Missing comet lander Philae spotted at last: ESA (Update 2)

September 5, 2016
Rosetta's lander Philae has been identified in OSIRIS narrow-angle camera images taken on 2 September 2016 from a distance of 2.7 km. The image scale is about 5 cm/pixel. Philae's 1 m-wide body and two of its three legs can be seen extended from the body. The images also provide proof of Philae's orientation. A Rosetta Navigation Camera image taken on 16 April 2015 is shown at top right for context, with the approximate location of Philae on the small lobe of Comet Churyumov-Gerasimenko marked. Credit: Main image and lander inset: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; context: ESA/Rosetta/ NavCam – CC BY-SA IGO 3.0

Europe's Rosetta spacecraft has finally spotted its tiny lander Philae, thought to be lost forever, stuck in a ditch on the surface of a comet hurtling through space, ground controllers said Monday.

"THE SEARCH IS OVER! I've found @Philae2014!!" the European Space Agency (ESA) tweeted on behalf of Rosetta, orbiting comet 67P/Churyumov-Gerasimenko at some 682 million kilometres (424 million miles) from Earth.

The agency released a photo of the washing machine-sized robot lab on the comet's rough surface, one of its three legs thrust dramatically into the air.

This was the first sighting of Philae since its rough landing in November 2014.

The image was captured by Rosetta's OSIRIS narrow-angle camera on Friday and downloaded two days later—just weeks before the official end of the ground-breaking science mission to unravel the mysteries of life on Earth.

"With only a month left of the Rosetta mission, we are so happy to have finally imaged Philae and to see it in such amazing detail," Cecilia Tubiana of the OSIRIS camera team, the first person to see the images, said in a statement.

The Twitter page of Philae, its communications unit switched off in July, remained silent.

The 100-kilogramme (220-pound) probe touched down on comet 67P in November 2014, after a 10-year, 6.5 billion kilometre (four billion-mile) journey piggybacking on Rosetta.

Close-up of the Philae lander, imaged by Rosetta's OSIRIS narrow-angle camera on 2 September 2016 from a distance of 2.7 km. The image scale is about 5 cm/pixel. Philae's 1 m-wide body and two of its three legs can be seen extended from the body. The images also provide proof of Philae's orientation. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Philae bounced several times after its harpoons failed to fire, and ended up in a ditch shadowed from the Sun's battery-replenishing rays.

Until now, nobody knew exactly where.

The final hour

The tiny lab managed to conduct 60 hours of experiments and send home data before running out of power and entering standby mode on November 15, 2014.

"We were beginning to think that Philae would remain lost forever. It is incredible that we have captured this at the final hour," said Rosetta mission manager Patrick Martin.

The photo was taken at a distance of 2.7 kilometres from the surface of the comet, which is speeding away from the Sun at nearly 15 kilometres per second.

Rosetta is drawing closer to the comet for its own swansong.

An OSIRIS narrow-angle camera image taken on 2 September 2016 from a distance of 2.7 km in which Philae was definitively identified. The image has been processed to adjust the dynamic range in order to see Philae while maintaining the details of the comet's surface. Philae is located at the far right of the image, just above centre. The image scale is about 5 cm/pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

On September 30, Rosetta will crashland and join Philae on the surface—their eternal resting place.

After it touches down, communications with the craft will be severed once and for all, closing the historic mission.

The 1.3-billion-euro ($1.4-billion) project was conceived to unravel the secrets of comets—believed to be time capsules from the birth of the Solar System.

The comet-sniffing and -prodding exploits of Rosetta and Philae were closely followed around the world via cartoon recreations of the pioneering pair.

Philae, in particular, earned a loyal Twitter following.

In June 2015, as it drew closer to the Sun, some 30,000 people retweeted Philae's unexpected reawakening: "Hello Earth! Can you hear me?"

After eight intermittent communications with ground control, Philae fell forever silent in July 2015.

A number of Philae's features can be made out in this image taken by Rosetta's OSIRIS narrow-angle camera image on 2 September 2016. The images were taken from a distance of 2.7 km, and have a scale of about 5 cm/pixel. Philae's 1 m wide body and two of its three legs can be seen extended from the body. Several of the lander's instruments are also identified, including one of the CIVA panoramic imaging cameras, the SD2 drill and SESAME-DIM (Surface Electric Sounding and Acoustic Monitoring Experiment Dust Impact Monitor). Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

"Philae is at the foot of a cliff in an extremely rocky zone" of the comet, Rosetta project chief Philippe Gaudon of France's CNES space agency told AFP, after examining the picture.

It is now clear that after bouncing, Philae landed the wrong-way up, "with one foot well in the air and its antennas pointing... groundwards," he said.

That is why communicating with Philae had been so difficult.

"This wonderful news means that we now have the missing 'ground-truth' information needed to put Philae's three days of science into proper context, now that we know where that ground actually is," said Rosetta project scientist Matt Taylor.

