Just released "farewell photo" taken by the Philae lander as it departed Rosetta around 2:30 a.m. (CST) today. It shows the one of the solar arrays. Credit: ESA/Rosetta/Philae/CIVA
Anticipation is intense as the Philae lander free-falls to the surface of Comet Churyumov-Gerasimenko this morning. The final “Go” for separation from the Rosetta spacecraft was given around 2:30 a.m.; Philae’s now well on its way to Agilkia, the target landing site atop the 67P/C-G’s largerEverything is running smoothly except for one potential problem. During checks on the lander’s health, it was discovered that the active descent system, which provides a thrust to avoid rebound at the moment of touchdown, can’t be activated.
Artist impression of Philae separating from Rosetta earlier this morning. The lander is now free-falling to the comet under the influence of its gravity. Credit: ESA
At touchdown, as Philae anchors itself to the comet with harpoons and ice screws on each of its legs, the thruster on top of the lander is supposed to push it down to counteract the force of the harpoon firing in the opposite direction.
Klim Churyumov (left) Svetlana Gerasimenko are both at ESA today during the historic landing on the comet they discovered on September 20, 1969. Credit: ESA TV
“The cold gas thruster on top of the lander does not appear to be working so we will have to rely fully on the harpoons at touchdown,”says Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.
The Philae that could! The lander photographed during its descent by Rosetta. Credit: ESA/Rosetta/MPS for Rosetta Team/
Philae is on target to land on the comet around 9:37 a.m. CST (15:37 UT). Confirmation of touchdown will take about 28 minutes as the signal, traveling at the speed of light, works its way back on Earth. As Philae floats down to the comet it not only has to deal with the 67P/C-G’s gravity but also the cloud of dust and ice grains escaping from the surface. Check back for regular updates and photos!
Tense control room during the Philae landing confirmation Time: 9:48 a.m. CST. Credit: ESA
Magnetic field lines bound up in the sun’s wind pile up and drape around a comet’s nucleus to shape the blue ion tail. Notice the oppositely-directed fields on the comet’s backside. The top set points away from the comet; the bottom set toward. In strong wind gusts, the two can be squeezed together and reconnect, releasing energy that snaps off a comet’s tail. Credit: Tufts University
Tune in to the song of Comet Churyumov-Gerasimenko
Scientists can’t figure exactly why yet, but Comet 67P/Churyumov-Gerasimenko has been singing since at least August. Listen to the video – what do you think? I hear a patter that sounds like frogs, purring and ping-pong balls. The song is being sung at a frequency of 40-50 millihertz, much lower than the 20 hertz – 20 kilohertz range of human hearing. Rosetta’s magnetometer experiment first clearly picked up the sounds in August, when the spacecraft drew to within 62 miles (100 km) of the comet. To make them audible Rosetta scientists increased their pitch 10,000 times.
The sounds are thought to be oscillations in the magnetic field around the comet. They were picked up by the Rosetta Plasma Consortium, a suite of five instruments on the spacecraft devoted to observing interactions between the solar plasma and the comet’s tenuous coma as well as the physical properties of the nucleus. A far cry from the stuff you donate at the local plasma center, plasma in physics is an ionized gas. Ionized means the atoms in the gas have lost or gained an electron through heating or collisions to become positively or negatively charged ions. Common forms of plasma include the electric glow of neon signs, lightning and of course the Sun itself.
Having lost their neutrality, electric and magnetic fields can now affect the motion of particles in the plasma. Likewise, moving electrified particles affect the very magnetic field controlling them.
Scientists think that neutral gas particles from vaporizing ice shot into the coma become ionized under the action of ultraviolet light from the Sun. While the exact mechanism that creates the curious oscillations is still unknown, it might have something to do with the electrified atoms or ions interacting with the magnetic fields bundled with the Sun’s everyday outpouring of plasma called the solar wind. It’s long been known that a comet’s electrified or ionized gases present an obstacle to the solar wind, causing it to drape around the nucleus and shape the streamlined blue-tinted ion or gas tail.
