ATV-2 vessel engineering - briefing for the Media 9-Feb-2011

The ATV2 Flight Segment Media Briefing H.P. Leiseifer 09 February 2011

Table of Content
1. ATV2 Mission Objectives
2. ATV2 Lay Out and Design
3. ATV 2 Functions
4. Contingencies and Safety Aspects
4.1 System Requirements on Fault Tolerance and their Implementation
4.2 Manoeuvres
4.3 Re-Entry
5. Launcher & Launch Configuration
6. Inflight Services and Cargo
6.1 Refuelling
6.2 Water & Gas Delivery
6.3 Reboost
6.4 Dry Cargo
Acknowledgements
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Media Briefing- 1. ATV 2 Mission Objectives
Objectives and Mass Budgets
Propulsive Support to ISS including Re-boost, Attitude Control, Control Moment Gyro ( CMG) de-saturation and Debris Avoidance
Delivery of Cargo, Gas and Retrieval of Wastes
ISS refuelling
For Johannes Kepler the Mission mass budget is:
ATV Total Mass at Launch: 20060.5 kg – this includes
Mission & Reboost Propellant: 6565,6 kg
Propellant for Refuelling: 850,6 kg
Gas ( Oxygen): 100 kg
Integrated Dry Cargo : 2689,4 Kg ( Incl. 1084,3 Kg Racks)
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Media Briefing- 2. ATV 2 Layout and Design
Envelope and Mayor Constituents
ATV Overall Envelope
Compliant with AR 5 Fairing Constraints
Length:10773 mm ( including Adapter , 2000 mm)
Diameter:4482 mm ( max MDPS w/o MLI)
ATV Major Constituents
Integrated Cargo Carrier ( ICC) with
22 m3 of total pressurized module volume, shirt sleeve environment
16 m3 available for cargo accommodation
6 Integrated Light Racks ( ILRs )
2 Temporary Storage Racks (TSRs)
Russian Docking System, Active Part to dock to Russian Service Module of the ISS
Equipped External Bay ( EEB) with Refuelling System ( RFS) and Gas and Water Tanks , 3+3 ( Fluid Cargo)
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Media Briefing- 2. ATV 2 Layout and Design Cont’d
Meteorid and Debris Protection System ( MDPS)
Sensors for GNC Functions
Star Tracker , Videometers, Telegoniometer, Visual Video Targets, and Range Cues
Antenna H/W for Communication Function
Proximity Link Antennas
Antennas for TDRSS/Artemis Communication Chains
KURS Antenna for direct ATV – Russian Segment communication
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Integrated Cargo Carrier
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Russian Docking System
Media Briefing- 2. ATV 2 Layout and Design Cont’d Pag.

ATV Major Constituent Cont’d
ATV Spacecraft ( SC) with
Equipped Avionics Bay ( EAB)
Equipped Propulsion Bay ( EPB)
Separation and Distancing Module (SDM)
Solar Generator System ( Sun Tracking)
4 Solar Arrays with 22.3 m span, 8.4 m2 each, 4.8 KW power total
MDPS
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ATV Configuration Drawing( w/o SDM)
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Media Briefing 2. ATV 2 Layout and Design Cont’d
ATV Overall View
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ATV Equipped Avionics Bay
Exploded View
Pag. Media Briefing 2. ATV 2 Layout and Design Cont’d VCHP other trays Radiators other trays Radiators batteries Trays Avionics equipment VCHP batteries

ATV 2 Equipped Avionics Bay - View Inside
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Media Briefing -2. ATV 2 Layout and Design Cont’d
ATV 2 Equipped Propulsion Bay
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ATV 2 in CSG ( Kourou) Integration Hall
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Media Briefing- 3. ATV 2 Functions: Propulsion
Bipropellant System with Monomethyl-Hydrazine ( MMH) as Fuel and Mixed Oxygen Nitrogen (MON) as Oxidizer
MMH and MON are stored in 4 + 4 tanks, pressurized with He ( 2 Tanks)
4 Main Thrusters ( 400 N engines) located at ATV aft ( opposite the Docking System location ),
20 AOCS Thrusters ( 200 N engines), assembled in
4 Clusters with 5 thrusters each
8 Front Attitude Control Thrusters ( 200 N engines), assembled in
4 Clusters ATV Front Cone (Docking Adapter side ), with 2 thrusters each
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Media Briefing-3.ATV 2 Functions: Propulsion Cont’d Pag.

