Conceptual Design Review Design Requirements The Systems Perspective Rob Hubbard Systems Engineering

The Flow-Down Process ATST Science Requirements Design Requirements

The Flow-Down Process ATST Science Requirements Design Requirements Strawman Concepts Functional and Performance Requirements

Getting to a Concept – Input Baseline Telescope Concept Strawman Concepts Experience with Similar Telescopes Funded Studies Trade Studies Engineering Analysis Obvious Constraints Work Shops

Getting to a Concept – Ideas

Testing the Concept Science Requirements Strawman Concept Error Budgets Sub-System Specs, Design Requirements Design and Development of Systems and Subsystems Performance Evaluation Cost Evaluation PDR Phase OK? (CoDR) Yes Conceptual Design Review: What passes this test? What work remains? No

Some Hard Constraints from the SRD Resolution, photon flux and sensitivity require a four-meter class telescope. Resolution requirement also leads to a high-order adaptive optics system. Wavelength coverage from 0.3 to 28  m leads to an all- reflecting telescope.

Some Challenging Requirements Resolution Requirement (Image Quality) –Even with a 4-meter aperture, a world-class site, high-order AO system, this remains challenging. Stray Light Requirement (Coronal Observations) Polarization Requirement (Polarimetry)

Design Requirements Documents M1 Mirror Assembly –SPEC-0007 (Ron Price) M2 Mirror Assembly –SPEC-0008 (Ron Price) Enclosure –SPEC-0010 (Mark Warner) Telescope Mount Assembly –SPEC-0011 (Mark Warner)

The Systems Approach The diverse and sometimes competing requirements placed on ATST forces a rigorous and aggressive systems approach during all phases of the project.

ATST Systems Orientation

Responsibilities of Systems Engineering Design Requirements Flow Down Document and Drawing Control Interface Control Error Budgets Standards End-to-End Modeling Quality Assurance Plan Acceptance Test Plans Integration Plan

Design Requirements Flow Down Document and Drawing Control Interface Control Error Budgets Standards End-to-End Modeling Quality Assurance Plan Acceptance Test Plans Integration Plan Responsibilities of Systems Engineering – CoDR Emphasis

Systems Overview Telescope Systems and Subsystems Definition Interface Control and the N 2 Diagram Documentation Control Error Budgets – Top Down Error Budgets – Bottom Up

Glossary and Acronym List

Document and Drawing Control

Interface Control and the N 2 Diagram

N 2 Diagram Detail

Top Level Systems 1.0Telescope Assembly 2.0Adaptive Optics 3.0Instrument Systems 4.0High-Level Controls and Software 5.0Enclosure 6.0Support Facility and Buildings

Telescope Assembly Subsystems 1.1Telescope Mount Assembly 1.2M1 Assembly 1.3M2 Assembly 1.4Feed Optics 1.5Thermal Systems 1.6Scattered Light Control Probably specific to D&D Phase. Likely to be reabsorbed later.