ESA has given the green light for its Rosetta mission to deliver its lander, Philae, to the primary site on 67P/Churyumov–Gerasimenko on 12 November, in the first-ever attempt at a soft touchdown on a comet.
Philae’s landing site, currently known as Site J and located on the smaller of the comet’s two ‘lobes’, was confirmed on 14 October following a comprehensive readiness review.
Since the arrival, the mission has been conducting an unprecedented survey and scientific analysis of the comet, a remnant of the early phases of the Solar System’s 4.6 billion-year history.
At the same time, Rosetta has been moving closer to the comet: starting at 100 km on 6 August, it is now just 10 km from the centre of the 4 km-wide body. This allowed a more detailed look at the primary and backup landing sites in order to complete a hazard assessment, including a detailed boulder census.
The decision that the mission is ‘Go’ for Site J also confirms the timeline of events leading up to the landing.
Rosetta will release Philae at 08:35 GMT/09:35 CET on 12 November at a distance of approximately 22.5 km from the centre of the comet. Landing will be about seven hours later at around 15:30 GMT/16:30 CET. ...
16 October 2014 ESA and its Rosetta mission partners are inviting you to suggest a name for the site where lander Philae will touch down on Comet 67P/Churyumov–Gerasimenko on 12 November.
As the location of the first soft landing of a human-made object on a comet, the site, currently identified as Site J, deserves a meaningful and memorable name that captures the significance of the occasion.
The rules are simple: any name can be proposed, but it must not be the name of a person. The name must be accompanied by a short description (up to 200 words) explaining why this would make the ideal name for such an historic location.
A jury comprising members of the Philae Steering Committee will select the best name from the entries, and the winning proposer will be invited to follow the landing in person from ESA’s mission control centre in Darmstadt, Germany on 12 November.
The competition opens today and will run until 23:59 GMT on 22 October.
Svetlana Gerasimenko and Klim Churyumov, co-discoverers of comet 67P, pictured in 1975 with the 40-cm Zeiss astrograph in Dushanbe, Tajikistan. Image courtesy of K. Churyumov.
Rosetta's comet was discovered in 1969 by two Ukranian astronomers, Klim Churyumov and Svetlana Gerasimenko, who first observed it from the Institute of Astrophysics in Alma-Ata (now named Almaty), Kazakhstan. To their delight, comet 67P/Churyumov-Gerasimenko was selected in 2003 as the destination for the Rosetta mission. Since then, they have eagerly followed the progress of the mission that is now unveiling the many facets of 'their' comet.
Forty-five years after the discovery, Klim and Svetlana are still active researchers in the field of cometary science. They recently shared with us the story of how they stumbled on the object that would later become – as Svetlana calls it – a 'superstar among comets'.
20/10/2014 11:06 am
Copyright Image courtesy K. Churyumov
It was 45 years ago when astronomer Klim Churyumov and Svetlana Gerasimenko, one of his researchers, unwittingly began a new chapter in the history of space exploration.
During a comet-hunting expedition to Alma-Ata Observatory, Kazakhstan, they discovered the bizarre, ice-rich object – subsequently named Comet 67P/Churyumov–Gerasimenko – that is now under close scrutiny by ESA’s Rosetta spacecraft.
In November 2014 it is hoped that more secrets will be revealed when Rosetta’s Philae attempts the first soft-landing on the nucleus of a comet. ...
Since early August, the Rosetta Orbiter Sensor for Ion and Neutral Analysis (ROSINA) has been ‘sniffing the fumes’ of 67P/C-G with its two mass spectrometers.
As reported previously in this blog, even though the comet is still more than 400 million kilometres from the Sun, the mixture of molecules detected in the comet’s coma is surprisingly rich already. Before arriving at 67P/C-G, the ROSINA team thought that at these vast distances from the Sun, its relatively low intensity would only release the most volatile molecules via sublimation, namely carbon dioxide and carbon monoxide.
However, ROSINA has detected many more molecules.
...If you could smell the comet, you would probably wish that you hadn’t
As the Kathrin Altwegg, principal investigator for ROSINA, put it: “The perfume of 67P/C-G is quite strong, with the odour of rotten eggs (hydrogen sulphide), horse stable (ammonia), and the pungent, suffocating odour of formaldehyde. This is mixed with the faint, bitter, almond-like aroma of hydrogen cyanide. Add some whiff of alcohol (methanol) to this mixture, paired with the vinegar-like aroma of sulphur dioxide and a hint of the sweet aromatic scent of carbon disulphide, and you arrive at the ‘perfume’ of our comet.”
...
Margarita PS. The "smiley" is in Emily's original post - I didn't add it!
Comet 67P/Churyumov-Gerasimenko is showing a gradual, but clear, increase in activity, as can be seen in the latest images provided by the OSIRIS team.
While images obtained a few months ago showed distinct jets of dust leaving the comet, these were limited to the ‘neck’ region. More recently, images obtained by Rosetta’s scientific imaging system, OSIRIS, show that dust is being emitted along almost the whole body of the comet. Jets have also been detected on the smaller lobe of the comet.
... While 67P/C-G’s overall activity is clearly increasing, the mission’s designated landing site on the smaller lobe still seems to be rather quiet. However, there is some indication that new active areas are waking up about one kilometre from the landing site. These will allow the lander’s instruments to study the comet’s activity from an even closer distance. ...
Below: Two views of the same region on the neck of Comet 67P/Churyumov-Gerasimenko (the larger lobe is to the right and the smaller lobe is to the left in this orientation). The first image was taken with an exposure time of less than a second and shows details on the comet’s surface. The second image was overexposed (exposure time of 18.45 seconds) to bring out the details of the jets arising from the comet’s surface. The images were obtained by the OSIRIS wide-angle camera on 20 October 2014 from a distance of 7.2 kilometres from the surface.
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Rosetta conducted a manoeuvre today – a thruster burn that lasted 82 seconds – and it was completed as planned, Spacecraft Operations Manager Sylvain Lodiot has confirmed.
Today's manoeuvre is important as it means Rosetta has now started the transition from the COP to the pre-lander-delivery orbit.
Click to play embedded YouTube video.
Animation Published to YouTube on 15 Oct 2014
Animation showing Rosetta’s orbit in the lead up to, during and after lander separation.
The animation begins on 1 October 2014, when Rosetta is orbiting about 19 km from Comet 67P/Churyumov–Gerasimenko (all distances refer to the comet’s centre). The animation shows the transition to the close 10 km orbit by mid-October, and then the steps taken to move onto the pre-separation trajectory.
On the day of landing, 12 November, Rosetta makes a further manoeuvre 2–3 hours before separation to move to 22.5 km from the comet centre to deploy the lander, Philae. While Philae descends to the surface over a period of seven hours, Rosetta makes another manoeuvre to maintain visibility with the lander. A series of 'relay phase' manoeuvres then move Rosetta out to a distance of about 50 km, before moving first to a 30 km orbit and later to an orbit at about 20 km by early December.
The speed of the animation slows during the separation and lander phase to better highlight these events. The comet shape and rate of rotation is real – the comet rotates with a period of about 12.4 hours.
Early in September we reported that Rosetta’s COSIMA instrument, the COmetary Secondary Ion Mass Analyser, had detected its first dust grains. Now some results from the first compositional analyses are in, as Martin Hilchenbach reports for the COSIMA team:
...
One of the first grains to be analysed by COSIMA for its chemical mineral composition was the cometary dust grain that we’ve nicknamed Boris. Since we have to discuss a lot of our science and science planning over the phone, naming features or grains is essential for communication within the COSIMA team. But, while some team members were at first very thrilled to have a “personal” cometary grain, they pretty soon figured out that there was a tiny hitch attached: To get a first grip on the chemical composition, we have to shoot indium ions at the grain… so, COSIMA recently shot Boris and while the full analysis of this ‘incident’ is still pending, we would like to share the very first results and explain how this was achieved. ...
Margarita
Re: ESA: Rosetta: 100 days to wake-up
Posted: Sat Nov 01, 2014 12:04 am
by geckzilla
67P's smooth surface is looking not all that smooth upon closer inspection. The pixel scale here is about 65 cm / pixel when viewing original 1024x1024 size image (click for it).
Re: ESA: Rosetta: 100 days to wake-up
Posted: Sat Nov 01, 2014 4:01 pm
by MargaritaMc
geckzilla wrote:67P's smooth surface is looking not all that smooth upon closer inspection. The pixel scale here is about 65 cm / pixel when viewing original 1024x1024 size image (click for it).
Rosetta Blog 31 October 2014 writes:
... In a number of places in this region, there is an impression that the prevalent dusty material covering the surface is not particularly stable and that it occasionally gives way, perhaps in a similar way that snow on a mountain side may become dislodged, giving rise to an avalanche or, alternatively, a rockfall or landslide
.
For example, look in the lower third of the top left image. There you’ll see what looks like a crack close to the edge of the cliff, suggesting that this portion might eventually collapse, similar to the way a snow cornice on a mountain ridge peels away. This feature is also visible in the 8 October image. ...
There's a good discussion in the comment section, including input from the ESA team. Philae could be going to a layer of flour-like material...
Generally speaking, space missions fall into one of three categories: difficult, more difficult, and ridiculously difficult.
Flybys are difficult. A spaceship travels hundreds of millions of miles through the dark void of space, pinpoints a distant planet or moon, and flies past it at 20 to 30 thousand mph, snapping pictures furiously during an achingly brief encounter.
Going into orbit is more difficult. Instead of flying past its target, the approaching spaceship brakes, changing its velocity by just the right amount to circle the planet. One wrong move and the spacecraft bounces off the atmosphere, becoming an unintended meteor.
Landing is ridiculously difficult. Just play NASA's "Seven Minutes of Terror" video. Watching Curiosity parachute, retrorocket, and sky-crane its way to the surface of Mars rarely fails to produce goosebumps. Since the Space Age began, the space agencies of Earth have succeeded in landing on only six bodies: Venus, Mars, the Moon, Titan, and asteroids 433 Eros and Itokawa. ...
The site where Rosetta’s Philae lander is scheduled to touch down on Comet 67P/Churyumov–Gerasimenko on 12 November now has a name: Agilkia.
The landing site, previously known as ‘Site J’, is named for Agilkia Island, an island on the Nile River in the south of Egypt. A complex of Ancient Egyptian buildings, including the famous Temple of Isis, was moved to Agilkia from the island of Philae when the latter was flooded during the building of the Aswan dams last century. ...
"How hard is this landing?" asks Art Chmielewski, the US Rosetta Project Manager at JPL. "Consider this: The comet will be moving 40 times faster than a speeding bullet, spinning, shooting out gas and welcoming Rosetta on the surface with boulders, cracks, scarps and possibly meters of dust!"
Ps: NASA' s Space Place has a rather fun interactive game called Comet Quest
In "operating" Rosetta, you have five responsibilities:
Media and interested members of the public are invited to join Rosetta mission experts online on Friday, 7 November for a briefing ahead of the historic comet landing on 12 November.
Programme:
Introduction: Emily Baldwin, ESA space science editor
Overview of media events: Jocelyne Landeau-Constantin, Head of ESOC communication office
Science from Rosetta so far: Matt Taylor, ESA Rosetta project scientist
Spacecraft status and operations timeline: Andrea Accomazzo, ESA Rosetta flight director
Key messages: Fred Jansen, ESA Rosetta mission manager
Q&A: all
Post questions below or live on the day via G+ or on Twitter using the hashtag #AskRosetta . Note: Priority during the Q&A session is given to questions asked by members of the Media.
Rosetta and Philae cartoon about next week's landing
Posted: Wed Nov 05, 2014 1:40 pm
by MargaritaMc
Click to play embedded YouTube video.
Preparing for #CometLanding
European Space Agency, ESA
Published on 5 Nov 2014
After a ten-year journey, Rosetta and Philae had finally reached their destination, Comet 67P/Churyumov–Gerasimenko. Rosetta spent many weeks studying the comet, sending lots of information back to Earth. But where was Philae going to land? Eventually the scientists on Earth found the best place on the comet for Philae to land. Soon it was time to make the final preparations for Philae's great adventure. Both spacecraft couldn't wait any longer. The whole world would be watching as Rosetta and Philae prepared for their biggest challenge yet...
Margarita
Re: ESA: Rosetta: 100 days to wake-up
Posted: Wed Nov 05, 2014 2:01 pm
by Beyond
ESA does make some neat videos.
Re: ESA: Rosetta: 100 days to wake-up
Posted: Wed Nov 05, 2014 6:02 pm
by MargaritaMc
Beyond wrote:ESA does make some neat videos.
I loved the bit where Philae is packing a sandwich in his bag. As you say, these cartoons of Rosetta have all been rather good. Someone there has an excellent sense of humour.
M
MPS: Rosetta Glimpses the Dark Side of Comet 67P/C-G
[c]Image Credits: ESA/Rosetta/MPS for OSIRIS Team
MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA[/c]
Light scattered from dust particles allows a first glance at the side of comet 67P that has been trapped in the darkness of polar night for the last months.
