Posted on by Bob King

New Images from Philae Reveal Comet’s Ancient Surface

First panorama sent by Philae from the surface of the comet. At upper right we see the reflection of the Sun and the top of the CONSERT instrument antenna. Credit: ESA

We may not know exactly where Philae is, but it’s doing a bang-up job sending its first photos from comet 67P/Churyumov-Gerasimenko. After bouncing three times on the surface, the lander is tilted vertically with one foot in open space in a “handstand” position.  When viewing the photographs, it’s good to keep that in mind. 

Philae landed nearly vertically on its side with one leg up in outer space. Here we see it in relation to the panoramic photos taken with the CIVA cameras. Credit: ESA
Philae landed nearly vertically on its side with one leg up in outer space. Here we see it in relation to the panoramic photos taken with the CIVA cameras. Credit: ESA

Although it’s difficult to say how far away the features are in the image. In an update today at a press briefing, Jean Pierre Biebring, principal investigator of CIVA/ROLIS (lander cameras), said that the features shown in the frame at lower left are about 1-meter or 3 feet away. Philae settled into its final landing spot after a harrowing first bounce that sent it flying as high as a kilometer above the comet’s surface.

After hovering for two hours, it landed a second time only to bounce back up again a short distance – this time 3 cm or about 1.5 inches. Seven minutes later it made its third and final landing. Incredibly, the little craft still functions after trampolining for hours!

Stephan Ulamec, Philae Lander manager, describes how Philae first landed less than 100 meters from the planned Agilkia site (red square). Without functioning harpoons and thrusters to fix it to the ground there, it rebounded and shot a kilometer above the comet. Right now, it's somewhere in the blue diamond. Credit: ESA
Stephan Ulamec, Philae Lander manager, describes how Philae first landed less than 100 meters from the planned Agilkia site (red square). Without functioning harpoons and thrusters to fix it to the ground there, it rebounded and shot a kilometer above the comet. Right now, it’s somewhere in the blue diamond. Credit: ESA

Despite its awkward stance, Philae continues to do a surprising amount of good science. Scientists are still hoping to come up with a solution to better orientate the lander. Their time is probably limited. The craft landed in the shadow of a cliff, blocking sunlight to the solar panels used to charge its  battery. Philae receives only 1.5 hours instead of the planned 6-7 hours of sunlight each day. That makes tomorrow a critical day.  Our own Tim Reyes of Universe Today had this to say about Philae’s power requirements:

Rosetta’s lander Philae is safely on the surface of Comet 67P/Churyumov-Gerasimenko, as these first two CIVA images confirm. One of the lander’s three feet can be seen in the foreground. The image is a two-image mosaic. Credit: ESA/Rosetta/Philae/CIVA
One of the lander’s three feet can be seen in the foreground in this high-resolution two-image mosaic. Credit: ESA/Rosetta/Philae/CIVA

“Philae must function on a small amount of stored energy upon arrival: 1000 watt-hours (equivalent of a 100 watt bulb running for 10 hours). Once that power is drained, it will produce a maximum of 8 watts of electricity from solar panels to be stored in a 130 watt-hour battery.” You can read more about Philae’s functions in Tim’s recent article.

Ever inventive, the lander team is going to try and nudge Philae into the sunlight by operating the moving instrument called MUPUS tonight. The operation is a delicate one, since too much movement could send the probe flying off the surface once again.

Here are additional photos from the press conference showing individual segments of the panorama and other aspects of Philae’s next-to-impossible landing. As you study the crags and boulders, consider how ancient this landscape is. 67P originated in the Kuiper Belt, a large reservoir of small icy bodies located just beyond Neptune, more than 4.5 billion years ago. Either through a collision with another comet or asteroid, or through gravitational interaction with other planets, it was ejected from the Belt and fell inward toward the Sun.

Astronomers have analyzed its orbit and discovered that up until 1840, the future comet 67P never came closer than 4 times Earth’s distance from the Sun, ensuring that its ices remained as pristine as the day they formed. After that date, the comet passed near Jupiter and its orbit changed to bring it within the inner Solar System. We’re seeing a relic, a piece of dirty ice rich with history. Even a Rosetta stone of its own we can use to interpret the molecular script revealing the origin and evolution of comets.

