NASA space ship

HB of CJ wrote:OK young people ... listen up. I was a kid of 15 way back in 1961 and me and my family all gathered around the very small Black and White TV set watching Scott Carpenter blast off from Cape Canaveral in his Redstone rocket for the first USA sub orbital hop. The whole flight, (mission?) took a whopping 15 minutes.

I distinctly remember me thinking at that time ... "And we are on the way to the stars". Well, almost. Lots of reasons why. No point going through them here. But ... we will eventually get there ... one way or another. Maybe not back to the Moon for another 100 years, but we will be there then to stay. A colony.

Same thing with Mars. Maybe 200 years. A permanent large colony. We will go there, but it will take some time. It will have to be made cheap, quick, safe and simple. Kinda like the sailing/steamship era. RFC does a fantastic job reflecting future history with the Honorverse. Wow. Hang on. We will do it.

Flash forward about 5000 years and that private starship named Jennifer. "Jenn, where are you? Oh, there you are. You closed up and everything. You need maintenance? Oh, I forgot. One thousand credits? OK; you deserve it. Now we want to go to Terra Nova for vacation. (holiday) Three days? One way? OK.

HB of CJ (old coot) Cm. And that is the way it will be someday. But not today. I love this Excellent Forum.

I'm afraid that your memory is playing tricks on you. Scott Carpenter was the second manned sub-orbital flight of the Redstone (May 24, 1961). The first was Alan Shepard on May 5, 1961. And I remember watching both of them as an avid 13 year old.

The 1950's and 60's space program was a really different time. Some of the "accidents" you refer to in the NERVA program were deliberately caused by the test crew to assess possible failure modes (the idea of creating a failure on a computer simulation was decades in the future).

Of course they also did some other environmentally unfriendly acts like detonating nuclear weapons in the open air, dumping liquid Hydrogen, liquid Ozone and liquid Fluorine in the desert to see what would happen and how spills should be contained.

The main reason that the NERVA was designed to be the upper stage of a Saturn V stack had to do with the problem of erosion of radioactive fuel elements into the exhaust stream. Using the rocket in space made the problem moot, and as noted, provided a high energy stage for use in orbit and potentially interplanetary space. In principle there is no restriction to making a nuclear powered launcher (NTR's which have T/W greater than 1:1 are quite possible), but today politics would certainly be against such a launcher.

Tenshinai wrote:The reason noone is even trying to build your "space-going 747" is because we do not have the ability to build such a thing.

Bullshit. We have the ability to build a ground-to-orbit spaceplane today; we just can't do it the way NASA does things. I never said that it would look or work anything like a 747, just that it would have a similar operational profile: fly, land, reload & refuel, fly again. Do you seriously believe that the guided missiles we send into space today are in any way efficient, or practical? Is it not stupid that a satellite that will spend its entire operational life floating in microgravity has to withstand 6+ Gs and ferocious shaking to get there? Is it not idiotic to consume an entire billion-dollar rocket to put ONE payload into orbit? Think about that. You throw the rocket away piece by piece during the flight. What would air travel be like if you had to build a whole new plane for every trip, and carry passengers on what is effectively its test flight?. Commercial aircraft are designed to amortize their construction cost over 20,000 flights or more.

I have been aware of the requirements for getting into orbit for a long, long time. Of course you have to achieve orbital velocity; that is the very definition of "getting into orbit". There is just no reason that it has to be done in seven minutes, or vertically, or that you have to reach Mach 8 inside the atmosphere. These are simply the constraints imposed by the use of multi-stage rockets, which are about the worst possible way to move cargo from ground to orbit. We are using them not because they are efficient or practical, but because they were the fastest way for NASA to attain the single, limited and IMpractical goal of sending one man to the Moon, letting him walk around for a few days, and bringing him back. Sending two men was an overachievement. Sure, it was an impressive publicity stunt, but everything they built was nearly useless for any other purpose.

And reaching 26km altitude on airbreathing engines? I´ll believe it when i see it.