“This is exciting because it is completely new to us. We did not expect this, and we are still working to understand the physics of what is happening,” said Karl-Heinz Glassmeier, head of Space Physics and Space Sensorics at the Technical University of Braunschweig, Germany.
While 67P C-G’s song probably won’t make the Top 40, we might listen to it just as we would any other piece of music to learn what message is being communicated.
On a hiking holiday in the Swiss Alps this summer, it struck me that an Alpine setting — or its equivalent in other countries – looking at kilometer-sized objects at distances up to a dozen or dozens of kilometers is probably the situation where we can best develop an intuition about just how large the nucleus of 67P/Churyumov–Gerasimenko is.
Today, I took the time to insert the nucleus in one of my holiday snaps, using one of the Rosetta Navcam images that ESA has just released under a Creative Commons license. My original image was taken from a hiking trail between the Swiss villages of Bettmeralp and Fiescheralp, looking South-East towards Italy. The first image, above, has the comet floating just behind the first mountain range in the Binntal valley.
This is a fairly big sucker, even compared with the mountains in front and behind. In this image, the cometary nucleus is at a distance of about 7.2 kilometers (4.3 miles) from the observer.
I’ve also set the nucleus a bit farther back: Just beyond the most distant mountain range dominating the center of the image, which includes Italy’s Mount Cervandone, 3210 meters (10,530 ft.) high. It’s sitting right beyond the most distant mountain range visible in the original image (at a distance of about 14 km [8.7 mi] from the observer), and still looks fairly impressive:
Image credit: M. Pössel/HdA using an image from ESA/Rosetta/NAVCAM. Released under CC BY-SA IGO 3.0
And this, I guess, makes a cometary nucleus a nice link between the terrestrial and the cosmic: It is comparable to the largest structures we can directly see here on Earth, and does not have the enormous (astronomical!) dimensions so often encountered in space, whose size we cannot directly imagine.
On November 12, we’ll hopefully have another comparison: How will the view transmitted by the Philae lander correspond to terrestrial landscapes? What impression of size will we get then? Good luck, Rosetta and Philae!
Production notes
The images were made from two images shot with a Canon 70D with the standard kit lens – one showing the landscape, and a separate one showing more suitable sky and clouds on a different day, in a different location. Using Gimp, I inserted a fairly well-known Navcam image from ESA’s Flickr collection. The image came with the information that its resolution was 5.3 m per pixel; I used this plus distance information from Google Maps and elevation information via Mapcoordinates, combined with a test image giving me my camera’s pixel scale, to estimate the appropriate size of the cometary nucleus in the image (no lens distortion; camera modeled as a simple pinhole camera).
Rosetta, the scientific mission to explore a comet's surface. "Ambition", a short Sci-Fi film, set in the near future, and Rosetta, the children's fable, to encourage the next generations to undertake on the great adventures still to come. (Photo Credits: ESA, Platige Image, ESA Communications)
In the recently released Rosetta short film called “Ambition”, the master begins a story to his apprentice – “Once upon a time.” The apprentice immediately objects to his triteness. But he promises that it is worth the slight tribulation. Who could have imagined ten years ago that Rosetta would become so successful in two such contrasting approaches to telling a tale.
The Rosetta mission is part franchise and part scientific mission. In five days, Rosetta will reach a crossroad, a point of no return as epic as moments in Harry Potter or Lord of the Rings. A small mindless little probe called Philae will be released on a one-way trip to the surface of a comet. Win or lose, Philae will live on in the tale of a comet and a mission to uncover the mysteries of our planet’s formation.
ESA did not promise a good mission as Aidan Gillen promises a good story in Ambition. A space mission is never put in terms of a promise but rather it is thousands of requirements and constraints that formulate a mission plan and a spacecraft design. The European Space Agency put 1 billion Euros ($1.3 billion) to work and did so in what now looks like one of the greatest space missions of the first century of space exploration.
