Tag Archives: Venus

Two of five cameras on Japan’s Venus orbiter Akatsuki shut down

Japan has been forced to shut down operation on two of the five cameras on its Venus orbiter Akatsuki.

They think the problem has been caused by the additional five years required to get into Venus orbit when its main engine failed to fire during the first orbital attempt in 2010. During those five years the spacecraft was exposed to more radiation that expected, possibly damaging its equipment.

Akatsuki discovers a giant wave in Venus’ upper atmosphere

The Japanese Venus probe Akatsuki has discovered a giant persistent wave in the planet’s upper atmosphere that almost spans its entire face.

This week, researchers from Japan Aerospace Exploration Agency (JAXA) published infrared and ultraviolet images of Venus, taken by their Akatsuki orbiter between December 7 and 11, 2015, in Nature Geoscience. Akatsuki’s pictures reveal a curved region roughly 6000 miles long (Venus’ entire diameter is just around 7,500 miles) with a higher temperature than the surrounding atmosphere. How did the curved “smile” fight those high winds to remain in place for all four days of observation?

The answer may lie in a phenomenon very familiar to Earthlings. Gravity waves, not to be confused with gravitational waves, form when gravity pushes and pulls at the seam between two different materials. Waves on the ocean are perhaps the most obvious example—they exist where the sea meets the sky. But gravity waves also show up in the air, where wind flows over mountains to form waves that undulate upward through different layers of the atmosphere.

The mystery here is that scientists do not have a mountain chain that could have caused this giant Venusian wave. Moreover, it was there in 2015 but they haven’t seen it since.

Could Venus’ atmospheric dark streaks be life? Mission proposes to find out

A clever mission concept, proposed as a joint Russian/U.S. unmanned probe to Venus, would use a solar-powered unmanned aerial vehicle (UAV) to fly through the atmosphere for at least a year in order to try to find out the nature of the planet’s atmospheric mysterious dark streaks.

Descending hypersonically into the atmosphere after detaching from the orbiter, the UAV would be filled with hydrogen or helium gas, keeping it buoyant at a nominal floating altitude of 50 kilometers, allowing it to glide through the clouds while moving through the night-time hemisphere. Upon daylight, the solar-powered propellors would kick in and raise the craft’s altitude to around 60 kilometers.

Over the course of three to four days, the craft could move around the planet along the upper atmosphere’s ‘super-rotation,’ the strange phenomenon where the atmosphere seems to be uncoupled from the solid planet and rotates much faster. The UAV would therefore be able to explore the clouds at different altitudes, moving from air mass to air mass, from regions with UV absorbers to regions devoid of them, sampling and measuring the composition of the atmosphere.

The dark streaks, first photographed when Mariner 10 flew past on February 5, 1974 and took more than four thousand pictures, are made of a still unknown material in the upper clouds that absorbs ultraviolet light. The scientists of this mission concept propose that these dark streaks could even be Venusian life.

Finding life at high altitude in the atmosphere of a planet would make sense. After all, microbes have been found at similar heights in Earth’s atmosphere. The challenge for life on Venus is the planet’s extreme temperature. The surface, at 462º C (864º F), is hot enough to melt lead, and the surface pressure of 92 bar is the equivalent of being almost a kilometer under water.

However, in a region beginning around 50 kilometers in altitude and extending a dozen kilometers outward is a sweet spot where the temperature ranges between 30ºC and 70ºC (86ºF to 158ºF) and the pressure is similar to Earth’s surface. Life could potentially survive in this zone where the dark-streaking UV absorber is found.

Intriguingly, the sulfuric acid droplets within the clouds aren’t necessarily a show-stopper to life. Earlier Venera missions detected elongated particles in the lower cloud layer that are about a micron long, about the width of a small bacterium. These particles could be coated in ring-shaped polymers of eight sulphur atoms, called S8 molecules, which are known to exist in Venus’ clouds and which are impervious to the corrosive effects of sulfuric acid. Furthermore, S8 absorbs ultraviolet light, re-radiating it in visible wavelengths. If the particles are microbes, they could have coated themselves in S8, making them resistant to the corrosive effects of sulfuric acid. It has even been postulated that the S8 exists as a result of microbial activity.

