Research, Development and Innovation Programme – Space Technology Advanced Research

3.11.1. ADCOSSPA

Results Presentation

Phase I (19.11.2012-14.12.2012)

Phase Objective

The first phase of the project, “Establishing general requirements and design - I”, is, as the title suggests, outlining the general prerequisites for the microsatellite electrical housing. Phase I comprises:

Activity 1.1 “Establishing requirements. Part I”

„Management si dissemination”

Activity 1.1 targets establishing a preliminary set of requirements for the microsatellite electrical housing, based on data gathered from literature and on the consortium team member’s own expertise, and include a brief introduction regarding the manufacturing of the microsatellite electrical housing from composite material in a national and international context.
The “Management and dissemination” activity is intended to set-up the project’s “Kick-off Meeting” and to hand-in the first iteration of ADCOSSPA’s website structure.

Scheduled Results for Phase I

Establishing general requirements that the microsatellite electrical housing performed in composite materials within the ADCOSSPA project, must meet.
The organization of the ADCOSSPA project: Kick-off Meeting (No.1./ November 28th 2012). Establishing the structure for the ADCOSSPA project website.

Phase I Results

The objectives of Phase I “Establishing general requirements and design - I” have been reached. A preliminary set of requirements for the microsatellite electrical housing, developed by the ADCOSSPA project, have been established within Activity 1.1. This data will be the basis for the proceeding of the second phase, “Establishing general requirements and design - II” (which includes both the final requirements for the microsatellite electrical housing and analysis of documentation for the structure – the CAD model). Within phase I’s “Management and dissemination” activity the following have been achieved: the launch gathering for the ADCOSSPA project “Kick-off Meeting”(including work agenda, the minute of meeting, list signed by the participants).The Kick-off Meeting was held at the project coordinator’s headquarters (INCDT COMOTI), in order launch the project officially, after the contract signature (nr.9/19.11.2012). During the meeting the ADCOSSPA project objectives and the expected results were presented. Likewise, a round table with the project consortium members took place. This allowed the introduction of the members the project: Project Director, Project Responsible from Partner 1 and research teams of both partners: Coordinator: INCDT COMOTI and Partner 1: ICPE-CA but also, provided the opportunity to discuss the role of each team member within the project. An overview of the management organization including project reporting, meetings, risks assessment, rules regarding confidentiality, publication of information, intellectual property, dissemination and financial aspects was presented by the project director Dr. Raluca Voicu (INCDT COMOTI) and assisted by the project responsible from Partner 1 Dr. Adela Bara (ICPE-CA). Another important session was dedicated to the ADCOSSPA project work plan including the structure, the objectives, the inputs and outputs as well as the internal deliverables, milestones and contracting authority phase Reports. Within this session of the meeting, the discussions were focused on the Work plan with respect to Phase I : Etapa I –“General requirements and design definition-part I”: Activity 1.1: Requirements definition Part I and Management and dissemination (Delivery date /report 14.12.2012). At the end of the Kick of Meeting, discussions with the research teams of both partners took place setting the conclusions of the event and the future activities in the ADCOSSPA project. A first iteration regarding the project web page was set.

Phase II: "Establish general requirements and design - II" (14. 12. 2012-20. 04. 2013)

Objectives: The objectives of the second phase of the project "Establishing general requirements and design - II" are: to establish final general requirements for electronics box that houses the electronic of a microsatellite and providing a first iteration on the design solutions for the composite satellite electronic housing. Phase II includes the following activities:
Activity II.1. “Requirements definition Part II”
Activity II.2. “Study on the design of the satellite electronic housing mechanical structure: CAD models”
Activity II.3. “Management and dissemination”