Rosetta’s scientific imaging system OSIRIS has caught a glimpse of the southern side of comet 67P/Churyumov-Gerasimenko. During the past months, this side has continuously faced away from the Sun making it impossible to determine shape and surface structures. Only the light scattered from dust particles in the comet’s coma very slightly illuminates this uncharted territory.
Since ESA’s space probe Rosetta arrived at comet 67P/Churyumov-Gerasimenko in August, the scientific camera system OSIRIS has mapped most of its surface revealing stunning structures such as steep ravines, sharp cliffs and numerous boulders. 67P’s southern side, however, is still a mystery. As the comet’s rotation axis is not perpendicular to its orbital plane, but is tilted, parts of its surface can at times remain in total darkness. During the past months, 67P’s southern side has seen such a polar night, comparable to the weeks of complete darkness in Earth’s polar regions.
At the same time, 67P’s dark side promises to hold the key to a better understanding of the comet’s activity. “During perihelion, when 67P comes within approximately 186 million kilometers of the Sun, the comet’s southern side is illuminated and thus subjected to especially high temperatures and radiation”, says OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. Scientists therefore believe this side to be shaped most strongly by cometary activity. “We can hardly wait until May 2015, when the polar night ends and we can finally take a good look”, says Sierks.
Until then, a recent image offers a first taste of what will come. In this image sunlight backscattered from dust particles in the comet’s coma illuminates the comet’s dark side revealing a hint of surface structures. ...
Re: ESA: Rosetta: 100 days to wake-up
Posted: Fri Nov 07, 2014 3:03 pm
by MargaritaMc
Info is coming thick and fast from ESA as the time for Philae to (fingers crossed) land on the comet is approaching.
...All next week, I'll be in Darmstadt, Germany, at the European Space Operations Centre (ESOC), to witness the historic attempt at landing on a comet. I'm not going to lie to you: I'm going to be terrified about Philae's survival until I see ESA engineers leaping from their seats and cheering. To be clear, I have no specific doubts about the spacecraft or its designers. It's just that we have never landed on anything like a comet before. We don't really know what the surface of a comet is like -- is it a hard, crusty shell of rocky material? A diaphanously fluffy, almost cloud-like layer of highly porous dust? Gravelly? Crunchy? Crystalline? Powdery? Sandpapery? Slippery? Who knows? The last time we landed on a surface that we knew so little about was when ESA landed Huygens on Titan in 2004. But Huygens did almost all of its science on the way down, returning all its data to the Cassini orbiter in real time, so it didn't matter whether Huygens survived its arrival on Titan's surface. In contrast, almost all of Philae's science will not come until after a successful landing. It's going to be terrifying. But I wouldn't miss it for the world. ...
Edited to change URL of the hangout to the YouTube recording of the event. Which was very informative and worth watching. They had problems with screen share of PowerPoint slides - but promised that they can drive spacecraft with more skill!
NASA Television and the agency’s website will provide live coverage from 6-8:30 a.m. PST (9-11:30 a.m. EST) of the European Space Agency (ESA) Rosetta mission’s scheduled landing of a probe on a comet on Wednesday, Nov. 12.
NASA’s live commentary will include excerpts of the ESA coverage and air from 6-7 a.m. PST (9-10 a.m. EST). NASA will continue carrying ESA’s commentary from 7-8:30 a.m. PST (10-11:30 a.m. EST). ESA’s Philae (fee-LAY) lander is scheduled to touch down on comet 67P/Churyumov-Gerasimenko at 7:35 a.m. PST (10:35 a.m. EST). A signal confirming landing is expected at approximately 8:02 a.m. PST (11:02 a.m. EST).
After landing, Philae will obtain the first images ever taken from a comet’s surface. It also will drill into the surface to study the composition and witness close up how a comet changes as its exposure to the Sun varies. Philae can remain active on the surface for approximately two-and-a-half days. Its “mother ship” is the Rosetta spacecraft that will remain in orbit around the comet through 2015. The orbiter will continue detailed studies of the comet as it approaches the Sun and then moves away. NASA has three of the 16 instruments aboard the orbiter.
Comets are considered primitive building blocks of the solar system that are literally frozen in time. They may have played a part in “seeding” Earth with water and, possibly, the basic ingredients for life.
NB: WET means Western Europe Time and is also known as GMT and, loosely, is the same as UTC...
Here is the Livestream page
ESA will stay live until 19:00 GMT / 20:00 CET on 12 November with a permanent view of ESOC Mission Control Room in between the listed sequences.
As you say, these cartoons of Rosetta have all been rather good. Someone there has an excellent sense of humour.