The Rosetta mission is actually two missions in one. There is the comet chaser, the orbiter – Rosetta and then the lander Philae. The design of Rosetta’s objectives is some part, probably in large part, was conceived by dismissing the presence of Philae. Make a space probe to a comet that just orbits the small body. Select your scientific instrumentations accordingly. Now add a small lander to the mission profile that will do something extraordinary – what Rosetta cannot do with its instrumentation. Finally, make sure that Rosetta has everything needed to support Philae’s landing on a comet.
Here is what they have as the game plan on November 12th (the sequence of events begins while its still November 11th in the Americas). These two times are absolutely non- trivial. They are finely tuned to a timepiece called 67P/Churyumov–Gerasimenko. If calculations were made in error, then Philae’s ultimate fate is unknown. Start exactly on time and Philae will be given the best chance at making a successful touchdown on the comet.
Separation of Philae from Rosetta: 09:03 GMT (10:03 CET)
Touchdown on the comet: 16:02 GMT (17:02 CET).
During this time, comet 67P/Churyumov–Gerasimenko will complete over half a rotation on its axis. To be exact, it will rotate 56.2977% of a full rotation. Comet 67P will have its back turned towards Rosetta as it holds the diminutive Philae for the last time and releases Philae for the first and only time.
Now that the ESA, with help from the graphic artists from Platige Image from Poland, has released something entertaining for the science fiction minded among us, they have again released a next episode in their children’s fable of Rosetta and Philae (video below). This cartoon of the final moments of Rosetta and Philae together preparing for the descent which could well be the final moments of Philae.
Philae could fail, crack like an egg on a sharp rock or topple over a cliff or into a crevasse on the surface of 67P. What happens to Philae will make for a Grimm’s fairy tale ending or something we would all prefer. In either case, the ESA is using graphic arts and storytelling to inspire the next generations to join in what our JFK called “great adventures of all time” [ref].
Through a contest something NASA and JPL have used several times to involve the public, the ESA asked the public to come up with a name for the landing site, site J. Out of the thousands of entries, 150 people suggested the name Agilkia [ref]. Alexandre Brouste from France, the designated winner, has been invited to watch the landing activities at Rosetta’s mission control in Darmstadt, Germany. It follows from the Eqyptian theme of the mission’s two probes. “Rosetta” comes from the clay tablet discovered in the 1800s that led to the deciphering of Egyptian hieroglyphics. Philae” is a island on the Nile which held magnificent Eqyptian temples. With the operation of the Aswan dam starting in 1902, the island of Philae was repeatedly flooded and the temple was at risk. UNESCO beginning in 1960 started a project to save the islands historic structures. They were all moved to a nearby Nile island called Agilkia [related U.T. article]. This becomes a part of the Rosetta story – a lander named Philae in reference to the obelisks used along with the Rosetta stone to decipher Eqyptian writings, departing its mother ship on a short but critical voyage to a final resting place, the landing site now called Agilkia.
Upon landing, a landing confirmation signal is expected from Philae via Rosetta at about 8:02 AM PST (11:02 AM EST, 17:02 Central European Time). Alexandre Brouste of France, the designated winner of the landing site naming contest will be in Darmstadt, Germany in mission control to watch the landing unfold with the Rosetta engineers and scientists. Surely, millions of citizens of the European Union and people worldwide will be watching via the World Wide Web.
The timeline and events to unfold as Philae, the lander is released from Rosetta, the comet orbiter. (Illustration Credit: ESA)
Previous Rosetta and Philae articles at Universe Today
This "dark side" image of Comet 67P/Churyumov-Gerasimenko shows light backscattered from dust particles in the coma surrounding the comet, which helps scientists search for surface features. The picture was taken by the Rosetta spacecraft Sept. 29 from about 19 kilometers (12 miles). Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
How do you see a side of a comet that is usually shrouded in darkness? For the plucky scientists using the Rosetta spacecraft, the answer comes down to using dust to their advantage. They’re trying to catch a glimpse of the shadowed southern side using light scattering from dust particles in anticipation of watching the comet’s activity heat up next year.
