Astronomy Cast Episode 259: Exploration of Venus

Mars gets all the attention, but you might be surprised to know how much Venus has been explored. From initial telescope observations and the early flyby missions, to the landers… yes landers and orbiters. We know quite a lot about Venus, but the planet sure didn’t give up its secrets easily.

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11 Replies to “Astronomy Cast Episode 259: Exploration of Venus”

      1. Because the audio hasn’t been edited and produced yet, but they will be soon. It takes longer to do the finished audio podcasts; these videos are the raw recordings, and a new way of sharing Astronomy Cast.

        Fixed the title here!

      2. Hey Nancy, where can one find the video for the Viking Orbiters? I’m subscribed to Astrospherevids and they don’t seem to have their listings up to date either. I can’t locate it on YouTube either. Guess I SHOULD be asking this to Emily, though. lol.

  1. The work required to pump heat is W = C?T. The heat capacity for CO_2 at constant pressure is 37J/(mole-K) and the heat difference is 600C. So for each mole of interior gas you need about 22200 joules of energy to cool it. This then 100kg of interior material that needs to be cooled it is clear that lots of energy has to generated. Even with a high R value for insulation I suspect the heat pump will have to operate in the 10 to 100Kw range. This will require an unusually large power source of some type.

    Heat pumps are not terribly when the temperature difference is large. The first law of thermodynamics tells us that the work in must equal the total heat

    dW = dQ_h – dQ_l

    for Q_h the high thermal energy Q_h = cT_h and Q_l the low thermal energy Q_l = CT_l. The efficiency of the heat pump is just the dW divided by dQ_h – dQ_l

    e = 1 – dW/d(Q_net) = 1 – (dQ_h – dQ_l)/(dQ_h + dQ_l) – 1 = 2Q_l/(Q_h~+~Q_l)

    This formula with Q_l = Q_h give e = 1 (100% efficiency) for the same temperature. For extreme temperature differences e becomes small. For Q_l ~ 300K and the temperature on Venus = 900K the maximum possible efficiency is 50%.

    So getting a rover to work on Venus is pretty ambitious — and expensive.


    1. Please Lcrowell. It’s hard to make sense of what you mean with the grammer and spelling mistakes.

      1. Thank you for sharing your viewpoint, in order to better understand your opinion can you please identify the “grammer and spelling mistakes” in the above comment? (Or should that be grammar?).

        LC’s comments are refreshing, well thought-out, challenging, and when cross-referenced proven factual. Having reviewed LC’s comments over time both here on UT and elsewhere on physics forums they border on inspirational genius and reflect the highest credit on the astronomical and mathematical community. When us mere mortals are as academically accredited as LC we can then and only then pass judgement.

      2. Since this involves Russian spacecraft I will say c?ac??a. Yes these comments are rather curious. I just ran this in MSW and spell check find nothing.


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