GRACE Follow On

The Power Supply for theGravity Recovery And Climate Experiment Follow On Mission

APCON delivered flight models to customer. The integration on system level is under progress now.

Gravity Recovery And Climate Experiment Follow On Mission (GRACE-FO)

The Laser Ranging Interferometer (LRI) is based on a laser interferometer evaluating the heterodyne signal of two single infrared frequency lasers (?=1064,547 ± 0.057 nm(in vacuum)) with a frequency offset in the MHz range.
The optical system on both spacecraft is identical. It consists of a laser, a triple mirror assembly (TMA) and an optical bench subsystem (OBS).
The OBS consists of the optical bench assembly (OBA) and the external optical bench electronics (OBE) box.

APCON has developed and produced the power supply and mirror drive unit for the Optical Bench Electronics, Laser Ranging Instrument.


The Power supply is based on a discrete design.

- Input filter and Input Current Limiter with latch
- Input Voltage Limiter (Transient protection)
- Primary Under-Over-Voltage Protection
- PWM Pre-Regulator and Push/Pull Power stage
including transformer
- Rectifier and output filter and Secondary Series
- ACM Buck (average current mode)Converter
- Monitoring (Power Fail circuits secondary Voltages)
- Monitoring (Output Coil Current Measurement by
an OP-Amplifier)

Secondary voltage regulators, 14 Outputs
± Voltage Analog Front End
± PID-Control (OP-Amplifier)
± Voltage PID/SM-Power Stage
± Voltage PSS (Position Sensing System)
± Voltage Analog Backend

Secondary regulation galvanically isolated (transformer-coupled)

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