Philae falls to the craggy comet photographed by the Rosetta mothership. Credit: ESA
Philae falls to the craggy comet photographed by the Rosetta mothership. Credit: ESA
An image of Comet 67P/Churyumov–Gerasimenko at less than 10 km from its surface. This selection of previously unpublished ‘beauty shots’, taken by Rosetta’s navigation camera, presents the varied and dramatic terrain of this mysterious world from this close orbit phase of the mission. Credit: ESA.
An image of Comet 67P/Churyumov–Gerasimenko at less than 10 km from its surface. This selection of previously unpublished ‘beauty shots’, taken by Rosetta’s navigation camera, presents the varied and dramatic terrain of this mysterious world from this close orbit phase of the mission. Credit: ESA.
Frame from panoramic image. Credit: ESA
Frame from panoramic image. This has been heavily toned to reveal details in the shadow of the cliff. Credit: ESA
Frame from panoramic image. Credit: ESA
Frame from panoramic image. Credit: ESA
Frame from panoramic image. Credit: ESA
Frame from panoramic image. Credit: ESA
Frame from panoramic image. Credit: ESA
Frame from panoramic image. Credit: ESA
Frame from panoramic image. Credit: ESA
Frame from panoramic image. Credit: ESA
Image from the Philae lander as it approached the surface. The dust-covered boulder at upper right is about 5 meters (16.4 feet) across. The dust might have originated through vaporization of ice on the boulder itself or deposited there by dust settling from jets elsewhere. Credit: ESA
Image from the Philae lander as it approached the surface. The dust-covered boulder at upper right is about 5 meters (16.4 feet) across. The dust might have originated through vaporization of ice in the boulder itself or settled there from active jets elsewhere on the comet. Credit: ESA

 

Posted on by Bob King

We Land on a Comet Today! Updates on Philae’s Progress

Just released "farewell photo" taken by the Philae lander as it departed Rosetta around 2:30 a.m. (CST) today. It shows the one of the solar arrays. Credit: ESA/Rosetta/Philae/CIVA

Anticipation is intense as the Philae lander free-falls to the surface of Comet Churyumov-Gerasimenko this morning. The final “Go” for separation from the Rosetta spacecraft was given around 2:30 a.m.; Philae’s now well on its way to Agilkia, the target landing site atop the 67P/C-G’s largerEverything is running smoothly except for one potential problem. During checks on the lander’s health, it was discovered that the active descent system, which provides a thrust to avoid rebound at the moment of touchdown, can’t be activated.

Artist impression of Philae separating from Rosetta earlier this morning. The lander is now free-falling to the comet under the influence of its gravity. Credit: ESA
Artist impression of Philae separating from Rosetta earlier this morning. The lander is now free-falling to the comet under the influence of its gravity. Credit: ESA

At touchdown, as Philae anchors itself to the comet with harpoons and ice screws on each of its legs, the thruster on top of the lander is supposed to push it down to counteract the force of the harpoon firing in the opposite direction.

Klim Churyumov (left) Svetlana Gerasimenko are both at ESA today during the historic landing on the comet they discovered on September 20, 1969. Credit: ESA TV
Klim Churyumov (left) Svetlana Gerasimenko are both at ESA today during the historic landing on the comet they discovered on September 20, 1969. Credit: ESA TV

“The cold gas thruster on top of the lander does not appear to be working so we will have to rely fully on the harpoons at touchdown,”says Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.

The Philae that could! The lander photographed during its descent by Rosetta. Credit: ESA/Rosetta/MPS for Rosetta Team/
The Philae that could! The lander photographed during its descent by Rosetta. Credit: ESA/Rosetta/MPS for Rosetta Team/

Philae is on target to land on the comet around 9:37 a.m. CST (15:37 UT). Confirmation of touchdown will take about 28 minutes as the signal, traveling at the speed of light, works its way back on Earth. As Philae floats down to the comet it not only has to deal with the 67P/C-G’s gravity but also the cloud of dust and ice grains escaping from the surface. Check back for regular updates and photos!

