ELFIN’s populated Instrument Data Processing Unit for the spacecrafts Development Model

ELFIN’s primary payload consists of a fluxgate magnetometer and two energetic particle detectors. These instruments are being developed in-house by UCLA staff members in the Earth, Planetary and Space Sciences department. For more information about ELFIN’s scientific mission, please visit the science page.


ELFIN will also be flying a Switching Instrument Power Supply (SIPS) and an Instrument Data Processing Unit (IDPU) which support the primary instruments in their operation. ELFIN students are extensively involved in the design and layout for these instrument boards.


The Fine Sun Sensor on a mobile stand conducting tests outside in the sun

The Fine Sun Sensor on a mobile stand conducting tests outside in the sun

ELFIN students are also responsible for designing and testing systems to protect the scientific instruments. As ELFIN spins at 20 revolutions per minute, the particle detectors may frequently be exposed to direct sunlight. The electron particle detector is largely shielded from the resulting influx of photons by a covering over the aperture, but the ion particle detector is more exposed. Direct exposure of the particle detectors to sunlight while the instruments are taking measurements can temporarily desensitize the detectors.

The current focus of the payload subsystem is refining aperture designs and testing flight and ground software for the spacecraft’s Fine Sun Sensor. The Fine Sun Sensor, with a field of view greater than those of the particle detectors, is designed to protect the particle detectors from exposure to direct sunlight. As ELFIN’s particle detectors rotate into sunlight, the Fine Sun Sensor can be used to alert the detectors to temporarily shut off and restart only once the detectors have rotated out of direct exposure.

Data from the Fine Sun Sensor can also be used to determine the spacecraft’s attitude. By precisely determining the position of the sun when the sun is within the sensor’s field of view, the Fine Sun Sensor can validate ADCS sensors.