Comets Archives

August 11, 2014December 23, 2015 by Ken Kremer

Coma Dust Collection Science starts for Rosetta at Comet 67P/Churyumov-Gerasimenko

Rosetta NAVCAM image taken on 10 August 2014 from a distance of about 110 km from comet 67P/Churyumov-Gerasimenko. The comet nucleus is about 4 km across. Credit: ESA/Rosetta/NAVCAM

With the historic arrival of the European Space Agency’s (ESA) Rosetta spacecraft at destination Comet 67P/Churyumov-Gerasimenko flawlessly accomplished on August 6, 2014 after a decade long journey, ground breaking up close science at this bizarre world has begun while the team diligently and simultaneously searches for a landing site for the attached Philae comet lander.

Rosetta started collecting cometary dust from the coma encircling the comet’s nucleus with the onboard COSIMA instrument on Sunday, August 10, 2014 as the spacecraft orbits around and ahead of the icy wanderer from a distance of approximately 100 kilometers (62 miles). See coma image below.

Hopes are high that unprecedented science discoveries await at this alien world described as a “Scientific Disneyland,” by Mark McCaughrean, senior scientific adviser to ESA’s Science Directorate, during ESA’s live arrival day webcast. “It’s just astonishing.”

COSIMA stands for Cometary Secondary Ion Mass Analyser and is one of Rosetta’s suite of 11 state-of-the-art science instruments with a combined mass of 165 kg.

Its purpose is to conduct the first “in situ” analysis of the grains of dust particles emitted from the comets nucleus and determine their physical and chemical characteristics, including whether they are organic or inorganic – in essence what is cometary dust material made of and how it differs from the surface composition.

COSIMA will collect the coma dust using 24 specially designed ‘target holders’ – the first of which was opened to study the comets environment on Aug. 10. Since the comet is not especially active right now, the team plans to keep the target holder open for at least a month and check the progress of any particle collections on a weekly basis.

COSISCOPE image of the first target taken on 19 July 2014 (before the exposure, on 10 August, for cometary dust collection). The 1x1 cm target consists of a gold plate covered with a thin layer (30 µm) of gold nanoparticles (“gold black”). Illumination is by two LEDs, from the right side in this case. The bright dots on the vertical strip on the right side are used for target identification and for defining the coordinate system. Credits: ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S — COSISCOPE image of the first target taken on 19 July 2014 (before the exposure, on 10 August, for cometary dust collection). The 1×1 cm target consists of a gold plate covered with a thin layer (30 µm) of gold nanoparticles (“gold black”). Illumination is by two LEDs, from the right side in this case. The bright dots on the vertical strip on the right side are used for target identification and for defining the coordinate system. Credits: ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S

In fact the team says the coma environment “is still comparable to a high-quality cleanroom”at this time.

But everyone expects that to change radically as Rosetta continues escorting Comet 67P as it loops around the sun, getting closer and warming the surface every day and until reaching perihelion in August 2015.

COSIMA is managed by the Max Planck Institute for Solar System Research (Max-Planck-Institut für Sonnensystemforschung ) in Katlenburg-Lindau, Germany, with Principal Investigator Martin Hilchenbach.

There are also substantial contributions from the Institut d’Astrophysique Spatiale in France, Finnish Meteorological Institute, Osterreichisches Forschungszentrum Seibersdorf and more.

The target holders measure about one square centimeter and were developed by the Universität der Bundeswehr in Germany.

Each of these targets measures one square centimeter and is comprised of a gold plate covered with a thin 30 µm layer of gold nanoparticles (“gold black”) which the team says should “decelerate and capture cometary dust particles impacting with velocities of ~100 m/s.”

The target will be illuminated by a pair of LED’s to find the dust particles. The particles will be analyzed by COSIMA’s built in mass spectrometer after being located on the target holder by the French supplied COSISCOPE microscopic camera and ionized by a beam of indium ions.

Photo of the COSIMA (Cometary Secondary Ion Mass Analyser) instrument on Rosetta. Credit: Max Planck Institute for Solar System Research/ESA

The team expects any grains found on the first target to be analyzed by mid-September 2014.

“COSIMA uses the method of Secondary Ion Mass Spectrometry. They will be fired at with a beam of Indium ions. This will spark individual ions (we say secondary ions) from their surfaces, which will then be analysed with COSIMA’s mass spectrometer,” according to a description from the COSIMA team.

The mass spec has the capability to analyze the elemental composition in an atomic mass range of 1 to 4000 atomic mass units, determine isotopic abundances of some key elements, characterize organic components and functional groups, and conduct mineralic and petrographic characterization of the inorganic phases, all of which will inform as as never before about solar system chemistry.

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 and their identification by COSIMA will be a major discovery for Rosetta and ESA and inform us about the origin of life on Earth.

Data obtained so far from Rosetta’s VIRTIS instrument indicates the comets surface is too hot to be covered in ice and must instead have a dark, dusty crust.

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

Ken Kremer

…….