Using Rosetta’s OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) instrument, scientists are diligently mapping Comet 67P/Churyumov-Gerasimenko’s surface features as it draws closer to the Sun. Funny enough, the shadowed side will be in full sunlight by the time the comet gets to its closest approach. This gives scientists more incentive to see what it looks like now.
The comet side is in shadow because its is not perpendicular to its orbital plane, the Max Planck Institute for Solar System Research stated. This means that areas of the comet can stay in shadow for months at a time. But using OSIRIS’ powerful receptors, scientists can get a few hints about what those surface features are, using dust scattering.
Playing with saturation levels in these images, scientists using the Rosetta’s spacecraft imaging system are able to get more information about surface features in the image at right. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
“For a normal camera, this tiny bit of scattered light would not help very much”, stated OSIRIS team member Maurizio Pajola from the University of Padua in Italy. A normal camera has eight bits per pixel of information (256 shades of gray), while OSIRIS’ 16 bits allow it to distinguish between 65,000 shades. “In this way, OSIRIS can see black surfaces darker than coal together with white spots as bright as snow in the same image,” he added.
The scientists were not specific in a press release about what they are seeing so far, but they said that in May 2015 they expect to get a lot more data very quickly — once the area goes into full sunlight.
Rosetta, a mission of the European Space Agency, has been orbiting the comet since August. Next Wednesday it will release a lander, Philae, that will attempt to make the first soft landing on a comet’s surface.
Philae's landing site, dubbed Agilkia, as seen by the Rosetta spacecraft on Oct. 30, 2014. The spacecraft was 26.8 km (16.7 miles) from the comet's center when the picture was taken. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0
After sifting through 8,000 entries in multiple languages — even in Esperanto! — the contest to name Philae’s landing site on Comet 67P/Churyumov–Gerasimenko has resulted in an Egyptian-themed name.
The European Space Agency lander will touch down on the comet on a site dubbed “Agilkia”, which is named after an Egyptian island that hosts the Temple of Isis and other buildings that previously were on the island Philae. The buildings were moved due to the Aswan dams flooding Philae in the past century.
Agilkia, which was voted for by more than 150 people, fits in perfectly with ESA’s decision to informally name features on the comet after Egyptian names. Mission planners for the Rosetta orbiter and its lander, Philae, previously dubbed the site “J” before the landing contest was announced.
NAVCAM image of the comet on 21 September, which includes a view of primary landing site J. Click for more details and link to context image. (Credits: ESA/Rosetta/NAVCAM)
“The decision was very tough,” stated steering committee chair Felix Huber, who is with the DLR German Aerospace Center. “We received so many good suggestions on how to name Site J, and we were delighted with such an enthusiastic response from all over the world. We wish to thank all participants for sharing their great ideas with us.”
Alexandre Brouste from France was voted the overall winner and will be invited to follow the Nov. 12 landing live at ESA’s Space Operations Control Centre in Darmstadt, Germany. The landing is expected to take place around 12 p.m. Eastern (4 p.m. UTC), and you can follow the livestream here.
Ambition is a collaboration between Platige Image and ESA. Shot on location in Iceland, it is directed by Tomek Bagi?ski and stars Aiden Gillen and Aisling Franciosi. Does Ambition accomplish more in 7 minutes than Gravity did in 90? Consider the abstraction of the Rosetta mission in light of NASA’s ambitions. (Credit: ESA, Illustration- TRR)
NASA has taken on space missions that have taken years to reach their destination; they have more than a dozen ongoing missions throughout the Solar System and have been to comets as well. So why pay any attention to the European Space Agency’s comet mission Rosetta and their new short film, “Ambition”?
