New Space Race - Private vs. NASA

Rxke · 2004-04-26 10:56:38

Hmmm... to be scrapped from Soyuz 'Tourist Edition'

-docking adaptor and related electronics
-extensive in-orbit manouvring capabilities
-6 month's worth of batteries
-Solar panels (?)
-...

Might add up to a very signifivant amount...

But, come to think of it, have you ever seen in-flight pics of a Soyuz cabin? VERY cramped, so i dunno a 3 day holiday will be all that luxurious...

Autopilot? Potential big weight-saver, but I think that'll be asking for troubles, regulations-wise, and a breveted pilot would be a nice extra, on-board, saves the tourists from a lot of stuff they'd have to learn/do themselves...

clark · 2004-04-26 11:03:18

Well, people going into space aren't looking for luxuary... the same way people going off to the North pole aren't looking for a day at the beach. Sure, some may want that, but the destination is the point, not the stuff in between.

The whole autopilot is negotiable, but take the 747's- they fly themselves. The Shuttle flys itself (the only thing the astronauts really have to do is lower the landing gears). But hey, I'ld like a pilot on something like this, if for no other reason than to assure me that all those sounds are normal.

Rxke · 2004-04-26 11:25:33

The spam-in-a-can autopilot vs. Hot space Jockey...

I guess for tourists, being not professionals, a pilot will prove invaluable... AND said pilot can get his flying-miles, if he later wants to promovate (sp?) to a 'bigger' job in that tourist industry, (say, longer cruises, or a 'calmer' job (as he/she gets too old for all that excitement) for example an entertainer in the zero-gee bubble of the newfangled hotel... he'll be first in line: highly-trained, used to zero-gee, and maybe very important for the 'good feeling:' used to coping with rich, pampered puking newbies in space etc...

GCNRevenger · 2004-04-26 11:29:45

But you have to think big, there isn't any other way... The problem is for a given fuel you can only deliver a certain percentage of the total vehicle weight to orbit. Since this percentage is small (about 3% for man rated Soyuz) and since a manned space vehicle will be fairly heavy, then the rocket must therefore be quite large. This is not somthing that can be "ingenuitied" away, a few percent is about all you get with LOX/RP1 fuel with a small rocket. Chemistry dictates that you get only so much energy per pound of fuel (without melting the engine) and physics dictates that you need a certain amount of energy to overcome gravity and inertia.

The Souyz R-7 rocket, which has no provision for reuseability, costs $40 million dollars each, weighs 300,000 pounds, and stands 150 feet tall in order to loft 15,900lbs Soyuz vehicles, plus is fully developed already. Making a reuseable rocket will be difficult, and I don't think its practical to reuse the upper stage at all, which will be particularly expensive on a per-flight basis. Again, I would like to point out that making and flying space expendable vehicles is an expensive business even with unlimited demand, especially ones which must be man-rated, and will not become "super cheap" even if you build alot of them.

This is a principle of economics, that the effect from increased demand exsists over a range from essentially zero cost reduction to prices which are only just above the expenses. Unfortunatly, expendable vehicles lean far tward the former, and making 100 rockets as opposed to 10 doesn't make much impact in the cost of those delicate rockets engines and the precision engineering.

The Soyuz vehicle is already about as bare bones as you can get... it doesn't have six months of batteries, it remains shut down when at the ISS, the six-month thing is because of its nasty hypergolic fuel can eat the engines over time. Docking hardware and solar pannels aren't a signifigant mass, nor does it carry alot of OMS fuel. If anything, I would aim for a bigger vehicle, able to seat four and be long enough to stand up perpandicular to the heat shield plus a foot or two.

I would say that such vehicle, especially one designed for "cheap dumb ruggedness" and reuseability would weigh in at 20,000lbs, which would give you headroom for weight creep (or heavy tourists), more volume, and extra safety features... Soyuz capsules throw away the engines, tankage, main batteries, solar pannels, and orbital module, everything basicly to save on reentry weight. I would want to at least save the upper stage guideance, RCS thrusters, electrical/navigation, and the extra pressurized volume.

clark · 2004-04-26 11:39:56

GNC, I respectfully challenge the premise that launch costs cannot be reduced through gains in the production side. Perhaps it is wishful thinking, but I look to some of the alt space crowd that says improvements can be made, and that other avenues exsist to bring the launch costs down. What you are repeating makes sense, but it is also the claim made by every large aerospace concern today.

