Hidden among the four new images of Comet 67P/Churyumov-Gerasimenko released by ESA this week are a pair of dusty jets shooting from the nucleus of Comet Churyumov-Gerasimenko. The photos were taken September 2, 2014 and posted as a mosaic of four separate images. I re-assembled the four, albeit imperfectly, and added some additional contrast to better show the dual geyser of ice crystals mixed with dust venting from the nucleus.
An earlier Rosetta photo taken of Comet 67P/ Churyumov-Gerasimenko from a great distance and deliberately overexposed showed jets of dust-laden vapor shooting from the comet, but this is the first image I’m aware of that shows both the comet’s surface and its much fainter exhalations.
Jets or sprays of vaporizing ice are what gives a comet its lively appearance. Dust released with water vapor is ultimately pushed back by the pressure of sunlight to grow 67P/C-G’s dust tail. Ultraviolet light from the sun causes volatiles within the vapor to fluoresce a pale blue, creating a second ion or gas tail. The coma or comet atmosphere is a mix of both.
We can expect the jets to grow stronger and hopefully more numerous as 67P/C-G approaches perihelion in August 2015. Because the spacecraft is maneuvering into orbit between the comet and sun, we don’t get the best view of jetting activity. The comet nucleus, illuminated by sunlight, drowns out the fainter jets. Rosetta will make an excursion to the nightside on September 24. Assuming the jets remain active, we might see them backlit by the sun as bright beams extending from the darkened nucleus into space.
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.
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.
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.
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.
An independent investigation committee is looking at why two European navigation satellites are in the wrong orbits following their launch from French Guiana last week.
While the first part of the launch went well, officials said telemetry from the satellites showed that the satellites were not where they were supposed to be. The probe is ongoing, but officials believe it is related to a stage of the Soyuz rocket that hefted the satellites into space.
“According to the initial analyses, an anomaly is thought to have occurred during the flight phase involving the Fregat upper stage, causing the satellites to be injected into a noncompliant orbit,” wrote launch provider Arianespace in an update on Saturday (Aug. 23).
The same day, the European Space Agency added that officials are looking into how the mission would be affected, if at all.
The Galileo satellites, the fifth and sixth of the constellation, are intended to serve as part of a cloud of navigation satellites that would be a European alternative to the United States GPS system. Officials are hoping to launch six to eight more satellites per year until 2017, when 24 satellites and six backups will be ready for full service.
The satellites were supposed to be in a circular orbit, inclined at 55 degrees to the Earth’s equator and have a maximum orbital radius (semi-major axis) of 29,900 km (18,579 miles). Telemetry now shows the satellites are in a non-circular orbit inclined at 49.8 degrees, with a semi-major axis of 26,200 km (16,280 miles).
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
Story updated[/caption]
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.
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.
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.
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.”
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.
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.
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.
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.
Did that impact 4.1 billion years ago ever leave a scar! Here, a Mars Express photo from late 2013 (and just highlighted now) shows off craters in Hellas Basin, which was formed when the planets in our young Solar System were under intense bombardment from leftover remnants.
But over time, wind and erosion on Mars have changed the nature of this basin, the German Space Agency explained.
“Over time, the interior of Hellas Planitia has been greatly altered by geological processes,” the German Space Agency stated.
“The wind has blown dust into the basin, glaciers and streams have transported and deposited sediment, and volcanoes have built up layers of low-viscosity lava on the floor of Hellas. Despite its exposure to erosion and coverage by deposits for a long period of time, it is the best-preserved large impact basin on Mars.”
What’s more, Hellas is so deep (four kilometers or 2.5 miles) that scientists suspect water could be stable near the bottom of the pit. That’s because the combination of pressure and temperature there could possibly support water for some time, which is different from much of the rest of Mars where the pressure is too thin for water to do much but evaporate.
The Cygnus commercial cargo ship ‘Janice Voss’ built by Orbital Sciences finished it’s month-long resupply mission and bid farewell to the International Space Station (ISS) this morning, Friday, Aug. 15, after station astronauts released the vessel from the snares of the Canadarm2 robotic arm at 6:40 a.m. EDT.
The on time release and departure took place as the massive orbiting lab complex was soaring 260 miles (400 km) above the west coast of Africa over the coastline of Namibia.
