Rosetta in Valentine's space flirt with comet

Think of it as the equivalent of an interstellar tango dance. On February 14 -Valentine's Day - a European spacecraft swoops within just a few kilometers of the comet we've been trying to observe closely since last August.

The European Space Agency's (ESA) Rosetta spacecraft altered its orbit to get up close and personal with the 67P/Churyumov-Gerasimenko comet, on which it dropped the Philae lander all those months ago.

Since then scientists have been trying to locate the lander, which failed to attach itself to the comet as planned.

The flyby at a distance of just six kilometers is the closest any spacecraft has ever been to a comet and in cosmic terms.

But besides the romance, there is a scientific reason for the rendezvous.

ESA scientists want to get near enough to measure gases and dust that only hang out near the comet's surface.

"There might be gasses and rare particles that are too heavy to go far away from the comet," Rosetta mission flight director, Andrea Accomazzo, told DW. "The cameras in particular will get a higher resolution and this is why they want to see it up close."

Rosetta has already been beaming back some amazingly detailed photos of the comet, including images of jets of particles spewing from its surface.

ESA scientists expect a new round of high-resolution pictures to arrive within a week.

They also hope to examine the surface of the comet to search for clues as to how the comet was formed.

Much of it is covered by a layer of dust, which has made it difficult for scientists to search for ice patches and other details from Rosetta's earlier orbit about 26 kilometers away.

"We are hoping to see water and ice and we don't see ice patches on the surface yet," says Accomazzo. "They are all covered by a layer of dust. Once they see these things they can speculate more about the comet itself, how it formed and how it changed over time."

Romeo and Juliet

There is another romantic angle to Rosetta's Valentine's Day flyby, but this time it's a little more Romeo and Juliette.

Last November, Rosetta launched a small probe to the surface of the comet. But the spacecraft, named Philae, landed with a series of bumps and ended up in a shadowy area of the comet.

Philae's batteries ran out of power and the probe has been out of contact ever since. Scientists still don't know exactly where Philae is.

Rosetta could theoretically search for her lost companion but the spacecraft will pass by the comet on the wrong side. Accomazzo says searching for Rosetta's "Romeo," while potentially romantic, would be a waste of time.

"Technically it would be absolutely possible to design a mission so that we could find [Philae]. But to do that we would have to compromise the rest of the mission, all the scientific aspects," says Accomazzo. "If we go with closer orbits maybe in June or July we might have the chance - more than 50 percent."

Rosetta and Philae could still be reunited later this year as comet 67P travels close enough to the sun to recharge Philae's batteries.

Until then we will be left only with their last known "communication," a series of tweets sent between the spacecraft and the lander before Philae lost contact.

Whether or not Rosetta and Philae rekindle their romance, ESA scientists are still excited for what's to come with the Rosetta mission. The spacecraft will continue to dance with comet 67P, making passes at the comet from varying distances as it accompanies it on its trip around the sun later this year.

Scientists will continue to learn from the pictures and measurements from Rosetta until the mission terminates at the end of 2015.