Posts Tagged ‘European Space Agency’

Rosetta will be woken up Monday at 1000GMT after a two-and-a-half year sleep

January 19, 2014

The European Space Agency will try and wake-up its sleeping Rosetta spacecraft on Monday at 1000 GMT. The spacecraft entered deep space hibernation in June 2011 when it was too far away from the sun to capture much solar energy. If this works it will be a considerable achievement considering that Rosetta was launched 10 years ago  and the communications technology on board is effectively at least two  “generations” old!

Rosetta trajectory till June 2011

ESA:

At 10:00 GMT on Monday, the most important alarm clock in the Solar System will wake up ESA’s sleeping Rosetta spacecraft.

Rosetta is chasing comet 67P/Churyumov–Gerasimenko and, since its launch in 2004, has made three flybys of Earth and one of Mars to build up enough speed and get on a trajectory towards the comet. It has also encountered asteroids Steins and Lutetia along the way.

Operating on solar energy alone, the spacecraft was placed into a deep space slumber in mid-2011 as it cruised far from the Sun and out towards the orbit of Jupiter. To prepare for its long sleep, Rosetta was oriented so that its solar arrays faced the Sun and put into a once per minute spin for stability.

The only devices left running were its computer and several heaters.

Thirty-one months later, Rosetta’s orbit has brought it back to within ‘only’ 673 million kilometres of the Sun, and there is finally enough solar energy to power the spacecraft fully again. It is time to wake up.

Rosetta’s computer is programmed to carry out a sequence of events to re-establish contact with Earth on 20 January, starting with an ‘alarm clock’ at 10:00 GMT.

Immediately after, the spacecraft’s startrackers will begin to warm up, taking around six hours.

Then its thrusters will fire to stop the slow rotation. A slight adjustment will be made to Rosetta’s orientation to ensure that the solar arrays are still facing directly towards the Sun, before the startrackers are switched on to determine the spacecraft’s attitude.

Once that has been established, Rosetta will turn directly towards Earth, switch on its transmitter and point its high-gain antenna to send its signal to announce that it is awake.

Because of Rosetta’s vast distance – just over 807 million kilometres from Earth – it will take 45 minutes for the signal to reach the ground stations. The first opportunity for receiving a signal on Earth is expected between 17:30 GMT and 18:30 GMT.

Graphic of mission

Rosetta Mission (ESA via BBC)

Advertisements

New Doomsday possible on 13th April 2036 when asteroid Apophis could hit earth.

January 10, 2013

Yet another doomsday for us to look forward to (it gets boring looking back at doomsdays from the past that have failed to come to pass). This time it is a 325 m wide asteroid – named Apophis (Apep) after the Egyptian God of darkenss and chaos – which could crash into the Earth on 13th April 2036 (a Sunday).

My own hypothesis is that if we can increase the carbon dioxide in the atmosphere to around 1200 ppm, a collision could be avoided. All I need is some funding (just a few million would do) and I’m sure I could develop a suitable mathematical model to “prove” this. Maybe Greenpeace and WWF could contribute. After all it would save so many species on Earth – not to mention humans.

Daily Mail: The European Space Agency’s orbiting telescope has captured striking new images of the huge ‘Doomsday’ asteroid Apophis that could smash into Earth in 2036 – revealing it is larger than previously thought.

Long billed as a potential cause of an Extinction Level Event (ELE) for humanity, today ESA officials announced that its Herschel Space Observatory discovered that the asteroid is 1,066 feet wide, 20 percent larger than the previous estimate of 885 feet.

Whizzing past Earth at the relatively close distance of nine million miles tonight, Apophis is being closely tracked because of a 2004 study that predicted the rock has a 2.7 percent chance of hitting Earth in April 2029, which was later revised to 2036.

BBC: The large rocky mass was first discovered in 2004. At the time, it raised alarm when scientists calculated that it had a one-in-45,000 chance of smashing into the Earth in 2029.  Later revisions, lifted this threat; instead on the Friday 13 April 2029, it will make a close pass at a distance of about 30,000km. However, astronomers say there is still a one-in-200,000 chance that it could strike Earth in 2036.

Professor Alan Fitzsimmons, an astronomer at Queen’s University Belfast, UK, said: “In 2029, it will pass so close to us that Earth’s gravity will change its orbit. Most of the potential orbits it will end up on will mean we are safe for the next 100 years. But there is a small region of space – something we call a keyhole – and if it passes through that keyhole in 2029, it will come back and hit us on 13 April in 2036.”

