Rise And Shine! Rosetta’s Comet Emerges From Behind Sun, Much Brighter Than Before

Artist's impression (not to scale) of the Rosetta orbiter deploying the Philae lander to comet 67P/Churyumov–Gerasimenko. Credit: ESA–C. Carreau/ATG medialab.

After four months behind the sun from Earth’s perspective, comet 67P/Churyumov-Gerasimenko is back in view — and brighter than ever! New pictures of the comet reveal it is 50 percent brighter than the last images available from October 2013. You can see the result below the jump.

“The new image suggests that 67P is beginning to emit gas and dust at a relatively large distance from the Sun,” stated Colin Snodgrass, a post-doctoral researcher at the Max Planck Institute for Solar System Research in Germany. Snodgrass added that this confirms previous work he and his colleagues did showing that in March 2014, the comet’s activity could be seen from Earth.

Pictures were taken with the European Southern Observatory’s Very Large Telescope from 740 million kilometers (460 million miles) away. As you can see in the image below, several exposures were taken to obtain the fainter comet. And we know that scientists are eager to take a closer look with Rosetta.

Comet 67P/Churyumov-Gerasimenko on images obtained Feb. 28th, 2014 with the Very Large Telescope. Left: Several exposures were obtained of the faint comet, and superimposed upon each other, making stars appear as streaks. Right: The comet in an image processed to remove the stars. Credit: MPS/ESO
Comet 67P/Churyumov-Gerasimenko on images obtained Feb. 28th, 2014 with the Very Large Telescope. Left: Several exposures were obtained of the faint comet, and superimposed upon each other, making stars appear as streaks. Right: The comet in an image processed to remove the stars. Credit: MPS/ESO

In January, the Rosetta spacecraft woke up after 31 months of hibernation (a little later than expected, but still healthy as ever.) It’s en route to meet up with the comet in August and will stay alongside it at least until 2015’s end. The next major step is to wake up its lander, Philae, which will happen later this month.

Should all go to plan, Philae will make a daring landing on the comet in November to get an up-close view of the activity as the comet flies close to the sun. You can read more details in this past Universe Today story.

Source: Max Planck Institute for Solar System Research

Giant Planet May Be Lurking In ‘Poisonous’ Gas Around Beta Pictoris

Artist's conception of a hypothetical giant planet (left) in Beta Pictoris. The gas giant would sweep up comets into a swarm, causing frequent collisions. Astronomers using the Atacama Large Millimeter Array (ALMA) are calling this the "preferred model" for observations they made. Credit: Goddard Space Flight Center/F. Reddy

A Saturn-mass planet might be lurking in the debris surrounding Beta Pictoris, new measurements of a debris field around the star shown. If this could be proven, this would be the second planet found around that star.

The planet would be sheparding a giant swarm of comets (some in front and some trailing behind the planet) that are smacking into each other as often as every five minutes, new observations with the Atacama Large Millimeter/submillimeter Array (ALMA) show. This is the leading explanation for a cloud of carbon monoxide gas visible in the array.

“Although toxic to us, carbon monoxide is one of many gases found in comets and other icy bodies,” stated Aki Roberge, an astrophysicist at NASA’s Goddard Space Flight Center in Maryland who participated in the research. “In the rough-and-tumble environment around a young star, these objects frequently collide and generate fragments that release dust, icy grains and stored gases.”

ALMA captured millimeter-sized light from carbon monoxide and dust around Beta Pictoris, which is about 63 light-years from Earth (relatively close to our planet). The gas seems to be most prevalent in an area about 8 billion miles (13 kilometers) from the star — the equivalent distance of three times the length of Neptune’s location from the sun. The carbon monoxide cloud itself makes up about one-sixth the mass of Earth’s oceans.

Ultraviolet light from the star should be breaking up the carbon monoxide molecules within 100 years, so the fact there is so much gas indicates something must be replenishing it, the researchers noted. Their models showed that the comets would need to be destroyed every five minutes for this to happen (unless we are looking at the star at an unusual time).

While the researchers say they need more study to see how the gas is concentrated, their hypothesis is there is two clumps of gas and it is due to a big planet behaving similarly to what Jupiter does in our solar system. Thousands of asteroids follow behind and fly in front of Jupiter due to the planet’s massive gravity. In this more distant system, it’s possible that a gas giant planet would be doing the same thing with comets.

