Possibly stupid question: why are all the images greyscale? Could we not send a color camera? Or is the comet very grey? Or does color not work in space?
The comet is in fact very very black, but pretty much all cameras are greyscale. Most 'colour' cameras are just a series of filters placed over the pixels to sense only light of the desired colour (usually RGB)
When science has to be done, it's easier to have a selectable set of filters you can put in front of the whole sensor at once. This way you can use the full sensor resolution and you can have a wider variety of filters. They also tend to bring along spectrometers of some description which are again much much more useful.
I know that sometimes, images are first sent in black and white to save on data, color is sent later.
Hubble apparently only does black and white. color images can be obtained using a technique involving two of its black and white images. But that is a telescope, probably not similar.
Also, cameras are much more sensitive and higher resolution if they are B&W. A colour camera has to have a bayer matrix filter in front of the pixels (or some other weird trick) which throws away a load of the light.
Generally, when telescopes want colour images, they will take several pictures with different filters in front of the telescope, then combine them. This is useful because you can have a wide selection of filters, including ones for specific science-related wavelengths, like hydrogen alpha, or oxygen emissions. A normal colour camera is limited to three filters.
