Sustainable Satellite Design Activities in the ESTEC CDF - Congrex

Sustainable Satellite Design 

Activities in the ESTEC CDF 

Robin Biesbroek 

SECESA2010 

13/10/2010 

ESA UNCLASSIFIED – For Official Use

Table of Contents 

– Introduction 

– ECOSAT 

– Overview 

– Introduction to C2C and LCA 

– Study logic 

– C2C aspects 

– LCA aspects 

– Trade-offs 

– De-orbiting 

– Overview 

– Aspects using solids 

– Results 

– Other aspects 

– Team behaviour 

– Project behaviour 

– Other CDF aspects (facility, databases) 

– Conclusions and recommendations 

ESA CDF sustainable activities | Robin Biesbroek | SECESA2010 | 13/10/2010 | D/TEC | Slide 2 


Introduction 

– Several activities were launched in the past years within ESA related to 

sustainable development 

– ESA facilities 

– Projects 

– Launchers 

– ESA’s General Studies Programme (GSP) accepted two proposals in this field, 

related to satellite design: 

– ECOSAT 

– De-orbiting 

– Both studies were carried out in ESA’s Concurrent Design Facility (CDF) 

– State-of-the-art facility equipped with a network of computers, 

multimedia devices and software tools, which allows a team of 

experts from several disciplines to apply the concurrent engineering 

method to the design of future space missions 



ECOSAT Overview 

– ECOSAT: a pilot experience in eco-design applied to 

space systems 

– The objectives of this project are related to potential 

and expected lessons learnt worthwhile for any new 

project 

– The challenge has been to include environmental footprint 

assessment at an early stage of the design process and to design a 

mission encompassing technical solutions that allow: 

– Either to decrease the environmental impact (traditional 

engineering / LCA approach) 

– Or, even better, to create a waste free process in which side 

products or waste of a process become input materials for 

another process (C2C approach). 

– Eight CDF design sessions (31 March – 5 May 2009) 



Introduction to C2C and LCA 

– Cradle to Cradle (C2C) is a biomimetic approach to the design of 

systems that seeks to create systems that are not just efficient 

but essentially waste free 

– ‘Garbage = food’ 

– The Sun is the source of energy 

– Respect diversity 

– Life Cycle Analysis (LCA) is a environmental assessment methodology that analyses 

the complete life cycle of a product or a service and translate the associated 

emissions and consumptions into environmental impact evaluations. 


ESA UNCLASSIFIED – For Official Use 

– Based on the fact that all processes of a life cycle (in the supply 

chain, in the use phase, in the end-of-life) cause emissions or 

resource extractions. 

– LCA does not provide a design methodology. 

– LCA is a diagnosis tool which highlights critical environmental 

impacts in the life cycle.

ECOSAT Study Logic 

– Complying with study constraints to not overlap other on-going 

sustainability studies, and focus only on satellite design, it was 

decided that the study team should look into three levels: 

– Level 1: Space mission design. Typical CDF work but putting 

the design emphasis on reducing or obtaining a green 

footprint i.e. reducing space debris, clean propellant etc. 

– Level 2: System engineering. Improve ground-models, 

testing facilities, materials etc. 

– Level 3: Earth-based infrastructure related to space. 

Standards, way of working, facilities etc. 

– The study started with a workshop on C2C given to the team 

– Unfortunately, after following the workshop, the 

methodology behind C2C was still not entirely clear 



ECOSAT C2C aspects 

– After the workshop, a brainstorming session was held on Level 2 & 3 

aspects 

– Number of inputs received by the team……0 

– During the session, in a concurrent way, ideas were formed 

– C2C aspects studied in ECOSAT were: 

1. Certification of used materials 

2. Design for: 



– Disassembly 

– Reuse 

– Recycle 

3. Identify ‘free’ products, services and possible users

1. Certification of used materials 

– Identify used materials 

– Rank them according to, for example, toxicity 

– Apply colour ranking (red = materials to be avoided, green = materials to be 

promoted) 

– CDF has little knowledge on materials used in components 



– Level stops at ‘unit’ level 

– Even elsewhere within ESA, accurate material lists are not well known 

– Known only to suppliers to the satellite contractor company 

– This is their core business → stays secret 

– Exception: propellants 

– Processes have an impact on the eco-footprint 

– Typically >40% of a satellite is aluminium 

– Machined out of massive block that has been forged 

– Impact of forging, thermal treatments, etc. should be taken into account 

– Is it recycled? Only 5% of the energy needed to prdocue metal from bauxite

2a. Design for disassembly 

– Disassembly by de-orbiting (break-up during re-entry) 

– In line with C2C: de-orbiting ‘brings’ the S/C materials back where 

they came from 

– Carbon extracted from CFRP falling on ground can act as 

nutrients for soil 

– Use of origami? 

