Venusian lander

[kerbiloid]

23 minutes ago, Flying dutchman said:

The gas would never exceed 450c.

The cooling system should heat the gas hotter than the atmosphere is, to dissipate the heat waste.

[Flying dutchman]

43 minutes ago, kerbiloid said:

The cooling system should heat the gas hotter than the atmosphere is, to dissipate the heat waste.

Not at all. What if you have gas coming in that is already cooled to 20°c. Why on earth would you heat up that gas to exceed the ambient temperature when the actual heat is dissipated 50km above the base where the ambient tenperature is around 20°c...

 

Yes of course the gas would heat up when running through the base's cooling system. But since the heat is not dissipated at the surface but at 50km altitude why would it ever need to exceed 450°c?

[Lisias]

15 minutes ago, Flying dutchman said:

Yes of course the gas would heat up when running through the base's cooling system. But since the heat is not dissipated at the surface but at 50km altitude why would it ever need to exceed 450°c?

To avoid taking heat from the environment while the gas goes up. You want to pump heat from your facilities, not from the low atmosphere.

[kerbiloid]

22 minutes ago, Flying dutchman said:

What if you have gas coming in that is already cooled to 20°c. Why on earth would you heat up that gas to exceed the ambient temperature when the actual heat is dissipated 50km above the base where the ambient tenperature is around 20°c... 

Friction loss in a pipe is proportional to fluid velocity (in laminar flow).
So, if the "air" flow is ~150 m/s, and the pipe is enough wide, it takes 30000/150 = 200 s to get up or down.
Also the pipe surface is enormous compared to the habitat, as the pipe diameter/length ratio can not be low, otherwise the friction will just stop the gas motion and require enormous power for the pump.

As a result, the pipe volume would be many times greater than the habitat volume.

Also I'm just trying to keep existing solutions where they are available. Active cooling exists, 30 km pipes - no.

Edited August 4, 2019 by kerbiloid

[Flying dutchman]

1 minute ago, kerbiloid said:

Friction loss in a pipe is proportional to fluid velocity (in laminar flow).
So, if the "air" flow is ~150 m/s, and the pipe is enough wide, it takes 30000/150 = 200 s to get up or down.
Also the pipe surface is enormous compared to the habitat, as the pipe diameter/length ratio can not be low, otherwise the friction will just stop the gas motion.

As a result, the pipe volume would be many times greater than the habitat volume.

Also I'm just trying to keep existing solutions where they are available. Active cooling exists, 30 km pipes - no.

Yes but this is all hyphothetical as i stated before.

[Terwin]

21 hours ago, Flying dutchman said:

Yes but this is all hyphothetical as i stated before.

As the tallest man-made structure(Burj Khalifa) is all of 830m tall, a 30km tall pipe seems more like a fantasy than a hypothesis, especially when you add in the 700km/hr winds, acidic atmosphere, and high temperatures.

Without that pipe, your habitat AC unit will need to pump away your excess heat over a 430 degree gradient, sort of like pumping water out of a 430' deep well, and just like pumping water out of a well, there is a minimum amount of power it will take to pump that heat/water out of your habitat/well.(using two pumps to pump the water out in a couple of easier stages does not reduce the amount of potential energy being added to the water, and thus does not reduce the minimum energy to pump it out of the well)

[Lisias]

19 minutes ago, Terwin said:

As the tallest man-made structure(Burj Khalifa) is all of 830m tall, a 30km tall pipe seems more like a fantasy than a hypothesis, especially when you add in the 700km/hr winds, acidic atmosphere, and high temperatures.

No more than floating habitats on the warm high atmosphere of Venus.

And yet..

NASA Concept. Click on the image for more information.

[kerbiloid]

One room per airship, absolutely hostile for any docking operations.

Airship drones should be cloud catchers servicing the ground base ISRU.

[Terwin]

1 hour ago, Lisias said:

No more than floating habitats on the warm high atmosphere of Venus.

And yet..

NASA air-ships:

* Dirigibles of various sizes have and do exist on earth.  They are easy enough to make that some exist primarily for advertising(ever seen the Goodyear blimp at a sporting event?)

* if the 350 km/h winds at height have generally low turbulence, then the projected dirigibles should not care about the absolute wind-speed so long as they don't try to maintain a position relative to the ground(which would be impossible).

* at human survivable temperatures and pressure, the acidity of the atmosphere is mostly at irritant levels and not hard to protect against

30 km tall pipe:

* no vertical structure of even 1/30 this height has been constructed to date

* these pipes would need to deal with the full energy of super-heated, acidic, super-dense 700km/h winds, something no structure on earth has even tried to deal with(even Cheyenne Mountain might not be able to handle those conditions)

* at 90 atmospheres any atmospheric acid will be much more concentrated, and at 450 degrees c chemical reactions will be much more vigorous 

Comparison:

NASA Dirigibles on Venus take something known to work and with which we have great practical experience and put them in a situation where they may or may not require additional assistance(a coating to resist the acid, and possibly something to deal with the turbulence, if any).