Read my Rosetta series here:

What’s Ahead for Rosetta – ‘Finding a Landing Strip’ on Bizarre Comet 67P/Churyumov-Gerasimenko

Rosetta Arrives at ‘Scientific Disneyland’ for Ambitious Study of Comet 67P/Churyumov-Gerasimenko after 10 Year Voyage

Rosetta on Final Approach to Historic Comet Rendezvous – Watch Live Here

Rosetta Probe Swoops Closer to Comet Destination than ISS is to Earth and Reveals Exquisite Views

Rosetta Orbiter less than 500 Kilometers from Comet 67P Following Penultimate Trajectory Burn

Rosetta Closing in on Comet 67P/Churyumov-Gerasimenko after Decade Long Chase

August 7, 2014December 23, 2015 by Ken Kremer

What’s Ahead for Rosetta – ‘Finding a Landing Strip’ on Bizarre Comet 67P/Churyumov-Gerasimenko

NAVCAM image taken by Rosetta on 5 August 2014 from a distance of about 145 km from comet 67P/Churyumov-Gerasimenko. Image has been rotated 180 degrees. Credit: ESA/Rosetta/NAVCAM

Where would you land here?
Newly released NAVCAM image taken by Rosetta on 5 August 2014 from a distance of about 145 km from comet 67P/Churyumov-Gerasimenko. Image has been rotated 180 degrees. Credit: ESA/Rosetta/NAVCAM[/caption]

Following the flawless and history making arrival of the European Space Agency’s (ESA) Rosetta spacecraft at its long sought destination of Comet 67P/Churyumov-Gerasimenko on Wednesday, Aug. 6, the goal of conducting ground breaking science at this utterly alien and bizarre icy wanderer that looks like a ‘Scientific Disneyland’ can actually begin.

Rosetta is the first spacecraft in history to rendezvous with a comet and enter orbit – after a more than 10 year chase of 6.4 billion kilometers (4 Billion miles) along a highly complex trajectory from Earth. The arrival event was broadcast live from mission control at ESA’s spacecraft operations centre (ESOC) in Darmstadt, Germany. Read my complete arrival story – here.

So what’s ahead for Rosetta? Another audacious and history making event – Landing on the comet!

A top priority task is also another highly complex task – ‘Finding a landing strip’ on the bizarre world of Comet 67P for the piggybacked Philae comet lander 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.

That will be no easy task based on the spectacular imagery captured by the OSIRIS high resolution science camera and the Navcam camera that has revealed an utterly wacky and incredibly differentiated world like none other we have ever visited or expected when the mission was conceived.

Magnificently detailed new navcam images were released by ESA today, Aug, 7, streaming back to Earth across some 405 million kilometers (250 million miles) of interplanetary space – see above and below.

The team will have its hand full trying to find a safe spot for touchdown.

“We now see lots of structure and details. Lots of topography is visible on the surface,” said Holger Sierks, principal investigator for Rosetta’s OSIRIS camera from the Max Planck Institute for Solar System Research in Gottingen, Germany, during the webcast.

“There is a big depression and 150 meter high cliffs, rubble piles, and also we see smooth areas and plains. It’s really fantastic”

“We see a village of house size boulders. Some about 10 meters in size and bigger and they vary in brightness. And some with sharp edges. We don’t know their composition yet,” explained Sierks.

Newly released NAVCAM image taken on 6 August 2014 from a distance of about 96 km from comet 67P/Churyumov-Gerasimenko. Credit: ESA/Rosetta/NAVCAM

The key to finding a safe landing site for Philae will be quickly conducting a global comet mapping campaign with OSIRIS, Navcam and the remaining suite of 11 science instruments to provide a detailed scientific study of the physical characteristics and chemical composition of the surface.

They also need to determine which areas are hard or soft.

Holger Sierks, OSIRIS principal investigator, discuss 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 — 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

“Our first clear views of the comet have given us plenty to think about,” says Matt Taylor, ESA’s Rosetta project scientist.

“Is this double-lobed structure built from two separate comets that came together in the Solar System’s history, or is it one comet that has eroded dramatically and asymmetrically over time? Rosetta, by design, is in the best place to study one of these unique objects.”

Yesterday’s (Aug. 6) critical final thruster firing placed the 1.3 Billion euro robotic emissary from Earth into a triangular shaped orbit about 100 kilometers (62 miles) above and in front of the comet’s incredibly varied surface.

Therefore the initial mapping will be conducted from the 100 km (62 mi.) standoff distance.

Since the landing is currently targeted for November 11, 2014, in barely three months time there is not a moment to waste.

“Over the next few months, in addition to characterizing the comet nucleus and setting the bar for the rest of the mission, we will begin final preparations for another space history first: landing on a comet,” says Taylor.

The team will identify up to five possible landing sites by late August and expect to choose the primary site by mid-September.

Then the team has to plan and build the programming and maneuvers for the final timeline to implement the sequence of events leading to the nailbiting landing.

With Rosetta now travelling in a series of 100 kilometer-long (62 mile-long) triangular arcs in front of the comet lasting about 3 days each, it will also be firing thrusters at each apex.

After catching up with the comet Rosetta will slightly overtake and enter orbit from the ‘front’ of the comet as both the spacecraft and 67P/CG move along their orbits around the Sun. Rosetta will carry out a complex series of manoeuvres to reduce the separation between the spacecraft and comet from around 100 km to 25-30 km. From this close orbit, detailed mapping will allow scientists to determine the landing site for the mission’s Philae lander. Immediately prior to the deployment of Philae in November, Rosetta will come to within just 2.5 km of the comet’s nucleus. This animation is not to scale; Rosetta’s solar arrays span 32 m, and the comet is approximately 4 km wide. Credit: ESA–C. Carreau

But it will also gradually edge closer over the next six weeks to about 50 km distance and then even closer to lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.

In November 2014, Rosetta will attempt another historic first when it deploys the Philae science lander from an altitude of just about 2.5 kilometers above the comet for the first ever attempt to land on a comet’s nucleus.

