Flyby Images of Venus from MESSENGER

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NASA’s MESSENGER spacecraft made its second flyby of Venus earlier in June, and scientists have now released the images. The photographs attached to this story actually show the pictures the spacecraft captured as it was traveling away from Venus, on its way to an encounter with Mercury in the future.

MESSENGER has a suite of instruments designed to map out the details of Mercury’s surface; unfortunately, Venus is obscured by thick clouds, so it wasn’t able to see down to map out the terrain and minerals. That task will have to wait until it reaches Mercury. However, it did get an opportunity to observe the cloudy planet at the same time ESA’s Venus Express was observing. Scientists will be able to compare images, combine data, and calibrate scientific instruments from this double view.

The spacecraft has now past Venus for the last time; all of its future planetary encounters will be with Mercury. It will make three flybys of the closest planet to the Sun before going into orbit in 2011.

Original Source: NASA/JPL/JHUAPL News Release

Two Spacecraft will Image Venus Together

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NASA’s MESSENGER and ESA’s Venus Express spacecraft are going to be at Venus together on June 6, giving scientists an opportunity to see our “evil” twin planet from two vantage points.

Of course, Venus Express has been orbiting its namesake planet since April 11, 2006, but Messenger is passing through, enroute to Mercury. And that’s not all. Several ground-based observatories will be joining in on the party as well, taking images and gathering data during the MESSENGER flyby.

During its closest approach, MESSENGER will pass just 337 kilometres (210 miles) above the surface of Venus. And during this time, Venus Express will be behind Venus, but will be able to view many of the same regions imaged by MESSENGER. Scientists will then be able to compare the data gathered by the two spacecraft.

After 30 hours of observations, MESSENGER will be finished with Venus, and focused again on its final target. It’ll finally reach Mercury in March, 2011.

Original Source: ESA News Release

Venus Express Looks Right Down to the Surface

Regions of Venus mapped by VIRTIS. Image credit: ESALooking down through Venus’ thick cloud cover isn’t easy work. That’s why ESA’s Venus Express was equipped with the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument. It allows the spacecraft to see infrared spectral windows that appear in the planet’s atmosphere. These allow heat radiated by the hot rocks on Venus’ surface to reach space, and Venus Express’ instruments. The VIRTIS team hopes to eventually use this technique to see mysterious hot spots on the surface of Venus that could be active volcanoes.
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What Venus and Saturn Have in Common

Astronomers have known about a strange vortex at the south pole of Venus since the 1970s, when it was discovered by NASA’s Pioneer Venus spacecraft. And recently, the Cassini spacecraft imaged a similar vortex at Saturn’s southern pole. The two vortices are caused when an area of low pressure sits at the rotation pole of a planet. This causes air to spiral down from higher in the atmosphere, like water going down a drain. Any planet with an atmosphere, even the Earth, can form a vortex like this. Venus’ vortex is unusual because it has two eyes that rotate around each other.
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Back to Venus with Vesper

While Venus is the same size as our Earth, its hellish surface environment makes it inhospitable to life. What went wrong with Venus? Now NASA is working on a new spacecraft called Vesper that could visit Venus, and try to get to the bottom of the question. Once launched, Vesper could begin orbiting Venus in March 2015. It would have a suite of instruments that would analyze the planet’s atmosphere over the course of two years.
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MESSENGER Heads Past Venus, Next Stop: Venus

NASA’s MESSENGER made its closest approach to Venus today, coming within 2,990 kilometers (1,860 miles) of its surface. The spacecraft used this close encounter with Venus’ gravity well to alter its trajectory as it travels towards its final destination: Mercury. This won’t be its final encounter with our twin planet, though. MESSENGER will meet up with Venus again in June 2007. It’ll finally make its first encounter with Mercury in January 2008, but won’t be in a final orbit until 2011.
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Night Side Atmosphere on Venus

Mars may get most of the news, but don’t forget there’s a spacecraft orbiting Venus too. New images released from ESA’s Venus Express spacecraft show new details about our twin planet’s atmosphere. These night-side infrared images reveal thermal radiation emanating from beneath the planet’s thick obscuring cloud deck. The clouds themselves are stretched out because of high-speed winds in the atmosphere.
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Science Updates from Venus Express

