Consert W.Kofman, A. Herique, JP. Goutail, A. Roux

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Consert W.Kofman, A. Herique, JP. Goutail, A.
Roux
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PC8 activities

• A large set of CONSERT test were performed during
  PC8
• Theses operations are essential for CONSERT comet
  operation preparation.
• RF link, Absolute Time Tag commands, OCN
  Interferences test and Long Ping Pong.
• The FOP has been totally rewritten during PC8
  preparation and the validation of the new FOP
  (comet-ready) has been done during PC8.
• The CSA (CONSERT Synchronization Accuracy) has
  been implemented and was validated during PC8

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(No Transcript)
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PC8 results
Figure 1 Consert power versus S/P position from
-50/50 to 70/70 by 5 steps and power measured
during the different PC tests.
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PC8 results

• CONSERT performances are nominal for OCN and
  LCN the instrument works well.
• There is no unexpected TM-losses on the orbiter
  side some minor modifications in the Fop have
  been done in order to avoid some ACK losses
  before time update.
• On the Lander, there are a few losses during long
  ping-pong test using mass memory.
• These limited losses are acceptable and Consert
  can be operated without inconveniences.
• Nevertheless, it is important for us to
  understand and to secure this problem. (CDMS ?)

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PC8 results

• Absolute Time Tag commands (necessary for CONSERT
  cometary operations)
• and RF link tests.
• The Lander synchronization was fine during all
  the operation including Time Tagged commands and
  RF link.
• The Orbiter operation shows a delay of 23
  seconds. This delay seems stable and may be
  attributed to the OBCP management. Further
  investigations or tests have to secure this
  point.

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PC8 results FOP tests

• All the tested sequences are fine. Minor
  modifications have to be done in order to take
  into account the timing of nested sequences.
• Some TC's have to be delayed (minimum 1 minute
  after OCN on) in order to avoid ACK without
  unvalid time stamp.
• User Manuel has to be updated in order to include
  a description of the typical data set for the new
  FOP.

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PC8 results 10h duration ping-pong

• There is no drift observed between the Rosetta
  USO and OCN USO with an accuracy of 10 ms over 10
  hours. Considering the Rosetta USO as a perfect
  reference at this scale, the OCN USO is 10 MHz
  with an accuracy of 3 10-7.
• There is no aging detected on the OCN USO. This
  is significantly better than the aging expected
  from the manufacturer specifications.
• There is no aging on the LCN USO. The LCN USO can
  be used as a 10 MHz reference with accuracy
  better than 10-6.

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PC8 conclusions

• PC8 is successful for Consert
• - Our instrument is operational and the
  performances are nominal.
• - There are limited TM losses between LCN and
  CDMS.
• - The new FOP is operational, some minor
  correction are required in the timing.
• - CSA is an operational parameter of the greatest
  interest in order to secure / validate Consert
  operations.
• - Interference test has provided data of interest
  closing some doors and opening a lot of other
  doors
• - The estimation of the OCXO aging is good

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PC9 results

• PC9 execution start of February 09
• OK
• Consert works well
• no problem detected during this test
• signal shape, noise level coherent

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Interference testsGeneral. Several instruments
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Interferences Miro

• Inconclusive. In fact on average the perturbation
  is negligible however there are sometimes short
  burst of perturbations (lines) increasing the
  noise level of 2-4 dBs. It is necessary to
  understand the reason of these bursts generated
  by MR.

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Interferences VIRTIS and ?

• SCI data altered, noise level higher of about
  5dB during the whole test.
• Line at 88.1 Mhz.

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Interferences (Group 1 in Susceptible Mode)

• Data altered by a high noise level of about 4 dB
• Strong line at 92.12 MHz disappearing for 4
  minutes starting at 13h49 accounting for 2 dB.
• Which instrument generates this line?

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PC10

• Basic tests (performed during each passive and
  active PC)
• Unit functional test O and L
• ping pong test with umbilical and orbiter
  schedulling
• Classical tests (each active PC)
• Orbider schedulling with RF link
• Abslute time tagged command (Lander schedulling)
• Long ping pong test in  comet conditions  (30 h
  2h) , need to check data storage capacity,
  different sampling, etc
• test specific for PC10
• Interference test lander
• Inerference testorbiter (delta PC8)
• Delta fop commissionning
• Test of the turn on synchroization accuracy
  requierement
• Unexpeced 2s propagation delay on OBCP (TB
  nvestigated)

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ATTC Description

• ATTC Absolute Time-Tagged Command
• OCN is scheduled by the Orbiter
• LCN is Scheduled by the Lander
• No other synchronization than absolute time of
  operation.
• Objective
• To test the operational links necessary to modify
  absolute timing of both spacecrafts in real time.
• During PC10
• Modification issued by CN Team short (?) time
  before execution.
• Test of the RMOC LCC SONC part
• During Lutetia Flyby
• Modification issued by real time orbital update.
• Test including the FDy part.