The three-legged lander will fire 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 into and sample its incredibly varied surface.

How will Philae land?

Stefan Ulamec, Philae Lander Manager from the German Aerospace Center (DLR) talked about the challenges of landing in a low gravity environment during the ESA webcast.

“The touchdown will be at a speed of just 1 m/s,” Ulamec explained. “This is like walking and bouncing against a wall.”

Details in an upcoming story!

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.

Stay tuned here for Ken’s continuing Rosetta, Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, commercial space, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.

Ken Kremer

…….

Read my Rosetta series here:

Rosetta Arrives at ‘Scientific Disneyland’ for Ambitious Study of Comet 67P/Churyumov-Gerasimenko after 10 Year Voyage

Rosetta on Final Approach to Historic Comet Rendezvous – Watch Live Here

Rosetta Probe Swoops Closer to Comet Destination than ISS is to Earth and Reveals Exquisite Views

Rosetta Orbiter less than 500 Kilometers from Comet 67P Following Penultimate Trajectory Burn

Rosetta Closing in on Comet 67P/Churyumov-Gerasimenko after Decade Long Chase

August 6, 2014December 23, 2015 by Ken Kremer

Rosetta Arrives at ‘Scientific Disneyland’ for Ambitious Study of Comet 67P/Churyumov-Gerasimenko after 10 Year Voyage

The image of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta’s OSIRIS narrow-angle camera on 3 August 2014 from a distance of 285 km. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Story updated[/caption]

“We’re at the comet! Yes,” exclaimed Rosetta Spacecraft Operations Manager Sylvain Lodiot, confirming the spacecraft’s historic arrival at Comet 67P/Churyumov-Gerasimenko during a live webcast this morning, Aug. 6, from mission control at ESA’s spacecraft operations centre (ESOC) in Darmstadt, Germany.

The European Space Agency’s (ESA) Rosetta comet hunter successfully reached its long sought destination after a flawless orbital thruster firing at 11 AM CEST to become the first spacecraft in history to rendezvous with a comet and enter orbit aimed at an ambitious long term quest to produce ground breaking science.

“Ten years we’ve been in the car waiting to get to scientific Disneyland and we haven’t even gotten out of the car yet and look at what’s outside the window,” Mark McCaughrean, senior scientific adviser to ESA’s Science Directorate, said during today’s webcast. “It’s just astonishing.”

“The really big question is where did we and the solar system we live in come from? How did water and the complex organic molecules that build up life get to this planet? Water and life. These are the questions that motivate everybody.”

“Rosetta is indeed the ‘rosetta stone’ that will unlock this treasure chest to all comets.”

Today’s rendezvous climaxed Rosetta’s decade long and 6.4 billion kilometers (4 Billion miles) hot pursuit through interplanetary space for a cosmic kiss with Comet 67P while speeding towards the inner Solar System at nearly 55,000 kilometers per hour.

The probe is sending back spectacular up close high resolution imagery of the mysterious binary, two lobed comet, merged at a bright band at the narrow neck of the celestial wanderer that looks like a ‘rubber ducky.’

“This is the best comet nucleus ever resolved in space with the sharpest ever views of the nucleus, with 5.5.meter pixel resolution,” said Holger Sierks, principal investigator for Rosetta’s OSIRIS camera from the Max Planck Institute for Solar System Research in Gottingen, Germany, during the webcast.

Back side view of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta’s OSIRIS narrow-angle camera on 3 August 2014 from a distance of 285 km. The image resolution is 5.3 metres/pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

“We now see lots of structure and details. Lots of topography is visible on the surface. We see the nucleus and outgassing activity. The outbursts are seen with overexposed images. It’s really fantastic”

“There is a big depression on the head and 150 meter high cliffs, rubble piles, and also we see smooth areas and plains. The neck is about 1000 meters deep and is a cool area. There is outgassing visible from the neck.”

“We see a village of house size boulders. Some about 10 meters in size and bigger they vary in brightness. And some with sharp edges. We don’t know their composition yet.”

“We don’t understand how its created yet. That’s what we’ll find out in coming months as we get closer.”

“Rosetta has arrived and will get even closer. We’ll get ten times the resolution compared to now.”

“The comet is a story about us. It will be the key in cometary science. Where did it form? What does it tell us about the water on Earth and the early solar system and where it come from?”

Following the blastoff on 2 March 2004 tucked inside the payload fairing of an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana, Rosetta traveled on a complex trajectory.

It conducted four gravity assist speed boosting slingshot maneuvers, three at Earth and one at Mars, to gain sufficient velocity to reach the comet, Lodiot explained.

The 1.3 Billion euro robotic emissary from Earth is now orbiting about 100 kilometers (62 miles) above the comet’s surface, some 405 million kilometers (250 million mi.) from Earth, about half way between the orbits of Jupiter and Mars.

The main event today, Aug. 6, was to complete an absolutely critical thruster firing which was the last of 10 orbit correction maneuvers (OCM’s). It started precisely on time at 11:00 AM CEST/09:00 GMT/5:00 AM EST, said Lodiot. The signal was one of the cleanest of the entire mission.

The orbital insertion engine firing dubbed the Close Approach Trajectory – Insertion (CATI) burn was scheduled to last about 6 minutes 26 seconds. Confirmation of a successful burn came some 28 minutes later.

“We’re at the comet! Yes,” Lodiot excitedly announced live whereupon the crowd of team members, dignitaries and journalists at ESOC erupted in cheers.

For the next 17 months, the probe will escort comet 67P as it loops around the Sun towards perihelion in August 2015 and then continue along on the outbound voyage towards Jupiter.

