Back to the moon...next year

[Mallette]

1 hour ago, hsosdrummer said:

In spaceflight the margins for error are so thin that eventually some people will die going into space, no matter the hardware or the program.

Disagree if you are saying it will always be that way.  It won't, and it's people like Burt Rutan and Elon Musk who are headed towards spaceflight that is routine and safer than being home. 

 

Margins for flying in the atmosphere are just as thin.  And yes, that history was written in blood...but we've learned to make it the safest way to travel.  I would also submit that the submarine is in an environment every bit, if not more, hostile and we've made them extremely reliable.

 

Dave

[hsosdrummer]

2 hours ago, Mallette said:

Margins for flying in the atmosphere are just as thin. 

 

This is simply not true. These engineering margins are to a very large degree dictated by the percentage of vehicle mass represented by fuel, as opposed to the percentage represented by the vehicle itself and its payload. The higher the percentage represented by the vehicle and payload, more robustly it can be designed and the easier it is to build.

 

An airliner is around 40% fuel and 60% airliner and payload, and it operates under 40,000 feet, at speeds under 600 mph and at G loads around 1G. These dictates are comparatively benign, and offer a fair degree of engineering latitude — there are lots of different airliner designs and they can be built from a range of materials. Having 60% of the vehicle’s mass to work with allows engineers a wider margin for error — fudge things a bit and your airliner might not achieve the desired range or payload, but it’s not likely to fall out of the sky. If part of the structure needs strengthening, it can be done with a relatively minor impact on performance.

 

On the other hand, Tsiolkovsky's rocket equation dictates that to place a payload into Earth orbit, a rocket must be at least 83% propellant and only 17% rocket and payload (by mass). And that's using the most energetic propellant available (hydrogen/oxygen). Switch the fuel to kerosene/oxygen (as used by Russian rockets) and the ratio changes to 94% propellant and only 6% rocket and payload. On top of that, the vehicle must operate at altitudes from sea level all the way to the vacuum of space, at speeds over 18,000 mph and at G loads over 3G, and at least part of it must be designed to survive re-entry if you want to get your payload (crew) back safely.

 

When you're designing a vehicle that's at best 83% propellant and only 17% vehicle your engineering margins become razor-thin. There is no way to make the structure more robust lest you upset the fuel/rocket ratio set in stone by Tsiolkovsky, in which case your rocket is guaranteed not to achieve Earth orbit. Your manufacturing processes must be extremely precise or something breaks and your rocket disintegrates under the dynamic stresses of launch. Or part of it explodes 200,000 miles from Earth and dumps most of your breathing oxygen into space. In an airliner, if a large section of the fuselage roof rips off during flight, chances are you can keep flying and land safely. In a rocket, if a piece of foam punches a briefcase-sized hole in your structure you disintegrate during re-entry and everyone aboard dies.

 

Talk to any aeronautical engineer about the difference in margin for error between flying around in the atmosphere under Mach 1 and flying all the way into Earth orbit and back again. They’re different by orders of magnitude. Musk's engineers are aware of all this (and a good deal more, I'm sure).

[richieb]

Hey, if a guy like Musk can develop a payment system (PayPal) that allows me to buy/pay for a tube amp from some idiot half way around the world and have it in a couple days and then design/build cars that have never sniffed a gas fume than I'm sure he will have no problem shooting people to the moon. 

[Mallette]

1 hour ago, hsosdrummer said:

Tsiolkovsky's rocket equation dictates that to place a payload into Earth orbit, a rocket must be at least 83% propellant and only 17% rocket and payload (by mass).

Good grief.  Luckily, Musk doesn't operate on 19th century science and neither do our airlines.  Even if you wish to, safety isn't part of this concept.  We know that an airliner that has a major failure drops like a rock. 

Dave

[hsosdrummer]

On ‎3‎/‎3‎/‎2017 at 7:10 PM, Mallette said:

We know that an airliner that has a major failure drops like a rock. 

