A flock of small satellites for a diverse group of international organizations was lost Wednesday after a converted rocket from Russia's strategic missile arsenal fell back to Earth moments after launch.

The three-stage, 111-foot tall Dnepr rocket fired out of an underground missile silo at 1943 GMT (3:43 p.m. EDT), or in the late-night hours at complex 109 at the Baikonur Cosmodrome in the arid grasslands of Kazakhstan. The Dnepr is a decommissioned R-36M ballistic missile - also called the SS-18 Satan in Western circles.

Information suggests something went wrong early in the launch sequence. Various Russian news reports say the rocket's first stage engine was switched off 86 seconds after liftoff. This was about ten seconds before the powerplant was to have shut down before giving way to the Dnepr's second stage.

The booster and its paying cargo crashed some 16 miles south of the launch pad, but no damage or injuries have been reported, according to the Interfax news agency. An investigation into the accident is underway, and recovery forces are being dispatched to the debris area.

A four-chamber RD-264 engine powers the Dnepr's first stage, which is unmodified from the version used by the R-36M missile.

"The State Launch Committee continues their work to investigate what happened," a senior Kosmotras manager told payload officials. "We have some preliminary information of the cause (of the failure). They have an idea of what might have happened. They know the location of where the rocket fell. They are performing the debris recovery plan."

"All we can say right now is that it's a pity, and we're really sorry."

The launch had been postponed from last month due to problems found while preparing the Dnepr rocket. Officials opted for a one-month delay to replace the booster with a back-up before proceeding with launch operations, news reports said last month.

The Dnepr carried 18 satellites in all, including a remote sensing spacecraft for Belarus, a Russian student-built satellite, two Italian university microsatellites, and 14 palm-sized CubeSat payloads housed inside five portable deployment devices.

The destination for the launch was a Sun-synchronous orbit about 325 miles high with an inclination of 97.4 degrees.

The largest payload lost in the launch accident was BelKA - the first orbiting satellite for Belarus. The Earth observation platform was built by Energia in Russia to carry out a robust remote sensing campaign for Belarus and other users worldwide. Major objectives of the five-year mission included mapping, climate observations, and tracking geological processes.

BelKA's manufacturer says the satellite was designed to capture both visible and infrared images in high resolution. These pictures were then to have been digitally sent to communications stations scattered across Russia. Plans then called for the images to be sold commercially. The project cost approximately 230 million rubles, which converts to around $9 million, media reports said.

A Russian microsatellite built by a group of students at the Moscow State Technical University was also aboard the doomed rocket launch. Called Baumanets, the small spacecraft was to have operated in space for at least one year as an educational tool and technology pathfinder for students.

The Dnepr rocket also carried two Italian student payloads. UniSat 4 was the fourth member of a series of microsatellites managed by professors and students at the University of Rome. Another - called PICPOT - was designed and developed by engineering students in Torino, Italy.

Fourteen tiny CubeSat spacecraft mounted atop the failed launcher were to been deployed from five carriers shortly after reaching orbit. Students at universities around the world provided most of the four-inch wide, two-pound craft. Contributors for this launch included teams from the Universities of Arizona, Illinois, Kansas, Hawaii, Montana State University, Cal Poly, Hankuk Aviation University in Korea, Nihon University in Japan, the Norwegian University of Science and Technology, and The Aerospace Corporation.

The CubeSat program - developed and run by officials at Cal Poly and Stanford University - offers opportunities for colleges and other low-budget groups to build miniature spacecraft for roughly $40,000. Customers then deliver their completed CubeSat satellites to integration teams at Cal Poly, who load them into their protective launch containers before shipping the payloads to the launch site. The project currently consists of over 40 universities, high schools, and private companies, according to its web site.

The next CubeSat launch was scheduled for this fall using another Dnepr rocket to deliver seven of the diminutive satellites into orbit.

Six previous space launches of the Dnepr all ended in success, most recently two weeks ago when the Genesis 1 inflatable space habitat was hauled into orbit for U.S.-based Bigelow Aerospace. A total of 23 spacecraft have also been successfully released into orbit since commercial launches began in 1999.

Another Dnepr rocket was slated to launch a follow-on Genesis module by the end of this year. However, the schedule for future flights of the Dnepr will likely remain in flux until an investigation determines the cause of Wednesday's failure and any necessary fixes.

The Dnepr launcher is marketed by ISC Kosmotras, an international company formed in 1997 by Russia and Ukraine.