Page 21 - test

Ref : CM-DFH4-2014-1
BEAZLEY Issue : 1

DFH 4 Series Spacecraft Date : 28 Sept 2014
Page 19 of 38

CHINASAT 9 Observation Comment /Assessment Cri

 Mass budget,  EPS, mass is 600KG, what is behind this colossal number?
 Propellant budget, no comment  What is the worst case DoD

 Power budget,.  Could they confirm that the battery DOD is limited in the
worst case to 75%
System  Proposed in orbit Temperature for the Battery
budgets  TCR Link budget, no comment  No comment at this stage
 Antenna pointing accuracy, no comment  No comment at this stage

 Reliability, 0.71 end of life, seems optimistic  No comment at this stage
with the TWT redundancy proposed.
 SPF list (page 39), seems incomplete, many  Should be updated ASAP
other SPF can be added.
 Page 42-52. According to the presentation most  It is difficult to understand why a unit is Category C with a
of the hardware is qualified, or flight proven. status Flight proven, since the unit is subject to significant
17.2 % of the hardware is in category C (minor changes.
modification like for the antenna which are  There is no mention of life test.
Qualification mission specific) the rest 82.8 % is supposed to  Is the environment for the previous qualification (Vibe,
status be qualified. They state that almost everything thermal, radiations...) encompassing the Chinasat 9 needs.
as the status light proven
 Onboard software qualification, there are many  What is the strategy to spec, develop and test new / modified
items categorized as S3 (flight proven) or S2 software (incremental validation or other techniques)
(modifications)  The FDIR implementation is not presented.
 Page 54.Solar array single junction cell.  Is this “old” technology sufficient to guarantee the power
Platform budget?
overview  Structure subsystem (page 57)  Can this structure survive the ground environment (all lifting
cases, horizontal, vertical). And the ground Tvac
 There is no mention of PFM levels, for design  Surprising for a first spacecraft.
or testing (unit and system level)
 Nothing is said on the predicted temperature  Hopfully there will be more details in the future.
Thermal for each equipment and how they are  What is proposed to avoid the electron charging on the MLI.
control compatible with the one used to qualify each  What is their margin philosophy with respect of In orbit
equipment. What is the in orbit experience prediction ,Acceptance Temperature, qual temperature, flight
Subsystem when using radiative collector. How they will
cool down the satellite during AIT. What is the temperature.
process that they proposed to verify the proper
integration and operation of the Heat Pipe
 Classical subsystem. 14 thrusters in two semi
system  To report on corrective action and implementation on
 Page 67 it apears that they experienced some in spacecraft under development..
orbit anaomalies (helium leakage, 10 N
thruster..)
 The Pyro valves on the LAE are not in
redundancy (the other pyro valves are in  This is a risk item.
redundancy) .In case of a pyro valve failure the
entire mission is lost
UPS  Page 87. For the thusters, There is only one  This is a risk item
latch valve for each branch. If one thruster is
Subsystem leaking, the entire branch need to be isolated,
that means for a single thuster fails, they will
be loosing all thusters in one branch. If they
add latch valve on each 10 N thruster, they can
isolate the defective thruster.

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