Summary of Phase II: In order to determine the materials structural design for the box that houses the electronics in a microsatellite, is necessary to know: operating conditions and establish/define clear requirements of which the mechanical structure of the composite electronic housing must answer, and structure design for electronics satellite housing: CAD model. Activity II.1., aimed to establish a final set of general requirements for the box that houses the electronics in a microsatellite based on: existing standards for such space structures, data from the literature and own expertise. This activity includes a brief introduction on the national and international situation on the manufacturing of the electronic microsatellite housing, from composite materials. Activity II.2. aimed performing a study on the mechanical structure design of the box that houses the electronics in a microsatellite, resulting in providing at least three different CAD models for it. During this phase it was also performed a first iteration of stress analysis in static regime on CAD version 1 (in aluminum). Stress calculations will be continued and based on these results, the configuration and the optimal design (CAD) for electronic microsatellite housing structure will be established (in the third phase “Structural design and analysis"). Within the activity „Management and dissemination” three „periordic technical meetings” were organized (meeting no 2, 3 and respectivelly 4), both at the coordinator and Partner 1 headquarters, during which technical and scientific aspects related to the second phase activities were under discussion. Also in this activity has been updated the ADCOSSPA project webpage (in Romanian and English versions) with the results of Phase I, in order to inform, disseminate project results.
Scheduled Results for Phase II:

Establishing the final general requirements that the microsatellite electrical housing made in advanced composite materials within the ADCOSSPA project, must meet (Deliverable no. D1.1.1. "Final Report: Requirements definition").
Perform a literature survey and provide a documentation study on the microsatellite electronic housing mechanical structure design, resulting in the definition of at least three different CAD model solutions for the electronics box that houses a microsatellite. (Deliverable no. D1.2. "Study: CAD models").
Organize and perform technical periodic meetings at both the coordinator and Partner 1 headquarters within Phase II of the ADCOSSPA project (meetings no 2, 3 and 4), in order to discuss technical and scientific aspects related to the phase activities. Update of the project webpage.

RESULTS:

Activity II.1. “Requirements definition Part II”
Low altitude orbit LEO (Low-Earth Orbit LEO), is the one of interest for the present study, the majority of satellites operates at these altitudes between 150 and 2000 km above the earth's surface. The space environment (LEO orbit) is characterized by: very low pressure (advanced vacuum), extreme temperatures (depending on the orientation of the material towards the sun, thermal cycles), electromagnetic radiation, exposure to various atomic species and loaded particle (in various concentrations depending on altitude and solar activity), the impact with micrometeorites and fragments of space (space debris).
In LEO space environment (which can be experimentally simulated)
• ultra-advanced vacuum (~ 10-6 Torr)
• UV radiations (<200 nm)
• Thermal Cycles (-70 º C to + 100 º C)
• Exposure to oxygen atoms (AO-flow = 4.5x10-16 atoms/cm2s)

Research, Development and Innovation Programme – Space Technology Advanced Research – STAR

Simplified model of the cover plate (wall) of the microsatellite electronic housing, subject to many constraints in LEO environment. Final Requirements matrix for the composite box that hosts electronics in microsatellite, developed within the project ADCOSSPA.

Property	Requirements
Mass	Minimized *
Dimensions	Fixed **
Access	Comparable to Aluminium box reference [3,4]
First fundamental frequency	>150Hz
Random vibration	Max 15g RMS (qualification level)
Strength	+ MoS At least Equal to Aluminium box reference
Thermal performance	Equal to Aluminium box reference
Radiation shielding	Equal to Aluminium box reference (LEO- Low Earth Orbit regime, altitudine < 2 000 km)
Grounding	<5 mOhm
EMC	Equal to Aluminium box reference
Costs	Minimized

* ADCOSSPA project targets a minimum weight reduction of 30% compared with aluminum reference.
** size and dimensions will be consistent in terms of tolerances to those of the reference aluminum: 460 mm x 154 mm 250 mm.

The next step after setting the final requirements for the composite structure that houses the electronics in a microsatellite is to define design and geometry. Generating an optimal design methodology for composite structure box (space housing type) and its application to optimize weight are important. The proposed design methodology should include constraints on radiation attenuation, natural frequency of vibration, structural integrity, electrical resistivity and also to limit distortions of shape generated by thermal load (heat cycles).

