European Space Agency

Contactless Angular Sensors for Telecom Satellites Long Lifetime Mechanisms

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Objectives

This project has studied the technological solutions available in the market for the potential implementation of a contact-less angular sensor for European telecommunication satellites applications, identifying the past problems with rotary sensors, the desired industry specifications and the expected market for the close to medium future.

After concluding that the best candidate technology is electric (capacitive) coupling the project team has identified a market product (from the Israel based Netzer Precision Motion Sensors Ltd) that provides rotary sensors for industrial applications and has developed an Elegant Breadboard with a completely new candidate sensing principle designed from scratch (and patented by the team) with the space environment in mind.

A test round with several pieces of each sensor has been conducted to investigate the validity of each concept for a future space qualified rotary sensor and specific studies about future spacialisation of the sensor developed under this project have been conducted.

The objective was to perform a technology survey in order to identify the main problems of present angular sensors, identify the main specifications and select the best technology to implement a contact-less technology for telecom space applications with up to 0.01o (16-bits) of accuracy. Once the technology is selected, obtain several representative working pieces and perform several tests, under relevant conditions of temperature, vibration and vacuum, to study the suitability of them for the development of a space qualified rotary sensor based on that technology.

Challenges

The review of available angular sensing technologies, with the feedback of actual problems of present ones provided by European angular sensors integrators, has lead to the selection of electrical (capacitive) coupling as a candidate for an angular sensor for telecommunication spacecraft.

Electrical coupling technology may produce the angular sensor with the expected requirements in size and robustness to be applied in solar array and antenna pointing mechanisms. Ion thruster pointing applications are also feasible. Test benches of two angular sensors based on this technology, one of them specifically developed within this project employing space qualified materials and space equivalent electronics, support the results.

Benefits

The development of an elegant breadboard of a new angular sensor (realised within the project using space qualified materials and space qualified equivalent electronics) based on electrical coupling, its testing under vacuum, temperature cycling and vibration (among other tests) and the preliminary worst case analysis, FMECA, part stress analysis, MTBF and response to SEU and SEL indicate that this technology may be used for the production of a space qualified angular sensor for space applications within European telecommunication satellites.

Features

Electrical (capacitive) coupling technology has been traded-off to have the most potential to implement an angular sensor that fulfils the needs of future European telecommunication satellites.

The study has concluded that a sensor based on this technology may be implemented using space qualified materials and electronic components.

The selection of a commercially off-the-shelf angular sensor, the development of a new sensor based on capacitive coupling within the project and the subsequent tests made on several units of both kind of sensors have given evidence (supported by preliminary WCA, FMECA and PSA) that a fully space qualified sensor based on this technology is feasible.

The development of a computer controlled test bench for this kind of sensors up to a resolution of 0,01o has also been achieved.

Plan

The project has been divided into the following work packages:

  • Identification of the past angular sensor failure mode in space applications.
  • Identification of potential contactless angular sensors for space applications.
  • Review of requirement specification and proposal of tentative specification for a space qualified angular sensor.
  • Screening of potential designs/technologies for space applications.
  • Trade-off and selection of technology for angular space sensors.
  • Development and Tests plan: implementation or purchase of technologies and implementation of test bench and data acquisition software.
  • Technology benchmarking (testing) and evaluation of technology suitability for space applications.
  • Road map for future development in order to produce a space qualified.

Current status

The study has been completed. Test results have been presented for one commercial (off-the-shelf) angular sensor and one angular sensor developed (and patented) within the project and preliminary studies of WCA, FMECA, PSA and MTBF for the developed sensor are also presented.

Contacts

Status date

Thursday, February 27, 2014 - 09:02