Attending: Jamie, Julian, Shaul, Karl, Qi
Notes: Karl + Shaul
Action Items
UMN will investigate the Open Dragone (anyone else interested in exploring optical design?)
Shaul will communicate with Amy re: shields, including spherex shields. (complete)
Kris assessing impact of combination of alpha+beta
Jamie will post spherex's deployable design on the JPL wiki (complete)
Comments on slides:
Slide 4: Jamie points out that EPIC focal plane has direct path to the sky, but perhaps there is also direct path after one reflection from the flat in the CORE case.
Slide 5: Jamie says that 'starting assumption' should be aperture >1 m. Currently the bullet implies that we will consider 0.5 m. Also, specific focal plane technologies should be left open, to encourage NASA technology funding into the future. Shaul agrees, but notes that we have to design around a specific baseline. Solution: have a baseline for costing and design, but be careful about what get set in stone or written formally as a requirement.
UMN took the EPIC 1.4 m design and put it within the envelope of the Falcon9. Shaul shows the opening angles and the shields, including the small folding shields.
Jamie mentioned SphereX folding shields are matching design. a possibility for CMBP
paper due out 'soon' from Doug Bolton.
Jamie will contact Doug about details and post shield design to internal JPL wiki.
Shaul says he will notify Amy.
Jamie suggest emphasizing that we need low precision shields, which should be high TRL. Low precision deployable solar panels are common on almost all satellites.
CORE shields were “book-like”, an open V. EPIC, Planck shields were cones.
Shaul will follow up with Amy: need to involve shield experts.
Scan strategy
EPIC was A = 45, B = 55. CORE was A=30, B=65
A + B > 90 is preferred, enables full sky maps per detector, helps control systematics
Julian: LiteBIRD memo has optimization for a range of angle for which A + B = 95. NERSC has capability to simulate full focal plan scans.
For now CMBP has A = 22, B = 78 works.
A > 22 only possible with deployable shields, or smaller telescope. UMN shows an option for A = 45, B = 55 with small extendables.
Optics
UMN show an 'Open Dragone' design that may be appealing in terms of baffling the focal plane from the sky.
Brief discussion of the temperature of the telescope. Jamie points to the EPIC study.