Félix Cuervo

Alphasat Aldo Paraboni payload IOT campaign and status after the first year of operation

The Alphasat satellite was launched on 25 July 2013. The Aldo Paraboni technology demonstration payload, funded by ASI under ESAs ARTES Programme, was embarked as an hosted payload on Alphasat. This Technology Demonstration Payload (identified as TDP5 and recently renamed “Aldo Paraboni”) was implemented under an ESA contract awarded in co-contractorship to Space Engineering and Thales Alenia Space Italia (TAS-I) which conceived the experimental mission and industrialised the subsystems. The Aldo mission is composed of two main elements: a Communication Experiment mission, which aims at assessing the performance of communication links at Q/V Bands; and a Scientific Experiment mission implemented through two beacons at Ka and Q Bands, which aims at characterizing propagation phenomena at these frequencies. During the In Orbit Test campaign of the above two mission components, TDP5 demonstrated compliance to the requirements and the nominal conditions of the Payload. The main topics of this paper are the description of the In Orbit Test requirements and the discussion of tests results. The good health of the Payload is demonstrated by the agreement of the results with the predictions that were calculated on the basis of the results of the on ground test campaign. The Commissioning and IOT campaign of Aldo Paraboni was performed over 3 distinct sessions: · Commissioning: 17-18 September 2013 · IOT Part 1: 10-18 October 2013 · IOT Part 2: 4-8 November 2013 This work is only related to the verification of the performance of the space segment, the Q/V-Band Payload, also referred to as the TDP5. TDP5 stands for Technical Demonstrator Payload #5 and it is formally the 5th experimental (i.e. technological demonstrator) hosted payload of the Alphasat programme.

Averaging aspects in short term forecasts of tropospheric attenuation

At cruising altitude airborne satellite connectivity is unproblematic since no clouds or precipitation occur above the aircraft. The critical portions of the flight are directly after take-off and before landing, where especially rain can severely influence microwave signals. In short term forecasts of precipitation high rain peaks may not be resolved due to the inherent averaging of forecasts. Here we present an empirical study to illuminate the deviations of forecasted data from high resolution rain rate measurements of a distrometer situated in Graz, Austria. The forecasts are simulated by averaging over the measured data to create ideal conditions. The focus lies on the averaging effects only; the forecast algorithm itself is not examined. The integration time is adapted to reflect available forecast data in Austria. In addition, potential limits for the deviations between high resolution time series of rain rates and average values of whole periods are discussed.