ESA : Rosetta: 100 days to wake-up

Rosetta’s twelve-year journey in space

Access the video

http://spaceinvideos.esa.int/Videos/2013/10/Rosetta_s_twelve-year_journey_in_space

This animation tracks Rosetta’s journey through the Solar System, using gravity slingshots from Earth and Mars to reach its final destination: Comet 67P/Churyumov–Gerasimenko. Rosetta made three flybys of Earth, on 4 March 2005, 13 November 2007 and 13 November 2009, and one of Mars, on 25 February 2007. Rosetta has also visited two asteroids, taking extensive close-up images of 2867 Steins on 5 September 2008 and 21 Lutetia on 10 July 2010. Once the spacecraft is woken up from deep space hibernation on 20 January 2014, it will head for rendezvous with the comet in May. In November the Philae probe will be deployed to the comet surface. Rosetta will follow the comet to its closest distance to the Sun on 13 August 2015 and as it moves back towards the outer Solar System. The nominal mission end is December 2015.

Rosetta: 100 days to wake-up

11 October 2013

ESA’s comet-chasing mission Rosetta will wake up in 100 days’ time from deep-space hibernation to reach the destination it has been cruising towards for a decade.

Comets are the primitive building blocks of the Solar System and the likely source of much of Earth’s water, perhaps even delivering to Earth the ingredients that helped life evolve.

By studying the nature of a comet close up with an orbiter and lander, Rosetta will show us more about the role of comets in the evolution of the Solar System.

Rosetta was launched on 2 March 2004, and through a complex series of flybys – three times past Earth and once past Mars – set course to its destination: comet 67P/Churyumov–Gerasimenko. It also flew by and imaged two asteroids, Steins on 5 September 2008 and Lutetia on 10 July 2010.

In July 2011 Rosetta was put into deep-space hibernation for the coldest, most distant leg of the journey as it travelled some 800 million kilometres from the Sun, close to the orbit of Jupiter. The spacecraft was oriented so that its solar wings faced the Sun to receive as much sunlight as possible, and it was placed into a slow spin to maintain stability.

Now, as both the comet and the spacecraft are on the return journey back into the inner Solar System, the Rosetta team is preparing for the spacecraft to wake up.

Rosetta mission milestones 2014-2015

Rosetta’s internal alarm clock is set for 10:00 GMT on 20 January 2014.

Once it wakes up, Rosetta will first warm up its navigation instruments and then it must stop spinning to point its main antenna at Earth, to let the ground team know it is still alive.

“We don’t know exactly at what time Rosetta will make first contact with Earth, but we don’t expect it to be before about 17:45 GMT on the same day,” says Fred Jansen, ESA’s Rosetta mission manager.

“We are very excited to have this important milestone in sight, but we will be anxious to assess the health of the spacecraft after Rosetta has spent nearly 10 years in space.”

After wake-up, Rosetta will still be about 9 million km from the comet. As it moves closer, the 11 instruments on the orbiter and 10 on the lander will be turned on and checked.

In early May, Rosetta will be 2 million km from its target, and towards the end of May it will execute a major manoeuvre to line up for rendezvous with the comet in August.

The first images of a distant 67P/Churyumov–Gerasimenko are expected in May, which will dramatically improve calculations of the comet’s position and orbit.

Closer in, Rosetta will take thousands of images that will provide further details of the comet’s major landmarks, its rotation speed and spin axis orientation.

_{Continue reading below}

Rosetta’s Philae lander on comet nucleus

Rosetta will also make important measurements of the comet’s gravity, mass and shape, and will make an initial assessment of its gaseous, dust-laden atmosphere, or coma.

Rosetta will also probe the plasma environment and analyse how it interacts with the Sun’s outer atmosphere, the solar wind.

After extensive mapping of the comet’s surface during August and September, a landing site for the 100 kg Philae probe will be chosen. It will be the first time that landing on a comet has ever been attempted.

Given the almost negligible gravity of the comet’s 4 km-wide nucleus, Philae will ‘dock’ with it using ice screws and harpoons to stop it from rebounding back into space.

