Next-Generation launch technologies achievable with CURRENT technology

[Bill Phil]

A bit off-topic:

A cradle is where a baby goes after being born and all that. Calling Earth the cradle is not the same as calling it the birthplace.

Drag losses are generally about 1% of the Dv to get orbit.

9000 to 100.

[Robotengineer]

A bit off-topic:

A cradle is where a baby goes after being born and all that. Calling Earth the cradle is not the same as calling it the birthplace.

Drag losses are generally about 1% of the Dv to get orbit.

9000 to 100.

We don't know that Earth is the birthplace.

[SargeRho]

We do actually know that.

[Rakaydos]

Second, I wanted to ask about Electrodynamic Tethers. Supposedly, these are devices that can push off Earth's magnetic field using an electric current running through a rotating wire to generate force (the Earth acts as the reaction mass- but is moved very little due to its enormous size). Are these credible? Has anyone else here ever heard of them before?

If they're real, I'd imagine maybe there would even be a way to exploit this on a smaller scale inside of a spacecraft to construct a vehicle that accelerated orbit purely by pushing off the Earth's magnetic field... It's not magic propulsion- there is still reaction mass (the planet itself), it's just not contained inside the spacecraft. Is there something I'm missing here. or would this actually be possible? I'd assume Microwave Beamed Power could be utilized to provide a sufficiently lightweight/dense power source to run such a propulsion system...

Regards,

Northstar

I'v seen that before, and it was suggested as one of the options for the Comunity Cubesat payload.

Personally, I feel that earth orbit is not electrotether's true calling. The real answer is outside the Jupiter-Io trailing lagrange point (L4, I believe)

Place the satelite inside Io's gravitational sphere of influence. the satelite wants to fall toward Io, and Io (ever so minutely) wants to fall back to the satelite.

But Io has no magnetic field, so the satelite is still withing Jupiter's MAGNETIC sphere of influence. With an electrotether, the satelite can drain it's orbital velocity into "free" electricity, until it deorbits itself.

-But if you BALANCE these effects...-

you are slowly draining -IO's- orbital velocity into electricity by gravity trator. Free electricity that will last for millions of years of continious use, in the outer solar system and local to the Jovian moon system...

[tater]

The best "technology" would be to not have Congress decide what NASA has to buy. We'd not have multi-billion dollar stuff like Orion (less capable than Dragon 2), and we'd not have congress quashing orbital refueling every time it pokes its head up.

[Northstar1989]

Well, even IF miniaturization allows for all current satellite types to be launched by a laser launch system (an impossibility btw.) it would eat up what? 30 launches a year? For a complex designed to launch thousands of satellites / payloads a year.

Where do you ever get the idea of a LASER launch system??? I never said lasers, I said *microwaves*. There's a BIG difference, because high-powered microwave beams are MUCH cheaper and more cost-effective... (they also suffer far less atmospheric absorption)

There's also no need for miniaturization. Of the satellites, anyways. What I'm talking about is a launch system that can EASILY launch current-sized satellites. If FACT, Microwave Beamed Power systems work BETTER the more you scale them up, because a larger rocket has a larger thermal receiver as a target for the microwaves, and thus you don't have to focus the beam quite as well... You would have no issues launching humans with this system- in fact in many ways it could be safer to sit atop a Microwave Thermal Rocket than a chemical one, as there might only be a single fuel type and no oxidizer aboard (LOX *can* be used for an afterburning-effect if desired, to greatly increase thrust at the expense of a sizable hit to ISP, however...) and far fewer parts likely to fail...

That system would be an even bigger waste than the ares or SLS, could possibly be, especially considering that you would still have to have an assortment of other rockets, for payloads too big for the laser launch system.

No, you wouldn't have an assortment of chemical rockets. If microwave beamed power were implemented on a sufficient scale, you wouldn't have need for them anymore...

Rockets are fine for now imho. and they will be fine enough for initial expansion into space, if mass produced on a scale necessary for expansion into space.

Microwave Thermal Rockets are still rockets. In fact, it's right in the name. I think you have a DRASTIC mis-understanding of how Microwave Thermal Rocketry actually works. Here is are two media articles I suggest you read to enlighten yourself:

http://www.cnet.com/news/rocket-scientist-aims-to-relaunch-propulsion-technology/

http://nextbigfuture.com/2014/02/escape-dynamics-and-microwave-power.html

And if you want more detail and scientific/engineering explanation, read this scientific paper from the Caltech library:

http://authors.library.caltech.edu/3304/1/PARaipcp04b.pdf

- - - Updated - - -

Drag losses are generally about 1% of the Dv to get orbit.

9000 to 100.

