NASA: Let's Explore Venus in Solar Zeppelins and Build Cloud City There

""The vast majority of people, when they hear the idea of going to Venus and
exploring, think of the surface, where it's hot enough to melt lead and the
pressure is the same as if you were almost a mile underneath the ocean," NASA's
Chris Jones told IEEE. "I think that not many people have gone and looked at
the relatively much more hospitable atmosphere and how you might tackle
operating there for a while."

However, at a height of around 50 km the atmosphere thins and cools to what one
would find here on Earth, which is exactly where NASA's High Altitude Venus
Operational Concept (HAVOC) would operate. The plan is to first launch a 31-
meter robotic airship to perform initial observations and ensure that the
secondary, manned mission would have a fair chance of success.

NASA would then follow up with a 30-day 2-manned mission aboard a 130-meter,
solar-powered airship with a small cabin slung beneath the helium-filled
dirigible. Then, perhaps, a year-long mission and, if everything goes well,
eventually a permanent floating outpost like a real life Cloud City. Though, as
you can see in the video above, just getting the necessary gear there will be
an enormous challenge and, for the manned missions, we'd have to send a pair of
spacecraft--the first with the airship, the latter with the crew. We can't even
get our Mars rovers to stop drawing dicks in the sand, and NASA really thinks
we're ready to start building floating towns and letting Billy Dee Williams
wear a cape again? Man I hope they're right because that's going to be awesome.
The capes, I mean."

See:

http://gizmodo.com/nasa-lets-explore...d-c-1672805652

In article ,
says...

""The vast majority of people, when they hear the idea of going to Venus and
exploring, think of the surface, where it's hot enough to melt lead and the
pressure is the same as if you were almost a mile underneath the ocean," NASA's
Chris Jones told IEEE. "I think that not many people have gone and looked at
the relatively much more hospitable atmosphere and how you might tackle
operating there for a while."

However, at a height of around 50 km the atmosphere thins and cools to what one
would find here on Earth, which is exactly where NASA's High Altitude Venus
Operational Concept (HAVOC) would operate. The plan is to first launch a 31-
meter robotic airship to perform initial observations and ensure that the
secondary, manned mission would have a fair chance of success.

NASA would then follow up with a 30-day 2-manned mission aboard a 130-meter,
solar-powered airship with a small cabin slung beneath the helium-filled
dirigible. Then, perhaps, a year-long mission and, if everything goes well,
eventually a permanent floating outpost like a real life Cloud City. Though, as
you can see in the video above, just getting the necessary gear there will be
an enormous challenge and, for the manned missions, we'd have to send a pair of
spacecraft--the first with the airship, the latter with the crew. We can't even
get our Mars rovers to stop drawing dicks in the sand, and NASA really thinks
we're ready to start building floating towns and letting Billy Dee Williams
wear a cape again? Man I hope they're right because that's going to be awesome.
The capes, I mean."

See:

http://gizmodo.com/nasa-lets-explore...d-c-1672805652

Unless someone has figured out how to deliver something of a like or
similar nature to a fully-fueled Titan II to a dirigible in flight, this
would be a one way trip. Now let's see, that's on the order of 300
tons. The Hindenberg had a useful load of 5 tons. Not much that can go
wrong here, nosirree.

If we were to keep the NASA appropriation flat, cancel SLS, take the hit to unroll that program, then refocus on what *could* be done with the money, it's mind boggling.

In priority order:

1) Restore full funding to CCdev with short and long term objective of ISS resupply and ISS crew and then followed by cargo and crew to LEO on-demand capacity.

2) Orbiting refueling depots for deep space operations.

3) Standard transportation architecture that leverages ideas such as the Aldrin Cycler and item #2 above to reduce cost for uncrewed missions to the inner planets. Thus making them far less costly to execute than today and hopefully on a more frequent basis. It's insane to mount these missions literally from the "ground up", requiring EVERYTHING launch on a single ELV EACH TIME we wish to fly one.

3) Build out of new space station along lines of Nautilus-X. Starts out as a LEO laboratory, but with build outs that eventually enable it to become the crew habitation module for interplanetary ventures.

Once we've built out this type of LEO and NEO infrastructure we can reasonably start talking about mounting more exploratory missions to the Moon, Venus & Mars.

And if an NGO wants to fund a colonization attempt, they should be free to be able to contract to use this infrastructure as well.