Tense control room during the Philae landing confirmation. Credit: ESA
Tense control room during the Philae landing confirmation Time: 9:48 a.m. CST. Credit: ESA
Posted on by Tim Reyes

Philae Ready to Take Flying Leap to Historic Comet Landing (Coverage Information)

After a ten year journey that began with the launch from the jungles of French Guyana, landing Philae is not the end of mission, it is the beginning of a new phase. A successful landing is not guaranteed but the ESA Rosetta team is now ready to release Philae on its one way journey. (Photo Credits: ESA/NASA, Illustration: J.Schmidt)

We are now in the final hours before Rosetta’s Philae lander is released to attempt a first-ever landing on a comet. At 9:03 GMT (1:03 AM PST) on Wednesday, November 12, 2014, Philae will be released and directed towards the surface of comet 67P/Churyumov–Gerasimenko. 7 hours later, the lander will touch down.

Below you’ll find a timeline of events, info on how to watch the landing, and an overview of how the landing will (hopefully) work.

In human affairs, we build contingencies for missteps, failures. With spacecraft, engineers try to eliminate all single point failures and likewise have contingency plans. The landing of a spacecraft, be it on Mars, Earth, or the Moon, always involves unavoidable single point failures and points of no return, and with comet 67P/Churyumov–Gerasimenko, Rosetta’s Philae lander is no exception.

Rosetta’s and Philae’s software and hardware must work near flawlessly to give Philae the best chance possible of landing safely. And even with flawless execution, it all depends on Philae’s intercepting a good landing spot on the surface. Philae’s trajectory is ballistic on this one way trip to a comet’s surface. It’s like a 1 mile per hour bullet. Once fired, it’s on its own, and for Philae, its trajectory could lead to a pristine flat step or it could be crevasse, ledge, or sharp rock.

Live European Space Agency Coverage also Main Page Live Feed

Watch ESA’s live feed:

The accuracy of the landing is critical but it has left a 1 square kilometer of uncertainty. For this reason, engineers and scientists had to survey the whole surface for the most mild features. Comet 67P has few areas that are not extreme in one way or another. Site J, now called Agilkia, is one such site.

When first announced in late September, the time of release was 08:35 GMT (12:35 AM PST). Now the time is 9:03 GMT. The engineers and computer scientists have had six weeks to further refine their trajectory. It’s a complicated calculation that has required running the computer simulation of the descent backwards. Backwards because they can set a landing time then run Philae backwards to the moment of release. The solution is not just one but many, thousands or millions if you want to look in such detail. With each release point, the engineers had to determine how, or if, Rosetta could be navigated to that coordinate point in space and time.

Arrival time of the radio signal with landing status: 16:30 GMT

Rosetta/Philae at 500 million km [320 million miles], 28.5 minutes light time

Arrival of First Images: 06:00 GMT, November 13, 2014

The gravity field of the comet is so weak, it is primarily the initial velocity from Rosetta that delivers Philae to the surface. But the gravity is there and because of the chaotic shape and unknown (as yet) mass distribution inside, the gravity will make Philae move like a major league knuckleball wobbling to the plate and a batter. Furthermore, the comet during the  seven hour trip will make half a rotation. The landing site will not be in site when Philae is released.

And as Philae is on final approach, it will use a small rocket not to slow down but rather thrust it at the comet, landing harpoons will be fired, foot screws will try to burrow into the comet, and everyone on Earth will wait several minutes for a message to be relayed from Philae to Rosetta to the Deep Space Network (DSN) antennas on Earth. Philae will be on its own as soon as it leaves Rosetta and its fate is a few hours away.

Why travel to a comet? Comets represent primordial material leftover from the formation of the solar system. Because cometary bodies were formed and remained at a distance from the heat of the sun, the materials have remained nearly unchanged since formation, ~4.5 billion years ago. By looking at Rosetta’s comet, 67P/Churyumov–Gerasimenko, scientists will gain the best yet measurements of a comet’s chemical makeup, its internal structure created during formation, and the dynamics of the comet as it approaches the warmth of the Sun. Theories propose that comets impacting on Earth delivered most of the water of our oceans. If correct, then we are not just made of star-stuff, as Carl Sagan proclaimed, we are made of comet stuff, too. Comets may also have delivered the raw organic materials needed to start the formation of life on Earth.