The standard, often-cited figure is 10 km/s to LEO. 9 km/s is spent fighting gravity and gaining horizontal velocity+altitude, and 1 km/s is lost to atmospheric drag.

Don't know why you brought that up though. And the figure varies GREATLY according to rocket size (larger rockets experience proportionately less drag due to the Square-Cube Law), TWR (slow ascenders experience less atmospheric drag), shape, and ascent profile. Not to mention spaceplanes- which would be one of the single best uses of Microwave Thermal Rocketry (because you could use the atmosphere for propellant in the beginning via Thermal Turbojets, and get off the ground and all the way to orbit with a TWR significantly less than 1) experience significantly more atmospheric drag than rockets... (but lose less Delta-V to gravity)

Regards,

Northstar

[Nibb31]

None of those things are "CURRENT" technology AFAIK.

[Kryten]

You might find this interesting;

http://www.thespacereview.com/article/1534/1

[Northstar1989]

You might find this interesting;

http://www.thespacereview.com/article/1534/1

That author's a bit of a prick- broadly dismissing all technological progress (VASIMR, for example, which we now have a WORKING prototype of on the ISS, he states would take "decades and billions of dollars"- which laughably, I assume he actually thinks is a lot of time/money in space-exploration terms...) and mocking those who support such ideas.

He's right people get a little carried away with things like Commercial-only Space and NASA-reorganization (and because I understand the relevant issues, I've never been a huge fan of either...) But he's WAY off-base when it comes to technology, and doesn't actually make any legitimate arguments to prove his point rather than a bit of hearsay about what *he* thinks the real engineers are struggling with in regards to a Mars sample-return mission...

The ideas proposed in this thread are a very specific set of technologies to solve a very specific problem. Namely, the high launch-cost of getting anything to Low Earth Orbit (the first step to ANY other mission.)

Now, don't get me wrong- I never said there aren't PLENTY of other technological and engineering challenges to space exploration and utilization. But the main reason we haven't solved them is due to lack of government financial support to do so... If launch costs were lower, total mission costs would take a sharp hit as well (not only do launch costs make up a significant portion of mission costs- high launch costs also force enormous increases to design costs for things such as scientific instrumentation, as the necessary tools/components have to be built to be VERY lightweight...)

Now, back to the topic of this thread. What do *YOU* think are valid technological approaches to reducing launch costs?

(I'll be the first to admit- there are a lot of non-technological solutions as well that are simply based on changing HOW you think about launch vehicles or manage space agencies- the Big Dumb Booster approach, or the Aquarius low-realiability approach for launching fuel and consumables, for instance. But discussing those as well is beyond the scope of this thread- which is intended as a focused discussion specifically on technological solutions that don't require major scientific breakthroughs...)

Regards,

Northstar

P.S. Some posters have criticized the solutions here as being futuristic rather than possible with current technology because they don't understand an important distinction: that between precision/finesse of execution and political barriers, and solutions requiring technological breakthroughs...

A "skyhook" doesn't require us to invent new materials or make breakthroughs in nuclear physics, for instance, but it DOES require *incredible* precision in suborbital rendezvous (between the lower end of the tether and the suborbital spacecraft), and as such may not actually ever be realized. Microwave Beamed Power doesn't require *any* scientific breakthroughs (we already have developed the necessary microwave-transmitters for industrial/metallurgical uses, for instance), but it DOES require political approval to shoot hundreds or thousands of Megawatts of long-wavelength microwaves through the air (which due to their wavelength, WON'T actually pose a significant health threat to human beings nearby- although they could fry the semiconductors on passenger airplanes crossing their path, as silicon chips *are* significantly absorbant to these wavelengths, unlike organic matter...) at an ascending rocket or spaceplane- and thus may never see realization due to overblown public fears of radiation (this is *exactly* the same as fear of cellphones causing cancer, actually- the relevant wavelengths are far too long to ionize your DNA...)

There is a difference between what is POSSIBLE with today's technology, and that which government officials (who don't even all understand how the Internet works) will actually fund...

Edited January 10, 2015 by Northstar1989

[Bill Phil]

Why not reduce the cost of the rocket itself? Standardized turbo pumps. And then the engines would be designed based off of the turbopump's properties.

Turbopumps are generally the most expensive part, and that's counting development. But a standardized system would mean that if you build a new rocket engine, the turbopump is already developed.

[shynung]

Most of a typical launch vehicle rocket engine is the turbopump itself. The rest are simple things like pipes, valves, combustion chambers, and the throat-nozzle assemblies. These are relatively simpler than the turbopump itself, as these rarely haves significant moving parts.