Explore further: Video: Rosetta's second year at Comet 67P/Churyumov-Gerasimenko

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18 comments

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Milou
5 / 5 (3) Sep 05, 2016
A washing machine found 4 billion miles away in space. AMAZING!!!
RNP
4.5 / 5 (8) Sep 05, 2016
Agreed. And the images are absolutely amazing!
xstos
1 / 5 (4) Sep 05, 2016
Shouldn't it have been designed to be self-righting? Seems like having a teetering tripod landing on such rough terrain to be a shoddy design decision. Why not a spherical shape like a tumble weed so its orientation doesn't matter...
JB85
1 / 5 (5) Sep 05, 2016
Next time. Please. Install a beacon light on both the lander and spacecraft. The beacon would be similar to a camera flash. It could have a known frequency and flash at a known interval. It could even be used as another method of transmitting a coded message for lander or spacecraft status in case of emergency. Maybe for a planetary lander even install a beacon on the ejected shroud so it could be tracked during re-entry. Shroud entry aerodynamics could be useful data on high altitude atmospheric conditions of a planet.
Spacecraft designers now know better and should not repeat this fiasco.
Also the lander landed in a shadow and the camera was blind. Another flash light to illuminate the scene would be nice. Other spacecraft have had antenna fail to unfurl and scientists had to scratch their heads to figure out why. A simple camera looking at the spacecraft might save a salvageable mission.
physman
5 / 5 (9) Sep 05, 2016
@JB85 I feel like you are underestimating the sheer time and dedication that the experts have put into these projects. Undoubtedly they have thought about all these problems (and more) and come up with the optimal design in terms of cost and usefulness. Isn't your idea basically what they were already doing? But instead of using a camera and visible light they were using an antenna and presumably micro/radiowaves to send a signal (as with most communication)? The thing was, they weren't counting on the lander ending upside down due to those failed harpoons, how would a beacon have fared any differently if stuck in a crack upside down?

@xstos The same goes for you comment too I guess. How much would the self-righting system have weighed? How would the sphere even work? It certainly wouldn't be a very compact design IMO. Getting it to science good is one problem, getting it to space in the first place is another. Both of these issues need to be weighed up during design simulatenously
Dragnet
5 / 5 (4) Sep 05, 2016
Every additional feature adds weight and complexity. Easy to second guess the tough decisions and trade-offs the experts at ESA had to make in order to put Rosetta and Philae on target. Not so easy to do a better job of it. With only a few short weeks left before Rosetta's mission ends on the comet's surface with Philae, what I'd really like to see ESA's engineers and scientists do is attempt a close rendezvous with Philae! Maybe it's too late. Is Rosetta's remaining propellant sufficient and its reaction motors capable of such fine navigation? Navigation under robotic control? If so, could Rosetta's batteries even sustain it during the hazardous dip into shadow? Would it then still be capable of communicating with Earth? If the answer is yes to these and other important questions, why not give it a go? While the spacecraft may be incapable of conducting further meaningful science, what an amazing feat of robotic programming and engineering such a rendezvous would be!
xstos
1 / 5 (6) Sep 05, 2016
I was just trolling. It's funny how seriously people take comments on here lol.
Charlie_G
3 / 5 (2) Sep 05, 2016
"one of its three legs thrust dramatically into the air"

Had a little chuckle at that line...
physman
not rated yet Sep 05, 2016
@xstos lol jkz
JB85
1 / 5 (2) Sep 06, 2016
@physman
I am aware of the complexity of space flight, which is why I said "next time".
Missions now being planned and built should have simple location devices in addition to mission systems.
Cost, weight and power are very low for a (strobe or flash) light, even less for a corner reflector.
Mission teams have done amazing things to save or extend missions by creative use of every resource. Two to six devices should cover a typical spacecraft configuration.

Thorium Boy
1 / 5 (8) Sep 06, 2016
340M miles away and it was using solar panels instead of an RTG or more compact nuclear source for power. Big mistake. NASA is being run into the group by proggy environmentalists more interested in bolstering the man-made global warming theory than space exploration.
antialias_physorg
5 / 5 (9) Sep 06, 2016
340M miles away and it was using solar panels instead of an RTG or more compact nuclear source for power. Big mistake. NASA is being run into the group by proggy environmentalists more interested in bolstering the man-made global warming theory than space exploration.

Yay...another knee-jerk post by a complete idiot.
(Hint: This is an ESA mission, not a NASA mission)
jonesdave
5 / 5 (8) Sep 06, 2016
Let's not forget that the lander completed its nominal mission. Anything else would have been a bonus. Had the harpoons worked, I'm sure there would have been more. Unfortunately, a report advising that the explosives used in that system may degrade over time, came a little too late to do anything about it - the craft had already launched! Yes, they have learned something for next time.
Dragnet
3.7 / 5 (3) Sep 06, 2016
@jonesdave & physman -- well said.
Sonhouse
1 / 5 (1) Sep 06, 2016
I'm wondering if they could manouver the orbiter to nudge the lander on the way down to get it back to the sun. I guess the question would be moot if the lander had to be intermediary to communicate with Earth. If the lander is totally independent communications wise it might work if it could nudge it just a little on the way down.

Be a bit tricky manouver though, just a bit:)
BrettC
1 / 5 (4) Sep 06, 2016
Maybe Rosetta could reflect light onto Philae to get it running again.
Sonhouse
5 / 5 (1) Sep 06, 2016
The image is showing a sliver of light hitting the lander. Too bad it is in a crevase like it is.

Rosetta would have to have a big reflector to do that though and it would have to be continuously adjustable to keep light on Philae. Just a case of bad luck where it landed. Gravity is so slight there you could kick one of those big rocks into orbit if you were yourself tied down...
antialias_physorg
5 / 5 (2) Sep 07, 2016
I'm wondering if they could manouver the orbiter to nudge the lander on the way down

No. It's in a crevasse. Rosetta is circling already very close (at 2.7km out) given the peculiar geometry of the comet. any closer would be extremely dangerous.

Maybe Rosetta could reflect light onto Philae to get it running again.
Rosetta isn't stationary. If it were it would eventually crash. Even if it were stationary it has no highly reflective and plane surfaces. Even if it did there's no guarantee that the reflected spectrum would match the spectrum needed for the solar panels to work. Even if it did: Philae's panels are pointing in the wrong direction. So: No.

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