacturing facilities which would allow the Mars ships to be assembled in space,receiving materials and supplies from both the Earth and Lunar sources.

I am getting old,and I'm kind of saddened that I now realize I probably won't get to go to the Moon,or to Mars in my lifetime.There is a glimmer of hope that I might get to ride to LEO,or a sub-orbital hop,and it's on my "bucket -list".To see the Earth from an altitude where I could see the whole planet from space,with my own two eyes has always been a dream of mine.And back in the late 60's I really thought that I might be whacking a golf ball into an amazing trajectory on the surface of the Moon.But the whole NASA/space thing died down due to economic restraints(the we might be able to buy a sandwich for somebody thinking) and we have cell phones and personal computers,but no flying cars,and no space cruise ship vacations....(sigh).I keep hoping some kid at MIT or the University of Texas ,or someplace will grab a piece of chalk and write the mathematical formula for anti-gravity so I can back out of my garage and rise to a few hundred feet and zip down to the coast for an afternoon,and then boogie on back home before dark.But I digress.The point is,it seems as though our technological brealthroughs have slowed down to a crawl,when I expected them to increase exponentially,building one upon another.Now I'm really getting off the track and thinking that this could be a great subject for a new topic... :lol:
 
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rockett

Guest
Gravity_Ray: I would like to thank you for your summary also.
Tritium: I can sympathize with your bucket-list, I share it, having grown up with the space race.

This is also "food" for another topic :D . (Your sandwich thought brought it to mind Gravity_Ray) It was either Larry Niven or Jerry Pournelle that postulated ("The Mote in God's Eye", I think) that there was a point where global population densities reached a "tipping point" and consumed so much of the planetary resources that there was nothing left to sustain becoming a space-faring race. I suspect that we are dangerously close to that point now, if not past it...
 
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pathfinder_01

Guest
DarkenedOne":3w4crunj said:
As for closed loop life support, this sort of thing can be tested on the moon, where it's needed. On other celestial bodies (like Mars, the asteroids, or Jupiter's moons), we can mine water and other useful substances (fertilizer from the nitrogen in comets) from the ground beneath us. Closed loop life support is not necessary if you have ISRU, which we can test with our first manned Mars mission.
[/quote]

Actually Closed loop would be needed for mars as well. Closed loop will probably be more energy efficient than ISRU and provide extra back up should your ISRU fail. With closed loop you could put the power that would be going into making water and oxygen for drinking and breathing into say propellant production or food production. You can then use the ISRU to just top off what ever losses occur or grow the colony as needed.
 
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edkyle99

Guest
DarkenedOne":2hxcqvhb said:
edkyle99":2hxcqvhb said:
Nobody's suggesting any alternative that won't end up costing roughly the same. A lunar mission that requires a certain landed mass requires a certain launched mass. Until someone invents a Star Trek transporter, launched mass converts to lots of dollars. If the people don't want to pay, fine. But don't try to fool people into believing there is a less expensive way to go to the Moon.

- Ed Kyle
Yes people are suggesting alternatives will be cheaper. That is why NASA is looking into these so called "transformative or game changing technologies." They are game changing because they offer significant benefits over traditional technologies and methods.

There are a great deal of technologies that if developed and if they work will dramatically decrease costs. I will go through some of them for you.

ISRU promises to reduce launch costs by gathering needed resources from the local environment thus reducing the necessary amount mass that needs to be shipped.

VASIMR promises to decrease costs by increasing payload capacity and decrease fuel requirements thus reducing cost.

Closed air-loop life support promises to reduce human consumption thus reduce the size of spacecraft, and resupply mass thus reducing cost.

Inflatable habitats promise to provide habits that are larger and cheaper than the aluminium ones that NASA built the space station with.

Fuel Depots promise to allow NASA to stockpile fuel provided by low cost already developed commercial launchers without the need for high cost super heavy launch vehicles.

I could go on, but yes the idea is to pursue these technologies that have largely been neglected in favor of traditional methods such as Constellation and Apollo to get us to these locations more affordably.
R&D is always worthwhile, but there is no guarantee that any "transformative" idea will pan out, in a affordable manner, during this decade or the next, etc. If we want to go to the Moon now, we have to use the available technologies.

