Rosetta Wows With Amazing Closeups of Comet 67P Before Final ‘Crunchdown’

Landscape on Comet 67P taken from just 10 miles (16 km) up late Thursday evening during Rosetta's free fall . The image measures 2,014 feet (614 meters) across or just under a half-mile. At typical walking speed, you could walk from one end to the other in 10 minutes. Credit: ESA/Rosetta
Craggy hills meet dust-covered plains in this landscape on Comet 67P taken from 10 miles (16 km) up late Thursday evening during Rosetta’s free fall . The image measures 2,014 feet (614 meters) across or just under a half-mile. At typical walking speed, you could walk from one side to the other in 10 minutes. This and all the photos below are copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta fell silent moments after 6:19 a.m. Eastern Time (12:19 UT) this morning, when it gently crashed into 67P/C-G 446 million miles (718 million km) from Earth. As the probe descended to the comet’s bouldery surface of the comet in free fall, it snapped a series of ever-more-detailed photographs while gathering the last bits data on the density and composition of cometary gases, surface temperature and gravity field before the final curtain was drawn.

Let’s take the trip down, shall we?

Rosetta's last navigation camera image was taken just after the collision maneuver sequence Thursday evening (CDT) when the probe was 9.56 miles (15.4 km) above the comet's surface. Credit: ESA/Rosetta
Rosetta’s last navigation camera image was taken just after the collision maneuver sequence Thursday evening (CDT) when the probe was 9.56 miles (15.4 km) above the comet’s surface. As in the photo above, much of the landscape is coated in a thick layer of dust that smoothes the comet’s contours.
As Rosetta continues its descent onto the Ma'at region on the small lobe of Comet 67P/Churyumov-Gerasimenko, the OSIRIS narrow-angle camera captured this image at 08:18 GMT from an altitude of about 5.8 km. The image shows dust-covered terrains, exposed walls and a few boulders on Ma'at, not far from the target impact region (not visible in this view - located below the lower edge).Copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
As Rosetta continued its descent onto the Ma’at region on the small lobe of Comet 67P/Churyumov-Gerasimenko, the OSIRIS narrow-angle camera captured this photo from 3.6 miles (5.8 km) up. We see dust-covered terrains, exposed walls and a few boulders on Ma’at, not far from the target impact region, which is located just below the lower edge. The image measures 738 feet (225 meters) across.
Comet from 5.7 km. Rosetta’s OSIRIS narrow-angle camera captured this image of Comet 67P/Churyumov-Gerasimenko at 08:21 GMT during the spacecraft’s final descent on September 30, 2016. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Just a little bit lower now. This photo showing dramatic shadows was taken from 3.5 miles (5.7 km) above the surface of the comet at 4:21 a.m. EDT Friday morning September 30.
It looks like the probe's headed for the abyss! This photo was made at 6:14 a.m. just minutes before impact from 3/4 mile (1.2 km) high. The scene measures just 33 meters across.
Headed for the abyss? This photo was made at 6:14 a.m. from 3/4 mile (1.2 km) high just a few minutes before impact. The scene measures just 108 feet (33 meters) wide.
This is Rosetta's last image of Comet 67P/Churyumov-Gerasimenko, taken shortly before impact, an estimated 51 m above the surface.
This is Rosetta’s final image of Comet 67P/Churyumov-Gerasimenko, taken shortly before impact, an estimated 66 feet (~20 meters) above the surface. The view is similar to looking down from atop a three-story building. Side to side, the photo depicts an area only 7.8 feet (2.4 meters) across. The image is soft because Rosetta’s cameras weren’t designed to photograph the comet from this close.
Sad to see its signal fade. Going... going... gone! A sequence of screenshots showing the signal from Rosetta seen at ESA's ESOC mission control centre via NASA's 70m tracking station at Madrid during comet landing on 30 September 2016. The peak of the spectrum analyser is strong at 12:19 CEST, and a few moments later, it's gone. Credit: ESA
Sad to see its signal fade. A sequence of screenshots taken at ESA’s ESOC mission control show the signal from Rosetta fading moments before impact. The peak of the spectrum analyser is strong at 6:19 EDT, and a few moments later, it’s gone. At impact, Rosetta’s was shut down and no further communication will or can be made with the spacecraft. It will continue to rest on the comet for well-nigh eternity until 67P vaporizes and crumbles apart. Credit: ESA

Bye, Bye Rosetta — We’ll Miss You!

