LISA Science Requirements: An Update

1
LISA Science Requirements An Update

• Tom Prince
• LISA Science Team Meeting
• July 5-6, 2003

2
Science Requirements Whats new?

• Project Science Requirements Document drafted
  (May 15, 2003)
• Derived from LIST Science Requirements Document
• Incorporates some format elements developed
  during TRIP process
• Meant to serve as part of the requirements
  flow-down documentation
• Separates Science Requirements and Measurement
  Requirements
• Attempt to link all Measurement Requirements to
  one or more Science Requirements
• Inclusion of a high-frequency requirement (_at_
  0.1 Hz)
• LIST should comment

3
Science Requirements Issues

• High-frequency requirement
• LIST to comment
• Low-frequency requirement
• Requires discussion
• Previous LIST document on low-frequency
  performance
• Need to formulate quantitative measurement
  requirement linked to science requirement
• How should science goals be treated?
• Currently nominal mission requirements and
  minimum requirements
• Add goals to document?
• How should minimum requirements be treated
• Discussions have pointed out that there are 2
  types of minimum requirements minimum design
  requirements and minimum success criteria

4
High-Frequency Requirement (0.1 Hz)
5
Low-Frequency Requirements

• LIST document recommended that the LISA noise
  goals are reached in the range 0.03-1 mHz
• Issue
• Must specify quantitatively the LISA noise goal
  at 0.03 mHz
• Clarify science rationale

6
Minimum Requirements Revisited

• Need to be clear whether minimum requirements
  are
• Design/implementation minimums, or
• Minimum success criteria
• Example number of arms for LISA
• 3 arms (6 links) is a requirement of the design
  and the implementation
• 2 arms (4 links) should fulfill the minimum
  success criteria
• Recommendation
• Make distinction explicit in LISA Project
  Documents
• Work with ESA and NASA HQ to provide appropriate
  minimum requirements for various documents, e.g.
  Level 1 requirements

7
Minimum Requirements (current statement)