All-reflective solar coronagraph sensor and thermal control subsystem

A coronagraph optical system for continuously imaging a wide field of view, the optical system comprising:

• a fore optics assembly having an entrance aperture positionable towards the Sun, the fore optics assembly comprising a plurality of mirrors that reflect light rays about a wide field of view centered around the Sun;
• an aft optics assembly configured to reflect the light rays to at least one sensor;
• a fold mirror optically coupled between the fore optics assembly and the aft optics assembly and configured to reflect the light rays to the aft optics assembly, the fold mirror having an aperture defining an angular subtense sized larger than the angular subtense of the Sun;
• and
• a thermal control system operably coupled to the plurality of mirrors and the fold mirror, the thermal control system comprising at least one radiator thermally coupled to a plurality of heat transfer shrouds, each spatially separated from, and radiatively coupled to, a respective one of the plurality of mirrors and the fold mirror to facilitate transfer of heat, such that a direct solar image can pass through the aperture of the fold mirror to the respective heat transfer shroud to absorb heat from a solar load from the Sun, and such that the entrance aperture can be continuously positioned towards the Sun.

A method for continuously imaging a wide field of view centered about the Sun using a coronagraph optical system, the method comprising:

• positioning an entrance aperture of a fore optics assembly of a coronagraph optical system towards the Sun, the fore optics assembly comprising a plurality of mirrors that reflect light rays about a wide field of view centered about the Sun;
• positioning an aperture of a fold mirror approximately toward a direct solar image of the Sun to at least partially remove a solar load on the coronagraph optical system, wherein the fold mirror reflects the light rays from the fore optics assembly to the aft optics assembly;
• and
• controlling a temperature of the plurality of mirrors and the fold mirror via a thermal control subsystem comprising a plurality of heat transfer shrouds each spatially separated from, and radiatively coupled to, a respective one of the plurality of mirrors of the fore optics assembly to progressively absorb heat from the plurality of mirrors from a solar load from the Sun, and wherein one heat transfer shroud is spatially separated from, and radiatively coupled to, the fold mirror such that a direct solar image can pass through the aperture of the fold mirror to the heat transfer shroud to absorb heat from the solar load from the Sun;
• and
• continuously pointing the entrance aperture towards the Sun.