Nyrath

http://blog.wired.com/wiredscience/2009/01/bright-flash.html

What could it be?

A Bezerker destroying a civilization?

An alien starship invasion force using breaking thrusters to enter our solar system?

A Stargate opening?

A dimensional rift allowing Cthulhu to enter our space-time continuum?

Re: Space drives.

Now, you have two distances: [a] the distance between the planet and its sun, and the distance between the jump point and its sun.

The "superior" object is the one farthest from its sun. The "inferior" object is the one closest to its sun.

The question is: how far is it from the planet to the jump point? This will of course vary as the planet moves in its orbit.

The planet and the jump point are at their closest when both are on the same side of the sun. The distance between is equal to SuperiorDistance minus InferiorDistance.

The planet and the jump point are at their farthest when they are on opposite sides of the sun, with the sun inbetween. The distance between is equal to SuperiorDistance plus InferiorDistance. (actually a bit more, since you have to zig-zag around the sun).

The average distance between is the average of these two distances. As it turns out, the average distance is equal to SuperiorDistance.

Re: Medals for Robots

This also happened with NASA’s Phoenix Mars Lander.

http://www.thespacereview.com/article/1270/1

Re: Medals for Robots

Many of Keith Laumer's BOLO stories are about how the robotic Bolos are far more noble and valiant than the pig-headed human generals and the slimy human politicians.

Re: Slow Space Elevator

*sigh*

Tangential point: I had no idea this discussion had anything to do with building RPGs or science fiction.

Well, you might have been tipped off by the fact this is a thread in a forum about the HERO games RPG, in the section about their science fiction game.

You apparently did not bother to read the index page for my website. You complain about its authoritative tone and its emphasis on science to the exclusion of political motivations and other soft factors.

If you had perused the index, you may have noticed that the context was presenting the scientific equations which define the outer parameters of what is theoretically possible given the laws of physics. This was intended for science fiction authors and game designers who want a little more accuracy in their works.

Soft factors like political motivations are up to the author, they are out of the scope of my site. If the author wants scientific accuracy, the soft factors can constrain the solution more narrowly than what is allowed by the laws of physics.

Moving outside the laws of physics removes the scientific accuracy, but such non-hard-science authors wouldn't be reading my web site in the first place.

As I stated above, such scientific inaccuracy is perfectly permissible in an RPG. Most game masters have better things to do than calculate the delta vee of their spacecraft.

You also complain about "absence of actual refutation of a plausible theories via experimentation". Yes, this is a concern, but paradigm breaking surprises in the fundamentals of physics have grown scarce enough so this is not a major concern. e.g., physics predicted that the 1959 Russian Luna-1 probe would go sailing past the moon. There was a chance that it would splatter on one of Eudoxus' crystal celestial spheres, but as I mentioned earlier, that's not the way to bet.

And again, if there was such a paradigm breaking surprise, there is a 50% chance that it would make things worse for your desired outcome, instead of better.

Yes, "soft" science fiction is more concerned with speculation than scientific accuracy. My website is for hard science fiction. If you do not prefer hard science fiction, you would do well to avoid my site, and the others like it. But I take exception to any attempt to outlaw hard science fiction.

As to why we were talking about hard science fiction in the first place, if you will take a peek at the start of this thread, it was about the scientific feasibility of a space elevator. Which means you should have avoided this entire thread in the first place.

Re: Slow Space Elevator

Well, :shrug right back atcha

The site I linked to is my own, obviously, but if you read much of it you will discover that it is mostly composed of quotes from scientists who actually know what they are talking about (unlike me).

The motive being that to make scientifically accurate RPGs/computer-games/SF-novels/whatever, you have to use accurate science.

If you do not, then there is nothing stopping you from having your space fighters being propelled by rainbow-colored unicorns in the engine room (providing thrust via prismatic flatulence), attacking Marvin the Martian's space scow with your dreaded atomic-powered spitwad shooter.

If there are no rules, then you have to live the consequences of no rules.

I've noted about three fallacies in your rebuttal of space fighters, but since this is already covered in detail in my site, I'll leave it at that.

