A Look at the Payloads in Falcon Heavy’s STP-2 Mission
HAWTHORNE, Calif. (SpaceX PR) — The Department of Defense (DoD) Space Test Program-2 (STP-2) mission, managed by the U.S. Air Force Space and Missile Systems Center (SMC), is targeting launch on June 24, 2019, with the launch window opening at 11:30 p.m. ET. Lifting off from Launch Complex 39A at the Kennedy Space Center in Florida, this mission will deliver 24 satellites to space on the DoD’s first ever SpaceX Falcon Heavy launch vehicle.
The STP-2 mission will be among the most challenging launches in SpaceX history with four separate upper-stage engine burns, three separate deployment orbits, a final propulsive passivation maneuver and a total mission duration of over six hours. In addition, the U.S. Air Force plans to reuse side boosters from the Arabsat-6A Falcon Heavy launch, recovered after a return to launch site landing, making it the first reused Falcon Heavy ever flown for the U.S. Air Force.
The Mission
The STP-2 multi-manifest (rideshare) launch will demonstrate the capabilities of the SpaceX Falcon Heavy launch vehicle and provide critical data supporting certification for future National Security Space Launch (NSSL) missions. In addition, SMC will use this mission as a pathfinder for the development of mission assurance policies and procedures related to the reuse of launch vehicle boosters.
The STP-2 payloads are assembled from a host of mission partners including the National Oceanic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA), DoD research laboratories, and university research projects. STP-2 provides a unique space access opportunity for DoD and inter-agency science and technology missions that directly enhance the space capabilities of the U.S. and its allies and partners.
Payloads
Demonstration and Science Experiments
The Air Force Research Laboratory’s Space Vehicle Directorate’s Demonstration and Science Experiments (DSX) spacecraft will conduct basic research on the harsh radiation environment of medium-Earth orbit (MEO). DSX will perform three primary experiments:
- The Wave Particle Interaction Experiment (WPIx) will resolve critical feasibility issues for very-low frequency (VLF) wave-particle interaction.
- The Space Weather Experiments (SWx) will measure and map the distributions of energetic protons, electrons and low-energy plasma in the inner magnetosphere to improve environment models for spacecraft design and operations.
- The Space Environment Effects (SFx) will determine the MEO environmental effects on common electrical components, circuits and materials. This includes NASA’s Space Environment Testbeds (SET) experiments. SET will characterize how radiation driven by the Sun impacts hardware over time, paving the way for mitigating the effects of solar activity on spacecraft design and operations.
COSMIC-2
COSMIC-2 is a partnership between NOAA, the U.S. Air Force (USAF), NASA’s Jet Propulsion Lab (JPL), Taiwan’s National Space Organization (NSPO), the UK’s Surrey Satellite Technology Limited (SSTL), the Brazil Institute of Space Research (INPE), and the Australia Bureau of Meteorology (BoM). This six-satellite constellation will provide next-generation Global Navigational Satellite System Radio Occultation (GNSS-RO) data. Radio Occultation data is collected by measuring the changes in a radio signal as it is refracted in the atmosphere, allowing temperature and moisture to be determined.
- International collaboration between Taiwan (NSPO) and the United States (NOAA)
- Collects atmospheric data for weather prediction and for ionosphere, climate, and gravity research
Green Propulsion Infusion Mission

A Ball Aerospace engineer adjusts the thermal insulation on NASA’s Green Propellant Infusion Mission spacecraft bus following integration of the propulsion system. (Credit: Ball Aerospace)
The Green Propellant Infusion Mission, or GPIM, is a NASA mission that develops a “green” alternative to conventional spacecraft propulsion systems. With the green propellant, launch vehicle and spacecraft fuel loading will be safer, faster, and much less costly. The “shirt sleeve” operational environment GPIM offers will reduce ground processing time from weeks to days.
- Demonstrates a new form of safe propulsion
- Improves propulsive efficiency while reducing handling concerns
Learn more about Ball Aerospace, Aerojet Rocketdyne and NASA’s Green Propellant Infusion Mission.
Oculus
Oculus-ASR was developed by students at the Michigan Technological University in Houghton, MI through the Air Force Research Laboratory’s University Nanosatellite Program to provide calibration opportunities for ground-based observers attempting to determine spacecraft attitude and configuration using unresolved optical imagery.
- Features spectrally distinct surfaces and shape profiles that can be observed from Earth’s surface
- Records attitude time history for error correction in ground-based observations
Orbital Test Bed
General Atomics Electromagnetic Systems’ Orbital Test Bed (OTB) is a versatile, modular platform based on a flight-proven “hosting” model to test and qualify technologies. On STP-2, OTB hosts several payloads for technology demonstration, including the Deep Space Atomic Clock designed, built and operated by NASA’s Jet Propulsion Laboratory on behalf of the Space Technology Mission Directorate to revolutionize how spacecraft navigate.
- Flexible technology demonstration platform
- Hosts a miniaturized, high-stability atomic clock that will gain or lose less than a second of error in 3 million years
Learn more about General Atomics Electromagnetic Systems and NASA’s Deep Space Atomic Clock.
NPSat hosts two experiments built by the Naval Research Laboratory (NRL) to investigate space weather and support space situational awareness (SSA), including ionospheric electron density structures that cause radio scintillations impacting communications and navigation.
- Monitors electron content and scintillations using radio frequency (RF) transmissions
- Conducts Coherent Electromagnetic Radio Tomography (CERTO) experiment
- NRL-built Langmuir probe takes in-situ measurements to improve ionospheric modeling
Prox-1
Prox-1 is a microsat developed by students at the Georgia Institute of Technology in Atlanta through the Air Force’s University Nanosat Program to demonstrate satellite close proximity operations and rendezvous.
- Demonstrates small satellite close-encounter operations
- Prox-1 deploys the LightSail-B CubeSat developed by the Planetary Society
CubeSats
E-TBEx: Measures distortion of radio signals traveling through the ionosphere using beacon tones transmitted from eight orbital locations: the six COSMIC-2 satellites and the twin E-TBEx CubeSats
Launch Environment Observer (LEO) & StangSat: Measures thermal and vibration environments during launch and demonstrates Wi-Fi data transmission between Cubesats (2 separate cubesats)
PSAT: Supports global amateur radio data relay capabilities to assist students and researchers around the world
TEPCE: Demonstrates the feasibility of using electrodynamic propulsion by deploying a 1 km electrically conductive tether, performing orbit-changing maneuvers without consuming any fuel
LightSail-B:The Planetary Society’s citizen-funded solar-sailing spacecraft propelled by the Sun
One response to “A Look at the Payloads in Falcon Heavy’s STP-2 Mission”
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LightSail-B Let’s hope Falcon Heavy is a better ride than some old Soviet SLBM. Good luck guys.