European Space Agency picks site for comet landing

[Buster's Uncle]

European Space Agency picks site for comet landing
Associated Press
By FRANK JORDANS  10 minutes ago



BERLIN (AP) — Talk about a moving target.

Scientists at the European Space Agency on Monday announced the spot where they will attempt the first landing on a comet hurtling through space at 55,000 kph (34,000 mph).

The maneuver is one of the key moments in the decade-long mission to examine comet 67P/Churyumov-Gerasimenko and learn more about the origins and evolution of objects in the universe.

"This is absolutely a unique mission, at the top of the bill," said mission manager Fred Jansen, comparing the complexity of landing on the 4-kilometer (2.5-mile) wide comet with that of landing a spacecraft on far larger objects like the moon or Mars.

The unmanned Rosetta probe has been flying alongside 67P since August, sending back high-resolution images that allowed scientists to shortlist five possible landing sites. They chose one — dubbed "J'' for now — based on its relatively safe terrain and proximity to interesting features on the comet.

But Stephan Ulamec, manager of the Philae lander project, said even with that site "the risk is high."

For one, scientists don't know how hard the comet's surface is, or how active it will be on Nov. 11. Like all comets, 67P's icy body has begun to fizz and spray matter as it nears the sun.

Another problem is that the comet has just 1/100,000th the gravity of Earth, so the 100-kilogram (220-pound) lander will have to use harpoons and screws to avoid bouncing back into the void.

Add to this the fact that the lander was designed 15 years ago, before ESA even knew which comet it would be aiming for.

Still, there will be no dress rehearsal, said Rosetta flight director Andrea Accomazzo: "Time has come to make it happen."

___

http://www.esa.int/rosetta


http://news.yahoo.com/european-space-agency-picks-comet-landing-095944724.html

[Buster's Uncle]

Rosetta team picks spot for historic comet landing
Reuters
By Victoria Bryan and Tim Hepher  2 hours ago



Rosetta, the European Space Agency's cometary probe with NASA contributions, is seen in an undated artist's rendering. REUTERS/ESA/NASA/Handout



BERLIN/PARIS (Reuters) - A team of scientists identified on Monday the point on the surface of a comet, known as "Site J," where they aim to land a probe in what would be a historic breakthrough for their decade-long project.

The probe or lander will be dispatched from the Rosetta spacecraft, which was launched by the European Space Agency (ESA) in 2004 and has been tracking comet 67P/Churyumov-Gerasimenko on its trip around the sun.

Scientists hope data the lander gathers on the surface of the comet will allow them to peek into a kind of astronomical time capsule that will offer clues about what the world looked like when our solar system was born.

The lander will drill more than 20 cm into the comet's surface to collect samples for analysis. By studying the comet's dust and gas, scientists hope to learn more about the role comets played in the development of Earth and the other planets in our solar system.

Timing is a vital part of the process. They need to wait until the comet has got close enough to the sun for the probe's solar panels to work, but must also land it before the increasing heat causes activity levels of the comet to rise so much that it would endanger a safe landing.

They have determined that a landing window will open up on Nov. 11, when the comet will be 450 million km from the sun.

Rosetta caught up with the comet in August and since then has been relaying pictures of the mass and its surface back to earth. While it is now within 30 km of the comet, the pictures are not of a high enough resolution to allow for detailed inspection of its surface.

"We don't know what the terrain looks like in detail," Paolo Ferri, head of mission operations at ESA, told Reuters ahead of the landing site decision. "But there's certainly no nice landing strip. We have to rush into this with the minimum amount of information."


PRECISION LANDING

Known as Philae, the three-legged lander must not descend too slowly or too quickly, its trajectory has to take into account the rotation of the comet, there has to be enough battery power left after landing to deploy its instruments, and detaching it from Rosetta has to be perfectly timed.

Once the box-shaped 100 kg probe has landed, the team will concentrate on setting up Philae's solar panels so it can start relaying data to Rosetta, which will continue to orbit the comet until at least of the end of 2015 and possibly longer if more funding can found.

An initial 10 landing sites had already been whittled down to five and a team of engineers and scientists met over the weekend to select one preferred site and one back-up.

The target Site J is on the "head" of the comet, an irregular body that is just over 4 km across at its widest point, the ESA said in a statement.

It said the chosen site offers "unique scientific potential, with hints of activity nearby, and minimum risk to the lander compared to the other candidate sites".

A backup, Site C, is located on the "body" of the comet.

Landing a probe is one of several historical firsts performed by the mission, including the first time a spacecraft orbits a comet rather than just whizzing past to snap pictures.

"Everything up until now has gone much better than we thought and hopefully it will continue," Ferri said.

(Editing by David Holmes and Keith Weir)


http://news.yahoo.com/rosetta-team-picks-spot-historic-comet-landing-113254222--sector.html

[Geo]

My "lector" yesterday was misinformed then. He said the choice would be made today between sites A and B.