Activity increases substantially at Comet 67P/Churyumov-Gerasimenko between Jan. 31 and March 25, 2015, when this series of pictures was taken by the Rosetta spacecraft. Credit: NAVCAM_CC-BY_SA-IGO-3.0
This montage of photos of Comet 67P/Churyumov-Gerasimenko was taken by ESA’s Rosetta spacecraft between Jan. 31 and March 25, 2015 and shows increasing activity as the comet approached perihelion. Credit: NAVCAM /CC-BY-SA-IGO-3.0

Rosetta awoke from a decade of deep-space hibernation in January 2014 and immediately got to work photographing, measuring and sampling comet 67P/C-G. On September 30 it will sleep again but this time for eternity. Mission controllers will direct the probe to impact the comet’s dusty-icy nucleus within 20 minutes of 10:40 Greenwich Time (6:40 a.m. EDT) that Friday morning. The high-resolution OSIRIS camera will be snapping pictures on the way down, but once impact occurs, it’s game over, lights out. Rosetta will power down and go silent.

A simplified overview of Rosetta’s last week of manoeuvres at Comet 67P/Churyumov–Gerasimenko (comet rotation is not considered). After 24 September the spacecraft will leave the flyover orbits and transfer towards an initial point of a 16 x 23 km orbit that will be used to prepare for the final descent. The collision course manoeuvre will take place in the evening of 29 September, initiating the descent from an altitude of about 20 km. The impact is expected to occur at 10:40 GMT (±20 minutes) at the comet, which taking into account the 40 minute signal travel time between Rosetta and Earth on 30 September, means the confirmation would be expected at mission control at 11:20 GMT / 13:20 CEST (±20 minutes).
A simplified overview of Rosetta’s last week of maneuvers at Comet 67P/Churyumov–Gerasimenko. Starting today (Sept. 24) the spacecraft will leave the flyover orbits and transfer towards a 16 x 23 km orbit that will be used to prepare for the final descent. The collision course maneuver will take place in the evening Sept. 29 with impact expected to occur at 10:40 GMT (6:40 a.m. EDT), which taking into account the 40 minute signal travel time between Rosetta and Earth on Sept. 30, means the confirmation would be expected at mission control at 11:20 GMT (7:20 a.m. EDT). Copyright: ESA

Nearly three years have passed since Rosetta opened its eyes on 67P, this curious, bi-lobed rubber duck of a comet just 2.5 miles (4 km) across with landscapes ranging from dust dunes to craggy peaks to enigmatic ‘goosebumps’. The mission was the first to orbit a comet and dispatch a probe, Philae, to its surface. I think it’s safe to say we learned more about what makes comets tick during Rosetta’s sojourn than in any previous mission.

So why end it? One of the big reasons is power. As Rosetta races farther and farther from the Sun, less sunlight falls on its pair of 16-meter-long solar arrays. At mid-month, the probe was over 348 million miles (560 million km) from the Sun and 433 million miles (697 million km) from Earth or nearly as far as Jupiter. With Sun-to-Rosetta mileage increasing nearly 620,000 miles (1 million km) a day, weakening sunlight can’t provide the power needed to keep the instruments running.


Rosetta’s last orbits around the comet

Rosetta’s also showing signs of age after having been in the harsh environment of interplanetary space for more than 12 years, two of them next door to a dust-spitting comet. Both factors contributed to the decision to end the mission rather than put the probe back into an even longer hibernation until the comet’s next perihelion many years away.

Since August 9, Rosetta has been swinging past the comet in a series of ever-tightening loops, providing excellent opportunities for close-up science observations. On September 5, Rosetta swooped within 1.2 miles (1.9 km) of 67P/C-G’s surface. It was hoped the spacecraft would descend as low as a kilometer during one of the later orbits as scientists worked to glean as much as possible before the show ends.

Rosetta will land somewhere within this planned impact ellipse in the Ma'at region on the comet's smaller lobe. Copyright: ESA
Rosetta is targeted to land at the site within this planned impact ellipse in the Ma’at region on the comet’s smaller lobe. See below for a closer view. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

The final of 15 close flyovers will be completed today (Sept. 24) after which Rosetta will be maneuvered from its current elliptical orbit onto a trajectory that will eventually take it down to the comet’s surface on Sept. 30.

The beginning of the end unfolds on the evening of the 29th when Rosetta spends 14 hours free-falling slowly towards the comet from an altitude of 12.4 miles (20 km) — about 4 miles higher than a typical commercial jet — all the while collecting measurements and photos that will be returned to Earth before impact. The last eye-popping images will be taken from a distance of just tens to a hundred meters away.

The landing will be a soft one, with the spacecraft touching down at walking speed. Like Philae before it, it will probably bounce around before settling into place. Mission control expects parts of the probe to break upon impact.

Taking into account the additional 40 minute signal travel time between Rosetta and Earth on the 30th, confirmation of impact is expected at ESA’s mission control in Darmstadt, Germany, within 20 minutes of 11:20 GMT (7:20 a.m. EDT). The times will be updated as the trajectory is refined. You can watch live coverage of Rosetta’s final hours on ESA TV .


ESAHangout: Preparing for Rosetta’s grand finale

“It’s hard to believe that Rosetta’s incredible 12.5 year odyssey is almost over, and we’re planning the final set of science operations, but we are certainly looking forward to focusing on analyzing the reams of data for many decades to come,” said Matt Taylor, ESA’s Rosetta project scientist.

