Patrick Meras

Metrology system for measuring mast motions on the NuSTAR mission

A metrology system designed and built for the NuSTAR mission is described. The NuSTAR mission is an orbiting X-ray telescope with a 10 meter focal length. The system consists of two laser pointers mounted rigidly together with a star tracker and the X-ray optics. The focused laser beams illuminates two metrology detectors mounted rigidly with the X-ray detectors. The detectors and optics/lasers are separated by a ∼10 meter deployable (and somewhat flexible) carbon fiber mast. Details about the implementation of the metrology system is discussed in this paper. 12

Calibration and alignment of metrology system for the Nuclear Spectroscopic Telescope Array mission

A metrology system to measure the on-orbit movement of a ten meter mast has been built for the Nuclear Spectroscopic Telescope Array (NuSTAR) x-ray observatory. In this paper, the metrology system is described, and the performance is measured. The laser beam stability is discussed in detail. Pre-launch alignment and calibration are also described. The invisible infrared laser beams must be aligned to their corresponding detectors without deploying the telescope in Earth’s gravity. Finally, a possible method for in-flight calibration of the metrology system is described.

Qualification and selection of flight diode lasers for the NuSTAR space mission

Reliability and lifetime of diode lasers is critical to space missions. 12Rigorous tests were conducted on diode lasers to qualify them to be deployed on the Nuclear Spectroscopic Telescope Array (NuSTAR) mission. This mission includes a metrology system that is based upon 2 laser diodes. This paper discusses the different laser diode failure mechanisms that can arise, as well as laser diode reliability requirements set forth by the NuSTAR space mission. In addition, the space qualification procedures and results on 120 laser diodes from two different vendors will be presented. Also, the results of an accelerated laser lifetime test of 20 laser diodes, along with the flight laser diode selection process will be described in this paper.

Design, Qualification, Calibration and Alignment of Position Sensing Detector for the NuSTAR Space Mission

A commercial position sensing detector (PSD) has been used to measure mast deflections on a space based X-ray telescope (NuSTAR). This paper describes the space qualification process for utilizing a commercial PSD sensor in space. This discussion includes packaging, environmental testing, selection of flight candidate devices, calibration and alignment.

Compact and Robust Refilling and Connectorization of Hollow Core Photonic Crystal Fiber Gas Reference Cells

A simple method for evacuating, refilling and connectorizing hollow-core photonic crystal fiber for use as gas reference cell is proposed and demonstrated. It relies on torch-sealing a quartz filling tube connected to a mechanical splice between regular and hollow-core fibers.

Field Testing of Lunar Access and Navigation Device (LAND)

A laser radar system has been constructed. It is based on a commercial PC with digitizer, pulse delay instrument, National Instruments IO card and an optical head from a previous laser radar program. The laser radar was mounted on a gyro stabilized gimbal on the nose of a helicopter and flown in the Mojave Desert in September 2006. The collected data will be used to test algorithms for future precision lunar landers, which may be utilizing a laser radar as the primary landing sensor. This paper will describe the laser radar and PC based acquisition system used for the data collection, and provide an overview of the supporting test sensors and architecture. Preliminary data collected during the helicopter field testing will also be presented.