Besides the ESA live feeds, one can take a peek at NASA’s Deep Space Network (DSN) at work to see which telescopes are communicating with Rosetta. JPL’s webcast can watched below:



Broadcast live streaming video on Ustream

Past Universe Today Articles on the Rosetta Mission:

A Comet’s Tale – Rosetta’s Philae, Five Days from Touchdown
Stinky! Rosetta’s Comet Smells Like Rotten Eggs And Ammonia
Why Watch ESA Rosetta’s Movie ‘Ambition’? Because We Want to Know What is Possible
Rosetta’s Philae Lander: A Swiss Army Knife of Scientific Instruments
ESA’s Rosetta Mission sets November 12th as the Landing Date for Philae
Creepy Comet Looms In The Background Of Newest Philae Spacecraft Selfie
How Do You Land on a Comet? Very Carefully.
How Rosetta Will Send Philae Lander To Comet’s Surface (Plus, Landing Site Contest!)
Spider-Like Spacecraft Aims To Touch A Comet Next Year After Rosetta Reactivates
Rosetta’s Comet Springs Spectacular Leaks As It Gets Closer To The Sun
How Dust Lightens Up The ‘Dark Side’ Of Rosetta’s Comet
It’s Alive! Rosetta’s Comet Flares As It Approaches The Sun

References:

Why visit a comet, University of Leicester, Planetary Scientist explains

Posted on by Elizabeth Howell

Incredible Snow-Dragging Spaceship Landing From The Space Station

Tracks in the snow mark Expedition 41's landing from the space station Nov. 9, 2014. Credit: NASA/Bill Ingalls

Check out that landing mark! A Soyuz spacecraft carrying three people touched down safely in remote Kazakhstan late Sunday (EDT) and went for a brief sleigh ride in the snow, as you can see from the drag marks on the landscape.

The flawless landing included the Expedition 40/41 crew members of Reid Wiseman (NASA), Alexander Gerst (European Space Agency) and Maxim Suraev (Roscosmos), who spent 165 days in space, mainly living on the International Space Station. Check out some more landing pictures and video below.

Alexander Gerst, an astronaut from the European Space Agency, does a fist pump shortly after the safe Expedition 41 landing Nov. 9, 2014. Credit: ESA–S. Corvaja, 2014
Alexander Gerst, an astronaut from the European Space Agency, does a fist pump shortly after the safe Expedition 41 landing Nov. 9, 2014. Credit: ESA–S. Corvaja, 2014

Posted on by Markus Pössel

How Does Rosetta’s Comet Compare with Alpine Mountains?

There have been some cool visualizations showing the size of the nucleus of the target comet of ESA’s Rosetta mission – where the Philae lander will attempt to land on November 12. One shows the nucleus on the ground in Los Angeles, another has it looming as a dark mountain over Manhattan, and yet another has its silhouette superimposed onto the City of London.

On a hiking holiday in the Swiss Alps this summer, it struck me that an Alpine setting — or its equivalent in other countries – looking at kilometer-sized objects at distances up to a dozen or dozens of kilometers is probably the situation where we can best develop an intuition about just how large the nucleus of 67P/Churyumov–Gerasimenko is.

Today, I took the time to insert the nucleus in one of my holiday snaps, using one of the Rosetta Navcam images that ESA has just released under a Creative Commons license. My original image was taken from a hiking trail between the Swiss villages of Bettmeralp and Fiescheralp, looking South-East towards Italy. The first image, above, has the comet floating just behind the first mountain range in the Binntal valley.

This is a fairly big sucker, even compared with the mountains in front and behind. In this image, the cometary nucleus is at a distance of about 7.2 kilometers (4.3 miles) from the observer.

I’ve also set the nucleus a bit farther back: Just beyond the most distant mountain range dominating the center of the image, which includes Italy’s Mount Cervandone, 3210 meters (10,530 ft.) high. It’s sitting right beyond the most distant mountain range visible in the original image (at a distance of about 14 km [8.7 mi] from the observer), and still looks fairly impressive:

67P-cervandone-mpoessel
Image credit: M. Pössel/HdA using an image from ESA/Rosetta/NAVCAM. Released under CC BY-SA IGO 3.0

And this, I guess, makes a cometary nucleus a nice link between the terrestrial and the cosmic: It is comparable to the largest structures we can directly see here on Earth, and does not have the enormous (astronomical!) dimensions so often encountered in space, whose size we cannot directly imagine.

On November 12, we’ll hopefully have another comparison: How will the view transmitted by the Philae lander correspond to terrestrial landscapes? What impression of size will we get then? Good luck, Rosetta and Philae!

