ASOLANT: In-Flight experiment

Project: ASOLANT In-Flight
Title: ASOLANT In-Flight experiment
Duration: October 2002 – March 2005
Prime contractor: LEMA-EPFL
Sub-contractor: OHB-System, Bremen (D)
Technical Partners: HTS (CH), CESI (I)

SATELLITE PLATFORM

The satellite platform consists in the payload adapter of a COSMOS rocket as depicted in Figure hereafter. The ASOLANT experiment will be “attached” to the payload adapter, placed on the upper stage of the rocket used to launch other satellites. After the detachment of all the satellites, the upper stage of the rocket will remain in a LEO orbit for some months. During this period the ASOLANT in-flight experiment will be performed and a maximum of data about the performances of the antennas and the solar panels will be collected. In particular the data concerning the evolution of the solar panels as well as the quality of the GPS reception will be broadcasted to the ground station and will allow a continuous monitoring of the ASOLANT antennas status.

Orbiter parameters:

Satellite orbit:                 Sun synchronous orbit, 98° of inclination
Orbit altitude:                 700 Km
Attitude:                         not stabilized satellite, three axis rotation
Satellite rotation:            estimated to be < 1°Sec. (data obtained by past COSMOS launches)
Satellite platform:           Cosmos last stage with payload adapter
Launcher:                       Cosmos
Launch site:                    Plesetsk, Russia
Launch date:                   September 27/28, 2005 (TBC)

COSMOS launcher

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Satellite platform

ASOLANT PAYLOAD

The complete ASOLANT experiment payload is composed by one payload unit and the two ASOLANT antennas. The telecommunication system of the payload includes the following instruments:

1.      GPS Receiver
2.      Orbcomm modem
3.      S-Band beacon transmitter
4.      VHF/UHF modem

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ASOLANT payload general structure

ASOLANT payload engineering model under test

ASOLANT ANTENNAS

Two different antennas have been manufactured and integrated with GaAs based solar panel. The first antenna has been designed for GPS reception while the second one for S-Band beacon transmission. In this way, both functionalities of transmitting and receiving will be tested in a real in-flight configuration. The main challenge of the design of the two antennas has been to apply to one single structure, the design and test procedures normally used for different devices: solar panels and antennas.
The manufacturing of the flight models of the two ASOLANT antennas has been subcontracted to HTS AG Wallisellen (Switzerland) and the solar cells have been provided by CESI Milano (Italy)

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Picture of the two ASOLANT antennas Flight Models

Solar panels

The structures of the solar panels used for the two antennas are identical. The panels are based on an epoxy FR4 plate where the solar cells interconnecting lines are etched. The solar cells are directly glued on the FR4 and connected to the lines with small interconnecting strips. The cells are connected in two strings each providing 9 V and 500 mA. At the centre of the panel, a zone of 170 mm X 170 mm has been let free of solar cells in order to allow the antenna radiation.
The solar cells have been measured during the different manufacturing phases and the power delivered by the two panels is 10 Watts per panel.
 

ASOLANT Solar panel structure

ASOLANT ANTENNAS UNDER TESTS

ASOLANT vibration test

ASOLANT antenna test

Publications

S. Vaccaro, C. Pereira, J. R. Mosig, P. de Maagt, " Flight Models Of Advanced Solar Antennas “Asolant”", 28th ESA Antenna Workshop on Space Antenna Systems and Technologies, Noordwijk (NL), 31 May - 3 June 2005.