JAXA scientists say they hope to be ready to launch the probe which is at present unnamed in Jun 2014.
According to the Japan Aerospace Exploration Agency, the mirrors will help the probe to survive temperatures on the surface of the planet, the sun's nearest neighbour.
The craft is about 6 feet high and is powered partly by solar energy collected by panels that are wrapped around its body. It is designed to constantly rotate to prevent one side becoming too hot.
The JAXA team, has calculated that by reflecting the intense heat of the sun, the temperature of the mirrors can be kept at about 160C.
Further tests are carried to determine the craft"s ability to withstand extremes of temperature
JAXA, is Japan's national aerospace agency and it is responsible for research, development and launch of satellites into orbit. Its motto is "Reaching for the skies, exploring space."