If the gas turns out to be in just one clump, however, another scenario would suggest two Mars-sized planets (icy ones) smashing into each other about half a million years ago. This “would account for the comet swarm, with frequent ongoing collisions among the fragments gradually releasing carbon monoxide gas,” NASA stated.

The research was published yesterday (March 6) in the journal Science and is led by Bill Dent, a researcher at the Joint ALMA Office in  Chile. You can read more information in press releases from NASA, the National Radio Astronomy Observatory and European Southern Observatory.

NEOWISE Spots a “Weirdo” Comet

Infrared image of comet NEOWISE (C/2014 C3). Credit: NASA/JPL-Caltech

NASA’s NEOWISE mission — formerly known as just WISE — has identified the first comet of its new near-Earth object hunting career… and, according to mission scientists, it’s a “weirdo.”

In its former life NASA’s WISE (Wide-field Infrared Survey Explorer) spacecraft scanned the entire sky in infrared wavelengths. It helped discover the galaxy’s coldest stars, the Universe’s brightest galaxies, and some of the darkest asteroids lurking in the main asteroid belt between Mars and Jupiter… as well as closer in to Earth’s neck of the woods.

After exhausting its supply of liquid coolant needed to shield itself from its own radiating heat, in 2011 WISE was put into a state of hibernation. It was awoken last year and rebranded NEOWISE, and set upon the task of locating unknown objects with orbits in the proximity of Earth’s.

Kevin Luhman discovered the brown dwarf pair in data from NASA's Wide-field Infrared Survey Explorer (WISE; artist's impression). Image: NASA/JPL-Caltech
Artist’s impression of the WISE satellite

To date several new asteroids have already been found by NEOWISE, and on February 14, 2014, it spotted its first comet.

“We are so pleased to have discovered this frozen visitor from the outermost reaches of our solar system,” said Amy Mainzer, NEOWISE principal investigator at JPL. “This comet is a weirdo — it is in a retrograde orbit, meaning that it orbits the sun in the opposite sense from Earth and the other planets.”

Designated “C/2014 C3 (NEOWISE),” the comet was 143 million miles (230 million km) away in the image above — a composite made from six infrared exposures. That’s 585 times the distance to the Moon, or about the average distance between the Earth and Mars.

The tail of the comet NEOWISE extends about 25,000 miles (40,000 km) to the right in the image.

Overall, C/2014 C3 (NEOWISE) was spotted six times before it moved out of range of the spacecraft’s view. The comet has a highly-eccentric 20-year orbit that takes it high above the plane of the Solar System and out past the orbit of Jupiter. Technically, with a perihelion distance greater than 1.3 AU, comet C/2014 C3 does not classify as a near-Earth object (and its orbit does not intersect Earth’s.) But it’s still good to know that NEOWISE is looking out for us.

Read more on JPL’s NEOWISE site here, and see details on the comet’s orbit on the Minor Planet Center’s website here and from JPL’s Small-Body Database here.

Source: NASA/JPL

Comet ISON Hosted A Rare Kind Of Nitrogen, Hinting At Reservoirs In Young Solar System

Spectacular photo of Comet ISON taken Nov. 15 from Charleston, Rhode Island, USA showing the recent outburst. Click to enlarge. Credit: Scott MacNeill

Comet ISON — that bright comet last year that broke up around Thanksgiving weekend — included two forms of nitrogen in its icy body, according to newly released observations from the Subaru Telescope.

Of the two types found, the discovery of isotope 15NH2 was the first time it’s ever been seen in a comet. Further, the observations from the Japanese team of astronomers show “there were two distinct reservoirs of nitrogen [in] the massive, dense cloud … from which our Solar System may have formed and evolved,” stated the National Astronomical Observatory of Japan.

Besides being pretty objects to look at, comets are considered valuable astronomical objects because they’re a sort of time capsule of conditions early in the universe. The “fresh” comets are believed to come from a vast area of icy bodies called the Oort Cloud, a spot that has been relatively untouched since the solar system formed about 4.6 billion years ago. Spying elements inside of comets can give clues as to what was present in our neighborhood when the sun and planets were just coming to be.

“Ammonia (NH3) is a particularly important molecule, because it is the most abundant nitrogen-bearing volatile (a substance that vaporizes) in cometary ice and one of the simplest molecules in an amino group (–NH2) closely related to life. This means that these different forms of nitrogen could link the components of interstellar space to life on Earth as we know it,” NAOJ stated.

