WBS 3.3 Laser Facility
Jim Bell, Jason Chin, Erik Johansson, Chris Neyman, Viswa Velur
Design Meeting (Team meeting #10)
Sept 17th, 2007
Agenda
• Approach to Laser Facility WBS 3.3.
• Phasing of these subsystem deliveries and inputs
• Deliverables and products from subsystems (WBS 3.3.1 to
3.3.6)
• Laser Facility 3.3 internal interfaces and external
interfaces. Solicit inputs from members.
• Laser Down Selection Criteria to assist with determining
system architecture.
2
Approach
• Difficulty with designing without a basic architecture for the laser
architecture.
• Laser architectures and locations affect the enclosures, safety
system, and how the beam is transported to a centrally projected
launch telescope and the motion control related to the laser control
system.
• The selection of the laser is an important decision not just with
design impact, but with a sizable financial impact.
• Similar to the AO architecture product, some emphasis is needed to
provide an architecture with sufficient detail to drive the sub WBS.
• Team does not believe the laser decision can be made at this stage;
but a product of this WBS is to generate more information to assist
with the laser selection.
3
Phasing
•
WBS 3.3.1 System Architecture
– Generation of down select criteria and using them to provide a system
architecture with sufficient information to drive other WBS sub elements.
– WBS (3.3.2) Generation of Laser Enclosure Requirements and Concepts
– WBS (3.3.4) Generation of Laser Launch Facilities
– WBS (3.3.3) Laser Requirements and comparison of laser architecture with
LMCTI and SOR.
– WBS (3.3.5) Generation of Safety System and Concepts
– WBS (3.3.6) Laser Control System; dependency on 3.3.4.
4
WBS 3.3.1 Deliverables
• Laser System Architecture (80 hours) VV
– Provide down selection criteria
– Report of laser facility architecture's
• Layout of system architecture(s)
• Not expecting to point to one laser (LMCTI or SOR). Possibly
points to a laser on the elevation ring and/or a laser on the nasmyth
platform.
• Pros and Cons of the architecture(s)
• Determine feasibility of the architecture(s)
– Provide inputs for subsequent WBS 3.3.2 to 3.3.6.
5
WBS 3.3.2 Deliverables
• Laser Enclosure (80hrs) J. Bell
– Conceptual 3D model of the enclosure completed in Solidworks showing
spaces for:
•
Laser and laser transport optics, Supports, Electronics, Environmental
equipment and controls
– Design report will include
•
•
•
–
–
–
–
A first assessment of high risk items including requirement for higher reliability
due to limited access.
Interfaces to the enclosure including laser beam and infrastructures (power,
glycol, pneumatics, etc.); Safety Concerns
Estimated weight and weight distribution; effects on azimuth wrap
List of suitable vendors for proposed equipment
Preliminary cost analysis.
Inputs to the preliminary design phase WBS.
Updates and inputs to appropriate sections of FRD version 2, and System
Design Manual.
6
WBS 3.3.3 Deliverables
•
Laser (20 hrs. after re-plan, Requesting 40 hrs.) V. Velur
– A heuristic scaling law for the photon returns based on extrapolation/ past
experience will be formulated.
– A report summarizing the amount of laser power that will result in the
necessary return will be presented for the 2 possible lasers (LMCTI vs
SOR; will add fiber laser if there is time). All the effects, assumptions,
and the premise for the scaling law including how the Na-return changes
with spot size and laser power for each laser considered.
– Update of requirements and compliance of the two lasers for FRD 2.0
(laser section).
Justification for the hours: 10 hrs for scaling, 8 hrs. for laser power
calculation and 22 hrs for the document and applying scaling to varying
spot sizes and laser powers. And determine compliance with respect to
requirements.
7
WBS 3.3.4 Deliverables
•
Laser Launch Facility, Laser Beam Transport, Laser Pointing and
Diagnostics (200 hrs.) V. Velur
–
–
Report on the conceptual designs. To include a layout/block diagram as well as
description of the interfaces within and outside of the Laser Facility.
•
Concepts for Laser beam transport optics dependent on location of laser.
•
Concepts to generate nine laser beacons from a single or multiple lasers; provide losses
with pros and cons of the designs.
•
Concepts for pointing and steering of laser beams on sky, includes uplink tip/tilt and
maintaining asterism fixed on sky.
Launch Telescope
•
Optical requirements.
•
Modeling to determine feasibility as well as volume to fit into the telescope.
–
List of diagnostics for BTO and LLT; laser power, beam stability, spectral profile,
M2 measurements, and near and far field profiles.
–
Review and upgrade FRD requirements from version 1.0 to 2.0.
8
WBS 3.3.5 Deliverables
•
Safety System (40 hrs) J. Chin
– Use as much as possible from K1 LGS AO Safety System Requirements.
Changes will likely be those related to system architecture. Basic safety
concerns apply.
– A layout of the safety system with description of the individual subsystems.
The layout will include where subsystem components will be located;
dependency on the laser.
– Draft on how the conceptual design will meet the possible laser
architectures.
– Draft of an ICD describing possible interfaces between the subsystems
internal and external to 3.3.
– An updated version of the FRD v2.0.
9
WBS 3.3.6.2 Deliverables
•
Laser System SW (80 hrs) Erik J.
–
–
A revised WBS dictionary definition for this task.