Dave

At 50 km altitude the atmospheric pressure on Venus is 1 bar. The same as it is on Earth. The temperature is around freezing - 0 celsius! The atmosphere is mostly carbon-dioxide. That means its density is 2.01 kg/m3.

http://upload.wikimedia.org/wikipedi...atmosphere.svg

By comparison, Earth's atmosphere at the surface is 1 bar and its density is 1.22 kg/m3 - since it is composed of 72% nitrogen and 28% oxygen. It also has some water vapor, a tiny amount (400 ppm) of CO2. Room temperature is 22 celsius. Its warmer too!

This means that an air tight tank entering the Venusian atmosphere, could be made to float! 0.79 kg of lift is obtained for every cubic meter of volume filled with oxygen nitrogen atmosphere.

A 124 meter diameter inflatable sphere pressurized to 1/10th atmosphere with 121 tonnes of LOX/LN2 lifts 79 tonnes of structure. 50 tonnes for the balloon and hardware. 29 tonnes for the External Tank like airframe with aerospike engine.

The atmosphere is 3.5% Nitrogen and 150 ppm sulphur dioxide, 25 ppm water vapour, and clouds of H2SO4. Sunlight averages 2,617 W/m2 above the cloud tops. A collector built inside a transparent envelope intercepts 31.7 MW of solar energy. This is sufficient to extract nitrogen from the atmosphere along with water vapour, and H2SO4 reducing it to H2O, O2, and elemental sulphur, so that the envelope fills to a higher pressure as the tank that brought the original gases from Earth fill with 790 tonnes of LOX/LH2!

Seven of these tanks are sent independently to Venus and arrive at the planet and enter the atmosphere. The interior of one of the balloons have a habitat built into it, which is part of a return capsule.

A deep sea diving suit - is similar to the sort of suit needed for those living in the upper atmosphere to dive to the surface and return.

https://www.youtube.com/watch?v=5Zub-8BZaa4

Humaniform robots driven by a human wearing an exoskeloton that measures body position and provides feedback from the remotely controlled robot - is another way to explore the Venusian surface at relatively low risk from the cloud capsule.

Over a relatively short period of time, the tanks are filled with hydrogen and oxygen using gases extracted from the Venusian atmosphere. They then join up into a seven element 3 stage launcher, that fires from its balloon perch. Only one of the seven elements escape Venus and fly back to Earth. However, the other seven elements return, and glide back to their launch balloons, where they dock with them, and are refilled.

On Friday, December 19, 2014 10:21:00 AM UTC-8, J. Clarke wrote:
In article ,
says...

""The vast majority of people, when they hear the idea of going to Venus and
exploring, think of the surface, where it's hot enough to melt lead and the
pressure is the same as if you were almost a mile underneath the ocean," NASA's
Chris Jones told IEEE. "I think that not many people have gone and looked at
the relatively much more hospitable atmosphere and how you might tackle
operating there for a while."

However, at a height of around 50 km the atmosphere thins and cools to what one
would find here on Earth, which is exactly where NASA's High Altitude Venus
Operational Concept (HAVOC) would operate. The plan is to first launch a 31-
meter robotic airship to perform initial observations and ensure that the
secondary, manned mission would have a fair chance of success.

NASA would then follow up with a 30-day 2-manned mission aboard a 130-meter,
solar-powered airship with a small cabin slung beneath the helium-filled
dirigible. Then, perhaps, a year-long mission and, if everything goes well,
eventually a permanent floating outpost like a real life Cloud City. Though, as
you can see in the video above, just getting the necessary gear there will be
an enormous challenge and, for the manned missions, we'd have to send a pair of
spacecraft--the first with the airship, the latter with the crew. We can't even
get our Mars rovers to stop drawing dicks in the sand, and NASA really thinks
we're ready to start building floating towns and letting Billy Dee Williams
wear a cape again? Man I hope they're right because that's going to be awesome.
The capes, I mean."

See:

http://gizmodo.com/nasa-lets-explore...d-c-1672805652

Unless someone has figured out how to deliver something of a like or
similar nature to a fully-fueled Titan II to a dirigible in flight, this
would be a one way trip. Now let's see, that's on the order of 300
tons. The Hindenberg had a useful load of 5 tons. Not much that can go
wrong here, nosirree.

A Blimp might work far better than dirigible. Drop it into the atmosphere and use rockets at some point to stop decent and then quick gas up of the blimp before the rockets run out.

Then drop a heat resistant remote on to the surface for Guth or Mook to control from above. Mookie even has the idea. It is a one way trip.

Resupply might be a challenge.......................Trig

On Saturday, December 20, 2014 8:24:26 PM UTC+13, Posting into the ether wrote:
On Friday, December 19, 2014 10:21:00 AM UTC-8, J. Clarke wrote:
In article ,
says...