Active volcano on Venus?

The uncertainty of science: A new analysis of past data from a variety of Venus orbiters suggests that at least one volcano is active there.

The review of old data from the Magellan and Venus Express orbiters suggests that some lava flows on the volcano’s slopes are fresh, though how fresh remains unknown. However, computer models and the detection of excess heat by Venus Express on the mountain’s eastern slopes adds weight to the theory that the volcano is spewing out lava.

Venus’s dark stripes remain unexplained

The uncertainty of science: A new analysis of past data from Venus suggests that the planet’s atmospheric sulfur cannot be causing the atmosphere’s dark stripes seen in the ultraviolet.

If we look at Venus in a normal optical telescope, we see only a dull yellowish-white sphere without any other distinguishing features. However, if we capture an image in the ultraviolet range, the picture changes drastically – dark and light areas appear on the disc, reflecting the dynamics of the atmosphere. “These areas mean that somewhere in the upper cloud layer there is a substance that is absorbing UV radiation. Over the past 30 years there have been a wide range of hypotheses as to what this substance could be. Many scientists believed that sulfur particles were responsible for the absorption. But now we will have to abandon this hypothesis,” says Krasnopolsky.

It appears that the new analysis puts the sulfur too low in the atmosphere.

Japanese Venus probe sends back first science data

In a triumph of engineering, the salvaged Japanese Venus probe Akatsuki has beamed back to Earth its first science data.

After an unplanned five-year detour, Japan’s Venus probe, Akatsuki, has come back to life with a bang. On 4–8 April, the Japan Aerospace Exploration Agency (JAXA) presented the first scientific results from the spacecraft since it was rescued from an errant orbit around the Sun and rerouted to circle Venus, four months ago. These include a detailed shot of streaked, acidic clouds and a mysterious moving ‘bow’ shape in the planet’s atmosphere.

Despite the probe’s tumble around the Solar System, its instruments are working “almost perfectly”, Akatsuki project manager Masato Nakamura, a planetary scientist at JAXA’s Institute of Space and Astronautical Science in Sagamihara, Japan, announced at the Inter­national Venus Conference in Oxford, UK. And if another small manoeuvre in two years’ time is successful, he said, the spacecraft might avoid Venus’s solar-power-draining shadow, and so be able to orbit the planet for five years, rather than the two it was initially assigned.

The timing is also good, since Akatsuki is now the only probe circling Venus, and will be for a number of years, until someone else approves, builds, and launches a mission.

Akatsuki to finally begin studying Venus

After a five year delay because its initial attempt to enter Venus orbit failed, the Japanese probe Akatsuki is finally about to begin science operations.

Its present orbit is less than ideal, passing 440,000km from the planet at its farthest point. That is roughly five times greater than initially planned and means the orbit time is now nine days. The change in orbit has affected the probe’s observation plan. Of its seven planned missions, Akatsuki will be able to complete only one: taking serial images of clouds. Unfortunately, the probe’s five cameras, each capturing images in different wavelengths, including infrared and ultraviolet, will not be able to provide the same resolution at this greater distance. Observing volcanic eruptions on the Venusian surface may also be difficult.

There is an upside to the situation, however. Takeshi Imamura, an associate professor at JAXA’s Institute of Space and Astronautical Science, says the longer orbital period means the probe will be able to collect longer continuous stretches of data.

Considering everything, it is magnificent that Akatsuki will be able to do any science at Venus at all.

Akatsuki’s Venus orbit confirmed

Venus in ultraviolet by Akatsuiki

Japanese engineers have confirmed that Akatsuki has entered orbit around Venus and can now begin science observations.

The image on the right was taken by the spacecraft’s ultraviolet camera, and clearly shows the as-yet unidentified dark material in Venus’s upper atmosphere. These dark streaks have been seen since the first Venus fly-by in the 1960s, but no observations have been able to determine what the material is that shows up as dark in ultraviolet light.

This success is a triumph for the engineers that operate Akatsuki. Kudos to them!

Success at last for Akatsuki

Five years after the Japanese Venus probe Akatsuki’s main engines failed while trying to put it into orbit, the spacecraft today fired its attitude thrusters and was successfully inserted into orbit.