Production notes

The images were made from two images shot with a Canon 70D with the standard kit lens – one showing the landscape, and a separate one showing more suitable sky and clouds on a different day, in a different location. Using Gimp, I inserted a fairly well-known Navcam image from ESA’s Flickr collection. The image came with the information that its resolution was 5.3 m per pixel; I used this plus distance information from Google Maps and elevation information via Mapcoordinates, combined with a test image giving me my camera’s pixel scale, to estimate the appropriate size of the cometary nucleus in the image (no lens distortion; camera modeled as a simple pinhole camera).

 

Posted on by Tim Reyes

A Comet’s Tale – Rosetta’s Philae, Five Days from Touchdown

Rosetta, the scientific mission to explore a comet's surface. "Ambition", a short Sci-Fi film, set in the near future, and Rosetta, the children's fable, to encourage the next generations to undertake on the great adventures still to come. (Photo Credits: ESA, Platige Image, ESA Communications)

In the recently released Rosetta short film called “Ambition”, the master begins a story to his apprentice – “Once upon a time.” The apprentice immediately objects to his triteness. But he promises that it is worth the slight tribulation. Who could have imagined ten years ago that Rosetta would become so successful in two such contrasting approaches to telling a tale.

The Rosetta mission is part franchise and part scientific mission. In five days, Rosetta will reach a crossroad, a point of no return as epic as moments in Harry Potter or Lord of the Rings. A small mindless little probe called Philae will be released on a one-way trip to the surface of a comet. Win or lose, Philae will live on in the tale of a comet and a mission to uncover the mysteries of our planet’s formation.

ESA did not promise a good mission as Aidan Gillen promises a good story in Ambition. A space mission is never put in terms of a promise but rather it is thousands of requirements and constraints that formulate a mission plan and a spacecraft design. The European Space Agency put 1 billion Euros ($1.3 billion) to work and did so in what now looks like one of the greatest space missions of the first century of space exploration.

The Rosetta mission is actually two missions in one. There is the comet chaser, the orbiter – Rosetta and then the lander Philae. The design of Rosetta’s objectives is some part, probably in large part, was conceived by dismissing the presence of Philae. Make a space probe to a comet that just orbits the small body. Select your scientific instrumentations accordingly. Now add a small lander to the mission profile that will do something extraordinary – what Rosetta cannot do with its instrumentation. Finally, make sure that Rosetta has everything needed to support Philae’s landing on a comet.

Here is what they have as the game plan on November 12th (the sequence of events begins while its still November 11th in the Americas). These two times are absolutely non- trivial. They are finely tuned to a timepiece called  67P/Churyumov–Gerasimenko. If calculations were made in error, then Philae’s ultimate fate is unknown. Start exactly on time and Philae will be given the best chance at making a successful  touchdown on the comet.

Separation of Philae from Rosetta:   09:03 GMT (10:03 CET)

Touchdown on the comet:                    16:02 GMT (17:02 CET).

During this time, comet  67P/Churyumov–Gerasimenko will complete over half a rotation on its axis. To be exact, it will rotate 56.2977% of a full rotation. Comet 67P will have its back turned towards Rosetta as it holds the diminutive Philae for the last time and releases Philae for the first and only time.

Now that the ESA, with help from the graphic artists from Platige Image from Poland, has released something entertaining for the science fiction minded among us, they have again released a next episode in their children’s fable of Rosetta and Philae (video below). This cartoon of the final moments of Rosetta and Philae together preparing for the descent which could well be the final moments of Philae.

Philae could fail, crack like an egg on a sharp rock or topple over a cliff or into a crevasse on the surface of 67P. What happens to Philae will make for a Grimm’s fairy tale ending or something we would all prefer. In either case, the ESA is using graphic arts and storytelling to inspire the next generations to join in what our JFK called “great adventures of all time” [ref].

Through a contest something NASA and JPL have used several times to involve the public, the ESA asked the public to come up with a name for the landing site, site J. Out of the thousands of entries, 150 people suggested the name Agilkia [ref]. Alexandre Brouste from France, the designated winner, has been invited to watch the landing activities at Rosetta’s mission control in Darmstadt, Germany. It follows from the Eqyptian theme of the mission’s two probes. “Rosetta” comes from the clay tablet discovered in the 1800s that led to the deciphering of Egyptian hieroglyphics. Philae” is a island on the Nile which held magnificent Eqyptian temples. With the operation  of the Aswan dam starting in 1902, the island of Philae was repeatedly flooded and the temple was at risk. UNESCO beginning in 1960 started a project to save the islands historic structures. They were all moved to a nearby Nile island called Agilkia [related U.T. article]. This becomes a part of the Rosetta story – a lander named Philae in reference to the obelisks used along with the Rosetta stone to decipher Eqyptian writings, departing its mother ship on a short but critical voyage to a final resting place, the landing site now called Agilkia.

