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Lack of escape systems could haunt X-Prize

Posted by: Guest - Wed Apr 07, 2004 1:01 pm
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Lack of escape systems could haunt X-Prize 
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Post "Intact abort" is simply another way of saying LAN   Posted on: Fri Apr 16, 2004 12:49 pm
idiom wrote:
And jetision straight into the bottom of white knight?

There is a reason fighter jets have ejection seats and airliners don't. It makes sense in a fighter. A fighter pilot needs to eject about once a week.

Imagine a 747 coming into land and a passenger panics. Due to the laws of mob dynamics 300 people eject into the path of the jumbo thats coming into land 30 seconds behind it, 500 more people eject....

You can see why we let them slam into hills and just move on.

If you eject out of a Rocket that is malfunctioning on the pad you will be burnt to crisp when it detonates. Thats why you need an abort tower. But will adding an abort tower and an extra stage to accomodate it give designers and engineers more time to fix the exploding engine problem?

In aircraft saftey means self extinguishing redundant engines.

Proper saftey means developing tanks that explode in intelligent directions without destroyng the crew cabin. Its about making the crew cabin survivable at all stages of the flight.

To make the next stage of the stuff really work, we will need INTACT ABORT, where the whole thing comes home safe despite the Ozone tank making like the 4th of July.

And what are we to do about hijacking? These are big ticket people on board these flights. Or what of pilot error.

We need a lot of really cheap flights from a lot of suppliers globally to make losses acceptable. So the world doesn't grind to halt.


"Intact abort" is an oxymoron, or maybe just moronic.

The X-15 had an ejection seat and NOBODY worried about the pilot ejecting into the wing on the B-52. Why? For one thing, it was not a permanent part of the B-52. If the X-15 a major problem they could simply drop it.


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Post Why Armadillo is a favorite.   Posted on: Fri Apr 16, 2004 3:38 pm
This is a reply to Senior Von Braun's question about why Armadillo is a favorite.

I'm sure others could give better answers, but here are my thoughts.

Armadillo has inspiring leadership. I personally would love to write a super popular game, become rich, and spend my time working on cool projects like building rockets. I think many people (at least on this board) can identify with this.

Armadillo is more open about their progress than any other team. I love reading their updates every week. I'm sure people would get excited about other teams if they had any information to get excited about.

Armadillo's success would surprise many people. It's fun to root for an underdog (if that underdog at least has a chance).

OK, I invite other people to explain why Armadillo is a favorite in a more eloquent manner.

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Post Re: Why Armadillo is a favorite.   Posted on: Fri Apr 16, 2004 4:15 pm
Lepton wrote:
Armadillo's success would surprise many people. It's fun to root for an underdog (if that underdog at least has a chance).


They're losing. That's why I like 'em. I like RocketPlane even more, just because of the design (I'm partial to spaceplanes). Not that I'm hoping that Rutan will fail -- I wish him all the luck in the world (and out of it). But I'm an American, and we tend to have a thing for the little guy who's gettin' the snot beat outta 'im. 8)

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Post    Posted on: Fri Apr 16, 2004 10:40 pm
Although Armadillo will not win the X PRIZE, it has the simplest design of any X PRIZE competitor.

Rutan's flights are always very successful, but they require intensive prepration: casting the grain for the hybrid rocket motor, for instance. Rutan's company has around 100 employees, although not all of them work on the X PRIZE project.

On the other hand, Armadillo's avionics, engines, and electronics are so eimple that the team can fly the vehicle several times a day. The engines can be lit, turned off, and reignited with essentially no in-between work.

In that respect, Armadillo is like XCOR, the California rocket company that built the EZ-Rocket that could fly several times a day.

I think that the Armadillo approach will prove superior in the long run, although Rutan clearly has the short-term lead.


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Post    Posted on: Sat Apr 17, 2004 12:49 am
The Legionnaire wrote:
<!--look up, you lazy bastards-->


Personally, I think spaceplanes have an even greater long-term advantage, as they can use conventional airports and do not require the recovery systems of a vertical rocket. Of course, they're necessarily a good deal less efficient, but for orbital work they're far superior to a conventional rocket due to their controllable landing.

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Post    Posted on: Sat Apr 17, 2004 1:41 am
The Legionnaire wrote:
I think that the Armadillo approach will prove superior in the long run, although Rutan clearly has the short-term lead.