[Buster's Uncle]

I'm surprised they went with a spot on the 'head', myself - I'd want a good view of the 'neck' to see the separation when it's going around the sun.

[Buster's Uncle]

'J' marks the spot for historic comet landing
AFP
By Richard Ingham  15 minutes ago



Picture taken by the European Space Agency's Rosetta space probe shows the Comet 67P/Churyumov-Gerasimenko from a distance of 285 kilometres (AFP Photo/)



Paris (AFP) - The European Space Agency on Monday unveiled the spot on a comet in deep space where it will attempt a high-stakes landing in November, a first for humankind.

The landing target is one of five that ESA shortlisted after its Rosetta spacecraft met up with Comet 67P/Churyumov-Gerasimenko in August, following a marathon chase across the cosmos.

Codenamed "J", the site offers the best chance for meeting scientific goals and for making a safe landing on an exceptionally difficult target, ESA said.

"The comet is a beautiful but dramatic world -- it is scientifically exciting, but its shape makes it operationally challenging," said Stephan Ulamec, in charge of the landing.

On November 11, Rosetta is scheduled to let down a robot lab called Philae to carry out experiments that scientists hope will shed light on these strange, icy bodies, which were born along with the Solar System.

Gently descending from a height of 10 kilometres (six miles), the 100-kilo (220-pound) lab will use harpoons to anchor itself and then drive screws into the surface for better grip.

Its experiments will include drilling up to 30 centimetres (18 inches) into the comet to extract pristine material for onboard chemical analysis.

Mission scientists had scrutinised five potential sites, named A, B, C, I and J, vetting each for the scientific return they offered, as well as landing risks and the amount of light available from the Sun for Philae's solar cells.

Comet "67P" comprises two lobes joined by a narrow neck, making it resemble a rubber duck -- though one that is pitch black, darker even than charcoal.



An artist's impression released by the European Space Agency on December 3, 2012 depicts the Rosetta spacecraft orbiting comet 67P/Churyumov–Gerasimenko (AFP Photo/C. Carreau / Medilab)


Three of the candidate sites were on the smaller lobe, or head of the "duck", and two on the larger lobe, or body. The oval-shaped landing site called "J" is roughly where the duck's forehead would be; a backup site, "C", is on the larger lobe.

Comets have in the past been considered iconic portents of good or evil.

Doomed to orbit the Sun, their outer layers are stripped by solar heat as they draw nearer, leaving a trail of dust and ice crystals that is reflected in sunlight and looks like a tail viewed from Earth.

Astrophysicists say they are balls of ancient ice and dust left from the building of the Solar System some 4.6 billion years ago.

This cosmic rubble is essentially a time capsule -- the oldest, least-touched material in our stellar neighbourhood -- and understanding them may advance knowledge of how Earth came to bear life.

Water and molecules providing the building blocks for life came from comets that whacked into the fledgling planet at a time when the Solar System was a shooting gallery, according to one theory.


- No spud in space -

Jean-Pierre Bibring, lead Philae scientist, said mission managers were initially dismayed when the weird shape -- two blobs joined by a neck -- hoved into view as Rosetta raced towards the target in July.

Conceived two decades ago, the mission had broadly expected a rounded, "potato-shaped" object which would have made a landing far easier, Bibring said at a press conference.

"We were very scared at the beginning," Bibring said.

Weeks of further work showed "reachable areas" where a landing could be made amid a jagged topography of cliffs, slopes, boulders and indentations.

Confirmation of the November 11 landing date is expected on September 26. ESA said it would also stage a competition for naming the site.

Rosetta, now looping around the comet at an altitude of 30 km, is equipped with 11 cameras and sensors that have already provided astonishing material.

But some of the biggest discoveries could be made by the 10 instruments aboard Philae, experts hope.

The four-km comet is on a 6.5-year Sun orbit.

Rosetta caught up with it after a six-billion-km trek that required four flybys of Earth and Mars, using the planets' gravity as a slingshot to build up speed.

At their closest approach on August 13, 2015, the comet and Rosetta will be 185 million km from the Sun.


http://news.yahoo.com/j-marks-spot-historic-rosetta-comet-landing-002904990.html

[Buster's Uncle]

The Big Picture: Scientists pick a landing site for their historic comet probe
Engadget
by Jon Fingas | @jonfingas | 2hs ago



Philae's landing site  [Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]



You're not just looking at an unassuming piece of rock -- if anything, it's a piece of history. That's Site J, the European Space Agency's long-awaited choice of landing spot for Philae, the first probe built to reach a comet's surface. Scientists chose the seemingly uneventful location because it should offer the best chances of studying the comet's nucleus and other material without worrying about impurities. It should also guarantee that Philae both stays in touch with its Rosetta mothership and maintains just enough power to get its job done. You'll likely have to wait until touchdown on November 11th to get a closer look, but this at least serves as a good preview.


http://www.engadget.com/2014/09/15/big-picture-comet-landing-site/?ncid=rss_truncated