The spacecraft will aim at a point just right of the image centre, next to Deir el-Medina, the large pit located slightly below and to the right of centre in this view. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0
The spacecraft landing site is shown in red and located next to Deir el-Medina, a large pit (arrowed). Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Plans call for the spacecraft to impact the comet somewhere within an ellipse about 1,300 x 2,000 feet (600 x 400 meters) long on 67P’s smaller lobe in the region known as Ma’at. It’s home to several active pits more than 328 feet (100 meters) in diameter and 160-200 feet (50-60 meters) deep, where a number of the comet’s dust jets originate. The walls of the pits are lined with fascinating meter-sized lumpy structures called ‘goosebumps’, which scientists believe could be early ‘cometesimals’, the icy snowballs that stuck together to create the comet in the early days of our Solar System’s formation.

Close-up of a curious surface texture nicknamed ‘goosebumps’. The characteristic scale of all the bumps seen on Comet 67P/Churyumov–Gerasimenko by the OSIRIS narrow-angle camera is approximately 3 m, extending over regions greater than 100 m. They are seen on very steep slopes and on exposed cliff faces, but their formation mechanism is yet to be explained. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Close-up of a curious surface texture nicknamed ‘goosebumps’. The bumps are about 9 feet (3 meters) across and seen on very steep slopes and exposed cliff faces. They may represent the original balls of icy dust that glommed together to form comets 4.5 billion years ago. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

During free-fall, the spacecraft will target a point adjacent to a 425-foot (130 m) wide, well-defined pit that the mission team has informally named Deir el-Medina, after a structure with a similar appearance in an ancient Egyptian town of the same name. High resolution images should give us a spectacular view of these enigmatic bumps.

While we hate to see Rosetta’s mission end, it’s been a blast going for a 2-year-plus comet ride-along.

Weekly Space Hangout – Sept 23, 2016: Dr. Frank Timmes and Online Astronomy Education

Host: Fraser Cain (@fcain)

Special Guests:
Dr. Frank Timmes is an astrophysicist at Arizona State University and will be discussing online astronomy education and the Global Freshman Academy. His interests include the universe’s evolving composition and its implications for life in the universe. Dr. Timmes’ current area of research is nuclear astrophysics and the creation of the periodic table.

Guests:

Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg)
Dave Dickinson (www.astroguyz.com / @astroguyz)
Kimberly Cartier ( KimberlyCartier.org / @AstroKimCartier )
Nicole Gugliucci (cosmoquest.org / @noisyastronomer)

Their stories this week:

New bill targets serial harasses

Tiangong-1 to crash next year

The Final Days of Rosetta

Microlensing circumbinary planet detected

Repeat of Voyager’s “impossible” cloud

We are now using a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!

We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page.

There It Is! Philae Lander Found

The search is over, and looking at these images, no wonder it was so hard to find the little Philae lander!

The high-resolution camera on board the Rosetta spacecraft has finally spotted Philae “wedged into a dark crack on Comet 67P/Churyumov-Gerasimenko,” the ESA team said. They also said that now, seeing the lander’s orientation, it’s clear why establishing communications was so difficult following its landing on November 12, 2014.

Close-up of the Philae lander.  Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Close-up of the Philae lander. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta, orbiting the comet and getting ready for its own demise/touchdown on 67P, focused its OSIRIS narrow-angle camera towards a few candidate sites on September 2, 2016 as the orbiter came just 2.7 km of the comet’s surface. Clearly visible in the zoomed in versions are the main body of the lander, along with two of its three legs.

“With only a month left of the Rosetta mission, we are so happy to have finally imaged Philae, and to see it in such amazing detail,” says Cecilia Tubiana of the OSIRIS camera team, the first person to see the images when they were downlinked from Rosetta on September 4.

Tubiana told Universe Today via email that Philae wasn’t too hard to find in the images. “Philae was in hiding in shadow, and as soon as we stretched the brightness to ‘see’ into the shadow, Philae was there!”

She added that nothing else about Philae’s condition has been revealed from the images so far.

The Philae lander was last seen after it first touched down at a region called Agilkia on the odd-shaped, two-lobed comet 67P. During its dramatic touchdown, the lander flew, landed, bounced and then repeated that process for more than two hours across the surface, with three or maybe four touchdowns. The harpoons that were to anchor Philae to the surface failed to fire, and scientists estimated the lander may have bounced as high as 3.2 kilometers (2 miles) before becoming wedged in the shadows of a cliff on the comet. After three days, Philae’s primary battery ran out of power and the lander went into hibernation, only to wake up again and communicate briefly with Rosetta in June and July 2015 as the comet came closer to the Sun and more power was available.

But after more than a year of silence, the Rosetta team announced in mid-August 2016 that they would no longer attempt communications with Philae.

Philae’s final location had been plotted but until yesterday, never actually seen by Rosetta’s cameras. Radio ranging data was used to narrow down the search to an area spanning a few tens of meters, and a number of potential candidate objects were identified in relatively low-resolution images taken from larger distances.