‘Ambition’ might accomplish more in 7 minutes than ‘Gravity’ did in 90.
‘Ambition’ is a 7 minute movie created for ESA and Rosetta, shot on location in Iceland, directed by Oscar-winning Tomek Baginski, and stars Aidan Gillen—Littlefinger of ‘Game of Thrones.’ It is an abstraction of the near future where humans have become demigods. An apprentice is working to merge her understanding of existence with her powers to create. And her master steps in to assure she is truly ready to take the next step.
In the reality of today, we struggle to find grounding for the quest and discoveries that make up our lives on a daily basis. Yet, as the Ebola outbreak or the Middle East crisis reminds us, we are far from breaking away. Such events are like the opening scene of ‘Ambition’ when the apprentice’s work explodes in her face.
The ancient Greeks also took great leaps beyond all the surrounding cultures. They imagined themselves as capable of being demigods. Achilles and Heracles were born from their contact with the gods but they remained fallible and mortal.
The Comet Rendezvous and Flyby Mission conceived in one of two Mariner Mark II spacecraft was abandoned by the US Congress. The American led mission would have accomplished the objectives now being completed by the European Rosetta mission. (Photo Credit: NASA)
But consider the abstraction of the Rosetta mission in light of NASA’s ambitions. As an American viewing the European short film, it reminds me that we are not unlike the ancient Greeks. We have seen the heights of our powers and ability to repel and conquer our enemies, and enrich our country. But we stand manifold vulnerable.
In ‘Ambition’ and Rosetta, America can see our European cousins stepping ahead of us. The reality of the Rosetta mission is that a generation ago – 25 years — we had a mission as ambitious called Comet Rendezvous Asteroid Flyby (CRAF). From the minds within NASA and JPL, twin missions were born. They were of the Mariner Mark II spacecraft design for deep space. One was to Saturn and the other – CRAF was to a comet. CRAF was rejected by congress and became an accepted sacrifice by NASA in order to save its twin, the Cassini mission.
The short film ‘Ambition’ and the Rosetta mission is a reminder of what American ambition accomplished in the 60’s – Apollo, and the 70s – the Viking Landers, but then it began to falter in the 80s. The ambition of the Europeans did not lose site of the importance of comets. They are perhaps the ultimate Rosetta stones of our star system. They are unmitigated remnants of what created our planet billions of years ago unlike the asteroids that remained close to the Sun and were altered by its heat and many collisions.
Artist Illustration of the Cassini space probe to Saturn and Titan, a joint NASA, ESA mission. Cassini was the only Mariner Mark II spacecraft completed. (Photo Credit: NASA)
Our cousins picked up a scepter that we dropped and we should take notice that the best that Europe spawned in the last century – the abstract art of Picasso and Stravinsky, rocketry, and jet travel — remains alive today. Europe had the vision to continue a quest to something quite abstract, a comet, while we chose something bigger and more self-evident, Saturn and Titan.
‘Ambition’ shows us the forces at work in and around ESA. They blend the arts with the sciences to bend our minds and force us to imagine what next and why. There have been American epoch films that bend our minds, but yet sometimes it seems we hold back our innate drive to discover and venture out.
NASA recently created a 7 minute film of a harsh reality, the challenge of landing safely on Mars. ESA and Rosetta’s short film reminds us that we are not alone in the quest for knowledge and discovery, both of which set the stage for new growth and invention. America needs to take heed so that we do not wait until we reach the moment when an arrow pierces our heel as with Achilles and we succumb to our challengers.
A view of Comet 67P/Churyumov-Gerasimenko on Sept. 26, 2014 from the orbiting Rosetta spacecraft. Credit: ESA/Rosetta/NAVCAM
While you can’t smell in space — there is no medium to carry the molecules, the same reason you can’t hear things — you can certainly detect what molecules are emanating from comets and other solar system bodies. A new analysis of Comet 67P/Churyumov-Gerasimenko by the orbiting Rosetta spacecraft thus found a rather pungent chemistry combination.
