Open and shutter case

A tiny radiator to control heat emissions inside small satellites was launched aboard a test spacecraft last week, heralding a new generation of nano-satellites, claim its developers.

Created by researchers from the John Hopkins University Applied Physics Laboratory near Washington DC, the temperature control device — Variable Emittance Coating for Thermal Control (Vari-E) — is based on MEMS technology. The work was conducted in conjunction with NASA's Goddard Space Flight Centre.

The system actively controls how much heat the spacecraft emits into space by opening or closing the shutters on the radiator. The new shutters are micro-machined on to a highly emissive silicon substrate.

Opening the shutters allows heat from the spacecraft to be dispersed in the form of infrared radiation, as it exposes a section of this special silicon that readily emits heat.

The 9x10cm radiator comprises 36 chips, each fitted with 72 individual microscopic shutters. The shutters are controlled by six tiny comb-shaped motors powered by electrostatic charges.