Activity II.2. “Study on the design of the satellite electronic housing mechanical structure: CAD models”

Within the Phase II of the ADCOSSPA project, activity II.2., three versions of CAD models were developed (Figure 2) for the box that houses the electronics in a microsatellite, having as reference the model ADPMS "Data and Power Management" from Proba 2 microsatellite. For the three design solutions, CADs rivets, such Tripo - mushroom head, as represented in Figure 1, were used for assembly that can be in aluminum, steel, copper. For the version 1 and 2 of CAD were used rivets 4.2 mm in diameter and for the third version rivets of 3.2 mm diameter bolts (figure 1).

A first iteration of stress analysis was performed, in static regime, at loading of 6g on Ox, Oy and 11g on Oz, on the box structure (aluminum) without assembly with rivets (figure 3).

It can be seen that maximum effort is 4.76 MPa at a load of 6g on Ox, Oy and 11g on Oz. Safety factor is 57.9, exceeding the value of the safety coefficient of 1.2 commonly accepted for space structures. Stress Calculations will continue with:
- an iteration of stress calculation in static regime, at a load of 6g on Ox,Oy and 11g on Oz, on the box structure
- an iteration of stress calculation in static regime at a load of 6g on Ox,Oy and 11g on Oz, on the box structure taking in account both ribs, attached with rivets, studs, and weight (electronic boards, connectors).
- Iterations of stress calculation in dynamic regime. Calculations will be carried out in two steps separating the launch phase and the in orbit operation regime. Thermal and radiation calculations will be integrated by establishing two final working configurations (CAD's).

5. CONCLUSIONS:

The objectives of Phase II: "Establish general requirements and design - II” have been achieved. Within the Activity II.1. “Requirements definition Part II”, was established a set of final requirements for the box that houses the electronics in a microsatellite, developed within the ADCOSSPA project from composite materials (Deliverable no. D1.1.1. "Final Report: Requirements definition"). Within the Activity II.2. “Study on the design of the satellite electronic housing mechanical structure: CAD models”, a documentation study regarding the mechanical structure design on the box that houses the electronics in a microsatellite was performed, resulting in the establishment of three solutions of CAD models for the box that houses the electronics a microsatellite (Deliverable no. D1.2. "Study: CAD models"). These results obtained in Phase II will be the basis for third phase activities " Structural design and analysis" in which: the optimum design(s) (CADs) for composite mechanical structure of the box will be chosen; numerical simulations FEM on the elements structure / models, will be performed; the test configurations will be selected, composite materials and structural design will be define, the mold design will be defined for the mechanical structure of housing electronics inside the satellite.
Setting a final design and clear requirements at which the mechanical structure of composite box must answer is the basis of the project. Understanding the phenomena’s and the exact parameters at which the mechanical structure is subjected will ensure the optimum running of the project and getting the desired results. Within the activity "Management and Dissemination" were organized and held three regular working meetings, at both the coordinator and the partner P1 headquarters (technical meeting no2, 3 and 4), discussing scientific and technical aspects related to the Phase II activities of ADCOSSPA project. The website of the project ADCOSSPA created in Phase I, was updated with Phase II results and will be updated periodically throughout the duration of the preset project.

Phase III : „Elaborated Study on final space functioning requirements” (21. 04. 2013- 20. 12. 2013)

Objective : assessment and state of the operating/exploitation conditions for space structures and final requirements that the composite electronics housing structure of the microsatellite developed using autoclave technology within the ADCOSSPA project, must meet.