Philae close-up, labelled. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
Philae close-up, labelled. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

Compare some of the features of the cliff in the image above to this image taken by Philae of its surroundings:

The Philae lander captured a picture of a nearby cliff, nicknamed “Perihelion Cliff”, on the nucleus of Comet 67P/Churyumov-Gerasimenko. Credit: ESA/Rosetta/Philae/CIVA.
The Philae lander captured a picture of a nearby cliff, nicknamed “Perihelion Cliff”, on the nucleus of Comet 67P/Churyumov-Gerasimenko. Credit: ESA/Rosetta/Philae/CIVA.

“After months of work, with the focus and the evidence pointing more and more to this lander candidate, I’m very excited and thrilled that we finally have this all-important picture of Philae sitting in Abydos,” said ESA’s Laurence O’Rourke, who has been coordinating the search efforts over the last months at ESA, with the OSIRIS and SONC/CNES teams.

At 2.7 km, the resolution of the OSIRIS narrow-angle camera is about 5 cm/pixel, which is sufficient to reveal features of Philae’s 1 m-sized body and its legs.

“This wonderful news means that we now have the missing ‘ground-truth’ information needed to put Philae’s three days of science into proper context, now that we know where that ground actually is!” says Matt Taylor, ESA’s Rosetta project scientist.

An OSIRIS narrow-angle camera image taken on 2 September 2016 from a distance of 2.7 km in which Philae was definitively identified. The image has been processed to adjust the dynamic range in order to see Philae while maintaining the details of the comet's surface. Philae is located at the far right of the image, just above center. The image scale is about 5 cm/pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
An OSIRIS narrow-angle camera image taken on 2 September 2016 from a distance of 2.7 km in which Philae was definitively identified. The image has been processed to adjust the dynamic range in order to see Philae while maintaining the details of the comet’s surface. Philae is located at the far right of the image, just above center. The image scale is about 5 cm/pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

The discovery comes less than a month before Rosetta descends to the comet’s surface. On September 30, the orbiter will be sent on a final one-way mission to investigate the comet from close up, including the open pits in a region called Ma’at, where it is hoped that critical observations will help to reveal secrets of the body’s interior structure.

“Now that the lander search is finished we feel ready for Rosetta’s landing, and look forward to capturing even closer images of Rosetta’s touchdown site,” adds Holger Sierks, principal investigator of the OSIRIS camera.

The Rosetta team said they would be providing more details about the search as well as more images in the near future.

Source: ESA

Rosetta’s Philae Lander in Permanent Sleep

NAVCAM image of comet 67P/Churyumov-Gerasimenko acquired on Nov. 22, 2015.
NAVCAM image of comet 67P/Churyumov-Gerasimenko acquired on Nov. 22, 2015. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.

ESA’s Philae lander, the first spacecraft to successfully soft-land on the surface of a comet and former piggyback partner to Rosetta, has not been in communication since July of 2015 and, with 67P now six months past perihelion and heading deeper out into the Solar System, it’s not likely it will ever be heard from again.

Continue reading “Rosetta’s Philae Lander in Permanent Sleep”

Weekly Space Hangout – Feb. 5, 2016: Dr. Or Graur

Host: Fraser Cain (@fcain)

Special Guest: Dr. Or Graur, Research Associate at the Center for Cosmology and Particle Physics at New York University; Researches what type of star leads to a thermonuclear, or “Type Ia,” supernova.

Guests:
Carolyn Collins Petersen (thespacewriter.com / space.about.com / @spacewriter )
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Jolene Creighton (fromquarkstoquasars.com / @futurism)
Alessondra Springmann (@sondy)

Continue reading “Weekly Space Hangout – Feb. 5, 2016: Dr. Or Graur”

How to Find Rosetta’s Comet In Your Telescope

How would you like to see one of the most famous comets with your own eyes? Comet 67P/Churyumov-Gerasimenko plies the morning sky, a little blot of fuzzy light toting an amazing visitor along for the ride — the Rosetta spacecraft. When you look at the coma and realize a human-made machine is buzzing around inside, it seems unbelievable. 

Comet 67P/Churyumov-Gerasimenko plows through a rich star field in Gemini on the morning of August 19, 2015. Photos show a short, faint tail to the west not visible to the eye in most amateur telescopes. Credit: Efrain Morales
Comet 67P/Churyumov-Gerasimenko plows through a rich star field in Gemini on the morning of August 20, 2015. Photos show a short, faint tail to the west not visible to the eye in most amateur telescopes. Credit: Efrain Morales

If you have a 10-inch or larger telescope, or you’re an experienced amateur with an 8-inch and pristine skies, 67P is within your grasp. The comet glows right around magnitude +12, about as bright as it will get this apparition. Periodic comets generally appear brightest around and shortly after perihelion or closest approach to the Sun, which for 67P/C-G occurred back on August 13.

