Two very different spacecraft with very different missions to very different places are currently completing a long journey.

For LCROSS, it will be the very end of the mission — the spacecraft, launched this summer in tandem with the LRO mission to the moon, is about to slam into one of the permanently shadowed craters of the moon’s South Pole called Cabeus-A. It will be a spectacular double impact: at 7:30 a.m. Milledgeville time Oct. 9, the Centaur upper stage of the original launch vehicle will smash into the surface, excavating a hole roughly 60 feet across and some 9 feet deep.

A debris plume will rise high above the surface of the moon, and on the West Coast astronomers with decent telescopes will be able to observe the event. Alas, here at home the sky will already be way too bright, but of course we’ll be able to see it all on the news or online. And that’s not all — the impact event will be directly observed by the actual LCROSS spacecraft, which will take pictures and take scientific measurements as it passes through the debris cloud. Four minutes later it will be Lights Out for the LCROSS spacecraft as well when it, too, crashes into the moon, observed by other telescopes all over the night side of the world.

Scientists hope to identify traces of water vapor in the impact plume. Water ice on the moon could be a tremendous asset and a huge money-saver for future lunar settlements as it would greatly reduce the amount of water that would have to be hauled up from Earth at exorbitant costs.

For the primary impactor, the Centaur Upper Stage, it will be a brief but glorious moment in the limelight. One of the unsung heroes of the space program, it tends to get a whole lot of hard work and no public recognition. For some 30 years the Centaur has sat atop an Atlas rocket and given many spacecraft the final boost for their fantastic journey. Mariner, Pioneer, Viking and Voyager all relied on the Centaur as the upper stage of their launch vehicle. Finally, after all these years and reliable service, a Centaur stage will be something other than space junk, and it will go out in style!

Hopefully in the next OUR SPACE column you will be able to read all about LCROSS and the Centaur going down in a blaze of glory. Keep your fingers crossed for a slam dunk, and drop a bookmark at www.nasa.gov/mission_pages/LCROSS/main/ for all the latest news on the upcoming impact event.

Meanwhile — today, as a matter of fact — the MESSENGER spacecraft will swing by the solar system’s innermost planet, Mercury, for the last time before heading out into deep space again, only to return in 2011 and finally go into orbit around the first rock from the sun. MESSENGER stands for MErcury Surface, Space ENvironment, GEochemistry, and Ranging (yep, one of those clever NASA acronyms).

It’s been a while since we checked in with our pal heading to Mercury, but since its launch Aug. 3, 2004, MESSENGER has performed flawlessly. It has passed by its intended goal twice on a far-flung slingshot maneuver that will allow it to be captured into an orbit around Mercury on its next approach. While its major mission will begin then it has already done yeoman’s work observing and mapping the planet, taking spectacular pictures of never before seen terrain and making all sorts of unexpected discoveries.

Getting to Mercury in this circuitous manner saved the spacecraft a lot of fuel and thus drove down the mission cost a great deal. Granted, it took it a very long time to get there, but there’s no rush to get there any faster. MESSENGER will be the first spacecraft ever to go into orbit around Mercury, and who know what it may discover on its extended stay with the mysterious planet.

Why Mercury? Since it is the closest planet to the sun, Mercury experiences some of the most extreme temperature fluctuations of any body in the solar system. Its surface is old and dates back to the very formation of the planets — without an atmosphere to cause erosion by wind or precipitation we are bound to be amazed at what we’ll find on this ancient surface.

Like the Earth, Mercury also possesses a global magnetic field, unlike Venus or Mars. And, perhaps most curiously, Mercury has some permanently shadowed craters around its poles, and there is evidence of highly reflective material discernible by radar wavelengths. Could it be water ice? Nobody knows. But the mere possibility makes MESSENGER a scientific sibling to the LRO/ LCROSS mission. Serendipity in action? Perhaps so. After all, both LCROSS and MESSENGER achieve a major milestone right around the same time. Keep up with MESSENGER at http://messenger.jhuapl.ed

u/index.php where a cool countdown feature gives you constant updates about mission elapsed time, upcoming events and constantly changing awesome images.

Beate Czogalla is the associate professor of theater design in the Department of Music and Theater at Georgia College & State University. She has had a lifelong interest in space exploration and has been a solar system ambassador for the Jet Propulsion Laboratory/ NASA for many years. She can be reached at our_space2@yahoo.com