Expedition 40 Flight Engineer and ESA astronaut Alexander Gerst was in charge of commanding the vessels actual release from the snares on the end effector firmly grasping Cygnus at the terminus of the 58-foot (17-meter) long Canadian robotic arm.
Gerst was working at the robotics work station inside the seven windowed cupola, backed by fellow station crew member and NASA astronaut Reid Wiseman.
About two minutes later, Cygnus fired its thrusters to depart the million pound station and head toward a destructive fiery reentry into the Earth’s atmosphere over the Pacific Ocean on Sunday, Aug. 17.
Ground controllers at Mission Control, Houston had paved the way for Cygnus release earlier this morning when they unberthed the cargo ship from the Earth-facing port of the Harmony module at about 5:14 a.m. EDT.
This mission dubbed Orbital-2, or Orb-2, marks the second of at least eight operational cargo resupply missions to the ISS under Orbital’s Commercial Resupply Services (CRS) contract with NASA.
The Cygnus spacecraft was christened “SS Janice Voss” in honor of Janice Voss who flew five shuttle missions during her prolific astronaut carrier, worked for both NASA and Orbital Sciences and passed away in February 2012.
Cygnus roared to orbit during a spectacular blastoff on July 13 atop an Orbital Sciences Corp. Antares rocket on the Orb-2 mission at 12:52 p.m. (EDT) from the beachside Pad 0A at the Mid-Atlantic Regional Spaceport on NASA’s Wallops Flight Facility on the Eastern Shore of Virginia.
The US/Italian built pressurized Cygnus cargo freighter delivered 1,657 kg (3653 lbs) of cargo to the ISS Expedition 40 crew including over 700 pounds (300 kg) of science experiments and instruments, crew supplies, food, water, computer equipment, spacewalk tools and student research experiments.
The supplies are critical to keep the station flying and humming with research investigations.
The wide ranging science cargo and experiments includes a flock of 28 Earth imaging nanosatellites and deployers, student science experiments and small cubesat prototypes that may one day fly to Mars.
The “Dove” flock of nanosatellites will be deployed from the Kibo laboratory module’s airlock beginning next week. “They will collect continuous Earth imagery documenting natural and man-made conditions of the environment to improve disaster relief and increase agricultural yields” says NASA.
Cygnus arrived at the station after a three day chase. It was captured in open space on July 16, 2014 at 6:36 a.m. EDT by Commander Steve Swanson working at a robotics workstation in the cupola.
The by the book arrival coincided with the 45th anniversary of the launch of Apollo 11 on July 16, 1969 on America’s first manned moon landing mission by Neil Armstrong, Buzz Aldrin and Michael Collins.
Orbital Sciences was awarded a $1.9 Billion supply contract by NASA to deliver 20,000 kilograms (44,000 pounds) of research experiments, crew provisions, spare parts and hardware for 8 flights to the ISS through 2016 under the Commercial Resupply Services (CRS) initiative.
Stay tuned here for Ken’s continuing ISS, Rosetta, OCO-2, GPM, Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, MAVEN, MOM, Mars and more Earth & Planetary science and human spaceflight news.
Is this group of stars belonging to one generation, or more? That’s one of the things that was puzzling astronomers for decades, particularly when they were trying to pin down the age of IC 4499 — the globular cluster you see in this new picture from the Hubble Space Telescope.
“It has long been believed that all the stars within a globular cluster form at the about same time, a property which can be used to determine the cluster’s age,” stated information from the European Space Agency reposted on NASA’s website.
“For more massive globulars however, detailed observations have shown that this is not entirely true — there is evidence that they instead consist of multiple populations of stars born at different times.”
IC 4499 is somewhere in between these extremes, but only has a single generation of stars — its gravity wasn’t quite enough to pull in neighboring gas and dust to create more. Goes to show you how important it is to re-examine the results in science.
The central piece of the “pathfinder” backplane that will hold all the mirrors for NASA’s James Webb Space Telescope (JWST) has arrived at the agency’s Goddard Space Flight Center in Maryland for critical assembly testing on vital parts of the mammoth telescope.
The pathfinder backplane arrived at Goddard in July and has now been hoisted in place onto a huge assembly stand inside Goddard’s giant cleanroom where many key elements of JWST are being assembled and tested ahead of the launch scheduled for October 2018.
The absolutely essential task of JWST’s backplane is to hold the telescopes 18 segment, 21-foot-diameter primary mirror nearly motionless while floating in the utterly frigid space environment, thereby enabling the telescope to peer out into deep space for precise science gathering measurements never before possible.
