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Comment Unreasonable Rocket - 2011 (Score 1) 55

Paul Breed was 3D printing liquid fuel rocket motors in 2010 and was test firing them by 2011. His test firings also took place at FAR, the same facility mentioned in this article.

Here is a link to Paul's blogs that (somewhat) relate to his experiments with printed engines:
Unreasonable Rocket

I believe that he beat NASA and everyone else out of the gate with this technique.

Comment Re:Will it be "most powerful" by time of launch? (Score 1) 251

interesting, thanks for the reply. I forget that mass to an orbit is a factor of more things than thrust.

On the cost issue, I have to think his costs have been higher than expected because 1) he probably didn't really envision the massive staff and infrastructure that he is currently bankrolling, and 2) what must be spiraling r and d costs. I would guess that he is pricing them not based on cost but as high as he can and still be cheap enough to capture and grow the market.

Comment Re:Need More Science (Score 0) 243

"once fuel runs out, you just fall to the gravity well."

The same could be said of virtually any powered aircraft. The length of time that they can spend 'aloft' is limited by the amount of fuel that they can carry. It's besides the point.

"If you're in the atmosphere, you can glide without using all that much fuel. You can't do that in space - certainly not at 100km altitude. In order to 'stay afloat', you need to do orbital velocity."

That's the issue; as long you're making enough power to overcome gravity, you can 'stay aloft' at any altitude, and you definitely don't need orbital velocity to do so. Orbital velocity is the speed needed for an unpowered craft to remain in orbit. It has nothing to do with a rocket plane flying around at 100m or 200km. Postulate a rocket plane big enough to hold the required fuel and nothing would stop it from flying up to 200km, maneuvering around 'aloft' for an hour and then flying back down.

"Of course, since it's not like atmosphere abruptly ends somewhere, the 'where to draw the line' can be a bit arbitrary, but the currently chosen one isn't impractical."

I never argued otherwise.

Comment Rockoons are over 60 years old (Score 2, Informative) 243

I have to disagree with your statement that ARCA is doing something 'genuinely innovative' by using a balloon for the first stage. The concept is called a 'Rockoon' and was pioneered in the US in 1949 and has been used extensivly by JP Areospace, (among others), a small US company that has been working with balloons and rockets for over 30 years.

Comment Need More Science (Score 2, Informative) 243

At 100km in an aircraft, you need to fly at orbital velocities just to stay aloft, so effectively you need a spacecraft instead.

What??? Sorry, you need to go back and rethink that statement; it's not even close to true. Can you explain how SpaceShipOne, flying at 'only' Mach 3, was able to go higher than 100km? Thus, not only staying aloft at at 100km, but climbing? Or the X-15, which also flew higher than 100km, and also at significantly less than orbital velocity?

I like how a good authoritative sounding statement, (which happens to be false), got modded +4 informative.

Comment Re:Sad, actually (Score 1) 285

Why all of the unfounded pessimism? Are you people completely unaware of how many rockets we launch into space every year?

nobody that knows anywhere near as much about rocket engines left.

Then who the hell designs and builds the rocket engines for the Ariane, or the Atlas, or the Delta, or the Falcon, or any of the half dozen or so other heavy lift rockets in operation or development around the world?

While the main engines for the Shuttle are somewhat of a marvel, I doubt they could be reproduced today either. The people resources simply aren't there - it would take 10 years of experimentation and learning about rockets.

What?? How do you think they refurbish them after the missions if they don't understand them completely? How was Rockwell able to build a new shuttle in the early 90's, including rocket engines, if no one is left? That space division, now owned by Boeing, still designs and builds new rockets. How can that possibly be?

Comment Not a Formal X-Prize Competition Yet (Score 1) 285

I was surprised (naive, I know) that the link in TFS was not to the X-Prize website, so I went looking for it.

It turns out that deep ocean exploration is only one of several contending future exploration X-Prizes.

Is this an attempt to stack the deck in Cameron's favor by forcing the competition choice through publicity as if it's a forgone conclusion, and meanwhile he has maybe a six month head start on the competition?

Comment Getting our eggs into another basket (Score 1) 285

You too should read "The Case for Mars". There are many reasons for colonizing Mars, not the least of which is as an offsite backup for humanity.

Other reasons range from the practical; with Mars as source of rare elements not available in sufficient quantities on Earth, to the esoteric, with the new Mars frontier providing the challenge that humanity needs to hone its pioneering edge.

Comment The Moon is not good for staging Mars missions (Score 1) 285

You should read the book "The Case for Mars". It does a really good job about laying out all of the issues and technologies related to establishing a manned presence on Mars.

To summarize one of the points; there is no reason to go to the Moon first as a staging ground for Mars. Quoting from the Wikipedia article:

"In the same chapter, Zubrin decisively denounces and rejects suggestions that the Moon should be used as waypoint to Mars or as a training area. It is ultimately much easier to journey to Mars from low Earth orbit than from the moon and using the latter as a staging point is a pointless diversion of resources. While the Moon may superficially appear a good place to perfect Mars exploration and habitation techniques, the two bodies are radically different. The moon has no atmosphere, no analogous geology and a much greater temperature range and rotational period. Antarctica or desert areas of Earth provide much better training grounds at lesser cost."

Comment Stop Feeling Sorry (Score 1, Flamebait) 285

To clarify: I find it a bit sad that humanity just isn't capable of building on pre-existing accomplishments, solutions and ideas..

What the hell are you talking about? What do you think fuels our continuing huge advancements in science, and well, everything from manufacturing technologies to medicine? Building on pre-existing accomplishments, solutions and ideas, that's what.

Sort of like the Apollo program - almost half a century after, we are not capable to go to the Moon - we simply and stupidly "forgot" how to do it. The great designers and engineers left and/or died off, and we, as humankind, went on with out collective dicks in our collective hands.

When you hear stories talking about how we lost the technology to rebuild the Saturn V rockets that were used last time, it's absurdly shortsighted to interpret that as meaning that humanity can't go to the Moon. We are sending unmanned missions there all the time; the only thing keeping manned mission from returning are other budget priorities.

Yes, we would probably have to relearn some of the manufacturing steps involved if we wanted to recreate the original rocket designs exactly, but why the hell would we want to do that? It's 50 year old technology that we no longer care about. We also can't build giant stone pyramids as well as we used to be able to, but does that stop us from building modern cities?

Take your hands out of your pants and go get an education.

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