The Project Office Perspective
Antonin Bouchez
GMT AO Workshop, Canberra 22-24 Nov. 2010
1
Outline
1.
2.
3.
4.
5.
Project Status
AO requirements
Baseline Design
Unresolved technical issues
Meeting goals
GMT AO Workshop, Canberra 22-24 Nov. 2010
2
Project Status
•
•
•
•
We’re working towards project PDR in “early” 2012.
AO PDR must precede this; planning for Dec. 2011.
New project manager Keith Raybould starts Dec. 6.
Major replanning effort has begun
- Restructured WBS
- Bottoms-up cost estimate (to complete by January 2011)
• Previous cost estimate for AO: $58.6 M (2004 $)
- Schedule through construction (complete ~March 2011?)
• Current direction from management: Design to the the
science requirements, without cost constraint.
GMT AO Workshop, Canberra 22-24 Nov. 2010
3
Thoughts on AO project management
• AO system will likely cost ~$75M. Most of this work will
have to be done by industry.
• However, AO/instrument groups at partner institutions
provide experience, design expertise, and an ideal
environment for technology development and testing.
• We’re very aware that project organization, systems
engineering, and communications must be improved.
• Launching online communications tools (Basecamp)
• Hiring additional systems engineers
• Instituting a change control board
GMT AO Workshop, Canberra 22-24 Nov. 2010
4
Top-level performance requirements
Mode
Description
Natural Guide Star AO High Strehl over a narrow field of view using bright guide stars.
(NGSAO)
Requirement: 160 nm RMS WFE for R<8 stars.
Laser Tomography AO Moderate Strehl over narrow field of view with high sky coverage
(LTAO)
Requirement: 200 nm RMS WFE over 80% of sky at b=50°.
Ground Layer AO
(GLAO)
Image improvement over very wide field of view by correcting
only low-altitude turbulence.
Goal: 2-4x image size reduction in near-IR over 8’ diameter.
Additional Requirements:
• Shall not preclude future implementation of MCAO and MOAO observing modes.
• AO system shall have <20% emissivity (<10% goal).
GMT AO Workshop, Canberra 22-24 Nov. 2010
5
Instrument-specific Requirements
• 4 instruments currently being studied, with a wide range of AO
requirements not captured in top-level requirements:
GMTIFS
NGS/LTAO with strict tip/tilt requirements
GMTNIRS
NGS/LTAO with loose tip/tilt requirements
TIGER
High Strehl – potentially NGS only
NIRMOS
GLAO only
• Challenge for AO team is to design a single system which will suit
any 1-2 of these which are selected for 1st light construction.
• Our strategy:
-
-
Design common components (ASM, lasers, RTC) which meet the most stringent
requirement.
Design a suite of sensors which can meet requirements of each mode, and
assume that the selected instruments will only implement certain sensors.
Do this with minimum duplication of effort: eg. only 1 IR-WFS design.
GMT AO Workshop, Canberra 22-24 Nov. 2010
6
AO System Baseline Design
On-axis LGS
Projector
7x672 actuator adaptive
secondary mirror
Wavefront sensors:
top view
Free space
beam relay
Lasers:
6x30W CW + spare
• Visible WFS modules attach
to front of instruments: 1
HO-WFS, 3 LO-WFS, 6
LGS-WFS
• 1 IR-WFS internal to
instrument which require
high sky coverage
• 1 Optical Phasing Sensor
common to all instruments
Separate GLAO dichroic
& LGS-WFS assembly
GMT AO Workshop, Canberra 22-24 Nov. 2010
7
Phasing System Baseline Design
• GLAO: No phasing necessary
• NGSAO: Use a pyramid NGS sensor to sense both telescope &
atmospheric piston.
• LTAO: Slow (~1 min) Optical Piston Sensor with large patrol area +
fast (100 Hz) relative metrology of adjacent segments. Average
over atmospheric piston and accept 120 nm RMS WFE.
Various alternative LTAO piston sensing approaches have been
discussed, but none demonstrated to be sufficiently general.
GMT AO Workshop, Canberra 22-24 Nov. 2010
8
AO System Design Effort
• 5 components to the preliminary design effort:
UA
NGSAO and GLAO subsystems
ANU
LTAO subsystems
SAO
Optical phasing sensor
ADS/MG
Adaptive secondary mirror
Proj. Office
Systems engineering, edge sensors
• Potential additional design contracts to industry: Realtime computer, …
GMT AO Workshop, Canberra 22-24 Nov. 2010
9
Unresolved Technical Questions
• Sky coverage & NGS sensor architecture…
• Can we develop an IR WFS design which suits all
instrument’s needs?
• Are any of the alternative LTAO optical piston sensor
approaches worth pursuing?
• Need to define and simulate interaction between AO and
piston control loops.
• Are active optics WFS necessary/useful in NGSAO or
LTAO control loop?
• Could active optics WFS be sufficient for all NGS
sensing in GLAO mode?
GMT AO Workshop, Canberra 22-24 Nov. 2010
10
[My] Meeting Goals
• We agree on a baseline design, including which aspects
are yet to be defined.
• We agree on various groups’ responsibilities for the
preliminary design phase, and the critical interfaces
between these subsystems.
• We set up a schedule for communication between
groups on design & interfaces.
• We compile a list of the technical questions which need
to be resolved, and assign these to individuals.
• We compile a list of management and systems
engineering issues which the project office must
address.
GMT AO Workshop, Canberra 22-24 Nov. 2010
12
End
GMT AO Workshop, Canberra 22-24 Nov. 2010
13