Over the next several months, engineers will practice installing two spare primary mirror segments and one spare secondary mirror onto the center part of the backplane.
The purpose is to gain invaluable experience practicing the delicate procedures required to precisely install the hexagonal shaped mirrors onto the actual flight backplane unit after it arrives.
The telescopes primary and secondary flight mirrors have already arrived at Goddard.
The mirrors must remained precisely aligned in space in order for JWST to successfully carry out science investigations. While operating at extraordinarily cold temperatures between -406 and -343 degrees Fahrenheit the backplane must not move more than 38 nanometers, approximately 1/1,000 the diameter of a human hair.
The backplane and every other component must function and unfold perfectly and to precise tolerances in space because JWST has not been designed for servicing or repairs by astronaut crews voyaging beyond low-Earth orbit into deep space, William Ochs, Associate Director for JWST at NASA Goddard told me in an interview during a visit to JWST at Goddard.
Watch this video showing movement of the pathfinder backplane into the Goddard cleanroom.
Video Caption: This is a time-lapse video of the center section of the ‘pathfinder’ backplane for NASA’s James Webb Space Telescope being moved into the clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Credit: NASA/Chris Gunn
The actual flight backplane is comprised of three segments – the main central segment and a pair of outer wing-like parts which will be folded over into launch configuration inside the payload fairing of the Ariane V ECA booster rocket. The telescope will launch from the Guiana Space Center in Kourou, French Guiana in 2018.
Both the backplane flight unit and the pathfinder unit, which consists only of the center part, are being assembled and tested by prime contractor Northrop Grumman in Redondo Beach, California.
The test unit was then loaded into a C-5, flown to the U.S. Air Force’s Joint Base Andrews in Maryland and unloaded for transport by trailer truck to NASA Goddard in Greenbelt, Maryland.
JWST is the successor to the 24 year old Hubble Space Telescope and will become the most powerful telescope ever sent to space.
Webb is designed to look at the first light of the Universe and will be able to peer back in time to when the first stars and first galaxies were forming.
The Webb Telescope is a joint international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).
NASA has overall responsibility and Northrop Grumman is the prime contractor for JWST.
Read my story about the recent unfurling test of JWST’s sunshade – here.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Mark your calendars, astronomy geeks: exactly one year from today, the comet the Rosetta spacecraft is chasing will make its closest approach to the Sun. As Comet 67P/Churyumov–Gerasimenko draws closer to the star, the radiation pressure will cause gas, ice and dust to stream off the comet in ever greater quantities, scientists expect.
But that process is already starting. Preliminary measurements by a dust detector aboard the Rosetta spacecraft show that dust is at least as frequent — or perhaps even more abundant — than what models have predicted. Meanwhile, as reported on Universe Today earlier this week, Rosetta’s COSIMA instrument is also doing dust measurements.
Rosetta’s Grain Impact Analyser and Dust Accumulator (GIADA) has already detected four dust grains on its impact sensor. The detections took place between Aug. 1 and Aug. 5 at various distances as Rosetta approached the comet, starting from as far as 814 kilometers (506 miles) to as close as 179 kilometers (111 miles). Rosetta arrived at the comet on Aug. 6.
The first impact was just a tad higher than the detection limit for GIADA, scientists said. They also estimated how big the grains are based on how quickly they crash into the impact detector — anywhere from tens of microns (the width of a human hair) to a few hundreds of microns across.
While the results are scientifically interesting, the European Space Agency pointed out that they will also have practical use.
A lander called Philae is expected to touch down on the comet in November, so dust predictions will help planning for that. And for Rosetta itself, knowing the dust environment can help protect the spacecraft from strikes.
“GIADA will also provide inputs to other instruments on-board Rosetta, and will help improve coma dust models in support of the Philae landing operations,” ESA stated.
“Furthermore, GIADA will play an important role for the health and the safety of Rosetta and its instruments, providing information about the deposition rates of dust on optical components and critical parts of the spacecraft, such as the solar panels.”
ESA added that the grains themselves are likely a mixture of silicates, organics and some other stuff. Ice from the nucleus surrounds the grains, and the ice itself becomes a gas when the Sun warms the comet. Dust surrounds the comet in a coma and as it gets closer to the Sun, it streams out as a tail.