The SSDW 2005 was different from earlier workshops in the way that it was organised as a semester-integrated workshop. This means the students had a timeframe of about three weeks for the design development, simulation, and evaluation. This new concept was supported by a lecture series on Astronautics and Space Station Design.
Considering the current roadmaps of the major space-faring nations and following the evolution of the SSDW software the task for this workshop went beyond low Earth orbit: the students had to develop a so-called Geostationary Servicing Workshop (GSW) as a European-Russian lead international venture, starting operation no later than 2014 and serving as precursor for a later station project in the Lunar Libration Point 1. The GSW should primarily demonstrate safe transportation and system development capability using the envisioned infrastructure elements, but it should also enable servicing missions to satellites in GEO as well as research activities in the high Earth orbit environment (phase I). In particular, the station concept should:

1. be a cost-effective minimum configuration
2. support human-tended operation with crewed missions twice per year
3. foresee an international crew of three astronauts
4. be adapted to extended crewed periods for long-duration and isolation studies, starting around 2016 (phase II)

The students used a modified SSDW methodology, and SSDW tools like COMET, IRIS++ and ELISSA, to design and analyze their stations.

Here is some data on the space station concepts that the two design teams proposed. More detailed information on the workshop and its results can be found in the Final Report (PDF, ca. 5 MBytes).

Blue Team

System Concept:

• Crew: 3
• Orbit: geostationary +/- 300 km, circular, 0° inclination
• Flight mode: earth-oriented
• Mass in orbit: 60.249 t (phase I), 92.850 t (phase II)
• Installed electrical power: 58.4 kW
• Vehicles:
  • transport: Automatic Transfer Vehicle Logistic (ATV-L), Automatic Transfer Vehicle Heavy Duty (ATV-HD) and External Tank Module (ETM)
  • crew transfer: Soyuz-based Crew Rescue Vehicle (CRV)
  • logistics: Progress-based Lunar Transfer Vehicle (LTV)

Space Segment Description:

ECLSS Design and Simulation:

In phase I Team Blue anticipated a semi-closed life support system with air revitalisation and waste water recycling. It is designed to support three astronauts for at least 100 days. Major ECLSS components:

• Water loop: Vapor Phase Catalytic Ammonia Removal Unit (VPCAR)
• Air loop: Four-Bed Molecular Sieves (4BMS), Electrolysis; Trace Contaminant Control System (TCCS), Sabatier

In phase II the system is further closed by inclusion of biological components for long-term studies. These additions are.

• an algae Photo-Bio-Reactor (PBR) for air-revitalisation and food production
• a Salad Machine as a plant growth facility, also for food production
• an Air Evaporation System (AES) for additional water treatment

Green Team

System Concept:

• Crew: 3 (6 for short periods in phase II)
• Orbit: geostationary between 35783 - 35803 km, 0° inclination
• Flight mode: sun-oriented (inertial)
• Mass in orbit: 52.870 t (phase I), 77.930 t (phase II)
• Installed electrical power: 49.47 kW
• Vehicles:
  • transport: Automatic Transfer Vehicle Logistic (ATV-L), Automatic Transfer Vehicle Heavy Duty (ATV-HD) and External Tank Module (ETM)
  • crew transfer: Soyuz-based Crew Rescue Vehicle (CRV)
  • logistics: Progress-based Lunar Transfer Vehicle (LTV)

Space Segment Description:

In phase I the station consist of:

• Command and Satellite Service module (COM, Zvezda-derived)
• Habitation and Laboratory module (LAB, Zvezda-derived)
• Cupola for observation
• European Servicing Satellite (ESSAT)

In phase II the configuration is completed by adding:

• Long Duration Module (LDM)
• Advanced European Robotic Arm (A-ERA)

This LDM provides additional research facilities as well as an exposed platform.
The ECLSS is a semi-closed system in phase I, enhanced with biological components for further closure in phase II.

AOCS Design and Simulation:

Due to the positioning of the station in geostationary orbit the forces and torques acting as disturbances are rather small compared to LEO and the solar pressure becomes more relevant. Taking these favourable conditions into account, the station showed excellent attitude performance since the small torques can be easily compensated.
The station uses gyros for accumulation of angular momentum and thruster systems for periodical desaturation manoeuvres (about every 25 days). The figure below shows the simulation carried out using the IRIS++ software for the inertially oriented station of Team Green.


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