ESA’s Venus Express spacecraft concluded its in-orbit commissioning phase last week, and the agency has declared it ready to enter the operational phase of its science mission. All of its instruments are performing well, except for the Planetary Fourier Spectrometer (PFS), which has a malfunction. The mirror used to target the instrument is locked in the “close” position, preventing the instrument from being able to gather data.
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Double Vortex at Venus’ South Pole

New images from ESA’s Venus Express confirm that the cloud-covered planet has twin atmospheric vortexes at its southern pole. Previous missions to Venus saw stormy southern skies, but these images map out the shape of the double vortex in detail. High velocity winds take only 4 days to spin around Venus. This “super rotation” combines with the natural recycling of hot air to create this vortex structure. Scientists aren’t exactly sure why it’s creating a double vortex, though.
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Venus Express is in the Final Orbit

Artist’s view of Venus Express at Venus. Image credit: ESA. Click to enlarge
After a month of maneuvering, ESA’s Venus Express has reached its final science orbit. The spacecraft made its final maneuver on May 6, firings its engines to tighten its orbit to one that ranges between 66,000 and 250 km (41,000 and 155 miles) above the planet. Its scientific instruments will now be turned on and tested over the course of May. This will make the spacecraft ready for its science phase, due to begin on June 4, 2006.

Less than one month after insertion into orbit, and after sixteen loops around the planet Venus, ESA’s Venus Express spacecraft has reached its final operational orbit on 7 May 2006.

Already at 21:49 CEST on 6th May, when the spacecraft communicated to Earth through ESA’s ground station at New Norcia (Australia), the Venus Express ground control team at ESA’s European Spacecraft Operations Centre (ESOC) in Darmstadt (Germany) received advanced confirmation that final orbit was to be successfully achieved about 18 hours later.

Launched on 9 November 2005, Venus Express arrived to destination on 11 April 2006, after a five-month interplanetary journey to the inner solar system. The initial orbit – or ‘capture orbit’ – was an ellipse ranging from 330 000 kilometres at its furthest point from Venus surface (apocentre) to less than 400 kilometres at its closest (pericentre).

As of the 9-day capture orbit, Venus Express had to perform a series of further manoeuvres to gradually reduce the apocentre and the pericentre altitudes over the planet. This was achieved by means of the spacecraft main engine – which had to be fired twice during this period (on 20 and 23 April 2006) – and through the banks of Venus Express’ thrusters – ignited five times (on 15, 26 and 30 April, 3 and 6 May 2006).

“Firing at apocentre allows the spacecraft to control the altitude of the next pericentre, while firing at the pericentre controls the altitude of the following apocentre,” says Andrea Accomazzo, Spacecraft Operations Manager at ESOC. “It is through this series of operations that we reached the final orbit last Sunday, about one orbital revolution after the last ‘pericentre change manoeuvre’ on Saturday 6 May”.

Venus Express entered its target orbit at apocentre on 7 May 2006 at 15:31 (CEST), when the spacecraft was at 151 million kilometres from Earth. Now the spacecraft is running on an ellipse substantially closer to the planet than during the initial orbit. The orbit now ranges between 66 000 and 250 kilometres over the Venus and it is polar. The pericentre is located almost above the North pole (80º North latitude), and it takes 24 hours for the spacecraft to travel around the planet.

“This is the orbit designed to perform the best possible observations of Venus, given the scientific objectives of the mission. These include global observations of the Venusian atmosphere, of the surface characteristics and of the interaction of the planetary environment with the solar wind,” says Hakan Svedhem, Venus Express Project Scientist. “It allows detailed high resolution observations near pericentre and the North Pole, and it lets us study the very little explored region around the South Pole for long durations at a medium scale,” he concluded.

Until beginning of June, Venus Express will continue its ‘orbit commissioning phase’, started on 22 April this year. “The spacecraft instruments are now being switched on one by one for detailed checking, which we will continue until mid May. Then we will operate them all together or in groups” said Don McCoy, Venus Express Project Manager. “This allows simultaneous observations of phenomena to be tested, to be ready when Venus Express’ nominal science phase begins on 4 June 2006,” he concluded.

Original Source: ESA Portal