Comet 2013 A1 Siding Spring on October 17, 2014, with two days to go until its Martian encounter. Very dense Milkyway starfield in the background with many darker obscured regions. Credit and copyright: Damian Peach.
The excitement continues to build as Comet Siding Spring rapidly approaches the Red Planet, and here’s the latest view of the comet from prolific astrophotographer Damian Peach. While Comet Siding Spring’s encounter with Mars on October 19 will not be visible from Earth with the unaided eye, skywatchers in mid-northern latitudes, can now view the comet; an 8-inch (20 cm) or larger telescopes is needed to follow the comet as it travels from Scorpius north to Ophiuchus and its encounter with Mars on October 19.
The comet will come within 139,500 km (86,000 miles) above the planet’s surface on Sunday.
As our David Dickinson discussed earlier this week, if you were an astronaut stranded on the surface of Mars, the comet’s passage would be a spectacular sight under the dark Martian sky. Some scientists suggest it could even spawn a short but brilliant meteor shower caused by cometary dust grains plunging into the Martian atmosphere.
The spacecraft in orbit around Mars will be watching Comet Siding Spring too. The fleet of spacecraft from ESA, NASA and ISRO will hide behind the Red Planet on Sunday morning, trying to avoid possible bombardment by tiny grains of dust from the comet. But before and after that, the spacecraft will attempt to gather data on the comet as well as try to measure how the gas and dust interact with the Martian atmosphere.
Stay tuned for news on the comet’s encounter with Mars.
Context image showing the location of the primary landing site for Rosetta’s lander Philae. Site J is located on the head of Comet 67P/Churyumov–Gerasimenko. An inset showing a close up of the landing site is also shown. The inset image was taken by Rosetta’s OSIRIS narrow-angle camera on 20 August 2014 from a distance of about 67 km. The image scale is 1.2 metres/pixel. The background image was taken on 16 August from a distance of about 100 km. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Scientists leading the European Space Agency’s Rosetta mission announced the primary landing site at a media briefing today, Sept. 15, at ESA headquarters.
After weeks of detailed study and debate focused on balancing scientific interest with finding a ‘technically feasible’ and safe Philae touchdown site, the team chose a target dubbed Site J as the primary landing site from among a list of five initially selected sites, said Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center, at the briefing.
“Site J is the primary landing site around the head of the comet,” Ulamec announced.
“Site C is the backup site on the body [near the bottom of the comet].”
“This was not an easy task. Site J is a mix of flat areas and rough terrain. It’s not a perfectly flat area. There is still risk with high slope areas.”
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
He also made clear that there is still some landing uncertainty with the targeting of the lander onto the comet.
Site J is an intriguing region on Comet 67P/Churyumov–Gerasimenko that offers unique scientific potential, with hints of activity nearby, and minimum risk to the lander compared to the other candidate sites, according to ESA.
“As we have seen from recent close-up images, the comet is a beautiful but dramatic world – it is scientifically exciting, but its shape makes it operationally challenging,” says Ulamec.
“None of the candidate landing sites met all of the operational criteria at the 100% level, but Site J is clearly the best solution.”
Philae’s history-making landing on comet 67P is currently scheduled for around Nov. 11, 2014, and will be entirely automatic. The 100 kg lander is equipped with 10 science instruments.
“All of Rosetta’s instruments are supporting the landing site selection,” said Holger Sierks, principal investigator for Rosetta’s OSIRIS camera from the Max Planck Institute for Solar System Research in Gottingen, Germany.
“Site J is just 500-600 meters away from some pits and an area of comet outgassing activity. They will become more active as we get closer to the sun.
The team is in a race against time to select a suitable landing zone quickly and develop the complex landing sequence since the comet warms up and the surface becomes ever more active as it swings in closer to the sun and makes the landing ever more hazardous.
Since the descent to the comet is passive it is only possible to predict that the landing point will place within a ‘landing ellipse’ typically a few hundred metres in size, the team elaborated.
The three-legged lander will fire two harpoons and use ice screws to anchor itself to the 4 kilometer (2.5 mile) wide comet’s surface. Philae will collect stereo and panoramic images and also drill 20 to 30 centimeters into and sample its incredibly varied surface.
“We will make the first ever in situ analysis of a comet at this site, giving us an unparalleled insight into the composition, structure and evolution of a comet,” says Jean-Pierre Bibring, a lead lander scientist and principal investigator of the CIVA instrument at the IAS in Orsay, France.
“Site J in particular offers us the chance to analyse pristine material, characterise the properties of the nucleus, and study the processes that drive its activity.”
“It’s amazing how much we have learned so far.”
“We are in a true revolution of how we think Planets form and evolve,” Bibring elaborated at the briefing.
“We will make many types of scientific measurements of the comet from the surface. We will get a complete panoramic view of the comet on the macroscopic and microscopic scale.”
