LDPE (Long Duration Propulsive EELV Secondary Payload Adapter (ESPA)) are experimental satellites built for the U.S. Air Force Space and Missiles Center (AFSMC) to carry small payloads and deploy small satellites.
Orbital ATK, now Northrop Grumman, had been awarded a contract in December from the U.S. Air Force Space and Missiles Center (AFSMC) to build LDPE space platforms. The innovative platform, positioned between the launch booster and a primary space vehicle, is used to carry small payloads or deploy small satellites. Under the contract, Orbital ATK will design and manufacture the LDPE using its ESPAStar platform. The award includes the initial LDPE, plus options for two additional systems.
ESPAStar uses a modified EELV Secondary Payload Adapter ring as its structure and is capable of being launched aboard any launch vehicle that meets the EELV standard interface specification. It provides a modular, cost effective and highly capable platform for hosting technology development and operational payloads. ESPAStar leverages work performed on the company-designed EAGLE (ESPA Augmented Geostationary Laboratory Experiment), which successfully demonstrated similar technology for the U.S. Air Force. In addition to EAGLE, two ESPAStars are currently in production for other customers.
ESPAStar provides power, pointing, telemetry, command and control for attached payloads or for small satellites that can be deployed from the vehicle. Built to provide an even greater level of access to space, Orbital ATK's ESPAStar can accommodate any combination of up to six hosted or 12 separable, free-flyer payloads in low and geosynchronous orbit.
The LPDE program has been renamed ROOSTER (Rapid On-Orbit Space Technology and Evaluation Ring), but the first three missions are still refered to by the name LDPE.
LDPE 1 flew on the STP-3 mission on an Atlas-5(551)² together with the STPSat 6 main payload. The mission carries four experiments, which could be either hosted or deployable. The experiments have not yet been disclosed. At least one satellite, Ascent, was deployed from LDPE 1.
LDPE 2 flew on the USSF-44 mission on a Falcon-Heavy (Block 5)(px). The hosted payloads include: Mustang, a small size/weight/power communications experiment; Xenon, a commercial off-the-shelf component maturation for flight at GEO; and Energetic Charged Particle-Lite, an SSC space weather sensor. Three free-flying payloads are to be deployed from LDPE 2: Alpine, a Millennium Space Systems program to demonstrate GEO small satellite designs and leverage commercial GEO communications; LINUS, a Lockheed Martin Independent Research and Development GEO servicing risk reduction effort; and Tetra 1, an SSC prototype small satellite designed as a pathfinder for streamlined acquisition processes, innovative methods of space vehicle design and on-orbit Tactics Techniques and Procedures development.
LDPE 3A flew on the USSF-67 mission also on a Falcon-Heavy (Block 5)(px). It hosts five payloads, which remain attached. Two demonstration prototype payloads from Space Systems Command are on board. The Aerospace Corporation is responsible for one of them, Catcher, which is a prototype sensor designed to provide local space domain awareness insights. It is based on an earlier Aerospace Corporation-developed instrument known as Energetic Charged Particle-Lite (ECP-Lite), and is designed to demonstrate new miniaturized technology capable of diagnosing the adverse effects of radiation, charged particles, and other space weather events on spacecraft in orbit. WASSAT is the other Space Systems Command payload. It is a prototype wide-area sensor with four cameras that searches for and tracks other spacecraft and space debris in geosynchronous orbit, where communications, missile detection, intelligence-gathering, and weather monitoring satellites operate. LDPE 3A carries three payloads from the military's Space Rapid Capabilities Office, including two operational prototypes for space situational awareness missions and one operational prototype crypto/interface encryption payload providing secure space-to-ground communications capability. There are no free-flying payloads on this mission.
The fourth mission, ROOSTER 4 is planned to fly in 2026.
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