ESA’s incredibly bold mission will also deploy the three-legged piggybacked Philae lander to touch down and drill into and sample its incredibly varied surface a little over three months from now.

Together, Rosetta and Philae are equipped with a suite of 21 science instruments to conduct an unprecedented investigation to characterize the 4 km wide (2.5 mi.) comet and study how the pristine frozen body composed of ice and rock is transformed by the warmth of the Sun.

Comets are believed to have delivered a vast quantity of water to Earth. They may have also seeded Earth with organic molecules.

Close-up detail of comet 67P/Churyumov-Gerasimenko. The image was taken by Rosetta’s OSIRIS narrow-angle camera and downloaded today, 6 August. The image shows the comet’s ‘head’ at the left of the frame, which is casting shadow onto the ‘neck’ and ‘body’ to the right. The image was taken from a distance of 120 km and the image resolution is 2.2 metres per pixel. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA — Close-up detail of comet 67P/Churyumov-Gerasimenko. The image was taken by Rosetta’s OSIRIS narrow-angle camera and downloaded today, 6 August. The image shows the comet’s ‘head’ at the left of the frame, which is casting shadow onto the ‘neck’ and ‘body’ to the right.
The image was taken from a distance of 120 km and the image resolution is 2.2 metres per pixel. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta and Philae will also search for organic molecules, nucleic acids and amino acids, the building blocks for life as we know it by sampling and analyzing the comets nucleus and coma cloud of gas and dust.

“The first coma sampling could happen as early as next week,” said Matt Taylor, ESA’s Rosetta project scientist on the webcast.

After thoroughly mapping the comet, the team will command Rosetta to move even lower to 50 km altitude and then even lower to 30 km and less.

The scientists and engineers will search for up to five possible landing sites for Philae to prepare for the touchdown in mid-November 2014.

“We want to characterize the nucleus so we can land in November,” said Taylor. “We will have a ringside along with the comet as it moves inwards to the sun and then further out.”

Comet 67P/Churyumov-Gerasimenko activity on 2 August 2014. The IMAGE was taken by Rosetta’s OSIRIS wide-angle camera from a distance of 550 km. The exposure time of the image was 330 seconds and the comet nucleus is saturated to bring out the detail of the comet activity. Note there is a ghost image to the right. The image resolution is 55 metres per pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Studying comets will shed light on the history of water and life on Earth.

“We are going to places we have never been to before,” said Jean-Jacques Dordain, ESA’s Director General during the webcast.

“We want to get answers to questions to the origin to water and complex molecules on Earth. This opens up even more new questions than answers.”

Watch for updates.

Ken Kremer

……..

Read my Rosetta series here:

Rosetta on Final Approach to Historic Comet Rendezvous – Watch Live Here

Rosetta Probe Swoops Closer to Comet Destination than ISS is to Earth and Reveals Exquisite Views

Rosetta Orbiter less than 500 Kilometers from Comet 67P Following Penultimate Trajectory Burn

Rosetta Closing in on Comet 67P/Churyumov-Gerasimenko after Decade Long Chase

August 6, 2014December 23, 2015 by Nancy Atkinson

Stunning Images from Rosetta Show Closeup Views of Comet 67P/Churyumov-Gerasimenko

Close-up detail of comet 67P/Churyumov-Gerasimenko. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta has arrived! After traveling more than ten years, ESA’s Rosetta spacecraft reached comet 67P/Churyumov-Gerasimenko. These most recent images shared from the Rosetta team were obtained from a distance of 285 kilometers above 67P’s surface, and scientists say they surpass all pictures taken from earlier space missions of cometary surfaces. Visible are steep slopes and precipices, sharp-edged rock structure, prominent pits, and smooth, wide plains.

“It’s incredible how full of variation this surface is,” said Holger Sierks, the principal investigator of the OSIRIS imaging system on Rosetta. “We have never seen anything like this before in such great detail. “Today, we are opening a new chapter of the Rosetta mission. And already we know that it will revolutionize cometary science.”
Below, see more closeup images, including an animation from the navigation camera of Rosetta’s approach to the comet.

Read our full, detailed article about Rosetta’s arrival here.

Animation from the navigation camera of Rosetta’s view of Comet 67P/Churyumov-Gerasimenko as the spacecraft approached to enter orbit. Credit: ESA/Rosetta team.

Comet 67P/Churyumov-Gerasimenko by Rosetta’s OSIRIS narrow-angle camera on 3 August from a distance of 285 km. The image resolution is 5.3 metres/pixel. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

By planned overexposure of the nucleus of comet 67P/Churyumov-Gerasimenko structures in the coma become visible. This images was taken on August 2nd, 2014 from a distance of 550 kilometers. It was exposed for 5.5 minutes. ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

We’ll add more images as they become available, and this is just the beginning! In the next months, Rosetta will come closer than 10 kilometers to the comet’s surface, with one of the main goals to search for an appropriate landing site for the Philae lander. Philae is scheduled to touch down on the surface sometime this fall. Plus, Rosetta will stay close to the until the end of 2015. “We will have the unique opportunity to witness, how the comet’s activity forms and changes its surface”, said Sierks.

Here’s a video that shows more information of what Rosetta will be doing over the coming months:

Sources: ESA Flickr, Max Planck, ESA , ESA blog.

