Gossamer structures for innovative space applications, such as solar sails, require technology that allows their controlled and thereby safe deployment. Before employing such technology for a dedicated science mission, it is desirable, if not necessary, to demonstrate its reliability with a Technology Readiness Level (TRL) of six or higher. The aim of the work presented here is to provide reliable technology that enables the controlled deployment and verification of its functionality with various laboratory tests, thereby qualifying the hardware for a first demonstration in low Earth orbit (LEO). The development was made in the Gossamer-1 project of the German Aerospace Center (DLR). This paper provides an overview of the Gossamer-1 mission and hardware development. The system is designed based on the requirements of a technology demonstration mission. The design rests on a crossed boom configuration with triangular sail segments. Employing engineering models, all aspects of the deployment were tested under ambient environment. Several components were also subjected to environmental qualification testing. An innovative stowing and deployment strategy for a controlled deployment, as well as the designs of the bus system, mechanisms and electronics are described. The tests conducted provide insights into the deployment process and allow a mechanical characterization of that deployment process, in particular the measurement of the deployment forces. Deployment on system level could be successfully demonstrated to be robust and controllable. The deployment technology is on TRL four approaching level five, with a qualification model for environmental testing currently being built.

The influence of growth temperature on the structural and magnetic properties of Heusler alloy Co 2 FeSi films grown on Si(111) substrates has been studied. Reflection high energy diffraction (RHEED), double crystal x-ray diffraction (DCXRD) and transmission electron microscopy (TEM) measurements revealed that Co 2 FeSi layers were epitaxially grown on Si(111) substrates in an optimized growth temperature rangeFrom double crystal x-ray diffraction measurements and transmission electron microscopy, it was shown that in the optimized temperature range the Co 2 FeSi/Si(111) films crystallize in the B2 + L2 1 structures. All layers are ferromagnetic and well-ordered films on Si(111) show high magnetic moments with an average value of (1140 ± 250) emu/cm 3 , which is in good agreement with the value of bulk Co 2 FeSi at 300 K. The magnetic anisotropy is correlated to the structural properties of the layers.

Information storage and monitoring relies on sensitive transducers with high robustness and reliability. This paper shows a methodology enabling the qualification of magnetic sensors for magnetic pattern readout, in applications different than hard disk magnetic recording. A magnetic tunnel junction MTJ sensor was incorporated in a reader setup for recognition of the magnetization of patterned arrays made of CoCrPt thin films and magnetic ink. The geometry of the sensor (in particular, the footprint and vertical distance to the media) was evaluated for two sensor configurations. The readout conditions were optimized to cope for variable media field intensity, resulting from CoCrPt film or magnetic ink thickness, with fixed reading distance and dimensions of the pattern. The calibration of the ink magnetic signal could be inferred from the analytical calculations carried out to validate the CoCrPt results.

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