Recent plans on human missions to Mars have sparked many discussions, one of which is about if we should colonize Venusian upper atmosphere with Zeppelin like floating ships and cities first.

NASA even has a mission developed - the High Altitude Venus Operational Concept (HAVOC) enter image description here

Why are people so fascinated about Mars and not about Venus at all?

Is there a new space race to Mars, and why don't some of the major players like Nasa, Cnsa, Roscosmos or Boeing consider Venus as a target for robotic exploration?

We have explored only 2 celestial bodies with robotic probes - The Moon and Mars. I don't talk about orbiters and impactors, but about real, driveable drones that are in Venus' atmosphere for months or years to come, and while we used rovers because of the lack of atmosphere on the Moon and to big extent on Mars, we can use all kinds of flying machines on Venus, so why wouldn't we send probes to Venus and explore it, like we have done with Mars?

P.S. These are somehow similar to this question :

Is there any plan to send balloon like probes to gas giants to explore interior of gas giants?

Have there been any official feasibility studies into descending balloons into outer planetary atmospheres?


4 Answers 4


When will we send? We already did.

Vega mission description

In 1985 and 1986 the Soviet Union sent two Vega probes to Venus. Both included a robotic balloon (usually called aerobots).

Vega balloon probe on display at the Udvar-Hazy Center of the Smithsonian Institution. Photo by Geoffrey A. Landis. Wikipedia

The two balloon aerobots were designed to float at 54 km from the surface, in the most active layer of the Venusian cloud system. The instrument pack had enough battery power for sixty hours of operation and measured temperature, pressure, wind speed and aerosol density. The balloon envelopes were surfaced with polytetrafluoroethylene to resist attack by the corrosive atmosphere. Both Vega-1 and Vega-2 balloons operated for more than 46 hrs from injection to the final transmission.

The balloons were spherical superpressure types with a diameter of 3.54 metres (11.6 ft) and filled with helium. A gondola assembly weighing 6.9 kilograms (15.2 pounds) and 1.3 meters (4.26 ft) long was connected to the balloon envelope by a tether 13 metres (42.6 ft) long. Total mass of the entire assembly was 21 kilograms (46 pounds). [...] The balloons were dropped onto the planet's darkside and deployed at an altitude of about 50 kilometres (31 mi). They then floated upward a few kilometres to their equilibrium altitude. At this altitude, pressure and temperature conditions of Venus are similar to those of Earth, though the planet's winds moved at hurricane velocity and the carbon dioxide atmosphere is laced with sulfuric acid, along with smaller concentrations of hydrochloric and hydrofluoric acid.

The balloons moved swiftly across the night side of the planet into the light side, where their batteries finally ran down and contact was lost. Tracking indicated that the motion of the balloons included a surprising vertical component, revealing vertical motions of air masses that had not been detected by earlier probe missions.


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    $\begingroup$ I feel you should make it clearer that this entire answer is copy-pasted from Wikipedia. Writing "(Wikipedia)" at the bottom really doesn't do that. And we're not trying to be an out-of-date Wikipedia mirror. $\endgroup$ Commented Jan 26, 2018 at 0:48
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    $\begingroup$ Feel free to edit my answer for making it clearer. Thank you. $\endgroup$
    – Ginasius
    Commented Jan 27, 2018 at 21:26

Why are people so fascinated about Mars and not about Venus at all?

The trivial answer - Mars is moderate place.

A human could easily get around with a spacesuit, and it is trivial for robots and equipment to exist on Mars.

Venus is a swirling hell.

The "atmosphere" is a sea of incredibly hot, ultra-boiling, 800+ °F sulfuric acid (!!!)

(Indeed, Venus is by far the most incredibly hot planet in our system!)

The very few things we have sent to Venus which landed there, were totally destroyed in an hour or so - the first ones in a few minutes.

The excellent Russian balloon-robots which stayed up high, with excellent '80s technology, (mentioned above) only lasted 2 days.

Venus is the solar system's hell.


[a few...] landers from the former Soviet Union have landed on Venus. They were only able to send us information for a short time because the extremely high temperature and pressure on the surface of Venus melted and crushed the landers...

