1 ESA ground antennas and their compatibility with the MORE experiment R. Maddè, M. Mercolino ESA/ESOC

MORE Team meeting, February ESA deep space network v ESA deep space network consists of two stations –New Norcia (NNO) DSA-1, operational since 2001, western Australia S- and X- band uplink and downlink capabilities Ka-band downlink optional (not yet taken) Currently supporting Mars Express (MEX) and Rosetta –Cebreros (CEB) DSA-2, operational since 2005, Spain. X- band uplink and downlink, Ka- band downlink capabilities Ka-band uplink optional (not yet taken) Currently supporting Venus Express (VEX) Cebreros will be the station supporting BepiColombo v Future deep space station –DSA-3 mat be located in the southern hemisphere at American longitudes (Chile or Argentina) X- band uplink and downlink (baseline), Ka- band downlink (optional)

MORE Team meeting, February Cebreros block diagram

MORE Team meeting, February Detail of the back-end (Rx side only) v Ka-band D/C output BW: 220 MHz v X-band D/C output BW: 100 MHz v L-band D/C output BW: 30 MHz v 3L-band D/Cs per station v 3 IFMS per station (2 for TT&C and 1 for RSI) 8400 – 8500 MHz RHC LHC – MHz RHC LHC X-band D/C L-band D/C 1 Switching Matrix IFMS1 CFECFE GDSP MHz 70 MHz Each input BW: 28 MHz L-band D/C 2 GDSP Test UCPU Estrack LAN Ka-band D/C Switch MHz

MORE Team meeting, February Back end – Receiver (IFMS) v IFMS characteristics –Input BW: 28 MHz (High-speed mode) –IF at 70MHz –CFE (common front end) samples at 280 Ms/s v Open loop capabilities –Sampling rate from 1kHz to 4MHz –Quantisation levels: 1,2,4,8,16 bits –Up to 4 channels per each DSP card v Ranging capabilities –Maximum ranging tone frequency at 1.5 MHz (as per ECSS and CCSDS standards)

MORE Team meeting, February MORE requirements (generals) v Unlike most scientific experiments mounted on ESA missions, MORE heavily involves both space and ground segment v Different requirement “levels” can be defined v PI “level 1” performance requirements are the “end-to- end” requirements v A set of “level 2” performance requirements has been prepared by the PI, with the intention to apportion them to the space and ground segments v Some “level 2” requirements are related to media calibration

MORE Team meeting, February MORE requirements (level 2) v MORE requirements can be split into four main areas: 1.Requirements on the needed multi-frequency link 2.Requirements on Doppler performance (all links) Ka/Ka link: adev (1000 s) < 6* Other links: σ X/X / σ Ka/Ka =4; σ X/Ka / σ Ka/Ka =10 3.Requirements on media effects Uncalibrated contribution adev (1000 s) < 1* (or 3* ??) (all media) for antenna elevation > 15 deg 4.Requirements on Ranging performance (all links) Ka/Ka ranging calibration error shall be less then than 0.3 ns (1 σ, 1-w) over half a day (X/Ka and X/X: 1.5 ns) Ka/Ka, X/X and X/Ka ranging signals shall be as defined in the SGICD (WBRS – either with tone or PN codes) Question for PI: are “ageing” requirements intended for the Ground Segment as well?

MORE Team meeting, February Current compatibility of MORE requirements with DSA 1. Need for a multi-frequency link –Imply a station Ka-band uplink upgrade (A in the next chart) 2. Requirements on Doppler performance (all links) –Imply the adev characterisation of the station on all links (B) –Imply the evaluation of the mechanical noise contribution (B) 3. Requirements on media calibration –Imply the use of an ad-hoc calibration system (which does not exist in ESA stations) (C) 4. Requirements on ranging performance –Imply the development, deployment and validation of a wide- band ranging processor (D) –Imply the development of a proper calibration strategy & the conduction of related test campaign (E)

MORE Team meeting, February Implementation approach List of needed activities: A. Ka-band transmission implementation B. Assessment of ADEV performance of the station C. Media calibration D. WBRS (Wide band ranging) processor E. Ranging calibration Ancillary activities F. Check station location accuracy G. Extension of station baseband capabilities

MORE Team meeting, February Ka-band transmission v What has been done –High stability Ka-band up- and down-conv. are available –Ka-band feed, mirrors and dichroic are in production –Development of a movable mirror, to squint Ka-Tx beam respect Ka-Rx beam, on going v What needs to be done –Development of the transmitter HPA –Production and procurement of 2 operational units –Installation of all Ka-band uplink elements in CEB –Test and validation campaign –Verification of the Ka-band uplink stability