I think making a capsule larger is a great idea- as long as it is designed to accomadate a multiple number of rocket types. Then, a company can shop around for the best price for their orbital vehicle, or launch multiple ones at the same time on a number of different launch architectures.

I still don't see anything that would prevent this type of pursuit...

Palomar · 2004-04-26 12:50:44

*The "new space race" is: A lot of lip service.

Mostly all talk and very little action.

--Cindy

clark · 2004-04-26 12:52:34

Sounds like a 900 number...

Rxke · 2004-04-26 13:26:21

I tend to disagree, Cindy...

We have two things going on, in tandem: X-Prize and Elon Musks Falcon vehicule... (and a lot of others, but let's simplify)

Rutan's proven it is possible (X-Prize stuff) OK he didn't do 100km, twice in a week, but he'll get there shortly. All but surely.
He said he's not going to commercialise it, but his backers (Allen) might think otherwise.

So, expect SO paying tourists around 2005-6

Falcon: a (lightweight) rocket, built for around a 100 million, possibly reusable in a degree, not flown yet, agreed, but already customers. So there is a (small) market.

Expect it to fly by 2006

In the wings: bigger FalconV, unofficially, Elon's talking about manned launches... Timeline: already fairly far in developement, some say 2007, might be overly optimistc, before knowing what it's little brother will do...

I think some big time touristcompany movers and shakers are following this very closely. There are *a lot* of people with big wallets and stars in their eyes... that would happily pay for a spaceride.

Palomar · 2004-04-26 15:18:52

So, expect SO paying tourists around 2005-6
I think some big time touristcompany movers and shakers are following this very closely. There are *a lot* of people with big wallets and stars in their eyes... that would happily pay for a spaceride.

*Watching people take joy rides in space like an LEO carousel ride for the next 2 to 3 decades. Sorry, I'm not interested. :down:

I'm more interested in just getting to Mars, period.

By the way, what's the difference between a scramjet and a ramjet? None, that I can tell (I've seen both words used in an article about one of them!) Why the little discrepancy in spelling?

--Cindy

Ian Flint · 2004-04-26 16:50:22

A ramjet can go up to about mach 5 max.

A scramjet can go up to mach 10 - mach 20 they say.

I think the "sc" in scramjet is supposed to imply "supersonic" even though a ramjet can already go supersonic.

Mark Friedenbach · 2004-04-26 20:39:29

sc - supersonic combustion

EDIT: cindy, the technology behind the two is very different. i don't have time to write now, but i'm sure you can find a good description of the two with a google search. ramjets are used by all supersonic jets, only two scramjets have flown (the nasa hyper-x and the australian project a year or two ago)

Hazer · 2004-04-27 01:25:48

Yes Cindy, I know you want to go to Mars. Heck, I want to go to Mars, if you know someone who is selling tickets-please tell me.

But can we really expect NASA or any of the world's space agencies to suddenly wake up one day and say, "We're going to put <your name here> within the next five years"?

The reason some of us (myself included) tend to be gung-ho about the whole suborbital tourism thing is that it IS a step. It brings space-access, and Mars by extension, one giant step closer to the common folk like us. Essentially, trying to develop cheaper, or more widespread access to Space via X-prizesque vehicles is equivalent to the Mars society simulating a Mars habitat out in the desert.

Neither task gets us much closer to Mars, but we are putting what we have learned from NASA and from our own research to the test.

And who knows if the Suborbital joyriding won't turn into something more? If anything, it'll generate -revenue- and perhaps shock some of the larger companies such as Lockheed or Boeing into the Spacecraft market. Why does no one make passenger spacecraft for paying customers? Because there is no -market-

If suborbital joyriding ignites a market for passengers, I think their goals of altspace NGOs will have been more then accomplished. If they make a profit off of it, so much the better-perhaps they will then have some capital to invest in going orbital and not need as much financial backing as one would now.