Upon landing, a landing confirmation signal is expected from Philae via Rosetta at about 8:02 AM PST (11:02 AM EST, 17:02 Central European Time). Alexandre Brouste of France, the designated winner of the landing site naming contest will be in Darmstadt, Germany in mission control to watch the landing unfold with the Rosetta engineers and scientists. Surely, millions of citizens of the European Union and people worldwide will be watching via the World Wide Web.

The timeline and events to unfold as Philae, the lander is released from Rosetta, the comet orbiter. (Illustration Credit: ESA)
The timeline and events to unfold as Philae, the lander is released from Rosetta, the comet orbiter. (Illustration Credit: ESA)

Previous Rosetta and Philae articles at Universe Today

Rosetta’s Philae Lander: A Swiss Army Knife of Scientific Instruments

Why Watch ESA Rosetta’s Movie ‘Ambition’? Because We Want to Know What is Possible

Posted on by Jason Major

Will Gaia Be Our Next Big Exoplanet Hunter?

ESA's Gaia is currently on a five-year mission to map the stars of the Milky Way. Image credit: ESA/ATG medialab; background: ESO/S. Brunier.

Early on the morning of Dec. 19, 2013, the pre-dawn sky above the coastal town of Kourou in French Guiana was briefly sliced by the brilliant exhaust of a Soyuz VS06 rocket as it ferried ESA’s “billion-star surveyor” Gaia into space, on its way to begin a five-year mission to map the precise locations of our galaxy’s stars. From its position in orbit around L2 Gaia will ultimately catalog the positions of over a billion stars… and in the meantime it will also locate a surprising amount of Jupiter-sized exoplanets – an estimated 21,000 by the end of its primary mission in 2019.

And, should Gaia continue observations in extended missions beyond 2019 improvements in detection methods will likely turn up even more exoplanets, anywhere from 50,000 to 90,000 over the course of a ten-year mission. Gaia could very well far surpass NASA’s Kepler spacecraft for exoplanet big game hunting!

“It is not just the number of expected exoplanet discoveries that is impressive”, said former mission project scientist Michael Perryman, lead author on a report titled Astrometric Exoplanet Detection with Gaia. “This particular measurement method will give us planet masses, a complete exoplanet survey around all types of stars in our Galaxy, and will advance our knowledge of the existence of massive planets orbiting far out from their host stars”.

Watch: ESA’s Gaia Launches to Map the Milky Way

Artist's impression of a Jupiter-sized exoplanet orbiting an M-dwarf star
Artist’s impression of a Jupiter-sized exoplanet orbiting an M-dwarf star

The planets Gaia will be able to spot are expected to be anywhere from 1 to fifteen times the mass of Jupiter in orbit around Sun-like stars out to a distance of about 500 parsecs (1,630 light-years) from our own Solar System. Exoplanets orbiting smaller red dwarf stars will also be detectable, but only within about a fifth of that distance.

While other space observatories like NASA’s Kepler and CNES/ESA’s CoRoT were designed to detect exoplanets through the transit method, whereby a star’s brightness is dimmed ever-so-slightly by the silhouette of a passing planet, Gaia will detect particularly high-mass exoplanets by the gravitational wobble they impart to their host stars as they travel around them in orbit. This is known as the astrometric method.

A select few of those exoplanets will also be transiting their host stars as seen from Earth – anywhere from 25 to 50 of them – and so will be observable by Gaia as well as from many ground-based transit-detection observatories.

Read more: Gaia is “Go” for Science After a Few Minor Hiccups

After some issues with stray light sneaking into its optics, Gaia was finally given the green light to begin science observations at the end of July and has since been diligently scanning the stars from L2, 1.5 million km from Earth.

With the incredible ability to measure the positions of a billion stars each to an accuracy of 24 microarcseconds – that’s like measuring the width of a human hair from 1,000 km – Gaia won’t be “just” an unprecedented galactic mapmaker but also a world-class exoplanet detector! Get more facts about the Gaia mission here. 

