Philae Struggles To Stay In Contact With Earth

In this self-portrait by Philae using its panoramic cameras to photograph its location on the side of a cliff on Comet 67P/Churyumov-Gerasimenko. Credit: ESA
In this semi self-portrait taken by Philae with its panoramic cameras, we see two of the lander legs and the side of the cliff it’s hung up on. Credit: ESA

Stubborn Philae. Engineers with the Rosetta mission have repeatedly tried to get in touch with the little lander on the surface of the Comet 67P/Churyumov-Gerasimenko but to no avail. Three weeks after Philae surprised everyone by contacting Earth, there’s still no steady link that would allow mission control to talk to the lander and tell it to fire up science operations again.

Most frustrating, the lander’s batteries are fully charged and the probe’s all toasty, warmed up by the increasing amount of sunlight that’s been falling across its landing site this summer. Philae has attempted to make contact with Rosetta at least 7 times between June 13 and 24, but the signal is either extremely brief or it breaks up the way a radio station does in your car when you drive out of range.

Using a model of the comet, Dr. Koen Geurts shows where Philae is located and uses a piece of rolled up paper to show the shape and direction of Philae's "communication cone". For Rosetta to contact or hear Philae, it must fly over the top of the cone. Credit: ESA
Using a model of the comet, Dr. Koen Geurts shows where Philae is located and uses a piece of rolled up paper to show the shape and direction of Philae’s “communication cone”. For Rosetta to contact or hear Philae, it’s orbit must take it over the top of the cone. Credit: ESA

If a solid connection could be established, the Philae team could respond and then upload commands to restart the science mission. Today, Dr. Koen Geurts and the lander team will try for a second time to make contact using the CONSERT instrument, a type of sounding device on Philae that measures the structure and composition of the comet’s deep interior via the two-way communication between spacecraft and lander.

Location of the planned landing site on the comet and where it's located now after it bounced several times before finally landing last fall. Credit: ESA
Location of the planned landing site on the comet and where it’s located now after it bounced several times before finally landing last fall. Credit: ESA

Rosetta sent an instruction to Philae’s instrument, which has its own antenna separate from its normal communications antennae, telling it to restart. We won’t know until tomorrow if the lander responded. If and when it does and science stars anew, one of the first things mission control will ask it to do is take fresh photos of its surroundings. Drop by tomorrow and maybe I’ll have some good news.

UPDATE July 10: And I do have good news! Geurts and team learned their attempt to activate Philae’s CONSERT connection last week worked. Yesterday afternoon, for 12 stable minutes, Philae transmitted measurement data from the instrument to Rosetta which relayed the information to Earth. After that the connection failed again. Still.

“This sign of life from Philae proves to us that at least one of the lander’s communication units remains operational and receives our commands,” said Geurts.