As for "low-cost" commercial launchers, where are they? The EELVs cost big bucks to fly. Even Mr. Musk has been steadily raising prices on his Falcon 9 (it is up to $51.5 million now, double what SpaceX originally advertised, and rising fast).

- Ed Kyle
 
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halman

Guest
There seem to be some grave misconceptions floating around concerning NASA's reason to exist. Most people believe that the government agency was created to find ways to take people to Mars, judging by the posts that I have read. The concept of government investment to stimulate private sector development seems to go right over these people's heads. For some reason, they insist on believing that the taxpayers of the United States will pay for a handful of people to travel to Mars so that a colony there can be created, which will be supported by further spending of taxpayer's money.

As far as I can tell, the entire Constellation program was created by the Bush administration to prop up ATK, a military contractor which builds solid fueled missiles. There was no intention of actually sending people anywhere, because there was no money provided for the hardware necessary to land, explore, and return. The crew capsule would be the absolute minimum required to support a short stay in space, to allow personnel to transfer to some undefined vehicle for the journey to somewhere beyond Low Earth Orbit.

To accomplish these very minimal goals, all other spending on human space exploration would have to be curtailed, and our existing manned space travel capability would have to be scrapped. At the very most, the Orion capsule would carry 5 people, who would each have less room to move around in than in a phone booth. All of this spending was justified with the goal of 'traveling to the Moon, and then to Mars,' which happen to be the most popular destinations in the Solar System. If Mercury were the most popular destination, the Bush program would have cited that as the goal of the Constellation program.

Everything I have seen tells me that there was never any intention of sending people anywhere, of building deep space vehicles, of studying closed loop life support systems, or of figuring out how to protect people from radiation during extended missions. The whole thing was a scam, meant to lull space exploration advocates into allowing the space shuttle to be canceled, and huge sums of money to be given to ATK.

President Obama's advisers saw through the scam, and recommended scrapping the program. But they, and the Augustine commission, could not come up with a program that the United States could afford to move space exploration forward. The space shuttle was already being wound down, so there would be no man-rated launch vehicles to get people into orbit, and the commercial launch sector is still years away from being able to do so. Having NASA develop another step rocket for manned launches was counter to the purpose of the agency, because step rockets are old technology. NASA is supposed to pioneer new technologies, not compete with the private sector in existing ones.

But without the ability to put people in orbit, what could NASA do? People cite the 'wildly popular' robotic exploration programs, but that term is relative. Ask the next person you meet on the street what they think of the Cassini mission, or the Mars rovers, if you don't believe me. Or get them to tell you what the Hubble is. Folks love the pictures, but they have no idea where they came from. Here is another educational exercise: Sometime when Mars is visible, have your neighbor point it out to you.

So, what should NASA do next? I get the impression that a lot of people think that the step-rocket is the only way of reaching space, and that there is much we can do in perfecting them. Apart from making them bigger, there really is not much we can do to improve them, because we have been building step rockets for over 50 years. Engine technology is pushing the limits of material science, structural advancements utilizing composite materials offer only small weight reductions, and there just isn't much else involved.

Surprisingly, many space enthusiasts still don't understand what is involved in reaching orbit. They see a rocket taking off straight up, and they assume that it will continue on that trajectory until it reaches space. The SpaceShip One flights excited them, because it seemed that you didn't need a giant rocket to be able to go to space. Explaining that achieving orbit is not a function of going up, but of going faster, created a lot of blank looks.

Our technology for reaching orbit is primitive, inefficient, and wasteful. Most of the propellant used in a vertical launch is spent combating the effect of gravity, not in accelerating the vehicle around the planet. Perfect conditions are required for launch, and large numbers of people must monitor every facet of the launch vehicle, the range, the weather, and a multitude of other factors. These constraints are a large portion of the costs of getting into LEO, not the costs of the propellant, or the construction of the vehicle. And each launch will result in only a few people, 3 in the most common launch vehicle, reaching orbit.

There has got to be a better way, and I believe that such a way is within our grasp. While most people are talking about NASA using its funding for developing improved methods of traveling from planet to planet, I advocate that the agency commit to building the next generation of spacecraft, the one that will be in use for generations, and which will support every activity we perform in space. If we are going to be able to utilize space at all, we are going to have to be able to put more than 3, 4, or 5 people up there at a time. And we are going to have to be able to put them up there for far less than 20 million dollars each.