Results : Space structures that are part of the satellite must be stiff, to assure dimensional stability at lunching stage and during on orbit operation. Materials with high thermal conductivity decrease the dimensional distortion issues by isothermalization of the structure from the two own vehicle shadows and from thermal cycling outside the Earth shadows. A low thermal coefficient of expansion decrees likewise the dimensional distortion. Mechanical strength is a critical parameter at lunching stage but once the satellite operates on orbit this become negligible due to low mechanical loading. The main on orbit loadings are thermal ones, generated by thermal cycling and keeping stiffness during on orbit operation (in case vibration induced by rotation, manoeuvres for the satellite). The displacement and natural frequency are proportional to the elasticity module of material(s). Nevertheless, integration of advanced materials in space vehicles is not an easy task, when looking at the critical lunching and functioning requirements. Low altitude orbit LEO (Low-Earth Orbit LEO), is the one of interest for the present study, the majority of satellites operates at these altitudes between 150 and 2000 km above the earth's surface. The space environment (LEO orbit) is characterized by: very low pressure (advanced vacuum: ~10-6 Torr), extreme temperatures (depending on the orientation of the material towards the sun, thermal cycles: [-70 ºC to + 100 ºC]), UV(< 200 nm), gamma and electromagnetic radiation, exposure to various atomic species and loaded particle (in various concentrations depending on altitude and solar activity, i.e. AO-flux = 4.5x10-16 atoms/cm2s), the impact with micrometeorites and fragments of space ("space debris"). Final Requirements matrix for the composite box that hosts electronics in microsatellite, developed within the project ADCOSSPA.

Property	Requirements
Mass	- 30% compared to Al reference structure
Dimensions	Fixed *
Access	Comparable to Aluminium box reference frontal/lateral
First fundamental frequency	>150Hz
Random vibration	Max 15g RMS (qualification level)
Strength	+ MoS At least Equal to Al box reference
Thermal performance	Equal to Al box reference
Radiation shielding	Equal to Al box reference (LEO- Low Earth Orbit, altitudine < 2 000 km)
Grounding	<5 mOhm
EMC (conductivitate electro-magnetica)	Equal to Al box reference
Cost	Minimized

* Composite structure dimensions [the ADPMS system design merges two bus units into one, where the DHS (Data Handling System) + PCS (Power Conditioning System) = ADPMS] must be in agreement with the ones of then aluminium reference: 460 mm x 154 mm 250 mm.

Conclusions : Phase III objectives were achieved, establishing operating conditions for spatial structures and bringing the contributions to establish final requirements that electronics housing for the microsatellite, made of composite materials in the project ADCOSSPA must respond.

Phase IV - STAR ctr.9/2012

Title (Phase IV ): « Structural Design and analysis. Composite Materials R&D »

Period: 21/ 12/ 2013- 20/ 11/ 2014

Phase IV Activities:

• IV.1 CAD design of structural elements/models

• IV.2. FEM simulation on structural elements/models

• IV.3. Selection of the test configurations: material and structure design

• IV.4. Design of the mold for the satellite electronic housing mechanical structure

• IV.5. Creating and customizing the structural materials

• IV.6. Laboratory testing of the proposed materials for structural and mechanical characterization

• IV.7. Drafting of the preliminary manufacturing process

• Management and dissemination

Results:

1.1. CAD design of structural elements/models

3 geometrical designs were developed: CAD I,II and respectively III, with dimensions fixed at: 460 mm x 154 mm x 250 mm. Based on preliminary FEA results a down-selection process was performed based on criterion: weight, accessibility-integration of electronic units and required high mechanical performances mainly in dynamic regime (critical for launching stage), following optimization operations (geometrical) and structural for the CAD -II selected solution. The Final design configuration integrated within its main structure: 3 composite components (laminate type) from CF(₁,₂)RP material: frontal, "L" and "U" shape components, but also metallic elements in aluminium (AA 6068): 2 lateral ribs, stiffeners (for integration and stiffness), one frontal frame (for closing structural assembly and stiffness) and respectively 2 railway plates for the electronic units integration (of the microsatellite). The composite components assembly with the metallic items was performed using aluminium tribo blinde rivets of 3.2 mm diameter (ussualy used in space applications).