If this happened, it would strike the Earth with 100 times the energy in our largest nuclear bombs, said Prof Fitzsimmons.

Signal received from Phobos Grunt

November 23, 2011

Breaking!

On Tuesday, 22 November at 20:25 UT, ESA’s tracking station at Perth, Australia, established contact with Russia’s Phobos-Grunt spacecraft. This was the first signal received on Earth since the Mars mission was launched on 8 November. ESA teams are working closely with engineers in Russia to determine how best to maintain communications with the spacecraft.

Mt. Etna bursts into life

January 14, 2011

The European Space Agency reports:

Sulphur dioxide plume over Mediterranean

This image, which was acquired by the Atmospheric Infrared Sounder on NASA's EOS-AQUA satellite, shows the plume of sulphur dioxide currently being carried over the Mediterranean Sea. Credits: NASA, Norwegian Institute for Air Research

13 January 2011


Europe’s largest active volcano, Mount Etna on the Italian island of Sicily, erupted briefly yesterday sending flames and ash hundreds of metres into the air.

This image, which was acquired by the Atmospheric Infrared Sounder on NASA’s EOS-AQUA satellite, shows the plume of sulphur dioxide currently being carried over the Mediterranean Sea.

The data have been processed by the Norwegian Institute for Air Research within the framework of ESA’s Data User Element and can be used to warn aviation companies on the hazardous plume.

File:Mount Etna snow-toppd.jpg

Mount Etna, Sicily, topped in snow 5 February 2009: image Wikimedia

Oxygen – carbon dioxide atmosphere found on Saturn’s moon Rhea

November 27, 2010

From The New Scientist:

On its journey around Saturn and its moons, the Cassini mission – jointly run by NASA and the European Space Agency – has made another breathtaking discovery. The findings, published in Science (DOI: 10.1126/science.1198366), show that Rhea, the second biggest moon of the giant planet, has an atmosphere that is 70 per cent oxygen and 30 per cent carbon dioxide. This adds to the picture of Rhea that Cassini has already provided by imaging its craters anddiscovering its rings.

“This really is the first time that we’ve seen oxygen directly in the atmosphere of another world”, Andrew Coates, from University College London’s Mullard Space Science Laboratory, told The Guardian. Layers containing oxygen had already been detected around the Jovian moons Europa and Ganymede in the 1990s, but only from a distance using NASA’s Hubble Space Telescope.

This time, Cassini’s instrument had the chance to “smell” that oxygen, as it flew through it over Rhea’s north pole, just 97 kilometres above the surface, according to the details given on Space.com. This layer – with an oxygen density probably about 5 trillion times less than on Earth – was “too thin to be remotely detected”, said Ben Teolis of the Southwest Research Institute in San Antonio.

These three views of Saturn's moon Rhea from NASA's Cassini spacecraft are enhanced to show colorful splotches and bands on the icy moon's surface. New observations have shown Rhea has an oxygen-rich atmosphere. Credit: NASA/JPL/SSI/LPI

Cassini Finds an Oxygen–Carbon Dioxide Atmosphere at Saturn’s Icy Moon Rhea B. D. Teolis, G. H. Jones, P. F. Miles, R. L. Tokar, B. A. Magee, J. H. Waite, E. Roussos, D. T. Young, F. J. Crary, A. J. Coates, R. E. Johnson, W.-L. Tseng and R. A. Baragiola

Science DOI: 10.1126/science.1198366, Published Online 25 November 2010

Abstract: The flyby measurements of the Cassini spacecraft at Saturn’s moon Rhea reveal a tenuous oxygen–carbon dioxide atmosphere. The atmosphere appears to be sustained by chemical decomposition of the surface water ice under irradiation from Saturn’s magnetospheric plasma. This in situ detection of an oxidizing atmosphere is consistent with remote observations of other icy bodies such as Jupiter’s moons Europa and Ganymede, and suggestive of a reservoir of radiolytic O2 locked within Rhea’s ice. The presence of CO2suggests radiolysis reactions between surface oxidants and organics, or sputtering and/or outgassing of CO2endogenic to Rhea’s ice. Observations of outflowing positive and negative ions give evidence for pickup ionization as a major atmospheric loss mechanism.


%d bloggers like this: