what places in the solar system should we visit after mars and moon

[The Blazer]

9 hours ago, dave1904 said:

It would never be cheaper because the demand is not there and will never be. You would need to have the infrastructure to produce fuel and rockets on Mars. Even if they are earth built rockets you will need someone to service them. If you had a colony you would most likely have the propulsion to go from Mars to earth on the same vessel on a regular basis. Producing fuel on Mars is a very unrealistic idea because a self sustained colony is just no benefit to anyone here on earth. We are selfish. Earth has everything mankind needs so it's better to take care of her. If your goal is to mine asteroids you need to bring the resources back to earth and leave anyway. Imo also pointless.

I do agree with you on something: Our home is Earth, and we must take care of her. 

On another space forum, a guy asked me if I prefer to live here on Earth or move to Kerbin... So I answered him: I'll stick with Earth. If Earth is dying, overpopulated, and heating is only because of us, humans. We must stay here and fix the mess we've created, on our own planet. Not just move to another planet and do there the same we've done here. That would make us a parasite civilization...

But going back on your point, when I said cheaper I meant in terms of deltaV, not money. You're probably right, there will probably never be a true demand for a mission to the outer planets unless the cold war breaks out again or Earth is dying on the short-term, so anyway, screw the idea of launch from Mars, but still, a mission to Ceres will be easier than a mission to a Jovian moon.

A Venus balloon-lander seems feasible too.

[Space Nerd]

1 hour ago, The Blazer said:

On another space forum, a guy asked me if I prefer to live here on Earth or move to Kerbin... So I answered him: I'll stick with Earth. If Earth is dying, overpopulated, and heating is only because of us, humans. We must stay here and fix the mess we've created, on our own planet. Not just move to another planet and do there the same we've done here. That would make us a parasite civilization...

I agree with you, but we still need a backup planet just in case if the universe decided to destroy us.

[kerbiloid]

Or the backup planet colonization require technologies which make the planet itself out of purpose.

[dave1904]

2 hours ago, The Blazer said:

I said cheaper I meant in terms of deltaV, not money

Is that not the same thing? 

[Hannu2]

2 hours ago, dave1904 said:

Is that not the same thing? 

It has been, but recent development has decreased cost of dv (=mass to orbit) and that trend seems to continue when SpaceX and Blue Origin get next generation rockets ready. Launch is not any more biggest cost of satellite or probe and when next generation manned ships come int action it is probably not highest cost in manned operations anymore. Cost of life support and (in my opinion too) high safety expectations develop much slower rate than cost of brute force.

[dave1904]

21 minutes ago, Hannu2 said:

It has been, but recent development has decreased cost of......... 

 

There is no way a Lunar base would ever make a mars mission cheaper just like there is no way a Mars base would make an outer solar system mission cheaper. You would need hundreds of missions to ever make it worthwhile. Even if you're trying to save deltaV without money. It would require more deltaV to get the equipment to mars and land it than getting it to where you need straight away. Long term plans do not work for space travel. For all we know the US, nasa, EU, esa and space x will not exist in 30 years. You never get a return in investment. By that time we will hopefully have new engines making those bases useless before they are ever ready. Just like the SLS. 

[The Blazer]

1 hour ago, dave1904 said:

 

There is no way a Lunar base would ever make a mars mission cheaper just like there is no way a Mars base would make an outer solar system mission cheaper. 

I thought the NASA wanted to do just that... Using the Moon as a base to get cheaper to Mars?

[Wjolcz]

7 hours ago, kerbiloid said:

Or the backup planet colonization require technologies which make the planet itself out of purpose.

This is true. If you can launch thousands of tonnes into orbit in a relatively short time period you might as well start making O'Neill cylinders. In those, you can make the climate whatever you like (with much less energy and resources compared to terraforming a planet), keep gravity at healthy levels and shield everything without any fancy magnetosphere gizmos.

Edited February 7, 2020 by Wjolcz

[Codraroll]

6 hours ago, kerbiloid said:

Or the backup planet colonization require technologies which make the planet itself out of purpose.