Philae will send back a panorama of its surroundings and very high-resolution pictures of the surface and will perform on-the-spot analysis of the composition of the ices and organic material. A drill will take samples from 20–30 cm below the surface, feeding them to the onboard laboratory for analysis.

“The focus of the mission then moves towards what we call the ‘escort’ phase, whereby Rosetta will stay alongside the comet as it moves closer to the Sun,” notes Fred.

The comet will reach its closest distance to the Sun on 13 August 2015 at about 185 million km, roughly between the orbits of Earth and Mars.

As the comet hurtles through the inner Solar System at around 100 000 km/h, the relative speed between orbiter and comet will remain equivalent to walking pace. During this ‘escort’ phase the orbiter will continue to analyse dust and gas samples while monitoring the ever-changing conditions on the surface as the comet warms up and its ices sublimate.

“This unique science period will reveal the dynamic evolution of the nucleus as never seen before, allowing us to build up a thorough description of all aspects of the comet, its local environment and revealing how it changes even on a daily basis,” says Matt Taylor, ESA’s Rosetta project scientist.

Rosetta will follow the comet throughout the remainder of 2015, as it heads away from the Sun and activity begins to subside.

“For the first time we will be able to analyse a comet over an extended period of time – it is not just a flyby. This will give us a unique insight into how a comet ‘works’ and ultimately help us to decipher the role of comets in the formation of the Solar System,” adds Matt.

For further information, please contact:

Markus Bauer

ESA Science and Robotic Exploration Communication Officer


Tel: +31 71 565 6799


Mob: +31 61 594 3 954


Email: markus.bauer@esa.int

Fred Jansen
ESA Rosetta mission manager
Email: fjansen@rssd.esa.int

Matt Taylor
ESA Rosetta project scientist
Email: matthew.taylor@esa.int

 

Europe's comet chaser

 

In November 1993, the International Rosetta Mission was approved as a Cornerstone Mission in ESA's Horizons 2000 Science Programme.

Since then, scientists and engineers from all over Europe and the United States have been combining their talents to build an orbite

Rosetta orbiting Comet 67P/Churyumov-Gerasimenko

r and a lander for this unique expedition to unravel the secrets of a mysterious 'mini' ice world – a comet.

Initially scheduled for January 2003, the launch of Rosetta had been postponed due to a failure of an Ariane rocket in December 2002. The adventure began March 2004, when a European Ariane 5 rocket lifted off from Kourou in French Guiana.

During a circuitous ten-year trek across the Solar System, Rosetta will cross the asteroid belt and travel into deep space, more than five times Earth’s distance from the Sun. Its destination will be a periodic comet known as Comet 67P/Churyumov-Gerasimenko.

The Rosetta orbiter will rendezvous with Comet 67P/Churyumov-Gerasimenko and remain in close proximity to the icy nucleus as it plunges towards the warmer inner reaches of the Sun’s domain. At the same time, a small lander will be released onto the surface of this mysterious cosmic iceberg.

More than a year will pass before the remarkable mission draws to a close in December 2015. By then, both the spacecraft and the comet will have circled the Sun and be on their way out of the inner Solar System.

Hide continue

Historic mission

The Rosetta mission will achieve many historic firsts.

• Rosetta will be the first spacecraft to orbit a comet’s nucleus.
• It will be the first spacecraft to fly alongside a comet as it heads towards the inner Solar System.
• Rosetta will be the first spacecraft to examine from close proximity how a frozen comet is transformed by the warmth of the Sun.
• Shortly after its arrival at Comet 67P/Churyumov-Gerasimenko, the Rosetta orbiter will despatch a robotic lander for the first controlled touchdown on a comet nucleus.
• The Rosetta lander’s instruments will obtain the first images from a comet’s surface and make the first in situ analysis to find out what it is made of.
• On its way to Comet 67P/Churyumov-Gerasimenko, Rosetta will pass through the main asteroid belt, with the option to be the first European close encounter with one or more of these primitive objects.
• Rosetta will be the first spacecraft ever to fly close to Jupiter’s orbit using solar cells as its main power source.