""The vast majority of people, when they hear the idea of going to Venus and
exploring, think of the surface, where it's hot enough to melt lead and the
pressure is the same as if you were almost a mile underneath the ocean," NASA's
Chris Jones told IEEE. "I think that not many people have gone and looked at
the relatively much more hospitable atmosphere and how you might tackle
operating there for a while."

However, at a height of around 50 km the atmosphere thins and cools to what one
would find here on Earth, which is exactly where NASA's High Altitude Venus
Operational Concept (HAVOC) would operate. The plan is to first launch a 31-
meter robotic airship to perform initial observations and ensure that the
secondary, manned mission would have a fair chance of success.

NASA would then follow up with a 30-day 2-manned mission aboard a 130-meter,
solar-powered airship with a small cabin slung beneath the helium-filled
dirigible. Then, perhaps, a year-long mission and, if everything goes well,
eventually a permanent floating outpost like a real life Cloud City. Though, as
you can see in the video above, just getting the necessary gear there will be
an enormous challenge and, for the manned missions, we'd have to send a pair of
spacecraft--the first with the airship, the latter with the crew. We can't even
get our Mars rovers to stop drawing dicks in the sand, and NASA really thinks
we're ready to start building floating towns and letting Billy Dee Williams
wear a cape again? Man I hope they're right because that's going to be awesome.
The capes, I mean."

See:

http://gizmodo.com/nasa-lets-explore...d-c-1672805652

Unless someone has figured out how to deliver something of a like or
similar nature to a fully-fueled Titan II to a dirigible in flight, this
would be a one way trip. Now let's see, that's on the order of 300
tons. The Hindenberg had a useful load of 5 tons. Not much that can go
wrong here, nosirree.

A Blimp might work far better than dirigible. Drop it into the atmosphere and use rockets at some point to stop decent and then quick gas up of the blimp before the rockets run out.

Then drop a heat resistant remote on to the surface for Guth or Mook to control from above. Mookie even has the idea. It is a one way trip.

Resupply might be a challenge.......................Trig

The ship returns after refuelling on Venus with propellants extracted from the Venusian atmosphere. There's 150 ppm H2O and larger amounts of H2SO4 which is a combination of H2O and SO3... there's plenty of sunlight. So, a balloon borne solar powered air processing unit would take H2O and H2SO4 out of Venus's atmosphere and make H2O and Oxygen - and there's 3.5% nitrogen - so that's a good buffer gas.

Aerocapture is described here;

https://spaceflightsystems.grc.nasa....t%20Sheet..pdf

http://adsabs.harvard.edu/abs/1979atfs.conf..195C

Aerocapture does not require rockets to slow down. Inflating a balloon in space and arriving at an appropriate altitude slows the balloon so that thermal and mechanical stresses are tolerable. This is the way to proceed.

A 124 meter diameter balloon that masses 50 metric tons carries 216 metric tons of oxygen inside it at 0.16 bar pressure. It also carries a 29 metric ton external tank like carrier structure that was part of the launch vehicle.

The oxygen is breathable and the interior gas is light enough so that it floats at an altitude of 62 km - where Venusian air density is 0.16 bar. Oxygen atmosphere is 0.218 kg/m3 at this pressure. CO2 atmosphere is 0.298 kg/m3 at this pressure. Enough to lift 79.8 tonnes which makes it neutrally buoyant.

As nitrogen oxygen and water are extracted from the Venusian atmosphere (Venus' atmosphere is 3.5% Nitrogen) pressure inside the envelope rises, as does density, and the balloon sinks - to a point where it is operating at 1 bar at 50 km altitude and has a far greater lifting capacity - enough to lift a fully ladened external tank! This joins with other tanks over time and shoots the payload back to Earth completing the mission.

This 295 tonne stage is blasted to Venus along a minimum energy transfer orbit.

The semi-major axis of the orbit of Venus is 0.723 AU. The semi-major axis of the orbit of Earth is 1.000 AU. The semi-major axis of an orbit that connects Venus Orbit and Earth Orbit is 0.8615 AU.