The SR-71, which you mentioned in the preceding sentence, did just that 50 years ago. In fact, a spaceplane would borrow heavily from SR-71 technology. Oxygen makes up 75% to 88% of a rocket engine's fuel mass. It is essential to use air-breathing engines to the limit of their capabilities; that outside air is not just oxidizer, it's reaction mass you don't have to haul along on-board.

My concept for a spaceplane that could be built with existing technology would look something like this.

Airframe:
A flying wing or lifting body design, instead of a wing-and-tube that concentrates stress at the point where they're stuck together. Total takeoff weight of the small, prototype version would be between 150,000 and 180,000 pounds, making it more of a space-going 737 than a 747.

Fuel:
Due to the many problems associated with producing, storing and handling liquid hydrogen, the most suitable fuel would probably be oxygen/methane, with oxygen/RP-1 as second choice.

In-atmosphere engines:
High-altitude turbine engines, something like the SR-71's J-58 from fifty years ago. The smaller, initial version could just use a pair of updated J-58s designed to run on methane or RP-1.

Orbital boost engines:
A pair of rocket engines with 70,000 to 100,000 pounds total thrust to take over when the turbines peter out. These would take about half an hour to reach orbital velocity. So what?

With smaller engines, lower acceleration and reduced stress, everything about the vehicle can be made smaller, lighter, cheaper and more reliable. It would have a fairly small payload capacity, but could easily carry a cargo to orbit every day for little more than the cost of fuel. Even if it can only deliver one ton, that's a ton every day for 1/1,0000th the cost of using rockets. Of course a lot of things can't be broken up into one-ton packets, but a lot of other things can, and after the concept is proven work can begin on the real "747" spaceplane with a takeoff weight of a million to 1.2 million pounds and 15 to 20 ton cargo lift.

Imaginos1892 wrote:Orbital boost engines:
A pair of rocket engines with 70,000 to 100,000 pounds total thrust to take over when the turbines peter out. These would take about half an hour to reach orbital velocity. So what?

So, what fuel and oxidizer supply do your system need to allow rocket engines work for half an hour?

Imaginos1892 wrote:Orbital boost engines:
A pair of rocket engines with 70,000 to 100,000 pounds total thrust to take over when the turbines peter out. These would take about half an hour to reach orbital velocity. So what?

If you use aerodynamic lift at high suborbital speed, you have a heat problem which is made worse by a longer in-atmosphere flight phase; with thrust lift you could climb vertically but a low acceleration eats additional fuel.
Runnung the theoretical numbers in a hurry, 100 000 pounds of thrust requires fuel at a rate of 120 kg/s (Methane/Oxygen, 3700 m/s exhaust), over half an hour this adds up to 216 tons.

Finally there is rocket performance: Excluding oddballs (H2/F2, H2/O2/F2), Hydrogen/Oxygen gives the best exhaust velocity (4700 m/s), cutting down the required mass ratio. For example, your 30 minute 100000 pound burn would "only" need 170 tons of fuel.

Would a launch system like this one be feasible?

Somewhat, although reaching orbital velocities requires rather large structures and a lot of power.

Imaginos1892 wrote:Is it not idiotic to consume an entire billion-dollar rocket to put ONE payload into orbit? Think about that. You throw the rocket away piece by piece during the flight.

And that´s the kind of thinking that caused the Spaceshuttle to turn from a "cheap" alternative into something VERY expensive.

And no, it´s most certainly not idiotic, because dropping spent pieces of the lifter means the remaining parts doesn´t have to provide the thrust to also lift the now useless parts as well.

Imaginos1892 wrote:Do you seriously believe that the guided missiles we send into space today are in any way efficient, or practical?

Obviously not, since the Russian single use rockets clearly did not outcompete the Spaceshuttles to a ridiculous degree when it came to placing cargo into orbit...

Heck, USAs own single use rockets outcompeted the shuttles with blatant ease as well.

Imaginos1892 wrote:What would air travel be like if you had to build a whole new plane for every trip, and carry passengers on what is effectively its test flight?. Commercial aircraft are designed to amortize their construction cost over 20,000 flights or more.