Huh? No, I don't think that there's any way that could be possible. Armadillo is following the kind of approach that yeilds products like monowheels that move at up to 57 mph. They're interesting oddities, and work, but don't really have an commercial market. Just look at Armadillo's approach. They're buying off-the-shelf components from across the board, which is fine up untill you try to mass produce something. Just try getting all of those companies to suppply you what you need to make a bunch of Armadillos. Scaled Composites, on the other hand, is working deals out with contracters they know, in a heartbeat they could spring into full mass-production of the SS1 system.

Now, as far as actual vehicle layout goes, a hybrid of the two would actually be ideal. I agree with Space Cowboy that rocketplanes are the way to go, but the hybrid motor just isn't as good of an idea. Once it's started it can't be shut down or throttled, which can be disasterous in events like Challenger's last flight. Had they been able to shut down the malfunctioning SRB that would have been problem solved instead of a blown-up Shuttle. Granted, there were far more things going wrong as well, such as the disobeying of the Shuttle's launch temperature requiremnets, but the point remains that liquid propellants do have a clear advantage. The original layout of the Armadillo, with hydrogen peroxide monopropellant engines also had the edge of being non-polluting, though H2O2/Methanol doesn't sound as clean to me. However, the flight profile of Armadillo is just ludicrious. They're trying to launch the thing up to X-Prize altitude, keep the engines running the whole flight, and then land under more power. I don't even know if that's accurate anymore, they keep changing there vehcile, but that particular profile is very inefficent and sets itself up for disaster. What happens when the engines stop working? :shock:

Come to think of it, what does Armadillo have to do with abort systems? It's funny the way topics get derailed and resent on a differnt tangent like that.

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Post    Posted on: Sat Apr 17, 2004 2:12 am
Senior Von Braun wrote:
I agree with Space Cowboy that rocketplanes are the way to go, but the hybrid motor just isn't as good of an idea. Once it's started it can't be shut down or throttled, which can be disasterous in events like Challenger's last flight. Had they been able to shut down the malfunctioning SRB that would have been problem solved instead of a blown-up Shuttle.


Okay, correction necessary here (before I go sleep). SRB == Solid Rocket Booster. "Hybrid Rocket" != "Solid Rocket". A "solid rocket engine" is another way of saying "really overgrown firecracker". A hybrid engine, on the other hand, is a rocket that uses (usually) a solid propellant and a liquid oxidizer (or a liquid propellant and a solid oxidizer, basically the same difference either way). A hybrid can be shut off and throttled just like a liquid can, and has access to some super-high-efficiency fuel combinations that liquids don't. Hybrids are basically acknowledged as the (slightly-more-expensive) way to go.

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Post    Posted on: Sat Apr 17, 2004 3:03 am
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Had they been able to shut down the malfunctioning SRB that would have been problem solved instead of a blown-up Shuttle.


Actually, I'm pretty sure the disaster would still have occurred. The amount of dead weight and the resulting asymmetric thrust would doom the vehicle.

Interestingly, the Saturn V was built to avoid this problem: by placing all the engines for each stage close together and feeding from the same fuel tank, an engine shutdown (like on Apollo 13) would not cause any real problems. This strategy is being emulated by Elon Musk with his new Falcon 5 vehicle.


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Post    Posted on: Sat Apr 17, 2004 9:47 am
Aramdillo can scale up directly to orbital craft. Scaled may find that a tad trickier.

Mono propellant liquid engines are inherently unsafe as well. Hydrogen Peroxide is not the most fun thing to play with.

Scaled's Hybrid however is detonation proof.

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Post Hydrogen peroxide rockets are EXTREMELY safe   Posted on: Sat Apr 17, 2004 3:42 pm
They are SELF DAMPING. Too much fuel or too much combustion chamber pressure and the incoming fuel flow simply drowns the catalyst pack instead of producing a catalytic reaction.

Add to that the fact hydrogen peroxide is nontoxic and that's why hydrogen peroxide rocket cars remain the only type of rocket ever approved by the NHRA to run in front of spectators.

In over ten years of running at NHRA tracks, there were no major propulsion system mishaps.


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Post    Posted on: Sat Apr 17, 2004 4:33 pm
I find it very interesting how there is a lot of disagreement over what design is the best. Spaceplanes or VTOL? Hybrids or liquids? Powered landing or parachute?