To find out what I believe should be the next project NASA undertakes, please read "A cheap and easy way into space" in this forum.
 
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edkyle99

Guest
halman":1wz0g5fu said:
As far as I can tell, the entire Constellation program was created by the Bush administration to prop up ATK, a military contractor which builds solid fueled missiles. .... The whole thing was a scam, meant to lull space exploration advocates into allowing the space shuttle to be canceled, and huge sums of money to be given to ATK.
ATK only derived 9% of its total sales from the RSRM contract in FY2009. The company won't live or die based on whether or not it delivers big segmented solid motors to NASA. It makes far more money making ammunition, and smaller solid motors primarily for military missiles.

- Ed Kyle
 
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neutrino78x

Guest
So from what I understand, reading the Augustine Comission PDF, under Flexible Path, the Commercial Crew option was only for LEO. It has nothing to do with going to the Moon. The only way it could is if we decide not to build heavy lift boosters that go directly to deep space objects, instead building ships in orbit, launching the modules into LEO.

In either case, the vehicle that goes from LEO to an asteroid, or the Moon, would be owned and operated by the government.

Does anyone disagree with that interpretation of Flexible Path?

--Brian
 
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Cosmicvoid

Guest
Tritium":351m5lfi said:
... and other assemblies could be boosted into L5,as a way station between Earth and Moon.
Not to seem nit-picky, but I think L1 would be a more convenient location.
 
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EarthlingX

Guest
I will just extend it at some points :
neutrino78x":17ydmdhl said:
So from what I understand, reading the Augustine Comission PDF, under Flexible Path, the Commercial Crew option was only for LEO. It has nothing to do with going to the Moon. The only way it could is if we decide not to build heavy lift boosters that go directly to deep space objects, instead building ships in orbit, launching the modules into LEO.
Like Russian plan for the Mars mission.

neutrino78x":17ydmdhl said:
In either case, the vehicle that goes from LEO to an asteroid, or the Moon, would be owned and operated by the government.
Owned, operated and developed by NASA.

neutrino78x":17ydmdhl said:
Does anyone disagree with that interpretation of Flexible Path?

--Brian
 
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halman

Guest
Space begins about 120 miles over our heads. Stable orbits are a bit higher, because of traces of atmosphere slowing down an object in orbit. Even at the altitude of the International Space Station, resistance gradually slows things down. In terms of putting something into space, the lower the orbit, the lower the energy required. Once something is in orbit, it is possible to use another vehicle to transfer that object to a higher orbit, with a much smaller total energy cost than would be required if the launch vehicle were to inject the object into the higher orbit.

To launch something from Earth to a Lagrange point requires about the same amount of energy as to launch the same object to the Moon. To use Lagrange points to assemble deep space probes offers the benefit of stable orbits, but at an energy cost similar to sending the components to the Moon.

To maximize efficiency, launch vehicles should put their payloads in the lowest possible orbit. Once there, it is possible to use a vehicle already in orbit to move the payload to a higher orbit. Such a vehicle could be called an Orbital Transfer Vehicle, or a Space Tug. (I have referred to them as OTV's in my posts. I reserve 'Space Tug' for vehicles used to change the orbits of objects not in orbit around the Earth.) An orbit 600 miles high is quite stable, as long as it is circular. The only drawback to that altitude is that it is within the Van Allen belts, and is therefore exposed to higher levels of radiation then at lower altitudes.

However, the problem of radiation shielding is fundamental to deep space exploration, and will have to be solved somehow before any long duration missions outside the Van Allen belts are attempted. Lagrange points may be excellent locations for space colonies, but they may not be the best place to assemble vehicles to be used for deep space missions. Their primary advantage is that they are near the top of the Earth's gravity well, and therefore, vehicles departing from them for deep space missions require little delta V. But that is because the delta V has already been applied.

Like it or not, Low Earth Orbit is going to be the place where much of what we do in space begins, at least for some time to come. People have gotten in the habit of deriding LEO, as a result of our doing all of our manned activities there. But LEO is the only place in space that is shielded from the energy storms generated by the Sun, and achieving LEO still taxes our abilities.
 