An overall SW architecture design covering the main laser sequencer; command,
control and status interfaces to the various AO subsystems (the observing
sequence, AO sequence, etc.); the motion control system; calibration and
diagnostics. This design will be done in collaboration with the WBS tasks for
•
•
•
–
–
–
–
–
–
Science operations (3.4.1.2, 3.4.2.1, 3.4.2.2)
The laser system (3.3.1, 3.3.2, 3.3.3, 3.3.4)
The controls teams (3.2.4, 3.2.5)
A top-level block diagram showing the overall SW architecture for its main
subsystems.
A top-level data-flow diagram, showing data paths, descriptions, sizes, and
expected data rates.
A draft of an ICD for interfaces to laser SW; block level context diagram showing
laser SW components connectivity to AO system; high-level description of the
command, control, and status interfaces and functions of the laser sequencer.
A top-level description of all the laser component SW modules.
A revision of the functional requirements pertaining to the laser SW.
A report summarizing all the above items.
10
WBS 3.3.6.2 Deliverables
•
Laser System Electronics (70 hrs) Erik J.
–
–
–
A layout of the laser subsystems and their locations.
A block diagram of the laser control system
Block diagrams of the sub systems, to include:
•
Laser control
–
–
•
Motion control
–
–
–
–
–
Basic laser system control
Wavelength and mode control; detuning for Rayleigh background estimation
Beam transport; including beam injection.
Launch system
UTT
• Calibration and diagnostics
• Environmental system for laser and personnel
• Interfaces to the laser safety system
ICD Draft
Update to FRD 2.0
11
Block Diagram of External Interfaces
Supervisory
Controller
(3.4.2.4)
UTT Control/Position,
Shutter Control,
LGS Coordinate
Motions,
Laser Beams Steering,
Radial asterism
Wavefront
Controller
(3.2.5.3)
Drive and
Control (Tel,
sec, etc..)
Command &
Control,
Status,
Telemetry,
Shutter
Control
Laser Launch
Facility
3.3.4
Laser Control, Laser Status
Laser Safety System Status,
Pointing compensations
such as flexure, DCS
Information,
Laser Wavelength Tuning/
Detuning
Laser Controller
3.3.6
Command
& Control,
Status,
Telemetry
Fire Alarm,
Communication
Facility Infrastructure,
Intercoms
Safety System
3.3.5
Motion,
Offloading
WBS 3.3 Laser Facility
Emergency
Stop, Telescope
Positions
Telescope Drive and
Control
12
Block Diagram of Internal Interfaces
WBS 3.3 Laser
Facility
Laser Control
(3.3.6)
Command and control,
Motion Control,
Diagnostics
Command and Control
Diagnostics
Safety System Status
Laser Launch
Facility (3.3.4)
Safety System
(3.3.5)
Laser Beam
Transport
(3.3.4.1)
Personnel &
Equipment
(3.3.5.1)
Laser Pointing
& Diagnostics
(3.3.4.2)
Environmental
Status and Control
Interlocks
Aircraft, Sat.,
LTCS
(3.3.5.2)
Data
Archiver
Command &
Control
Interlocks
Shutters
Emergency
Shutdown
Environmental
Status and Control
Interlocks
Command and Control
Diagnostics
Status/Telemetry
Wavelength Tuning/
Detuning
Laser
(3.3.3)
Laser
Enclosure
(3.3.2)
Laser Launch
Telescope
(3.3.4.3)
13
How to make NGAO’s multimillion dollar
decision?
•
Generation of criteria and priorities in guiding the architecture
selection process
– Photon return per beacon (the photon return/watt isn’t as useful) - how
well it can optically pump the Na layer?
– $$ price for producing a single beacon (bang for the buck)
– Laser size, location (and ruggedness), BTO throughput.
– Operational cost, maintenance costs (replacement diodes may be ~$1M!),
failure modes (slow or catastrophic?)
– Laser reliability, system complexity.
– Upgradeability.
– Beam quality, spot size limitation imposed by the laser.
– SNR (fratricide and background may be lesser for pulsed lasers)
– How well do we understand the laser format and vouch for the Na return
(this is important when considering new laser formats).
– How well the laser technology is adaptable to techniques (like 2 color Na
pumping, Multi-color LGS to get rid of the tilt indeterminacy).
14
Previously criteria for subsystem evaluation
Evaluation Criteria
Performance Margin
Operations Cost
Development Cost
Cost Risk
Technical Risk
Reliability
Interfaces
System Expandability
Upgrade Applicability
Rankings =
Definition
Does this option meet the performance requirements and how much margin is
there?
Will this lead to low operations costs (procurement dollars and operations
personnel costs)? This should include maintainability.
What are the relative development costs (dollars)?
Is the risk to the development or operation costs low?
Is the risk to not meeting the performance requirements low?
Is the reliability of this option high? In particular, with respect to up-time of the
system.
Does this option impose a minimum of physical requirements and constraints
(physical space required, cabling, power, cooling, thermal management, ease
of implementation on telescope, etc.)?
Is this option easily scalable and does it offer future capabilities?
Can this option be implemented on the current Keck AO systems? Consider
the downtime to implement these upgrades in the evaluation.
Poor, fair, good & excellent.
Cost Evaluation
Rough Order of Magnitude cost in $k to produce the 1st unit. This should
include all Non-Recurring Engineering (NRE) costs. All design, labor,
subcontracts, prototype, lab test, etc. costs should be included.
Cost Estimate (1st unit)
It is adequate to have this at the +/- 50 or 100% level initially.
Cost Uncertainty
Unit Cost (2nd to nth unit) ROM to build each subsequent unit.
Any key information or assumptions used in estimating the costs.
Basis for Estimate
15