Scientists will be eagerly waiting to compare Rosetta’s results with previous studies by ESA’s Giotto spacecraft and by ground-based observatories. These have shown that comets contain complex organic molecules - compounds that are rich in carbon, hydrogen, oxygen and nitrogen.

Intriguingly, these are the elements which make up nucleic acids and amino acids, the essential ingredients for life as we know it. Did life on Earth begin with the help of comet seeding? Rosetta may help us to find the answer to this fundamental question.

ESA

About Rosetta…

• Europe's comet chaser
• Why 'Rosetta'?
• History of cometary missions

About comets …

• Comets - an introduction
• How many comets are there?
• Where life began
• Debris of the Solar System: Asteroids

About the spacecraft…

• The Rosetta orbiter
• Orbiter: Instruments
• The Rosetta lander
• Lander: Instruments

About the journey…

• The long trek
• Life and survival in deep space
• Long-distance communication
• The Rosetta ground segment

About the arrival…

• Comet 67P/Churyumov- Gerasimenko
• Comet rendezvous

Multimedia

VideoTalk

3D Flash 'model'

Rosetta images

Rosetta videos

Rosetta wallpaper

Services

Frequently asked questions

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com

ESA - Explosive crater twins on Mars

Arima twins

11 April 2013 Dramatic underground explosions, perhaps involving ice, are responsible for the pits inside these two large martian impact craters, imaged by ESA’s Mars Express on 4 January.
The ‘twin’ craters are in the Thaumasia Planum region, a large plateau that lies immediately to the south of Valles Marineris, the largest canyon in the Solar System.
The northernmost (right) large crater in this scene was officially given the name Arima in early 2012, but the southernmost (left) crater remains unnamed. Both are just over 50 km wide and display intricate interior features.

Inside a central pit crater

The southernmost crater is also presented here in a perspective view, revealing its complex characteristics in detail.
Multiple terraces slump from the crater walls onto a flat floor, but perhaps the most striking feature is the central pit, a feature it shares with Arima crater to its north.

Arima twins in context

Central pit craters are common on Mars, as well as on the icy moons orbiting the giant planets in our Solar System. But how did they form?
When an asteroid hits the rocky surface of a planet, both it and the surface are compressed to high densities. Immediately after the impact, the compressed regions rapidly depressurise, exploding violently.  
In low-energy impacts, a simple bowl-shaped crater results. In more dramatic events, larger craters are produced with more complex features, such as uplifted central peaks or sunken pits.
One idea for central pit formation is that when rock or ice melted during the impact drains away through fractures beneath the crater, it leaves a pit.
Another theory is that subsurface ice is rapidly heated, vapourising in an explosion. As a result, the rocky surface is excavated forming an explosive pit surrounded by rocky debris. The pit is in the centre of the main crater, where most of the impact energy was deposited.

Arima twins topography

Though the large craters in this scene have similar diameters, their central pits are rather different in size and depth, as is clearly evident in the topographical map. Compared to the Arima crater, perhaps more subsurface ice was present and more readily vapourised in the southern crater, punching through slightly thinner crust to leave a larger pit.
Many neighbouring small impact craters also show evidence for subsurface water or ice at the time of impact as evidenced by their ‘rampart’ ejecta blankets.
Ejecta blankets are debris deposits surrounding the crater, excavated from inside the crater during its formation. They have petal-like lobes around their edges: these result from liquid water bound up in the ejected material, allowing it to flow along the surface and giving it a fluid appearance.

Arima twins in 3D

Impact craters like these can thus provide windows into the past of a planet’s surface. In this case, they provide evidence for the Thaumasia Planum region having once hosted plentiful subsurface water or ice that was liberated during impact events both small and large.

RELATED ARTICLES:

Digging for hidden treasure on Mars25 March 2013

Digging for hidden treasure on Mars25 March 2013 ESA’s Mars Express has spent nearly ten years imaging the Red Planet, and there are plenty of hidden treasures buried in the mission’s rich picture archive.