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pathfinder_01

Guest
edkyle99":6i5wfiil said:
R&D is always worthwhile, but there is no guarantee that any "transformative" idea will pan out, in a affordable manner, during this decade or the next, etc. If we want to go to the Moon now, we have to use the available technologies.

As for "low-cost" commercial launchers, where are they? The EELVs cost big bucks to fly. Even Mr. Musk has been steadily raising prices on his Falcon 9 (it is up to $51.5 million now, double what SpaceX originally advertised, and rising fast).

- Ed Kyle
I think that at least some of them will pan out. If only a few do we are just that much more ahead. Affordable to me means a mission to the moon should last a month be able to return a more than a few pounds of rock, be able to support more time on the lunar surface, be able to return more rocks or other samples and not cost that much more than a shuttle launch. Nasa has been able to have a budget able to support these kinds of missions in LEO for 20 years. I want to see this kind of mission at the moon without an increase in budget. I want to see at least 4-6 of this mission a year not 2 missions at year dependant on an increased budget and tossing the shuttle and ISS.

As it stands now:

Inflatable modules and ion propulsion are technologies that are ready for prime time transit to the moon and need to be incorporated into a moon mission.

Limited closed loop life support systems are currently in use on the ISS. Yes it does go on the fritz, but they probably manage to make it work long enough to save on ground support.

Not to distant (possibly ready in under 10 years):

Vasmir

Fuel depot—depending on what kind of fuel is used.

Lox can already be stored long term in orbit. Only hydrogen presents a real problem. The big issues with Fuel depots is what types of fuels does it make sense to store on orbit and where should you put them and how to handle the zero g plumbing.

How they interplay….

With inflatable you could add more radiation shielding and/or use a smaller chemical rocket for the mission. Smaller rockets are usually cheaper than larger ones. If you need HLV then instead of developing a 188 ton to orbit behemoth you could develop something smaller say 50-80 ton to orbit. The smaller rocket would probably have less technical risk and perhaps have lower development costs than the larger one.

With Ion/Vasmir you could move cargo to the moon cheaper or at least more cargo to the moon than a chemical rocket could using an equal mass of propellant. In addition these kinds of rockers are reusable as they are built to last months anyway.

This could enable longer missions with very little additional cost. What if you could park an extended duration module in lunar orbit? The module would have long term life support via a closed loop, addition crew space, perhaps heavy radiation shielding (installed in layers). It would act as a point of departure for lunar landings. In the far future it could act as a place where reusable or partially reusable lunar Lander is refueled/ refurbished but for now you could park more than one Lander at this point of departure.

Now the same crew could make multiple landings on the moon (a new capability that Apollo lacked). And lunar samples could be collected for transport via an earth bound tug (no need to figure out how to squeeze rocks into the capsule with people). Re supply of non-critical components could be made via ion/vasmir.
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Fuel depots should have been what constellation developed. It needed it. The cryogenically fueled earth departure stage with a mere 4 day linger period in orbit was silly. If your earth departure stage is only good for 4 days then launch it with the crew ala Apollo, otherwise you just set your self up for an expensive loss of mission if you are unable to get to the stage in 4 days (i.e. weather, technical delays). How many times have they had to roll the shuttle back to the hanger in the history of the program? Are hypergolic fuels that weak that even when launched separately on a 188 ton to orbit rocket they are unable to push a capsule to the moon? This part of constellation made no sense to me.

The old method didn’t give us much more than Apollo. People forget that it took more than Columbus’s bravery to reach the new world. It took funds and it took technology that made repeated voyages affordable and sustainable.
 
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EarthlingX

Guest
halman":31zt1tkc said:
To launch something from Earth to a Lagrange point requires about the same amount of energy as to launch the same object to the Moon. To use Lagrange points to assemble deep space probes offers the benefit of stable orbits, but at an energy cost similar to sending the components to the Moon.
From LEO it is a bit different picture, Moons orbit is a little further than Ls, Moon surface little less than Phobos, but it would probably need more thrust.