– Create a shape that increases the chance of total 

disintegration (cracking path) in the atmosphere 

– More suitable for flexible planar structures 



– Problems with fairing size 

– Number of mechanisms

2b. Design for reuse 

– Advocate modular design 

– Reuse units/modules 

– Typical aspect of satellite design in the CDF 

– Indicated by Technology Readiness Level (TRL) 

– But: often when a unit is reused, the TRL drops a few steps 



– A component may have become obsolete 

– A fault in the design was found 

– A way to improve it was found 

– The unit does not fit 100%, small changes required 

– This is common, even in mass-productions 

F355 engine, 1996 version F355 engine, 1998 version

2c. Design for recycle 

– On-orbit servicing? 

– Servicing module characteristics: 

– Will preferably interface with the spacecraft for docking (docking is 

mandatory in case of use of a robotic arm) 

– Shall have solar panels to generate the required power 

– Shall hold a robotic arm (double arm with 7 degrees of freedom in 

each of the 2 arms) 

– Shall hold the Orbital Replacement Units (batteries and electronics) 

– Shall hold the new instruments of the new mission to replace the old 

ones 

– Shall be able to re-fuel the spacecraft for the new mission 

– Will be able to eventually provide a de orbit module to the spacecraft 

– Will eventually use astronauts (Extra Vehicular Activities (EVA)) to 

replace components 

– CDF can play a role as spacecraft would have to be designed for servicing from 

the earliest design phases. 

– But: many constraints/guidelines that become worse in case of servicing by 

astronauts (no sharp edges, rails to hold on to, etc.) 

– May only be viable if many satellites are serviced 



3. Identify ‘free’ products 

– Piggy-back launch opportunities 

– Share of ground antenna use 

– Share of ground equipment use 

– Share of computer capacity on ground-stations 

– Reuse transport containers 

– Typically considered with satellite design 

– Typically done with low-cost satellite design 



ECOSAT C2C aspects: conclusions 

– Unfortunately, the brainstorming did not lead to a clear Level 1 definition 

– Nor to a clear application of the C2C process applied to a space mission 

– An alternative approach was taken: 

– Testing of LCA (Life-Cycle Analysis) software and methodology 

– Trade-offs 

– Launcher 

– Satellite 

– Design of an Earth observation satellite (Investigating the correlation between 

global climate change and thickness of the polar ice gaps) taking into account 

trade-offs including LCA index, with the focus: 

– De-orbit technologies 

– Materials (Solar panels, propellant, structure) 



ECOSAT de-orbiting system trade-off 

– Bad LCA indices were obtained for inflatable & cold-gas propulsion systems (due to high 

mass → large amount of aluminium) and Xenon-based electrical propulsion (due to difficult process to 

obtain Xenon) 

– With the exception of Xenon, any normal CDF system trade-off (minimizing mass, typically) would lead to 

the same result! 

– Level 1 design was done for de-orbiting using mono-propellant (slow re-entry) & solid propulsion 



ECOSAT sub-system trade-offs 

– Material selection for the satellite structure 

– Solar panel material trade-off (GaAs versus Si cells) 

– Reduction of the amount of used ground-stations by using a relay satellite 

– Launcher propellants and green propellants have a high impact on the eco-footprint 

– Improvement of clean-room air-conditioning by better ceilings, new doors 

– Reduction of paper work during Research and Development processes 

– Reduction of amount of travel during projects 

– Office conditions for project team members (air-conditioning) 

– Tele-testing and increased use of virtual models and simulation for spacecraft testing 

– Increasing the amount of satellite autonomy. 

– Again it was concluded that most trade-offs were performed in any satellite design (not 

taking into account environmental issues): 

– satellite structures are often based on CFRP due to its good structure qualities 

(high stiffness at low mass) 

– While a Si cell would receive a better LCA index than a GaAs cell, the LCA trade- 

off would still favour GaAs cells due to their lower mass (the LCA index of the 

entire solar panels system is lower than a Si system) 



De-orbiting study 

– Continuing in the field of de-orbiting 

– Kick-off on the 3rd June 2009 and finishing with an Internal 

Final Presentation on the 16th July 2009 

– The objective was to create an ‘add-on’ package that can 

easily be attached to a spacecraft 

– in line with “design for reuse” 

– The CDF team assessed, more in detail, requirements stated in 

the Code of Conduct for Space Debris Mitigation 

– ESA satellites within certain regions (LEO/MEO/GEO) required to de- 

or re-orbit within 25 years 

– In case the total casualty risk is larger than 10 -4 , uncontrolled re- 

entry is not allowed 

– Solid rocket motors releasing burn products larger than 1mm into 

orbit shall not be used 

– Different options were assessed (same system trade-off, however without LCA 

index) 

– Two baselines were selected. The only baseline allowing for an immediate re- 

entry (i.e. controlled re-entry) was based on solid-propulsion 

– Same option as ECOSAT 



De-orbiting aspects using solids 

– High thrust level of solids 

– The thrust level should be low enough not to rip the satellite apart when ignited 

i.e. causing more space debris! 

