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2023-11: Warosu is now out of extended maintenance.

/sci/ - Science & Math

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6217823 No.6217823 [Reply] [Original]

Based on moore's law, how long will it take us to get to a point where we're able to make serious off earth trips. To mars, and maybe deeper into the solar system.

>> No.6217838

>>6217823
That has literally nothing whatsoever to do with Moore's Law.

But, in my estimation, somewhere between 10 - 100 years.

Also, why only go "deeper into the solar system" ? The inner solar system (Venus and Mercury) are where all the most interesting colonization prospects are. All the outer solar system has is Mars, the Asteroids, and Saturn's moons and delicious antimatter. (Jupiter has altogether too much radiation to be useful.)

>> No.6217910

>>6217823
>Based on moore's law

Sigh... ignoring.

>how long will it take us to get to a point where we're able to make serious off earth trips.

The current problem with making off earth trips is that you have to get into orbit around the earth first (basically), which means that your vehicle not only has to be powerful enough to propell itself above the atmosphere (200+ miles up) but it also has to achieve orbital velocity (about 7 kilometers per SECOND)

Now, in order to make a vessel that will accelerate QUICKLY, it mus be light, because a heavy vessel takes more energy to accelerate.

However, in order to make a vessel that will accelerate for enough time to reach those sorts of speeds, it requires a LOT of fuel...

Fuel which weighs quite a bit....

Which makes your ship weigh more, and accelerate less quickly.

Which means that you need a bigger engine and more fuel....

Which adds more weight to your ship....

Etc, etc, etc....

So, anyways, we have the space shuttle, and prior to its decommissioning, was a pretty efficient (comparatively) way to get people INTO orbit (not past orbit... just INTO orbit)

However, due to the cost of rocket fuel, matinance, replacement parts, labor, solid rocket fuel, etc... it cost about 10,000 - 20,000 dollars per POUND to put something in orbit.

Modern orbital insertion systems (rockets) have decreased this cost slightly, but they are still thousands of dollars per pound.

>> No.6217918

>>6217910
Now, keep in mind, this is all JUST TO GET INTO ORBIT, not anywhere past that.

Lets say that you use Billions of dollars to construct a vehicle IN ORBIT (launching a little bit at a time) and then fully fuel it up... Right?

Okay, so in order to get from earths sphere of influance (gravity) to another planet, (planets which are moving relative to the earth, mind you)

Let's say mars.... right?

On closest approach, mars is still about 100 million kilometers away.

Now, traveling at a measly 7 kilometers per SECOND (orbital speed) it would take you 165 DAYS to reach mars.

Now, First off, you are going to need to bring PLENTY of oxygen so that you don't suffocate... AT LEAST a years worth (165 days there, 165 days back +intermediate time)

Take a look at the wiki on diving and such to get an Idea of how much oxygen a person consumes in a year.

Next, you are going to have to bring water, and water filtration systems, so that you don't die of thirst.

Next, you are going to have to bring a years worth of food.

Next, you are going to have to bring along some shielding so that the cosmic radiation doesn't kill you, and shielding weighs quite a bit.

All of this stuff adds weight, which requires larger engines, and more fuel... etc...

Which means that you have to spend even MORE money to put stuff into orbit....

I think you may be starting to get the general Idea now....

>> No.6217930

>>6217918
Technically speaking... yes... we CAN put a VERY FEW people on another planet with current tech.

Bad news is, it would cost something like $50 million dollars per pound of person.

Take a look at the mars rover, for example... that think weighed like... 10-20 pounds maybe?

And they sent it on a VERY SLOW trajectory towards mars, that took like, 2 years or something to finally get there.

Of course, that was fine for the robot, it doesn't need to breathe, or eat, or drink, or sleep, or whatever....

The mission total to get that 10-20 lb rover to mars was something like $50,000,000... and I would say that at least 80% of the cost of that was rocket fuel..... and it took a long ass time to get there, too.

>> No.6217944
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6217944

>>6217930
Currently, there are a few different areas of research involved in getting the cost of orbital insertion down to a reasonable level.

Like this Spaceplane (Skylon) that would cut the fuel cost of orbital insertion by a large amount.

http://en.wikipedia.org/wiki/Skylon_%28spacecraft%29

Next, we have Extremely high exhaust velocity engines that would also cut the amount of fuel that you would need to bring along (and by that metric, also cut the weight of your orbit-to-orbit ship

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

>> No.6218218

>>6217930
Most os what you said is either innacurate or simply massively wrong. Rocket fuel is extremely inexpensive compared to the layncher and its payload.

>> No.6219039

>>6217918
A little help in that department:
http://www.nasa.gov/offices/oct/early_stage_innovation/niac/2012_phase_I_fellows_flynn.html
Addresses shielding, air, water, and food.

>> No.6219053

>>6217823
>Implying we ever get to the moon.

>> No.6219067

>>6217944
There are a couple of tricks we could use to make orbital launch a lot cheaper by using space resources.

One is momentum transmission. By throwing liquid oxygen from the moon (produced and launched using solar power), we would have a supply of mass in orbit. Releasing an aimed stream of droplets would allow a capsule to be "reverse aerobraked" into orbit.

Another is energy transmission. For instance, we could have solar power collectors in orbit, with fast-discharge batteries and sodium plasma beam projectors. The orbital vehicle would boost out of atmosphere by conventional means, and then receive energy through a magnetic scoop, and channel the sodium plasma into an argon or ammonia stream for a high Isp, high thrust boost to orbit.

>> No.6219079

>>6219067
>>>/v/

>> No.6219104

>>6217930
>80% of the cost was rocket fuel

Do you have any idea what rocket fuel actually is? The shit's cheap as dirt.

