Apollo was beyond low Earth orbit (LEO), not beyond Earth orbit (BEO). The moon is in Earth orbit you know…

I didn’t say manned spacecraft. My point was that cryogenic propellant is an unproven technology for spacecraft and is likely to remain so for the foreseeable future – at least for long duration applications, which exploration in translunar space would be.

If you are calling Apollo BEO then you are wrong again because it took an HLV with hydrogen upper stages to get that “space craft” to the moon.

First of all, Apollo wasn’t beyond earth orbit at all. As for the HLV, if they had transferred the lander and capsule separately, with L1/L2 rendez-vous and if they had used EOR with a separately launched EDS (as Constellation and DIRECT wanted to do) then they would have needed neither an HLV nor cryogenic propellant transfer. Or even any kind of propellant transfer because the lander was small enough to be transported fully fueled.

The reason I’m in favour of using propellant transfer is that it would create a substantial market for small launchers which I believe would lead to a breakthrough in commercial launch prices. It would also allow you to land supersized payloads on the moon or to propel a Nautilus style spacecraft to high Mars orbit. I’ve pointed this out before and you still haven’t addressed my argument. Your claim that either an HLV or cryogenic propellant transfer is necessary has been disproven.

A BEO spacecraft will require massive radiation shielding. I will just keep repeating this because everyone just keeps ignoring it.

No, you merely claim people are ignoring it when they’re not. Launching massive amounts of radiation shielding can be done without an HLV, because the ideal forms of shielding (water, polyethylene slabs) are easily divisible and can be installed by the crew from inside the spacecraft, without even needing spacewalks.

“A BEO spacecraft will require massive radiation shielding. I will just keep repeating this because everyone just keeps ignoring it.”

Are you really? Going to repeat this? Great. I was afraid you might try something new. Ever heard of this? http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001926/

“Like I said before, It is pathetic the arguments against anything not in the infomercial for private space jaunts to the ISS.”

And what you don’t realize is that any exploration plan that depends on the whims of Congress is doomed for mediocrity. Just as Congress cancelled Constellation with broad bipartisan support, they can cancel any future big ticket programs that don’t meet their budget needs.

$20B/year doesn’t buy very much, and so far Congress hasn’t even funded a payload for the SLS, and complex payloads take at least a decade to get ready for launch.

Get used to disappointment, because you’re in for a lot of it.

“Difficult, not impractical. The art will be mastered. Fortunately, we don’t have to wait for that. Fully fueled Centaurs can be launched on a Delta-IV Heavy and storable propellant is good enough for spacecraft. In fact they are excellent for spacecraft, which is why cryogenic spacecraft don’t exist. So not only are you wrong in your claim they are obsolete, you are going against your stated intention to only use conservative technologies.”

If you mean spacecraft as in BEO, there have never been any so you are imagining things. If you are calling Apollo BEO then you are wrong again because it took an HLV with hydrogen upper stages to get that “space craft” to the moon.

A BEO spacecraft will require massive radiation shielding. I will just keep repeating this because everyone just keeps ignoring it.

Like I said before, It is pathetic the arguments against anything not in the infomercial for private space jaunts to the ISS.

I’m deliberately proposing we remove it (as well as the need for an HLV) from the critical path while making sure depots still get funded and can be used as soon as they become available. That to me seems like a wise way to deal with something that is both highly desirable and technically challenging but not necessary for something that is crucial (cheap lift). In the mean time the combination of refuelable spacecraft using storable propellant and fully fueled cryogenic upper stages launched on EELV-class vehicles will give us most of the benefits of cryogenic propellant transfer: exploration beyond LEO and a large and competitive market for propellant launches.

As for storable propellant- if you look at the ISP of the storables and calculate how much will be needed to fly an adequately shielded spacecraft BEO- you get battlestar galactica.

I have actually done the sums and I found the problem was quite manageable as long as you restrict use of hypergolics to the segment L1/L2 to beyond (and even back!), leaving LEO to L1/L2 to cryogenic stages, most likely Centaur or DCSS. Initially the cryogenic stages could be launched separately and fully fueled on an EELV Heavy for EOR in the same way as Constellation (or DIRECT) intended to do. Once cryogenic depots became available, you could launch them dry and only fuel them once in LEO.

This approach would give us most of the bang (and do so very soon) for much less than the total amount of bucks. A good strategy in general, but especially in times of shrinking budgets.

Protection doesn’t require an HLV, but – like exploration – it needs a spacecraft, i.e. precisely the sort of thing that is being starved for funding by SLS. We already have launch vehicles that are more than up to the task. Sidemount is also not the best choice if you did want an HLV. Sidemount (like all SDLVs) is the choice of fanbois and people who want to protect their phoney baloney jobs.

Fair competitive redundant procurement is not part of this; there is no competition with Sidemount timewise, liftwise, or in any way.

EELV Phases 1 and 2 and maybe even 3 would be better choices.

In addition to protection it will open up the solar system to exploration and colonization

No it won’t, it will be far too expensive for that, unless you count putting a handful of people a year on the moon as opening up the solar system. And if you believe – against all evidence – that the Shuttle mafia in Huntsville and Houston won’t screw things up again as they have done so many times in the past three decades.

Let me remind you of Akin’s 39th law of spacecraft design:

39. The three keys to keeping a new manned space program affordable and on schedule:
1) No new launch vehicles.
2) No new launch vehicles.
3) Whatever you do, don’t decide to develop any new launch vehicles.

The solar system won’t be opened up before LEO is, and LEO cannot be considered to have been opened up until significant numbers of people can afford to go their on their own dime, without any ongoing government subsidies. As far as I can see that means it requires cheap lift, not heavy lift. I know you don’t believe in cheap lift, or at least you say you don’t. In that case the solar system will never be opened up.