1.2. FEM simulation on structural elements/models results

Both static and dynamic(vibration) regime finite element analysis were performed. The minimum safety coefficient for the advanced composite structure was calculated using Hashin fabric theory, which was used also within this study for failure mechanisms assessment for the composite material within the space structure. Example: CAD1-CFRP (static analysis results)

Min. Safety factor distribution (at corner region) within the composite components FOS = 8.3

Failure mechanisms of the composite structure at last ply level (external ply under the Ta foil)

For the modal analysis a simple criterion was chosen, that the first natural frequency of the lightweight composite space structure (integrating electronic units of the microsatellite) to be greater than 100Hz, in order to avoid interferences with the launcher vibration frequencies. For the lateral frequencies vibration range a fundamental frequency higher than 50 Hz is accepted, nevertheless, considering that the final mounting position of the developed structure is not set, for structural security raisons, a first natural frequency higher than 100Hz was required. Exemple: CAD2-CFRP (results of modal analysis)

First 3 vibration modes at resonance of the space structure housing (CAD2 design)

The fundamental vibration frequency of the structure's assembly is at 107 Hz, near 100 Hz. Further, based on the finite element analysis results of the three geometric versions integrating the structural concept High Z-Low Z-High Z, was optimized the CAD-II, obtaining the optimized version of the CAD - Final Design, which comprise the stiffening of the structure (CFRP ribs for the CF(₁,₂)RP composite component "L", respectively "U"). The modal analysis results indicated a first vibration frequency of 115 Hz. The nonlinear static analysis indicated a minimum safety factor >5 for all the studied configurations (aluminium reference and composite structure), higher than 2, requirement indicated in ECSS-E-ST-32-10C Rev.1 (2009) standard for polymeric reinforced structures.

1.3. Test configurations: material and structure design

The materials under study for the manufacturing of structural design were :

- CFRP : UD- EP142-CR509-160-35; CC206/CE662; EP 127-C20-45 T2.

- aluminum (6082-T6) for the lateral ribs/stiffeners (left/right, support plate for the electronic boards, the front rib and for the clamps of the box in the satellite).

- tungsten or tantalum: foils of 0.08 thickness, mechanical and chemical treated to obtain a higher roughness and to ensure a strong interface composite-metal, which is integrated in the hybrid structure, in order to increase the γradiation resistance.

A sketch of the selected structural design, Low Z-High Z-Low Z, is shown in the next picture.

The structure's components and the structural design- section view

Low Z-High Z-Low Z-Final Design

Main strctural materials

EP127-C20-45 (Gurit) CF(1,2)RP with cyanate ester thermoset polymeric matrix reinforced with carbon fiber. The material has a density of 1.5 g/cm³, compared to the reference material AA 6058 (2.8 [g/cm³]). In order to ensure the mechanical strength (and stiffness) required for the launching of the microsatellite (mainly in dynamic conditions, vibration), the reinforcement of the matrix was achieved using high strength and high modulus carbon fiber 3k. Mechanical characterization of the material was accomplished through a experimental test campaign in the laboratory, using a mechanical testing machine Instron 8802 from INCDT COMOTI. The next table shows a review of composite material characteristics obtained.

Property	Value (RT)	Standard	Value (120°C)
0° Flexural Strength	910 MPa	ISO 178	840 MPa
0° Flexural Strength	49 GPa	ISO 178	47 GPa
0° Tensile Strength	760 MPa	ISO 527-4	710 MPa
0° Tensile Modulus	59 MPa	ISO 527-4	58 GPa
0° Compressive Strength	800 MPa	EN 2850	710 MPa
0° Compressive Modulus	48 GPa	EN 2850	41 GPa
±45° In-Plane Shear Strength	104 MPa	EN 14129	85 MPa
±45° In-Plane Shear Modulus	G₁₂=4GPa	EN 14129	3.9 GPa
0° Interlaminar Shear Strength	X_ILLS=74 MPa	DMS 2144	64 MPa

Materials used for the developed structural design meet the requirements of ECSS-Q-ST-70-02C and ASTM E595 (developed by NASA) standards concerning the outgassing phenomena for the materials used in space applications. The analysed samples showed a total mass loss (TMP[g cm^-2]) <1% and an amount of collected condensed volatile substances (CVCM) less than 0.1%.

