First, understand that “Space Travel” by definition means going somewhere. Low Earth Orbit is NOT space travel. It is going in circles.

Second, understand the difference between “Space Flight” and “Human Space Flight.” Sending a micro satellite that weighs a few pounds into Low Earth Orbit and sending a human being beyond Lunar orbit into deep space is not the same thing.

Third, understand that physics have not changed in the 45 years since human beings first left the gravitational field of Earth. This includes exhaust velocities and material science; no unobtanium or wishalloy has become available.

Keeping these three things in mind, consider the whole point of a multi-billion dollar civil space program. It has not changed any more than physics has; human travel to new worlds. So to define this goal in a form less conducive to misleading the public and in the interest of clarity, consider the term HSF-BELO: Human Space Flight- Beyond Earth and Lunar Orbit.

Starting with HSF-BELO as the fundamental activity, much of the public confusion and opportunity for scamming the taxpayer with gimmicks, gadgets, and cheap and easy solutions to problems that do not exist disappear. All the smokescreens become transparent and the money games no longer befuddle.

Now consider the H in HSF. Long term cosmic radiation exposure and zero gravity debilitation and several problems that arise from the two, such as mutated pathogens, depressed immune response, and ineffective irradiated drugs, all make HSF-BELO primarily a medical problem. This is the dirty secret that means all the grandiose plans using unshielded chemically propelled spacecraft without artificial gravity for human missions in deep space are…….fantasy. This is not stopping the industry and certain “entrepreneurs” from making a profit off deceiving the public into thinking it is possible.

And that is the scam.

So if you are talking about refueling satellites or space tourism in LEO you are talking about what companies like SpaceX and ULA are talking about; but you are not talking about human beings traveling in deep space- that is different. If human travel to new worlds is what the taxpayer thinks they are paying for they are being scammed.

I will keep on repeating it as long as Dr. Spudis will let me; The Moon is the key to any human travel in deep space because NASA cannot play with nuclear energy anywhere in the Earth’s magnetosphere. Chemical propulsion is worthless for pushing massive shielding around the solar system.The Moon is the only place to assemble, test, and launch nuclear missions. The Moon is also the only place where thousands of tons of water- in the form of lunar ice- can be found for cosmic ray shielding.

A Heavy Lift Vehicle is the most efficient way to get to the Moon. It was a half century ago and it still is. The same cheaper-smaller- is-better- fuel depot concepts were considered in the late 50’s and rejected as impractical. Nothing has changed. All the flexible path private space propaganda is about avoiding the hard fact that there is no cheap. And filling shareholder pockets with tax dollars. It is a scam.

I could expand this comment- easily expand it into a 300 page book with pretty pictures explaining and illustrating all the history and problems of the flexible path and the nefarious political connections to the military industrial complex. But who would read it? As I commented earlier, not the people I see holding their pants up.

Like the race to the Moon, only fear will drive the public to pay attention and support a real space program. What I am most afraid of is an impact or an engineered pathogen and a Moon base answers both threats.

If you are talking about the 2009 study “A Commercially Based Lunar Architecture”, yes I have. While it talks several times about how expensive HLV’s are and the advantages of using existing hardware, their architecture requires new hardware as well.

Just one example, orbital depots themselves. But while they show lots of illustrations and mass estimates, they make no attempt to cost the depots. That makes a study purporting to show the greater efficiency of their proposal (at best) incomplete.

You would be better off looking at “Using the resources of the Moon to create a permanent, cislunar space faring system”. It is co-authored (along with Anthony R. Lavoie) by Dr. Spudis. I am not trying to curry favor with our host, it is the only study with which I am familiar that makes a good faith attempt at costing an orbital depot.

Have you read ULA’s proposal with ACES based depots?
I fail to see a scam in it. Where do you?

As for the rest…we’ll just have to wait and see how it turns out to see whose opinion is valid.

Generations of research scientists have come and gone in the lucrative field of fusion research. Taxpayers have footed the bill for the promise of clean energy. It was not a promise- it was a scam. The deception is simple- placing fission and fusion in the same category as if one is just an improved version of the other- and governments are happy to fund it. Why? Weapons research in disguise.
Pile a bunch of plutonium together and you have fission; try and recreate the conditions in the heart of a star inside a reactor and you are trying to do something completely different. You figure it out.

“It seems more a case of fear of the unknown-”

No, it is a case of trying to make money with smaller launchers and higher launch rate- and a great deal of complex and expensive new hardware- as a substitute for a HLV. There is no substitute- it is a scam.

“-the success of CRS 1 and 2 mean nothing?_

Less than nothing; private space is the worst thing that has ever happened to space exploration.