Which is exactly why we should strive for it. If we can get a whole colony's worth of stuff to Mars and make it survive there, we can, in practice, build a colony anywhere. At least anywhere within a reasonable distance from the Sun, if our chosen technology depends on solar energy in one form or another. The level of self-sustainability needed to achieve this milestone will be greatly appreciated by other industries on Earth as well. The solutions found for the relatively unconventional problems in space travel (say, waste recycling, radiation shielding, photovoltaics, spacesuits, etc.) can have direct application in taking care of Earth as well. 

[dave1904]

1 hour ago, The Blazer said:

I thought the NASA wanted to do just that... Using the Moon as a base to get cheaper to Mars?

No. That is not the plan. The moon base is only testing for long term space habitation. A mars mission would still be launched and assembled in earth orbit or maybe straight to mars. The reality is that nasa is nowhere close to mars. The moon missions are cool yeah but also pointless just like the ISS and space shuttle were. 

[dave1904]

1 hour ago, Codraroll said:

Which is exactly why we should strive for it. If we can get a whole colony's worth of stuff to Mars and make it survive there, we can, in practice, build a colony anywhere. At least anywhere within a reasonable distance from the Sun, if our chosen technology depends on solar energy in one form or another. The level of self-sustainability needed to achieve this milestone will be greatly appreciated by other industries on Earth as well. The solutions found for the relatively unconventional problems in space travel (say, waste recycling, radiation shielding, photovoltaics, spacesuits, etc.) can have direct application in taking care of Earth as well. 

If you were being realistic about a mars colony you would go with reactors over solar. Getting solar to a level that it could sustain a mars colony would be impossible on mars. Solar doesn't even work properly on earth and we do not require life support 24/7 to survive. Just imagine the heating costs at night time when it is -100 degrees. To be fair they have great insulation but still. 

Edited February 7, 2020 by dave1904

[Codraroll]

9 hours ago, dave1904 said:

Just imagine the heating costs at night time when it is -100 degrees. To be fair they have great insulation but still. 

-100 degrees, but also a near vacuum, so there wouldn't be much of a heat exchange with the atmosphere. The limiting factor for insulation on Earth is the air it contains, which means its thermal conductivity can't fall much below ~22 mW/meter*Kelvin. Imagine the insulation being soaked in water so it's wet and poorly insulating, only that it isn't water but air. Advanced thermal insulation materials exist, which achieve a lower thermal conductivity by filling the insulation pores with gas, or even better, gas is pumped out entirely (vacuum insulation - great insulation value, a major chore to build with since you're effectively building with balloons, that have the pressure on the outside as opposed to the inside - poke a hole anywhere in a panel and it's useless).

It should actually be fairly simple to insulate a building on Mars for this reason. You have so little convection that steals heat from the building. I think heat losses to the ground would be high, but it would also be simple to insulate - no ground water to mess things up, so as long as you can space the structure apart from the ground, you'd be good there too. I think even a polystyrene block would suffice.

Also, I wouldn't worry much about heat per se. All the other life support systems you'd need would presumably generate plenty of waste heat. Cooling the colony down might actually be more tricky. Using some sort of heat exchanger with the ground should suffice, though.

[StrandedonEarth]

Yeah, Mars as a stepping stone to the outer system makes no sense. Although, the thought of meeting up with tankers launched from Phobos or Deimos is intriguing....

[Space Nerd]

12 hours ago, dave1904 said:

The moon missions are cool

That's the main reason of why I like space flight.

21 hours ago, kerbiloid said:

Or the backup planet colonization require technologies which make the planet itself out of purpose.

 

14 hours ago, Wjolcz said:

This is true. If you can launch thousands of tonnes into orbit in a relatively short time period you might as well start making O'Neill cylinders. In those, you can make the climate whatever you like (with much less energy and resources compared to terraforming a planet), keep gravity at healthy levels and shield everything without any fancy magnetosphere gizmos.

Well, a giant space station is a "backup planet" to me.

Edited February 8, 2020 by Space Nerd

[dave1904]

16 hours ago, Codraroll said:

-100 degrees, but also a near vacuum, so there wouldn't be much of a heat exchange with the atmosphere. The limiting factor for insulation on Earth is the air it contains, which means its thermal conductivity can't fall much below ~22 mW/meter*Kelvin. Imagine the insulation being soaked in water so it's wet and poorly insulating, only that it isn't water but air. Advanced thermal insulation materials exist, which achieve a lower thermal conductivity by filling the insulation pores with gas, or even better, gas is pumped out entirely (vacuum insulation - great insulation value, a major chore to build with since you're effectively building with balloons, that have the pressure on the outside as opposed to the inside - poke a hole anywhere in a panel and it's useless).

