Some busy days are coming up for the American space program. One spacecraft will fly past the planet Mercury, and another will fly past a watery moon of the planet Saturn. And if everything's on schedule, astronauts will pay a final call on Hubble Space Telescope.
Step one comes early Monday morning, when a craft called Messenger scans Mercury. This is actually its second visit to Mercury. The first came in January. Its eventual goal is to enter orbit around the planet. But it needs to use Mercury's gravity to slow it down, and to line up the right trajectory.
Messenger is only the second craft to study Mercury. The first saw just half of the planet, so Messenger is offering the first look at the other side. When it's done, it should provide detailed maps of the entire planet.
Next up, on Thursday, is Cassini, which will fly just a few dozen miles from Enceladus, a small moon of Saturn. During earlier passes, Cassini discovered that liquid water squirts into space from around the moon's south pole. This time, Cassini will provide a close look at that region of Enceladus, allowing scientists to map where the water's coming from.
And as early as next week, space shuttle Atlantis will carry astronauts to Hubble for one last upgrade. The crew will repair some ailing systems, and add new instruments. This final visit should keep the telescope going for several more years -- providing plenty of busy days for space scientists.
Script by Damond Benningfield, Copyright 2008
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