The hobby rocket is inferior and obsolete- the technology was originally paid for by the taxpayer and now we are getting charged for it again. There is no cheap.

That means the average payload per flight would have to be 3,667 lbs.

CRS-1 and CRS-2 carried a total of barely 2,000 lbs. combined. So they represent 1/6 of the flights and only 1/22 of the payload required to fulfill the contract.

It is also curious that they are so limited in up-mass. Their website still lists the Dragon Cargo vehicle up-mass capability as 13,226 lbs. So they only signed up to deliver 27% of their claimed up-mass capability and are, so far, delivering only 28% of even that reduced figure.

Based on that I would say CRS-1 and CRS-2 mean a great deal less than you think they do.

I never said fusion was easy.
We did underestimate how difficult it is, yes.
But it is not a reason to give up.

As far as cryogenic depots go, what’s wrong with ULA’s idea?
Seems to be the most workable idea for depots we have.
For about the price of an HLV, we get twin depots at LEO and L2.
It seems more a case of fear of the unknown than a case of technical impossibility.

-“Which is to pander to political contributors like Musk and the rest of the private space snake oil salesmen.”

So the success of CRS 1 and 2 mean nothing?

Sorry, afraid so. heavy nuclei and zero gravity debilitation are both issues that not only make deep space flight primarily a medical problem but determine the primary characteristics of spaceships (massive shield, nuclear propulsion) as secondary necessary features.

http://engineering.dartmouth.edu/~d76205x/research/Shielding/docs/Parker_06.pdf

As for fusion- there are only two places it will ever work as advertised; in a star or in a bomb. Plenty of people have retired after spending their whole careers trying to make commercial fusion work- and they will continue to retire. There is only one plan for commercial fusion that has ever had the possibility of working.

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

People have become so used to accepting the popular culture view of reality they do not even understand the basic facts about what they so confidently state as fact. If it was as easy as they have been led to believe fusion would have happened a long time ago- and this includes the whole stable of myths such as reusable launch vehicles, cryogenic depots, and single stage to orbit.

As long as the public remains uninformed about how difficult all these supposedly easy innovations are we will make no progress and continue to be duped into believing NASA actually plans on going to Mars and other such smoke screens to hide their real agenda-
Which is to pander to political contributors like Musk and the rest of the private space snake oil salesmen.

Shielding needn’t be heavy, BTW.
Just place the crew module in the middle of propellant tanks. And have polyethelene bricks make up the outer walls.

Fusion energy does not defy physics.
We keep meeting with failure because of how difficult it is, not because we’re trying to bend physics in ways it’s not meant to.
We’re learning as we go, too. We’ve learned more about plasma physics to figure out how to do better.

Remember, we also were on a learning curve with rockets too. Recall all the failures with the early rockets? And how about with the problems of Apollo?
Imagine if scientists felt the same way about those failures as you do about fusion.

The only asteroid worth sending human beings to has been reclassified as a dwarf planet; Ceres. Going there will require a Moon base from which to launch a nuclear propelled spaceship with massive cosmic ray shielding. Such a mission could be launched within 10 or 15 years with the same amount of money being spent on some cold war toy programs that do not work and never will. One example being;
http://www.bloomberg.com/news/2013-03-19/obama-backs-unproven-missile-defense-for-uncertain-threat.html
9.7 billion dollars just for missile defense this year. It is similar to commercial fusion energy- a nearly impossible feat of defying physics by trying to put a star in a box- in that hitting a bullet with a bullet is never going to work in the real world. Literally trillions of dollars have been spent on developing these technological wonders and decade after decade they keep failing simply because the laws of physics do not bend that easily.
We know how to travel in space- yet we continue to expend resources elsewhere. If star wars and fusion and other such money holes were accomplishing anything encouraging I would have no problem with it. But they will probably never work as advertised.
Not to say that some of the technology is not useful; the Gyrotron was developed from fusion research and may enable beam propulsion.
http://news.cnet.com/8301-13772_3-20020131-52.html

These things are not “tinker toys”. When you have a set of stages (designed to fly as a one stage unit) put together in parallel you do not just lash them together with rubber bands.

A good example is the RS-68. At one time Constellation Systems considered using them on the Ares V, until they discovered that the closer arrangement would cause plume impingement (which would have destroyed the vehicle) and returned to the SSME’s. In theory the RS-68 could be redesigned to be used in a different manner, but that would make it a different engine and would compromise your desired commonality.

A different configuration vehicle as you describe would require different ground handling and launch pad accommodations. Different skills would also be required for the ground crews, any configuration that only fly’s a small number of times will require special facilities and training (including refresher training) for its ground crews.