August 5, 2014December 23, 2015 by Ken Kremer

Rosetta on Final Approach to Historic Comet Rendezvous – Watch Live Here

ESA’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
Watch ESA’s Live Webcast here on Aug. 6 starting at 4 AM EDT/ 8 AM GMT[/caption]

After a decade long chase of 6.4 billion kilometers (4 Billion miles) through interplanetary space the European Space Agency’s (ESA) Rosetta spacecraft is now on final approach for its historic rendezvous with its target comet 67P scheduled for Wednesday morning, Aug. 6. some half a billion kilometers from the Sun. See online webcast below.

Rosetta arrives at Comet 67P/Churyumov-Gerasimenko in less than 12 hours and is currently less than 200 kilometers away.

You can watch a live streaming webcast of Rosetta’s Aug. 6 orbital arrival here, starting at 10:00 a.m. CEST/8 a.m. GMT/4 a.m. EDT/1 a.m. PDT via a transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.

Rosetta is the first mission in history to rendezvous with a comet and enter orbit around it. The probe will then escort comet 67P as it loops around the Sun, as well as deploy the piggybacked Philae lander to its uneven surface.

eurospaceagency on livestream.com. Broadcast Live Free

Orbit entry takes place after the probe initiates the last of 10 orbit correction maneuvers (OCM’s) on Aug. 6 starting at 11:00 CEST/09:00 GMT.

The thruster firing, dubbed the Close Approach Trajectory – Insertion (CATI) burn, is scheduled to last about 6 minutes 26 seconds. Engineers transmitted the commands last night, Aug. 4.

CATI will place the 1.3 Billion Euro Rosetta into an initial orbit at a distance of about 100 kilometers (62 miles).

Since the one way signal time is 22 min 29 sec, it will take that long before engineers can confirm the success of the CATI thruster firing.

As engineers at ESOC mission control carefully navigate Rosetta ever closer, the probe has been capturing spectacular imagery showing rocks, gravel and tiny crater like features on its craggily surface with alternating smooth and rough terrain and deposits of water ice.

See above and below our collages (created by Marco Di Lorenzo & Ken Kremer) of navcam camera approach images of the comet’s two lobed nucleus captured over the past week and a half. Another shows an OSIRIS camera image of the expanding coma cloud of water and dust.

The up close imagery revealed that the mysterious comet looks like a ‘rubber ducky’ and is comprised of two lobes merged at a bright band at the narrow neck in between.

Rosetta’s navcam camera has been commanded to capture daily images of the comet that rotates around once every 12.4 hours.

After orbital insertion on Aug. 6, Rosetta will initially be travelling in a series of 100 kilometer-long (62 mile-long) triangular arcs in front of the comet while firing thrusters at each apex. Further engine firings will gradually lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.

Rosetta will continue in orbit at comet 67P for a 17 month long study.

In November 2014, Rosetta will attempt another historic first when it deploys the piggybacked Philae science lander from an altitude of just about 2.5 kilometers above the comet for the first ever attempt to land on a comet’s nucleus. The lander will fire harpoons to anchor itself to the 4 kilometer (2.5 mile) wide comet’s surface.

Together, Rosetta and Philae will investigate how the pristine frozen comet composed of ice and rock is transformed by the warmth of the Sun. They will also search for organic molecules, nucleic acids and amino acids, the building blocks for life as we know it.

Rosetta was launched on 2 March 2004 on an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana.

Ken Kremer

August 4, 2014December 23, 2015 by Ken Kremer

Rosetta Probe Swoops Closer to Comet Destination than ISS is to Earth and Reveals Exquisite Views

NAVCAM image taken on 3 August 2014 from a distance of about 300 km from comet 67P/Churyumov-Gerasimenko. The Sun is towards the bottom of the image in this orientation. Credits: ESA/Rosetta/NAVCAM

Europe’s Rosetta comet hunter achieved another milestone today, Aug 4, swooping in closer to its long sought destination than the International Space Station (ISS) is to Earth – and its revealing the most exquisitely sharp and detailed view yet of the never before visited icy wanderer soaring half a billion kilometers from the Sun.

The absolutely delightful photo above is the latest navcam taken of Comet 67P/Churyumov-Gerasimenko by Rosetta’s navcam camera on Aug. 3 from a distance of 300 kilometers and shows rocks, gravel and tiny crater like features on its craggily surface of smooth and rough terrain with deposits of water ice.

Rosetta will make history as Earth’s first probe ever to rendezvous with and enter orbit around a comet.

Now barely a day away from rendezvous, the European Space Agency’s (ESA) robotic Rosetta spacecraft has closed to a distance of less than 300 kilometers away from Comet 67P and the crucial orbital insertion engine firing.

By comparison, the ISS and its six person crew orbits Earth at an altitude of some 400 kilometers (about 250 miles).

And its getter even closer! – Essentially to what we would call ‘the edge of space’ on Earth; 100 kilometers or 62 miles.

Having successfully completed the penultimate orbit correction maneuver on Aug. 3, the engineering team at mission control at the European Space Operations Centre (ESOC), in Darmstadt, Germany is making final preparations for the probes crucial last orbital insertion burn set for Wednesday, Aug. 6.

The Aug. 3 thruster firing known as the Close Approach Trajectory – pre-Insertion (CATP) burn lasted some 13 minutes and 12 seconds and reduced the spacecraft speed as planned by about 3.2 m/s.

“All looks good,” says Rosetta Spacecraft Operations Manager Sylvain Lodiot, according to an ESA operations tweet.

The final thruster firing upcoming soon on Aug. 6 is known as the Close Approach Trajectory – Insertion (CATI) burn.