Media Briefing-3.ATV 2 Functions: Propulsion Cont’d
ATV 2 Main Thruster View during Assembly ,Integration and Test
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Media Briefing-3.ATV 2 Functions: Power
The ATV Power System is composed of 4 identical completely independent power chains including
4 solar wings, each consisting of 4 panels; every solar array wing is provided with a rotating drive mechanism (SADM)
4 PCDUs that distribute power with a regulated voltage to the avionics units and with non-regulated voltage to the heaters; each PCDU receives power from one panel of each solar wing
4 rechargeable (NiCd) batteries, each with 40 Ah capacity
4 non-rechargeable (LiMnO2) batteries for MSU (segregation) and RSCE (high power peaks)
4 PCUs connected to PCDUs which provide regulated power to MSU, RECS and KURS equipment
Pag.

Media Briefing-3. ATV 2 Functions: Power Cont’d Pag.

Media Briefing-3. ATV 2 Functions: Thermal Control
The Main Features of the ATV Thermal Control Concept are:
Passive Thermal Control utilising Multi Layer Insulation ( MLI) and Constant Conductance Heatpipes (ICC and EPB)
Active Thermal Control utilising Heater System to keep the ICC shell Temperature within Specification
Active Thermal Control utilising Variable Conductance Heatpipes and Radiators for Electronic Boxes of the Equipped Avionics Bay
Pag.

Media Briefing-ATV 2 Functions Datamanagement & Software
Datahandling System architecture based on
Fault Tolerant Computer ( FTC ) with 3 Data Processing Units , ATV internal MIL Bus System and MIL Bus I/Fs to SM/ISS
FTC is 2 Fault Tolerant , dedicated to nominal operations including Failure Detection Isolation and Recovery ( FDIR)
Monitoring & Safing Unit ( MSU) which is dedicated to the independent Proximity Flight Safety function to ensure ISS safety
Flight Application Software (FAS) runs on FTC and the associated Soft Ware Units.
For the FAS Category C SW has been accepted
The MSU Software is Category A, since here Safety Critical Functions are managed with potentially catastrophic consequences and no adequate means of intervention.
Pag.

Media Briefing- 3.ATV 2 Functions Datamanagement & Software Cont’d Pag.

Media Briefing-3. ATV 2 Functions: GNC
The ATV Navigation. Guidance and Control function, encompassing ATV Flight Control and Flight Control Monitoring, is implemented in the Flight Application Software
Based on the measurements obtained by the GNC Measurement System (GMS):
4 Gyrometers and 2 Startrackers for attitude measurement during free-flight and phasing
4 accelerometers for monitoring the ATV boosts during orbital manoeuvres
2 GPS receivers for relative (RGPS) navigation with ISS starting from 50-30 km distance from ISS
2 digital camera sensors (Videometers) for relative position and (from 30 m) relative attitude measurement during final docking approach starting from 300 m distance
2 laser range finders (Telegoniometers) for monitoring the GNC performance in relative position, range and range-rate to Station
Pag.

ATV GNC Architecture
Media Briefing-3. ATV 2 Functions: GNC Cont’d Pag.

Media Briefing-ATV 2 Functions: Communications
Two segregated RF chains, one redundant one for comm’s with the ATV CC via TDRSS link, and one redundant for the proximity comm’s link to ISS
2 TDRSS link chains (1 kbps TC data rate, 8 or 64 kbps TM data rate 30W transmitted output power
2 transponders (receivers in hot, transmitters in cold redundancy)
3 S-band TDRSS antennas, one dedicated to the nominal chain pointing towards nadir, two for the redundant chain, with one pointing towards nadir and one towards earth
1 Switch to select the nadir or the earth pointing antenna in the redundant TDRSS chain
2 PROX link chains (20 kbps TM and TC data rate, 5 W transmitted output power
PLAST transponders (receivers in hot, transmitters in cold redundancy)
2 PROX antennas, one nadir pointing, one earth pointing
2 CPFs in hot redundancy for HLTCs and HLTMs, and in cold redundancy for other commands and telemetry.
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Media Briefing- 3.ATV 2 Functions: Communications
ATV Communications Architecture
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Media Briefing- 3.ATV 2 Functions: Communications
ATV Overall Communication Paths
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Media Briefing-4. ATV 2 Contingency & Safety Aspects
System Requirements on Failure Tolerance
1. no single failure or operator error shall have major or critical or catastrophic consequences
2. no combination of either:
- two failures, or
- two operator errors, or
- one failure and one operator error,
shall have catastrophic consequences
Pag.

