ESA Document - Emits - ESA

s
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 92 of 422
• No failures assumed.
• As a result of boil-off a refueling flight could be made but is not considered a
baseline. Boil-off is considerable, but acceptable in terms of loss of performance if
kept below 70 kg/month of liquid hydrogen
• No reboosting of composite is included.
The following parameters in Table 2-33 have been used in the model given the assumptions
above:
2) Launch Vehicles, Operations & Production Assumptions
Launch Vehicles
Assumption: Launch window independent between vehicles
Number Name
Nr launches
/year
Launch rate
Performance to
LEO (kg)
Fairing dim1 (m) Fairing dim2 (m)
1 ENERGIA 12 31 80,000
35 6
2 A5 8 46 20,000
10 4.5
3 Proton 8 46 20,000
4 Soyuz 12 31 8,000
5 Shuttle 4 92
Operations
Composite Operations time (non-manned modules) 30 days After Berthing
Composite Operations time (manned modules) 90 days After dock & assembly
LEOP 2 days
Commissioning Duration 8 days Should be about 30 days for launch of the first element in order to check the Ground Segment
On-orbit assembly 3 days
Production Assumption
Development/Integration 8 years/element
Element Availability rate 30 days I.e. time btw one element finished with respect to the previous one
Margin & Commissioning
Assembly margin for each element 0 days
Overall assembly margin 180 days
Commissioning duration 60 days
Commissioning duration/Crew Training 30 days
2.8.2 Sensitivity analysis
Table 2-33: Assembly parameters
Apart from the following baseline analysis, the effect of certain parameters on the resulting
assembly time and total boil-off have been examined.
1. Effect of Energia launch on assembly time
Assemly time (years)
10
9
8
7
6
5
4
3
2
1
0
Assembly time and boil-off
4 6 8 10 12
Energia Launch Rate (launches/year)
140000
120000
100000
80000
60000
40000
20000
0
Boil-off (kg)
Assembly time
Boil-off (300 kg/month)
Boil-off (100 kg/month)
Boil-off (34 kg/month)
Figure 2-47: Assembly time and boil-off as a function of launch rate