In order to ensure a high value of the thermal conductivity of the heat dissipation released by the electronic units, was used a second type of carbon fiber (λ=1000 [W/mK]) as reinforcing phase of the thermoset matrix (cyanat ester).

Tanatalum foil (thikness of 0.08 mm) symmetrical integrated (embeded) in the composite structure (forming a hybrid structure), in order to increase the ionizing radiation resistance (γ).

The aluminium AA 6082-T6 ribs are used to integrate the space structure in the microsatellite to stiffen the structure and to ensure (ionized) radiations shielding and the thermal transfer in vacuum, required for heat dissipation released by the elecronic units of the microsatellite

The structure was partially validated for the impact: Space debris: impact speed: 10 km/s, impact direction:45° from the normal of impacted surface, impactor density: 2.0 g/cm³. Thermal cycling strength was carried through exposure to 10 cycles of 100 minutes [-100;+100°C], in the climatic chamber, Hrel=0%, but in the absence of advanced vacuum environment (critical condition). After exposure the structure showed no degradation or significat structural changes. The exposure period was limited, thus, the stability and dimensional integrity of the structure wasn't damaged. The thermal conductivity of the structure has not been experimental determined. CTE (coefficient of thermal expansion) of the CFRP basic structure is 0.125x10-6 /K-1, ensuring the necessary dimensional stability, although, a critical issue in the project is the difference between the composite CTE and the metallic inserts CTE (tantalum foil, AA6082-T6 ribs) that can lead to tensions at the interfece during the polymerization process.

Radiation: The level of radiation on low orbit (LEO) at 600 - 900 km altitude: Electrons: 40 [keV] - 5 [MeV], based on AE-8 model; Protons: 100 [keV] - 200 [MeV], based on AP-8 model; X-ray: 0,1 - 10 [keV], according to solar eruptions, from photons with energies of 1-3 [keV]; Photons (Bremsstrahlung): made by radiation deceleration inside the material, contributes to degradation of material coatings; UV: FUV (far ultraviolet): 0,1 [W/m2] or 0,007% of solar electromagnetic radiation; NUV (near ultraviolets): 118 [W/m²] or 8,7% of solar electromagnetic radiation. Neutron bombing: creates collisions that produce punctual defects and material structure deployments. At high energies, they can lead to metallic or nemetallic material brittleness and their expansion, limiting their potential Gamma rays are absorbed by high atomic number and high density materials, but the most important criteria is which determines the material degradation is weight/area rate. Alpha and beta rays are less critical for polymeric materials, because they can be film shielded. Electromagnetic shielding as well as exposure, abrasion due to atomic species and charged particles, especially oxygen atoms, have been studied during this phase.

1.4. CAD Design of the mold for the satellite electronic housing mechanical structure

Exemple: CAD Model mpuld for "L" shape composite component

Mould material: Necuron 701. The selection criteria's: coeficient of thermal expansion CTE, colose to the one of the processed material (CFRP), in order to avoid stress concentrations do to CTE materials mismach, which can aprea during processing; high thermal resistance (polymerization process takes place at 160°C); easy mechanical operations and precision; thermal cycling resitance 9fatigue0; low density (mobility during manufacturing process).

1.5. Customized structural materials Design

Results are integrated in the section 1.3 presentation, above.

1.6. Laboratory testing of the proposed materials for structural and mechanical characterization

30 structural configurations were developed as laminates and samples with thicknesses of 2 mm using autoclave technology and afterwards tested in different regimes. The developed structures were examined before and after exposure to gamma radiations (from 10 to 500 Gy, Ce137 source with 0.4 KGrey/h) to determine the aging effect on the material microstructure and morphology; glass transition temperature (Tg) which sets the maximum temperature of the structure during service ; thermal conductivity (k) ; specific heat (c) ; thermal expansion coefficient (CTE) ; surface properties of the material (adherence, adhesive strength) ; tribological characteristics (friction coefficient/resistance, wear resistance) ; mechanical performances (static regime).