Wiki : Delta v budget
 
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HopDavid

Guest
halman":hpv5y90v said:
To launch something from Earth to a Lagrange point requires about the same amount of energy as to launch the same object to the Moon. To use Lagrange points to assemble deep space probes offers the benefit of stable orbits, but at an energy cost similar to sending the components to the Moon.
It's true the burn from LEO is about the same for both, around 3.1 km/sec.

However landing on the moon takes 2.6 km/sec (possibly more due to gravity penalty)

Matching velocity with L1 at apogee takes .7 km/sec

So no, the energy costs aren't similar.
 
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edkyle99

Guest
pathfinder_01":slz9t82f said:
Nasa has been able to have a budget able to support these kinds of missions in LEO for 20 years. I want to see this kind of mission at the moon without an increase in budget. I want to see at least 4-6 of this mission a year not 2 missions at year dependant on an increased budget and tossing the shuttle and ISS.
Why does NASA have to perform 4-6 missions, or even 2 missions, per year? Why not one per year, or one every other year? What is the rush? The Moon is going to be there.

Slowing the mission rate seems to me a plausible way to cut costs without having to wait for high tech that may not pan out. A LEO depot setup is one possible way to support a slower mission rate. The per-mission cost would not be any less than an Ares style mission, but there would only be one-half of a mission to pay for each year.

- Ed Kyle
 
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pathfinder_01

Guest
edkyle99":37gay2i8 said:
pathfinder_01":37gay2i8 said:
Nasa has been able to have a budget able to support these kinds of missions in LEO for 20 years. I want to see this kind of mission at the moon without an increase in budget. I want to see at least 4-6 of this mission a year not 2 missions at year dependant on an increased budget and tossing the shuttle and ISS.
Why does NASA have to perform 4-6 missions, or even 2 missions, per year? Why not one per year, or one every other year? What is the rush? The Moon is going to be there.

Slowing the mission rate seems to me a plausible way to cut costs without having to wait for high tech that may not pan out. A LEO depot setup is one possible way to support a slower mission rate. The per-mission cost would not be any less than an Ares style mission, but there would only be one-half of a mission to pay for each year.

- Ed Kyle

From publicity\public relations stand point stand point each and every mission is a chance to show the public what you are doing with their money. It is a chance to earn good will and keep what you are doing in the public mind. The fewer the missions the more likely the public is to forget just who or what NASA is.

From a political stand point. Having capability (I.E. something ready to go) makes it harder to cancel things. If the shuttle were to fly until replacement or if Ares I were sitting on the pad ready to go, I think the Obamba administration would have taken a different course. NASA’s access to LEO would not be in as much danger. Even with Apollo, money was allocated for flights despite the fact that NASA was unable to purchase more Saturn V’s. If you have already paid for it, there is more pressure to use it. This is why the shuttle survived. Granted there are limits to this as the three unused Saturn V boosters prove, but to some extent this is true.

From a budgetary stand point. If NASA does get a cutback it is not the end of the world when you have 4-6 missions a year going. Ok, we only do two or three this year as opposed to say none. When you are starting at a point where you are only able to do it once or twice a year, you have little room to give.

Another issue is cost namely fixed costs. It cost tons of money to have a capability. Things that employee people like NASA or even the private industry take people and people cost money. They have high fixed costs. It costs Ford, NASA, Space X a ton of money just to be able to do what they do even if say the factory produced no cars or NASA sent up no payloads. You get very little savings by cutting back on missions. In fact the curse of the shuttle (and frankly any rocket) is those high fixed costs. Adding a mission like the tragic STS 107 costs relatively little. If you are only going to be going once a year, then it makes it harder to utilize people in an efficient manner. I mean odds are your payload tech isn’t also trained in propulsion engineering and also can work in mission control ect. And odds are your payload tech isn’t looking for a part time job with NASA.


Although I support extending the shuttle for two years, even I must admit that flying the shuttle twice a year is not the best use of the resource.

Using some of the things developed in the shuttle, ISS, and other missions we should have been able to do more than just a week on the moon given the same money as constellation needed. The thing is some of these things such as the limited closed life support, inflatable modules, and ion propulsion should have been integrated into constellation. Constellation was literally Apollo on steroids, bigger in bulk but not through hard work and effort but through a lack of imagination. Like an athlete on steroids, it sought to win, not by playing harder or smarter but by shear bulk. They are not things that are unproven or need a little more work like vasmir but have worked and are working now. They are tools that can be used that were unavailable in the 60ies.

