1. www.altecspace.it All rights reserved © 2014 - Altec ExoMars 2018 Rover Operations Control Centre Decision making process, Communications and Planning Cycle D. Bussi

2. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr.  Communication Scenario and ROCC Planning Cycle  TGO / Rover link  Ground Stations Network  Drawback 1: Mars / Earth Delays  Drawback 2: synchronization with the Activity Plan  Expected timeline of the ROCC Planning Cycle Date Page 2 Table of Contents

3. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr.  The Exomars Rover will rely on the TGO orbiter for data link via deep space antennas on Earth. No direct from / to Earth link is available. Key assumptions are:  Rover position on Mars surface considering the candidate sites:  Mawrth Vallis  Oxia Planum  Hypanis Vallis  Aram Dorsum Date Page 3  The orbit and the RF communication characteristics of the relay satellite  The position of the available GSs on Earth (European and Russia Ground Stations) Decision making process, Communications and Planning cycle

4. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr. Date Page 4 The TGO orbital parameters have been provided by Prime / the Agency: 373:30 frozen Orbit. Two up to four TGO passages per sol are available for TGO and Rover communication. Most of the overflights are separated by 10-12 hours. The duration of each overflight is variable from few minutes up to 15 minutes (considering a minimum elevation angle Rover-TGO > 5 deg). LocationMawrth Vallis Oxia PlanumHypanis Vallis Aram Dorsum Number of passes [FY2019]1220118011341117 Minimum Pass Duration [s]20184023 Mean Pass duration [s]702700695690 Max Pass Duration [s]891887882877 Total relay Duration [h]238229219214 Decision making process, Communications and Planning cycle

5. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr. Date Page 5 To download the reference 150Mb / sol of TM expected from the Rover, the minimum duration of the communication window must be about 5 minutes considering an average bit rate of 256 Kbps (Rover to TGO). Decision making process, Communications and Planning cycle

6. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr. Date Page 6 The Rover operations are expected to start during martian morning (after Mars sunrise) and stop around sunset. The nominal approach is to send the TCs just after rover activation and receive telemetry just before rover sleep time. The operations cycle is simpler if we have a data relay that has a sun synchronous orbit (e.g. NASA MRO) Decision making process, Communications and Planning cycle

7. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr. Date Page 7 TGO overflights can instead occur with different timings from one day to the next. It is therefore possible to have passages synchronized with the rover activity, when TC uplink happens near sunrise - just after rover activation - and TM downlink happens after the end of the rover activities - just before sunset and its sleep time -. 1°Drawback: synchronization with the Mars Local Time (Rover daily activities) Optimal Passages Sub-Optimal Passages Decision making process, Communications and Planning cycle

8. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr. Date Page 8 The Exomars 2018 Mission will make use of the ESTRAK ESA network and of Russian Ground Stations. The reference Ground Stations for the mission currently are Malargue (from ESA DSN) and Bear Lake (from Russian DSN). The availability of the two Ground Stations is supposed to be optimized for the fulfillment of the EXM 2018 mission. ESA Deep Space Network Russian DSN Exomars candidate Stations Decision making process, Communications and Planning cycle

9. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr. Date Page 9 Another topic of the Rover / Orbiter / Stations configuration is the communication delay. Due to the Ground Stations location and their availability, the communication delay experienced by the ROCC is time dependent. The peaks of the latency are related to the ‘delayed overflights’, the ones not having a direct visibility with Earth (20%). In all the other cases (80%) the delay is contained within the 2 hours. 2°Drawback: variable delay of rover TM/TC data link Delayed Overflight latency peaks Nominal Overflight latency Decision making process, Communications and Planning cycle

10. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr. Date Page 10 The Planning Cycle at ROCC must be designed considering:  A variable synch with the communication windows with the Mars Time and the consequent sequence of activities of the Rover E. g. we could have to plan for the next sol activities before the end of the current sol or rely on planning of sol N+1 (done the sol before)  A variable delay of communication window which can have as a consequence a reduced time to conduct the science analyses and planning operations at ROCC We can have from a maximum of 7-9 hours (as NASA-MER operations) to a minimum of 4-6 hours (depending on the Ground Stations availability) Decision making process, Communications and Planning cycle

11. All rights reserved © 2014 - Altec www.altecspace.it Ref. Nr. Date Page 11 Preliminary teams availability assessment: due to different Mars vs. Earth timing and the TGO orbit:  at the beginning of the mission it should be necessary to have variable and flexible working shifts: we need the entire operations team at ROCC when the telemetry data arrive. Every team could start with operators specialized in one or few of tasks (e.g. data analysis, planning, data archiving) with daily work starting at a different time every day  later, during nominal operations, we will make use of fixed working shifts. All the operators must be trained to conduct every kind of jobs because the operations could shift their local starting time every day. Decision making process, Communications and Planning cycle