ESA Document - Emits - ESA

s
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 90 of 422
• LEO is the preferred assembly orbit. An altitude of 400 km (similar to that of the
ISS) has been selected.
Figure 2-46 shows that the assembly activities potentially establish more than 50% of the total
‘life’ of (some of) the hardware for a given mission timeline. Thus the assembly sequence and
the time spent assembling the composite becomes an important component of the mission
timeline.
Figure 2-46: Mission timeline
• To estimate the composite in-orbit assembly time, the following parameters are
critical:
• Launcher type and frequency of launch
• Element availability rate (on-ground production assumption)
• EVA or Automated assembly
• Cargo or ‘Manned launch’ or Resupply
• Equipment Check-out Times
• Launch failure assumptions
The following assumptions have been made for the In-orbit assembly analysis:
Cargo Launcher = Energia
Launch Frequency
o Min: every 3 months
o Max: every month
Assumptions Qualifying statement
LEO Workbench/platforms present to support LEO
operations & power requirements
(LEO crew Habitat.)
Equipment Check-out times
o Habitation modules 3 months
o Propulsion modules 1 month
Minimise number of manned flights
o Crew support using short term shuttle visits
(Minimise the use of ‘flight systems’)
Minimise Cryogenic Fuel Boil-off
Minimal reconfiguration of vehicle in-orbit after
initial capture & berthing or docking operations
Time
Launcher production infrastructure in place to be able to
launch 1 per month
Operational support
o Up to eight teams working in parallel at ESOC- 1 for
orbital vehicle, 1 each for launcher/mission in prep
LEO workbench provides power, docking & resupply,
AOCS and boost, autonomous Robotic Arm to support
the composite and facilitate Capture & Berthing
operations
Table 2-32: Assumptions for assembly