The surface of Comet 67P/C-G is extensively fractured likely related to the intense freeze-thaw cycle that occurs during the heat of perihelion vs. the chill experienced in the outer part of its orbit. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
The surface of Comet 67P/C-G is extensively fractured due to loss of volatile ices, the expansion and contraction of the comet from solar heating and bitter cold and possibly even tectonic forces. The smaller polygonal shapes outlined by fractures in the lower right photo are just 6-16 feet (2-5 meters) across. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

You’ll be looking for a small, 1-arc-minute-diameter, compact, circular patch of nebulous light shortly before dawn when it’s highest in the east. Rosetta’s Comet will spend the remainder of August slicing across Gemini the Twins north of an nearly parallel to the ecliptic. I spotted 67P/C-G for the first time this go-round about a week ago in my 15-inch (37 cm) reflector. While it appears like a typical faint comet, thanks to Rosetta, we know this particular rough and tumble mountain of ice better than any previous comet. Photographs show rugged cliffs, numerous cracks due to the expansion and contraction of ice, blowholes that serve as sources for jets and smooth plains blanketed in fallen dust.

Geysers of dust and gas shooting off the comet's nucleus are called jets. The material they deliver outside the nucleus builds the comet's coma. Credit: ESA/Rostta/NAVCAM
Geysers of dust and gas shooting off the comet’s nucleus are called jets. The material they deliver outside the nucleus builds the comet’s coma. Credit: ESA/Rostta/NAVCAM

The jets are geyser-like sprays of dust and gas that loft grit and rocks from the comet’s interior and surface into space to create a coma or temporary atmosphere. This is what you’ll see in your telescope. And if you’re patient, you’ll even be able to catch this glowing tadpole on the move. I was surprised at its speed. After just 20 minutes, thanks to numerous field stars that acted as references, I could easily spot the comet’s eastward movement using a magnification of 245x.

Facing east around 4 a.m. local time in late August, you'll see the winter constellations Gemini and Orion. 67P/C-G's path is shown through
Facing east around 4 a.m. local time in late August, you’ll see the winter constellations Gemini and Orion. 67P/C-G’s path is shown through early September. Brighter stars near the path are labeled. Time shown is 4 a.m. CDT. Use this map to get oriented and then switch to the one below for telescope use. Source: Chris Marriott’s SkyMap

Tomorrow morning, 67P/C-G passes very close to the magnitude +5 star Omega Geminorum. While this will make it easy to locate, the glare may swamp the comet. Set your alarm for an hour before dawn’s start to allow time to set up a telescope, dark-adapt your eyes and track down the field where the comet will be that morning using low magnification.

Once you’ve centered 67P/C-G’s position, increase the power to around 100x-150x and use averted vision to look for a soft, fuzzy patch of light. If you see nothing, take it to the next level (around 200-250x) and carefully search the area. The higher the magnification, the darker the field of view and easier it will be to spot it.

Detailed map showing the comet's path through central Gemini daily August 21-28, 2015 around 4 a.m. CDT. Brighter stars are marked with Greek letters and numbers. "48" = 48 Geminorum. Source: Chris Marriott's SkyMap
Detailed map showing the comet’s path through central Gemini daily August 21-28, 2015 around 4 a.m. CDT. Brighter stars are marked with Greek letters and numbers. “57”= 57 Geminorum. North is up, east to the left and stars to magnitude +13.5. Click for a larger version you can print out. Source: Chris Marriott’s SkyMap

Besides being relatively faint, the comet doesn’t get very high in the east before the onset of twilight. Low altitude means the atmosphere absorbs a share of the comet’s light, making it appear even fainter. Not that I want to dissuade you from looking! There’s nothing like seeing real 67P photons not to mention the adventure and sense of accomplishment that come from finding the object on your own.

As we advance into late summer and early fall, 67P/C-G will appear higher up but also be fading. Now through about August 27 and again from September 10-24 will be your best viewing times. That’s when the Moon’s absent from the sky.

Given the comet’s current distance from Earth of 165 million miles and apparent visual size of just shy of 1 arc minute, the coma measures very approximately 30,000 miles across. Rosetta orbits the comet’s 2.5-mile-long icy nucleus at a distance of about 115 miles (186 km), meaning it’s snug up against the nuclear center from our point of view on the ground.

If you do find and follow 67P/C-G, consider sharing your observations with the Pro-Amateur Collaborative Astronomy (PACA) campaign to help increase our knowledge of its behavior. Interested? Sign up HERE.

More Evidence That Comets May Have Brought Life to Earth

The idea of panspermia — that life on Earth originated from comets or asteroids bombarding our planet — is not new. But new research may have given the theory a boost. Scientists from Japan say their experiments show that early comet impacts could have caused amino acids to change into peptides, becoming the first building blocks of life. Not only would this help explain the genesis of life on Earth, but it could also have implications for life on other worlds.