For instance, using the ion engine in smart-1 you could preposition about 633 pounds of supply at the moon for the cost of a shared ride into space. The smart -1 probe weighted about that much without propellant (about 176 pounds more with) and shared a ride into space with another satellite. The ability to send a package to the moon for the cost of a regular non lunar launch is something that should have been exploited. Heck even if you deployed it in earth orbit with your earth departure stage or mission for later use with another mission, the 3.5:1 ratio of spacecraft mass to propellant could make it very attractive. The only real problem is the use of Xenon as propellant (costly) but there are lots of other items that could be used like Aragon.

Using a fuel depot could radically change the earth departure stage, it now could be launched empty(meaning you don’t need quite so powerful a rocket to put it into orbit). This mass savings could go to other things, like more robust landers than Apollo, more suppiles, ect. Given the nature of the fixed costs you could get more missions with less overall cost than building an huge HLV. For instance, it might cost more total to put the ISS up via the shuttle and other rockets than it would via heavy lift, but the larger costs are now spread over more time and didn’t require the development of a new rocket.
 
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Tritium

Guest
I have several questions.

What is the best known material,or method to provide radiation shielding?

Please tell me why we cannot reconfigure the current shuttle so that it rides on top of the rocket,avoiding the ice damage issues,and revise and modify a working system to continue to be our best way to get to LEO with supplies and then land and take off again?

Once we've reached LEO,why can't we develop OTV's(Orbital Transfer Vehicles-space tugs-courtesy of one of our Space .com members)which could remain on station to tow deliveries to a higher orbit for assembly of a large,spacious craft,capable of carrying perhaps a hundred people,plus tools and equipment and supplies to establish a permanent Mars colony?

Exactly what are the freaking fuel requirements for VASMIR?

:twisted:
 
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pathfinder_01

Guest
“I have several questions.

What is the best known material,or method to provide radiation shielding?”

Not an expert but a major space fanantic.

This is not a simple question. For in space transit BEO probably hydrogen or something containing lots of hydrogen like certain plastics. For some reason I don’t understand lead actually is the worst material for protection and lighter element are preferred. Lead when hit with certain types of radiation turns into more but still dangerous other kinds of radiation. The real trouble is the amount of material needed is too great atm which is why research into radiation shielding is needed. I have had real trouble finding out just how much material is needed for a mission even if the amount were impossible to lift to orbit.

The big thing with radiation is the type, amount, and how long you are exposed to it. So, a short trip to the moon could be less dangerous than a long stay at the ISS. The ISS gets less of some kinds of radiation, but the crew is there longer. The longer the mission the bigger the problem is keeping the dose safe and on a trip to mars with current systems you could be flirting with lifetime limits of exposure. Further compounding the problem is the fact that the shielding you use in space might not be what you need on the ground for both the moon and mars.

“Please tell me why we cannot reconfigure the current shuttle so that it rides on top of the rocket,avoiding the ice damage issues,and revise and modify a working system to continue to be our best way to get to LEO with supplies and then land and take off again?”

Confused about this part. The short answer, it was not built for that.


Slightly longer answer from what I have heard a winged craft can not ride on the top of the booster. The wings act like the head of an arrow in flight and make the booster want to tip over horizontal. You need to a payload shroud or it will cost a lot of fuel just keeping the rocket on course. And that does not get into all the other problems with the idea. The rest of your question I am not sure of.

“Once we've reached LEO,why can't we develop OTV's(Orbital Transfer Vehicles-space tugs-courtesy of one of our Space .com members)which could remain on station to tow deliveries to a higher orbit for assembly of a large,spacious craft,capable of carrying perhaps a hundred people,plus tools and equipment and supplies to establish a permanent Mars colony?”

Possible, although the mars transfer craft could be a nightmare. The engineering problems are how do you refuel this thing on orbit and reuse the engines. Very possible, but not quite something you could do in under 5 years.

“Exactly what are the freaking fuel requirements for VASMIR?”

At the moment vasmir uses Aragon gas that being said it can use other materials just that the one being devolved now is built with that assumption. Sort of like an internal combustion engine can gasoline and is built for it but other ones can use other fuels.

