00: EndtoEnd Science

1
IBEX Science Working Team Meeting
00 End-to-End Science Analysis Methods
Geoffrey B. Crew
Orbital Sciences CorporationOct 17-18, 2008
2
Outline

• What is this all about?
• Simulation of Reality
• Starting point is some Heliospheric ENA emission
  model
• Trace ENA flux in to 1 AU
• Pass through sensor response
• Observe ENA counts and simulate telemetry
• Simulation of Pipeline Analysis
• Unpack Raw data for an orbit
• Generate DE or HB event lists and other orbit
  products
• Use the sensor response to estimate local
  differential energy flux
• Trace flux back to Heliosphere
• Construct global maps of Helispheric emission
• Compare

3
Preamble Processing Pipeline

• The ISOC has a large set of tools
  (ISOCGNU/Linux)?
• They are assembled into a pipeline to perform the
  core processing tasks

4
So What is this talk about?

• There are many steps to the processing...
• There are many details and choices to make...
• There is no previous global map with which to
  compare...
• (That's both a blessing and a curse.)?
• So this talk is really about proving that the
  pretty pictures we get at the end are believable
• It's also about showing you what is going on
  inside the ISOC
• The software is designed to be expanded,
  improved, played with, and (ultimately) a useful
  analysis tool
• This is very much a work in progress...

5
Assume a Heliosphere...
Kappa Dist. Opher Model
Kappa Dist. Pogorelov Model
Maxwellian, Opher Model

• The starting point is the output of some
  heliospheric model (such as Christina Prested
  described at the last SWT meeting) which
  describes the source differential energy flux of
  ENAs
• Require flux estimates on the full sky across all
  IBEX energies

0.45 keV
1.1 keV
2.6 keV
6
Flux Mapper

• flux_mapper is a tool which ingests the
  heliospheric model
• It has most of the physics we presently know how
  to use
• Charge exchange cross sections
• Radiation pressure
• Solar wind model...
• It has ENA tracing capabilities
• It has representations for both sensors and IBEX
• IBEX-Hi Collimator response (doubles and
  triples)?
• IBEX-Lo Collimator response (doubles and
  triples)?
• Model ephemeris for IBEX and a spin model
  (spinal_tap)?
• It has simulation fidelity flags
• It's a beast. (My daughter says that's a
  complement.)?

7
IBEX-Hi Direct Event Lists

• Simulated IBEX-Hi direct events DE's made by
  flux_mapper are fed to hi_de_test

8
IBEX-Lo Direct Event Lists

• Simulated IBEX-Lo direct events DE's made by
  flux_mapper are fed to lo_de_test

9
Fake Telemetry

• The IBEX-Hi and IBEX-Lo SSR simulations are
  combined with simulated ACS (Attitude Control
  System) quaternion data (spinal_tap) and passed
  to a simulation of the telemetry process. (I'll
  skip the details.)?
• As an aside, quite a few things are missing
• No simulation of the background monitor (yet)?
• Star Sensor simulator exists but isn't presently
  included
• No realistic singles or monitor rates
• No housekeeping whatsoever
• The resulting VCID2 (SSR) file of telemetry
  frames is then acquired via SFTP and
  collected by the raw telemetry ingester (a
  really crude simulator of ops2raw_filer.pl).

10
Raw to Basic Processing

• The raw data for a single orbit (in this case
  simulated orbit 9023) is gathered and processed
  to regenerate the original CCSDS packets stored
  in the SSR
• Useful collections of packets are made for
  further work
• o9023.pkt_sc (s/c housekeeping)?
• o9023.pkt_pl (all p/l telemetry)?
• Several operational tasks are carried out at this
  time (missing SSR blocks, c.)?

Fake telemetry file
Other flux_mapper products
11
Data Product Foundation Science Telemetry Types
12
Basic to Primary Processing

• CCSDS packets are processed into a number of
  working products
• Various databases on-time, spin-info and
  attitude history
• Event list (binary) files
• DE o9023.hide-1 .. o9023.hide-6 for the six
  IBEX-Hi ESA channels
• DE o9023.lode-1 .. o9023.lode-8 for the 8
  IBEX-Lo ESA channels
• HB o9023.hihb-1 .. o9023.hihb-6 for the
  histogram bins
• HB o9023.lohb-1 .. o9023.lohb-8 for the H and O
  histograms, and sectored monitor rates
• Also background monitor, star sensor and a few
  other types would be generated (if there was
  something to generate).
• exposure files (o9023.hi_exp and o9023.lo_exp)
  are generated to track exposure for each sky 6
  sky bin.
• DE's and HB's are stored in a compact, efficient
  binary (meta-event or ME) format.

13
Primary/Quick data Processing, 1

• The events are updated with aspect and IBEX
  location information so that they can be sliced
  and diced.