Re: Slow Space Elevator

While this makes sound points in terms of our current technical capabilities and foreseeable political realities' date=' the position is also dependent upon certain underlying technological and tactical assumptions that may not hold true with major leaps in scientific understanding, technological ability, and colonization.[/quote']

 

Yes, that's the standard "but maybe a scientific break-through!" thesis. I talk about it here:

http://www.projectrho.com/rocket/rocket3al.html

 

My take on it is that thesis is very much like an inside-straight in poker: yes, it is possible, but that's not the way to bet.

 

More specifically: if science has advanced to the point where spacecraft do not use rockets for propulsion, it is going to have advanced in other areas to the point where the world will be totally unrecognizable to the players. We are talking about a world where transhuman and post-human people live forever in cyberspace as patterns of digital data as they use nanotechology to disassemble the solar system in order to build a Dyson sphere, while battling alien Matrioshka brains armed with zero-point energy weapons.

 

It ain't gonna be Battlestar Galactica.

 

Now, here comes the Important Disclaimer:

I find space fighters, SSTO ships, and all the other beloved items to be totally acceptable in a Star Heros game. You want it, your players want it, everybody is doing it.

 

The only time I disagree is when somebody crosses the line into the real world, stating that this is actually going to happen in our future.

Re: Slow Space Elevator

Because most ideas do.

And it's more likely to fail than reusable lifting solutions (SSTO, MSTO, whatever) because there's more to it that's unproven and more that's hypothetical. We've built a reusable MSTO, and it was pretty good for a first try. The two catastrophic failures were caused by human error (in the system at NASA, etc, not crew), and not by inherent flaws in the concept.

You are using the term "fail" in a manner I am not expecting.

Before the Wright Brothers flew their heavier-than-air aircraft at Kitty Hawk, there were dozens of airplanes prototypes that failed.

But the concept of heavier-than-air flight did not fail. The fault was in execution of the concept, not the concept itself.

And in any event, the experimenters were not deterred by the hordes of nay-sayers who yelled that heavier-than-air flight was impossible. The point was: the nay-sayers had not done the math.

In the same way, one should not be deterred from developing a space elevator. One makes prototypes and does experiments to get more data, and to discover problems with the concept. One does not just say "oh, it's a new concept so it will probably fail" and give up. Instead, you get hard data, crunch the numbers, and base your assessment on that.

Using your logic, the designers should not have even started on SSTO vehicles either.

I also would suspect that you are one of those who mistakenly think that space fighters are a good idea. It fits the pattern of distaste for space elevators.

Re: Is there a Janes Ships of the Terran Empire?

Have you looked at Future Armada?

In the gallery section is a 3-D star map on a hex grid, that is reasonably accurate.

It does use equatorial coordinates instead of galactic, but most gamers could care less.

Re: Slow Space Elevator

Why expect the tether to work as is hoped? Why expect the concept to work as hoped?

 

Ideas fail all the time, and it strikes me as foolish to condemn all research into reusable lifting vehicles to the dustbin on the hope that you can fling a string into space and then run something up it.

Why expect the tether to fail? Why expect the concept to fail?

And if a company starts developing a space elevator, do you really think that a law will be passed making it illegal to develop SSTO? For that matter, if people are now working on SSTO, why should it be illegal to work on a space elevator?

These matters will be decided by market forces. If a viable design for a space elevator is not forthcoming, the venture capitalist who bankrolled development will be out some cash.

But if a viable design appears and manages to be implemented, those clients with huge payloads they want to get into orbit will naturally take their business to the less expensive option. Then as I said before, the space elevator will become the orbital version of the trucking and rail road train transport company, and the SSTO will become overnight air freight.

Re: Slow Space Elevator

Sure. But there's no reason it HAS to. If you use a cold-gas thruster for initial impetus' date=' then provided the Rocket doesn't physically impact the zeppelin, there's no reason for the launch procedure to damage the transport in any way.[/quote']

What about using a system like this?

 

http://www.defenseindustrydaily.com/airlaunch-llc-performs-quickreach-test-01308/

 

http://www.airlaunchllc.com/News.htm

(scroll down to pictures at "DARPA, AIR FORCE AND AIRLAUNCH LLC DROP TEST SETS NEW C-17 RECORD")

Re: Well, they had to name it something...

