HIREX Engineering Study

Project Overview:

Central Engineering is involved in a study to determine the feasibility of building an orbiting telescope capable of resolving 7 km structure on the sun. In order to achieve the required imaging the telescope must have a resolution 0.01arcsec. This fact challenges the state of the art of orbiting telescopes in several areas: The overriding telescope design concept is based on a 0.6m Gregorian-style telescope with a 240 meter effective focal length. This is achieved with 2 mirrors supported at opposite ends of a 35m space deployable boom. The telescope mirrors are coated with multilayers designed to reflect a broad XUV passband. A third, small mirror, near the focal plane performs the function of selecting the narrow band that is finally imaged. Image stabilization to the 0.005 arcsec level is achieved by active control of the secondary mirror.

The primary mirror is held unadjustably to the spacecraft, its pointing set by the spacecraft orientation. The secondary mirror is mounted on a 6-axis stage that permits its position to be changed to align the telescope in space. The stage is intended for intermittent adjustment, both because of its speed of travel, and the TBD alignment procedure. The third mirror is called the TXI (Tuneable X-ray Imager). It is mounted on a gimbal that permits it to be tipped over 60o range, selecting between the individual wavelengths in the initial bandpass. It can also rotated completely out of the way to allow the full, broadband EUV flux to strike the focal plane.

Finally, the focal plane assembly is designed to rotate on the outer edge of a circle centered on the TXI mirror rotation axis. This permits the focal plane to move to the location that the TXI redirects the light once it has been set to a given wavelength response.

Engineering Study Overview:

The engineering study is divided into the following areas: The work is being performed to the requirements called out in the Science Requirements document.

Questions, comments pcheimets@cfa.harvard.edu
Last Modified Friday, 17-Oct-2008 11:59:11 EDT