Dr. Haruna Sugahara, from the Japan Agency for Marine-Earth Science and Technology in Yokahama, and Dr. Koichi Mimura, from Nagoya University said they conducted “shock experiments on frozen mixtures of amino acid, water ice and silicate (forsterite) at cryogenic condition (77 K),” according to their paper. “In the experiments, the frozen amino acid mixture was sealed into a capsule … a vertical propellant gun was used to [simulate] impact shock.”

They analyzed the post-impact mixture with gas chromatography, and found that some of the amino acids had joined into short peptides of up to 3 units long (tripeptides).

Based on the experimental data, the researchers were able to estimate that the amount of peptides produced would be around the same as had been thought to be produced by normal terrestrial processes (such as lighting storms or hydration and dehydration cycles).

Artists concept of the stardust spacecraft flying throug the gas and dust from comet Wild 2. Credit: NASA/JPL
Artists concept of the stardust spacecraft flying throug the gas and dust from comet Wild 2. Credit: NASA/JPL
“This finding indicates that comet impacts almost certainly played an important role in delivering the seeds of life to the early Earth,” said Sugahara. “It also opens the likelihood that we will have seen similar chemical evolution in other extraterrestrial bodies, starting with cometary-derived peptides.”

The earliest known fossils on Earth are from about 3.5 billion years ago and there is evidence that biological activity took place even earlier. But there’s evidence that early Earth had little water and carbon-based molecules on the Earth’s surface, so how could these building blocks of life delivered to the Earth’s surface so quickly? This was also about the time of the Late Heavy Bombardment, and so the obvious answer could be the collision of comets and asteroids with the Earth, since these objects contain abundant supplies of both water and carbon-based molecules.

A view of NASA's Deep Impact probe colliding with comet Tempel 1, captured by the Deep Impact flyby spacecraft's high-resolution instrument.
A view of NASA’s Deep Impact probe colliding with comet Tempel 1, captured by the Deep Impact flyby spacecraft’s high-resolution instrument.

Space missions to comets are helping to confirm this possibility. The 2004 Stardust mission found the amino acid when it collected particles from Comet Wild 2. When NASA’s Deep Impact spacecraft crashed into Comet Tempel 1 in 2005, it discovered a mixture of organic and clay particles inside the comet. One theory about the origins of life is that clay particles act as a catalyst, allowing simple organic molecules to get arranged into more and more complex structures.

The news from the current Rosetta mission to comet 67P/Churyumov-Gerasimenko also indicates that comets are a rich source of materials, and more discoveries are likely to be forthcoming from that mission.

Jets of gas and dust are blasting from the active neck of comet 67P/Churyumov-Gerasimenko in this photo mosaic assembled from four images taken on 26 September 2014 by the European Space Agency’s Rosetta spacecraft at a distance of 26.3 kilometers (16 miles) from the center of the comet. Credit: ESA/Rosetta/NAVCAM/Marco Di Lorenzo/Ken Kremer/kenkremer.com
Jets of gas and dust are blasting from the active neck of comet 67P/Churyumov-Gerasimenko in this photo mosaic assembled from four images taken on 26 September 2014 by the European Space Agency’s Rosetta spacecraft at a distance of 26.3 kilometers (16 miles) from the center of the comet. Credit: ESA/Rosetta/NAVCAM/Marco Di Lorenzo/Ken Kremer/kenkremer.com

“Two key parts to this story are how complex molecules are initially generated on comets and then how they survive/evolve when the comet hits a planet like the Earth,” said Professor Mark Burchell from the University of Kent in the UK, commenting on the new research from Japan. “Both of these steps can involve shocks which deliver energy to the icy body… building on earlier work, Dr. Sugahara and Dr. Mimura have shown how amino acids on icy bodies can be turned into short peptide sequences, another key step along the path to life.”

“Comet impacts are normally associated with mass extinction on Earth, but this works shows that they probably helped kick-start the whole process of life in the first place,” said Sugahara. “The production of short peptides is the key step in the chemical evolution of complex molecules. Once the process is kick-started, then much less energy is needed to make longer chain peptides in a terrestrial, aquatic environment.”

The scientists also indicated that similar “kickstarting” could have happened in other places in our Solar System, such as on the icy moons Europa and Enceladus, as they likely underwent a similar comet bombardment.

Sugahara and Mimura presented their findings at the Goldschmidt geochemistry conference in Prague, going on this week.

Spectacular Celestial Fireworks Commemorate Perihelion Passage of Rosetta’s Comet

Sequence of OSIRIS narrow-angle camera images from 12 August 2015, just a few hours before the comet reached perihelion. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
See hi res images below[/caption]

A spectacular display of celestial fireworks like none ever witnessed before, burst forth from Rosetta’s comet right on time – commemorating the Europeans spacecraft’s history making perihelion passage after a year long wait of mounting excitement and breathtaking science.

