(Analyzer of Space Plasma and Energetic Atoms)


ASPERA-3 is designed to study the solar wind-atmosphere interaction in the near-Mars space through ENA (energetic neutral atom) imaging and in-situ plasma measurements.


The device itself is comprised of four sensors:

Neutral Particle Imager (NPI)

The NPI sensor surveys the ENA fluxes with a high angular resolution while the NPD sensor performs the velocity and mass measurements.

Neutral Particle Detector (NPD)

The NPD sensor extends the ENA images in two new dimensions, mass and energy. The energy spectra produced by this sensor supplies direct information about the temperature and plasma bulk velocity in the interaction region and the magnetospere.

By remotely measuring the energy of the accelerated planetary ions and global configuration of the escaping plasma, the NPD and NPI sensors allow a determination of the total ion outflow which is the crucial parameter in the understanding of the atmospheric erosion process under the solar wind action.

Electron Spectrometer

The Electron Spectrometer is a variation of the spherical tophat electrostatic analyzer (Sablik et al, IEEE Trans. on Geosciences & Remote Sensing, Vol 28, No. 6, 1990, pp 1034 – 1048). The variation is the flattening of the first 17° of the inner spherical electrode and a corresponding flattening of the spherical cap to plate. Sablik et al 1990 optimized the spacings to achieve best focus. The end result is to improve the energy resolution by ~3.5 for a fixed set of plate radii without a large loss of geometric factor. No other variation of parameters for a pure spherical system can achieve this goal.

In addition, extensive effort has been taken to ensure a solar rejection of >10-13. This is accomplished by the inclusion of a light trap in the outer plate and a new form of copper black on all surfaces exposed to solar UV. Ray tracing indicates these techniques will meet this goal.

Mass: 304 gm

Power: 584 mW (including high voltage supplies and front end electronics)

Dimension: 112 x 41 mm

Raw TM rate: 8192 bps

Energy Range: 1 eV to 20 keV (128 steps)

Energy Level: Click here

Energy Resolution ΔE/E: 8%

Acceptance Angle: 360° x ±2°

Geometric Factor (22.5°): 5.77 x 10-4 cm2 sr

Geometric Factor x ΔE/E(22.5°): 4.75 x 10-5 cm2 sr eV/eV

Ion Mass Analyzer (IMA)

The IMA is a mass resolving spectrograph that provides measurements of the main ion components (H, H2, He, and O). The mass detection technique utilized by IMA is ideal for the detection of ions of all masses, including sub-micron sized “dusty” plasma components.

Both the Ion Mass Analyzer (IMA) anode and Electron Spectrometer (ELS) are funded by NASA as a Discovery Program Mission of Opportunity.