The search for the Philae lander on Comet 67P/C-G

Here is a reprint of an article from the Rosetta mission team on where the lander might be:

Where is Philae? When will it wake up?



Where is Philae?

Ever since Philae touched down on Comet 67P/Churyumov-Gerasimenko for the final time on 12 November – it is thought to have come into contact with the comet’s surface a total of four times including the final landing – the search has been on to identify it in images. While the CONSERT instrument has helped to narrow down a 350 x 30 m ‘landing strip’ on Comet 67P/C-G’s smaller lobe, a dedicated search in OSIRIS images has so far not been able to confirm the little lander’s final location.

Philae’s descent to the surface, the initial touchdown at Agilkia at 15:34 UT (onboard spacecraft time) and first rebound were well-documented with the OSIRIS narrow-angle camera. The team also identified what they believe to be the lander in a wide-angle shot taken at 17:18 UT above the rim of the large depression – named Hatmehit – on the comet’s small lobe. The image has been used to guide subsequent lander search efforts, and provides the basis for trajectory reconstructions. According to data recorded by Philae’s ROMAP instrument, the lander may have grazed the surface at 16:20 UT – so this image may have captured the result of that encounter.

Philae_above_the_comet_node_full_image_2[1]Philae above the comet?
Rosetta’s OSIRIS wide-angle camera captured this view of
Comet 67P/Churyumov–Gerasimenko on 12 November 2014
at 17:18 GMT (onboard spacecraft time). Marked is what the OSIRIS
team believe to be the Philae lander above the rim of the large
depression – named Hatmehit – on the comet’s small lobe. The
image has been used to guide subsequent lander search efforts,
and provides the basis for trajectory reconstructions.
Credits: ESA/Rosetta/MPS for OSIRIS Team

Philae’s onboard data subsequently recorded the next touchdown at 17:25 UT and its final touchdown at 17:32 UT, at a site that has now been named “Abydos” (the first touchdown site remains as Agilkia). Images sent back by the CIVA imager onboard the lander and subsequent reconstructions are providing clues as to the nature of the landing site, but a visual confirmation is still required to confirm its location.

Follow-up dedicated OSIRIS imaging campaigns that took place in late November and December from distances of 30 and 20 km from the centre of the comet (about 28 and 18 km from the surface, respectively) have not been successful in locating the lander. The campaigns specifically targeted the times that the lander would be illuminated – it is illuminated approximately 1.3 hours per comet revolution – and that Rosetta had the correct orbital position to be able to image it. However, the cameras were looking into long cast shadows from Rosetta’s terminator orbit, perpendicular to the Sun direction, which does not provide the optimum conditions for detecting the lander.

It is also important to note that Rosetta’s trajectory immediately following Philae’s touchdown allowed for good viewing conditions at the original landing site. Now that Rosetta has moved to a different orbit, and is further away from the comet, the chances of observing the lander are less (watch this video for a recap of the different trajectories following the landing).

The image below is an example of the images being used to search for the lander; it is a slightly cropped 2 x 2 mosaic taken by the OSIRIS narrow-angle camera on 13 December 2014 from a distance of about 20 km to the centre of the comet. For the 20 km imaging run 18 sets of two images were taken – one each with orange and blue filters to take advantage of the reflection of the lander solar panels, which differ compared to the cometary environment. The images were taken in the 2 x 2 rasters to ensure good surface coverage. The lander, about 1 metre across – the size of a household washing machine – would measure only about three pixels across in these images.

Lander_search_area_node_full_image_2[1]Lander search area
An example of the OSIRIS narrow-angle camera mosaics being used to search
for Rosetta’s lander, Philae. The image is a slightly cropped 2 x 2 mosaic
comprising images taken on 13 December 2014 from a distance of about
20 km to the centre of the comet. The lander, about 1 m across –
the size of a household washing machine – would measure only about
three pixels across in these images. The team are searching – by eye – for a
set of three spots that correspond to the lander shape, but with the region
strewn with boulders it is soon easy to identify multiple sets of three spots.
Credits: ESA/Rosetta/MPS for OSIRIS Team

“We’re looking – by eye – for a set of three spots that correspond to the lander,” says OSIRIS principal investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. “The problem is that sets of three spots are very common all over the comet nucleus; Hatmehit and the area around its rim where we’re looking is full of boulders and we have identified several sets of three spots.”