Rosetta is currently orbiting the comet from a distance of 30 km, said ESA Rosetta flight director Andrea Accomazzo. He said it will likely go even closer to 20 km and perhaps 10 km.
Four-image photo mosaic comprising images taken by Rosetta’s navigation camera on 2 September 2014 from a distance of 56 km from comet 67P/Churyumov-Gerasimenko. The mosaic has been contrast enhanced to bring out details of the coma, especially of jets of dust emanating from the neck region. Credits: ESA/Rosetta/NAVCAM/Marco Di Lorenzo/Ken Kremer – kenkremer.com
“Now that we’re closer to the comet, continued science and mapping operations will help us improve the analysis of the primary and backup landing sites,” says ESA Rosetta flight director Andrea Accomazzo.
“Of course, we cannot predict the activity of the comet between now and landing, and on landing day itself. A sudden increase in activity could affect the position of Rosetta in its orbit at the moment of deployment and in turn the exact location where Philae will land, and that’s what makes this a risky operation.”
Four-image photo mosaic comprising images taken by Rosetta’s navigation camera on 31 August 2014 from a distance of 61 km from comet 67P/Churyumov-Gerasimenko. The mosaic has been rotated and contrast enhanced to bring out details. The comet nucleus is about 4 km across. Credits: ESA/Rosetta/NAVCAM/Ken Kremer/Marco Di Lorenzo
The final landing site selections were made at a meeting being held this weekend on 13 and 14 September 2014 between the Rosetta Lander Team and the Rosetta orbiter team at CNES in Toulouse, France.
“No one has ever attempted to land on a comet before, so it is a real challenge,” says Fred Jansen, ESA Rosetta mission manager.
“The complicated ‘double’ structure of the comet has had a considerable impact on the overall risks related to landing, but they are risks worth taking to have the chance of making the first ever soft landing on a comet.”
Five candidate sites were identified on Comet 67P/Churyumov-Gerasimenko for Rosetta’s Philae lander. The approximate locations of the five regions are marked on these OSIRIS narrow-angle camera images taken on 16 August 2014 from a distance of about 100 km. Enlarged insets below highlight 5 landing zones. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Processing: Marco Di Lorenzo/Ken Kremer
Stay tuned here for Ken’s continuing Rosetta, Earth and Planetary science and human spaceflight news.
Jagged cliffs and prominent boulders are visible in this image taken by OSIRIS on 5 September 2014 from a distance of 62 kilometres from comet 67P/Churyumov-Gerasimenko. The left part of the image shows a side view of the comet’s 'body', while the right is the back of its 'head'. One pixel corresponds to 1.1 metres.
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Today ESA released the latest high resolution images of Comet 67P/Churyumov-Gerasimenko taken by the OSIRIS science camera on Sept. 5, and is shown above.
Jagged cliffs and prominent boulders are clearly visible in unprecedented detail on the head and body of Comet 67P displaying a multitude of different terrains in the new image taken from a distance of 62 kilometers.
Meanwhile the Rosetta science team is using the OSIRIS and navcam camera images to create a preliminary map of the comets surface. The map is color coded to divide the comet into several distinct morphological regions.
Several morphologically different regions are indicated in this preliminary map, which is oriented with the comet’s ‘body’ in the foreground and the ‘head’ in the background. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
“With various areas dominated by cliffs, depressions, craters, boulders or even parallel grooves, 67P/C-G displays a multitude of different terrains. Some areas even appear to have been shaped by the comet’s activity,” the Rosetta team said in the release.
The images were also shown at today’s scientific presentations at a special Rosetta research session at the 2014 European Planetary Science Congress being held in Cascais, Portugal.
The scientists are striving to meld all the imagery and data gathered from Rosetta’s 11 instruments in order to elucidate the composition and evolution of the different regions.
The mapping data is also being used to narrow the ‘Top 5’ Philae landing site candidates down to a primary and backup choice.
The final landing site selections will be made at a meeting being held this weekend on 13 and 14 September 2014 between the Rosetta Lander Team and the Rosetta orbiter team at CNES in Toulouse, France.
Four-image photo mosaic comprising images taken by Rosetta’s navigation camera on 2 September 2014 from a distance of 56 km from comet 67P/Churyumov-Gerasimenko. The mosaic has been contrast enhanced to bring out details of the coma, especially of jets of dust emanating from the neck region.
Credits: ESA/Rosetta/NAVCAM/Marco Di Lorenzo/Ken Kremer – kenkremer.com
Philae’s history making landing on comet 67P is currently scheduled for around Nov. 11, 2014, and will be entirely automatic. The 100 kg lander is equipped with 10 science instruments.
The three-legged lander will fire two harpoons and use ice screws to anchor itself to the 4 kilometer (2.5 mile) wide comet’s surface. Philae will collect stereo and panoramic images and also drill 23 centimeters into and sample its incredibly varied surface.
Four-image photo mosaic comprising images taken by Rosetta’s navigation camera on 31 August 2014 from a distance of 61 km from comet 67P/Churyumov-Gerasimenko. The mosaic has been rotated and contrast enhanced to bring out details. The comet nucleus is about 4 km across. Credits: ESA/Rosetta/NAVCAM/Ken Kremer/Marco Di Lorenzo
The comet nucleus is about 4 km (2.5 mi) across.
The team is in a race against time to select a suitable landing zone soon since the comet warms up and the surface becomes ever more active as it swings in closer to the sun and makes the landing ever more hazardous.
Stay tuned here for Ken’s continuing Rosetta, Earth and Planetary science and human spaceflight news.
Five candidate sites were identified on Comet 67P/Churyumov-Gerasimenko for Rosetta’s Philae lander. The approximate locations of the five regions are marked on these OSIRIS narrow-angle camera images taken on 16 August 2014 from a distance of about 100 km. Enlarged insets below highlight 5 landing zones. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Processing: Marco Di Lorenzo/Ken Kremer
Astronomy Cast’s 2014/15 season begins! With Rosetta’s arrival at Comet 67/P, we’re about to see a comet up close and personal. What will it take to explore, exploit and enjoy the asteroids and comets hurtling around our Solar System. And how does science fiction have it all wrong?? Continue reading “Astronomy Cast Ep. 351: Asteroid Adventures”
MAVEN is NASA’s next Mars Orbiter and will investigate how the planet lost most of its atmosphere and water over time. Credit: NASA
MAVEN to conduct up close observations of Comet Siding Spring during Oct. 2014 MAVEN is NASA’s next Mars Orbiter and will investigate how the planet lost most of its atmosphere and water over time. Credit: NASA
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NASA’s MAVEN Mars Orbiter is “ideally” instrumented to uniquely “map the composition of Comet Siding Spring” in great detail when it streaks past the Red Planet during an extremely close flyby on Oct. 19, 2014 – thereby providing a totally “unexpected science opportunity … and a before and after look at Mars atmosphere,” Prof. Bruce Jakosky, MAVEN’s Principal Investigator of CU-Boulder, CO, told Universe Today in an exclusive interview.
The probes state-of-the-art ultraviolet spectrograph will be the key instrument making the one-of-a-kind compositional observations of this Oort cloud comet making its first passage through the inner solar system on its millions year orbital journey.
“MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) is the ideal way to observe the comet coma and tail,” Jakosky explained.
“The IUVS can do spectroscopy that will allow derivation of compositional information.”
“It will do imaging of the entire coma and tail, allowing mapping of composition.”
Comet: Siding Spring The images above show — before and after filtering — comet C/2013 A1, also known as Siding Spring, as captured by Wide Field Camera 3 on NASA’s Hubble Space Telescope. Image Credit: NASA, ESA, and J.-Y. Li (Planetary Science Institute)
Moreover the UV spectrometer is the only one of its kind amongst NASA’s trio of Martian orbiters making its investigations completely unique.
“IUVS is the only ultraviolet spectrometer that will be observing the comet close up, and that gives the detailed compositional information,” Jakosky elaborated
And MAVEN, or the Mars Atmosphere and Volatile Evolution, is arriving just in the nick of time to fortuitously capture this fantastically rich data set of a pristine remnant from the solar system’s formation.
The spacecraft reaches Mars in less than 15 days. It will rendezvous with the Red Planet on Sept. 21 after a 10 month interplanetary journey from Earth.
Furthermore, since MAVEN’s purpose is the first ever detailed study of Mars upper atmosphere, it will get a before and after look at atmospheric changes.
“We’ll take advantage of this unexpected science opportunity to make observations both of the comet and of the Mars upper atmosphere before and after the comet passage – to look for any changes,” Jakosky stated.
How do MAVEN’s observations compare to NASA’s other orbiters Mars Odyssey (MO) and Mars Reconnaissance Orbiter (MRO), I asked?
“The data from the other orbiters will be complementary to the data from IUVS.”
“Visible light imaging from the other orbiters provides data on the structure of dust in the coma and tail. And infrared imaging provides information on the dust size distribution.”
IUVS is one of MAVENS’s nine science sensors in three instrument suites targeted to study why and exactly when did Mars undergo the radical climatic transformation.
How long will MAVEN make observations of Comet C/2013 A1 Siding Spring?
“We’ll be using IUVS to look at the comet itself, about 2 days before comet nucleus closest approach.”
“In addition, for about two days before and two days after nucleus closest approach, we’ll be using one of our “canned” sequences to observe the upper atmosphere and solar-wind interactions.”
“This will give us a detailed look at the upper atmosphere both before and after the comet, allowing us to look for differences.”
Describe the risk that Comet Siding Spring poses to MAVEN, and the timing?
“We have the encounter with Comet Siding Spring about 2/3 of the way through the commissioning phase we call transition.”
“We think that the risk to the spacecraft from comet dust is minimal, but we’ll be taking steps to reduce the risk even further so that we can move on toward our science mission.”
