1. 1 wp4 – Technical Issues for payload integration within the Nacelle for High Altitude flight Budapest 24/11/04 Marco Bobbio Pallavicini Carlo Gavazzi Space SpA

2. 2 Aerial System Engineering and Integration Aerial System engineering and integration for designated flight mission Nacelle structural design (SD) and mechanical integration of the PL systems Thermal design (TD) of the system, to be operated within defined flight envelope Design and integration of the Electrical Power System (EPS)

3. 3 System Design – High Altitude Aerial System All the subsystems necessary for flight mission operation will be hosted in modules within the Upper part of the Stratospheric Carrier The Nacelle will be dedicated entirely to hosting of the two PL systems and the related Electrical Power System Nacelle will be integrated and handled separately from the upper part of the Stratospheric Carrier up to the launch pad pre-flight display Interfaces between the upper carrier and the nacelle are limited to a mechanical joint and three RS422 connections Desired weight of the fully integrated and equipped nacelle is 130kg

4. 4 Structura Design – Nacelle Aluminium mainframe Mechanical I/F for subsystem installation (possibly adjustable for modular re- utilisation) Four belts to connect corners of the mainframe to the joint to upper flight chain Thermal covers for passive thermal control and protection against radiation Protection elements for landing

5. 5 SD – Preliminary Geometry Definition Volumes allocation for PL system have been preliminary agreed (figure includes margins for internal thermal covers, if necessary) RF PL: 400 x 500 x 300 mm OPT PL: 500 x 600 x 1000 mm Both the PL systems require a wide- angle (TBD) free field nadir pointing Electrical Power System will be integrated after installation requirements from PL systems, considering CoG desired location (balance and stability)

6. 6 SD – RF Payload

7. 7 Payload System Integration Option 1 - Each of the two PL systems shall be provided as entirely included within a structural box, to be linked to the nacelle mainframe CGS requires: Definition of mechanical I/F to the mainframe Definition of thermal requirements and characteristics of the box as a whole Option 2 - The elements of each PL system shall be mechanically connected one by one to the nacelle mainframe CGS requires: Definition of mechanical I/F to the mainframe for each element Definition of thermal requirements and characteristics of each element

8. 8 Thermal Design – Environmental conditions during flight mission Each closed volume of the PL subsystem shall be provided by an appropriate venting hole, compliant with the profile of pressure differential over ascent and descent time (TBD)

9. 9 Thermal Design - Process 1.According to preliminary design of the Aerial System, which means definition of the flight envelope, CGS shall provide nominal curves for the environmental parameters over the flight mission 2.PL integrators shall provide thermal characteristics of their systems (intended either as a whole, in case of a single integrated box for each PL, or as subsystems boxes): Operative temperature range Stand-by temperature range Thermal dissipation plan over the flight mission time 3.PL integrators shall check the correct functioning of their systems within the mentioned environment. In case of incompliance of the PL system with the environmental profile, PL integrators shall give a feedback to CGS in terms of maximal ranges and differentials of the mentioned parameters for the correct PL system operation 4.CGS, shall provide solutions for the passive thermal control system 5.Interaction for reaching the mission feasibility, and final design

10. 10 Electrical Power System Electrical power will be managed by two separate systems: EPS for the Upper Aerial Carrier (not affecting the experiment) EPS for PL survival and operation (completely designed out of PL systems requirements) The one I/F between the two systems is represented by the triple connection at standard RS422, for data communication between the PL systems and the TM/TC system onboard the Upper Aerial Carrier. EPS for PL will consist in modular battery packs and harness for power distribution. Two main options for the configuration: Option 1 – Common power bus (common voltage and fluctuation tolerance, according to standards) Option 2 – Dedicated Power Busses, even different for RF PL and OPT PL Both options mentioned above require PL systems to work with Direct Current power supply

11. 11 EPS – System Definition EPS configuration impacts the overall Nacelle design due to: Weight Thermal matters Information required for each of the two PL systems, for EPS preliminary design: Voltage of the system as a whole (nominal and margins for the closed circuit) Max peak power of the system as a whole (value and elongation) Typical power need plan over the entire mission duration Information required for each of the two PL systems, for EPS detailed design: Voltage at the connection PL-Bus (nominal and margins for the closed circuit, fluctuation and ripple tolerance) Need for voltage monitoring and/or stabilisation

12. 12 EPS – Batteries for High-Altitude Applications 1/3 Non-rechargeable Lithium-thionyl chloride (Li-SOCl 2 ) High power (drain and pulse) Wide temperature operative range (-60°C/+85°C) High sealing capability for pressure differential

13. 13 EPS – Batteries for High-Altitude Applications 2/3

14. 14 EPS – Batteries for High-Altitude Applications 3/3

15. 15 EPS – Demo Figure Requirements from multi-PL system: Common Bus, ~28V DC Continuous power drain: 500W  17,36A Operative time: 6h  107Ah Provided packed system Nominal voltage: 28,8V Performances safety factor: >1 @ -40°C, >1,9 @ 20°C Dimensions: 7 packs, each 70 x 70 x 140 mm Weight: 7 packs, each 850g (excluding muntage&protection) Voltage29,36@20°COpen circuit 27,20@20°C19,6A max.cont. 23,04@-40°C19,6A max.cont. Discharge profile11,5h@20°C19,6A max.cont. 6,16h@-40°C19,6A max.cont. Capacity543,2Ah@20°C19,6A max.cont. 291,2Ah@-40°C19,6A max.cont.

16. 16 Deadlines and Actions Volume allocation and geometry constraints within nacelleCGS26/11/04 General thermal Reqs from PLsDLR/UOY31/12/04 Definition Stratospheric Carrier flight envelopeCGS31/12/04 Definition mech. I/F PL-NacelleDLR/UOY28/02/05 Definition Power/Thermal mission plan for PLDLR/UOY28/02/05 System thermal design CGS31/03/05 EPS designCGS31/03/05