The team’s findings have been accepted for publication in The Astrophysical Journal.

Source: ESA

Posted on by Elizabeth Howell

How Dust Lightens Up The ‘Dark Side’ Of Rosetta’s Comet

This "dark side" image of Comet 67P/Churyumov-Gerasimenko shows light backscattered from dust particles in the coma surrounding the comet, which helps scientists search for surface features. The picture was taken by the Rosetta spacecraft Sept. 29 from about 19 kilometers (12 miles). Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

How do you see a side of a comet that is usually shrouded in darkness? For the plucky scientists using the Rosetta spacecraft, the answer comes down to using dust to their advantage. They’re trying to catch a glimpse of the shadowed southern side using light scattering from dust particles in anticipation of watching the comet’s activity heat up next year.

Using Rosetta’s OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) instrument, scientists are diligently mapping Comet 67P/Churyumov-Gerasimenko’s surface features as it draws closer to the Sun. Funny enough, the shadowed side will be in full sunlight by the time the comet gets to its closest approach. This gives scientists more incentive to see what it looks like now.

The comet side is in shadow because its is not perpendicular to its orbital plane, the Max Planck Institute for Solar System Research stated. This means that areas of the comet can stay in shadow for months at a time. But using OSIRIS’ powerful receptors, scientists can get a few hints about what those surface features are, using dust scattering.

Playing with saturation levels in these images, scientists using the Rosetta's spacecraft imaging system are able to get more information about surface features in the image at right. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Playing with saturation levels in these images, scientists using the Rosetta’s spacecraft imaging system are able to get more information about surface features in the image at right. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

“For a normal camera, this tiny bit of scattered light would not help very much”, stated OSIRIS team member Maurizio Pajola from the University of Padua in Italy. A normal camera has eight bits per pixel of information (256 shades of gray), while OSIRIS’ 16 bits allow it to distinguish between 65,000 shades. “In this way, OSIRIS can see black surfaces darker than coal together with white spots as bright as snow in the same image,” he added.

The scientists were not specific in a press release about what they are seeing so far, but they said that in May 2015 they expect to get a lot more data very quickly — once the area goes into full sunlight.

Rosetta, a mission of the European Space Agency, has been orbiting the comet since August. Next Wednesday it will release a lander, Philae, that will attempt to make the first soft landing on a comet’s surface.

Source: Max Planck Institute for Solar System Research

Posted on by Elizabeth Howell

Satellite Debris Forces Space Station To Evade Threat Hours Before Collision Risk

The International Space Station as seen by the departing STS-134 crew on May 29, 2011. Credit: NASA

A spacecraft attached to the International Space Station did an “emergency maneuver” to push the complex, which now houses six people, away from a threatening piece of space debris Oct. 27, the European Space Agency said in a statement.

A hand-sized shard of the Russian Cosmos-2251 satellite, which collided with a U.S. Iridium satellite in 2009, would have come within at least four kilometers (2.5 miles) of the orbiting outpost. This was close enough for the space station partners to agree to a move six hours before the potential impact.

“This is the first time the station’s international partners have avoided space debris with such urgency,” the European Space Agency wrote. The push to a safer orbit took place using the agency’s automated transfer vehicle Georges Lemaître, which docked with the space station in August.

The International Space Station in October 2014, with the European automated transfer vehicle Georges Lemaître attached. Credit: Alexander Gerst/ESA/NASA
The International Space Station in October 2014, with the European automated transfer vehicle Georges Lemaître attached. Credit: Alexander Gerst/ESA/NASA

While many collision threats are spotted at least days before impact, occasionally ground networks aren’t able to see a piece until 24 hours or less before the potential impact. Since 2012, the space station has normally done last-minute maneuvers using Russian cargo Progress vehicles, but this time around none were docked there. This is where the ATV came in.

Controllers at the ATV control center in France then did a four-minute preprogrammed move that raised the station’s orbit by one kilometer (0.6 miles), enough to get out of the way.

The ATV is expected to remain at the station until February, when it will undock and burn up in the atmosphere. This is the last of the series of ATVs that Europe agreed to make as a part of its space station agreement.