So yeah, standardizing turbopumps and mass production would be a good way to go, but sacrificing flexibility in the process. A single pump design has a rated power and mass flow which can't be tweaked too far from the original specs without rebuilding it entirely. For larger engines, this can be gotten around by using multiple pumps, but the smaller engines would have to carry oversized pumps, which eats into payload mass.

[Bill Phil]

Not ONE pump... But many pumps. Similar to what NACA had done with airfoils.

[shynung]

Pumps and engines in general can't be scaled up or down as easily as airfoils or pipes without altering their performance characteristics. In particular, if a single turbopump engine was simply doubled in size, the thrust may be increased due to more mass flow, but the larger turbine has a larger rotational inertia, which will make it respond slower to changes in power input compared to its smaller counterpart. To reduce this rotational inertia, one would make the turbines out of lighter materials, which may have a lower critical working temperature, which would have necessitated a lower combustion temperature, which means a lower ox-fuel ratio, which means redesigning the combustion chamber, etc. etc. It's complicated as hell.

An ideal configuration would be doing what SpaceX is already doing: make a single design (in this case, the engine), and modify it to work at different conditions (i.e. SL atm pressure/vacuum), but retain the original design as much as possible, so that the same manufacturing tools and techniques can be made to produce both variants. The Merlin engines used by the Falcon 9 has almost identical engines at both stages, the main difference being that the upper stage engine has a nozzle extension for vacuum operations.

[Bill Phil]

I don't think you understand...

Let me oversimplify:

If you wanted to design an engine similar to an RL-10, you would:

1st: Determine thrust range and propellant type

2nd: Determine mass flow based on estimated exhaust velocity and thrust requirements

3rd: Select a turbopump from a "catalog" that is closest to the mass flow (always round up) and is designed for the propellants being used

4th: Design the rest of the engine around that turbopump set's specs (mass, size, mass flow, fluid, etc.)

The point is that there would be a bunch of Turbopumps. Defined by their size, mass flow, and other specifications. This way you don't need to develop the TP, and it makes it much cheaper to develop and build engines. However, new engines wouldn't be very common, like you say, which would make the whole launch vehicle easier to handle, in terms of money.

[shynung]

I see. The turbine makers would try to expand the market by offering several turbopump designs, which are not tied to any specific engine. The engine makers would then assemble the rest of the engine around that one pump they chose for the job.

Though, I was thinking something else before. I thought that there would be only very few turbopump designs but plenty of complete engines, most of which were sharing a turbopump type. It's something that a single engine company who makes their own turbopumps seemed reasonable to do, like automobile companies using the same engine in different models.

Think of it like this: an engine company offers three engine designs, each named Medium, Large, and Super Large. They all use a common turbopump, but differs in how much pumps are used in each design; Medium uses one, Large two, Super Large four. That way, the company can offer engines with differing performances while saving on TP development.

Edited January 10, 2015 by shynung

[Bill Phil]

That would be pretty complicated, however. At that point it would be smarter to just do what SpaceX has done, using variants on a common engine base. Same number of TPs, but you save on development of the bigger engines because you just cluster the smaller ones. Although, there are many things that can be done in the engine field of rocketry...

[shynung]

Not much development can be done with liquid rocket engines, other than materials and manufacturing advances. The technology itself is already mature by the 70's, and not much progress in terms of design changes has took place since then. Any further advances would have to be gotten from using more energetic propellants or nuclear thermal rockets.

And by energetic propellants I mean things like chlorine trifluoride, or the like. Super-reactive stuff, basically.

[Bill Phil]

There are still developments to be had. Just not in the technology itself. Manufacturing techniques, mass production, and many other things that aren't directly related to the field, but could improve it indirectly.

[Northstar1989]

Hey guys- you've heard of Full Flow Stage Combustion, right? You know, the cycle that will be utilized on the new Space-X Raptor Meth/LOX engines? THAT is a major advance in engine design (although to be fair, FFSC has been used several times before in engines that never made it off the test stand as funding was pulled on their intended launch vehicles...)

Still, the biggest advance in rocketry will be when we stop carrying all the energy necessary for the mission onboard the rocket. I.e. through Microwave Beamed Power... (which is also nice because you can use the same system for deep-space propulsion by high-powered ion engines relying on beamed power..)

Regards,

Northstar

[shynung]

you've heard of Full Flow Stage Combustion, right?

Yeah, that was used in the SSME/RS-25 engines.

[78stonewobble]

There are still developments to be had. Just not in the technology itself. Manufacturing techniques, mass production, and many other things that aren't directly related to the field, but could improve it indirectly.

True... I personally think people tend to underestimate the chemical rocket. I do believe that we can marginally improve ie. a saturn 5 design for use today through possibly lighter materials, lighter welds, possibly simplifying certain parts due to us being able to make them better and certainly lighter electronics and automation. Tho it might be slight improvements overall.