The real issues with vasmir aren’t the propellant. It is the power requirements. Vasmir is a form of electric propulsion or more specifically it is a kind of plasma rocket. Vasmir uses electricity to turn Aragon into plasma and accelerate it out of the craft. There is a lot more to it but that is the basics. The more power you have the more propellant you can process and the more thrust you can get. This is why the amount of fuel varies so.

Electric propulsion is basically way more fuel efficient(isp) than chemical. You can carry a more mass with an equal mass of propellant. However it very low thrust (i.e. slow acceleration). Depending on the time needed for transit it may or may not be faster. It is sort of like the turtle and the hair. A chemical rocket accelerates fast but uses all it’s fuel up quickly (say ten minutes). An electric rocket acierates slowly but constantly gaining more and more speed(hours, days, months, years). There is other major difference such as an electric rocket can not use the same sort of trajectories that a chemical one can use.

On a short trip say to the moon chemical is faster, but electric would use much less propellant.

On a long trip say to mars. Electric can equal chemical or get there faster. Yes you do need 600 tons of Aragon to get there in 39 days, but an chemical rocket would need more than ten times as much propellant to do the same.

Also a electric rocket can achive a higher final velocity than a chemical one because it's exhust velocity is greater. (Assuming unlimited propelent for both and enough time).

This is why comparing chemical and electric gets complex. Vasmir, unlike some other forms of electric propulsion has enough thrust to be useful for some manned applications (a mars trip).
 
T

Tritium

Guest
Rebuild Shuttle-craft.Reconfigure launch so that shuttle sits on top of launch vehicle,avoiding ice damage.Make shuttle larger,to accommodate more crew,and cargo.
Bring crew and cargo to LEO,transfer to Orbital Transfer Vehicle.
Build Lagrange Point Assembly and Fueling Station.(LPAFS).
Build very large Mars Mission Vehicle,capable of establishing Martian Colony.
Establish Moon,and Mars Colonies simultaneously.
Drill,mine,for water,helium,etc. to establish self sufficiency for all colonies.
Use VASMIR engines for Mars Missions.
Adapt all new and applicable new technologies to enhance missions. :cool:
 
R

rockett

Guest
Heres a little more info on some of your earlier questions, liked your latest post!

Tritium":38shr5bd said:
What is the best known material,or method to provide radiation shielding?
Depleted Uranium is the best, but probably not a good idea. :?
http://en.wikipedia.org/wiki/Radiation_protection
Magnetic shield is ideal, but we have a lot of development to do. :roll:
http://www.thespacereview.com/article/308/1
Other candidates are Liquid Hydrogen, water, plastics, things like kevlar and so on, and combinations of materials.
There is a LOT of research going on.

Tritium":38shr5bd said:
Please tell me why we cannot reconfigure the current shuttle so that it rides on top of the rocket,avoiding the ice damage issues,and revise and modify a working system to continue to be our best way to get to LEO with supplies and then land and take off again?
Quite simply, the tank. We have shaved it very thin on weight, so it would have to be reinforced.
Then you will notice, the main engines are on the Orbiter, so that's another issue. Move them to the tank and you will have to re-engineer both. Adding engines to the tank alone would require a lot of reinforcement and plumbing, then you would lose upmass too.
Tritium":38shr5bd said:
Once we've reached LEO,why can't we develop OTV's(Orbital Transfer Vehicles-space tugs-courtesy of one of our Space .com members)which could remain on station to tow deliveries to a higher orbit for assembly of a large,spacious craft,capable of carrying perhaps a hundred people,plus tools and equipment and supplies to establish a permanent Mars colony?
Agreed, that is the best option and NASA has known it since the 1970s.
For example:
http://beyondapollo.blogspot.com/2010/02/five-options-for-nasas-future-1970.html
Latest incarnation:
http://nextbigfuture.com/2010/01/vasimr-plasma-rocket-for-lunar-tug.html
Then there is Buzz Aldrin's XM (I personally like his "unified space system" approach):
http://www.aolnews.com/opinion/article/opinion-buzz-aldrin-says-mars-is-within-our-reach-heres-how/19380071
Tritium":38shr5bd said:
Exactly what are the freaking fuel requirements for VASMIR?
See this thread LOTS of information and discussion on that:
VASIMR Updates
http://www.space.com/common/forums/viewtopic.php?f=15&t=19731
 
E

EarthlingX

Guest
An old article from SDC about space refueling :
Prototype Satellites Demonstrate In-Orbit Refueling

I think there were already in-orbit experiments after that, perhaps even last year, if you count out routine Progress fuel transfers, of course.

