MESSENGER's Big Day...

At 5:45 pm PST today, MESSENGER will start its 15 minute long orbital insertion burn.  With any luck at all, after over 6 years of incredibly complex travel, MESSENGER will be safely parked in a highly elliptical orbit around the planet Mercury – the first explorer from earth to have done so.  The last time any explorer visited Mercury was on March 16, 1975 – almost exactly 36 years ago – when Mariner 10 made its third and final high-speed fly-by.

I remember Mariner 10 quite well, as I thought its pioneering use of the “gravitational slingshot” technique was both clever and fascinating.  MESSENGER is itself a rather extreme example of that same technique in action; without it, MESSENGER's fuel budget would have been prohibitively large.

The scientists and engineers of the MESSENGER project must be very excited right about now.  They've been waiting for this moment since MESSENGER's launch on August 3, 2004, some six and a half years ago.

Fare thee well, MESSENGER!