“Throughout this entire period, though, spacecraft and instrument health and safety come first.”
This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, 2014 the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers). Credit: NASA/JPL-Caltech
What’s your overall hope and expectation from the comet encounter?
“Together [with the other orbiters], I’m hoping it will all provide quite a data set!
“From Mars, the comet truly will fill the sky!” Jakosky gushed.
The comet’s nucleus will fly by Mars at a distance of only about 82,000 miles (132,000 kilometers) at 2:28 p.m. ET (18:28 GMT) on Oct. 19, 2014. That’s barely 1/3 the distance from the Earth to the Moon.
What’s the spacecraft status today?
“Everything is on track.”
Maven spacecraft trajectory to Mars on Sept. 4, 2014. Credit: NASA
The $671 Million MAVEN spacecraft’s goal is to study Mars upper atmosphere to explore how the Red Planet lost most of its atmosphere and water over billions of years and the transition from its ancient, water-covered past, to the cold, dry, dusty world that it has become today.
MAVEN soared to space over nine months ago on Nov. 18, 2013 following a flawless blastoff from Cape Canaveral Air Force Station’s Space Launch Complex 41 atop a powerful Atlas V rocket and thus began a 10 month interplanetary voyage from Earth to the Red Planet.
It is streaking to Mars along with ISRO’sMOM orbiter, which arrives a few days later on September 24, 2014.
So far it has traveled 95% of the distance to the Red Planet, amounting to over 678,070,879 km (421,332,902 mi).
As of Sept. 4, MAVEN was 205,304,736 km (127,570,449 miles) from Earth and 4,705,429 km (2,923,818 mi) from Mars. Its Earth-centered velocity is 27.95 km/s (17.37 mi/s or 62,532 mph) and Sun-centered velocity is 22.29 km/s (13.58 mi/s or 48,892 mph) as it moves on its heliocentric arc around the Sun.
One-way light time from MAVEN to Earth is 11 minutes and 24 seconds.
MAVEN is NASA’s next Mars orbiter and launched on Nov. 18, 2014 from Cape Canaveral, Florida. It will study the evolution of the Red Planet’s atmosphere and climate. Universe Today visited MAVEN inside the clean room at the Kennedy Space Center. With solar panels unfurled, this is exactly how MAVEN looks when flying through space and circling Mars and observing Comet Siding Spring. Credit: Ken Kremer/kenkremer.com
Stay tuned here for Ken’s continuing MAVEN, MOM, Rosetta, Opportunity, Curiosity, Mars rover and more Earth and planetary science and human spaceflight news.
NASA’s Mars bound MAVEN spacecraft launches atop Atlas V booster at 1:28 p.m. EST from Space Launch Complex 41 at Cape Canaveral Air Force Station on Nov. 18, 2013. Image taken from the roof of the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center. Credit: Ken Kremer/kenkremer.comNASA’s MAVEN Mars orbiter, chief scientist Prof. Bruce Jakosky of CU-Boulder and Ken Kremer of Universe Today inside the clean room at the Kennedy Space Center on Sept. 27, 2013. MAVEN launched to Mars on Nov. 18, 2013 from Florida. Credit: Ken Kremer/kenkremer.com
Illustration of Comet 67P/C-G brought down to Earth in the city of Los Angeles, Calif. Compare to the same image (below) as viewed in space. Credit: ESA and anosmicovni
All the pictures we’ve seen of Rosetta’s target comet 67P/C-G show it reflecting brightly against the background of outer space. And well they should. Space is black as night. But if we were to see the comet against a more familiar earthly backdrop, we’d be shocked by its appearance. Instead of icy white, Rosetta’s would appear the color of a fresh asphalt parking lot. Most comets, including Rosetta’s, are no brighter than the charcoal briquettes you use to grill hamburgers.
Astronomers rank an object’s reflectivity by its albedo (al-BEE-do). A body that reflects 100% of the light is said to have an albedo of 1.0. Venus’ albedo is .75 and reflects 75% of the light it receives from the sun, while the darker Earth’s average is 30%. Trees and the darker-toned continents reflect much less light compared to Venus’ pervasive cloud cover. In contrast, the coal-dark moon reflects only 12% of the sunlight falling on it and fresh asphalt just 4% – smack in the middle of the 2-6% rangeof most known comets.
Photo of Comet 67P/C-G taken by Rosetta on August 6, 2014. Against the blackness of space, it appears whitish-grey. Credit: ESA
The brightest object in the solar system is Saturn’s icy moon Enceladus with a reflectivity of 99%. So why are comets so dark? It’s funny because before we sent the Giotto spacecraft to snap close-up pictures of Halley’s Comet in 1986, astronomers thought comets, being made of reflective ice, were naturally white. Not Halley and not every comet seen up close since then.
