BackForwardInstrument:  TWINS 

Instrument details
Acronym TWINS
Full name Two Wide-angle Imaging Neutral-atom Spectrometers
Purpose To provide stereoscopic imaging of the magnetosphere for improved understanding of its structure and processes
Short description Simultaneous Energetic Neutral Atom (ENA) images from two widely separated locations are taken to implement stereoscopy. The instrumentation consists of a neutral atom imager covering the 1-100 keV energy range with 1 min time resolution
Background Coupled to a simple Lyman-alpha imager to monitor the geocoronal hydrogen density to aid in ENA analysis while environmental sensors provide contemporaneous measurements of the local charged particle environments.
Scanning Technique Measurements taken across the Magnetosphere as the satellites move along the highly elliptical orbit (Molniya). Field of view about 2.5 sr centered approximately about nadir from each of 2 spacecrafts
Resolution 4º x 4º for H atoms with energies > 10 keV
Coverage / Cycle Full magnetosphere volume
Mass 18.7 kg Power 25.3 W Data Rate 50 kbps


Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2006 to 2020
Last update: 2022-07-25
Detailed characteristics
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Solar and space environment monitors
  • Energetic particle spectrometer
WIGOS Subcomponents
  • Subcomponent 2
  • Magnetospheric energetic particles and magnetometers
  • Geomagnetic field sensor [in LEO and cross magnetosphere]
Mission objectives
Primary mission objectives
  • Energetic Neutral Atom (ENA)
Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Energetic Neutral Atom (ENA)*1 - primaryNo specific limitation.Interplanetary space, medium energy (over 1000 up to 100000 eV)