AFRL's Demonstration and Science Experiments (DSX) mission

Abstract

The Air Force Research Laboratory, Space Vehicles Directorate (AFRL/RV) has developed the Demonstration and Science Experiments (DSX) mission to research technologies needed to significantly advance Department of Defense (DoD) capabilities to operate spacecraft in the harsh radiation environment of Medium-Earth Orbits (MEO). The ability to operate effectively in the MEO environment significantly increases the DoD's capability to field space systems that provide persistent global space surveillance and reconnaissance, high-speed satellite-based communication, lower-cost GPS navigation, and protection from space weather and environmental effects on a responsive satellite platform. The three DSX physics-based research/experiment areas are:1. Wave Particle Interaction Experiment (WPIx): Researching the physics of Very-Low-Frequency (VLF) electromagnetic wave transmissions through the ionosphere and in the magnetosphere and characterizing the feasibility of natural and man-made VLF waves to reduce and precipitate space radiation;2. Space Weather Experiment (SWx): Characterizing, mapping, and modeling the space radiation environment in MEO, an orbital regime attractive for future DoD, Civil, and Commercial missions; and 3. Space Environmental Effects (SFx): Researching and characterizing the MEO space weather effects on spacecraft electronics and materials.Collectively, thirteen individual payloads are combined together from these three research areas and integrated onto a single platform (DSX) which provides a low-cost opportunity for AFRL due to their common requirements. All three experiments require a 3-axis stabilized spacecraft bus (but no propulsion), a suite of radiation sensors, and extended duration in a low inclination, elliptical, MEO orbit. DSX will be launch-ready in summer 2010 for a likely launch comanifest with an operational DoD satellite on an Evolved Expendable Launch Vehicle (EELV).Keywords: Wave Particle Interaction, electromagnetic wave transmissions, space radiation, characterization of MEO MISSION OBJECTIVESThe top-level objectives for the DSX space flight experiment are to investigate the electromagnetic wave-particle (electron, proton, ion) interaction in the MEO region of space between the Van Allen radiation belts, also known as the 'slot' region; to collect space weather data in the slot region; and to collect data on the degradation of microelectronics, thermal, optical, and mechanical structures, surfaces, and coatings in the slot region. DSX is planned for an objective mission life of one year 1 due to the amount of data expected to be collected and required to meet program objectives, and due to normal operating procedures at the Space and Missile Systems Center (SMC) Research, Development, Test, and Evaluation (RDT&E) Support Complex (RSC) at Kirtland Air Force Base (KAFB) for flying experimental satellite missions.The overall primary objective of DSX is to resolve critical feasibility issues of injecting VLF waves into the magnetosphere to determine how efficiently, how effe...

Whistler waves with angular momentum in space and laboratory plasmas and their counterparts in free space

“…Active wave injections from ground transmitters produced a wealth of nonlinear phenomena, among them involving whistler modes [22][23][24]. Active wave injections from spacecraft are still in its beginnings [25]. Few electric dipole and magnetic loop antennas have been deployed successfully including long tethers [26].…”

“…Whistler modes can be excited by electric or magnetic antennas inside or adjacent to plasmas. In space plasmas electric dipoles are preferred [25] since large magnetic loops have been difficult to deploy [125]. In laboratory plasmas it is generally known that helicon waves are best excited with magnetic antennas rather than electric dipoles.…”

Space access for small satellites on rideshare missions with ESPA and ESPA-derived payload adapters

“…The spacecraft is currently being integrated and a launch co-manifest with an operational DoD satellite is planned. [7] ESPA Grande strength margins were predicted using finite element analysis with four 660-lb (300-kg) APLs on the ports and a 15,000-lb (6803-kg) primary spacecraft. The model included interface adapters above and below the Ring to simulate realistic launch stack adjacent structures.…”

“…DSX on orbit configuration with ESPA as hub of spacecraft[7] 3. ESPA GRANDE ESPA Grande has a larger spacecraft capacity compared to ESPA.…”

Controlled precipitation of energetic Van Allen belt protons by electromagnetic ion cyclotron (EMIC) waves

“…Initially, research efforts on remediation were directed at the trapped energetic electrons [Imhof et al, 1983;Inan et al, 1984Inan et al, , 2003Kulkarni et al, 2008], since they are the preponderant product of High-Altitude Nuclear Explosions (HANEs) [Brown and Gabbe, 1963;Mozer et al, 1963;Pieper, 1963]. The possible utilization of man-made whistler waves for this purpose has been studied extensively, and a space test of a linear antenna is expected to launch in 2016 [Spanjers et al, 2006;Scherbarth et al, 2009]. Both energetic electrons and protons, however, represent a great hazard to spacecraft.…”