Comets are as dark as charcoal but appear light only because the sun illuminates them against the blackness of outer space. I shone a flashlight on a charcoal briquette (left) to simulate comet lighting. The same charcoal, when viewed in normal light, appears black. Credit; Bob King
Astronomers hypothesize that a comet grows a dark ‘skin’ both from accumulated dust and irradiation of its pristine ices by cosmic rays. Cosmic rays loosen oxygen atoms from water ice, freeing them to combine with simple carbon molecules present on comets to form larger, more complex and darker compounds resembling tars and crude oil.
Comet colored parking lots have been the rage for years. Both comets and fresh asphalt reflect about the same amount of light. Credit: Bob King
Over time, the comet can become insulated by dust and complex organic materials. Combined with a loss of ice to vaporization at each repeated swing past the sun, they stop outgassing and become inert or defunct comets similar to asteroids. And that might not be the end of the story. Occasionally, a dead comet or an object originally discovered as an asteroid can unexpectedly fire back up after years of inactivity and become a comet again temporarily. Astronomers call these peculiar critters ‘damocloids’.
One wonders what you’d see if you could slice open a 67P/Churyumov-Gerasimenko. Would it resemble an Oreo cookie with a dark exterior and creamy white inside? One of NASA’s instruments aboard Rosetta named Alice began mapping the comet last month. In its first far ultraviolet spectra of the surface, we learned just this week that 67P is “darker than charcoal black”. Alice also detected hydrogen and oxygen in the comet’s coma, or atmosphere.
Oreo cookies – a model of a comet nucleus? Credit: Evan-Amos
Rosetta scientists also discovered the comet’s surface so far shows no large water-ice patches. The team expected to see ice patches on the comet’s surface because it’s too far away for the sun’s warmth to turn its water into vapor.
“We’re a bit surprised at just how unreflective the comet’s surface is and how little evidence of exposed water-ice it shows,” said Alan Stern, Alice principal investigator at the Southwest Research Institute in Boulder, Colorado.
Four-image photo mosaic comprising images taken by Rosetta's navigation camera on 31 August 2014 from a distance of 61 km from comet 67P/Churyumov-Gerasimenko. The mosaic has been contrast enhanced to bring out details. The comet nucleus is about 4 km across. Credits: ESA/Rosetta/NAVCAM/Ken Kremer/Marco Di Lorenzo
Four-image photo mosaic comprising images taken by Rosetta’s navigation camera on 31 August 2014 from a distance of 61 km from comet 67P/Churyumov-Gerasimenko. The mosaic has been contrast enhanced to bring out details. The comet nucleus is about 4 km across.
Credits: ESA/Rosetta/NAVCAM/Ken Kremer – kenkremer.com/Marco Di Lorenzo
See rotated version and 4 individual images below[/caption]
ESA’s Rosetta orbiter has now moved in so close to its comet quarry that the primordial body overwhelms the screen, and thus its snapping mapping mosaics to capture the complete scene of the bizarre world so it can find the most suitable spot for the momentous Philae landing – upcoming in mid-November.
In fact Rosetta has ‘drawn and quartered’ the comet to collect high resolution views of Comet 67P/Churyumov-Gerasimenko with the navcam camera on Sunday, August 31.
The navcam quartet has just been posted to the Rosetta portal today, Monday, September 1, 2014. ESA invited readers to create global photo mosaics.
See above our four frame photo mosaic of navcam images Rosetta took on Aug. 31.
The purpose of taking the images as well as spectra and physical measurements up close is to find a ‘technically feasible’ Philae touchdown site that is both safe and scientifically interesting.
Below is the Rosetta teams four image navcam montage, arranged individually in a 2 x 2 raster.
Four-image montage comprising images taken by Rosetta’s navigation camera on 31 August 2014 from a distance of 61 km from comet 67P/Churyumov-Gerasimenko. The comet nucleus is about 4 km across. Credits: ESA/Rosetta/NAVCAM
The navcam image raster sequence was taken from a distance of 61 km from comet 67P.
“Roughly one quarter of the comet is seen in the corner of each of the four images. The four images are taken over an approximately 20 minute period, meaning that there is some motion of the spacecraft and rotation of the comet between the images. As a result, making a clean mosaic out of the four images is not simple,” according to ESA’s Rosetta blog.
As I reported here last week, the ‘Top 5’ landing site candidates have been chosen for the Rosetta orbiters piggybacked Philae lander for humankind’s first attempt to land on a comet.
The potential touchdown sites were announced on Aug. 25, based on a thorough analysis of high resolution measurements collected by ESA’s Rosetta spacecraft over the prior weeks since it arrived at the pockmarked Comet 67P/Churyumov-Gerasimenko on Aug. 6, 2014.
See our montage of the ‘Top 5’ landing sites below.
Five candidate sites were identified on Comet 67P/Churyumov-Gerasimenko for Rosetta’s Philae lander. The approximate locations of the five regions are marked on these OSIRIS narrow-angle camera images taken on 16 August 2014 from a distance of about 100 km. Enlarged insets below highlight 5 landing zones. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Processing: Marco Di Lorenzo/Ken Kremer
Rosetta is a mission of many firsts, including history’s first ever attempt to orbit a comet for long term study.