Your 30km tall pipe is pure fantasy even on earth, so making it in the much harsher environment of Venus is a non-starter.

 

Even so, The blimps seem only vaguely plausible, as I would expect turbulence in the 350 km/h winds which would quickly rip them to shreds.

[magnemoe]

1 hour ago, kerbiloid said:

One room per airship, absolutely hostile for any docking operations.

Airship drones should be cloud catchers servicing the ground base ISRU.

Sample returns, Balloon goes up airship releases drones who catch it and return to airship who load it into missile who takes it to orbit. 

You will have manned present in orbit say a starship or similar to avoid light speed lag and collect sample.
ISRU don't work then its way cheaper to transport stuff from earth surface to low Venus orbit than getting it from hell. 

 

[kerbiloid]

13 minutes ago, magnemoe said:

Balloon goes up

From the Venusian surface?
Low density is required to float, but thick and heavy envelope to withstand the external pressure turns it into a lead zeppelin.

13 minutes ago, magnemoe said:

and return to airship who load it into missile who takes it to orbit. 

8 km/s to deorbit and slowly lower to 60 km + 8 km/s to orbit, and docking/undocking to a tiny platform hanged behind a balloon many times wider, with no option to miss?

I'm afraid, any Venusian airship is a one-way ticket to the blue ground.

Edited August 5, 2019 by kerbiloid

[Lisias]

49 minutes ago, Terwin said:

Your 30km tall pipe is pure fantasy even on earth, so making it in the much harsher environment of Venus is a non-starter.

No, sir. Science Fiction - no fantasy.

[magnemoe]

6 minutes ago, kerbiloid said:

From the Venusian surface?
Low density is required to float, but thick and heavy envelope to withstand the external pressure turns it into a lead zeppelin.

8 km/s to deorbit and slowly lower to 60 km + 8 km/s to orbit, and docking/undocking to a tiny platform hanged behind a balloon many times wider, with no option to miss?

I'm afraid, any Venusian airship is a one-way ticket to the blue ground.

Not saying its easy, an permanent station around Saturn is probably easier and also more rewarding. 

You could probably catch the drone in an net and winch it in. 
Launcher would be an small icbm who you fire inside the airship. replace the warhead with an extra stage or two. 

 

[kerbiloid]

9 minutes ago, magnemoe said:

Launcher would be an small icbm who you fire inside the airship

As Venusian gravity is close to the terrestrial one, a small ICBM = a very small payload, ~1/20 of launch mass.
So, to return 1 t of samples, a ~30 t rocket is required.

+ twice of that for a chopper platform.

Precisely deorbiting and docking/catching a ~80 t chopper under a huge lightweight unstable balloon is very untrivial.
Unlikely it works.

[magnemoe]

5 minutes ago, Lisias said:

No, sir. Science Fiction - no fantasy.

Some differences, water has an high buoyancy, stuff like wood float in it. 
Oil platforms are massive 10.000 ton is kind of small, for floaters  on some kilometer depth you fast get close to 100K ton. 
The evolved over some generations with huge economical gains. 
Its two days away with ships and is serviced by loads of ships. 

Please airlift this

It did not fit in the Suez canal so it would save some time  I worked on the project. 

Venus is not going anywhere, lets do some other stuff the next 1000 years like becoming an K1+ civilization and industrialize the orth cloud. 
Then dropping large and fast stuff on it to spin it up and give  water, sunshade to cool it down, electricity from shades drives mass drivers who remove co2, give some to Mars. Then  teraform. 

12 minutes ago, kerbiloid said:

As Venusian gravity is close to the terrestrial one, a small ICBM = a very small payload, ~1/20 of launch mass.
So, to return 1 t of samples, a ~30 t rocket is required.

+ twice of that for a chopper platform.

Precisely deorbiting and docking/catching a ~80 t chopper under a huge lightweight unstable balloon is very untrivial.
Unlikely it works.

Was thinking of some kilogram. 
You only have an small sample area after all. 

Mars sample return plans is less than an kilogram, yes Musk disagree but Mars or Pluto sample return is easy compared to Venus. 

[kerbiloid]

25 minutes ago, magnemoe said:

Was thinking of some kilogram. 
You only have an small sample area after all. 

Ok, let it be Pegasus. 0.5 t of payload, 20 t of total mass. 
Can't remember if there were successful launch vehicles of lesser mass, as rocket engines have finite size, and air drag is higher for lighter bodies.

+ chopper mass.
+ any successful helicopter attachment to an airship?
+ any successful helicopter flights after deorbiting and aerobraking?

25 minutes ago, magnemoe said:

Mars sample return plans is less than an kilogram, yes Musk disagree but Mars or Pluto sample return is easy compared to Venus. 

But I don't mean just flagplanting and footprinting.
I mean a long-term base, maybe a permanent one.

