ESA Document - Emits - ESA

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2.7.15 Sensitivity analysis
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 87 of 422
A sensitivity analysis on several of the mission parameters was performed during the trade-offs.
The exercise has been repeated over the final design for the study case, confirming the same
trends.
2.7.15.1 Influence of the mass of the THM
Mass to LEO (Tonnes)
Influence of THM mass
2200
2000
1800
1600
1400
1200
1000
30 40 50 60 70 80 90 100
THM mass (Tonnes)
Figure 2-43: Influence of the THM mass
The THM is one of the mission elements that is carried along all the mission phases, so,
propellant has to be provided to give it the required ∆Vs for all the main propulsive manoeuvres.
The dry mass has a huge influence on the overall mass to LEO. Its mass has to be therefore kept
as low as possible.
2.7.15.2 Influence of the closure level in the ECLSS system
Table 2-31 shows an overview of the sensitivity analysis performed concerning ECLSS. The
maximum level of closure signifies 95% O2, 95% water (all but black), 20% black water and
organic waste and 0% inorganic waste.
0% level
of closure
Maximum level of
closure
ECLSS System hardware mass (kg) 7620 9670
Storage hardware mass (kg) 39888 8434
Mass of consumables (kg) 53663 8826
Mass of packaging (kg) 1146 1393
Total mass (kg) 102317 28323
ECLSS system power (W) 3757 4033
Storage system power (W) 3470 3054
Total power (W) 7227 7087
Table 2-31: Influence of the level of closure in the ECLSS for a 1000-day mission