Starting points for the radiation protection info :
Wiki : Radiation protection
Wiki : Gamma ray
Wiki : Solar wind

and
Wiki : Closed ecological system

a lot to read in
Wiki : Space architecture

and answers about VASIMR, with all the links you need :
Wiki : Variable Specific Impulse Magnetoplasma Rocket

Rocket : crosspost :) :cool: ( after 16th attempt )
 
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rockett

Guest
EarthlingX:

Good info on the in-orbit refueling. Also a "demo" of it on the VASIMR vid out there.

EarthlingX":2vfb9a8n said:
Rocket : crosspost :) :cool: ( after 16th attempt )
Sorry bout that, was not intentional on my part :oops:
 
E

EarthlingX

Guest
rockett":2r9zzy8y said:
EarthlingX:

Good info on the in-orbit refueling. Also a "demo" of it on the VASIMR vid out there.

EarthlingX":2r9zzy8y said:
Rocket : crosspost :) :cool: ( after 16th attempt )
Sorry bout that, was not intentional on my part :oops:
Not your fault at all, just coincidence. Nice post, in any case :)
 
E

EarthlingX

Guest
More about Orbital Express from
Wiki : Orbital Express
Orbital Express was a space mission managed by the United States Defense Advanced Research Projects Agency (DARPA) and a team led by engineers at NASA's Marshall Space Flight Center (MSFC).
Boeing : Orbital Express
The ability to refuel, reconfigure and repair satellites has been considered a top priority for many years by both the military and civilian space launch and satellite industry.
and archived page at DARPA : Orbital Express Space Operations Architecture
The goal of the Orbital Express Space Operations Architecture program is to validate the technical feasibility of robotic, autonomous onorbit refueling and reconfiguration of satellites to support a broad range of future U.S. national security and commercial space programs.
First hit from Marshall Space Flight Center, search for 'space orbit refueling' :
Serving the Marshall Space Flight Center - Marshall Star Online (pdf)
 
E

edkyle99

Guest
pathfinder_01":cnig623u said:
edkyle99":cnig623u said:
pathfinder_01":cnig623u said:
The fewer the missions the more likely the public is to forget just who or what NASA is.
I think that the opposite would be true - that the public would pay more attention to fewer, higher-profile missions. How many people take note of the numerous Shuttle missions now? How many really realize that humans have been orbiting the Earth continuously for years on ISS? Think about those questions, and then consider how much attention a biennial (once every other year) lunar mission would get. Each mission would consist of a months-long campaign consisting of a series of launches, topped off by the final high-profile astronaut launch.
Even with Apollo, money was allocated for flights despite the fact that NASA was unable to purchase more Saturn V’s.
There were more Saturns than Apollo missions. NASA was hoping for a long post Apollo "Applications" missions program, but only got money for Skylab.
Another issue is cost namely fixed costs. It cost tons of money to have a capability.
This is the big challenge. How could NASA reduce fixed costs on a slower-mission-rate plan? Clearly, it would need to depend on existing rockets as much as possible. EELVs, etc., allowing it to leverage the existing infrastructure and personnel. The Agency would also have to design the program to be leaner from the outset, which means, more than anything else, fewer people on the program at JSC/MSFC/KSC, etc..

- Ed Kyle
 
E

EarthlingX

Guest
From Spaceref.com :
Kosmas and Posey Introduce Bill to Minimize Human Spaceflight Gap
PRESS RELEASE
Date Released: Wednesday, March 10, 2010
Source: Rep. Kosmas

Bipartisan Legislation Would Help Maintain U.S. Leadership in Space

(Washington, DC) - Today, Congresswoman Suzanne Kosmas (FL-24) and Congressman Bill Posey (FL-15) introduced legislation to maintain a robust human spaceflight program, minimize the spaceflight gap, and protect Space Coast jobs.
 
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