NASA space ship

Joat42 wrote:
The nuclear version considered as part of the Saturn V would have increased LEO delivery from 127t to 155t.
A later model would have upped that a bit more.

IF it worked. IF it worked reliably.

Simple truth is that most of the shouting about this stuff, like Project Orion etc, is mostly hype, because it was never finalised into a finished working model. At most there were some coldfiring tests and not a lot more.

That's not entirely true. The NERVA program for example was a success, the latest iterations of the engine worked reliable and NASA was in the process of designing a vehicle around it when the political backing for it disappeared due to various reasons.

If the development of NERVA had continued we probably would have a quite large permanent presence on the moon today among other things.[/quote]

A low cost S>O would be excellent. For nuclear, take a look at project Dumbo. NERVA was never designed to get 1g+ acceleration. For chemical, I'd start with an oxygen breathing first stage and possibly 2nd stage, as high and mostly fast as possible. These could be horizontal take off and landing, ie. airplanes and the final orbital stage a rocket. My reasoning? Calculate the proportion of fuel weight that is oxidizer. Even if it is only practical to reach Mach 1 and 30,000 feet, you have some velocity and are now above most of the atmosphere. If they get the SCRAMjet working, it should be possible for an air breathing 2nd stage to reach mach 7 or so.

DDHvi wrote:A low cost S>O would be excellent. For nuclear, take a look at project Dumbo. NERVA was never designed to get 1g+ acceleration. For chemical, I'd start with an oxygen breathing first stage and possibly 2nd stage, as high and mostly fast as possible. These could be horizontal take off and landing, ie. airplanes and the final orbital stage a rocket. My reasoning? Calculate the proportion of fuel weight that is oxidizer. Even if it is only practical to reach Mach 1 and 30,000 feet, you have some velocity and are now above most of the atmosphere. If they get the SCRAMjet working, it should be possible for an air breathing 2nd stage to reach mach 7 or so.

Hm. Have some similarites with MG-19 concept.

The NTR that was finalized during the NERVA program was actually certified as flight capable when the program was grounded, and several more powerful (and I mean REALLY much more powerful) NTR's had been hot fired out in Nevada (Phoebus II had a core about the size of a minivan but produced something on the order of 4,000 MW of thermal energy. NTR's were also designed with T/W ratios of up to 7:1.

Timberwind, a 1990's era design was also designed with a T/W ratio of greater than 1:1.

So if anyone is interested in restarting the program, there is a lot of development work already done and validated,

Dilandu wrote:Well, as we say in Russia - "do you need a proper taxi, or you really need a ride to some place?" There are a lot of nuclear powered satellites launched in orbit in 1980; some of them crashed, but the results wasn't cataclysmic at all.

There´s a difference by several magnitudes of risks.

And IIRC, there was at least one satellite that DID cause bad stuff when it came back down, because it failed to burn up properly on reentry.

A big chunk of rocket isn´t going to burn up on re-entry to the point where dangerous materials are effectively gone.

aairfccha wrote:
Reaction Engines Ltd disagrees, they at least plan on Skylon flying to space in the 2020s.

No they do not disagree, as Skylon is set to deliver merely 15t to orbit, compared to the space shuttle´s almost 25t. So it´s actually a step backwards.

So, great for putting up SMALL and MEDIUM sized stuff, but utterly useless as a heavy or superheavy lifter.
Which is needed to justify that "space-going 747" comparison. Sure, being able to put up lots of small stuff for drastically less cash will be great. Except that it will make it even less interesting to invest in heavy lift capacity.

And frankly, i´ll believe it is working when i see it functional. Not before then. In case you missed it, there has been several projects like Skylon before, none have become operational. First one was suggested in the 1940s.

Just having it reliably reach mach 5 is not going to be an easy task. As you will notice if you read about the SR-71 or the MiG-25.

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

The problem with both above isn´t to reach that point, several crafts have done that, but to do it while carrying a heavy payload reliably.

Noone has managed that and it doesn´t look like anyone will do it anytime soon.
It´s no big deal being able to get an X-15 into space or the X-37 into orbit, but the first can´t carry any payload and the second is only a light lifter.

