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The R2 mission
R2 before shipping
Mission
Technical demonstration of Exotrail’s ExoMG™ Hall Effect Thruster
Stakeholders
Satellite manufacturer and operator: NanoAvionicsCustomer and payload operations: Exotrail
Orbit
Launched from India on 7th November 2020Altitude: 571 km - Inclination: 36.9° - Eccentricity: 0.001
The R2 mission
Mission
Technical demonstration of Exotrail’s ExoMG™ Hall Effect Thruster
Stakeholders
Satellite manufacturer and operator: NanoAvionicsCustomer and payload operations: Exotrail
Orbit
Launched from India on 7th November 2020Altitude: 571 km - Inclination: 36.9° - Eccentricity: 0.001
R2 before shipping
The R2 mission
Mission
Technical demonstration of Exotrail’s ExoMG™ Hall Effect Thruster
Stakeholders
Satellite manufacturer and operator: NanoAvionicsCustomer and payload operations: Exotrail
Orbit
Launched from India on 7th November 2020Altitude: 571 km - Inclination: 36.9° - Eccentricity: 0.001
R2 before shipping
R2 before shipping
The R2 mission
Mission
Technical demonstration of Exotrail’s ExoMG™ Hall Effect Thruster
Stakeholders
Satellite manufacturer and operator: NanoAvionicsCustomer and payload operations: Exotrail
Orbit
Launched from India on 7th November 2020Altitude: 571 km - Inclination: 36.9° - Eccentricity: 0.001
6
Subsystem for gas distribution towards the thrusterhead
Propellant Management System
A Tank Assembly for propellant storageTanks
The thruster head generates the thrust. It hosts the anodeand cathode assemblies
Thruster Head
The command and control subsystemIt manages the power and the communication with thesatellite.
Thruster Control Unit
Propulsion system overview
7
Other subsystems
E l e c t r o n i c s
Power conversionBattery voltage → usable voltage for the thruster6-32 V input voltage
ControlCAN, RS485, RS422 communication protocolHighly configurable commandsComplete system monitoring with 15+ temperature monitored
Propellant storageStores high-pressure xenon gas in certified tanks for propellant density and increased thruster performance
Mass flow regulationRegulate the pressure and the mass flow to the thruster head
P r o p e l l a n t m a n a g e m e n t
8
Hall effect technology
(1) Electrons are emitted by the cathode
(2)They are captured inside the anode channel by a strong magnetic field
(4) The electron density locally generates a gradient
of electric field that accelerates the ions
(3) The electrons collide and ionize the propellant
(5) A fraction of the electrons are used to recombine
with ions in order to neutralize the plume
Xe+
e-
Thru
st/po
wer r
atio (mN/kW)
specific impulse (s)
10
25
50
0 1000500 3000
50 mN/kW | 1000 s
Good EfficiencyHighest Thrust
A high-thrust thruster
FEEPVATGITRFPT
RFPT
RFPT : Radio Frequency Plasma ThrusterGIT : Grid Ion Thruster
VAT : Vacuum Arc ThrusterFEEP : Field Emission Electric Propulsion
EXOMGTM
Commissioning of the satellite
Passive checks
power the propulsion unit for several days to gather data
Monitoring of the temperatureMonitoring of the power consumptionMonitoring of the propellant management system
Temperature of the control unit
Temperature of the thruster head
Pressure in the tanks
Commissioning of the satellite
Passive checks
power the propulsion unit for several days to gather data
Monitoring of the temperatureMonitoring of the power consumptionMonitoring of the propellant management system
Temperature of the control unit
Temperature of the thruster head
Temperature is within the acceptable limit for electronics and the CONOPS is not impacted
Pressure in the tanks
Commissioning of the satellite
Passive checks
power the propulsion unit for several days to gather data
Monitoring of the temperatureMonitoring of the power consumptionMonitoring of the propellant management system
Temperature of the control unit
Temperature of the thruster head
Temperature is within the acceptable limit for the thruster and the CONOPS is not impacted (no heating required)
Pressure in the tanks
Commissioning of the satellite
Passive checks
power the propulsion unit for several days to gather data
Monitoring of the temperatureMonitoring of the power consumptionMonitoring of the propellant management system
Temperature of the control unit
Temperature of the thruster head
10% of pressure oscillations and it remains well within design marginsThe pressure before and after launch indicates that no leak occurred in the meantime
Pressure in the tanks
Commissioning of the satellite
Active checks
Start-up procedure performed step-by-step
Controlling the mass flow to the anode and to the cathodePowering the cathode heater and the anode with trying ignitionTrying the first ignition
Cathode and anode mass flow
Cathode heating
Anode polarization
Commissioning of the satellite
Active checks
Start-up procedure performed step-by-step
Controlling the mass flow to the anode and to the cathodePowering the cathode heater and the anode with trying ignitionTrying the first ignition
Cathode and anode mass flow
Cathode heating
Anode and cathode mass flow are nominal and as calibrated on the ground
Two independent lines for the anode and the cathode with the possibility to control the mass flow in time Anode polarization
Commissioning of the satellite
Active checks
Start-up procedure performed step-by-step
Controlling the mass flow to the anode and to the cathodePowering the cathode heater and the anode with trying ignitionTrying the first ignition
Cathode and anode mass flow
Cathode heating
Cathode heating is nominal, as calibrated on the groundNo impact of launch on the heater
Anode polarization
Commissioning of the satellite
Active checks
Start-up procedure performed step-by-step
Controlling the mass flow to the anode and to the cathodePowering the cathode heater and the anode with trying ignitionTrying the first ignition
Cathode and anode mass flow
Cathode heatingAnode is polarized as expected
Anode polarization
Commissioning of the satellite
First ignition attempt
Cathode hotPropellant flowing through anode and cathodeAnode polarization
Nominal ignition of the thruster at the first trialFull duration firing of 10 minElectrical and propellant behavior as expected
18
Commissioning of the satellite
Executing the commissioning requires:
- A plan, with corrective actions in case something goes wrong- Many observables- On-ground references
19
Operations and performance estimation
Operations shared between 3 partners- Exotrail operates the payload and provide flight dynamics
solutions through its ExoOPS™ - Operations software- NanoAvionics operates the platform- Leaf Space operates the ground segment
EXOOPS™ - Operations
Events management
Telemetries monitoring
Commands generation
Flight Dynamics
Compute, display and give access to events (eclipses, nodes crossing, firings, etc.)
Store, arrange, display and create alerts on the data gathered from the payload and the platform
Generates commands for the payload and manage modes of subsystems of the platform
Handles orbit determination and maneuver planning
20
Operations and performance estimation
Satellite tracking is key
Results
SpacetrackTLE
Unscented Kalman Filter
Maneuver plan
Thruster telemetriesAOCS telemetries Operational
TLE
GPS NMEA
Mission Planning
Orbit wrongly estimated→ no contact with the satellite→ need for powerful orbit determination algorithms
Semi-major axis evolution during a maneuvering phase:Estimated from GPS dataGiven by TLE
Along track error during a maneuvering phase:Along track errorDates of TLE
21
Operations and performance estimation
Estimate the performance is key
Results
Firing # Expected thrust [mN]
Realized thrust [mN]
1 1.8 2.252 1.8 2.153 2.4 2.894 2.4 3.025 2.4 3.12
Thrust measured in-space higher than measured on the ground
Explanations: Facility effects – background pressure, conducting walls, etc.Thruster Performance
➢ Required for mission planning➢ Objective of a demonstration mission