As the European Space Agency’s (ESA’s) Rosetta marked its closest approach to the Sun (perihelion) at exactly 02:03 GMT on Thursday, August 13, 2015, while orbiting Comet 67P/Churyumov–Gerasimenko, its suite of 11 state-of-the-art science instruments, cameras and spectrometers were trained on the utterly bizarre bi-lobed body to capture every facet of the comet’s nature and environment for analysis by the gushing science teams.

And the perihelion passage did not disappoint – living up to its advance billing by spewing forth an unmatched display of otherworldly outbursts of gas jets and dust particles due to surface heating from the warming effects of the sun as the comet edged ever closer, coming within 186 million kilometers of mighty Sol.

ESA has released a brand new series of images, shown above and below, documenting sparks flying – as seen by Rosetta’s OSIRIS narrow-angle camera and NAVCAM wider angle cameras on August 12 and 13 – just a few hours before the rubby ducky shaped comet reached perihelion along its 6.5-year orbit around the sun.

Images of Comet 67P/C-G taken with OSIRIS narrow-angle camera on 12 August 2015, just a few hours before the comet reached perihelion, about 330 km from the comet. The individual images are also available below. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Images of Comet 67P/C-G taken with OSIRIS narrow-angle camera on 12 August 2015, just a few hours before the comet reached perihelion, about 330 km from the comet. The individual images are also available below. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Indeed the navcam camera image below was taken just an hour before the moment of perihelion, at 01:04 GMT, from a distance of around 327 kilometers!

Frozen ices are seen blasting away from the comet in a hail of gas and dust particles as rising solar radiation heats the nucleus and fortifies the comet’s atmosphere, or coma, and its tail.

Comet at perihelion.  Single frame Rosetta navigation camera image acquired at 01:04 GMT on 13 August 2015, just one hour before Comet 67P/Churyumov–Gerasimenko reached perihelion – the closest point to the Sun along its 6.5-year orbit. The image was taken around 327 km from the comet. It has a resolution of 28 m/pixel, measures 28.6 km across and was processed to bring out the details of the comet's activity. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0
Comet at perihelion. Single frame Rosetta navigation camera image acquired at 01:04 GMT on 13 August 2015, just one hour before Comet 67P/Churyumov–Gerasimenko reached perihelion – the closest point to the Sun along its 6.5-year orbit. The image was taken around 327 km from the comet. It has a resolution of 28 m/pixel, measures 28.6 km across and was processed to bring out the details of the comet’s activity. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

After a decade long chase of over 6.4 billion kilometers (4 Billion miles), ESA’s Rosetta spacecraft arrived at the pockmarked Comet 67P/Churyumov-Gerasimenko exactly a year ago on Aug. 6, 2014 for history’s first ever attempt to orbit a comet for long term study.

In the interim, Rosetta also deployed the piggybacked Philae lander for history’s first landing on a comet on Nov. 12, 2014.

In fact, measurements from Rosetta’s science instruments confirm the comet is belching a thousand times more water vapor today than was observed during Rosetta’s arrival a year ago. It’s spewing some 300 kg of water vapour every second now, compared to just 300 g per second upon arrival. That equates to two bathtubs per second now in Aug. 2015 vs. two small glasses of water per second in Aug. 2014.

Besides gas, 1000 kg of dust per second is simultaneously erupting from the nucleus, “creating dangerous working conditions for Rosetta,” says ESA.

“In recent days, we have been forced to move even further away from the comet. We’re currently at a distance of between 325 km and 340 km this week, in a region where Rosetta’s startrackers can operate without being confused by excessive dust levels – without them working properly, Rosetta can’t position itself in space,” comments Sylvain Lodiot, ESA’s spacecraft operations manager, in an ESA statement.

Here’s an OSIRIS image taken just hours prior to perihelion, that’s included in the lead animation of this story.

OSIRIS NAC image of Comet 67P/C-G taken on 12 August 2015 at 17:35 GMT. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
OSIRIS NAC image of Comet 67P/C-G taken on 12 August 2015 at 17:35 GMT. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The period of the comet’s peak intensity, as seen in all these images, is expected to continue past perihelion for several weeks at least and fulfils the dreams of a scientific goldmine for all the research teams and hundreds of researchers involved with Rosetta and Philae.

“Activity will remain high like this for many weeks, and we’re certainly looking forward to seeing how many more jets and outburst events we catch in the act, as we have already witnessed in the last few weeks,” says Nicolas Altobelli, acting Rosetta project scientist.

And Rosetta still has lots of fuel, and just as important – funding – to plus up its ground breaking science discoveries.

ESA recently granted Rosetta a 9 month mission extension to continue its research activities as well as having been given the chance to accomplish one final and daring historic challenge.

Engineers will attempt to boldly go and land the probe on the undulating surface of the comet.

Officials with the European Space Agency (ESA) gave the “GO” on June 23 saying “The adventure continues” for Rosetta to march forward with mission operations until the end of September 2016.

If all continues to go well “the spacecraft will most likely be landed on the surface of Comet 67P/Churyumov-Gerasimenko” said ESA.

