USA space exploration began in October 4th 1957 and on March 17th of 1958 the Naval Research Laboratory launched the world’s first solar-powered satellite, Vanguard 1. Four months later on 29 July
Recently, NASA made history again with the Mars landing of the InSight Mars Lander, which will study the interior of the 4.5 billion years old planet Mars for the very first time. This will provide valuable scientific information in preparation for future missions to the Moon and later to Mars.
NASA was challenged to design strong, lightweight and compact solar arrays that could supply considerable and continuous electrical power to the lander in an atmosphere with very low levels of sunlight. Consideration was paid to the solar array’s weight, whilst ensuring they were large enough to produce the necessary power to operate all functions of InSight.
Orbital ATK developed and integrated EMCORE’s solar panels into the UltraFlex solar arrays, an accordion fanfold flexible-blanket solar array comprising ten interconnected triangular gores, that when extended, forms a shallow umbrella membrane 2.15 meters in diameter with solar cells attached.
The SolAeroZTJ triple-junction solar cells within the arrays integrate several layers of semiconductor material into a single structure that converts more of the light spectrum to electrical power. The solar cell can attain 28% efficiency, providing enough energy to complete all works. It is only a few years ago that this level of solar cell efficiency would have been considered impossible to achieve. It is expected the panels will provide 200W – 300W under unfavourable conditions and up to 700W under favourable conditions.
David Messner, the Vice President and General Manager of Solar Arrays and Deployables for ATK’s Space Components division said, “Missions of this magnitude require extremely high reliability and proven performance”
The mission would not be possible to accomplish without the fan-like solar panels, specially designed for Mars’ weak sunlight, but the InSight’s batteries also play an important role in the mission.
Mars has extreme changes in the surface temperature, near the equator range from -110°C to 35°C. External battery heaters and radiators help to bring the lower limit up to -30°C to -20°C.
NASA is utilising the same battery technology that they have been using for many years. There have been some major advancements in this technology since 2002, so the InSight mission has new generation chemistry on board. The InSight’s batteries are Li-ion nickel-cobalt-aluminum oxide chemistry (NCA). The NCA has shown significantly better capacity and stability and can operate in a range of temperature from -30°C to 35°C.
Because of NASA’s good track record with the solar powered Mars rover Opportunity, it is expected that the InSight Mars Lander will stay in commission for more than the Martian year that it is design for.
“The best of NASA is yet to come, and it is coming soon” said the Administrator of NASA, Jim Bridenstine.