manned missions to venus

[Ghostrider]

Now, landing on Venus...
It's not that it's impossible, it's just very hard and it implies a whole set of engineering problems vastly different from what we have with the Moon or Mars. First of all, we've got the fact that we're moving towards the inner Solar Sytem as opposed to the outer, so we're in for some nice speed on arrival. Nothing aerobraking can't handle but it may come back to haunt us when we're ready to get back to the Blue Marble.
Then, as opposed to the Moon with no atmosphere and Mars with a very thin one, Venus has an atmosphere and is not afraid at all to use it. Let's forget any fancy LMs here, what we'd need would be a cross between an airship and a bathyscaph. Pressure-wise, anything that can snap pretty pictures of the Titanic (minus Kate Winslet) should be able to withstand the pressure on the surface of Venus.
Now, heat, that's another matter. The surface of Venus makes Mordor look like St Moritz by comparison. How do you get rid of the heat? It should be possible to build a vessel able to withstand 500+ °C, but keeping a livable environment within is another matter...
As for stepping on the surface... Insulated shoes anyone?

 

[Graham2001]

Besides, if you did a flyby, what would you do next, land on it? What would you do once you got there?

The AAP mission mentioned in the OP, aside from being worked on by the NASSP crew is the one of the few NASA plan dealing solely with Venus as a target for manned exploration. NASA regarded Venus as a 'way-point' for it's manned Mars missions and never considered a manned-landing there.

All of the mission profiles I've seen with one exception have the spacecraft fly-by Venus releasing various probes into the Venusian atmosphere/near orbit environment before traveling on to another destination (either back to Earth or on to Mars).

The one exception is a 1967 study in which the spacecraft enters a highly elliptical orbit around Venus and spends 20 to 40 days studying the planet using drop probes and radar.

See: Manned Venus Orbiting Mission (1967)

 

[Hartmann]

Now, landing on Venus...
It's not that it's impossible, it's just very hard and it implies a whole set of engineering problems vastly different from what we have with the Moon or Mars. First of all, we've got the fact that we're moving towards the inner Solar Sytem as opposed to the outer, so we're in for some nice speed on arrival. Nothing aerobraking can't handle but it may come back to haunt us when we're ready to get back to the Blue Marble.
Then, as opposed to the Moon with no atmosphere and Mars with a very thin one, Venus has an atmosphere and is not afraid at all to use it. Let's forget any fancy LMs here, what we'd need would be a cross between an airship and a bathyscaph. Pressure-wise, anything that can snap pretty pictures of the Titanic (minus Kate Winslet) should be able to withstand the pressure on the surface of Venus.
Now, heat, that's another matter. The surface of Venus makes Mordor look like St Moritz by comparison. How do you get rid of the heat? It should be possible to build a vessel able to withstand 500+ °C, but keeping a livable environment within is another matter...
As for stepping on the surface... Insulated shoes anyone?

And what about take off and return ???

the enormous atmosphere pressure make very difficult for an engine have enough power for take off and in the case of a enough power, you could need a lot of fuel because the size of venus is the same of the earth .
The only option could be a blimp with a capsule like a bathiscaphe.

I think that a venus mission is a waste of money and resources that could be used in another and better missions. also they can do the same doing a flyby in a manned mission for mars or mercury, two very interesting places.

For example mercury is like a moon mission and could be done with a good shield or shade for the sun, analyse rocks, estudy the abundance of helium-3, geology and other cool things.:speakcool:

 

[Grawp]

Getting of Venus may be much more easier than you've supposed. Filling special baloons with proper inert gas would take the ship or return module to great altitude where it's thinner atmosphere and where it could slowly enagage thrusters a speed up, then at certain speed release the baloons (limit speed would depend on theirs shape and physical parameters of baloons) and continue turning ballistic trajectory to full orbit above the atmosphere.

But I really can't see any sense in manned mission to Venus.

sorry for my english

 

[Ghostrider]

And what about take off and return ???

the enormous atmosphere pressure make very difficult for an engine have enough power for take off and in the case of a enough power, you could need a lot of fuel because the size of venus is the same of the earth .
The only option could be a blimp with a capsule like a bathiscaphe.

Which is exactly what I suggested.
Anyway, Mercury would pose other problems: you would arrive with a good lot of speed and Mercury doesn't have that much of a gravity field. You're going to need BIG thrusters because there's no atmosphere to aerobrake in.

As for coming back... Well, some BIG thrusters again. And I guess you'd have to contend with some ol'sunshine.