MORE Team meeting, February Assessment of ADEV performances of the station v An end-to-end assessment on all the three links is required v What has been done –At station level, a tool has been developed to compute the ADEV of the station, given the measurements of each of the equipment (X/X link only) –ADEV characterisation has been performed in both NNO and CEB (not taking into account the antenna mechanical noise) –Development of system able to assess antenna mechanical noise (to be deployed and validated in a test antenna in Villafranca) v What needs to be done –Evaluate CEB mechanical noise –Evaluate overall adev of X/X link, once mechanical noise is known –Evaluate overall adev of X/Ka link, once mechanical noise is known –Evaluate overall adev of the Ka/Ka link, once the antenna is upgraded

MORE Team meeting, February Measured ADEV performances Measured Ka-band UC ADEV < 1*10 -16

MORE Team meeting, February Measured ADEV performances Measured Ka-band DC ADEV of 1*10 -16

MORE Team meeting, February Measured ADEV performances (CEB X/X) The MORE X/X adev requirement is 2.4* s

MORE Team meeting, February Media calibration v The effect of dispersive media will be almost totally cancelled by means of the multifrequency link v Requirements on the level at which troposphere effects have to be calibrated have to be frozen v The current requirements are not enough to define the needed system v There is the need to define the system in terms of –Technical performance –Station interfaces –Interfaces to the final user v What has been done –Nothing v What needs to be done –Study and assessment of technical specification of the needed media calibration system –Development and procurement of the operational system –Installation, testing and long term calibration of the operational system

MORE Team meeting, February v Both the proposed MORE ranging systems (with tone at 20MHz or using PN codes) require the development of a new TT&C platform v This platform shall anyhow be developed due to obsolescence of the current IFMS (in operation since 2001) v What has been done –Nothing v What needs to be done –Study on new wide-band TT&C processor –New wide-band TT&C processor development –New wide-band TT&C processor procurement –Procurement of operational units –Installation and test of new TT&C processor in CEB WBRS processor

MORE Team meeting, February Ranging calibrations v Requirements on ranging calibration need some further clarifications v ESA has never faced requirements on ranging calibration so stringent. Therefore, ranging calibration achievable accuracies have to be further characterised v What has been done –Some preliminary test campaigns on the existing links (X/X, X/Ka) v What needs to be done –Requirement analysis and test with the current available equipment –Based on the outputs of the characterisation of the current ranging calibration system, one may consider further activities (if needed – i.e. On-line ranging calibration)

MORE Team meeting, February Check station location v The ADEV contribution due to the uncertainty of the station location is required to be less than 1.2* s. This means a sub-centimetre accuracy (0.9 cm) in the station location. v The declared accuracy of ESA deep space antennas is in the order of 1-2 cm over short time periods. v Over long time periods, the effect of the tectonics movement must be taken into account. v Too little data available to characterise the tectonics movement in CEB. v A survey using DDOR/VLBI techniques for evaluating the station coordinates may be considered. This possibility is at the moment TBD.

MORE Team meeting, February Extension of station baseband capabilities v The advent of a new ranging processor has high impact on baseband station integration v The number of receiving/transmitting chains (and related connectivity to the RF equipment) shall be reviewed, depending upon the final mission operational requirements v Once this is clear, and the new processor produced, an upgrade of the baseband configuration shall take place

MORE Team meeting, February Tentative schedule ITEMTimeline A. Ka- band Tx implementation – Development2007/08 A. Ka- band Tx implementation – Production2009/10 A. Ka- band Tx implementation – Ka- u/l installation in CEB2011/12 B. Assessment of ADEV - ADEV of mechanical noise2008 B. Assessment of ADEV - ADEV of CEB in al llinks2008/2012 C. Media calibration – Study2007/08 C. Media calibration – System development2009/10 C. Media calibration – Installation, verfication, calibration2011/12 D. WBRS – Ranging processor – architectural study2008 D. WBRS – Ranging processor – development2009/10 D. WBRS – Ranging processor – procurement2011 D. WBRS – Ranging processor – integration2012 E. Ranging calibration – System characterisation2008 E. Ranging calibration – On-line ranging calibrationTBD F. Check of station location2008 G. Baseband integration2012

MORE Team meeting, February Schedule assumptions v The main assumption is to have the station ready 6 months before launch v Launch is currently scheduled for August 2013 v It has to be noted that the station is operational, and would require major upgrade (i.e. a considerable down- time) v  In order to minimise operational impacts, all integration activities shall be grouped in the same time period

MORE Team meeting, February Costs v This presentation does not talk about costs v It just shows how MORE needs can be mapped in the existing ESA infrastructure v However, it has to be noted that: –All that has been mentioned under “what has been done” has been covered by ESA –Most of what has been mentioned under “needs to be done” is currently not financed v The PI is invited to acknowledge the above-presented current status

MORE Team meeting, February Final remarks v ESA CEB station would welcome to host the ground segment of the MORE experiments v CEB is an operational station, used to support several missions. Therefore: –Station configuration is ruled by ESA –Station operation is restricted to ESA –Interfacing to experiment data has to be done through ESA v CEB station will provide in any case routine operations to the BC mission