Joat42 wrote:That's not entirely true. The NERVA program for example was a success, the latest iterations of the engine worked reliable and NASA was in the process of designing a vehicle around it when the political backing for it disappeared due to various reasons.

If the development of NERVA had continued we probably would have a quite large permanent presence on the moon today among other things.

The NERVA program was for an IN space engine, not a lifter. It REQUIRED the nuclearpowered version of the Saturn rocket to get into space. Because even the regular Saturn V didn´t have enough lift.

Not to forget how they had several explosions and one emergency nuclear core dump during the program.

And simple fact, it was called successful as much to get the project to keep running as anything else. Behind the scenes talks with the people doing the science, later shows that the program timeline was in reality wildly overoptimistic, and the scientists could not actually give a simple yes or no on whether it was going to work as intended in the end.

Tenshinai wrote:

Joat42 wrote:That's not entirely true. The NERVA program for example was a success, the latest iterations of the engine worked reliable and NASA was in the process of designing a vehicle around it when the political backing for it disappeared due to various reasons.

If the development of NERVA had continued we probably would have a quite large permanent presence on the moon today among other things.

The NERVA program was for an IN space engine, not a lifter. It REQUIRED the nuclearpowered version of the Saturn rocket to get into space. Because even the regular Saturn V didn´t have enough lift.

Not to forget how they had several explosions and one emergency nuclear core dump during the program.

And simple fact, it was called successful as much to get the project to keep running as anything else. Behind the scenes talks with the people doing the science, later shows that the program timeline was in reality wildly overoptimistic, and the scientists could not actually give a simple yes or no on whether it was going to work as intended in the end.

The problem has never been getting into orbit, the problem has always been that after you have gotten there you don't have the energy-budget to go anywhere else other than down again. NERVA was to solve this problem and be used for orbit boost and beyond.

According to what I have read, there were no need for a completely nuclear powered Saturn rocket to get NERVA into orbit; just the traditional first and second stage engines.

And the accidents where minor, a hydrogen explosion and the core dump was because someone didn't keep tabs on the liquid hydrogen storage level so the engine ran dry; the engine itself never had any problems.

Joat42 wrote:The problem has never been getting into orbit, the problem has always been that after you have gotten there you don't have the energy-budget to go anywhere else other than down again. NERVA was to solve this problem and be used for orbit boost and beyond.

Seriously incorrect. Getting anything heavy into orbit is a BIG problem.
Small stuff isn´t so hard, but it´s also useless for going anywhere further.

Joat42 wrote:And the accidents where minor, a hydrogen explosion and the core dump was because someone didn't keep tabs on the liquid hydrogen storage level so the engine ran dry; the engine itself never had any problems.

Eh, those two are the two "worst" incidents, there were more. Several of which could have become VERY bad. At least 2 WOULD have gone really bad if the engine had been part of a real rocket.

So no, i understand quite well why the project was dropped once it lost political backing.
It had potential yes, but it was far from a ready and useful technology.
And it added dangers to technology that is already inherently very dangerous.
Not the greatest of combinations.

Tenshinai wrote:

aairfccha wrote:
Reaction Engines Ltd disagrees, they at least plan on Skylon flying to space in the 2020s.

No they do not disagree, as Skylon is set to deliver merely 15t to orbit, compared to the space shuttle´s almost 25t. So it´s actually a step backwards.

...snip...

Really, a step backwards. What currently is the worlds lift to orbit capacity?

Seeing as how the space shuttle exists in museums now. And it was a huge step backwards from the previous capability.

Kind like the US's manned space program doesn't exist.

OR all the flack the Indian government got for that robotic mission. Seems like all that money would have been better spent on social justice programs. <shrug> Fun, for sick values of fun, to watch other countries making the same mistakes that the US made.

T2M

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 ...

Edit ... Edit ... Edit ... Auuughhhh! I hate getting old. I stand corrected and thank you. It was Alan Shepard. Dumm, de dumm. Dumm de dumm. I'm loosing my mind ... I can feel it ... I can feel it. Daisy, daisy ... blah blah blab.


... 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.