The vis-viva equation says

v = sqrt( 2/r - 1/a )

So,
v = sqrt(2/1-1/1) = 1.000 for Earth
v = sqrt(2/0.723-1/0.723) = 1.176 for Venus
v = sqrt(2/1- 1/0.8615) = 0.916 for transfer at Earth
v = sqrt(2/0.723-1/0.8615) = 1.267 for transfer at Venus

dV = 1.00 - 0.916 = 0.084 at Earth
dV = 1.267 -1.176 = 0.091 at Venus

Now 1 AU = 149,597,871 kilometers. The circumference of Earth's orbit is

2 * pi() * 149,597,871 = 939,951,145 km

There are 3.15569e7 seconds in one year. So dividing the circumference by the number of seconds in a year obtains 29.79 km/sec.

So, we convert these numbers to more conventional scales;

29.79 * 0.084 = 2.50 km/sec at Earth
29.79 * 0.091 = 2.71 km/sec at Venus

Now these are the hyperbolic excess velocities. The escape velocity of Earth is 11.19 km/sec. The escape velocity of Venus is 10.36 km/sec. This means that the speed that a vehicle sitting on Earth's surface must achieve to attain the hyperbolic excess velocity in orbit is

sqrt(11.19^2 + 2.50^2) = 11.47 km/sec - leaving Earth.
sqrt(10.36^2 + 2.71^2) = 10.71 km/sec - arriving at Venus.

So, eight external tanks - outfitted with aerospike engines at their base - fuelled by hydrogen and oxygen - with 7 clustered together and 1 atop the central element - all equipped with cross-feeding - is capable of putting over 700 tonnes into the Earth to Venus trajectory.

Two of the systems described above!

The payload arrives at Venus so that Venus is ahead of the vehicle, and approaching it at 2.71 km/sec. As it falls to the planet it picks up speed. It arranges to meet the atmosphere at the tangent line between the hyperbolic orbit and the surface all at an altitude of 92 km. That air density slows the spacecraft without damaging it.

http://www.daviddarling.info/images/aerocapture.jpg

A 124 meter diameter balloon that masses 295 tonnes including the oxygen inside.

Fd = 1/2 * rho * V^2 * A * Cd

Cd for a sphere is 0.5 and the diameter is 124 meters. We know mass is 295 tonnes. We also know we want to execute a 2 gee deceleration when we hit the Venusian atmosphere. We know our starting speed 10,710 meters/second. So, we can calculate rho - the density - with respect to time.

Fd = 2892932.25 = 346299769138.66 * rho -- rho = 0.000411 kg/m3

Pressure = 22.7 pascal = 0.000220 bar

http://selenianboondocks.com/2013/11...cket-floaties/

This occurs at 92 km altitude above the planet. So, first contact is made here.

Now at two gees and starting at 10,270 m/sec we require 523.7 seconds of braking. A little over eight minutes.

This requires a range of

D = 1/2 * a * t^2 = 0.5 * 2 * 9.80655 * 523.7^2 = 2,689.6 km.

This is 25.5 degrees around the circumference of the planet. The altitude starts at 92 km at 10.72 km/sec and ends at 62 km at 0 km/sec.

m/sec bar alt min

10270 0.0002205 92 0
9093 0.0002813 91 1
7916 0.0003711 90 2
6740 0.0005120 89 3
5563 0.0007515 88 4
4386 0.0012089 86 5
3209 0.0022580 83 6
2032 0.0056298 79 7
856 0.0317610 71 8
0 0.1600000 62 8.7

So, the orbit is calculated to come in at a slightly downward angle so that the vehicle is at the right altitude as it moves around Venus. The contact angle has a descent angle of 0.0986 degrees ( 5 minutes 55 seconds) after travelling 581 km in the first minute the vehicle slows to 9,093 m/sec falls 1 km and is dropping at 0.1123 degrees (6 minutes 44.4 seconds). After travelling another 510 km in the second minute it sinks another 1 km and is travelling at 7916 m/sec and is dropping at 0.1302 degrees (7 minutes 48.8 seconds). It travels another 440 km and drops another km in altitude in the third minute as it slows to 6740 m/sec. It is now sinking at 0.1553 degrees (9 minutes 19 seconds) from local horizontal. In the last 40 seconds of travel the angle steepens from 5 degrees descent to 30 degrees descent as the speed drops from 856 m/sec to zero in the last 18 km as it sinks 9 km..



range alt descent angle time
km dR dA deg min sec t-minutes
0
581 581 1 0 5 55.02 1
1091 510 1 0 6 44.44 2
1531 440 1 0 7 48.78 3
1900 369 1 0 9 18.98 4
2199 299 2 0 22 59.71 5
2427 228 3 0 45 14.09 6
2584 157 4 1 27 35.72 7
2671 87 8 5 16 33.71 8
2689 18 9 30 0 0.00 8.7