You can read more details about the finding at the NAOJ website, or in Astrophysical Journal Letters.

Two Comets Pass in the Night Bound for Your Telescope

Spectacular photo of Comets C/2012 X1 LINEAR (top) and C/2013 R1 Lovejoy taken with a wide field 4-inch telescope before dawn Feb. 9, 2014. Credit: Damian Peach

Remember comets Lovejoy and C/2012 X1 LINEAR? We dropped in on them in late January. On Feb. 6 the two cruised within  2 degrees of each other as they tracked through Ophiuchus before dawn.  Were it not for bad weather, astrophotographer Damian Peach would have been out to record the cometary conjunction, but this unique photo, taken two mornings later, shows the two comets chasing each other across the sky. Of course they’re not really following one another, nor are they related,  but the illusion is wonderful.

Comets Lovejoy and X1 LINEAR are neighbors in northern Ophiuchus this month and next. This map shows the sky facing east about 1 hour 45 minutes before sunrise shortly before the start of morning twilight. Tick marks show the comets’ position every 5 days. Click to enlarge. Detailed map below. Created with Chris Marriott’s SkyMap software. Read more: http://www.universetoday.com/108569/lovejoy-and-x1-linear-comets-to-warm-up-your-mid-winter-mornings/#ixzz2slrnLMIx
Comets Lovejoy and X1 LINEAR are neighbors in northern Ophiuchus through Feb. 25. This map shows the sky facing east about 1 hour 45 minutes before sunrise shortly before the start of morning twilight. Tick marks show the comets’ position every 5 days. Detailed map below. Created with Chris Marriott’s SkyMap software.

Rarely do two relatively bright comets align so closely. Even more amazing was how much they looked alike. By good fortune I was able to see them both  through a 15-inch (37-cm) under a very dark sky this morning. Although Lovejoy’s faint, approximately 20′ long tail was fanned out more than X1’s, both tails were faint, short and pointed to the west-northwest. Lovejoy’s coma was slightly larger and brighter, but both comets’ comas diplayed similarly compact, bright centers.

This deeper map shows stars to about magnitude 8. Although both comets appear to be getting lower every morning, the westward seasonal drift of the stars will keep them in good view for the next few months. Click to enlarge. Created with Chris Marriott’s SkyMap software
This deeper map shows stars to about magnitude 8. Although both comets appear to be getting lower every morning, the westward seasonal drift of the stars will keep them in good view for the next few months. Click to enlarge. Created with Chris Marriott’s SkyMap software

Lovejoy currently hovers around magnitude 8.1, X1 LINEAR at 8.8 – less than a magnitude apart.  If you haven’t seen them yet, they’re still the brightest comets we’ll have around for another few months unless an unexpected visitor enters the scene.

After converging for weeks, the comets’ paths are now slowly diverging and separating. Look while you can; the waxing moon will soon rob these fuzzies of their fading glory when it enters the morning sky this coming Tuesday or Wednesday.

See this earlier article for more information on both comets.

NEOWISE Spots Mars-Crossing Comet

NASA's NEOWISE Mission takes aim at Comet A1 Siding Spring on January 16th, 2014 when the comet was 571 million kilometres distant. Credit: NASA/JPL-Caltech

One of the big ticket astronomical events of 2014 will be the close passage of Comet C/2013 A1 Siding Spring past the planet Mars in October 2014. Discovered just over a year ago from the Australian-based Siding Spring Observatory, this comet generated a surge of excitement in the astronomical community when it was discovered that it was going to pass very close to the planet Mars in late 2014.

Now, a fleet of spacecraft are poised to study the comet in unprecedented detail. Some of the first space-based observations of the comet have been conducted by NASA’s Hubble Space Telescope and the recently reactivated NEOWISE mission. And although the comet may not look like much yet in the infrared eyes of NEOWISE, its estimated 4 kilometre in diameter nucleus is already active and shedding about 100 kilograms of dust per second.

And although an impact has been since ruled out, it’s that dust that may present a hazard for Mars orbiting spacecraft, as well as a unique scientific observing opportunity.

“Our plans for using spacecraft at Mars to observe Comet A1 Siding Spring will be coordinated with plans for how the orbiters will duck and cover, if we need to do so that,” said NASA/JPL Mars Exploration Program chief scientist Rich Zurek.