But yes, mass production. We have never had a large og multiple large factories, just dedicated to spitting out rockets... (apart from possibly ICBM's). The global car industry has a revenue of what... like 600 billion dollars a year? Nasa, at the most had 43,5 billion. In one year... of which only some directly went to production.

I still say, that the way to go, is to spend money, til we have scheduled regular heavy launches, atleast 5+ a year, for 20-50 years.

[shynung]

True... I personally think people tend to underestimate the chemical rocket. I do believe that we can marginally improve ie. a saturn 5 design for use today through possibly lighter materials, lighter welds, possibly simplifying certain parts due to us being able to make them better and certainly lighter electronics and automation. Tho it might be slight improvements overall.

But yes, mass production. We have never had a large og multiple large factories, just dedicated to spitting out rockets... (apart from possibly ICBM's). The global car industry has a revenue of what... like 600 billion dollars a year? Nasa, at the most had 43,5 billion. In one year... of which only some directly went to production.

I still say, that the way to go, is to spend money, til we have scheduled regular heavy launches, atleast 5+ a year, for 20-50 years.

That's about it. Though, regular people never really underestimate chemical rockets, even solid ones. They're mighty beasts, to say the least.

I think SpaceX is going the right way. Their Falcon 9 rocket uses almost identical engines in both the lower and upper stages, so that all of the engines can be made in the same factory. Even more, a single rocket uses 10 engines (9 on the lower stage, 1 modified on the upper), so they reap the benefits of mass-production even with low launch rates.

[78stonewobble]

That's about it. Though, regular people never really underestimate chemical rockets, even solid ones. They're mighty beasts, to say the least.

I think SpaceX is going the right way. Their Falcon 9 rocket uses almost identical engines in both the lower and upper stages, so that all of the engines can be made in the same factory. Even more, a single rocket uses 10 engines (9 on the lower stage, 1 modified on the upper), so they reap the benefits of mass-production even with low launch rates.

While I do hope SpaceX will have success, I don't think they will be or can be a revolution of the launch industry.

The spaceshuttle showed us that reuseability isn't necessarily a blessing and can actually be a hindrance to the mass launchings necessary to brings costs down and you do need relatively high launch rates to reap real benefits of mass production.

PS: Hmm for fun, I just tried calculating how much it would have cost to launch all the shuttle programmes payloads on Saturn V's... 25,7 billion $ vs. the total spaceshuttle programme cost of 209 billion $. Can that be right, 12 percent of the shuttle costs?

EDIT: I don't think the saturn V numbers include research and development, which would probably raise the Saturn V numbers quite a bit... Still my guestimate would be that the Saturn V could have put the same payload in orbit as the shuttle, but at probably half the price or under.

Edited January 16, 2015 by 78stonewobble

[Rakaydos]

The shuttle was "reusable" in the same way a politician is "honest." The SRBs only reused scrap metal, at cost, just to maintain the claim that the "entire rocket is reusable." Like the so called "Senate Launch System" that is supposed to replace it, the shuttle was designed to fill political objectives, not scientific ones- And jobs refurbishing the shuttle were more politically valuable than not needing refurbishment in the first place, like if they'd stuck to the titanium heat shield instead of the foam glass tiles.

SpaceX, on the other hand, is a corporation, not a goverment. Far from trying to create taxpaying jobs, a corporation is biased toward providing the most marketable service/product for the least overhead, and keeping all the money for itself. This means SpaceX has far more reason to have EFFECTIVE reusability than the US goverment ever did. The Falcon and the Space Shuttle simply arnt comparable in that regard.

[78stonewobble]

The shuttle was "reusable" in the same way a politician is "honest." The SRBs only reused scrap metal, at cost, just to maintain the claim that the "entire rocket is reusable." Like the so called "Senate Launch System" that is supposed to replace it, the shuttle was designed to fill political objectives, not scientific ones- And jobs refurbishing the shuttle were more politically valuable than not needing refurbishment in the first place, like if they'd stuck to the titanium heat shield instead of the foam glass tiles.

SpaceX, on the other hand, is a corporation, not a goverment. Far from trying to create taxpaying jobs, a corporation is biased toward providing the most marketable service/product for the least overhead, and keeping all the money for itself. This means SpaceX has far more reason to have EFFECTIVE reusability than the US goverment ever did. The Falcon and the Space Shuttle simply arnt comparable in that regard.

There is no inherent reason that a government project should be more expensive than a private enterprise. All things being equal it should to could be less expensive considering it doesn't have to turn a profit. That a government project is usually more expensive is due to, as you mention, shortsighted local political "appeasement", inefficient management including salary negotiation and what not, but I digress... This is off topic.