If the capacity to do non-computer-based calculation isn't dead yet' date=' it's definitely on life support. [/quote']

Oh, it is everywhere. On the introduction page to my Atomic Rocket site, I did get irate enough to post a snarky comment to the effect that if all the equations confuse the reader, they can look at the pretty pictures.

 

On the other hand, have you ever read Isaac Asimov's short story "The Feeling of Power" ?

 

The Google calculator has the advantage that is already knows all the conversion constants, so you don't have to look them up.

Re: Well, they had to name it something...

If I've done the cross-ID right, it's about 150 pc away, and this could be called the Muscae 1 dark cloud. The cloud is probably 6 or 7 parsecs long.

Could someone please translate that into light-years for this scientific layman?

489 light years away.

From 19.6 to 22.8 light years long.

Here's what you do:

Go to Google. Type in "6 parsecs in light years" and hit return. Google will return the answer. Google can do this with all sorts of different measures.

Re: Slow Space Elevator

Also' date=' I'm unsure why people get stuck on the idea of SINGLE stage to orbit. Yeah, it sounds cool and science-fictiony, but what other benefits does it have over, say, an air-breathing first stage to carry the orbiter to the upper atmosphere?[/quote']

Or any other multi-stage rocket with recoverable stages.

No, one gets the distinct impression that people get stuck on the idea of SSTO because Tom Corbett Space Cadet did not ride a disintegrating totem pole into space.

Re: Slow Space Elevator

How long does it take to assemble' date=' fuel, and preflight the Space Shuttle for launch?[/quote']

Space Shuttle Columbia was once launched twice within 56 days, but that was the shortest turnaround time of any shuttle.

Re: Slow Space Elevator

Depends on what I'm shipping. I'm not going to ship an organ for transplant by UPS Ground.

 

Similarly, there are going to be things for which you can't wait around for a few weeks while the spacevator trundles its way up a handwavium thread.

Yes, as per my analogy, you'll use emergency overnight air express for that.

For everything else you send it by rail.

Re: Slow Space Elevator

And there's no question about the superiority of the energetics of a space elevator. It's just that the economics doesn't reduce to the energetics. You have to build the darn thing. And' date=' apparently, support the nontrivial costs of long transit times.[/quote']

Agreed. It seems to me the controversy is over short-term vs. long-term benefit.

 

SSTO can probably be made viable more quickly (i.e., short-term). It is just that it's a dead end. There is no way that one can make huge space stations, lunar colonies, and large space fleets by boosting a few tons into orbit every month or so.

 

The analogy is that most cargo in the US is shipped by train or by truck. Not by airplane. Like rockets, cargo aircraft have to be fragile and lightweight, gulp down huge amounts of fuel, have comparatively limited cargo capacity, and if they turn off their engines they fall to the ground.

 

Trucks and trains needed to have the huge infrastructure of roads and train tracks built first. And they are not as quick as air freight. But they were far cheaper in terms of fuel expended, have huge cargo capacity, and the prime movers do not need all the fragile and high tech engineering that a plane requires.

 

Take your pick.

Re: Slow Space Elevator

Going back to previous discussions on the matter of the beanstalk' date=' the absolute disdain some people expressed for even the hint of SSTO in the discussion was a little stunning.[/quote']

It is simple math.

 

The difference in potential energy between an object on Earth and an object in GEO is a mere 15 kilowatts per kilogram. The Space Shuttle takes gigawatts per kilogram to put an object in LEO, it cannot even reach GEO.

 

Chemical rockets like the proposed SSTO are getting pretty close to the theoretical maximum. To get better performance out of a rocket, you need more energetic fuel. Unfortunately this means nuclear. And that means zillions of environmentalists on your lawn waving torches and pitchforks.

 

You have to make a chemical rocket out of gossamer and cobwebs in order to make it a single-stage-to-orbit. All of our current heavy lift vehicles are multi-stage-to-orbit because of this. The DC-X SSTO prototype cracked its fiberglass skin with a hard landing on test flight #8

 

Nuclear is no prize either. A solid core nuclear thermal rocket isn't that much better than chemical. To get the sort of performance to boost huge payloads into orbit, you need something like an open-cycle gas core nuclear enegine. Or Project Orion.

 

Orion involves setting off about one thousand nuclear bombs at regular intervals to boots into orbit. Just think about the fallout. Open-cycle gas core is even worse. It is the equivalent of vaporizing the entire reactor and blowing it out the exhaust nozzle. The environmentalists will have a conniption fit.

 

Space elevators, on the other hand, have a much better theoretical maximum performance. The early models will be only slightly better than rockets, but it has much more potential for improvement.

 

Another advantage is that a rocket cannot "rest." If it wants to stop for some reason at 100 kilometers, it has to burn propellant just to keep from falling back to Earth. Payload on the space elevator, on the other hand, can be stopped indefinitely (except for all the payload canisters behind it).

 

This is why we have such disdain for SSTO.

 

Here's an analogy:

 

What if the Battleship New Jersey in the US Navy was constructed by assembling it in Nevada, and equipping it with huge caterpillar tractor treads so it could travel over the desert to the Pacific Ocean.

 

Pretty silly, isn't it. Much better to ship all the girders and materials by train to the ocean-side dock and assemble it there. The battleship will not be capable of traveling to Nevada, but that's what trains are for.

 

In the same way, it makes no sense to build a huge space-going battleship on Earth, then having it lift into orbit. It makes far more sense to transport the girders and stuff into orbit by a space elevator and assemble the battleship in orbit. The battleship cannot go to Earth but why would it want to?

Re: Slow Space Elevator

The kind of materials that would make the spacevator possible would reduce the amount of weight taken by the structure of an SSTO drastically' date='[/quote']

Not necessarily. A space elevator needs materials that make strong tension members, a SSTO needs materials that make strong compression members. A material that is good under tension is generally pretty poor under compression, and vice versa.

Re: Slow Space Elevator

I see this project being a tough sell for the public.

Agreed.

And you didn't even mention the ever-popular "why should we spend money on outer space when there are so many problems we could spend money on right here in our own country?"

My personal take on that last bit is those problems tend to be infinite money-sinks that can easily absorb all of a given country's money but with no visible effect.

Re: Solar HERO: Two from Saturn's moons

IMO it's looking more and more likely that the moon systems of Jupiter and Saturn may have conditions to form life of an entirely different chemical makeup from any we presently know

As you probably already know, there are a few candidates for other biochemistries here:

http://www.projectrho.com/rocket/rocket3aa.html#classification

scroll up to In a science essay "Not As We Know It"

Re: Slow Space Elevator

But how much damage will the remaining 1% do?

from http://en.wikipedia.org/wiki/Space_elevator_safety#In_the_event_of_failure

...in most cable designs, the upper portion of any cable that fell to Earth would burn up in the atmosphere. Additionally, because proposed initial cables have very low mass (roughly 1 kg per kilometer) and are flat, the bottom portion would likely settle to Earth with less force than a sheet of paper due to air resistance on the way down.

Re: Slow Space Elevator

And how would it affect the cost? It's supposed to be a cheap way of getting to space, but so was the space shuttle, which didn't live up to that promise.

 

Edit: Don't get me worng. I'm all for the space elevator. But if it takes weeks or even months to get to space, it won't entirely replace conventional rockets. There may be an incident where we'll need to get to space quickly.

The space elevator is NOT a Navy SEAL rapid reaction force transport vehicle. It is the equivalent of 18-wheel truckers. The idea is to provide cheap shipping for bulk cargo from the Earth's surface into orbit.

One of the main reasons that the space shuttle has bloated costs is NASA's ulterior motives. As Jerry Pournelle put it, the Shuttle program was designed as a full employment program for ex-Apollo technicians. They made jobs for all the Apollo techs, even though the shuttle didn't need them all.

There is an article about Space Elevator economics here:

http://en.wikipedia.org/wiki/Space_elevator_economics

Re: My mostly hard sci-fi campaign

Will fossil fuels be entirely replaced with other types of fuel by this time?

Keeping in mind that petroleum is also used as a feedstock for the manufacture of plastics and other useful chemicals.

There was a documentary series back in the late 1980's called After The Warming by James Burke. If you can find any episodes it could contain some answers to your questions. I think some of them are on Youtube.

The Tarantula Nebula

http://blogs.discovermagazine.com/badastronomy/2008/12/11/this-tarantula-is-definitely-deadly/

800 light years chock-full of deadly radiation and supernovae. The game master chuckles as they thoughtfully place the coveted MacGuffin smack-dab in the center of the nebula.