The 2014 passage of Comet A1 Siding Spring through the inner solar system. Credit: NASA/JPL-Caltech
The 2014 passage of Comet A1 Siding Spring through the inner solar system. Credit: NASA/JPL-Caltech

Comet A1 Siding Spring is projected to pass within just 138,000 kilometres of Mars on October 19th, 2014. This is one-third the Earth-Moon distance, and 10 times closer than the closest recorded passage of a comet by the Earth, which was Comet D/1770 Lexell in the late 18th century. The comet will also miss the Martian moons of Phobos and Deimos, which have the closest orbits of any moons in the solar system at just 5,989 and 20,063 kilometres above the surface of Mars, respectively.

Assets in orbit around the Red Planet are also slated to observe the close approach and passage of Comet A1 Siding Spring, as well as any extraterrestrial meteor shower that its dust may generate.

“We could learn about the nucleus – its shape, its rotation, whether some areas on its surface are darker than others,” Zurek said in a recent NASA/JPL press release.

The rovers Curiosity and Opportunity are currently active on the surface of Mars. Above in orbit, we’ve got the European Space Agency’s Mars Express, and NASA’s Mars Odyssey and the Mars Reconnaissance Orbiter (MRO).  These will be joined by India’s Mars Orbiter Mission and NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft just weeks prior to the comet’s passage.

“A third aspect for investigation could be what effect the infalling particles have on the upper atmosphere of Mars,” Zurek said. “They might heat it and expand it, not unlike the effect of a global dust storm.”

Just last year, Mars based spacecraft caught sight of the ill-fated sungrazer Comet C/2012 S1 ISON as it passed Mars. But that dim passage yielded a scant pixel-sized view in the eyes of MRO’s HiRISE camera; Comet A1 Siding Spring will pass 80 times closer than Comet ISON and could yield a view of its nucleus dozens of pixels across.

Though the tenuous Martian atmosphere will shield to surface rovers from any micro-meteoroid impacts, they may also be witness to a surreptitious meteor shower from the debris shed by the comet, a first seen from the surface of another world.

But engineers will also be assessing the potential hazards that said particles may posed to spacecraft orbiting Mars as well.

“It’s way too early for us to know how much of a threat Siding Spring will be to our orbiters,” said JPL’s Mars Exploration Program chief engineer Soren Madsen recently. “It could go either way. It could be a huge deal or it could be nothing – or anything in between.”

In a worst case scenario, Mars orbiting spacecraft would be shuttered and oriented to “shelter in place” as the dust from the comet passes. There’s precedent for this in Earth orbit, as precious assets such as the Hubble Space Telescope were closed for business during the Leonid meteor storm of 1998.

“How active will Siding Spring be in April and May? We’ll be watching that,” Madsen continued. “But if the red alarm starts sounding in May, it would be too late to start planning how to respond. That’s why we’re doing what we’re doing right now.”

Comet A1 Siding Spring was the first comet discovered in 2013 at 7.2 Astronomical Units (AUs) distant. From our Earth based perspective, the comet will reach opposition on August 25th at 0.96 AU from the Earth, and approach 7’ from Mars on October 19th in the constellation Ophiuchus in evening skies. The comet reaches perihelion just 4 days later, and is slated to be a binocular comet around that time shining at magnitude +8.

The comet nucleus itself is moving in a retrograde orbit relative to Mars. Particles from A1 Siding Spring will slam into the atmosphere of Mars — and any spacecraft that happens to be in their way — at a velocity of 56 kilometres per second. For context, the recent January Quadrantids have a more sedate atmospheric impact velocity of 41 kilometres a second.

The unfolding 2014 drama of “Mars versus the Comet” will definitely be worth keeping an eye on… more to come!

Rosetta Is Happily Awake, But Comet Lander Will Slumber Until March

Artist's impression (not to scale) of the Rosetta orbiter deploying the Philae lander to comet 67P/Churyumov–Gerasimenko. Credit: ESA–C. Carreau/ATG medialab.

Now that Rosetta has (leisurely) arose from a 31-month slumber in space, the next step is to figure out how prepared the spacecraft is for its close encounter with a comet. Early indications show that the orbiting spacecraft is ready to go. Its lander, Philae, is still asleep and the plan isn’t to wake it up until March, ESA added.

In the initial wake-up stage for Rosetta, “We were most concerned about power, and seeing if the solar arrays were generating sufficient electricity to support the planned recommissioning activities,” stated Andrea Accomazzo, spacecraft operations manager. “But even though we were still 673 million km [418 million miles] from the Sun , we were getting enough power and the arrays appear to have come through hibernation with no degradation.”