Posted on by Tim Reyes

A History of Launch Failures: “Not Because They are Easy, but Because They are Hard”

The Rice Speech words hold especially true when the NASA's goals seem challenged and suddenly not so close at hand. (Photo Credit: NASA)

Over the 50-plus years since President John F. Kennedy’s Rice University speech, spaceflight has proven to be hard. It doesn’t take much to wreck a good day to fly.

Befitting a Halloween story, rocket launches, orbital insertions, and landings are what make for sleepless nights. These make-or-break events of space missions can be things that go bump in the night: sometimes you get second chances and sometimes not. Here’s a look at some of the past mission failures that occurred at launch. Consider this a first installment in an ongoing series of articles – “Not Because They Are Easy.”

A still image from one of several videos of the ill-fated Antares launch of October 28, 2014, taken by engineers at the Mid-Atlantic Regional Spaceport, Wallops, VA. (Credit: NASA)
A still image from one of several videos of the ill-fated Antares launch of October 28, 2014, taken by engineers at the Mid-Atlantic Regional Spaceport, Wallops, VA. (Credit: NASA)

The evening of October 28, 2014, was another of those hard moments in the quest to explore and expand humanity’s presence in space. Ten years ago, Orbital Sciences Corporation sought an engine to fit performance requirements for a new launch vehicle. Their choice was a Soviet-era liquid fuel engine, one considered cost-effective, meeting requirements, and proving good margins for performance and safety. The failure of the Antares rocket this week could be due to a flaw in the AJ-26 or it could be from a myriad of other rocket parts. Was it decisions inside NASA that cancelled or delayed engine development programs and led OSC and Lockheed-Martin to choose “made in Russia” rather than America?

Here are other unmanned launch failures of the past 25 years:

Falcon 1, Flight 2, March 21, 2007. Fairings are hard. There are fairings that surround the upper stage engines and a fairing covering payloads.  Fairings must not only separate but also not cause collateral damage. The second flight of the Falcon 1 is an example of a 1st stage separation and fairing that swiped the second stage nozzle. Later, overcompensation by the control system traceable to the staging led to loss of attitude control; however, the launch achieved most of its goals and the mission was considered a success. (View: 3:35)

Proton M Launch, Baikonur Aerodrome, July 2, 2013. The Proton M is the Russian Space program’s workhorse for unmanned payloads. On this day, the Navigation, Guidance, and Control System failed moments after launch. Angular velocity sensors of the guidance control system were installed backwards. Fortunately, the Proton M veered away from its launch pad sparing it damage.

Ariane V Maiden Flight, June 4, 1996. The Ariane V was carrying an ambitious ESA mission called Cluster – a set of four satellites to fly in tetrahedral formation to study dynamic phenomena in the Earth’s magnetosphere. The ESA launch vehicle reused flight software from the successful Ariane IV. Due to differences in the flight path of the Ariane V, data processing led to a data overflow – a 64 floating point variable overflowing a 16 bit integer. The fault remained undetected and flight control reacted in error. The vehicle veered off-course, the structure was stressed and disintegrated 37 seconds into flight. Fallout from the explosion caused scientists and engineers to don protective gas masks. (View: 0:50)

Delta II, January 17, 1997. The Delta II is one of the most successful rockets in the history of space flight, but not on this day. Varied configurations change up the number of solid rocket motors strapped to the first stage. The US Air Force satellite GPS IIR-1 was to be lifted to Earth orbit, but a Castor 4A solid rocket booster failed seconds after launch. A hairline fracture in the rocket casing was the fault. Both unspent liquid and solid fuel rained down on the Cape, destroying launch equipment, buildings, and even parked automobiles. This is one of the most well documented launch failures in history.

Compilation of Early Launch Failures. Beginning with several of the early failures of Von Braun’s V2, this video compiles many failures over a 70 year period. The early US space program endured multiple launch failures as they worked at a breakneck speed to catch up with the Soviets after Sputnik. NASA did not yet exist. The Air Force and Army had competing designs, and it was the Army with the German rocket scientists, including Von Braun, that launched the Juno 1 rocket carrying Explorer 1 on January 31, 1958.

One must always realize that while spectacular to launch viewers, a rocket launch has involved years of development, lessons learned, and multiple revisions. The payloads carried involve many hundreds of thousands of work-hours. Launch vehicle and payloads become quite personal. NASA and ESA have offered grief counseling to their engineers after failures.

“We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.”

Kennedy’s Rice University Speech, September 12, 1962