Another point of the heavy Venusian base is: if a, say, 100 m large habitat can survive on Venus, it can survive on any solid body, and even at 1000 m underwater depth on the Earth.
And as such base can't be landed just by aerobraking (M/S to high), it needs landing engines.
And as such engines should produce T/W > 1 to slow the landing, they also can lift it up and deliver to the sky.
Obviously with nuke-powered thermal nozzles pumping the atmospheric gas.

And as the Venusian up/down requires much greater delta-V than a trivial interplanetary flight, it's a strong interplanetary ship, landing on any place in Solar System, including the Venus, and staying there as long as desired.

***

Let's call this project "Ishtar", because of Venus, and because of crown of flames around the base (the cooler exhaust), and the Ishtar Land on Venus as the best place for it.

If make its stronger version, enough strong for the Mariana Trench, it can land/splash/dive almost everywhere.
Let's call this case "Aphrodite", because it can appear everywhere from the ocean.

***

Obviously, enough powerful engines and reactors are required, but here I was observing one part of the problem, the possibility of long-term staying on Venus.
 

Edited August 5, 2019 by kerbiloid

[Lisias]

2 hours ago, magnemoe said:

Some differences, water has an high buoyancy, stuff like wood float in it. 
Oil platforms are massive 10.000 ton is kind of small, for floaters  on some kilometer depth you fast get close to 100K ton. 
The evolved over some generations with huge economical gains. 
Its two days away with ships and is serviced by loads of ships. 

Please airlift this

Venus atmospheric pressure is up to 90 times the Earth's. Or 90 * 1013.25 millibars = 91.192,5 millibars.

The Pressure on Earth's oceans at 100m deep are 9.81 bar, or ~9.810,00 millibars. 10 times less than Venus' atmospheric pressure.

But wait, it's the density that matters, right?

Water has a density of 997 kg/m³. Our atmosphere is 1.2kg/m³ .

Venus' atmosphere has a density of 5240 kg/m³. ~5.2 times denser than water. Or ~4.320,33 more denser than our atmosphere.

Do you know what? Pretty feasible, if we manage to shove all that steel on that planet in one piece.

 

(Copyeur und Pasteur is a dangerous technique on scientific essays)

Edited August 5, 2019 by Lisias
uugh...

[kerbiloid]

1 hour ago, Lisias said:

Venus' atmosphere has a density of 5240 kg/m³.

???

67 kg/m³.

Edited August 5, 2019 by kerbiloid

[Lisias]

7 minutes ago, kerbiloid said:

???

67 kg/m³.

UUUGH!!! 5240 is the mean density of the planet!!! #facepalm I copied the wrong value and applied it mechanically without really thinking on the thing. Ok. Let's try again.

Water has a density of 997 kg/m³. Our atmosphere is 1.2kg/m³ .

Venus' atmosphere has a density of 67 kg/m³. ~14.8 times less denser than water. But yet 55.8 times denser than our atmosphere.

Not feasible at all for that monster or anything remotely near that, but Venus would withhold floating structures way heavier than our atmosphere.

(thinking about what I'm writing is a nice habit I should exercise more regularly.)

[Flying dutchman]

4 hours ago, Terwin said:

NASA air-ships:

* Dirigibles of various sizes have and do exist on earth.  They are easy enough to make that some exist primarily for advertising(ever seen the Goodyear blimp at a sporting event?)

* if the 350 km/h winds at height have generally low turbulence, then the projected dirigibles should not care about the absolute wind-speed so long as they don't try to maintain a position relative to the ground(which would be impossible).

* at human survivable temperatures and pressure, the acidity of the atmosphere is mostly at irritant levels and not hard to protect against

30 km tall pipe:

* no vertical structure of even 1/30 this height has been constructed to date

* these pipes would need to deal with the full energy of super-heated, acidic, super-dense 700km/h winds, something no structure on earth has even tried to deal with(even Cheyenne Mountain might not be able to handle those conditions)

* at 90 atmospheres any atmospheric acid will be much more concentrated, and at 450 degrees c chemical reactions will be much more vigorous 

Comparison:

NASA Dirigibles on Venus take something known to work and with which we have great practical experience and put them in a situation where they may or may not require additional assistance(a coating to resist the acid, and possibly something to deal with the turbulence, if any).

Your 30km tall pipe is pure fantasy even on earth, so making it in the much harsher environment of Venus is a non-starter.

 

Even so, The blimps seem only vaguely plausible, as I would expect turbulence in the 350 km/h winds which would quickly rip them to shreds.

I guess you are all right and i am wrong. 

 

[Terwin]

1 hour ago, Flying dutchman said:

I guess you are all right and i am wrong.

You're not quitting are you?

I'm here to learn things and have an intellectual debate about theories.

That does not work so well unless you come back and show me the mistakes in my arguments.

[Flying dutchman]

7 hours ago, Terwin said:

You're not quitting are you?

I'm here to learn things and have an intellectual debate about theories.

That does not work so well unless you come back and show me the mistakes in my arguments.

I will get back to you about this and counter some arguments. I was a little frustrated yesterday due to personal matters. Won't be until tomorrow though since today i'm driving back from my holliday.