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Another Clueless Commentator

And the sad thing is that he thinks he's smarter than those of us in the business. Clark Lindsey has a rejoinder in his comments section. I will add that this doesn't inspire confidence in his analysis:

SpaceShipTwo actually will only barely scrape space, eking out a scant 68 vertical miles before succumbing to the gravitational dominance of Earth. The craft musters only about 1/16 the energy needed to reach even low orbit 100 miles up. The space station, reposing 200 miles from the earth's surface, is completely beyond reach.

Attaining such distances requires enormous energy...

No, it's not the distance that's the problem, it's the velocity.


And Jeff Foust has found another idiot who wants it to be made illegal on environmental grounds. And because it's "selfish."


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K wrote:

I take it that it's a slow day news wise. The normal blogger drill for this is to find another blog where the owner has managed to post something either outrageous or just plain stupid and rag on them for a while. It must be truly slim pickings today that you've gone down to the blog comment level looking for idiots to fisk.

As a confirmed "idiot" comments poster myself, I submit that it's beneath a competant blogger to go searching for stuff to attack in the comments section of other people's blogs. I enjoy sticking my 2 cents in and usually that's what it's worth. Maybe sometimes I happen to have some special knowledge or perhaps I'm even mentally coherent that day and say something bright. But on the whole, I don't want to worry about my comments being made the subject of derision over the blogosphere because it's a slow day.

The exceptions to this are particularly vicious or violent postings, or fisking comments on your own site. But common garden variety dumbness or ignorance on other people's blogs is not only of low information content, it tends to make the casual poster like myself less interested in reading the blogs that indulge in it.

john hare wrote:

I will make a prediction.

Within ten years of reliable suborbital operations, frequent reliable orbital service will start.

My reasoning seems simple to me.
By the time suborbital craft can turn around multiple times per day, reliable engines, regulations, airframes and operational procedures will be well known. Except for reentry, orbital is just bigger and more of the same.

A canoe builder might not be able to build a trans Pacific ship. A yacht builder can.

K wrote:

Yay! I prove my own point by assuming that "commentor" means comments section in a blog.

"Never mind".

Now excuse me while I go find something lowest common denominator to watch on TV.

brian d wrote:

No, it's not the distance that's the problem, it's the velocity.

Or more specifically velocity squared, but It's really both (mgh + 1/2 mv^2 in very simplistic terms), which is why he mentions energy,
and a factor of 16 is too low (more like 20-25). That's the real metric. SS2 will be a factor of 20 or so short of orbit in all the important ways, cost especially.

john hare wrote:

The skills, infrastructure and experience are more important than the actual energy involved. Once you know how to build a car properly, building one with a bigger engine and fuel tank is not nearly as difficult.

Karl Hallowell wrote:

brian, no it is simply velocity. I don't know why people insist on focusing on the energy when that's not a major problem. I guess saying incorrectly that a problem is 20 times more difficult sounds sexier than noting it's actually a bit over 4 times as difficult.

And you're extrapolating from energy to claim that cost will also be a factor of 20 short? Please. You have no grounds to base that judgement on.

Paul F. Dietz wrote:

Focusing just on energy is also simplistic, since the energy efficiency of a rocket propelled vehicle depends on the total delta V. If the mission delta V is small, but the rocket exhaust velocity is large, almost all the kinetic energy in the rocket exhaust is wasted, and overall energy efficiency is low. If I recall correctly, ebergy efficiency is maximized (ignoring drag and gravity losses) when the rocket exhaust velocity is 61% of the mission delta V (for a single stage system with constant exhaust velocity).

Rand Simberg wrote:

Yay! I prove my own point by assuming that "commentor" means comments section in a blog.

Note that I wrote "commentator," not "commenter."

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This page contains a single entry by Rand Simberg published on August 2, 2008 12:29 PM.

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