At the mouth of the red valley14 February 2013

Mapping Mars04 February 2013

ESA

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com

ESA- SPACE IMAGEN - The solar wind is swirly

Tiny turbulent swirls in the solar wind.

Using ESA’s Cluster quartet of satellites as a space plasma microscope, scientists have zoomed in on the solar wind to reveal the finest detail yet, finding tiny turbulent swirls that could play a big role in heating it.

Turbulence is highly complex and all around us, evident in water flowing from a tap, around an aircraft wing, in experimental fusion reactors on Earth, and also in space.

In the stream of charged particles emitted by the Sun – the solar wind – turbulence is thought to play a key part in maintaining its heat as it streams away and races across the Solar System.

As the solar wind expands, it cools down, but to a much smaller extent than would be expected if the flow were smooth.

Turbulence arises from irregularities in the flow of particles and magnetic field lines, but understanding how this energy is transferred from the large scales where it originates, to the small scales where it is dissipated, is like trying to trace energy as it is transferred from the smooth, laminar flow of a river down to the small turbulent eddies formed at the bottom of a waterfall.

In a new study, two of the four Cluster satellites have made extremely detailed observations of plasma turbulence in the solar wind.

They were separated by just 20 km along the direction of the plasma flow and operated in ‘burst mode’ to take 450 measurements per second.

By comparing the results with computer simulations, scientists confirmed the existence of sheets of electric current just 20 km across, on the borders of turbulent swirls.

“This shows for the first time that the solar wind plasma is extremely structured at this high resolution,” says Silvia Perri of the Universita della Calabria, Italy, and lead author of the paper reporting the result.

Cluster previously detected current sheets on much larger scales of 100 km in the magnetosheath, the region sandwiched between Earth’s magnetic bubble – the magnetosphere – and the bow shock that is created as it meets the solar wind.

At the borders of these turbulent eddies the process of ‘magnetic reconnection’ was detected, whereby oppositely directed field lines spontaneously break and reconnect with other nearby field lines, thus releasing their energy.

“Although we haven’t yet detected reconnection occurring at these new, smaller scales, it is clear that we are seeing a cascade of energy which may contribute to the overall heating of the solar wind,” said Dr Perri.  

Future missions such as ESA’s Solar Orbiter and NASA’s Solar Probe Plus will be able to determine whether similar processes are also in play closer to the Sun, while NASA’s Magnetospheric Multiscale mission will specifically probe the small-scale regions where reconnection can occur.

“This Cluster result demonstrates the mission’s unique capability to probe universal physical phenomena, in this case pushing the mission’s instrument measurement capabilities to their limit to unlock features at small scales,” comments Matt Taylor, ESA’s Cluster Project Scientist.

“Future multi-spacecraft missions will make very detailed studies of these small-scale plasma phenomena and provide further context to our Cluster measurements.”

 ESA

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com

 

ESA Portal - Titan’s seasons make sharp turn

Vortex on Titan close up

Download:

 HI-RES JPEG (Size: 151 kb)  HI-RES TIFF (Size: 724 kb) 

A true-colour image of the south pole vortex observed in Titan’s atmosphere at about 200–300 km altitude, as seen during a Cassini flyby of Saturn’s largest moon on 27 June 2012. Since equinox in August 2009, the seasons have been changing, becoming spring in the northern hemisphere and autumn in the southern hemisphere. The formation of the vortex over the south pole indicates the effect of the changing seasons on the circulation pattern in Titan’s atmosphere, specifically with cooler air sinking down from warmer, high altitudes. The images were obtained with the Cassini spacecraft narrow-angle camera at a distance of approximately 484,000 kilometres from Titan. 

Credits: NASA/JPL–Caltech/Space Science Institute

Scientists using the international Cassini spacecraft have studied the rapid change in seasons on Saturn’s moon Titan, following equinox in August 2009, which saw the formation of a swirling vortex and a build up of exotic gases at unexpectedly high altitudes.

