Kickoff meetings for Definition Study

1
Inputs for LISA project response to the Science
Requirements Documents V0.3 (preliminary notes)
Marcello Sallusti (ESA) Tupper Hyde (NASA) Jordan
Evans (NASA)
2
Comments to SRD V0.3

• It is assumed that the requirements the project
  has to fulfill are the Measurement Requirements
  not the Observational Requirements.
•  Low frequency stretch (to 0.03 mHz, drives
  thermal stability and test/analysis issues). This
  is a potentially large dollar and potentially
  small mass cost upper.
• High frequency stretch (to 1 Hz, drives data rate
  to 3 Hz, otherwise 0.3 Hz would work and the
  science data rate would be 1/10 as much). This is
  a potentially large mass and/or dollar cost upper.

3
Comments to SRD V0.3

• Minimum mission requires 3 arms (this will mean
  meeting high reliability on each LOCS/LIMAS, as
  opposed to 2 arms for minimum mission which could
  mean losing a bench (or two) is OK and allowing
  less reliable benches). This is a huge mass and
  dollar cost upper (strict interpretation of
  single point failure requirement would require 4
  GRSs to be on each sciencecraft). Requirements
  should be given for the ability of determine GW
  polarization and sources direction, not on arms
  number.

4
Comments to SRD V0.3

• Verification binaries seem to be out of the
  minimum requirements set. Although requirements
  Smin2 and S1.1/S1.2 are similar, they lead to
  different strain sensitivity. To be clarified.
  However the frequency range for the minimum
  requirements spans at lower frequencies than
  those for which the symmetrized TDI Sagnac
  variable is insensitive to GW signal (below 30
  mHz). So Sagnac variable can in principle still
  be used for instrument noise characterization,
  but capability to calibrate LISA as an
  observatory might be lost.

5
Comments to SRD V0.3

• Data analysis inputs The final product to be
  made available to the scientific community has to
  be defined in detail. Final product it is assumed
  to be the strain measurement.
• Telemetry of science data if other data than
  Interferometer heterodyne (Sciencekeeping) are
  needed, these have to be specified. Sampling rate
  should be requested compatible to interpolate
  data within the MBW, not to a specific frequency.

6
Comments to SRD V0.3

• A requirement for Duty cycle gives way to
  several interpretations (and actual
  implementations). It needs to be clarified what
  is really meant.
• M1.2 is unclear. Verification Binaries and
  galactic background relationship is unclear. If
  the VB are below the background, no LISA
  sensitivity can save them
• Why three arms are necessary to measure
  polarization of EMRIs and VBs is not completely
  clear.