This is a singular achievement by the Japanese engineers running the mission. They improvised a plan using the thrusters, which were designed to adjust the spacecraft orientation, not its course, and were able to get Akatsuki in an solar orbit that brought it back to Venus.

Japan’s Venus probe zeros in on Dec 7 arrival

A Japanese Venus research spacecraft, dubbed Akatsuki, has completed all its preliminary course corrections and is ready for a December 7 orbital insertion attempt, the second since the spacecraft’s main engine failed during the first attempt in 2010.

The space probe accomplished its last targeting maneuver Oct. 11 to aim for its Dec. 7 arrival at Venus, and all systems are go for the encounter, said Takeshi Imamura, Akatsuki’s project scientist at JAXA’s Institute of Space and Astronautical Science. Imamura said the Akatsuki spacecraft, named for the Japanese word for dawn, will zoom 541 kilometers, or 336 miles, above Venus for a 20-minute insertion burn using the probe’s secondary attitude control thrusters. Japanese ground controllers have programmed the probe to use the backup rocket jets after a faulty valve knocked out Akatsuki’s main engine during its first attempt to enter orbit around Venus in December 2010.

Four of the eight attitude control thrusters aboard Akatsuki will fire for 20 minutes and 33 seconds to slow the spacecraft down enough for Venus’ gravity to pull it into an egg-shaped orbit that skims above the planet’s cloud tops on the low end and ranges several hundred thousand miles in altitude at peak altitude. The reaction control thrusters, originally designed to help point the spacecraft, were not rated for such a hefty propulsive maneuver.

To make this second chance possible, they have spent the last five years improvising. First they dumped the fuel from the now-useless main engine to make the spacecraft lighter so that the attitude control thrusters could handle the maneuvers. Then they used those thrusters repeatedly to adjust the course to bring Akatsuki back to Venus after it zipped past in 2010.

If they succeed in getting it in a useful orbit on December 7, it will be real triumph for these Japanese engineers.

Venus probe about to rise from the dead

Five years after it failed to enter Venus orbit as planned, the Japanese probe Akatsuki is about to try again, in December.

The article provides an interesting and detailed explanation of what had gone wrong in 2010, and then describes the amazing things engineers have done to make this second attempt even possible. If they succeed it will be one of the most brilliant achievements in the history of space exploration.

Active lava flows found on Venus

volcanoes on Venus

Cool image time! Using archival data from Venus Express, scientists have identified several spots on Venus where it appears there are active lava flows.

Using a near-infrared channel of the spacecraft’s Venus Monitoring Camera (VMC) to map thermal emission from the surface through a transparent spectral window in the planet’s atmosphere, an international team of planetary scientists has spotted localised changes in surface brightness between images taken only a few days apart. “We have now seen several events where a spot on the surface suddenly gets much hotter, and then cools down again,” says Eugene Shalygin from the Max Planck Institute for Solar System Research (MPS) in Germany, and lead author of the paper reporting the results in Geophysical Research Letters this month. “These four ‘hotspots’ are located in what are known from radar imagery to be tectonic rift zones, but this is the first time we have detected that they are hot and changing in temperature from day to day. It is the most tantalising evidence yet for active volcanism.”

The hotspots are found along the Ganiki Chasma rift zone close to the volcanoes Ozza Mons and Maat Mons. Rift zones are results of fracturing of the surface, which is often associated with upwelling of magma below the crust. This process can bring hot material to the surface, where it may be released through fractures as a lava flow.

There have been hints of volcanic activity on Venus since Pioneer Venus Orbiter first circled the planet from 1978 to 1992. This appears to be the first solid evidence of it.

Five years later a second attempt to put a Japanese spacecraft into Venus orbit

If at first: After failing to place its Akatsuki spacecraft into orbit around Venus in 2010 because of a cracked engine nozzle, Japan has announced its plans for a new attempt later this year.

The attempt will be made on December 7. If successful, the spacecraft will begin studying Venus’s climate and atmosphere only a short time after the end of Europe’s very success Venus Express mission.

Venus Express mission ends

After eight years, the European Space Agency has officially ended the Venus Express mission.