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    $\begingroup$ You do understand that the question asked about floating probes in the (much milder) upper atmosphere of Venus, and not the surface level atmosphere which you describe? $\endgroup$ Commented Jan 25, 2018 at 18:52
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    $\begingroup$ That link isn't exactly accurate. Most of the landers were only able to send information for a limited time because the batteries ran out. They did not melt or get crushed before that happened. $\endgroup$
    – Skyler
    Commented Jan 25, 2018 at 20:38
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    $\begingroup$ I would also add that it's easier to heat things up in space than to cool them down. The sulfuric acid atmosphere, and pressure, are definitely bigger barriers (well pressure wouldn't be high up). But on mars/in-space you can heat up parts of your rover/spacecraft as you please, when you need, but getting rid of excess heat is more complex. $\endgroup$
    – spacetyper
    Commented Jan 25, 2018 at 21:14
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    $\begingroup$ To take @Skyler point even further, the record for longest lasting surface device on Venus is 127 minutes (2+ hours) by the Soviets in the 80's, and, if I recall correctly (and as Skyler suggested) it died due to battery depletion and not the harsh elements. It has been suggested that, with enough electrical power, even those older missions could have lasted a lot longer - not years like on Mars, but still much longer than they did. If designed specifically to combat the harsh conditions, it's likely possible to last indefinitely even on Venus. $\endgroup$
    – Aaron
    Commented Jan 25, 2018 at 21:43
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    $\begingroup$ Voted down. Yes it's harsh at the surface. The question isn't about the surface at all though. The question assumes that floating robots are easy to send (they're light after all) and to build (it's just a balloon after all .. no need to think about how to tackle different terrain, no necessary moving parts). And it assumes earth like conditions. A big issue are probably the hurricane like winds..? Doesn't answer the question though. $\endgroup$ Commented Jan 26, 2018 at 14:28

No, there is no space race to Mars.

The original space race was to orbit, for entirely military reasons. Sputnik was simply a demonstration of "we can drop a nuke anywhere we want, any time".

The second space race to the Moon was a publicity exercise. It served no military purpose, and it didn't serve any scientific purpose either. (Science builds off previous work. NASA deliberately destroyed all plans for the Atlas rockets, so that they could not be reproduced.) Primarily the reason was national pride (basically a willy-waving exercise with the USSR); and a strong secondary reason was a bread-and-circuses exercise in distraction from the war in Vietnam.

For Mars, we do not have either justification. A mission to Mars clearly isn't militarily useful. More importantly, the cost of the mission and the parlous state of the US and Russian economies mean that there isn't going to be any significant competition. China are actually in the strongest position nationally, since they have no political obstacles to redirecting funding at will. If there was an economic justification for going to Mars, then we could still get a space race from private investors trying to get a slice of the pie, but there is no economic reason.

Instead, what we have is a small collection of incredibly wealthy individuals funding private space research, with a fairly significant amount of government funding too. Inevitably someone will be first to get to Mars, but it isn't particularly a race, because all sides recognise that the important factor isn't getting there but surviving there. As private individuals without the artificial obstacles imposed by politics, this means we see a lot more collaboration. SpaceX may have the best rockets, but it's likely someone else will have the best hab, for example.

Venus certainly hasn't been missed out on exploration. Previous posts have pointed out how harsh the environment is - you'd need to really want to have a rover there, and currently there's no good reason to do that. On Mars we have a good reason for wanting a close-up view of the surface, because we hope someday to send people there. Venus is interesting from a pure curiosity point of view, but the cost-benefit appears low when orbiters have already done high-quality mapping and observation work, and there is no prospect of a human ever walking on the surface. The airship concept is interesting, but it fails to explain why it is necessary to put humans on the airship, when the purpose is only to do more observation work which can easily be done remotely.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – PearsonArtPhoto
    Commented Jan 28, 2018 at 0:37

Why are people so fascinated about Mars and not about Venus at all?

I've asked the same question, but I believe it comes down to that there is no sweet spot in the atmosphere of Venus where the pressure is good (0.1 - 1.0 atm), the winds aren't bad and the amount of sulfuric acid isn't thick.

Around 45-50 km above the surface, the pressure is around Earth sea-level, but the winds are 200+ kmph and thick with sulfuric acid! As you rise up, the winds get even stronger peaking between 60 and 70 km up with wind speeds over 350 kmph and still thick with sulfuric acid. The sulfuric acid starts to thin out around 80 km altitude because the pressure has dropped below 0.1 atm, but the wind speeds are still in excess of 150 kmph. It isn't until 100 km altitude (where the pressure is about 1% of Earth sea-level and about the same as the surface of Mars) that the wind speed drops below 50 kmph.

  • $\begingroup$ Are these wind speeds measured relative to the ground? It seems to me that high winds relative to the ground are not a problem if the wind is uniform. However, if there is turbulence and high wind gradients, then the balloon is going to get shredded. $\endgroup$ Commented Nov 14, 2021 at 21:03
  • $\begingroup$ @WaterMolecule: Hadn't thought of that, but even without the wind issue you still have the sulfuric acid issue until the air becomes so thin. Someday maybe we can engineer some kind of floating plant that loves uses sunlight to consume sulfuric acid and CO2! $\endgroup$
    – kjpires
    Commented Nov 19, 2021 at 2:10

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