The Demonstration and Science Experiments (DSX) Mission

Wm. Robert Johnston1, James McCollough1, Michael Starks1, and Jay Albert11Air Force Research Laboratory, Space Vehicles Directorate, Kirtland AFB, NM

Abstract: In 2016, the Air Force Research Laboratory will launch its Demonstration and Science Experiments mission to investigate wave-particle interactions and the particle and space environment in medium Earth orbit (MEO). The DSX spacecraft includes three experiment packages. The Wave Particle Interaction Experiment (WPIx) will perform active and passive investigations involving VLF waves and their interaction with plasma and energetic electrons in MEO. The Space Weather Experiment (SWx) includes five particle instruments to survey the MEO electron and proton environment. The Space Environmental Effects Experiment (SFx) will investigate effects of the MEO environment on electronics and materials. We will describe the capabilities of the DSX science payloads, science plans, and opportunities for collaborative studies such as conjunction observations and far-field measurements.

Distribution A. Approved for public release; distribution unlimited. OPS-15-9274

• Low Energy ElectroStaticAnalyzer (LEESA): AFRL/RVB• 5 angular zones, total FOV

120° x 12°; 30 eV – 50 keV e-, ions

• Compact Environmental Anomaly Sensor (CEASE): AFRL/RVB• telescope: FOV 60°; dosimeters:

FOV 90°; 100 keV – 6.5 MeV e-; 20 – 100 MeV p+

• Low-energy Imaging Particle Spectrometer (LIPS): PSI, AFRL• 8 angular zones, FOV 79° x 8°; 30 keV – 2 MeV e-, p+

• High-energy Imaging Particle Spectrometer (HIPS): PSI, AFRL• 8 angular zones, FOV 90° x 12.5°; 1 – 10 MeV e-, 30 – 300 MeV p+

• High Energy Proton Spectrometer (HEPS): ATC, Amptek, AFRL• 1 look direction, FOV 24° (p+), 40° (e-); 20 – 440 MeV p+

Fig. 2

Summary• DSX will be a unique mission, studying active VLF transmission

interactions with the MEO plasma and particle environments.• It will also study the ambient particle and wave environments,

including opportunistic conjunction experiments with ground transmitters and with other satellites.

• DSX supports diverse opportunities for collaborative studies.• DSX mission particle data is already cleared for release to

collaborators; similar approval for wave data is expected.

SWx: Space Weather ExperimentWPIx: Wave Particle Interaction Experiment

DSX Mission• Launch: September 2016• Orbit: MEO (medium Earth

orbit), 6000 x 12000 km, 42° inclination, 5.3 hr period

• Orbit in slot region• Nominal duration: 1 year

DSX Spacecraft

SFx: Space Environmental Effects Experiment• Transmitter (TNT): UMass Lowell, SWRI, Lockheed-Martin

• 3 – 50 kHz at up to 5 kV (9 kV at end of life)• 50 – 750 kHz at 1W (local electron density)

• Receiver (BBR/SRx): Stanford, Lockheed-Martin, NASA/Goddard• 3 B components (TASC), 2 E components (dipole antennas)• Frequency range: 100 Hz – 50 kHz

• Vector Magnetometer (VMAG): UCLA, UMich• 0 – 8 Hz three-axis measurement, ±0.1 nT accuracy

• Loss Cone Imager (LCI): Boston University, AFRL• High Sensitivity Telescope (HST): FOV 6.5° centered on loss cone; 100

– 500 keV e-• Fixed Sensor Heads (FSH): 3 angular zones, 180° x10°; 50 – 700 keV e-

• DSX primary mission: study VLF transmission, propagation, and interaction with trapped particles

• Space Environment Testbed (SET): NASA/JPL• Quantify effects of the MEO environment on new technologies• CREDANCE (Cosmic Ray Environment Dosimetry And

Charging Experiment), ESA particle sensor and dosimeter• DIME-1 and -2 dosimeters (Clemson Univ.)• ELDRS (AZ State) proton effects on bipolar junction transistors• COTS-2 (CNES/NASA)

• COTS (Commercial off-the-shelf) Radiometers and Photometers: AFRL/RQ• Determine basic physics of material breakdown and effects on

material properties applicable to thin-film photovoltaics

• Validation of attitude control technologies targeting flexible structural modes: AFRL

• WPIx will also observe the ambient wave environment, including intervals dedicated to lightning, transmitters

• Will investigate basic physics of an antenna in a plasma which are not well understood [Wang and Bell, 1972, JGR, 77:1174; Song et al., 2007, JGR, 112: A03205]

• Far field effects soon become complex (see figure at right)

• DSX secondary mission: map electron and proton particle populations in MEO

• SWx will also study dynamics of the particle population in the slot region (see figure at right)

• LEESA will support WPIx by diagnosing the plasma environment during experiments

• Conjunction opportunities with:• Van Allen Probes• VLF and Particle Mapper (VPM)—LEO (low

Earth orbit) 6U nanosatellite with VLF receiver and electron spectrometer (AFRL)

• CASSIOPE (CAScade, Smallsat and Ionospheric Polar Explorer)—LEO

• TARANIS (Tool for the Analysis of Radia-tions from lightNings and Sprites)—LEO

Payload Module (PM)• VLF Broad Band Receiver• VLF Narrow Band Receiver• VLF Transmitter/Amplifier Tuners• Loss Cone Imager (LCI)• Space Weather Instruments:

LEESA, CEASE, LIPS, HIPS• Radiometers• Photometers

Z Axis Booms• VLF Electric Field Rx• DC Magnetometer

Y Axis Booms• VLF Electric Field Rx/Tx

Tri-axial Search Coil (TASC)• VLF Electric Field Rx

ESPA Ring• Primary

Structure• Interfaces

between EELV and Primary Satellite

Avionics Module (AM)• Space Weather Instrument (HEPS)• Attitude Control System• Bus Computer• Experiment Computer• Thermal Control• Communications• Power

ACE: Adaptive Control Experiment