posted 10-05-2025 07:13 AM               

Space Cover 826: Clementine

Back in Space Cover of the Week 732, Ray talked about the 1998-99 Lunar Prospector mission and how it verified the Clementine probe's 1994 finding of water on the moon. So, what was Clementine? Let's try to fill that gap.

Above is a cover postmarked at NASA Goddard on January 25, 1994, for the launch of Clementine (also known as the Deep Space Program Science Experiment). Goddard-managed tracking stations provided communications and tracking for Clementine while in Earth orbit, and two Goddard scientists served as advisors on Clementine's science investigations.

The Clementine moon probe was a joint effort between the Department of Defense (Ballistic Missile Defense Organization - BMDO) and NASA. The primary objective of the mission was to test new equipment that BMDO hoped to use in detecting hostile missiles launched against the United States. It just so happened that the radiation environment in deep space provided a more stringent test environment than Earth orbit, and the sensors being tested could do some great scientific investigation of the Moon, hence NASA being involved.

Launched from Vandenberg AFB onboard an excessed Titan II ICBM, Clementine reached lunar orbit on February 19, 1994, the first probe to the Moon in over 20 years. Clementine produced the first complete map of the Moon including the Moon's poles (prior efforts to map the Moon concentrated on Apollo landing sites that were closer to the Moon's equator). In addition to photo coverage, detailed elevations of lunar surface features were measured for the first time.

And as noted before, some innovative use of the radar on Clementine indicated that water may have been present in the permanently shaded portions of a lunar polar crater. And water was the "Holy Grail" that would drive future lunar exploration (Think about why today's lunar return efforts are focusing on the South Pole of the Moon – water!). So, Clementine was a fundamental precursor to today's push to return to the Moon!

And Clementine did all of that in just over two months of orbiting the Moon! On May 3, 1994, Clementine's engine was fired to propel it out of lunar orbit and toward Asteroid 1620 Geographos to do even more science. Unfortunately, an anomaly occurred several days later that ended the mission before it could reach the asteroid.

Today, the engineering model of Clementine resides at the Smithsonian National Air and Space Museum, reflecting the major contribution of Clementine to lunar exploration.

You are probably wondering why I've highlighted a cover postmarked at NASA Goddard, who had limited involvement in Clementine, as a Space Cover of the Week. And not a cover postmarked at the Vandenberg AFB launch site; or near the Clementine mission control center in a warehouse in Alexandria, VA; or a Deep Space Network site that provided communications and tracking at lunar distances. Good question! And the answer is simple – this is the only Clementine cover that I have been able to find! Clementine was a pretty low-key project back in the mid-'90's and didn't seem to attract the attention of many cover servicers back then. Do any of you have other Clementine covers? Please post 'em!!!

posted 10-05-2025 06:18 PM               

The first cover at top is indeed for the actual launch day on Feb. 25, 1994, with a postal hand strike at the Vandenberg Air Force Branch at Lompoc, CA.

The second at left, with a purple and orange printed cachet, was on Feb. 19, 1994 that same year, as Dennis has, with a nice hand cancel from Greenbelt, MD, home of NASA's Clementine tracking support center. On this day the Titan IIG-launched Clementine spacecraft began lunar orbital operations.

Yet, there is another cover though, posted at Greenbelt that same year on May 3, when Clementine left moon orbit. I think these are the only three SVC issues for the not-too-well-known lunar probe. To the best of my knowledge, I do not known of any other space cover collectors nor dealers that were able to acquire launch day cancels except Robert Rank. It wasn't a classified launch, if I recall, so why was it missed by so many others?

posted 10-18-2025 03:57 PM               

This cover was signed by Pete L. Rustan, who was the Mission Manager for Clementine, when he was visiting Onizuka Air Force Station in Sunnyvale, CA.