Sony is currently testing its Spresense board to see if it can withstand the harsh environment of space, and if successful, it could head to the moon’s surface inside a transformable robot.
The Spresense is a compact board based on a six-core Arm Cortex-M4F with 1.5 Mb of SRAM and 8 Mb of Flash. It features GPIO, I2S, SPI, I2C and UART like many other microcontrollers on the market. It also packs GNSS and a dedicated parallel interface for camera support. What’s more, it consumes very little power, making it an attractive option for space applications that rely on solar power for operation.
JAXA (Japan Aerospace Exploration Agency) invited Sony to participate in a program to design hardware for upcoming space missions, and Spresense was their submission. One of the goals will include a demonstration of the microcontroller in a low Earth orbit satellite mission. Testing whether the board can handle a space environment includes vibration and shock, which verifies it can withstand a rocket launch into orbit. To do this, the microcontroller is subjected to low and high-frequency tests and shock tests at different frequencies. The high-frequency tests involved a range of frequencies from 10 to 2kHz in a power spectrum density range of 0.1 to 2.0G2/Hz, with forces equivalent to between 82 and 336G. In the low-frequency transient test at 5-100Hz, the board experienced forces of up to 20G.
The trio of shock tests measured, respectively, at 500Hz with typically 100 GSRS (Shock Response Spectrum of Gravity), 500 – 2.4kHz at 5.32 dB/oct. And lastly, 2.4 to 4kHz at an astounding 1,000 GSRS! The thermal vacuum tests were over a temperature range of -200C to 600C and cycled at +/- 2C per minute with a pressure of 1.33 mPa. The Spresense board showed no apparent damage or malfunction during or after the tests. In the proton irradiation tests, the board was subjected to proton bombardment at energies ranging between 10 and 70MeV for durations between 95 and 166 minutes and at fluxes of up to 1.742 x 107 p/cm2/s. Again, the results showed no significant adverse effects or damage other than requiring power-on resets, which means the board will need an aluminum shield to protect from radiation in a sun-synchronous orbit 500km above the Earth.
If Sony’s Spresense passes its satellite mission, it will then be used to control JAXA’s transformable robot on the surface of the moon on a mission slated for 2022. While on the moon, the robot will gather data on the lunar surface, which will aid in designing a crewed pressurized rover.