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

Other systems are happily coming online as planned. Three of the four reaction wheels, which control Rosetta’s position in space, are working perfectly (with the fourth expected to be reactivated in a few weeks.) Next up is making sure Rosetta’s memory storage is working well enough to shelve science and operations information, and pinning down the spacecraft’s orbit.

So Rosetta is doing well after 31 months. With that hurdle leapt, technicians will begin to think about waking up Philae and making sure that its 10 instruments are working. By February, you can follow updates regularly on the Rosetta blog (as well as on Universe Today, of course!)

Rosetta should reach Comet 67P/Churyumov-Gerasimenko in August, and will start snapping pictures of the comet in May if all goes to plan. Astronomers are eager to see what the comet will teach us about the early years of the solar system, since comets are considered leftovers of when our neighborhood formed.

Source: ESA

Lovejoy and X1 LINEAR: How to See Comets That Will Warm Up Your Mid-Winter Mornings

Comet Lovejoy still shows both an ion tail (blue) and dust tail in this photo taken Jan. 12 from Stixendorf, Austria. Credit: Michael Jaeger

My hands are still cold from the experience, but there’s no denying the pleasure I felt at seeing C/2013 R1 Lovejoy and C/2012 X1 LINEAR through the telescope this morning.  Some comets fizzle, others fall apart, but these vaporous hunks have hung in there for months like steadfast friends that stick with you through hard times and good.While no longer visible with the naked eye, 50mm binoculars easily show it as a magnitude 7 fuzzy glow with a short, faint tail pointing up and away to the northwest.  I had no difficulty seeing it even with a last quarter moon glaring in the south.

Comets Lovejoy and X1 LINEAR are both moving across northern Ophiuchus. This map shows the sky facing east about 1 hour 45 minutes before sunrise shortly before the start of morning twilight. Detailed map below. Stellarium
Comets Lovejoy and X1 LINEAR are neighbors in northern Ophiuchus this month and next. This map shows the sky facing east about 1 hour 45 minutes before sunrise shortly before the start of morning twilight. Tick marks show the comets’ position every 5 days. Click to enlarge. Detailed map below. Created with Chris Marriott’s SkyMap software.

Rising around 3 a.m., Lovejoy is best placed for viewing just before the start of dawn when it climbs to about 30 degrees altitude in Ophiuchus. Lucky for us, Lovejoy will spend the next few mornings very close to the easy naked eye star 72 Ophiuchi, located 3 fists held at arm’s length to the lower right of brilliant Vega. It’s not often that a fairly bright comet passes this close to a helpful guide star. Don’t miss this easy catch. Soon the moon won’t be any trouble either as it skedaddles eastward and dwindles to a crescent in the coming mornings.

This deeper map shows stars to about magnitude 8. Although both comets appear to be getting lower every morning, the seasonal drift of the star to the west will keep them in good view for the next few months. Stellarium
This deeper map shows stars to about magnitude 8. Although both comets appear to be getting lower every morning, the westward seasonal drift of the stars will keep them in good view for the next few months. Click to enlarge. Created with Chris Marriott’s SkyMap software

Telescopic views of Lovejoy show a much diminished coma and tail compared to its heyday in early December. Still,  the nucleus remains bright and very condensed within the 3′ diameter gauzy coma; a faint and silky tail 2/3 of a degree long flowed across the field of view of my 15-inch (37-cm) reflector like a bride’s train. According to the excellent Weekly Information about Bright Comets site maintained by Seiichi Yoshida, Lovejoy should glow brighter than magnitude 8, what I consider the “bright” comet cutoff, through early February. Given that Lovejoy remains the brightest predicted comet visible till summer, show it some love the next clear night.

Comet C/2012 X1 LINEAR shows a green coma from fluorescing gases and a short tail in this photo made on Jan. 15, 2014. Credit: Rolando Ligustri
Comet C/2012 X1 LINEAR shows a green coma from fluorescing gases and a short tail in this photo made on Jan. 15, 2014. Credit: Rolando Ligustri

If Lovejoy’s a fading celebrity, X1 LINEAR suffered a mid-life crisis and snapped out of it with a whole new attitude.  Like Comet Holmes in 2007, it catapulted in brightness overnight in last October, blossoming from a 14th magnitude blip into a bright, expanding puffball briefly visible in ordinary binoculars. As expected, the comet soon faded. But on its return to obscurity,  X1 surprised again, re-brightening and growing a short tail. Now it’s humming along at 9th magnitude thank you very much. You’ll find it gliding across northern Ophiuchus not far from Lovejoy (more about that in a minute).