In fact, this debate illustrates the power of the X PRIZE: the superior vehicle design is determined by actually flying different designs, rather than trying to determine which design is better using theoretical arguments.
Or, put another way, "The best design is determined by flying, instead of talking."


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Post    Posted on: Mon Apr 19, 2004 1:15 am
The Legionnaire wrote:
the superior vehicle design is determined by actually flying different designs, rather than trying to determine which design is better using theoretical arguments.


Yes, this is the beauty of the X-Prize, it's actually a lot like Darwinian evolution while groups like NASA work the way evolution is misconcieved as working. It's survival of the fittest, new ideas come up rather randomly, and the best ones are the only to survive, thus passing their genes for future generations. Except in this case, we're talking about rockets rather than dinosaurs. :D By contrast, NASA thinks up a plan and goes with it, which is great except that you can never know if that plan you used is the best.

As for Space Ship 1's engine, I'm not exactly sure how it works. I mean, I know the technology behind how it works, you spray really hot nitrous oxide onto HTPB, but I had heard somewhere that its engine wasn't throttleable or able to shut down. Maybe this was just a crappy source.

Perhaps I was exadruating when I said that had Challenger been able to shut down the problematic SRB it would have been problem solved. I never meant that the crew would reach orbit, rather they'd have to shut down both SRB's, then detach from the main fuel tank. Provided you did that at about 40,000 feet and 500 mph (Wasn't that about how fast they were going?) you'd have plenty of room to come back to the Cape for a landing. That certainly is a much better outcome than seven dead astronauts.

One final thought, Armadillo isn't really suited to scaling up their vehicle either. They're not going to be able to keep the powered landing system, it'd be melted off during reentry unless they make some major design changes. Also, their problem, like I said earlier, is that they have a rocket practically built by eBay. Who knows how many sources the parts came from? And they'll need much more efficient engines for their lower stages.

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Post    Posted on: Mon Apr 19, 2004 1:36 am
The aramadillo would make a perfect reusable booster stage.

Unlike the Space shuttle, the booster should be reusable and the orbiter should be the first to become expendable. Armadillo with a capsule on top.

Also the Saturn V first stage only had an ISP of 280. 7.5 million pounds but only at 280.

They do have sourcing issues, but that is the easiest problem of all to resolve. If theres money then there is supply. Supply is dodgy at the mo, because there is no money.

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Post    Posted on: Mon Apr 19, 2004 4:35 pm
Von Braun, I think you have a misconception about the way that manufacturing works.

Off-shelf = cheaper, and quicker availability.

The more volume, the cheaper it is and since you're sharing volume with other users....

If you buy off-the-shelf parts, you don't re-invent the wheel, you don't have to tool up, you save time, and it's going to be cheaper than building custom parts for everything. Also, you already have a continuing source of product. If and when Armadillo comes up with a working design, they will be able to crank out rockets much more quickly and cheaply than Scaled.

The trade off is that the parts will weigh more and not be designed for a rocket which could cause big problems.....


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Post    Posted on: Mon Apr 19, 2004 9:25 pm
j96 wrote:
If you buy off-the-shelf parts, you don't re-invent the wheel, you don't have to tool up, you save time, and it's going to be cheaper than building custom parts for everything. Also, you already have a continuing source of product. If and when Armadillo comes up with a working design, they will be able to crank out rockets much more quickly and cheaply than Scaled.


Sorry, we're getting off the topic of escape systems so I'll be brief.

There is a very useful model in business strategy called Porter's Five Forces. Basically it states that the competitiveness of a business is shaped by five forces, the strength of buyers, the strength of sellers, the available substitutes, entry barriers and industry competition (rivalry).

The idea to achieve a competitive position is to maximise control over these factors, ie build barriers to new entrants and sell to many seperate buyers so they can't group together and manipulate price.

The issue here is the suppliers. If Armadillo buy off-the-shelf then they may end up being completely dependant on a particular product or even worse a particular supplier. This causes two risks:

(1) If the supplier realises their strength, then they can manipulate price, and if Armadillo have no choice but to buy, then they're screwed.

(2) If the supplier they're buying from goes bankrupt or stops that product line, what happens? Armadillo can't maintain or build any new rockets.

I'm not saying that designing and manufacturing your own parts is the only option, as this has very strong disadvantages, but off-the-shelf should not be considered as a panacea for all woes.


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