As much as some of us would like to believe otherwise, the public perception has a great deal to do with how successful a political or business venture is. NASA should be especially aware of this.

This is why you should never stop arguing in favor of going directly to Mars (Or whatever your position is, I don't claim to know you well enough), and it is why I will never stop arguing in favor of the altSpace NGOs: the public perception can drive reality.

And besides that, I have a bet going with a friend as to who will get past the official boundary of Space first. Last one up is a rotten egg.

Algol · 2004-04-27 10:41:11

In a ram-jet the incoming air is slowed to sub-sonic speeds before ignition to produce a supersonic exhaust and thus travel at supersonic speeds. Scramjets have a slightly simpler design (which hides the fact that they are far more complex in reality for various reasons) but they dont slow down the exhaust to sub-sonic speeds, the air is combusted at supersonic speeds, hence supersonic combustible ramjet.

Heres a link which quickly explains it better than I.

http://www.aviation-history.com/engines/ramjet.htm]The Ramjet/Scramjet Engine

Palomar · 2004-04-27 12:27:02

*Thanks guys. I http://www.newmars.com/forums/viewtopic … 60]created another thread early this a.m. for the question. Algol and I are apparently thinking a bit alike today...(same link)

--Cindy

RobertDyck · 2004-04-27 21:01:40

Hi Cindy. I did reply on your new thread, but since everyone else is replying here, I repeat myself but with more detail.

A RAM jet uses a shaped intake to literally ram air into the engine. A turbojet engine uses a compressor to suck air into the combustion chamber, and a turbine to capture energy from exhaust leaving the combustion chamber. This means rotating blades in front and more rotating blades behind. One trick is to ensure there are fewer rotating blades behind to ensure the gasses go out the ass end. However, a ram jet is just a shaped tube with a fuel injector. The shape on the intake compresses air and slows it down below the speed of sound, then fuel is mixed with air and burned. The exhaust flows out the back end. The trick is to ensure the vehicle is travelling at the speed of sound, or close to it, before starting the engine. That creates a sonic-boom style shock wave in the intake. That shock wave ensures the exhaust goes out the back and the engine is pushed forward. You see, a ramjet literally rams air into it.

The problem with a traditional ramjet is that the air inside the engine must flow slower than the speed of sound. If it flows faster than the speed of sound you have two problems. First and most importantly, traditional jet fuel does not mix with air; it just flows unburned out the back of the engine. You must mix fuel with air in the combustion chamber to ensure burning fuel heats the air to create gas expansion. That expanding gas provides the force that is directed into thrust. No combustion, no thrust. Secondly, if you don't slow air from supersonic speed to subsonic speed then how do you ensure thrust is applied to the engine rather than just pushing air out the front?

A Supersonic Combustion RAM jet (S.C.RAM jet) works by letting air inside the engine flow faster than the speed of sound. Shaping the compression waves to ensure thrust and not just pushing air out the front is tricky, but has been done. Ensuring fuel mixes with air so it can burn before flowing out the back is more difficult. One means is to use liquid hydrogen fuel. Pipe the liquid hydrogen around the engine to cool it; that prevents the engine from melting. It also pre-heats liquid hydrogen so it boils into hydrogen gas. Hydrogen gas mixes easily with air, so ensuring it burns before flowing out of the engine is not a problem.

The limit of a traditional ramjet or turbojet engine is slightly faster than mach 3. Rumour says the SR-71 Blackbird was able to fly at mach 3.6 with its turbojet engines. Airline aircraft use a fanjet, which is a turbojet engine with an oversized compressor that lets some air bypass the combustion chamber. Ever notice the cylinder in front of the engine is larger than the cylinder in back? That is because the compressor just pulls some air and lets it slide along the outside of the combustion chamber, effectively pulling the aircraft forward like a propeller. But unlike a propeller, all the air is directed backward, which directs thrust forward. A propeller lets some air slide straight out to the side away from the propeller axle, by centrifugal force. That directs thrust opposite, but it's sideways and in all directions at once; thrust from one side of the propeller cancels the other. A ducted fan is more efficient than a propeller and the air from the compressor that isn't directed into the combustion chamber is the same as air through a ducted fan. But why is a fanjet more efficient than a turbojet; I don't know.

