WASHINGTON NASAs plans to drive its selections of science and research satellites into the commercial world has reshaped the nature of its relationships with the U.S. commercial launch industry, a senior NASA official tells space.com. "Its in the world of ELVs (Expendable Launch Vehicles) where weve been able to bring faster, better, cheaper to fruition," according to Karen Poniatowski of NASA Headquarters Office of Space Flight. "What you see are design cycles on the spacecraft going from selection to flight in roughly three years."

Previously that same period would have taken from five to in some cases eight or nine years. By using commercial spacecraft buses and other "off-the-shelf" technologies in the design of the satellites, she said that NASA was able to refocus its "constrained budgets" on the scientific instruments that the probes would carry into space.

Those smaller, commercial-sized spacecraft have triggered a boom in civil space launch opportunities. "What it translates, though is that when we look at our mission model, a few years ago we were doing four or five ELV launches a year," she explained. Today, as a result of the shift towards smaller and commercial, that number is "going on an average of eight to 10."

Those reduced-size missions call mainly for Delta II and Pegasus launch vehicles. The Deltas NASA has been ordering, under a blanket launch services agreement structure, have been "Med-lite" Delta rockets using reduced numbers of strap-on booster motors than those used on the more powerful Delta II variants. "These are lower performance (vehicles) and thus have lower cost," Poniatowski said.

The agency has been turning to the Pegasus XL winged launcher, carried aloft by a Lockheed L-1011 carrier plane and air launched into space, when missions need a "lower inclination" orbit or a unique type of orbit inclination. "Pegasus isnt bound by the same range constraints" as those launchers that fly from fixed launch pads, which limit the inclination (angle that the rocket can fly). Because Pegasus is launched from an airplane, that plane can offer any trajectory that a customer might need.

As far as larger boosters, the space agency has but five flight reservations aboard Atlas-class carriers still on their manifest. The payloads include the GOES satellite, TERRA, and the Tracking Data and Relay Satellite System (TDRSS). The follow-on Atlas purchases have been for additional TDRSS and GOES missions. TRDSS used to be orbited aboard the NASA space shuttles, but were moved to expendable launchers to save cost and preserve the shuttle for unique missions that needed a human astronaut crew present.

Poniatowski said the shift towards smaller satellites is reshaping NASAs capabilities in science missions. "Payloads are shrinking," she said. "When we first looked at how to bring the cost down, using more off-the-shelf technology, we found we could give the scientists more frequent flight opportunities." She also said that by relying more on commercial satellite designs, the agency was seeking to streamline the costs of doing its procurements. "Were trying to reduce the number of unique buses built in-house," Poniatowski said. "Our focus now is on instrument development."

As NASA selects science missions, NASAs Office of Space Flight advises the experimenters what class launch vehicles are available for their specific mission design. The cost of each project selected in the Explorer and Discovery programs includes representative costs of the rocket type needed to launch the mission. The actual contracts for the launch service comes from either pre-existing blanket agreements for launch services with several providers or a specific contract announcement for the launch needed. The launch service provider, and not NASA, actually chooses the launch site.

The one area that NASA felt was being inadequately served by industry was in upper stages, that part of a launch vehicle that sends the satellite to its final destination. "Upper Stages are a gap," she said. NASA headquarters and the Marshall Spaceflight Center in Huntsville, Alabama were working together with industry to lay out new design possibilities and the types of new stages that might be needed for commercial launchers and for flight aboard the space shuttles for future deployable payloads.

"Were going to rely on the commitment of the commercial world to build the new generation of launch systems," Poniatowski predicted. NASA planning documents currently show five small-class launches, two Med-lite launches, and five medium-class launches (Titan II or full size Delta IIs) in calendar year 2000. For calendar year 2001, planning documents show three small-class launches, three Med-lite launches, three medium-class launches, and two intermediate-class (Atlas II or Delta III) launches.