The Atlas 5, which it was launched on, is mostly LOX/RP-1 and LOX/LH2 . LOX - liquid oxygen - is astonishingly cheap, literally in the cheap-as-dirt range. RP-1 , while relatively expensive, isn't exactly costly either - it's just kerosene. And liquid hydrogen? About three bucks a kilogram. (And hydrogen isn't exactly dense, so that's a pretty big kilogram.)

The fuel is absolutely not a major percentage of the monetary cost of a rocket. It makes up most of the mass, but it's VERY cheap.

It's the rocket ITSELF which is expensive.

>> No.6219108
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6219108

>>6217823
About one hour, if you have lysergic acid diethylamide ready at hand.

>> No.6219155

>>6217838
You crazy? There's so much more in the outer solar system! There's practically nothing in the inner solar system comparatively.

>> No.6219275

>>6219155
Outer solar system:

>Mars (Decent spot for colonization.)
>Asteroids (Useful.)
>Jupiter and assorted moons (pretty to look at from a safe distance, but a radiation-blasted hellhole. Not particularly useful.)
>Saturn and assorted moons (Interesting and possibly useful. Good antimatter harvesting spot, too.)
>Assorted other way-out frozen fuckballs and Kupier rocks (too cold and dim and far-out to be interesting)

Inner solar system:
>Delicious delicious solar power (VERY useful)
>Mercury (Arguably a better colonization spot than Mars)
>Venus (Also arguably a better colonization spot than Mars - not the surface, but for balloon colonies 50 km up, where the conditions are the most Earthlike you'll find anywhere outside Earth.)

Civilization requires energy, and the inner solar system has that in vast quantities from solar power - far more than the outer system.

>> No.6219301

>>6219275

Wind power might be of use in the outer solar system considering how severe the winds get.

>> No.6219305

>>6219275
Yeah, but there's just so much more matter in the outer solar system to use, and much of it is easily accessible. You also forget the Oort cloud and all the juicy comets to harvest. Granted that we eventually master fusion, there's enough fuel in the outer solar system to make solar power secondary.

Of course, this relies on fusion technology, which, as far as interplanetary science goes, isn't that far-fetched.

>> No.6219310

>>6219305
Granted we master fusion and space habitats, that is, but I was taking that for granted in this conversation.

>> No.6219334

>>6219310
I was not.

>> No.6219341

>>6219334
Well, then you're taking other scientific advances for granted. Space habitats is one.

Probably the only one, actually. Maybe a few mechanical ones are different, too, like the balloon cities.

>> No.6219343

Let me derail the topic, do you think that we will ever be able to go local stars? Or at least outside the Oort?

I think we will never do that just because of the vast distances and the energy requirement.

IMO the apex of the human civilazition will be when we fully colonize all the solar system and that will be it.

Unless someone invents a FTL travel... But then the energy requirement would be so high that it wouldbe still impractical to even to the nearest stars..

To OP

I don't see it happening in at least 50 years.. Not because of the technical difficulties but because of cost.

>> No.6219346

>>6217838
>The inner solar system (Venus and Mercury) are where all the most interesting

>> No.6219350

>>6219334
Also, re: the Oort cloud - remember that radiation in space is a severe issue, and that it's going to take a looooong time to get there. So a vessel to carry anyone to the Oort cloud is going to require truly astronomical quantities of fuel and life support, along with an incredible mass of shielding, to do... what? Without a gravity well out there, you're going to be living in a rotating space habitat. And the ship it takes to get you there is going to have to be able to go long enough and maintain itself for long enough and recycle things with enough efficiency that it's going to be ... a rotating space habitat with an absolutely enormous fuel tank strapped on.

In which case, why bother with the trip to the Oort cloud, instead of staying in the relatively-inner system around the asteroid belt, with the same resources, and getting exactly the same experience without needing to buy a huge fuel tank?

The only reason to move to the Oort cloud is if you 1) really really REALLY need privacy, or 2) the asteroid belt has become so crowded / stripped of resources that you HAVE to move (which will be not for a very, very long time.)

>> No.6219359

>>6219104
doesn't the mass inadvertently make it expensive?

>> No.6219389

>>6219350
Well, the idea that I have is that we don't need that much rocket fuel if we utilize Lagrange points to the max. It would take hundreds of years for sure, practically, and you'd be sitting in a space habitat. But that's the point. What's wrong with living in a rotating thing with your friends and family? Generation ships get stigmatized for no good reason.

And okay, maybe a few more advances will be necessary. I've heard plastics can get you pretty good radiation shielding for their weight, so that might be an option. And recycling will have to be developed further, although it's pretty good even now.

>> No.6219394

>>6219389
If you could mimic an ecosystem in space, that would be enough for recycling. What you lost could be supplemented by whatever you pick up.

>> No.6219417

>>6219305
>Yeah, but there's just so much more matter in the outer solar system to use, and much of it is easily accessible. You also forget the Oort cloud and all the juicy comets to harvest.

We don't go to the comets and asteroids, we bring them here.

Send a small unmanned ship there and with a little of controlled impulse and a lot of calculus you make their orbit unstable enough to send them to us.

>> No.6219427

>>6219053
Precisely, it will be unlikely things will wind down smoothly in the next 50 years. Too much TV.

>> No.6219468

Moore's Law is no longer true and hasn't been for a few years now.

>> No.6219493

The top 1% (w.r.t wealth) will consider getting off of this planet when it's nearing its end.
Space exploration doesn't 'pay out'; debating an estimated time is pointless..

>> No.6219675
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6219675

>>6217823
>how long will it take us to get to a point where we're able to make serious off earth trips

Already happening.