From Burt Rutan. I haven't had time to read the whole thing, yet (I'm still on vacation, and relaxing from a couple dives this morning), but when I do I may have some additional thoughts.

I like the quote in the picture caption:

"We hope we're building the DC 3 or Tri-Motor," Rutan says, "not the barnstorming airplane."

(refering to Space Ship Two and White Knight Two).

I haven't yet read the story, but I doubt Spaceshiptwo will ever have low cost operations because of the hybrid's solid part... Maybe it can later be adapted for true liquid engines.

mz:

Yeah, 'cause they were too stupid to think of that.

You're both right. It may be a lousy way to go from an operability and marginal cost standpoint. I think that they're trading off operability for a perception of safety. I think it's a mistaken perception, but it's not due to stupidity. That's what's great about having competition. They'll be proven right, or wrong, and we'll continue to come up with better ways to do things.

MZ:

I disagree. While the solid part of the hybrid engine will not achive the low cost and simplicity of simply "filling up" a liquid-fueled vehicle, through frequent use it will achieve a much lower cost than is now the norm.

The PM article on Rutan is only one page. The high points are that he is building SS2 and White Knight 2; that 100000 people will fly suborbital in the first 12 years of operation; and that within Rutan's lifetime there will be affordable trips to the moon (at least, lunar orbit if not landing). Also he predicts that within 500 years (!) most people who leave Earth won't be coming back; they'll stay and raise families.

I think his 500 year timeline is far too pessimistic. :)

Ed: the difficult part about that would be defining what 'human' will mean in 500 years. I doubt many, if any, existing humans will be around at that time (not that that idle prediction is testable.)

Er, should have written 'existing type of humans', not meaning individuals alive today also alive in 500 years.

Oh, there'll always be groups like the Amish and others who utterly refuse human enhancement to any significant degree.

Anyway, I would agree that 500 years is too pessimistic.

I don't know about you Paul, but I plan on being not-Amish and taking every advantage I can get, so that I will still be around in 500 years. ;) Of course, that would likely mean that I would no longer be one of the existing type of humans...

> It may be a lousy way to go from an operability and marginal cost standpoint. I think that they're trading off
> operability for a perception of safety. I think it's a mistaken perception, but it's not due to stupidity.

At the RASTE conference, Doug Shane said changing out hybrid motors after each flight was an acceptable way of getting the business started but they would want to switch to a "different kind of engine" later on. So, Scaled is already thinking along the lines of a "SpaceShip 2A."

I wonder if SS2 will still leak atmosphere. They used a pressurized tank to compensate in SS1. To my non-engineer mind, that always seemed like a kludge. It reminds me of an episode of "Monster Garage" (another "staged life" show) where they tried to make a swamp buggy that would float. They wound up with something that sank slowly enough that they could fake success with good camera work. Of course Rutan's people have it on the ball a lot better than that.