Several type of tests and analysis were performed : mechanical tests (shortly described in section 1.3 above) ; thermogravimetric analysis and dynamic differential calorimetry (TG-DSC) according to SR-EN 11357 : 2000 ; thermal diffusivity analysis, thermal conductivity analysis and specific heat analysis, thermal expansion coefficient analysis where it has been observed that an increase of radiation dose determines a decrease of temperature at which phase transformations in composite takes place, but in the same time the thermal transformation range become wider.

1.7. Preliminary manufacturing process- work protocol

The mould preparation operations were defined: grinding, cleaning, applying gelcoat, planarity and roughness measurement, etc., components (CF(_1,2)RP structures: "L", "U", front plate): dimensions, structural design, structural or assembly elements, ribs positioning (number of plies, dimensions, sequence, etc.); main structural materials: materials (Tantalum foil, CF(_1,2)RP composite, Aluminum ribs). CF(_1,2)RP composite: number of plies, reinforcing thermoset resin volumetric fraction, ply thickenss, fiber orientation, ply dimensions, tantalum foil, mechanical and chemical surface treatment (adherence to the main composite materials structure, aluminum ribs/stiffners, dimensional control after mechanical operations, positioning within the structure, assembly method, etc. Likewise operations and processes: lay-up, vacuum bagging (basic and auxiliary materials) and curing cycle (autoclave technology), were defined.

Management and diseemination

Two technical meetings were organized: No.6/09.05.2014 and No.7/31.07.2014. The webpage of the project ADCOSSPA was updated (accesible on http://www.comoti.ro, in romanian and english) with the most recent results of the project. The ADCOSSPA team participated to the annual conference organized by contracting authority ROSA, "Romanina Space Week", 12-16 May 2014, bucharest, Romania.

Papers and conferences:

- scientific paper "Equipment Design and Structural Analysis of CFRP Electronics Housing vs. Aluminum Electronics Housing for an ADPMS" autori: Sorin Draghici, Florin Baciu, Raluca Voicu, Anton Hadar la conferinta ICSAAM 2013, The 5th International Conference on Structural Analysis of Advanced Materials 23 - 26 September 2013, Island of Kos, Grecia.

- scientific paper "Influence of advanced vacuum and temperature variations on the behavior of subassemblies of a satellite" Sorin Draghici, Florin Baciu, Raluca Voicu, Anton Hadar la conferinta 6th International Conference "Biomaterials, Tissue, Engineering&Medical Devices", 17-20 September 2014, Constanta, Romania

- scientific paper "Modelarea comportamentului la lansare a unui subansamblu din componenta unui satelit" Sorin Draghici, Florin Baciu, Raluca Voicu, Anton Hadar, Academia Oamenilor de Stiinta din Romania, Proceeding Sesiunea stiintifica de Primavara, 9 May 2014

- scientific paper "Structuri din materiale compozite avansate dezvoltate prin tehnologii performante pentru industrii de varf: aeronautica si spatiul la Insitutul Na?ional de Cercetare-Dezvoltare Turbomotoare COMOTI" Stiinta si Tehnica magazine, no.41 November /2014

Conclusions:

The objectives of Phase IV have been achieved. Based on the results from Phase III of the project, after establishing the final specific set of requirements for the space structure which integrates the electronic units in a microsatellite, the structural design and geometry (Final Design) has been defined and the methodology for designing the space composite structure has been created including the constrains for radiation shielding, first natural vibration frequency, structural integrity, electric resistivity and in the same time to limit the shape distortions generated by thermal loads (thermal cycles). Composite and metallic material selection has been performed for the space structure; different types of material configuration were tested, followed by material purchase. Validations of the structural design and of the selected materials for the space structure have been achieved during Phase IV, based on numerical simulations (FEA) and on the results from laboratory tests. Starting from the optimal design (CAD of structure elements), the mould required for the manufacturing process of the composite space structure has been designed. Likewise, during the Phase IV of the project, the preliminary manufacturing protocol for the mechanical compositespace structure hosting the electronics of a microsatellite, has been defined.

Research, Development and Innovation Programme – Space Technology Advanced Research – STAR