It should actually be fairly simple to insulate a building on Mars for this reason. You have so little convection that steals heat from the building. I think heat losses to the ground would be high, but it would also be simple to insulate - no ground water to mess things up, so as long as you can space the structure apart from the ground, you'd be good there too. I think even a polystyrene block would suffice.

Also, I wouldn't worry much about heat per se. All the other life support systems you'd need would presumably generate plenty of waste heat. Cooling the colony down might actually be more tricky. Using some sort of heat exchanger with the ground should suffice, though.

I still stand by my point that solar is not an option. Its dangerous to because if there is a storm you might go without power for a while.

Couldn't you use the ground as your cooling solution? I don't know a lot about thermal radiation. 

[Bill Phil]

46 minutes ago, dave1904 said:

I still stand by my point that solar is not an option. Its dangerous to because if there is a storm you might go without power for a while.

Couldn't you use the ground as your cooling solution? I don't know a lot about thermal radiation. 

Beamed solar could work - may even go through storms.

[StrandedonEarth]

1 hour ago, dave1904 said:

Couldn't you use the ground as your cooling solution? I don't know a lot about thermal radiation. 

A reversible ground-loop heat pump (main component in an air conditioner) would be ideal for thermal regulation.

 

[magnemoe]

1 hour ago, Bill Phil said:

Beamed solar could work - may even go through storms.

Expensive however. you need to build, launch and maintain them around mars,  will mass more than the mars base. 
Now if you make fuel and oxidizer you could burn that, if its an storm shortly after landing you die. 
Face it if you want to stay on Moon, Mars or the belt and outward you need nuclear. 

Not much of an problem, the small reactors who will be used is smaller than the ones on nuclear submarines, they will not meltdown as their mass is too low. 
Space is so radioactive anyway and its no environmental concerns, just the health of the colonists and the habitates. 

[Bill Phil]

2 hours ago, magnemoe said:

Expensive however. you need to build, launch and maintain them around mars,  will mass more than the mars base. 
Now if you make fuel and oxidizer you could burn that, if its an storm shortly after landing you die. 
Face it if you want to stay on Moon, Mars or the belt and outward you need nuclear. 

Not much of an problem, the small reactors who will be used is smaller than the ones on nuclear submarines, they will not meltdown as their mass is too low. 
Space is so radioactive anyway and its no environmental concerns, just the health of the colonists and the habitates. 

I doubt it’ll mass more than the Mars base - there are some very interesting technologies for light solar in space. 

The real issue is the rectenna and the microwave transmitter...

[The Blazer]

On 2/7/2020 at 9:25 AM, dave1904 said:

 The moon missions are cool yeah but also pointless just like the ISS and space shuttle were. 

Sorry for the long time to reply, but I disagree with you there.

Yes, the whole Apollo program was triggered by a political rivalry, definitively not by science, or the quest for knowledge (and definitively not to get funds back), but it helped in many other ways, like increasing our knowledge of manned space travel.

Same with the Shuttle and ISS, their whole point was, help us study how human-beings can adapt to long times living in space, and that helps us planning the future interplanetary missions. That's their whole point, they didn't achieved too much on their own, but they were the necessary first-step towards something bigger.

[dave1904]

7 minutes ago, The Blazer said:

Sorry for the long time to reply, but I disagree with you there.

Yes, the whole Apollo program was triggered by a political rivalry, definitively not by science, or the quest for knowledge (and definitively not to get funds back), but it helped in many other ways, like increasing our knowledge of manned space travel.

Same with the Shuttle and ISS, their whole point was, help us study how human-beings can adapt to long times living in space, and that helps us planning the future interplanetary missions. That's their whole point, they didn't achieved too much on their own, but they were the necessary first-step towards something bigger.

The ISS is just as political as the apollo missions except that it lacked competition. That is why it failed and apollo succeeded. The shuttle achieved nothing more than launching the biggest waste of money into LEO. The few things we have learned from it could have been done with other far cheaper space stations. The Saturn was capable of launching smaller stations to orbit in one launch. They would have done the job.