Author Topic: ESA - Venus Express updates  (Read 40993 times)

Offline Star One

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Re: ESA - Venus Express updates
« Reply #80 on: 09/17/2017 07:19 PM »
Venus’ mysterious night side revealed

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Scientists have used ESA’s Venus Express to characterise the wind and upper cloud patterns on the night side of Venus for the first time-with surprising results.

The study shows that atmosphere on Venus’ night side behaves very differently to that on the side of the planet facing the Sun (the ‘dayside’), exhibiting unexpected and previously-unseen cloud types, morphologies, and dynamics — some of which appear to be connected to features on the planet’s surface.

“This is the first time we’ve been able to characterise how the atmosphere circulates on the night side of Venus on a global scale,” says Javier Peralta of the Japan Aerospace Exploration Agency (JAXA), Japan, and lead author of the new study published in the journal Nature Astronomy. “While the atmospheric circulation on the planet’s dayside has been extensively explored, there was still much to discover about the night side. We found that the cloud patterns there are different to those on the dayside, and influenced by Venus’ topography.”

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Instead, the super-rotation seems to be more irregular and chaotic on the night side. Night side upper clouds form different shapes and morphologies than those found elsewhere-large, wavy, patchy, irregular, and filament-like patterns, many of which are unseen in dayside images — and are dominated by unmoving phenomena known as stationary waves.

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“This study challenges our current understanding of climate modeling and, specifically, the super-rotation, which is a key phenomenon seen at Venus,” says Håkan Svedhem, ESA Project Scientist for Venus Express. “Additionally, it demonstrates the power of combining data from multiple different sources-in this case, remote sensing and radio-science data from Venus Express’ VIRTIS and VeRa, complemented by ground-based observations from IRTF’s SpeX. This is a significant result for VIRTIS and for Venus Express, and is very important for our knowledge of Venus as a whole.”

https://astronomynow.com/2017/09/17/venus-mysterious-night-side-revealed/

Offline John-H

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Re: ESA - Venus Express updates
« Reply #81 on: 09/18/2017 01:32 AM »
Given the very long days and  nights on Venus, is the surface temperature significantly lower at night?  Low enough to make a probe viable?

John

Offline Nomadd

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Re: ESA - Venus Express updates
« Reply #82 on: 09/18/2017 02:54 AM »
Given the very long days and  nights on Venus, is the surface temperature significantly lower at night?  Low enough to make a probe viable?

John
Day and night temps are almost exactly the same. The Venusian atmosphere has a hell of an R factor.

Offline Sam Ho

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Re: ESA - Venus Express updates
« Reply #83 on: 09/18/2017 02:54 AM »
Given the very long days and  nights on Venus, is the surface temperature significantly lower at night?  Low enough to make a probe viable?

John
No. The extremely dense atmosphere makes the temperature pretty much uniform.

Offline Ben the Space Brit

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Re: ESA - Venus Express updates
« Reply #84 on: 09/20/2017 11:12 AM »
I don't think that you can even say Venus's surface has a 'night'. The light-refracting qualities of the middle atmosphere are so strong that daylight is scattered far onto the nominally 'night' side.
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Offline high road

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Re: ESA - Venus Express updates
« Reply #85 on: 09/22/2017 03:03 PM »
Given the very long days and  nights on Venus, is the surface temperature significantly lower at night?  Low enough to make a probe viable?

John

Why would you send a probe to the surface to study winds and weather paterns? Floating or flying probes equipped with radar can get you all the required data.

Offline redliox

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Re: ESA - Venus Express updates
« Reply #86 on: 09/23/2017 02:48 AM »
Given the very long days and  nights on Venus, is the surface temperature significantly lower at night?  Low enough to make a probe viable?

John

Why would you send a probe to the surface to study winds and weather paterns? Floating or flying probes equipped with radar can get you all the required data.


Floating is a good idea for atmospheric science, but you still need a lander vehicle for drilling, rock chemistry, and especially seismology.
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Offline woods170

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Re: ESA - Venus Express updates
« Reply #87 on: 09/23/2017 12:12 PM »
Given the very long days and  nights on Venus, is the surface temperature significantly lower at night?  Low enough to make a probe viable?

John

Why would you send a probe to the surface to study winds and weather paterns? Floating or flying probes equipped with radar can get you all the required data.


Floating is a good idea for atmospheric science, but you still need a lander vehicle for drilling, rock chemistry, and especially seismology.
With current state of technology a surface probe will survive for just a few days, at most. Probably shorter. Challenges: very high atmospheric pressure, extremely high surface- and atmospheric temperatures and highly corrosive atmosphere.
Had a lander for sustained surface operations (say longer than 2 days) been possible there already would have been sent one. That much I'm convinced of. But as the Venera's demonstrated the operational duration of surface probes on Venus is measured in minutes (hours at best), not days.
« Last Edit: 09/23/2017 12:14 PM by woods170 »

Offline JH

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Re: ESA - Venus Express updates
« Reply #88 on: 09/23/2017 05:01 PM »
There are many promising technologies that could allow for long term surface operations, but it is not yet possible. That is why the HOTTech program exists (see https://nspires.nasaprs.com/external/solicitations/summary.do?method=init&solId=%7B7C46C02B-4ADB-BDD8-CA52-714DE026F336%7D&path=init).

Offline high road

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Re: ESA - Venus Express updates
« Reply #89 on: 09/23/2017 06:06 PM »
Given the very long days and  nights on Venus, is the surface temperature significantly lower at night?  Low enough to make a probe viable?

John

Why would you send a probe to the surface to study winds and weather paterns? Floating or flying probes equipped with radar can get you all the required data.


Floating is a good idea for atmospheric science, but you still need a lander vehicle for drilling, rock chemistry, and especially seismology.
With current state of technology a surface probe will survive for just a few days, at most. Probably shorter. Challenges: very high atmospheric pressure, extremely high surface- and atmospheric temperatures and highly corrosive atmosphere.
Had a lander for sustained surface operations (say longer than 2 days) been possible there already would have been sent one. That much I'm convinced of. But as the Venera's demonstrated the operational duration of surface probes on Venus is measured in minutes (hours at best), not days.

The Venera and Vega probes all used basically the same lander design (the ones that had a lander, that is) that was developed before the Russians knew how punishing the Venusian surface environment was. Quite an achievement that they lasted as long as they did.

There are plenty of ideas to send low-tech floating probes (no propulsion, about a month of operational measurements), sets of expendable descent probes, propelled floating probes, planes, or in the more experimental class: low-altitude metallic bells, high temperature rovers etc. However, these ideas are in constant competition with all other highly interesting missions to other locations in need of funding, and more importantly, among themselves. Each specific 'cheaper' architecture would study completely different phenomena. There is so little data about Venus, too few people have made a career out of it and now lobby for it.

To Redilox: seismology would indeed be a problem for a floating probe. However, a low-altitude metallic bell can quite easily carry a chemcam, or even a drill to collect samples if it has enough propulsion or anchoring to remain stationary in Venusian wind, or should we say currents at such punishing pressures? In fact, it would be able to cover a lot more ground than Curiosity, and given propulsion, get to any interesting location.

That said, I never imagine any low altitude operations without a transport system that can lift the bell and lander to higher altitudes to cool down regularly, or supply them with coolant produced in the upper atmosphere.

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