The X-43A was designed to fly its last mission at mach 10. NASA flew the last test without a parachute so they can't fly another test flight. We will never see it fly mach 10. If the SR-71 can fly mach 3.6 and it is the fasted turbine jet powered aircraft, that give you some idea of the capabilities of a SCRAM jet engine. The Space Shuttle enters the atmosphere at mach 25, so if it could leave the atmosphere at mach 25 it would drift to orbital altitude where a small burst from its onboard OMS rocket engines could insert it into orbit. Air is so thin in the upper stratosphere that energy between mach 10 and 25 isn't that great. Furthermore, a few aerospace engineers have told me that the mach numbers are not linear. That means the difference between mach 1 and 2 is great, but the difference between mach 21 and 22 isn't.

The ability to fly without carrying oxidiser for the lower stage would GREATLY reduce the weight of the spacecraft. The SR-71 Blackbird flies at about the maximum speed you can go on an air breathing engine without using supersonic combustion. A Supersonic Combustion RAM jet (SCRAM jet) would permit a spacecraft to go most of the way to space using an air breathing engine. That would permit a spacecraft the size of a 747 to take-off and land from a runway of any airport in North America while carrying as many passengers as small 737 used by United Airlines for domestic flights, although passengers would be limited to carry-on luggage.

GCNRevenger · 2004-04-29 11:44:36

Ah but NASA has one more X-43 for a Mach-10 test...

Ultimatly, an airbreathing engine or the advent of a metastable fuel (like radical liquid hydrogen) is the only way to get small easy-to-fly spacecraft into space without some crazy contraption like a cannon or moutain sled. Getting rid of the majority of oxidizer and switching to slush LH2 for airbreathing or making a new megafuel would reduce vehicle size and mass to a fraction of Shuttle for substantial payloads. In the mean time though, LOX/LH2 may provide enough performance for a light cargo or people hauler like the DC-X, but it isn't clear if such a vehicle can be kept light enough.

As for a manned orbital vehicle in the mean time, I don't think its practical to make it compatible with multiple launchers, since its alot of trouble to integrate different vehicles. Switch the booster, and you have to redo the flight control system and re-man rate the whole thing.

I'm sticking to my assumption that rockets are too hard to make for economies of scale to do much good, considering the lousy mass fraction that rockets have.

Mars_B4_Moon · 2022-07-25 16:15:52

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#51 2004-04-26 10:56:38

Re: New Space Race - Private vs. NASA

#52 2004-04-26 11:03:18

Re: New Space Race - Private vs. NASA

#53 2004-04-26 11:25:33

Re: New Space Race - Private vs. NASA

#54 2004-04-26 11:29:45

Re: New Space Race - Private vs. NASA

#55 2004-04-26 11:39:56

Re: New Space Race - Private vs. NASA

#56 2004-04-26 12:50:44

Re: New Space Race - Private vs. NASA

#57 2004-04-26 12:52:34

Re: New Space Race - Private vs. NASA

#58 2004-04-26 13:26:21

Re: New Space Race - Private vs. NASA

#59 2004-04-26 15:18:52

Re: New Space Race - Private vs. NASA

#60 2004-04-26 16:50:22

Re: New Space Race - Private vs. NASA

#61 2004-04-26 20:39:29

Re: New Space Race - Private vs. NASA

#62 2004-04-27 01:25:48

Re: New Space Race - Private vs. NASA

#63 2004-04-27 10:41:11

Re: New Space Race - Private vs. NASA

#64 2004-04-27 12:27:02

Re: New Space Race - Private vs. NASA

#65 2004-04-27 21:01:40

Re: New Space Race - Private vs. NASA

#66 2004-04-29 11:44:36

Re: New Space Race - Private vs. NASA

#67 2022-07-25 16:15:52

Re: New Space Race - Private vs. NASA

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