Category: Venus

Looking 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.
Continue reading “Venus Express Looks Right Down to the Surface”

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.
Continue reading “MESSENGER Heads Past Venus, Next Stop: 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.
Continue reading “Night Side Atmosphere on Venus”

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.
Continue reading “Science Updates from Venus Express”

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.
Continue reading “Double Vortex at Venus’ South Pole”

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

Venus Express main engine firing in space. Image credit: ESA Click to enlarge
One hundred days after beginning its cruise to Venus, ESA’s Venus Express spacecraft successfully tested its main engine for the first time in space.

The main engine test is a critical step in the mission. In fact, it is due to its powerful thrust that Venus Express will be able to ‘brake’ on arrival at Venus. The spacecraft must slow down in order to be captured in orbit around the planet.

The engine was fired during the night of 16/17 February, starting at 01:27 CET (00:27 UT) and the ‘burn’ lasted for about three seconds. Thanks to this engine burn, the spacecraft changed its velocity by almost three metres per second.

About one hour later, the data received from the spacecraft by the Venus Express ground control team (via ESA’s New Norcia antenna in Australia) revealed that the test was successful.

The engine performed as expected. The spacecraft reacted correctly to the push and was able to recover the control of its attitude and to correctly point its high-gain antenna back to Earth to communicate with ground control.

All data recorded during the burn will now be carefully analysed by Astrium (who built the spacecraft) and ESA’s engineers to study the performance of the engine in detail.

The next big milestone is the Venus Orbit Insertion manoeuvre on 11 April 2006, which will require the main engine firing sequence to operate for about 51 minutes in the opposite direction to the spacecraft motion. This braking will allow the spacecraft to counteract the pull of the Sun and Venus, and to start orbiting the planet.

Venus Express is currently at a distance of about 47 million kilometres from Earth.

Original Source: ESA Portal

Venus at the beach on Nov. 19th. Image credit: Pete Lawrence. Click to enlarge
It’s often said (by astronomers) that Venus is bright enough to cast shadows.

So where are they?

Few people have ever seen a Venus shadow. But they’re there, elusive and delicate?and, if you appreciate rare things, a thrill to witness.

Attention, thrill-seekers: Venus is reaching its peak brightness for 2005 and casting its very best shadows right now.

Amateur astronomer Pete Lawrence of Selsey, UK, photographed the elusive shadow of Venus just two weeks ago. It was a quest that began in the 1960s:

“When I was a young boy,” recalls Lawrence, “I read a book written by Sir Patrick Moore in which he mentioned the fact that there were only three bodies in the sky capable of casting a shadow on Earth. The sun and moon are pretty obvious, but it was the third that fascinated me — Venus.”

Forty years passed.

Then, “quite by chance a couple of months ago,” he continues, “I found myself in Sir Patrick’s home. The conversation turned to things that had never been photographed. He told me that there were few, if any, decent photographs of a shadow caused by the light from Venus. So the challenge was set.”

On Nov. 18th, Lawrence took his own young boys, Richard (age 14) and Douglas (12), to a beach near their home. “There was no ambient lighting, no moon, no manmade lights, only Venus and the stars. It was the perfect venue to make my attempt.” On that night, and again two nights later, they photographed shadows of their camera’s tripod, shadows of patterns cut from cardboard, and shadows of the boy’s hands?all by the light of Venus.

The shadows were very delicate, “the slightest movement destroyed their distinct sharpness. It is difficult,” he adds, “for a cold human being to stand still long enough for the amount of time needed to catch the faint Venusian shadow.”

Difficult, yes, but worth the effort, he says. After all, how many people have seen themselves silhouetted by the light of another planet?

If you’d like to try, this is the week. Your attempt must come before Dec. 3rd. After that, the crescent moon will join Venus in the evening sky, and any shadows you see then will be moon shadows.

Instructions: Find a dark site (very dark) with clear skies and no manmade lights. Be there at sunset. You’ll see Venus glaring in the southern sky: diagram. When the sky fades to black, turn your back on Venus (otherwise it will spoil your night vision). Hold your hand in front of a white screen?e.g., a piece of paper, a portable white board, a white T-shirt stretched over a rock?and let the shadow materialize.

Can’t see it? Venus shadows are elusive. “Young eyes help,” notes Lawrence, whose teenage sons saw the shadows more easily than he did.

Shadows or not, before you go home, be sure to look at Venus directly through binoculars or a small telescope. Like the moon, Venus has phases, and this week it is a lovely crescent. Aside: If Venus is at peak brightness, shouldn’t it be full? No. Venus is full when it is on the opposite side of the sun, fully illuminated yet far from Earth. Venus is much brighter now, as a crescent, because Earth and Venus are on the same side of the sun. Venus is nearby, big and bright.

Look at Venus or look away from it. Either way, it’s a great view.

Original Source: NASA News Release