article_snippet.sent: The spacecraft is expected to smash into the closest planet's surface at 2.4 miles per second
article_snippet.sent: The event will take place on Thursday 30 April at 3:30pm Eastern Time (7.30pm GMT).
article_snippet.sent: However, when The event does, Messenger will be behind Mercury, and hidden from Earth. '
article_snippet.sent: The last couple of hours will probably be pretty quiet,' Mercury mission head Sean Solomon told Nature. '
article_snippet.sent: There will be a final orbit when The spacecraft passes behind the closest planet and we won't hear from The spacecraft again. '
article_snippet.sent: The spacecraft is expected to smash into the planet's surface on Thursday 30 April after a four-year mission .
article_snippet.sent: It is due to impact on the surface at the end of April as the planet's gravity slowly pulls the planet's gravity down out of the planet's gravity current orbit .