The CATI orbit insertion firing will slow Rosetta to essentially the same speed as comet 67P and place it in an initial orbit at a distance of about 100 kilometers (62 miles).

The CATP and CATI trajectory firings have the combined effect of slowing Rosetta’s speed by some 3.5 m/s with respect to the comet which is traveling at 55,000 kilometers per hour (kph).

After a ten year chase of 6.4 billion kilometers (4 Billion miles) through interplanetary space and slingshots past Earth and Mars, the 1.3 Billion Euro spacecraft is at last ready to arrive at Comet 67P for a mission expected to last some 17 months.

The Navcam camera has been commanded to capture daily images of the comet that rotates around once every 12.4 hours.

See below our mosaic of navcam camera approach images of the nucleus captured of the mysterious two lobed comet, merged at a bright band in between as well as an OSIRIS camera image of the expanding coma cloud of water and dust..

After orbital inertion on Aug. 6, Rosetta will initially be travelling in a series of 100 kilometer-long triangular arcs while firings thrusters at each apex. Further engine firings will gradually lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.

Here is an ESA video showing Rosetta’s movements around the comet after arrival

Video caption: ESA’s Rosetta spacecraft will reach comet 67P/Churyumov-Gerasimenko in August 2014. After catching up with the comet Rosetta will slightly overtake and enter orbit from the ‘front’ of the comet as both the spacecraft and 67P/CG move along their orbits around the Sun. Rosetta will carry out a complex series of manoeuvres to reduce the separation between the spacecraft and comet from around 100 km to 25-30 km. Credit: ESA

Rosetta was launched on 2 March 2004 on an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana.

You can watch Rosetta’s Aug. 6 orbital arrival live from 10:45-11:45 CEST via a livestream transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.

Ken Kremer

August 3, 2014December 23, 2015 by Ken Kremer

Rosetta Orbiter less than 500 Kilometers from Comet 67P Following Penultimate Trajectory Burn

The Rosetta comet chaser is currently less than 500 kilometers (300 miles) from its target destination, Comet 67P/Churyumov-Gerasimenko following today’s (Aug. 3) successful completion of the spacecraft’s critically important penultimate trajectory burn, just three days before its history making arrival at the comet on Aug. 6.

The European Space Agency’s (ESA) 1.3 Billion euro Rosetta spacecraft is now under three days away from becoming Earth’s first probe ever to rendezvous with and enter orbit around a comet after a decade long hunt of 6.4 billion kilometers (4 Billion miles) through interplanetary space. The gap is narrowing with each passing second.

The last trajectory firing is set for Aug. 6. Altogether the final pair of trajectory burns will reduce the spacecrafts speed by some 3.5 meters per second (m/s) with respect to the comet which is traveling at 55,000 kilometers per hour (kph).

The probes latest Navcam camera image shot on Aug. 2, 2014 from a distance of about 500 kilometers from comet 67P/Churyumov-Gerasimenko shows exquisite detail of the rubber ducky shaped body tumbling end over end. See above.

See below our mosaic of navcam camera approach images of the nucleus captured over the past week and a half of the mysterious two lobed comet, merged at a bright band in between.

In November 2014, the Rosetta mothership will attempt another historic first when it deploys the Philae science lander from an altitude of just 1 or 2 kilometers for the first ever attempt to land on a comet’s nucleus. The lander will fire harpoons to anchor itself to the 4 kilometer wide (2.5 mile) comet’s surface.

Did life on Earth begin with the help of comet seeding? That’s a question the Rosetta science team seeks to help answer.

Today’s early morning thruster firing, officially known as the Close Approach Trajectory – pre-Insertion (CATP) burn, began as scheduled at 11:00 CEST (09:00 GMT) and was due to last for about 13 minutes and 12 seconds and bleed off some 3.2 m/s of spacecraft speed.

Although it ended a few seconds early, ESA reports that the CATP burn went well as engineers monitored the spacecraft communications at the European Space Operations Centre (ESOC), in Darmstadt, Germany via the agency’s 35 meter deep-space tracking station in New Norcia, Australia.

“All looks good,” says Rosetta Spacecraft Operations Manager Sylvain Lodiot, according to an ESA operations tweet.

CATP is part of the final series of ten orbit correction maneuvers (OCM’s) that culminates with the final thruster firing slated for Aug. 6 dubbed the Close Approach Trajectory – Insertion (CATI) burn.

“The CATI burn will reduce the relative velocity to about 1 m/s,” says Lodiot. That’s about equivalent to human walking speed.

The CATI orbit insertion firing will slow Rosetta to essentially the same speed as a comet and place it in orbit at an initial stand-off distance of about 100 kilometers (62 miles).

Rosetta will initially be travelling in a series of 100 kilometer-long triangular arcs while firings thrusters at each apex. Further engine firings will gradually lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.

“All systems on the spacecraft are performing well and the entire team is looking forward to a smooth arrival,” says Lodiot.

It will study and map the wanderer composed of primordial ice, rock, dust and more and search for a suitable landing site for Philae.

The one-way signal time from Earth to Rosetta and Comet 67P is currently 22 minutes and 27 seconds as both loop around the Sun at a distance of some 555 million kilometres away from the Sun at this time. The short period comet is located between the orbits of Jupiter and Mars.

Rosetta will escort Comet 67P as they journey together inwards around the sun and then travel back out towards Jupiter’s orbit and investigate the physical properties and chemical composition of the comets nucleus and coma of ice and dust for some 17 months.

Rosetta was launched on 2 March 2004 on an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana.