Very different appearance of C/2012 X1 LINEAR during outburst on Oct. 21, 2013. Credit: Ernesto Guido, Martino Nicolini & Nick Howes
Very different appearance of C/2012 X1 LINEAR during outburst on Oct. 21, 2013. Credit: Ernesto Guido, Martino Nicolini & Nick Howes

My binoculars won’t show the comet but a 6-inch telescope will do the trick. Overall weaker in appearance than Lovejoy, X1 LINEAR has a slightly larger, more diffuse coma,  brighter core and a short, faint tail pointing to the northwest. The comet will remain a fine target for smaller scopes through early March when it’s predicted to glow between magnitude 8 and 9.

Comets Lovejoy and X1 LINEAR will be closest together on the morning of Feb. 6 CST. Notice that they'll be in the company of numerous deep sky objects. Looks like a morning's worth of observing to me! Created with Chris Marriott's SkyMap software
Comets Lovejoy and X1 LINEAR will be closest together on the morning of Feb. 6 CST. A plethora of deep sky objects near them will make  for a complete morning’s worth of sky watching! Click to enlarge. Created with Chris Marriott’s SkyMap software

Looking at the maps, you’ll see that our two comets’ paths intersect. While they won’t overlap on the same morning, Lovejoy and X1 LINEAR will be in conjunction on Feb. 6 when they’ll be just 2 degrees apart. Get that camera ready! Guided telephoto and wide-field telescopes will be perfect for catching this unusual duet.

Before I sign off, don’t forget all the other good morning stuff: Mars hovers above Spica high in the south-southwestern sky, Saturn invites inspection in the southeast and Venus is back in view in the east-southeast 45 minutes before sunup. A delicate crescent moon shines near Venus on Jan. 28 and 29. Such riches.

After A Long Nap, NEOWISE Springs Into Action With Asteroid Discoveries

Dots (circled) in this image show the first asteroid spotted by NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) after the mission came out of hibernation. Credit: NASA

If anything, NASA’s asteroid-hunting spacecraft seems to be refreshed after going into forced hibernation for 2.5 years. In the first 25 days since it started seeking small solar system bodies in earnest again, the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) found three new objects and detected an additional 854, NASA said Thursday (Jan. 23).

Luckily for people interested in this field, Amy Mainzer (the principal investigator for this mission) has been tweeting out discoveries as they come — and other observations besides. “Just passed our @WISE_Mission post-restart review. I believe the technical term is “Yee haw!!” she wrote Jan. 21. Below are a couple of illustrated examples of discoveries from her Twitter feed. Click on the pictures for larger versions.

2014 AA53 NEOWISE

2014 AQ46 NEOWISE

In a release, NASA added that NEOWISE is “observing and characterizing” one NEO a day, which means not only looking at the object, but probing its size and composition. Astronomers know of about 10,500 NEOs, but of those only 10% (or about 1,500) have physical measurements cataloged as well. NEOWISE investigators aim to make hundreds of more of these measurements.

The mission (originally called WISE) launched in December 2009 to examine the universe in infrared light. After completely mapping the sky, it ran out of coolant it needed to do this work in 2010. It then shifted to examining comets and asteroids before being put into hibernation in February 2011. Read more about its mission history in this past Universe Today article.

Rosetta Wakes Up, Phones Home, Starts Tweeting

The Rosetta team at ESA’s space operations center in Darmstadt reacts after receiving a signal from the spacecraft. Credit: ESA.

The silence from the live video feed from the ESA’s space operations center in Darmstadt, Germany was almost deafening. Scientists and engineers were waiting to receive a signal from the Rosetta spacecraft, which was supposed to come out of hibernation today to begin its mission to Comet 67P/Churyumov-Gerasimenko in earnest. Finally, after waiting nearly 45 minutes into the window of time when the spacecraft was supposed to send a signal, a little blip appeared on the screens of the spectrum analyzers and the room erupted in cheers.

Data monitors from Rosetta showing the signal received back on Earth from the spacecraft. Credit: ESA.
Data monitors from Rosetta showing the signal received back on Earth from the spacecraft. Credit: ESA.