 

 

Everyone lived except for a flight attendant who was in the aisle at the time, and the plane landed safely. In space this sort of thing (explosive decompression of the passenger cabin) never works-out that well. The two endeavors (flying in the atmosphere under Mach 1 and flying into Earth orbit) are simply NOT comparable in complexity and risk. Everyone who flies into space, including Elon Musk does so in accordance with Tsiolkovsky's equations — 19th-century, 20th-century or 21st century doesn't enter into it. Newton's laws are 17th-century, but the next time you're driving at 70mph try violating his second and third laws of motion. Even in a Tesla the results won't be pretty. Scotty's famous quote in Star Trek is famous because it's true. You cannot violate the laws of physics. 

[Mallette]

12 minutes ago, hsosdrummer said:

Scotty's famous quote in Star Trek is famous because it's true. You cannot violate the laws of physics. 

Whether in the atmosphere or outside of it.  The above wasn't nearly as bad as Apollo 13, and they survived as well.  Our silent service exists in a comparably hostile environment 24/7 and has had no major incident in decades.  Not sure why you single out space as somehow more difficult or dangerous.  We will not only make it safe, it will be our home...unless we don't act on it and simply become extinct in the womb.  "Go forth and multiply..."  Can't do that here.  Already trashed the place and the only way to fix it is to get off it before there is absolutely nothing left.  Earth is our womb, but we are past gestation and it's time to give Mother a break.  Hard, but necessary. 

 

Dave

[hsosdrummer]

Fortunately for the Apollo 13 crew, their explosion was in the service module, not in the crew cabin, where it would have instantly killed Lovell, Haise and Schweikert.

 

While I agree that ultimately humanity can colonize other worlds, if we think that's what will save us from the destruction we're currently causing to Earth humanity is doomed to die-out here. Taking humans to other worlds in any numbers that would be meaningful to the survival of the species at large will come much too late if we don't take major steps to save this planet right now. Unless of course, you're happy with the notion of humanity being re-populated solely by the descendants of the very, very few who'll be able afford to travel to those new worlds on their own dime.

 

Let me put it this way: humanity is currently on a ship that's sinking at an ever-increasing rate. We currently don't know the location of any other ship capable of supporting Earth's passengers, we currently have no means whatsoever of getting to any new ship, once we find it, and we would have to spend more than all of the treasure on Earth to build and operate this as-yet-unknown means of transportation. Rather that put all our eggs in the "let's find and travel to a new ship" basket, we should instead be putting our eggs into the "let's slow and stop the leak on the Earth ship" basket. We can certainly afford to spend some of our treasure to find the new ship and develop a means of getting to it, but if we do nothing to mitigate the leak we're causing, our ship will be at the bottom of the sea long before we succeed at either of these. 

[Jeff Matthews]

There's plenty on earth.  Next time you are sitting back, enjoying those Klipsch speakers, be thankful for this "rotting" planet of ours.

[hsosdrummer]

I'm very thankful for it. That's why I don't want to see it turned into a sewer simply so a few very rich people can get ever richer.

[Mallette]

2 hours ago, hsosdrummer said:

While I agree that ultimately humanity can colonize other worlds, if we think that's what will save us from the destruction we're currently causing to Earth humanity is doomed to die-out here.

No point in further debate.  You've just said it's hopeless.  I agree.  Forget science for a minute.  I've personally observed Thailand go from 90 percent virgin forest to 80% raped wasteland in only 20 years.  Other places as well, including the American south.  I wept like a baby when I first saw the vandalous destruction for toilet paper of miles of secondary growth forest in my home state and places I grew up in and enjoyed.  And it is not, and will not get better.  It will accelerate...everything we know from history points to that. 

 

However, your conclusion is constructed as a non-sequitur.  If your lifeboat is sinking and you get into a fresh one with supplies, hard to imagine why you are doomed anyway. 

 

Dave

[hsosdrummer]

I haven't said that it's hopeless, I've said that our only hope is to slow how quickly we're trashing the Earth, and that at the rate we're currently trashing it, we won't be able to find another world to live on or figure out how to get there before we've trashed it to the point where it will no longer support us. Our hope lies in our changing what we're doing to this planet, not in finding another planet to live on.

 

You may be right that the problem here on Earth is too far gone for us to solve, and I may be right that we're not going to find somewhere else to live or a way to get there before it's too late. Both of those scenarios sadden my heart. But that doesn't mean that humankind should stop trying to succeed at fixing things from both angles.

[Mallette]

1 hour ago, hsosdrummer said:

I've said that our only hope is to slow how quickly we're trashing the Earth, and that at the rate we're currently trashing it, we won't be able to find another world to live on or figure out how to get there before we've trashed it to the point where it will no longer support us. Our hope lies in our changing what we're doing to this planet, not in finding another planet to live on.

Completely unrealistic.  You are not getting the "womb" analogy.  Are you suggesting re-engineering humans to consume less and not need to reproduce?  While reproduction has slowed, there were less than 2 billion here when I was a child, and now more than 7.  Even slowed that implies over 20 in another 50 years.  The planet only has so much to offer and much is gone already.  Rare earths are essential to our technology and are getting rarer all the time.  No "slow down" will help with that as they are consumed.  And that is only one, relatively small issue.  Many of the rest are MUCH more egregious.  Other places to live, like the moon, Mars, Jovian moons, and such are already within reach and readily accessible by current technology.  Columbus didn't exactly set off an immediate flood and I am certain that naysayers of his day would have been stunned by what had occurred by even a 100 years from that first step in a "new world."  Elon Musk says he can be moving 100,000 per year to Mars before he dies.  He has been much more right than wrong so far.  That's still a drop in the bucket, but implies exponential growth in exocolonization...and hope for human survival we do NOT have here.   

I am a realist, not a space cadet.  No amount of "slowing down" will prevent the inevitable.  The sooner we begin to move out where we belong the sooner we actually become what nature intended, and the sooner this planet can begin to heal.  It CAN heal, but not with constantly expanding human demands.  It's scientifically absurd to believe you can have an infinitely expanding population in a finite space.  If ANY intelligence survives much beyond our current situation it is clear they do not do so on their home world 

Sometime in the future, I dream of a beacon in orbit that says "human home world galactic park...pack it in, pack it out, and leave no trace." 

Dave

[Jeff Matthews]

9 hours ago, Mallette said:

Completely unrealistic.  You are not getting the "womb" analogy.  Are you suggesting re-engineering humans to consume less and not need to reproduce?  While reproduction has slowed, there were less than 2 billion here when I was a child, and now more than 7.  Even slowed that implies over 20 in another 50 years.  The planet only has so much to offer and much is gone already.  Rare earths are essential to our technology and are getting rarer all the time.  No "slow down" will help with that as they are consumed.  And that is only one, relatively small issue.  Many of the rest are MUCH more egregious.  Other places to live, like the moon, Mars, Jovian moons, and such are already within reach and readily accessible by current technology.  Columbus didn't exactly set off an immediate flood and I am certain that naysayers of his day would have been stunned by what had occurred by even a 100 years from that first step in a "new world."  Elon Musk says he can be moving 100,000 per year to Mars before he dies.  He has been much more right than wrong so far.  That's still a drop in the bucket, but implies exponential growth in exocolonization...and hope for human survival we do NOT have here.   

I am a realist, not a space cadet.  No amount of "slowing down" will prevent the inevitable.  The sooner we begin to move out where we belong the sooner we actually become what nature intended, and the sooner this planet can begin to heal.  It CAN heal, but not with constantly expanding human demands.  It's scientifically absurd to believe you can have an infinitely expanding population in a finite space.  If ANY intelligence survives much beyond our current situation it is clear they do not do so on their home world 

Sometime in the future, I dream of a beacon in orbit that says "human home world galactic park...pack it in, pack it out, and leave no trace." 

Dave

If I got this right, we're killing off all the trees, and in order to survive, we need to colonize treeless places like Mars.

[Mallette]

6 hours ago, Jeff Matthews said:

If I got this right, we're killing off all the trees, and in order to survive, we need to colonize treeless places like Mars.

Classic non sequitur, best I can tell.  Or perhaps I just can't figure out what you are talking about.  Trees have everything to do with the survival of Earth, but nothing to do with survival of the human race other than that.  About as nonsensical as saying a baby requires placental fluids to survive and therefore must not be born to place where there are none.  

 

Dave

[Jeff Matthews]

1 hour ago, Mallette said:

Classic non sequitur, best I can tell.  Or perhaps I just can't figure out what you are talking about.  Trees have everything to do with the survival of Earth, but nothing to do with survival of the human race other than that.  About as nonsensical as saying a baby requires placental fluids to survive and therefore must not be born to place where there are none.  

 

Dave

Let me put the puzzle you made together for you. 

 

You said we're destroying all our trees.  We can't survive on this planet without them.  Let's move to a planet with no trees in order to survive.  I am quite sure this is what you said (without realizing it).  It went something like this:

 

I've personally observed Thailand go from 90 percent virgin forest to 80% raped wasteland in only 20 years.  Other places as well, including the American south.  I wept like a baby when I first saw the vandalous destruction for toilet paper of miles of secondary growth forest in my home state and places I grew up in and enjoyed.  And it is not, and will not get better.  It will accelerate...everything we know from history points to that. 

 

In the many other posts, you have noted we need to leave this planet to survive.

[Mallette]

13 minutes ago, Jeff Matthews said:

In the many other posts, you have noted we need to leave this planet to survive.

Jeff, the reasons are manifold and established.  If you or others believe it's possible to sustain an infinitely expanding population in a finite environment, which is the most fundamentally observable issue, then no argument is possible.  Once you accept that, you can look around and begin to see that things are being consumed that cannot be replaced here, things that human life depends on.  And I do not mean toilet paper.

Dave

[Jeff Matthews]

Just now, Mallette said:

Jeff, the reasons are manifold and established.  If you or others believe it's possible to sustain an infinitely expanding population in a finite environment, which is the most fundamentally observable issue, then no argument is possible.  Once you accept that, you can look around and begin to see that things are being consumed that cannot be replaced here, things that human life depends on.  And I do not mean toilet paper.

Dave

I know.  There are 2 primary issues:

 

1.  It's just as hard to predict the weather 100 years from now as it is to predict the population.  We have average growth rates, but there are periods in our history where they plummeted due to plague, etc.  Nevertheless, it's fair to assume a constant rate to the extent you might be able to plan for it.

 

2.  If we run out of trees and toilet paper on earth, how in the heck are we going to get it on the moon?  Are we going to bring cattle and let them graze on Mars?  Just exactly where will we get our water?  

 

It's nice to dream, but there's a long, long, long way to go.  Travel is one thing.  Settling colonies is another.

[babadono]

26 minutes ago, Jeff Matthews said:

Settling colonies is another.

Settling self sustaining colonies is another.

[mungkiman]

3 hours ago, Mallette said:

If you or others believe it's possible to sustain an infinitely expanding population in a finite environment, which is the most fundamentally observable issue, then no argument is possible.  Once you accept that, you can look around and begin to see that things are being consumed that cannot be replaced here, things that human life depends on.  And I do not mean toilet paper.

Dave

 

It's a bubble. Once burst, the correction will be ugly, but I bet that happens before sustainable colonization occurs anywhere else...

 

[billybob]

Quote

Time has come today there Dave. Private entrepreneurs see the writing in the stars. High time we got back to doing all the good stuff like, planning the survival of the human() race. Energy needs may indeed come to us one day, given the rare isotope(s) to be maybe found there besides the one. I say, do please carry on towards any other likely semi-inhabitable out there. Thanks for the topic.