You can watch Rosetta’s Aug. 6 orbital arrival live from 10:45-11:45 CEST via a livestream transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.

Ken Kremer

August 1, 2014December 23, 2015 by Ken Kremer

Rosetta Closing in on Comet 67P/Churyumov-Gerasimenko after Decade Long Chase

ESA’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 to July 31, 2014, with OSIRIS wide angle camera image at left of comet’s coma on July 25 from a distance of around 3000 km. On July 31 Rosetta had approached to within 1327 km. 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 – kenkremer.com
Story updated[/caption]

The European Space Agency’s (ESA) Rosetta spacecraft is at last rapidly closing in on its target destination, Comet 67P/Churyumov-Gerasimenko, after a decade long chase of 6.4 billion kilometers through interplanetary space. See imagery above and below.

As of today, Friday, August 1, ESA reports that Rosetta has approached the ‘rubber ducky looking’ comet to within a distance of less than 1153 kilometers. That distance narrows with each passing moment as the speeding robotic probe moves closer and closer to the comet while looping around the sun at about 55,000 kilometers per hour (kph).

Rosetta is now just 5 days away from becoming Earth’s first probe ever to rendezvous and enter orbit around a comet.

See above our image collage of Rosetta nearing final approach with the spacecrafts most recent daily Navcam camera images, all taken within the past week starting on July 25 and including up to the most recently release image snapped on July 31. The navcam images are all to scale to give the sense of the spacecraft approaching the comet and revealing ever greater detail as it grows in apparent size in the cameras field of view. The navcam images were also taken at about the same time of day each day.

The highest resolution navcam image yet of the two lobed comet – merged at a bright band – was taken on July 31 from a distance of 1327 kilometers and published within the past few hours by ESA today, Aug 1. It shows the best view yet of the surface features of the mysterious bright necked wanderer composed of primordial ice, rock, dust and more.

The Navcam collage is combined with an OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) wide angle camera view of the comet and its asymmetric coma of ice and dust snapped on July 25 from a distance of around 3000 km, and with an exposure time of 300 seconds. The OSIRIS image covers an area of about 150 x 150 km (90 mi x 90 mi). The images have been contrast enhanced to bring out more detail.

Scientists speculate that the comets bright neck region could be caused by differences in material or grain size or topological effects.

Rosetta’s history making orbital feat is slated for Aug. 6 following the final short duration orbit insertion burns on Aug. 3 and Aug. 6 to place Rosetta into orbit at an altitude of about 100 kilometers (62 miles) where it will study and map the 4 kilometer wide comet for some 17 months.

The comet rotates around once every 12.4 hours.

Crop from the 31 July processed image of comet 67P/Churyumov-Gerasimenko, to focus on the comet nucleus. Credits: ESA/Rosetta/NAVCAM

“If any glitches in space or on ground had delayed the most recent burns, orbital mechanics dictate that we’d only have had a matter of a few days to fix the problem, re-plan the burn and carry it out, otherwise we run the risk of missing the comet,” says Trevor Morley, a flight dynamics specialist at ESOC.

In November 2014 the Rosetta mothership will deploy the Philae science lander for the first ever attempt to land on a comet’s nucleus using harpoons to anchor itself to the surface while the comet is rotating.

As Rosetta edges closer on its final lap, engineers at mission control at the European Space Operations Centre (ESOC), in Darmstadt, Germany have commanded the probes navigation camera (navcam) to capture daily images while the other science instruments also collect measurements analyzing the comets physical characteristics and chemical composition in detail.

ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This image collage from Rosetta combines Navcam camera images taken nearing final approach from July 25 (3000 km distant) to July 31, 2014 (1327 km distant). Top row shows images as seen by spacecraft. Bottom row shows images rotated to same orientation. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM. Collage/Processing: Marco Di Lorenzo/Ken Kremer

The probe has already discovered that the comet’s surface temperature is surprisingly warm at –70ºC, which is some 20–30ºC warmer than predicted. This indicates the surface is too hot to be covered in ice and must instead have a dark, dusty crust, says ESA.

Comet 67P/Churyumov-Gerasimenko is a short period comet some 555 million kilometres from the Sun at this time, about three times further away than Earth and located between the orbits of Jupiter and Mars.

You can watch the Aug. 6 orbital arrival live via a livestream transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.

While you were reading this the gap between the comet and Rosetta closed to less than 1000 kilometers!

The coma of Rosetta's target comet as seen with the OSIRIS wide-angle camera. The image spans 150 km and was taken on 25 July 2014 with an exposure time of 330 seconds. The greyscale relates to the particle density in the coma, with highest density close to the nucleus, becoming more diffuse further away. The hazy circular structure on the right is an artefact. The nucleus is also overexposured. The specks and the streaks in the background are attributed to background stars and cosmic rays. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA — The coma of Rosetta’s target comet as seen with the OSIRIS wide-angle camera. The image spans 150 km and was taken on 25 July 2014 with an exposure time of 330 seconds. The greyscale relates to the particle density in the coma, with highest density close to the nucleus, becoming more diffuse further away. The hazy circular structure on the right is an artefact. The nucleus is also overexposured. The specks and the streaks in the background are attributed to background stars and cosmic rays. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Stay tuned here for Ken’s continuing Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, commercial space, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.