ESA Philae lander approaches comet 67P/Churyumov–Gerasimenko on 12 November 2014 as imaged from Rosetta orbiter after deployment and during seven hour long approach for 1st ever  touchdown on a comets surface.  Credit:  ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA - Composition by Marco Di Lorenzo/Ken Kremer
ESA Philae lander approaches comet 67P/Churyumov–Gerasimenko on 12 November 2014 as imaged from Rosetta orbiter after deployment and during seven hour long approach for 1st ever touchdown on a comets surface. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA – Composition by Marco Di Lorenzo/Ken Kremer

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

Jets of gas and dust are blasting from the active neck of comet 67P/Churyumov-Gerasimenko in this photo mosaic assembled from four images taken on 26 September 2014 by the European Space Agency’s Rosetta spacecraft at a distance of 26.3 kilometers (16 miles) from the center of the comet. Credit: ESA/Rosetta/NAVCAM/Marco Di Lorenzo/Ken Kremer/kenkremer.com
Jets of gas and dust are blasting from the active neck of comet 67P/Churyumov-Gerasimenko in this photo mosaic assembled from four images taken on 26 September 2014 by the European Space Agency’s Rosetta spacecraft at a distance of 26.3 kilometers (16 miles) from the center of the comet. Credit: ESA/Rosetta/NAVCAM/Marco Di Lorenzo/Ken Kremer/kenkremer.com

Why is it Tough to Land on a Comet?

Why is landing on a comet so difficult and what does this tell us about future missions to comets and asteroids?

Us nerds were riveted by the coverage of the ESA’s Rosetta mission and its arrival at Comet 67/P in 2014. One such nerd is Paco Juarez, friend of the show and patron. He wanted to know why is it so darned hard to land on a comet?

In 2014, the tiny Philae Lander detached from the spacecraft and slowly descended down to the surface of the comet. If everything went well, it would have gracefully touched down and then sent back a pile of information about this filthy roving snowball.
As you know, the landing didn’t go according to plan. Instead of gently touching down on 67/P, Philae bounced off the surface of the comet like a tennis ball dropped from a tower, and rose a kilometer off the surface. Then more descending, and more bouncing, finally settling down on rugged terrain, surrounded by crevices and large boulders. At that point, engineers lost contact with the lander, and so much science went undone.

If I recorded this video a few months ago, that would have been the end of the story. You know how this goes, space exploration is hard and dangerous, don’t be surprised when your missions fail and space unfeelingly smashes up your pretty little robot probes with their little gold foil 27 pieces of flair.

Rosetta
Rosetta

Fortunately, I’m able to report that ESA regained contact with the Philae lander on June 13, 2015, resuming its mission, and scientific operations.

But why is landing on a comet so difficult and what does this tell us about future robotic and human missions to smaller comets and asteroids? When ESA engineers designed Philae, they knew it was going to be very difficult to land on a comet like 67/P because they have a such a low gravity. And they have low gravity because they’re little.

Illustration of the Rosetta Missions Philae lander on final approach to a comet surface. (Photo: ESA)
Illustration of the Rosetta Missions Philae lander on final approach to a comet surface. (Photo: ESA)

On Earth, 6 septillion tonnes of rock and metal give you an escape velocity of 11.2 km/s. That’s how fast you need to be able to jump in order to leave the planet entirely. But the escape velocity of 67/P is only 1 m/s. You could trip off the comet and never return. Whilst small children threw rocks at you from the surface as you drifted away.

Philae was built with harpoon drills in its landing struts. The moment the lander touched the surface of the comet, those harpoons were supposed to fire, securing the lander. The surface of the comet was softer than scientists had anticipated, and the harpoons didn’t fire. Or possibly they were broken and couldn’t fire. Space is hard. Whatever the case, without being able to grab onto the surface, it used the comet as a bouncy castle.

We’re learning what it takes to land on lower mass objects like comets and asteroids. NASA’s OSIRIS-REx mission will visit Comet Bennu, and send a lander down to the surface of the asteroid. From there it’ll pick up a few samples, and return them back to Earth. It’ll be Philae, all over again.

An artist concept of the Philae lander on comet 67P/Churyumov-Gerasimenko.  Credit: Astrium - E. Viktor/ESA
An artist concept of the Philae lander on comet 67P/Churyumov-Gerasimenko. Credit: Astrium – E. Viktor/ESA

In the future, we’re told, humans will be visiting asteroids to study them for science and their potential for ice and minerals. You can imagine it’ll be a harrowing descent, but even just walking around on the surface will be dangerous when every step could throw an astronaut into an escape trajectory. They’ll need to learn lessons from rock climbers and Rorschach.

As we learned with Philae, landings on low mass objects is really tough. We’re going to need to get more practice and develop new techniques and technologies before we’re ready to add asteroid mining to our list of “stuff we just do, NBD”.

What are some unusual worlds you’d like humanity to visit? Put your suggestions in the comments below.