ESA Solar Orbiter: Sunshield Undergoes extreme Solar heat test

ESA’s Solar Orbiter mission has undergone its latest major test: its protective shield has been subjected to concentrated sunlight to prove it can cope with the fierce temperatures close in to our parent star.

A ‘structural–thermal’ version of the craft’s sunshield was recently exposed to an artificial Sun for two weeks in Europe’s largest vacuum chamber at ESA’s Technical Centre in Noordwijk, the Netherlands.

The outcome ensures it will balance solar illumination, the cold of deep space and internal heat sources to maintain the perfect operating temperature.

Solar Orbiter, due for launch in 2017, sports a portfolio of instruments for in-situ measurements and high-resolution imaging of the Sun.

ESA’s next generation Sun explorer, Solar Orbiter will be launched in 2017. 

It will investigate the connections and the coupling between the Sun and the heliosphere, a huge bubble in space created by the solar wind. 

The solar wind can cause auroras and disrupt satellite-based communication.

The craft will probe to within almost a quarter of Earth’s distance from the Sun, suffering 13 times the intensity of terrestrial sunlight and temperatures of up to 520°C.

This means Solar Orbiter has been designed around its sunshield: a 3.1 m by 2.4 m sandwich of high-temperature multilayer insulation foil with a black-treated surface.

Openings allow sensors to peep through, some behind protective glass or beryllium.

The sunshield was installed in the 15 m-high and 10 m-diameter Large Space Simulator in May for testing.

Members of ESA’s Solar Orbiter team watch expectantly as an essential part of the spacecraft is lowered into Europe’s largest vacuum chamber: the multi-layered shield that will protect their probe from the Sun’s remorseless glare.

Part was blasted by a beam of simulated sunlight produced by 19 xenon lamps, each consuming 25 kW, and directed onto the shield via a mirror array.

Meanwhile, the chamber’s black walls were chilled by –170°C liquid nitrogen running through them to simulate the cold sky surrounding the craft.

The testing confirmed the design and checked the thermal computer model will accurately predict flight temperatures.

An infrared camera system monitored and measured the temperature of the shield’s front face in real time, along with heat sensors glued to various parts of the multilayer structure.

At the same time, precision ‘photogrammetric’ cameras looked for the slightest movement in the sunshield’s front face as it heated up.

NASA Space Shuttle Endeavour undergoes inspection by crew

Astronauts on the US space shuttle Endeavour on Tuesday finished routine inspection of the thermal protection system on the orbiter's wing leading edges and nose, NASA said.

The crew soared into orbit Monday carrying an observation deck for the International Space Station, a seven-windowed dome offering breathtaking views.

On much of their first day working in space, Commander George Zamka, Pilot Terry Virts and Mission Specialists Kay Hire, Stephen Robinson, Nicholas Patrick and Robert Behnken inspected heat-resistant tiles and reinforced carbon-carbon surfaces on those high friction areas.

"Zamka, Hire and Patrick used the shuttle's arm and its Orbital Boom Sensor System extension to survey Endeavour's right wing. Subsequently, Virts and Robinson joined the commander for the nose cap survey. Hire replaced Zamka for the port wing survey," NASA said.

The crew was looking for any sign of being hit by ice, and for foam insulation damage that in the past has plagued the external fuel tank. Images were beamed back to mission control in Houston, Texas, to be analyzed.

Some small bits of foam did break off two minutes after launch but apparently without harming the shuttle, Bill Gerstenmaeir, who is in charge of NASA space operations, said late Monday.

In addition to the heat tile inspection, which took about seven hours, the shuttle crew readied for its rendezvous with the ISS. Docking is scheduled for just after midnight 0506 GMT Wednesday.

The NASA Space Shuttle Endeavour pre-docking manouvre video