Ken Kremer

Birthday cakes at @ESA_Rosetta Flight Dynamics are taking strange binary shapes these days... #ESOC. Credit: ESA — Birthday cakes at @ESA_Rosetta Flight Dynamics are taking strange binary shapes these days… #ESOC. Credit: ESA

July 31, 2014December 23, 2015 by Elizabeth Howell

This Model Of Earth’s Giant Impacts Makes Us Wonder How Life Arose

Artist's conception of early Earth after several large asteroid impacts, moving magma on to the surface. Credit: Simone Marchi/SwRI

In case you need a reminder that the solar system was a harsh place to grow up, the early Earth looks like it was in the middle of a shooting gallery in this model. The map that you see above shows a scenario for where researchers believe asteroids struck our planet about four billion to 4.5 billion years ago, which is very early in the Earth’s five-billion-year history.

The research reveals the surface of the Earth repeatedly being churned by these impacts as the young solar system came together, with small rocks gradually coalescing into planetesimals. Much of the leftover debris peppered the planets, including our own.

“Prior to approximately four billion years ago, no large region of Earth’s surface could have survived untouched by impacts and their effects,” stated Simone Marchi, who led the research and works at the Southwest Research Institute in Colorado.

“The new picture of the Hadean Earth emerging from this work has important implications for its habitability,” added Marchi, who is also senior researcher at NASA’s Solar System Exploration Research Virtual Institute.

In this dangerous early period, the researchers estimate the Earth was smacked by 1-4 asteroids or comets that were more than 600 miles (966 kilometers) wide — enough to wipe out life across the planet. They also believe that between 3-7 impactors were more than 300 miles (482 kilometers) wide, which would evaporate oceans across the world.

“During that time, the lag between major collisions was long enough to allow intervals of more clement conditions, at least on a local scale,” added Marchi. “Any life emerging during the Hadean eon likely needed to be resistant to high temperatures, and could have survived such a violent period in Earth’s history by thriving in niches deep underground or in the ocean’s crust.”

To produce the model, the researchers took a recent model of lunar impacts and applied it to Earth. The moon’s scarred surface helps them estimate what happened on our own planet, they said, because the craters provide an “absolute impactor flux” separate from any models that talk about how the Earth came together. Recall that erosion on the moon is very slow, providing accessible records of things that happened millions or billions of years ago.

The research was published in the journal Nature.

Source: NASA

July 31, 2014December 23, 2015 by Brian Koberlein

What Are Comet Tails?

The view of Comet PANSTARRS L4 on 03-22-2013 over Warrenton, Virginia. Modified Canon Rebel Xsi DSLR 30 second exposure, ISO 1600, University Optics 80mm F6 Refractor (600mm). Credit and copyright: John Chumack.

Comets are renowned for their big beautiful tails that stretch across the sky. But what’s in those things, anyway? And how can comets get multiple tails?

In the past, humans generally used one of two greetings for comets:
1. Dear God, what is that thing? Terrible omens! Surely we will all die in fire.
2. Dear God, what is that thing? Great omens! Surely we will all have a big party… where we all die in fire?

For example, the appearance of what came to be known as Halley’s comet in 1066 was seen as a bad omen for King Harold II. Conversely, it was a good omen for William the Conqueror.

Because of their tails and transitory nature, comets were long thought to be products of the Earth’s atmosphere. It wasn’t until the 1500s, when Tycho Brahe used parallax to determine a comet’s distance. He realized that they were Solar System objects, like planets.

So, good news, we no longer regard them as omens and everyone stopped panicking. Right? Wrong. When Comet Halley approached Earth in 1910, astronomers detected cyanide gas in its tail. French astronomer Camille Flammarion was quoted as saying the gas could “impregnate the atmosphere and possibly snuff out all life on the planet.” This caused a great deal of hysteria. Many bought gas masks and “comet pills” to protect themselves.

With the rise of photographic astronomy, it was found that comets often have two types of tails. A bright tail composed of ionized gas, and a dimmer one composed of dust particles. The ion tail always points away from the Sun. It’s actually being pushed away from the comet by the solar wind.

Comets often develop two tails as they near the sun - a curved dust tail and straight, ion tail. Credit: NASA — Comets often develop two tails as they near the sun – a curved dust tail and straight, ion tail. Credit: NASA

We now know that a comet’s ion tail contains “volatiles” such as water, methane, ammonia and carbon dioxide. These volatiles are frozen near the comet’s surface, and as they approach the Sun, they warm and become gaseous. This also causes dust on the comet’s surface to stream away. The heating of a comet by the Sun is not uniform.

Because of a comet’s irregular shape and rotation, some parts of the surface can be heated by sunlight, while other parts remain cold. In some cases this can mean that comets can have multiple tails, which creates amazing effects where different regions of a comet stream off volatiles.

Comet Lovejoy passing behind green oxygen and sodium airglow layers on December 22, 2011 seen from the space station. Credit: NASA/Dan Burbank

These ion tails can be quite large, and some have been observed to be nearly 4 times the distance of the Earth from the Sun. And even though they fill a great volume, they are also pretty diffuse. If you condensed a comet’s tail down to the density of water, it wouldn’t even fill a swimming pool.

We also now know that there isn’t a clear dividing line between comets and asteroids. It’s not the case the comets are dirty snowballs and asteroids are dry rocks. There is a range of variation, and asteroids can gain dusty or gaseous tails and take on a comet-like appearance. In addition, we’ve also found comets orbiting other stars, known as exocomets.

And finally one last fact, the term comet comes from the Latin cometa, which indicated a hairy star.

So, what’s your favorite comet? Tell us in the comets below. And if you like what you see, come check out our Patreon page and find out how you can get these videos early while helping us bring you more great content!