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Podcast: Larry Esposito and Venus Express

Artist illustration of Venus Express. Image credit: ESA. Click to enlarge.
Listen to the interview: Larry Esposito and Venus Express (5.5 MB)

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Fraser: First, congratulations on today’s launch.

Larry Esposito: The launch went very well. Venus Express spacecraft is now on its way to Venus.

Fraser: And how is the spacecraft?

Esposito: Everything appears to be perfectly healthy. Everything is as expected at the moment.

Fraser: That’s good. It almost seems unusual. A lot of the time there are glitches, so it’s great to hear that everything’s going so well.

Esposito: The spacecraft did take a two-week delay while they looked for possible contamination, but it had not been contaminated so everything is looking very good at the moment.

Fraser: Okay, so let’s fast forward a few months into April when Venus Express does arrive at Venus. What’s going to happen?

Esposito: The spacecraft arrives at Venus on the 11th of April, 2006, and then goes into orbit around Venus by firing some retro-rockets. After that, there’s a period of commissioning the spacecraft, where the instruments and all the systems aboard are checked out. And then Venus Express begins observing the atmosphere, the clouds, and the surface of Venus.

Fraser: What scientific instruments does Venus Express bring to Venus that haven’t been there before?

Esposito: Venus Express is carrying telescopes and cameras that are similar to those that have previously been in orbit around Venus. But it benefits from better technology and also from a capability to look through the atmosphere at a very specific wavelength where the atmosphere is more transparent and it’s possible to actually see the surface of Venus.

Fraser: What kinds of mysteries are you hoping to reveal with this mission?

Esposito: Venus is considered by many to be a twin of Earth. It’s almost the same size, it was formed at the same time around the Sun, it receives about the same amount of light from the Sun as the Earth. And the question that we have, probably the most basic question, is giving that they’re nearly twin planets, what went wrong on Venus? Venus, if anything, is an evil twin of the Earth. Its surface temperature is as hot as the inside of a self-cleaning oven. It has pressure of 100 times that of the atmospheric pressure of the surface of the Earth. The atmosphere is filled with sulphurous gasses and completely shrouded by clouds. So Venus, in some way has gone terribly wrong compared to the Earth. The mystery may be how global warming on Venus got out of control and put it into the state it’s currently in. And on the Earth, where we’re experimenting with our own atmosphere by releasing greenhouse gasses, though the burning of oil and coal, the question is: could the Earth go along the same path? So one of the basic mysteries is, how did Venus go wrong, and how can we avoid that on the Earth? I’d like to say it’s much better to do a theoretical study and experiments on Venus instead of doing the experiments on Earth through global warming, where the result may be very poo for the future of life on the Earth. So the biggest mystery has to do with the history of Venus and the potential for the Earth to follow that path.

Fraser: What kind of evidence would you be looking for to tell you what might have sent Venus down that path?

Esposito: Measurements that Venus Express will be taking are measurements of the composition of Venus’ atmosphere, the motions of the atmosphere, and measurements of how sunlight absorbs into the atmosphere of Venus. In addition to that, the spacecraft will be looking through the atmosphere and measuring the temperature of the surface. So it could well be that the history of Venus’ climate is very much related to geological activity, volcanic activity, on the surface. So we’ll be looking for signs of active volcanoes, we’ll be looking for volcanic gasses in the atmosphere, we’ll be looking for absorbing compounds that could capture some of the Sun’s radiation, that warm Venus’ atmosphere. And in addition to that, that spacecraft has an objective to look for the possibility of any connection the environment has to the possibility of past or present life on Venus.

Fraser: And what kinds of additional challenges went in to build the spacecraft to let it be able to survive the environment there. Isn’t it very much related to the Mars Express spacecraft?

Esposito: Right, and luckily for the Europeans, who have built and launched and are operating the spacecraft, it doesn’t have to enter the Venus environment. It simply goes into orbit around Venus the way the Mars Express mission is in orbit around Mars. And it’s essentially a copy of that mission. So the spacecraft remotely senses through cameras and telescopes and spectrometers the Venus environment but it doesn’t actually enter into it. That would be a much more difficult, much more expensive, technical task and that’s not the mission of Venus Express.

Fraser: I know it’s been done briefly in the past by the Russians. Are there any plans in the near or far future to try and get back down onto the surface?

Esposito: The US National Research Council has issued a report about new frontiers in exploring the Solar System, and one of their top four missions is a mission that would land on the surface of Venus and investigate that surface. And in response to that recommendation by the National Research Council, I led a team that developed a proposal for a mission that would land on the surface of Venus and drill into sample the surface and atmosphere. But unfortunately NASA has declined to fly that mission at the present time. It’s possible that we’ll propose something like that in the future. But right now, the techincal and financial challenges were too large for NASA to take on at the moment.

Fraser: And one of the questions I always want to ask the people working on these missions is that a lot of the time there are pretty big surprises; some of them are expected, and some you have a hope that you’re going to find something. What would be one of the big surprises that you think might be waiting for us at Venus?

Esposito: Of course you’re right, there are always many surprises ahead, even after all the missions that have flown to Venus. And I’d particularly like to see some confirmation of volcanic activity. Another possible surprise is the identification of ultraviolet absorbers and the possibility that they might be connected with life forms in the Venus atmosphere. As the other surprises, it’s hard to predict. Maybe we’ll just be surprised because this Venus mission is more capable than any that have been sent into orbit Venus, and just maybe be able to find out things that we have no expectation. Anything that was related to volcanic eruptions and life would be very interesting on Venus.

Fraser: I’d read that recently that something is blocking ultraviolet light in the high atmosphere and that could actually create an ecosystem that life could survive in?

Esposito: We know definitely that there are ultraviolet absorbers in the clouds, but we haven’t been able to identify them, yet. The fact that they absorb sunlight could be the start of some biological ecosystem in the Venus clouds. That’s pretty speculative at the moment, but very interesting to think of those possibilities. And Venus express will be observing in ways that could shed more light on that question, on Venus life at the present time.

Fraser: I know Mars Express has equipment that can detect methane in the Martian atmosphere. Would there be something similar…

Esposito: The same experiment is flying on Venus express – the Planetary Fourier Spectrometer – on Venus Express, and it could also detect methane and other chemicals in Venus’ atmosphere. But methane is very unlikely at Venus because of the high temperatures and the strong sunlight there.

Fraser: So the sunlight would be destroying the methane quickly on Venus as it would be on Mars. If there was methane, it would be…

Esposito: Yes, sunlight and heat are very disruptive to methane.

Fraser: So the spacecraft is equipped to detect it, but it would be quite surprising if it was there.

Esposito: That’s right.

About 

Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay.

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