The ideas killer seems to be orbital dynamics or whatever the more correct term for it is.

“If the crew is jettisoned in a capsule, is it possible for the rest of the CEV (over a long period of time) to slow down enough to be reused perhaps years later? Would an extensive period of time in the harsh environment of space render the cev useless by the time it could be used again?”

I don’t know the answer to that but it seems we can operate an ISS over a pretty long period of time…

Actually I think that if we could get the technogy plan that the WH wants and some smart out-of-the-box thinking we might do something really spectacular. But we’d have to fight the private interests (industry, Congress, you-name-it) and accept that most will not happen during our life time. Unfortunately. Take the past 40 years of spending for nothing and I guarantee you with my hindsight crystal ball we could have been much closer than we are to a real deep space infrastructure. Commercials should have been brought it after Shuttle one way or another in a fixed cost kind of way. Look at the new HEFT study at NASAWatch. Very cool very ambitious and very likely to fail plan. Why? Where the heck is the sustainability over multiple WH/Congress being addressed? In order for NASA to replace something they cannot actually complete (Constellation) they plan something even more costly/difficult with similar systems!!! Way to go. The secret lies in “pay as you go” and “small steps forward” and in the same vein “modular/expandable” architecture.

I have advocated here and elsewhere a revival of NIAC and NASC to address strategic planning at NASA and coordination with stake holders. It looks like NIAC may come back. We’ll see if it is to address some tactical research issues or the big picture or both. If no one is actually trying to tackle the big picture then we’re bound to see over and over again plans to the Moon, Mars, NEOs without financial merit.

We shall see.

If the crew is jettisoned in a capsule, is it possible for the rest of the CEV (over a long period of time) to slow down enough to be reused perhaps years later? Would an extensive period of time in the harsh environment of space render the cev useless by the time it could be used again?

Looks like we are stuck with throwing everything away for the time being.

Good stuff. Thanks.

All in all and again, it depends how much cash you have and what kind of infrastructure you want to develop. One might imagine vehicle docking with space station from say the Moon. And a taxi vehicle to and from the station. However with the current technology you’d still have to slow down with the atmosphere. An aerobraking would also require some thinking for abort/emergency landing. This probably means a much larger than a capsule vehicle that would include emergency pods/capsules.

So Byeman’s answer is a little short on substance, sorry. Until you make the relevant trade strudy with cost/schedule/technology there is no one right answer.

Sidenote: In the early stages of CEV there was a plan to leave a vehicle at L1 but the cost and risks if I remember correctly killed the option.

Hope this helps…

“No and no, because the weight of propellant to brake into earth orbit is more than 10 times the weigh of a heat shield and the constraints on the design of the vehicle.”

So we should just make all CRV’s designed to return from L1? Could you make L1 (or maybe any of the Lagrange points) the place where you climb into a capsule for the ride back home? Your first no is a little fuzzy.

I’ve been doing a cost study for a Lagrange mission that utilizes mostly off the shelf technology (Node 3, Delta IV Heavy, etc.), but my biggest unknown was fuel requirements getting to/from L1. I was thinking of bringing the whole exploration vehicle back to LEO and do crew rotations there, but what you’re suggesting is that to reduce fuel requirements dramatically, I should do crew rotations at L1 instead.

Btw, my goal was to see how much could be done with $10B, and if I use Delta IV Heavy with ULA’s ACES tankers, then I was coming in around $7B for just the hardware & logistics part. However, if I use Falcon 9 Heavy ($95M/flight), the costs fall to $5B. Plenty of assumptions that have to get validated or refined, but I think I’m in the ballpark, and the space hardware is reusable (follow-on missions get dramatically less expensive). A fun little exercise, especially since I like to focus on cost and using existing technology (vs building custom every time).

“Is slowing down the greatest obstacle on the return leg to Earth?”

No and no, because the weight of propellant to brake into earth orbit is more than 10 times the weigh of a heat shield and the constraints on the design of the vehicle.