Although Rosetta is flying to within 6 km of the comet’s surface on 14 February, the planned trajectory foresees the closest approach on the lower part of the larger comet lobe (although the trajectory also takes Rosetta over the first touchdown point). This trajectory is planned such that the Sun will be directly behind the spacecraft, allowing the acquisition of shadow-free images. The close flyby will also allow the suite of science instruments on the orbiter to take spectra of the surface with unprecedented resolution and to directly sample the very innermost regions of the cometary coma in order to learn more about how the comet’s characteristic coma and tail develop.

“Rosetta’s busy science schedule is planned several months in advance, so a dedicated Philae search campaign was not built into the plan for the close flyby,” says ESA’s Rosetta project scientist Matt Taylor. “We’ll be focusing on “co-riding” observations from now on, that is, we won’t be changing the trajectory of Rosetta to specifically fly over the predicted landing zone in a dedicated search, but we can modify the spacecraft pointing and/or command images to be taken of the region if we’re flying close to the region and the science operations timeline allows.”

“After the flyby we’ll be much further away from the comet again, so are unlikely to have the opportunity for another dedicated lander search until later in the mission, maybe even next year,” adds ESA’s Rosetta mission manager Fred Jansen. “But the location of Philae is not required to be able to operate it, and neither does it need to be awake for us to find it.”

When will Philae wake up?

For those of you who followed the wake-up of Rosetta, you will know that it is not simply a case of switch on and get back to the science right away. The same goes for Philae.

Philae_orientation_visualisation_node_full_image_2[1]Philae orientation visualisation
The likely orientation of Rosetta’s lander, Philae, in a visualisation
of a topographic model of the comet’s surface.

At the original landing site, Philae was expected to receive around 6.5 hours of illumination per 12.4 hour comet day, with temperatures becoming too high by March 2015 to enable continued operations. Now, at its new location, the illumination is just 1.3 hours.

“Now we need the extra solar illumination provided by the comet’s closer proximity to the Sun by that time in order to bring the lander back to life,” says DLR’s Lander Project Manager Stephan Ulamec.

In fact, even by May, the Sun inclination will be such that it will be directly overhead of the predicted landing zone, although the lander’s orientation is such that it won’t be able to make full use of the maximum illumination on offer.

As for the process of wake up, and assuming Philae survived the low temperatures in its new residence, the earliest that the lander team expect it to be warm enough to boot up is in late March. But it will likely be May or June before there is enough solar illumination to use its transmitter, and to re-establish a communications link with Rosetta – the lander needs about 17 Watts to wake up and say “hello”.

Furthermore, the orbiter also has to be commanded to listen for Philae’s “I’m awake” signal, and be in a good position relative to the landing site to pick up the signal – although it can be up to 200 km away from the comet. It will be longer still before the battery is fully charged and Philae is ready to do science again, but that means there is a chance it will have a ringside seat for perihelion.

“We are already discussing and preparing which instruments should be operated for how long,” adds Stephan.

But even if Philae doesn’t wake up, it’s important to remember that it already completed its first science sequence on the comet, unexpectedly providing information from multiple locations on 67P/C-G.

Meanwhile Rosetta will continue to follow the comet on its orbit around the Sun and as it heads back towards the outer Solar System.

A great view of Curiosity’s travels in 28 months + Top space photos of the past month

NY Times offers a nicely made, elaborate graphics page illustrating the trek so far of the Curiosity rover, plus its activities along the way, since it landed in Gale Crater on August 5, 2012 : 28 Months on Mars –


Here’s a great collection of space photos just from the past month : Month in Space Pictures: Catch a Comet and a Cosmic Dawn – NBC

A lot is going on in space these days…

Student winners selected in “Future Engineers 3-D Printing in Space Tool Challenge”

An announcement on winners of the Future Engineers 3-D Printing in Space Tool Challenge:

Students Selected for Winning Designs of 3-D Printed Tools for Astronauts

After three months of designing and modeling, a panel of judges from NASA, the American Society of Mechanical Engineers Foundation (ASME) and Made In Space Inc. have selected the winners of the Future Engineers 3-D Printing in Space Tool Challenge.

The winner from the Teen Group (ages 13-19) is a Multipurpose Precision Maintenance Tool that Robert Hillan of Enterprise, Alabama, designed. The winner of the Junior Group (ages 5-12) is a Space Planter that Sydney Vernon from Bellevue, Washington, designed.


Teen Winner Multipurpose Precision Maintenance Tool
by Robert Hillan. Image Credit: Robert Hillan

The challenge asked students in grades K-12 to use their imagination to create and submit a digital 3-D model of a tool they think astronauts could use in space. “If an astronaut tool breaks, future space pioneers won’t be able to go to the local hardware store to purchase a replacement, but with 3-D printing they will be able to create their own replacement or even create tools we’ve never seen before.” said Niki Werkheiser, NASA’s In-Space Manufacturing Project Manager at the agency’s Marshall Space Flight Center.

This challenge tapped into the creativity and ingenuity of our nation’s future engineers to imagine interesting solutions to potential mission related problems. Models were received from 470 students across the United States.

Robert Hillan’s Multipurpose Precision Maintenance Tool has “a number of important tools which allow an astronaut to complete tasks with comfort and ease. The different sized drives at the top allows the user to attach sockets. In the center are wrenches of varying sizes, allowing fewer wrenches to be carried to the job site. On the left is a precision measuring tool along with wire gauges and a single edged wire stripper. In the center is an outline for Velcro to be applied allowing an easy storage around the station. A circular hole in the bottom center allows for a clip to be used as well. On the right, and ergonomic grip is built into the tool with ridges for better grasp, lastly a pry bar is built into the ergonomic grip for ease of access”. Robert will watch from NASA’s Payload Operations Center with the mission control team as their design is printed aboard the International Space Station.

3d-challenge-space-planter-vernon[1]Junior Winner Space Planter designed
by Sydney Vernon Image Credit:  Sydney Vernon

Sydney Vernon’s Space Planter model “would be used to grow plants on the ISS while being really water conservative. First, put the disc into the “mouth” of the creature. Tie a string to each of the ears and dangle them down through the hole in the disc into the lower part of the monster. Fill this lower part with water. Fill the top part with dirt and plant a seed. The plant will actually suck up any water it needs from the two strings dangling into the water, so it is very water-conservative. Also, it looks like a cute monster!”

Sydney Vernon of Bellevue, Washington during her finalist interview
with Astronaut Reid Weisman. Image Credit: Adrienne Gifford

Sydney‘s school will receive a 3-D printer. “First, I had a great time coming up with and designing my space tool. Then, I got told I would get a free 3-D print of what I’d made.  And today, I got to meet two NASA astronauts!!  This has been awesome!”

Winners were selected after a panel of expert judges interviewed the four highest rated winners from each age group. The panel members were Werkheiser, Mike Snyder, head of research and development, Made In Space Inc.; and NASA astronauts Reid Wiseman and Dr. Yvonne Cagle.

The top 10 entries from each age group are:

Teen Group (Ages13-19)

Junior Group (Ages 5-12)

  • Sydney Vernon, Bellevue, Washington – Space Planter  (winner)
  • Logan Castaldo, East Greenwich, Rhode Island – Rope of Usefulness  (semifinalist)
  • Aditya Hegde, San Diego, California – Sticky Grippers  (semifinalist)
  • John Humpherys, Treasure Island, Florida – Handy Helper  (semifinalist)
  • Maria Quinn, Whitefish Bay, Wisconsin – Cup Clamp  (semifinalist)
  • Trisha Sathish, Cupertino, California – Container O Storage  (semifinalist)
  • Nagasai Sreyash Sola, Ashburn, Virginia – Astro Multi-Tool  (semifinalist)

“The level of engagement during this challenge was amazing to observe.  I facilitated 70 future engineers in Coppell, Texas Kinder-5th grade.  After they watched the launch video they were ready to build what they knew about the challenge and what they needed to know. That became the living document that guided them to research and make decisions. Creating a 3-D tool was new to them. I have heard from other educators around the district, they are applying what they learned to other projects and using them in ways I would have never predicted. This was a real world challenge that allowed them to apply their creative skills in determining an innovative tool that would make life on the ISS easier or more fun.” said Jodi Schleter, Content Integration Coach, Coppell Independent School District.

The Space Tool Challenge is the first in series of Future Engineers 3-D Printing challenges for students focused on designing solutions to real-world space exploration problems. They are conducted by the ASME Foundation in collaboration with NASA and were announced in June as part of the White House Maker Faire to empower America’s students to invent the future by bringing their ideas to life. The next challenge will be announced in April 2015. For additional information on the Future Engineers 3-D Printing in Space Challenges or to sign up for information on upcoming challenges, visit the Future Engineers Website.

The challenge supports NASA Human Exploration and Operations Mission Directorate’s Advanced Exploration Division’s 3-D Printing in Zero-G ISS Technology Demonstration whose goal is to demonstrate the capability of utilizing a 3-D printer for in-space additive manufacturing technology. This is the first step toward realizing an additive manufacturing, print-on-demand “machine shop” for long-duration missions and sustaining human exploration of other planets, where there is extremely limited ability and availability of Earth-based logistics support. Advanced Exploration Systems pioneers new approaches for rapidly developing prototype systems, demonstrating key capabilities and validating operational concepts for future human missions beyond Earth orbit.

Citizen Science Milky Way Project finds new ‘Yellowballs” star formation features

NASA JPL highligs citizen science:

Citizen Scientists Lead Astronomers to
Mystery Objects in Space

Sometimes it takes a village to find new and unusual objects in space. Volunteers scanning tens of thousands of starry images from NASA’s Spitzer Space Telescope, using the Web-based Milky Way Project, recently stumbled upon a new class of curiosities that had gone largely unrecognized before: yellow balls. The rounded features are not actually yellow — they just appear that way in the infrared, color-assigned Spitzer images.

PIA18908_ip[1]Finding ‘Yellow Balls’ in our Milky Way galaxy

“The volunteers started chatting about the yellow balls they kept seeing in the images of our galaxy, and this brought the features to our attention,” said Grace Wolf-Chase of the Adler Planetarium in Chicago. A colorful, 122-foot (37-meter) Spitzer mosaic of the Milky Way hangs at the planetarium, showcasing our galaxy’s bubbling brew of stars. The yellow balls in this mosaic appear small but are actually several hundred to thousands of times the size of our solar system.

“With prompting by the volunteers, we analyzed the yellow balls and figured out that they are a new way to detect the early stages of massive star formation,” said Charles Kerton of Iowa State University, Ames. “The simple question of ‘Hmm, what’s that?’ led us to this discovery.” Kerton is lead author, and Wolf-Chase a co-author, of a new study on the findings in the Astrophysical Journal.

The Milky Way Project is one of many so-called citizen scientist projects making up the Zooniverse website, which relies on crowdsourcing to help process scientific data. So far, more than 70 scientific papers have resulted from volunteers using Zooniverse, four of which are tied to the Milky Way Project. In 2009, volunteers using a Zooniverse project called Galaxy Zoo began chatting about unusual objects they dubbed “green peas.” Their efforts led to the discovery of a class of compact galaxies that churned out extreme numbers of stars.

In the Milky Way Project, volunteers scan through images that Spitzer took of the thick plane of our galaxy, where newborn stars are igniting in swaths of dust. The infrared wavelengths detected by Spitzer have been assigned visible colors we can see with our eyes. In addition to the yellow balls, there are many green bubbles with red centers, populating a landscape of swirling gas and dust. These bubbles are the result of massive newborn stars blowing out cavities in their surroundings. The green bubble rims are made largely of organic molecules called polycyclic aromatic hydrocarbons (PAHs), cleared away by blasts of radiation and winds from the central star. Dust warmed by the star appears red in the center of the bubbles.

Volunteers have classified more than 5,000 of these green bubbles using the project’s Web-based tools. When they started reporting that they were finding more reoccurring features in the shape of yellow balls, the Spitzer researchers took note and even named the features accordingly. In astronomy and other digital imaging, yellow represents areas where green and red overlap. So what are these yellow balls?

A thorough analysis by the team led to the conclusion that the yellow balls precede the green bubble features, representing a phase of star formation that takes place before the bubbles form.

“The yellow balls are a missing link,” said Wolf-Chase, “between the very young embryonic stars buried in dark filaments and newborn stars blowing the bubbles.”

“If you wind the clock backwards from the bubbles, you get the yellow ball features,” said Kerton.

PIA18909_ip[1]Evolution of a massive star

The researchers explained why the yellow balls appear yellow: The PAHs, which appear green in the Spitzer images, haven’t been cleared away by the winds from massive stars yet, so the green overlaps with the warm dust, colored red, to make yellow. The yellow balls are compact because the harsh effects of the massive star have yet to fully expand into their surroundings.

So far, the volunteers have identified more than 900 of these compact yellow features. The next step for the researchers is to look at their distribution. Many appear to be lining the rims of the bubbles, a clue that perhaps the massive stars are triggering the birth of new stars as they blow the bubbles, a phenomenon known as triggered star formation. If the effect is real, the researchers should find that the yellow balls statistically appear more often with bubble walls.

“These results attest to the importance of citizen scientist programs,” said Wolf-Chase. Kerton added, “There is always the potential for serendipitous discovery that makes citizen science both exciting for the participants and useful to the professional astronomer.”

NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

For more information about Spitzer, visit: and