Titan is the only other body in the Solar System with a thick nitrogen-rich atmosphere like Earth’s. Titan’s atmosphere also contains methane and hydrogen, with trace amounts of other gases including hydrocarbons that form at high altitudes as a result of reactions with sunlight.

These complex molecules filter down into the lower atmosphere and eventually combine to produce an orange smog.

A separate layer of haze is found at a much higher altitude of 400–500 km and can be seen at the limb of the moon, apparently detached from the rest of the atmosphere.

This haze was thought to represent the ceiling of Titan’s ‘middle atmosphere’ circulation which extends from pole to pole in one giant cell, but new results from Cassini suggest otherwise. 

Titan’s changing seasons

Download:

 HI-RES JPEG (Size: 905 kb)  HI-RES TIFF (Size: 14 407 kb) 

Artist’s impression of the change in observed atmospheric effects before, during and after equinox in 2009. The Titan globes also provide an impression of the detached haze layer that extends all around the moon (blue).

During the first years of Cassini’s exploration of the Saturnian system, Titan sported a ‘hood’ of dense organic gases (white) in a vortex above its north pole, along with a high-altitude ‘hot spot’ (red). During this time the north pole was pointed away from the Sun.

At equinox both hemispheres received equal heating from the Sun. Afterwards, the north pole tilted towards the Sun, signalling the arrival of spring, while the southern hemisphere tilted away from the Sun and moved into autumn.

After equinox and until 2011 there was still a significant build up of trace gases over the north pole, but the vortex winds had significantly reduced and the hot spot had almost disappeared. Instead, similar features began developing at the south pole, which are still present today.

These observations are interpreted as a large-scale reversal in the single pole-to-pole atmospheric circulation cell of Titan immediately after equinox, with an upwelling of gases in the summer hemisphere and a corresponding downwelling in the winter hemisphere.

This graphic is based on data from the Cassini mission, a partnership among NASA, ESA and the Italian Space Agency. 

Credits: ESA/AOES

 When Cassini arrived in the Saturn system in 2004, Titan sported a vortex with a ‘hood’ of enriched gas and dense haze high above its north, winter pole. After equinox in August 2009, spring arrived in the moon’s northern hemisphere while the southern hemisphere headed towards autumn.

The change in solar heating was reflected by a rapid reversal in circulation direction in Titan’s single pole-to-pole atmospheric cell, with an upwelling of gases in the summer hemisphere and downwelling in the winter hemisphere.

“Even though the amount of sunlight reaching the south pole was decreasing, the first thing we saw there during the six months after equinox was actually an increase in temperature at altitudes of 400–500 km, as atmospheric gases that had been lofted to these heights were compressed as they subsequently sank into a newly forming southern vortex,” says Dr Nick Teanby from the University of Bristol, UK, and lead author of the study reported in the journal Nature.

“This heating effect is the same one that causes compressed air in a bicycle pump to heat up, and provided the smoking gun that the change in seasons was underway.”
 
 In the months that followed, up to a hundred-fold increase in atmospheric gas concentration was measured over the south pole at the same high altitudes.

Cassini’s instruments found that these gas molecules were sinking through the atmosphere at a rate of 1–2 millimetres per second.

Dr Teanby’s team conclude that for the enrichment and motion to be seen throughout these altitudes, the actual source of the complex gas molecules must be higher still, and that the detached haze layer cannot signal the top of the atmospheric circulation cell.

The new observations instead suggest that these complex haze molecules are produced higher up, but that when they drop down to the 400–500 km level, a change in the character of the haze takes place, perhaps as individual particles clump together.

“It’s impressive to see such dramatic solar-driven seasonal changes on a world where the sunlight is nearly a hundred times weaker than it is on Earth,” adds Dr Teanby.

“Since a year on Titan is nearly 30 Earth years long, for the atmosphere to change over a period of just six months is extremely rapid.”

“Models have predicted this change in Titan’s atmospheric circulation for nearly 20 years, but Cassini has provided the first direct observations of it actually happening,” says Nicolas Altobelli, ESA’s Cassini project scientist.
Notes for Editors
ESA

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com