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Interview with Dmitri Titov about the European Venus Express Mission

Aktualisiert: 25. März 2019

Interview with Dr. Dmitri Titov from the Max Planck Society (MPG)

1. Planet Venus was for a long time for the western space agencies not the primary target and always behind the Planet Mars, what is your opinion?

You are right. But this is for the planetary research worldwide.

For some reason after very successful Soviet Venera and US Pioneer Venus programmes in 70-80-s all the efforts were switched to Mars and Venus was forgotten for more than a decade.

The reason was that probably Space Agencies thought tht after about 25 missions to Venus nothing interesting was left to study.

However this was not the opinion in the science community which always considered Venus as highly attractive target with a great number of fundamental unsolved problems.

This is proved by the fact that in US almost every round of Discovery Programme had one or several Venus missions proposed.

The other reason for that Venus was in a shadow is that conditions on Mars were more Earth-like, Mars was always considered as a potential target for a manned flight, and possible harbor of extraterrestial life.

2. You have worked on several Soviet Venus mission including the very succesful Venera missions, what was your feeling as you received the first pictures from the surface.

Yes, end of 70-s and 80-s, when I came to the Space Research Institute in Moscow as a PhD student, were fascinating years for the Soviet Venera programme.

Soviet Union launched two spacecraft almost every ballistic window (~17 months) with gradually increasing complexity of the payload.

The first temperature measurements, first spectra, first panoramas - every step brought a lot of surprises. That was indeed the era of discoveries.

3. Venus is also known as Earth’s sister planet, but both planets are very different today, what is your opinion? Do you think that the Venus once had similar conditions like earth with liquid water? On Planet Mars the most scientists are sure that these conditions were available for a short period.

In major parameters (like distance to the Sun, size, initial composition) Earth and Venus can be considered as twins. They started from relatively similar conditions and then their evolutionary pathes strongly diverged. Scientists now call this situation : "twins separated at birth". The main turning point was that it seems Venus could not keep liquid water on its surface due to so-called "runaway greenhouse" and Earth could. Earth oceans played an important role in absorbing CO2 from the atmosphere and putting it in sediment rocks that strongly reduced greenhouse effect (which is on Venus produced mainly by CO2 atmosphere). We can say that we on Earth build our houses from what is atmosphere on Venus ;}.

Probably Venus once had moderate conditions and had water on its surface but it could not last for a long time.

As you see comparison of Earth and Venus poses very important question: where is habitability zone in the Solar System?

One of the problems on Venus is that its surface is very young: ~700 Million years ago global volcanic catastrophe covered the surface with young lavas. So we even do not have any record (as river beds on Mars for instance) to judge about early climate on Venus. The records are buried under kilometers thick llavas.

4. In the year 2002 scientist from the University of Texas (Link) published the speculative theorie, that in the atmosphere of the planet could exists microbes, what do you think about this?

I looked at the web site. It tells about the conclusions of a special planetary protection group about possible contamination of Venus by entry probes or at sample return. There are a lot of speculations concerning that the venusian life, if ever existed, could find a relatively comfortable niche in the clouds (although temperatures and pressure are quite moderate, the chemical environment is very hostile * cloud droplets consist of 75% sulfuric acid). Well, interesting possibility but to my opinion it should be put in the section entitled "'Why not?".

5. The conclusion after the primary mission of Venus Express is positive, do you expected that before? What comes after Venus Express? Is there any similar European mission or have other projects priority? Is it possible that one day a rover stay on the surface of Venus?

All scientists involved in Venus Express are very happy to collect fantastically rich harvest of data. Space mission is always a risky adventure. I think Europe * a beginner in this business - is doing quite well having successful Mars and Venus Express. (Just compare to how many missions were lost in the beginning of space era by Soviets and Americans!) With Venus Express almost everything is going like was planned. One can call it luck, but it is rather many days of hard and enthusiastic work of hundreds of people at ESA, Astrium and research institutes who built the spacecraft and the payload.

Unfortunately there is a bit of sadness in the honey: one experiment-Planetary Fourier Spectrometer- cannot open its window to see the planet. The instrument is working perfectly but sees only internal calibration lamps. We try to recover science goals by using other instruments.

We are waiting for the Japanese Venus Climate Orbiter (or Planet-C) to arrive at Venus in the end of 2010. This mission has 5 cameras onboard and the spacecraft will be inserted in equatorial orbit, so together with VEX (which is in polar orbit) they will make excellent complimentary observations of atmospheric dynamics.

VESPER * a Discovery proposal of an orbiter to Venus with powerful microwave payload is waiting for decision at NASA. We expect the decision to come by the end of 2007.

These 3 missions (VEX, Planet-C and VESPER) are remote sensing missions that results in some limitations. They should be followed by in-situ investigations. Rovers and long-living landers are probably in rather distant future since we still do not have electronics working at such temperatures. But balloons flying in the clouds and short living landers (a'la Venera) are quite possible already now. There are well developed technologically proposals from the science community in Europe, USA and Russia. Now it is up to Space Agencies to select and implement them.

6. The USA will return manned to the moon and also the Chinese have similar plans, what do you think about the future in space exploration in the next 50 years?

In space I would distinguish between two fields: 1. scientific research; and 2. exploration.

The space (or better planetary) science is driven mainly by scientific reasons and goals. The coming several decades should bring new missions and results in the study of the outer planets, their satellites and small bodies (comets and asteroids). Venus and Mars will be studied intensively: more sophisticated long living mobile laboratories will be sent to Mars and Venus will be visited by balloons and descent probes. Discoveries and detailed studies of the extra-solar planets are awaited.

The exploration field is to my mind mainly driven by political arguments. It seems that now we are on the eve of the second round of space race. The first one was in 60-s when two space powers were competing for the first step on the moon. Probably in the near future the young space powers (China first of all) will make a manned flight to the Moon a national priority. Their motivation is clear. On the contrary, the arguments for USA to go to the Moon again seem rather doubtful to me.

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