After this month of ‘surfing’ in and out of the atmosphere at low altitudes, the lowest point of the orbit was raised again through a series of 15 small thruster burns, such that by 26 July it was back up to about 460 km, yielding an orbital period of just over 22 hours. The mission then continued in a reduced science phase, as the closest approach of the spacecraft to Venus steadily decreased again naturally under gravity.

Under the assumption that there was some propellant still remaining, a decision was taken to correct this natural decay with a new series of raising manoeuvres during 23–30 November, in an attempt to prolong the mission into 2015. However, full contact with Venus Express was lost on 28 November. Since then the telemetry and telecommand links had been partially re-established, but they were very unstable and only limited information could be retrieved.

The agency has decided that further attempts to contact the spacecraft would essentially be a wasted effort, and has closed the books on this very successful mission. The spacecraft itself will soon burn up in Venus’s atmosphere when its orbit decays.

Venus Express gone?

Engineers have been struggling to maintain contact with Venus Express, and have only been able to establish contact for intermittent periods.

Europe’s Venus Express was launched in November 2005 and got to the second planet from the Sun in April 2006, on what was originally a two-year mission. Since then it has sent data streaming back from its polar orbit.

But the probe’s days are numbered, and last month the flight control team at the European Space Operations Centre (ESOC) at Darmstadt, Germany, reported loss of contact with it. According to ESA’s Venus Express blog, it is possible that the remaining fuel on board the spacecraft was exhausted during recent manoeuvres and that the spacecraft is no longer in a stable attitude (the spacecraft’s high-gain antenna must be kept pointed toward Earth to ensure reliable radio contact).

They have been able to get bits of telemetry from the craft, but since its fuel supply is almost gone the possibility of keeping it operating much longer is limited.

Snowcaps of metal on Venus?

A new look at old data of Venus has added weight to the theory that the planet’s higher elevations are coated with a frost of heavy metals.

The research not only confirmed a radar brightening at higher altitudes, thus suggesting a frost coating of some kind, it also showed many dark spots whose cause remains completely unknown. As the article notes,

Years ago it was proposed that some sort of ferro-electric compound might be the cause of the brightening and the dark spots, but so far no specific compound has been identified which does the trick. Then again, with the surface of Venus being at almost 900 °F (500 °C) under more than 90 times the air pressure of Earth’s atmosphere at sea level, with occasional showers of acid, it’s not easy to test the properties of materials under Venusian conditions. “No one knows what explains the sudden darkness,” said Harrington, who will be presenting the work at the meeting of the Geological Society of America in Vancouver, B.C., on Monday, Oct. 20.

Venus Express is alive

After diving into Venus’s atmosphere on an aerobraking test that could have destroyed the spacecraft, the European probe Venus Express has now successfully used its last bits of fuel to raise its orbit back to research height.

Its present orbit will probably decay sometime in December, when the spacecraft will burn up in the atmosphere. However, the scientists running the mission though that was likely to happen during the aerobraking maneuver. Instead, Venus Express is giving them about another half year of research.

Venus Express is coming up for less air

After spending a month dropping down deep into Venus’s atmosphere, engineers are now raising Venus Express’s orbit.

Thus routine science operations concluded on 15 May, and the spacecraft’s altitude was allowed to drop naturally from the effect of gravity, culminating in a month ‘surfing’ between 131 km and 135 km above the surface. Additional small thruster burns were used to drop the spacecraft to lower altitudes, reaching 130.2 km earlier this week. Tomorrow, it is expected to dip to 129.1 km.

After eight years orbiting Venus, the mission is finally ending. They will use the spacecraft’s thrusters to lift it back up to almost 500 kilometers, where they will then allow its orbit to naturally decay, eventually ending the mission when it burns up in the atmosphere. There is also the chance they will run out of fuel during these last burns, ending the mission slightly sooner.

After concluding eight years of science observations in orbit around Venus, Venus Express is about to begin a series of atmospheric plunges to test the engineering of aerobraking at the extreme.

After concluding eight years of science observations in orbit around Venus, Venus Express is about to begin a series of atmospheric plunges to test the engineering of aerobraking at the extreme.

