Draft NASA plans for a human mission to Venus have spread virally though the mainstream media, and caused journalists in distant lands to contact this analyst for clarification. It's no wonder. NASA spits out plans for some grand scheme every few months.

Nothing much seems to happen. The ideas get steadily weirder. Nobody knows what NASA is doing, and the spaceflight community is becoming increasingly concerned that the agency itself does not know what it is doing.

Let's just recap the latest plan. The proposed mission calls for astronauts to fly to Venus and spend time exploring the planet from the comfort of an airship stationed in the cool upper layers of the Venusian atmosphere. In theory, this could be done. But why?

The astronauts will not land on the surface of the planet. That's understandable. With surface temperatures hot enough to melt lead, and huge atmospheric pressures, even hardened robotic probes struggle to work for more than an hour. So, what's the point of having a few merry travellers hanging about in the air?

In theory, they could study the atmosphere around them. But so can robotic balloons and aircraft. They could also drop probes to the lower atmosphere and surface. So can robots. Are the astronauts just along for a slightly scientific joyride? The public won't accept this, and neither will the scientific community.

Let's contrast this with missions to the Moon and Mars. We can actually place astronauts on the surface and explore. The capabilities of humans over machines can be used to produce more scientific and exploratory returns than mere machines.

This analyst would love to see astronauts fly to the red planet and return to the Moon. One day, they will. But the whole idea of sending humans to Venus sounds crazy.

Our exploration of Mars holds the promise of eventually locating fossils or true Martian life. We can hold no such expectations for Venus.

The plan goes further. Eventually, we could build floating balloon colonies in the atmosphere of Venus. Such floating cities appear in science fiction. They will probably stay there. The idea of a short human mission to Venus is dubious. The proposal for a colony is even less credible.

NASA is an embattled government agency that's struggling for funding, political support and popular support. It needs to present a strong image of being rational, effective and inspiring.

It's a bitter irony that NASA seems to be getting increasingly befuddled in its public statements as well as its own internal planning. The agency could soon be its own worst enemy. There's too much hot air in the atmosphere of Venus, and there's an increasing amount coming from NASA itself.

Dr Morris Jones is an Australian space analyst who has written for spacedaily.com since 1999. Email morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email. Dr Jones will answer media inquiries.