Tropical storm delays Mercury mission
Take-off put back 24 hours
The launch of the Mercury Messenger probe, the first mission to study Mercury in more than 30 years, has been put back by 24 hours, mission controllers said today. The spacecraft was due to launch from Florida’s Kennedy Space Centre at 6:16 this morning, but the launch was scrubbed when Tropical Storm Alex got a little close for comfort.
A statement on the Messenger mission website said that at present, the forecast for tomorrow’s launch time is similar to today’s weather. “However, if Tropical Storm Alex moves farther away, the forecast would likely improve,” it says.
Alex is the first named storm of the year, was upgraded from a depression on Sunday, and is expected to make landfall within the next 24 hours. It is not expected to hit Florida, but hurricane warnings have been issued for the coasts of both North and South Carolina.
The Messenger mission gets its name from “MErcury Surface, Space ENvironment, Geochemistry, and Ranging,” - a list of its main mission objectives. Specifically, scientists hope to discover why the planet is so dense, and how its magnetic field is generated.
Mercury is the only planet, other than Earth, that has a global magnetic field. On Earth, scientists think the magnetic field is generated by our planet’s spinning molten iron core. However, Mercury is much smaller and its core should have frozen solid long ago. The question is: how can a solid iron core generate a global magnetic field? The answers could shed light on how our own field works. The 1.2 tonne spacecraft will escape our gravity well aboard at Boeing Delta 2 rocket. Its seven-year, 7.9bn km flight to Mercury will see it swing past Earth again in 2005 for a gravity boost, before heading towards the inner solar system. It will make two passes of Venus - in 2006 and 2007 - which will aim it closer to a Mercury Orbit.
The craft will be wrapped in heat resistant ceramic cloth, to help it withstand surface temperatures of up to 450C. It carries seven scientific instruments which it will use to probe the mysterious planet. The scientific payload includes stereo imaging equipment, a laser altimeter, a magnetometers, and an X-ray Spectrometer.
One of its primary tasks is to map the planet’s surface, completing a task begun by Mariner 10 in 1973: Mariner 10 was able to photograph just 45 per cent of the planet’s surface during three flybys.
Messenger also carries equipment capable of determining the composition of the atmosphere and surface, and the Radio Science package will detect variations in the thickness of the planet's crust.
Tomorrow's launch is set for 06:15, GMT. The mission has a 13-day launch window, so even if Tropical Storm Alex proves troublesome for a couple of days, the craft should still be able to get off the ground before the window expires. ®