Philae’s history making landing on comet 67P is currently scheduled for around Nov. 11, 2014, and will be entirely automatic. The 100 kg lander is equipped with 10 science instruments.
The new images released today are the best taken so far by the Navcam camera. The probes OSIRIS science camera are even more detailed, and will hopefully be released by ESA soon!
“This is the first time landing sites on a comet have been considered,” said Stephan Ulamec, Lander Manager at DLR (German Aerospace Center), in an ESA statement.
Since rendezvousing with the comet after a decade long chase of over 6.4 billion kilometers (4 Billion miles), a top priority task for the science and engineering team leading Rosetta has been “Finding a landing strip” for the Philae comet lander.
“The clock is ticking’ to select a suitable landing zone soon since the comet warms up and the surface becomes ever more active as it swings in closer to the sun and makes the landing ever more hazardous.
This image of comet 67P/Churyumov-Gerasimenko shows the diversity of surface structures on the comet’s nucleus. It was taken by the Rosetta spacecraft’s OSIRIS narrow-angle camera on August 7, 2014. At the time, the spacecraft was 65 miles (104 kilometers) away from the 2.5 mile (4 kilometer) wide nucleus. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA/Enhanced processing Marco Di Lorenzo/Ken Kremer
The three-legged lander will fire two harpoons and use ice screws to anchor itself to the 4 kilometer (2.5 mile) wide comet’s surface. Philae will collect stereo and panoramic images and also drill 23 centimeters into and sample its incredibly varied surface.
Stay tuned here for Ken’s continuing Rosetta, Earth and Planetary science and human spaceflight news.
Four-image photo mosaic comprising images taken by Rosetta’s navigation camera on 31 August 2014 from a distance of 61 km from comet 67P/Churyumov-Gerasimenko. The mosaic has been rotated and contrast enhanced to bring out details. The comet nucleus is about 4 km across. Credits: ESA/Rosetta/NAVCAM/Ken Kremer/Marco Di LorenzoESA’s Rosetta spacecraft on final approach to Comet 67P/Churyumov-Gerasimenko in early August 2014. This collage of navcam imagery from Rosetta was taken on Aug. 1, 2, 3 and 4 from distances of 1026 km, 500 km, 300 km and 234 km. Not to scale. Credit: ESA/Rosetta/NAVCAM – Collage/Processing: Marco Di Lorenzo/Ken Kremer- kenkremer.com
Five candidate sites were identified on Comet 67P/Churyumov-Gerasimenko for Rosetta’s Philae lander. The approximate locations of the five regions are marked on these OSIRIS narrow-angle camera images taken on 16 August 2014 from a distance of about 100 km. Enlarged insets below highlight 5 landing zones. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Processing: Marco Di Lorenzo/Ken Kremer
Five candidate sites were identified on Comet 67P/Churyumov-Gerasimenko for Rosetta’s Philae lander. The approximate locations of the five regions are marked on these OSIRIS narrow-angle camera images taken on 16 August 2014 from a distance of about 100 km. Enlarged insets below highlight 5 landing zones. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Processing: Marco Di Lorenzo/Ken Kremer
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The ‘Top 5’ landing site candidates have been chosen for the Rosetta orbiters piggybacked Philae lander for humankind’s first attempt to land on a comet. See graphics above and below.
The potential touchdown sites were announce today, Aug. 25, based on high resolution measurements collected by ESA’s Rosetta spacecraft over the past two weeks since arriving at the bizarre and pockmarked Comet 67P/Churyumov-Gerasimenko on Aug. 6, 2014.
Rosetta is a mission of many firsts, including history’s first ever attempt to orbit a comet for long term study.
Philae’s history making landing on comet 67P is currently scheduled for around Nov. 11, 2014, and will be entirely automatic. The 100 kg lander is equipped with 10 science instruments.
“This is the first time landing sites on a comet have been considered,” said Stephan Ulamec, Lander Manager at DLR (German Aerospace Center), in an ESA statement.
Artist impression of Philae on the surface of comet 67P/Churyumov-Gerasimenko. Credit: ESA/ATG medialab
Since rendezvousing with the comet after a decade long chase of over 6.4 billion kilometers (4 Billion miles), a top priority task for the science and engineering team leading Rosetta has been “Finding a landing strip” for the Philae comet lander.
“The challenge ahead is to map the surface and find a landing strip,” said Andrea Accomazzo, ESA Rosetta Spacecraft Operations Manager, at the Aug. 6 ESA arrival live webcast.
So ‘the clock is ticking’ to select a suitable landing zone soon as the comet warms up and the surface becomes ever more active as it swings in closer to the sun and makes the landing ever more hazardous.
This past weekend, the site selection team met at CNES, Toulouse, France, and intensively discussed and scrutinized a preliminary list of 10 potential sites, and whittled that down to the ‘Top 5.’
