Mars webcam goes dark

Stephen Withers
Tuesday, 09 December 2008 08:12

Science - Space

Mars has moved behind the Sun (from an Earthbound perspective), so the webcam aboard the Mars Express space probe has been shut down until the northern spring.

The problem is that the Sun's upper atmosphere adversely affects radio communications with the spacecraft, so it has been put into hibernation for a month to help ensure its survival.

And even when Mars Express comes out of hibernation, the distance between  the two planets is particularly large (370 million kilometres) which affects the speed at which data can be transmitted.

The 45,700bps connection speed is comparable with a dial-up Internet link - in other words: slow.

On top of that, instruments including the High Resolution Stereo Camera will be pumping out data at a remarkable rate - more than 3 gigabits on some days.

Do the arithmetic and you'll see there isn't much spare capacity on the link.

Accordingly, low priority activities including the Visual Monitoring Camera (VMC, aka the Mars webcam) will be suspended for a longer period.

The VMC is expected to resume operation in the early northern spring of 2009.