The spacecraft detected hydrogen sulphide (the smell of rotten eggs), ammonia and formaldehyde with traces of hydrogen cyanide and methanol. But compared to the amounts of water and carbon monixide 67P has, these molecule concentrations are quite miniscule.
“This all makes a scientifically enormously interesting mixture in order to study the origin of our solar system material, the formation of our Earth and the origin of life,” stated the University of Bern’s Kathrin Altwegg, from the center of space and habitability.
“And after all: it seems like comet Churyumov was indeed attracted by comet Gerasimenko to form Churyumov-Gerasimenko, even though its perfume may not be Chanel No 5, but comets clearly have their own preferences.”
More seriously, astronomers do say that at three astronomical units (Earth-Sun distances) from the Sun, the comet is emitting more molecules than expected. The next step will be to compare Rosetta’s data with ground-based data of other comets to see if this is common.
This Rosetta image of Comet 67P/Churyumov-Gerasimenko shows spectacular jets erupting from the small body on Sept. 10, 2014. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Jet! The comet that the Rosetta spacecraft is visiting is shedding more dust as machine and Solar System body get closer to the Sun.
While activity was first seen at the “neck” of the rubber-duckie shaped comet a few weeks ago, now scientists are seeing jets spring from across the comet.
This is just one signal of cometary activity picking up as 67P gets closer to the Sun. For the moment, it appears the prime landing site is still safe enough for Philae to land on Nov. 19, officials said, while noting there is a jet about a kilometer away that the lander can study when it gets there.
Jets spring from the “neck” area of Comet 67P/Churyumov-Gerasimenko. The smaller lobe is on the left, and the larger on the right. These images were taken about 7.2 kilometers (4.5 miles) from the surface. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
“At this point, we believe that a large fraction of the illuminated comet’s surface is displaying some level of activity,” stated Jean-Baptiste Vincent a scientist from the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) that took the pictures. He is with the Max Planck Institute for Solar System Research in Germany.
The comet is about 470 million kilometers (292 miles) from the Sun and will make its closest approach in 2015. Rosetta is the first mission to orbit a comet as it gets close to the Sun, and Philae (if successful) will make the first “soft” landing on a cometary surface.
The Rosetta spacecraft takes a selfie Oct. 7 with its target, 67P/Churyumov–Gerasimenko, from an altitude of about 9.9 miles (16 kilometers). Credit: ESA/Rosetta/Philae/CIVA
The Philae spacecraft has a tough job ahead of it on November 12: it is slated to make the first landing on a comet’s surface. Riding piggyback on the Rosetta spacecraft, all indications are it is in good health and ready for the job; the team has even been taking the time for Philae to image spacecraft “selfies” with its target, Comet 67P/Churyumov–Gerasimenko, in the background.
And Rosetta will also be working hard, as the animation above shows us with the various maneuvers the spacecraft will be required to send Philae to the surface. Read more about these orbital changes below, as well as details of a contest to name the comet’s landing site.
As you can see in the animation, Rosetta starts in a 19 kilometer (11.8 mile) orbit, then moves down to the 10 km (6.2 mile) mapping orbit that it is right now.
Rosetta then does some maneuvers to get ready to send Philae to the surface, including a trajectory change about 2-3 hours before Philae’s landing. Rosetta will be about 22.5 km (14 miles) from the comet during the pre-separation phase. Then, the latter part of the animation shows Rosetta moving around to orbits ranging between 20 km and 50 km (12.4 miles and 18.6 miles) through December.
Meanwhile, here’s another way that certain people can get involved in the mission: the European Space Agency has a naming contest for the prime landing site!
“The rules are simple: any name can be proposed, but it must not be the name of a person,” ESA stated. “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.”
Full contest rules and details are available here. Hurry as the deadline is Oct. 22!