Their goal was to find a ‘technically feasible’ touchdown site that was both safe and scientifically interesting.
“The site must balance the technical needs of the orbiter and lander during all phases of the separation, descent, and landing, and during operations on the surface with the scientific requirements of the 10 instruments on board Philae,” said ESA.
They also had to be within an ellipse of at least 1 square kilometer (six-tenths of a square mile) in diameter due to uncertainties in navigation as well as many other factors.
“For each possible zone, important questions must be asked: Will the lander be able to maintain regular communications with Rosetta? How common are surface hazards such as large boulders, deep crevasses or steep slopes? Is there sufficient illumination for scientific operations and enough sunlight to recharge the lander’s batteries beyond its initial 64-hour lifetime, while not so much as to cause overheating?” according to ESA.
Stephan Ulamec, Philae Lander Manager at DLR (German Aerospace Center) discusses landing during ESA webcast of Rosetta’s arrival at comet Comet 67P/Churyumov-Gerasimenko. Credit: ESA
The Landing Site Selection Group (LSSG) team was comprised of engineers and scientists from Philae’s Science, Operations and Navigation Centre (SONC) at CNES, the Lander Control Centre (LCC) at DLR, scientists representing the Philae Lander instruments as well as the ESA Rosetta team, which includes representatives from science, operations and flight dynamics.
“Based on the particular shape and the global topography of Comet 67P/ Churyumov-Gerasimenko, it is probably no surprise that many locations had to be ruled out,” said Ulamec.
“The candidate sites that we want to follow up for further analysis are thought to be technically feasible on the basis of a preliminary analysis of flight dynamics and other key issues – for example they all provide at least six hours of daylight per comet rotation and offer some flat terrain. Of course, every site has the potential for unique scientific discoveries.”
When Rosetta arrived on Aug. 6, it was initially orbiting at a distance of about 100 km (62 miles) in front of the comet. Carefully timed thruster firings then brought it to within about 80 km distance. And it is moving far closer – to within 50 kilometers (31 miles) and even closer!
Upon arrival the comet was 522 million km from the Sun. As Rosetta escorts the comet looping around the sun, they move much closer. By landing time in mid-November they are only about 450 million km (280 million mi) from the sun.
At closest approach on 13 August 2015 the comet and Rosetta will be 185 million km from the Sun. That corresponds to an eightfold increase in the light received from the Sun.
Five candidate sites were identified on Comet 67P/Churyumov-Gerasimenko for Rosetta’s Philae lander. The approximate locations of the five regions are marked on these OSIRIS narrow-angle camera images taken on 16 August 2014 from a distance of about 100 km. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Therefore Rosetta and Philae will simultaneously study the warming effects of the sun as the comet outgases dust, water and much more.
The short period Comet 67P/Churyumov-Gerasimenko has an orbital period of 6.5 years.
“The comet is very different to anything we’ve seen before, and exhibits spectacular features still to be understood,” says Jean-Pierre Bibring, a lead lander scientist and principal investigator of the CIVA instrument.
“The five chosen sites offer us the best chance to land and study the composition, internal structure and activity of the comet with the ten lander experiments.”
A close-up view of Comet 67P/Churyumov–Gerasimenko taken by the Rosetta spacecraft on Aug. 7, 2014. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
The ‘Top 5’ zones will be ranked by 14 September. Three are on the ‘head’ and two are on the ‘body’ of the bizarre two lobed alien world.
And a backup landing site will also be chosen for planning purposes and to develop landing sequences.
The ultimate selection of the primary landing site is slated for 14 October after consultation between ESA and the lander team on a “Go/No Go” decision.
The three-legged lander will fire two harpoons and use ice screws to anchor itself to the 4 kilometer (2.5 mile) wide comet’s surface. Philae will collect stereo and panoramic images and also drill 23 centimeters into and sample its incredibly varied surface.
Why study comets?
Comets are leftover remnants from the formation of the solar system. Scientists believe they delivered a vast quantity of water to Earth. They may have also seeded Earth with organic molecules – the building blocks of life as we know it.
Any finding of organic molecules will be a major discovery for Rosetta and ESA and inform us about the origin of life on Earth.
Read an Italian language version of this story by my imaging partner Marco Di Lorenzo – here
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Holger Sierks, OSIRIS principal investigator, discusses spectacular hi res comet images returned so far by Rosetta during the Aug. 6 ESA webcast from mission control at ESOC, Darmstadt, Germany. Credit: Roland KellerESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This collage of imagery from Rosetta combines Navcam camera images at right taken nearing final approach from July 25 (3000 km distant) to July 31, 2014 (1327 km distant), with OSIRIS wide angle camera image at left of comet’s expanding coma cloud on July 25. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM/OSIRIS/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Collage/Processing: Marco Di Lorenzo/Ken Kremer
Holger Sierks, OSIRIS principal investigator, discusses spectacular hi res comet images returned so far by Rosetta during the Aug. 6 ESA webcast from mission control at ESOC, Darmstadt, Germany. Credit: Roland Keller
Animation Caption: Possible landing sites on Comet 67P/Churyumov-Gerasimenko. The model shows the illumination of the comets surface and regions under landing site consideration for the Philae lander on board ESA’s Rosetta spececraft . Credit: CNES
“The race is on” to find a safe and scientifically interesting landing site for the Philae lander piggybacked on ESA’s Rosetta spacecraft as it swoops in ever closer to the heavily cratered Comet 67P/Churyumov-Gerasimenko since arriving two weeks ago after a decade long chase of 6.4 billion kilometers (4 Billion miles).