– In this study, the acceleration caused by the thrust was limited to 0.04 g, similar 

to g-force limits on geostationary satellites 

– The amount of burn products released in space 

– The Code of Conduct for Space Debris Mitigation requires that solid rocket 

motors releasing burn products larger than 1mm into orbit shall not be used 

– This was solved by selecting aluminium-free propellants. 

– Autonomy 

– Typically satellite operators tend to operate spacecraft until a critical sub-system 

fails, or contact is lost. In this case, a de-orbit sequence won’t be possible unless 

the de-orbiting package can be managed autonomously 

– Even if there is no malfunction, and it’s required to de-orbit, operators try to get 

away with it (apply for ‘waivers’, or continue until propellant runs out) 

– Solid propulsion seems the best solution for implementing an autonomous 

system, as they require only little energy to be ignited (using a small primary 

battery to supply power) and have a short duration thrust 

– One problem remaining is how to achieve the correct attitude of the spacecraft; 

this was investigated at high level but requires further detail 



De-orbiting study results 

– A modular design was proposed 

– Number of motors depending on 

satellite mass & orbit 

– The design has been compared to the option 

of increasing the satellite’s propellant tanks 

(used for other purposes) in order to carry 

enough propellant to de-orbit 

– It was found that in all cases the de-orbiting package was heavier than simply 

adding more propellant 

– This would imply that satellite designs would typically use the latter option i.e. 

adding more propellant. 

– Still, the de-orbiting package offers some advantages: 

– it offers a simple design (‘add-on package’) minimizing impact on 

programmatics and cost, and allowing for a smaller on-board 

propulsion system (used for attitude control, for example) 

– Furthermore the system could be attached to a launcher’s upperstage 

in order to de-orbit it. 

– In CDF studies, the Code of Conduct for Space Debris Mitigation is always 

followed 



Team behaviour 

– The subject of sustainability motivated the team 

– Made ‘aware’ of the situation 

– Team members continued in this trend (e.g. videoconferencing) 

– However, the team found it difficult to understand the C2C methodology 

– Except for material selection; but typically CDF team members do not 

have that knowledge (stays with supplier) 

– LCA approach however was easily adapted 

– More in line with engineering activities 

– Need to think ‘out of the box’, which is difficult for many 

– C2C expert: ‘Use Ariane 5 main stage as ocean reef after splash-down, by 

applying special coatings’; a simple idea that no-one thought of 

– C2C expert: ‘Space exploration is good because it allows human to live on 

other planets’; an idea that is a maybe bit too much out of the box.. 

– A group of C2C experts should be integrated into the team for thoughts 

beyond current procedures & standards 



– Like how James Cameron is on the NASA Advisory Council board

Project behaviour and other CDF aspects 

– When contacting a project manager asking permission to investigate how we 

could improve the eco-footprint of his project, the answer was LEAVE US 

ALONE! 

– This answer is logical: it is seen as an extra constraint 

– After years of optimizing the project to 

cost/risk/mass/programmatics/etc. 

– Management should be convinced that: 

– This is not posing extra constraints 

– This actually reduces cost/risk/programmatics/mass 

– Non-toxic fuel; reduces safety regulations, time schedule and 

therefore cost 

– Replace many project travels by videoconferencing, saving 

almost 1 k€ per travel 

– CDF is a good place to start as project designs start in the CDF 

– The CDF has a fantastic videoconferencing system; used by other 

projects as well; saving ±4 travels per week 

– Large room air-conditioning still difficult (air quality, cold�warm) 

– Install plants 

– Databases (for LCA input) missing → LCA results used with caution 



Conclusions and recommendations 

– The CDF team welcomed the first studies on sustainable design 

– High (and lasting) motivation 

– Difficult to implement C2C thinking 



– A mixed team is recommended (non-engineers etc.) 

– Talk to companies that have successfully implemented C2C 

– C2C would normally not be applied to satellite design 

– Need to think bigger: entire programme 

– Often, CDF designs already focus, indirectly, on sustainable designs 

– Mass reduction 

– Reuse 

– Identification of free products (sharing costs) 

– LCA tool was easy to use (system trade-offs performed) 

– Improvement of databases w.r.t. space qualified components 

– The CDF allows early implementation of sustainable design within project 

– Material & propellant selection, de-orbiting, programmatics etc.

Sustainable Satellite Design Activities in the ESTEC CDF - Congrex

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