They plan to dive into Venus’s hellish atmosphere as low as 80 miles, where they hope not only to get data about this little studied region but to also learn more about the engineering of aerobraking. The article also gives a nice overview of the knowledge that Venus Express gathered in the past eight years.

Scientists think they have detected active volcanoes on Venus.

Scientists think they have detected active volcanoes on Venus.

We should hear more about this story in the next couple of days, after the scientists give their presentation at a science conference today. Note too that this result would only confirm other data, such as the fluctuating levels of sulfur in Venus’s atmosphere, that have suggested active volcanoes hidden under that planet’s thick cloud cover.

The geological history of Venus: What’s known, not known, and unknown.

The geological history of Venus: What’s known, not known, and unknown.

This is a very clearly written overview by James Head, one of the world’s preeminent planetary geologists, of what has been learned about the geology of Earth’s sister planet, the planet of a million volcanoes. Key quote:

Many features on Venus (folded mountain belts, rift zones, tesserae) were like Earth, but there were few signs of Earth-like plate tectonics, so that Venus seemed to have a single lithospheric plate that was losing heat conductively and advectively. But the cratering record presented a conundrum. First, the average age of the surface was <20% of the total age of the planet, and second, the average was not a combination of very old and very young surfaces, such as Earth’s continents and ocean basins. Third, the lack of variability in crater density, and of a spectrum of crater degradation, meant that all geological units might be about the same age. This implied that the observed surface of Venus must have been produced in the past hundreds of millions of years, possibly catastrophically, with very little volcanic or tectonic resurfacing since then! Suddenly, Venus was not like Earth, nor like the Moon, Mars, or Mercury.

Some scientists even believe that Venus was essentially resurfaced in a massive volcanic event about a half billion years ago. Others disagree. Meanwhile, the European probe Venus Express has gotten hints that volcanic activity is still going on.

As Head concludes, it has been 20 years since the last spacecraft arrived at Venus to do geological research. It is time to return.

A London university has digitized and placed online a collection of historic space images.

A London university has digitized and placed online a collection of historic space images.

I don’t think the press release’s claim that these images have never been online before is true for all the images. Nonetheless, the online availability especially of the Russian Venus images is very welcome.

After six years of study, Venus Express has found that during that time the super-rotating winds of Venus have actually increased in speed.

After six years of study, Venus Express has found that during that time the super-rotating winds of Venus have actually increased in speed.

When Venus Express arrived at the planet in 2006, average cloud-top wind speeds between latitudes 50º on either side of the equator were clocked at roughly 300 km/h [186 mph]. The results of two separate studies have revealed that these already remarkably rapid winds are becoming even faster, increasing to 400 km/h [250 mph] over the course of the mission.

The strange polar vortexes of Venus.

The strange polar vortexes of Venus.

The large-scale cyclone extends vertically in Venus’ atmosphere over more than 20 kilometers, through a region of highly turbulent, permanent clouds. However, the centers of rotation at two different altitude levels (42 and 62 km above the surface) are not aligned and both wander around the south pole of the planet with no established pattern at velocities of up to 55km/h. The study also finds that even when averaged cross-winds are roughly the same at both altitudes, there is still a strong vertical gradient, with winds increasing by as much as 3km/h for every kilometer of height and leading to possible atmospheric instabilities.

Changes in the levels of sulphur dioxide since Venus Express arrived in orbit around Venus in 2006 now suggest strongly that the spacecraft has detected volcanic activity on the planet.

Changes in the levels of sulphur dioxide (SO2) since Venus Express arrived in orbit around Venus in 2006 now suggest strongly that the spacecraft has detected volcanic activity on the planet.

The SPICAV data show that the concentration of SO2 above the main cloud deck increased slightly to about 1000 parts per billion by volume (ppbv) between 2006 and 2007, but then steadily decreased over the next five years, reaching only 100 ppbv by 2012. This is very reminiscent of a pattern observed by Pioneer Venus during the 1980s, the only other multi-year dataset of SO2 measurements.

One of best explanations for these changes is a volcanic eruption back in 2006, which would have inserted a great deal of SO2 into the upper atmosphere. Since then, ultraviolet radiation from the sun has steadily destroyed it.

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