Media Briefing-ATV 2 Contingency & Safety Aspects Cont’d
Main Features of Implementation of Fault Tolerance in the ATV Avionic
System
4 segregated power chains (SGS chains, Batteries, PCDUs, PWR buses)
4 1553 MIL-bus data buses
2FT computer (3 voting DPUs, each one able to take control of every data bus)
After the loss of 2 functional chains the vehicle is still able of SURVIVAL; however ATV operation in ISS vicinity may not be safe any more
ISS safety in this case is guaranteed by a completely independent safety system (Proximity Safety Function - PFS) ), which will execute a Collision Avoidance Manoeuvre (CAM) that propels ATV out of the ISS proximity
Pag.

Media Briefing- 4.ATV 2 Contingencies & Safety Aspects Cont’d
Manoeuvres
Flight Control Monitoring performs a fine monitoring to detect any potential dangerous trajectory towards the ISS due to Failures not detected by FDIR. Depending on the anomaly, and the Mission Phase there is triggering of a
Wait Manoeuvre
Escape Manoeuvre
Enabled as soon as Proximity Operations are staring ( 30 km distance to ISS)
Handled by the nominal System
Ensures a Delta V such that for 24 Hours ATV and ISS trajectories are apart
Collision Avoidance Manoeuvre (CAM)
Same as Escape however
Handled by the MSU , since the nominal system is not capable anymore to handle the anomaly
Pag.

Media Briefing-4. ATV 2 Contingency & Safety Aspects Cont’d
Re-entry
The nominal re-entry is performed after ATV-2 de-docks from the ISS. It then goes to a 381x220 km intermediate orbit. The re-entry may take place in daily repeat orbit 4.
The general situation is shown in the first picture ( ATV 1 case ) . Also to define the South Pacific Ocean Unpopulated Area (SPOUA ) applicable to ATV.
The footprint of the ATV 2 re-entry case is shown in the next picture and fits perfectly inside theSPOUA
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ATV 1 Re-entry Pattern
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ATV 2 Re-entry Pattern
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Media Briefing-5. Launcher & Launch Configuration
ATV to be launched on top of Ariane 5 Launcher
Flight V 200, Scheduled for 15 February 2011
Configuration: A5 ES
Long Fairing
2 Solid Rocket Boosters (“welded”)
EPS Uperstage
ATV Mounted onto A 63936 Adapter “Separation and Distancing Module “ (SDM) which constitutes the ATV to 5 Interface
Pag.

Media Briefing- 6. ATV 2 Inflight Services and Cargo
Refuelling
2x148.3 kg Unsymmetrical-DiMethyl-Hydrazine (UDMH )as Fuel
2x277 kg Nitrogen-TetraOxyde (NTO) as Oxydizer
Automatic ISS refuelling through Docking Adapter
Water& Gas Delivery
100 Kg Oxygen as ISS supply
Provided via Gas Control Panel – Crew operated
ATV 2 mission does not provide for Water , tanks will be filled with liquid waste before de-docking via Water Control Panel – Crew operated
Reboost
Currently 9 reboosts are planned , the first one is likely to happen shortly after docking
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Media Briefing- 6. ATV 2 Inflight Services and Cargo
Gas Control Panel
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Media Briefing- 6. ATV 2 Inflight Services and Cargo Cont’d
Water Control Panel
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Final mass of ATV-2 is 20,060 kg
6 Integrated Light Racks
4 M-01 bags mounted
64 Cargo Transfer bags (CTBs) + 4 M-01 bags integrated
in 4 lower racks during nominal
loading
29 CTBs integrated in 2 upper racks during late load, 13 days before launch
Late load cargo mass reached maximum loading target
Pag. Fluid Cargo Loading ATV-2 [kg] ATV-1 [kg] Mission Propellant 2030 3598 ISS Propulsive Support 4535 2260 Water 0 267 Gas (3 tanks: Oxygen) 100 20 Refuel Propellant 850.6 860 Total Fluid Cargo 5486 3407 Dry Cargo Loading Nominal Load Cargo (Integrated 17 Sep 2010) 1170 1150 Late Load Cargo (Integrated 28-29 Jan 2011) 435 No late load for ATV-1 Total Dry Cargo 1605 1150 Total Cargo Fluid + Dry 7091 4557

Media Briefing- 6. ATV 2 Inflight Services and Cargo Cont’d Pag. Geoflow2 Columbus Power Distribution Unit (PDU) Cargo Type Utilization Mass 204.58 Spares 555.59 Supplies (hygiene, batteries, cleaning) 181.72 Tools 26.52 Clothing 48.09 Food 519.94 PR Items 14.73 Other 54.18 Total 1605.35

M01 Bag Loading
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Media Briefing- Acknowledgements
Thanks to
K. MacDonell
H. Wartenberg
F.Bouckaert
F.Caramelli
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ATV-2 vessel engineering - briefing for the Media 9-Feb-2011

by ESA/ESOC - Darmstadt, Germany

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