“After waiting over two and a half years, what is three-quarters of an hour!” said Fred Jansen, ESA’s Rosetta mission manager. “The spacecraft is there, it’s awake and the science team knows there are two busy years ahead of them. Now we have to work hard. Thanks to the team that achieved this.”

“I think I can speak on behalf of everyone here and everyone on Twitter: that was rather stressful!” said Matt Taylor, Rosetta project scientist. “The work begins now and I think we’ll have a fun-filled two years ahead, so let’s get on it!”

Soon after the signal arrived, the mission Twitter feed came alive, Tweeting “Hello World” in multiple languages.

Later in the day, as the team checked out the spacecraft, everything appeared in order and working well as systems began to start operating:

Rosetta was placed into hibernation in June 2011, with only the computer and several heaters remaining active as the spacecraft cruised out to nearly 800 million km from the warmth of the Sun, beyond the orbit of Jupiter.

Today, as Rosetta’s orbit came back to within 673 million km from the Sun, there was enough solar energy to power the spacecraft fully again and Rosetta’s pre-programmed internal ‘alarm clock’ woke up the spacecraft after a record 957 days of hibernation. After warming up its key navigation instruments, coming out of a stabilizing spin, and aiming its main radio antenna at Earth, Rosetta sent a signal to let mission operators know it had survived the most distant part of its journey.

The signal was received by NASA’s Goldstone ground station in California at 18:18 GMT during the first window of opportunity the spacecraft had to communicate with Earth.

The one-way light time on today, January 20, 2014 between Rosetta and Earth was about 44 minutes and 53 seconds over a distance of 807,224,610.74 km. Rosetta was about 9,188,540 km from the comet, closing up at about 800 m/second.

“This was one alarm clock not to hit snooze on, and after a tense day we are absolutely delighted to have our spacecraft awake and back online,” said Jansen.

Comets are considered the primitive building blocks of the Solar System and perhaps may have helped to ‘seed’ Earth with water, or even the ingredients for life. But many fundamental questions about these enigmatic objects remain, and through its comprehensive, in situ study of Comet 67P/Churyumov-Gerasimenko, Rosetta aims to unlock the secrets contained within.

“All other comet missions have been flybys, capturing fleeting moments in the life of these icy treasure chests,” said Taylor. “With Rosetta, we will track the evolution of a comet on a daily basis and for over a year, giving us a unique insight into a comet’s behavior and ultimately helping us to decipher their role in the formation of the Solar System.”

But first, essential health checks on the spacecraft must be completed. Then the eleven instruments on the orbiter and ten on the lander will be turned on and prepared for studying Comet 67P/Churyumov-Gerasimenko.

“We have a busy few months ahead preparing the spacecraft and its instruments for the operational challenges demanded by a lengthy, close-up study of a comet that, until we get there, we know very little about,” says Andrea Accomazzo, Rosetta operations manager.

Rosetta’s first images of 67P/Churyumov-Gerasimenko are expected in May, when the spacecraft is still 2 million km from its target. Towards the end of May, the spacecraft will execute a major maneuver to line up for its critical rendezvous with the comet in August.

After rendezvous, Rosetta will start with two months of extensive mapping of the comet’s surface, and will also make important measurements of the comet’s gravity, mass and shape, and assess its gaseous, dust-laden atmosphere, or coma. The orbiter will also probe the plasma environment and analyse how it interacts with the Sun’s outer atmosphere, the solar wind.

Using these data, scientists will choose a landing site for the mission’s 100 kg Philae probe. The landing is currently scheduled for November 11, 2014 and will be the first time that a landing on a comet has ever been attempted.

With almost negligible gravity from the comet’s 4 km-wide nucleus, Philae will have to use ice screws and harpoons to stop it from rebounding back into space after touchdown.

Among its wide range of scientific measurements, Philae will send back a panorama of its surroundings, as well as very high-resolution pictures of the surface. It will also perform an on-the-spot analysis of the composition of the ices and organic material, including drilling down to 23 cm below the surface and feeding samples to Philae’s on-board laboratory for analysis.

The focus of the mission will then move to the ‘escort’ phase, during which Rosetta will stay alongside the comet as it moves closer to the Sun, monitoring the ever-changing conditions on the surface as the comet warms up and its ices sublimate.

Rosetta will follow the comet throughout the remainder of 2015, as it heads away from the Sun and activity begins to subside.

You can read the team’s blog about the “wake up” here, and find out more about the Rosetta mission here.

Here’s a replay of the acquisition of signal: