Sorry, I did not mean to disparage engineers. Of course there is always a choice to seek new employment.

As to the duration of a BEO return time, I was limiting my response to cis-lunar missions (my own current interest); for interplanetary missions years would be appropriate.

Mitt wanted to “privatize” NASA. Take your pick.

I do not think this is a left right problem at all. It is a corporate profit problem; space is hard money so for now any space program needs to wait until the easy money is all gathered up. Compare a Spaceship and Missile Submarine and there is far more money to be made underwater.

Follow the money if you want the truth; politics is all about deception and is a distraction.

Excellent comment Joe.
As a mechanic I have cursed helicopter designers roundly and frequently for some of the more difficult maintenance procedures. For example to change the windshield wiper motor on the old Sikorsky H-3 you have to disassemble most of the nose compartment. Then you have to ground check all the systems you reconnected- takes a couple people half a day to loosen 4 bolts on a 3 pound little motor. People might think a windshield wiper motor on a helicopter is not a big deal but it is on a dark and stormy night hovering over a ship at sea.

Engineers that design these systems sometimes have no choice given their time, budget, and other constraints, but to just make it work no matter how ugly it is. This might seem shocking when considering the tens of millions rescue helicopters and other aircraft cost these days but it is business as usual. In my view the Apollo 1 fire was a central event of the Moon program. There is no cheap. In fact one of my technical schools in the military was “hi-reliability soldering” which existed because of the huge quality control problems that NASA solved in the 60’s.

“But for a BEO vehicle the time required for earth return could be days to weeks.”

Years.

Actually, under Constellation Systems, the Orion Vehicle was being designed to support a Lunar Base. That top level requirement was flowed down (by the Constellation Systems Architecture Requirements Document – CARD) into all its systems requirements.

“If you needed a capsule, perhaps as an emergency crew escape pod, then either the Dragon or the CST would be cheaper and just as capable.”

You would definitely want an “escape capsule”, at least until a safe haven other than earth can be trusted. But neither the Dragon nor CST-100 (as currently designed) would meet the requirements.

Since SpaceX is secretive about the details of the Dragon, I will illustrate with the CST-100 design.

The CST-100 circulation fan system is designed to be fault tolerant (that is if the fan fails it is not a catastrophic occurrence), by over sizing the breathing gas tanks. If the circulation fan system fails, it is backed up by “blowing down” the tanks, which will give sufficient hours for the vehicle to land. But for a BEO vehicle the time required for earth return could be days to weeks. Therefore the fan system would have to be redundant. That may sound simple to you, but it is not. Not only would it require the additional fan and ducting (which would take up pressurized volume and increase the power needed to circulate the air through the increased flow path), it would increase power/cooling requirements causing changes to those systems as well.

Multiply that change by similar ones required for other systems and you soon have a very different vehicle (in fact one probably very much like the Orion).

I do not mean this in any way to be derogatory to Boeing or the CST-100 design, they are trying to develop the cheapest, lightest, simplest LEO “taxi” they can (exactly as they should be), but the BEO requirements are much more stringent.

And you mention most of the other types of propellent in some fashion GB……… It might be helpful to delineate the theaters and restrict nuclear propulsion to outside of the Earth’s Magnetosphere. This is of course not a perfect dividing line because said magnetic field shrinks and expands. I encourage you to think of the “arena’s” where humans spaceflight can be expanded as two circles; GEO and lunar polar orbit.

In my view the third arena is beneath the Moon using nuclear excavation. Hovering over a spot on the equator 22,236 miles above the Earth or in a polar orbit above the Moon or in an underground lunar factory; these are the 3 places humans will be working hard. I think your speculation on commerce between GEO an lunar polar would be interesting and a far better use of your brain cells.

Just remember you can lift thousands of tons of product off the surface of the Moon using nuclear propulsion because it is outside the Earth’s magnetosphere (propellent byproducts will not return to Earth). And you can produce thousands of tons of product in lunar underground factories. This “product” has so far been identified as solar power arrays to beam energy down to the Earth.

I am not quite sure where your fuel depots fit into this. I think the whole fuel depot concept is a fabrication of New Space advocates trying to apologize for their inferior lift hobby rockets.

As far as the human space program, Obama never made it a secret that human space was not his priority, it wasnt even an interest, and that he was going to attempt to divcert funding.

As far as commercial crew, so far it has the best potential for the US to maintain a human space flight program. Orion is a dead end and personally I wouldn’t be too surprised to see it cancelled once any other vehicle becomes available. The only potential use for an Orion is an Apollo like lunar mission, and we already saw with Apollo that it wasn’t sustainable. Sustainable missions would require a lunar outpost or base; it might be a mobile base which would be used for an extra need period as crew members do e and go. But that is a third step. The first step is an earth orbit to lunar orbit and back transit vehicle, and the second step is a reusable orbit to surface lander and ascent vehicle-probably 2, one optimized for cargo and the other for crew. No Orion is needed. If you needed a capsule, perhaps as an emergency crew escape pod, then either the Dragon or the CST would be cheaper and just as capable.

A gravity tractor with a mass of one ton can deflect an Apophis sized asteroid with two years lead time.

Take your pick.

Source, “Death From the Skies”, by Phil Plait.