Air Force’s STP-S26 Mission Loaded with New Technologies

WASHINGTON — The U.S. Air Force’s experimental STP-S26 mission is slated to launch Nov. 19 in an effort to demonstrate a myriad of new space technologies, including a command and control system, atmospheric sensors, and satellite deployment and propulsion systems.

The mission will be the 26th launched by the Air Force’s Space Test Program, which coordinates launches for experimental payloads from across the U.S. government. Seven satellites encompassing 16 experiments are now fully integrated and encapsulated atop a Minotaur 4 launch vehicle counting down the final days until launch from Kodiak Launch Complex in Alaska, said Air Force Lt. Col. Tim Cole, the mission’s launch vehicle program manager.

Four of the satellites are in the 180-kilogram class, about the size of small refrigerators, and three are cubesats weighing just a couple of kilograms each.

The Minotaur 4 launch vehicle, built by Orbital Sciences Corp. of Dulles, Va., is based on three repurposed U.S. Peacekeeper ICBM solid rocket motors and a fourth stage powered by Alliant Techsystems’ Orion 38 solid rocket motor. The rocket made its suborbital debut in April, followed by its first orbital mission in September.

The third Minotaur 4 flight will mark a number of firsts for the rocket, Cole said in a Nov. 9 media briefing. This will be the first Minotaur 4 launch from Alaska, and it will be the first to use a new multi-payload adapter plate, upon which the four larger satellites are mounted.

The STP-S26 mission also will be the first Minotaur 4 vehicle to deploy payloads into two different orbits. The rocket’s four conventional stages will carry it to a 72 degree inclined orbit 650 kilometers above the Earth, where all seven satellites will be deployed. Then its Hydrazine Auxiliary Propulsion System will propel a dummy payload to an altitude of about 1,100 kilometers, where a new Boeing-developed payload separation system will deploy the ballast, Cole said.

The primary payload for the STP-S26 mission is the STPSat-2 spacecraft, built for the Air Force by Ball Aerospace & Technologies Corp. of Boulder, Colo. STPSat-2 uses the first production version of the Space Test Program-Standard Interface Vehicle, a 110-kilogram satellite platform designed to host the majority of the experiments considered for launch by the Space Test Program, said Ken Reese, the Air Force’s STPSat-2 program manager.

“The [Standard Interface Vehicle] is ideal for science and technology development missions,” Reese said. “We can accommodate up to four independent payloads and launch on a variety of launch vehicles.”

The satellite will carry two payloads: the Ocean Data Telemetry Microsat Link, which will relay data from ocean and terrestrial sensors, and the Space Phenomenology Experiment, which will evaluate sensor compatibility in the space environment, Reese said.

STPSat-2 will be the first satellite operated by a new command and control system called the Multi-Mission Space Operations Center at Schriever Air Force Base, Colo. The ground system is designed to fly multiple constellations of spacecraft with various missions.

Also on board the STP-S26 mission is the first Fast, Affordable Science and Technology Satellite — or FASTSat — built by 13 Huntsville, Ala.-based organizations, including Dynetics Corp., the Von Braun Center for Science and Innovation, Marshall Space Flight Center and the University of Alabama. The satellite was designed and built in less than 15 months and hosts six atmospheric experiments, said FASTSat mission manager Mark Boudreaux.

FASTSat is unique because it will be the first free-flying satellite to deploy a separate free-flying cubesat, Boudreaux said. Once on orbit, FASTSat will eject NASA’s Nanosail D experiment, which aims to be the first satellite to deploy a solar sail for propulsion in low Earth orbit. Developed by Marshall and NASA Ames Research Center in Mountain View, Calif., the 10-centimeter cube will unfurl a bed sheet-sized sail about as thin as a tissue that will propel the satellite as it catches photons from the sun. Nanosail D will use its solar sail to deorbit itself, potentially demonstrating a new way to bring satellites and debris back to Earth without any chemical propellant, Boudreaux said.

The other two larger satellites on the STP-S26 mission are the University of Texas’s Formation Autonomy Spacecraft with Thrust, Relnav, Attitude and Crosslink satellite and the U.S. Air Force Academy’s FalconSat-5 spacecraft.

The mission’s two other small satellites, which measure about 30 centimeters by 10 centimeters, are NASA’s Organism/Organic Exposure to Orbital Stresses craft and the National Science Foundation’s Radio Aurora Explorer craft.