What would air travel be like if passengers had to pay for flying suborbitally every time?

Answer, it wouldn´t exist because almost noone could pay the cost, and those who could would be too few to warrant anyone building any such planes.

You clearly have no clue about where the problems actually lie.

Imaginos1892 wrote:There is just no reason that it has to be done in seven minutes, or vertically, or that you have to reach Mach 8 inside the atmosphere.

Why do you think military aircraft preferably makes use of air refuelling right after take off?

Because then they can both take off with less fuel in their tanks, as well as ignore the fact that taking off is the most fuel intensive part of flying.

Is that enough of a hint?

Imaginos1892 wrote:We are using them not because they are efficient or practical, but because they were the fastest way for NASA to attain the single, limited and IMpractical goal of sending one man to the Moon, letting him walk around for a few days, and bringing him back.

Yeaaahhh, lets see, ESA uses single use rockets, CNSA likewise, JAXA likewise, ISRO likewise, KARI likewise, ROSCOSMOS likewise(HAVE flown shuttles to orbit, but dumped them due to high costs), notice a trend?

Now then, how many nations operate a "space plane" lifter... None, zero. How many thinks such a thing is easier to build than single use rockets? Zero.

All attempts with shuttles died out due to high costs and long overhaul times between flights.

Imaginos1892 wrote:The SR-71, which you mentioned in the preceding sentence, did just that 50 years ago.

That is incorrect. Almost that altitude, but not quite. And it reached it at a speed that is less than half of what is needed.

And in case you missed it, the SR-71 became an almost "one-off" thing because it was hideously expensive to operate. And 12 out of the 32 built were lost in accidents. That´s not a good safety record.

Imaginos1892 wrote:In fact, a spaceplane would borrow heavily from SR-71 technology.

Not really no.

Imaginos1892 wrote:In-atmosphere engines:
High-altitude turbine engines, something like the SR-71's J-58 from fifty years ago.

Not nearly good enough, cant reach high enough speeds.

Imaginos1892 wrote:With smaller engines, lower acceleration and reduced stress, everything about the vehicle can be made smaller, lighter, cheaper and more reliable.

*sigh*

You just exchanged one form of stress for MORE of another. Why do you think i brought up the SR-71 and the MiG-25?

Because both had to be built very extremely to be able to reach the speeds they could.

Hello, the MiG-25 was built in high strength STEEL, because normal aircraft alloys can´t handle the heat and temperature differences.

The SR-71 fuselage isn´t even proper shape until the plane speeds up enough to cause the heat needed to expand the parts.

Imaginos1892 wrote:It would have a fairly small payload capacity, but could easily carry a cargo to orbit every day for little more than the cost of fuel.

That was pretty much how the space shuttle was meant to be.
Didn´t work. Not even close.

Take a look at readiness hours for SR-71 and MiG-25 and realise that what you´re proposing is considerably HARDER to achieve.

Imaginos1892 wrote:on the real "747" spaceplane with a takeoff weight of a million to 1.2 million pounds and 15 to 20 ton cargo lift.

15-20 ton? Not very useful when its heavy an superheavy lift capacity that is missing.

Michael Everett wrote:Would a launch system like this one be feasible?

Probably yes. It greatly reduces the amount of fuel needed, and should be both realistic and lower costs.

Initial investment is BIG however. And finding good places for the starting rail isn´t entirely easy. So still not a "quick&easy" solution unfortunately.

And thank you everybody. I wonder if Mr. Weber had any idea about what might happen here? I also am a big space fan and would gladly donate a size able percentage of my meager annual income for a world fund for aero space tech ... if it were to be $used$ wisely. Research?

Isn't it strange. I am an ultra cheapo libertarian who believes in the future. Have there been any good international studies that just blitz different good ideas on how to get tonnage into low and high orbit cheaply and safely? You guys are "light years" ahead of me. And much younger.

I also have NOT clicked on all the presented sites. Sorry.

HB of CJ (old coot) Lowly Cm. I love this Forum! Age 68.