They must be the two most audacious space missions currently in development. Solar Orbiter and Solar Probe Plus will venture inside the orbit of Mercury to study the Sun. The temperatures on the front surfaces of these satellites will go into the high hundreds of degrees Celsius, and beyond. You could say they are the missions to Hell. Designing the systems needed to protect the spacecraft has stretched the minds of engineers. They both require heatshields, of course. For the European Space Agency's Solar Orbiter (SolO), it is a titanium solution. For the American Solar Probe Plus (SP+), it will be a carbon-composite material. Their instruments will have to cower behind these barriers to make the measurements that scientists hope will unlock some of the Sun's enduring mysteries. Both missions appear to be making good progress. The US space agency has just selected the rocket to launch Solar Probe Plus. A mighty Delta-IV Heavy - the biggest rocket in the world - will hurl this 610kg satellite towards the Sun in late 2018. And European industry - in the form of Airbus Defence and Space - has announced that it has now produced what it calls a structural and thermal model of Solar Orbiter. This is a kind of copy of the satellite, with representative instruments. It will be heated, blasted with sound, shaken and shocked to validate its design. If the copy survives the assault, engineers will know the flight model should also stand up to the extremes it will face in the real environment of space. More via BBC News.
The auction has been closed.