ESA Document - Emits - ESA

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2.7.5.1 Mission elements dry masses
Mission Element Mass (tonnes)
THM 55.4 (dry)
MEV 29 (wet)
ERC 10.2 (wet)
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 47 of 422
Table 2-7: Mission Elements masses
These figures are derived mainly from literature or from preliminary simplified computations,
and just represent a starting point.
2.7.5.2 Life support system for the THM
The levels of closure assumed for the life support system are the following:
Element Level of closure (%)
Oxygen 95
Potable water 95
Grey water (condensate, used hygiene water) 95
Yellow water (water in contact with urine) 95
Black water (water in contact with faeces) 20
Solid organic waste to food 20
Solid inorganic waste 0
Packaging reuse 0
Table 2-8: Life support system level of closure
Taking these levels of closure into account and typical mission duration of 950 days, the
consumables required for a crew of six for the whole mission are 10.2 tonnes.
2.7.5.3 Propulsion system
A modular design for the propulsion module has been assumed, that is, separate propulsion
systems are used for each main propulsive manoeuvre. This approach allows the jettisoning of
each propulsion module after its usage. Within each main propulsive manoeuvre, a staging
approach is also followed, so that the manoeuvre is split into several stages to increase the
efficiency of the system. This approach allows you to get rid of the stages once they have been
used and also reduces the gravity losses as the time required for each burn is lower. Therefore,
the system is assumed to be as follows:
• TMI module (3 stages)
• MOI module (2 stages)
• TEI module (1 stage)
In general, each propulsion stage will be bigger than the launcher capabilities in terms of mass,
so, each stage will have to be split into submodules, called stacks. With this approach it is
expected to reduce the cost of the system, as the same design will be used for all the stacks.
Regarding the propulsion technologies used, the values assumed are as shown in Table 2-9: