Last week, ATK (News - Alert) announced the end of the Tactical Satellite-3 (TacSat-3) mission. On April 30, 2012, the satellite burned up in the Earth's atmosphere after nearly three years of service from its May 2009 launch. But it's a happy, abet fiery, ending.

Built for the U.S. Air Force and designed as a faster-cheaper alternative to more expensive satellite platforms, TacSat-3 was designed as an experimental platform to have six months of operation with a goal of one year.   It instead beat all of its mission requirements and goals and was transitioned to operational service in 2010.

TacSat-3 demonstrated the capability to conduct hyperspectral imaging to support the needs of U.S. war fighters. Its primary instrument was the Raytheon (News - Alert) ARTEMIS (Advanced Responsive Tactically Effective Military Imaging Spetrometer) sensor, capturing light across many different wavelengths to detect such things as areas of disturbed earth and to see "through" foliage and camouflage to better track enemy movement.

Designed and built in fewer than 15 months as a rapid development project for the U.S. Air Force's Operationally Responsive Space (ORS) office, the U.S. Air Force Research Laboratory (News - Alert) demonstrated the usefulness of the sensor and platform during the first year of operation by providing downloadable information directly to troops within 10 minutes of sending a tasking order as it flew overhead -- that's collection, on-board processing without the need of a third-party ground station or hardware, and downloading the image during a single 10 minute pass.

The Air Force Space Command assumed control of the ARTEMIS sensor in May 2010 and retained it through February 2012, when the satellite was removed from operational status and transferred to the Space and Missile Systems Center in February 2012 for more experimentation during the rest of its on-orbit life.

Given the number of different U.S. Air Force organizations that used TacSat-3 during its lifetime, it's a fair statement that the taxpayers got their money's worth for an "experimental" platform.  Air Force Space Command reports the satellite got a retirement ceremony with full military honors on April 13, describing it as a "true American success story, a classic underdog and overachiever, inspiring those lucky enough to develop and operate it."

TacSat-3's list of accomplishments include the ability to providing intelligence for the wartime missions of all geographic combatant commands as well as humanitarian efforts, such as Operation Tomadachi during the nuclear emergency in Japan and the Gulf oil spill cleanup in the United States -- the latter efforts relatively unheard of.

Built and launched at a price of around $88 million, according to Air Force Space Command, TacSat-3 featured ATK's small spacecraft common bus, a standardized hardware interface to plug in different payloads.   TacSat-3 acted as a pathfinder for future flexible, modular bus satellites, including the ORS-1 imaging satellite launched in July 2011.

It is likely TacSat-3's instruments and mission could have kept going for much longer, but the satellite was built without attitude thrusters to keep costs down. What ultimately brought the satellite down wasn't a hardware failure, but the earth's gravity.