The European Space Agency have had some nervous hours due to unexpected movement by the Philae spacecraft that landed on Comet 67P/C-G yesterday.

In fact, after it initially touched the comet, Philae's stabilizing harpoons did not fire and the lander "lifted off." It was in and out of communication for about two hours as it made a long, slow-motion bounce toward a rocky cliff on the comet surface. It landed, but then bounced again, with communication loss of about 7 minutes. After that, scientists received steady data. The lander's scientific instruments - which activated at Philae's first touch - have been collecting information on the comet.

There is loss of telemetry as Philae's mothership (the comet-orbiting Rosetta) moves over the horizon, but engineers have determined the lander is on the side of a rocky cliff (see photo) and is not securely attached to the comet.

A major problem is Philae is mostly in shadow and not able to get a full charge from its solar panels. The on-board batteries can only last so long without another charge.

To sum up, the lander's instruments are working perfectly, but it is not getting much solar charge and it appears to be only tenuously attached to the comet.

The main spacecraft, Rosetta, is in good shape and, no matter what happens to Philae, will be accompanying the comet as it passes by the Sun and moves back out into the solar system. That will be an amazing journey.

Already, scientists are thrilled with what the craft has discovered about what comprises a comet. Get ready to revise those textbooks.

You can get all science "geeky" by watching the videos at the ESA website. You'll get used to the accents.