Rosetta made history by becoming the first ever probe from Earth to orbit a comet upon arrival on Aug. 6, 2014.
The probe discovered an utterly alien and bizarre icy wanderer that science team member Mark McCaughrean, of ESA’s Science Directorate, delightedly calls a ‘Scientific Disneyland.’
“It’s just astonishing,” he said during a live ESA webcast of the Aug. 6 arrival event.
Now, another audacious and history making event is on tap – Landing on the comet!
To enable a safe landing, Rosetta is moving in closer to the comet to gather higher resolution imaging and spectroscopic data. When Rosetta arrived on Aug. 6, it was initially orbiting at a distance of about 100 km (62 miles). As of today, carefully timed thruster firings have brought it to within about 80 km distance. And it will get far closer.
Right now a top priority task for the science and engineering team leading Rosetta is “Finding a landing strip” for the Philae comet lander.
Philae’s landing on comet 67P is currently scheduled for Nov. 11, 2014. The 100 kg lander is equipped with 10 science instruments
“The challenge ahead is to map the surface and find a landing strip,” said Andrea Accomazzo, ESA Rosetta Spacecraft Operations Manager, at the Aug. 6 ESA webcast.
The team responsibility for choosing the candidate sites comprises “the Landing Site Selection Group (LSSG), which comprises engineers and scientists from Philae’s Science, Operations and Navigation Centre (SONC) at CNES, the Lander Control Centre (LCC) at DLR, scientists representing the Philae Lander instruments, and supported by the ESA Rosetta team, which includes representatives from science, operations and flight dynamics,” according to an ESA statement.
This week the team is intensively combing through a preliminary list of 10 potential landing sites.
Over the weekend they will whittle the list down to five candidate landing sites for continued detailed analysis.
ESA will announce the Top 5 landing site candidates on Monday, Aug. 25.
Where will Philae land?
This image of comet 67P/Churyumov-Gerasimenko shows the diversity of surface structures on the comet’s nucleus. It was taken by the Rosetta spacecraft’s OSIRIS narrow-angle camera on August 7, 2014. At the time, the spacecraft was 65 miles (104 kilometers) away from the 2.5 mile (4 kilometer) wide nucleus. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA/Enhanced processing Marco Di Lorenzo/Ken Kremer
The decision rests on the results of Rosetta’s ongoing global mapping campaign, including high resolution imaging from the OSIRIS and NAVCAM cameras and further observations from the other science instruments, especially MIRO, VIRTIS, ALICE, GIADA and ROSINA.
The surface criteria for a suitable landing site include day time landing illumination, a balance between day and night to allow the solar panels to recharge the batteries, avoiding steep slopes, large boulders and deep crevasses so it doesn’t topple over.
Of course the team also must consider the comet’s rotation period (12.4 hours) and axis of rotation (see animation at top). Sites near the equator offering roughly equal periods of day and night may be preferred.
The selection of the primary landing site is slated for mid-October after consultation between ESA and the lander team on a “Go/No Go” decision.
The three-legged lander will fire two harpoons and use ice screws to anchor itself to the 4 kilometer (2.5 mile) wide comet’s surface. Philae will collect stereo and panoramic images and also drill 23 centimeters into and sample its incredibly varied surface.
Artist impression of Philae on the surface of comet 67P/Churyumov-Gerasimenko. Credit: ESA/ATG medialab
Read an Italian language version of this story by my imaging partner Marco Di Lorenzo – here
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
A 3-D image from the Rosetta spacecraft showing Comet 67P/Churyumov-Gerasimenko and its boulder-strewn 'neck' region. Also visible is an exposed cliff face and numerous crater-like depressions. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
You always have a pair of those cardboard red-blue 3-D glasses by your desk, right? Well, grab them and take a look at this view of Comet 67P/Churyumov-Gerasimenko, just out from the Rosetta mission team. It almost feels like you’re right there with the spacecraft.
Notice the cliffs (see the exposed layers there?), boulders and depressions. The 3-D image was created using two images (you can see the two images here at the ESA blog) They were both taken on 7 August 2014, from a distance of 104 kilometres through the orange filter of the OSIRIS narrow-angle camera. ESA says the two images are separated by 17 minutes and the exposure time is 138 milliseconds.