14
Primary/Quick data Processing, 2

• If this data were not fake, P/L housekeeping
  packets would also be passed to filters to
  provide
• Plots of various HK quanitites
• Backstop MAESTRO red/yellow alarm limits (ISOC
  orange limits)?
• 1D 2D TOF plots for lo
• Time filters on various detector counts to
  identify bad-time intervals
• ...
• Various standard quick-look plots are made to be
  provided on the web
• Great-circle skymap
• Counts by Spin-bin and Spin
• Raw count rates by DE or HB type

15
Quick Look Plots
Totally bogus J2000 counts on sky
Fake Magnetosphere at NEP
Totally bogus counts with time
16
Counting Rates for an Orbit

• For any pixel (in any geometry), for each of the
  14 ESA channels, we can estimate the counting
  rate

• In general, counts is a weighted sum of different
  event types (possibly including noise and
  background corrections).
• This can be calculated for any cull of events
  we choose to make (e.g. typically heliospheric or
  magnetospheric)?
• This is handled by a tool called hilo_cntrate

17
IBEX-Hi DE-1 (doubles) Rate
Counts
Exposure (ms)?
Rate (cts/s)?
(Ecliptic coordinates)?
18
IBEX-Hi DE-1 Nominal Flux
Flux (ENAs/cm² s sr keV

• Geometric/Energy factors
• Normalization conventions
• Tool hilo_gfactor

Rate (cts/s)?
(Ecliptic coordinates)?
19
Incident Flux at 1 AU

• We have 14 channels hide-1 .. hide-6, lode-1
  .. lode-8
• We have one (H) differential energy flux j(E) (O
  is later)?

• The channels are coupled through the sensor
  response

• Invertible? hilo_reflux

20
Orbit-Spin Frame

• The natural frame to work in for all of the above
  is a frame built around IBEX's mean spin for the
  orbit.

• For Direct Events the sky is well sampled in the
  spinward direction (a)?
• No information in the transverse direction (ß)?
• Our collimators are narrow enough that the
  effects are negligible for the moment. (A 1D FFT
  can be used if desired.)?

21
Follow Trajectory out to 100 AU

• Trajectory can be traced backwards
• This can be as simple or as complicated as you
  chose to make it

• Simplest is central-force, constant-µ used
• Can be easily made more complicated and complex
• Ram effects on energy are important
• Survivability is important
• Deflection angle (d) is exaggerated

22
Collecting Multiple Orbits

• Combining orbits can be done in any frame---I've
  used an ecliptic one here.
• I've exaggerated the deflection (d) for two
  orbits that are weeks apart
• The flux from pixels at 1 AU will contribute to
  one or more pixels at 100 AU.
• Different part of the band refer to different HS
  energies (E)?
• Tool flux_translate

23
Example Flux at 0.45 keV
24
Example Flux at 0.45 keV
25
Example Flux at 0.45 keV
26
Some Comments Here...

• Some comments on what I've shown you
• I've used 6hrs / orbit for my convenience
• These plots thus have serious Poisson noise
• primitive strategy for averaging contributions
  from multiple orbits
• Many projection options
• Some considerations for development
• Ram effects means that the same pixel will see a
  different energy on 2nd hit after 6 months. It
  takes a year to get the 3rd hit at the same E.
• With a flux model (e.g. a power-law) one could
  resolve mapped flux values to model-estimated
  values.
• These effects are least/most significant for
  IBEX-Hi/IBEX-Lo
• This will doubtless become a discussion topic
• The following slides step through IBEX-Hi from
  low to high E

27
IBEX-Hi at 0.45 keV
28
IBEX-Hi at 0.71 keV
29
IBEX-Hi at 1.11 keV
30
IBEX-Hi at 1.74 keV
31
IBEX-Hi at 2.73 keV
32
IBEX-Hi at 4.29 keV
33
Summary Status

• The output fluxes in the maps shown don't exactly
  match the input fluxes for trivial reasons that
  can be fixed once we've got completed response
  models.
• The flux_mapper tool was run with detailed
  trajectory calculations turned off. The
  flux_translate tool can use the same code (it's a
  reversible path) but that is not yet implemented.
• We plan to make these improvements and then fully
  test all the modules. Thereafter it can be used
  as an analysis tool.
• It can be used as a test-bed to evaluate the
  importance of various heliospheric properties for
  having an impact on our final results.

34
Pause

• General ISOC S/W Status

35
ISOC Software Status

• S/W Build 3.2 was made this week.
• Work on Build 3.3 has already started and we'll
  most likely use it during the first few orbits.
  Build 4.0 when we're ready.
• All critical functionality is in place.
• P/L housekeeping capabilities will be enhanced
  (significantly) during commissioning when we see
  real data in HVSCI mode
• Toolbox functionality (and help) is not as mature
  as I'd like, but it will improve during the
  initial orbits
• MS/HS cull capability is demonstrated but not
  thoroughly tested with real MS models.
• Still have significant work on IBEX-Lo response
  (O) IBEX-Hi is more mature, but still incomplete.

36
ISOC Software Status

• MOC-SOC interface is tested, but not fully
  automated (this is not a surprise, and also not a
  problem)?
• Basic Background/Noise issue analysis tools
  exist, but we'll have to wait and see what the
  first orbit(s) look like before putting them into
  the pipeline
• More routine orbit products are planned and may
  require the web page for each orbit to be split
  into several pieces
• ACS/Star Sensor tools exist but are not on web
  yet
• .... I'm sure there's something I've forgotten to
  mention ....
• We are GO FOR LAUNCH