The Tertiary Mirror System (“M3S”) Planning Study RFP Clarifications.

The Following are the TMT responses to requests for clarification of the M3S RFP:

M3S Design Requirements Document – Exhibit A:

1. Section 2.1 Perspective: The second word in the second sentence should read M3S, not M2S.

2. Section 2.1 Perspective: In the third paragraph, "cleaning of the mirror with C snow" should read "cleaning of the mirror with CO2 snow."

Q. Section 2.2 System Functions: There is a discussion of the diagnostic mode for the M3CSP and M3CSC.  Please provide a more complete overview of the diagnostic mode.

A. The term “diagnostic mode” for the M3CSP and M3CSC is for the self test but it has not been fully defined at this time.

Q. Section 2.2 System Functions: Is the tilt actuator concept depicted on page 9 of Exhibit A the preferred method of tilting the M3?

A. The tilt actuator concept depicted on page 9 is only one of many that were considered for the TMT Conceptual Design Review. Any actuator design that meets the M3S DRD requirements is allowed.

Q. Section 3.1.5 Thermal Control: There is a maximum coolant temperature rise requirement, but there is no flow rate limitation.  Is there a coolant max flow rate to the M3S?

A. There is no coolant max flow rate requirement to the M3S. There will be an electrical power budget and a requirement for a power efficient design.

Q. [REQ-2-M3-0245] Would it be appropriate to designate the “higher than 15Hz” requirement as an objective rather than a threshold requirement?

A. The 15Hz lowest resonant frequency for M3S is an important requirement.  Further dynamic seismic analysis of the telescope structure, planned for early 2008 will clarify whether it can be relaxed.

Q. [REQ-2-M3-0780] Who defines the data format for telemetry provided to the TCS?  Will TMT provide a global interface control document to which the M3CSC will have to adhere?

A. TMT will work with the contractor to develop a global interface control document (ICD) to which the M3CSC will have to adhere.

Q. Section 3.3.2 M3 Control System - Positioner (M3CSP): Is the M3 Control System - Positioner (M3CSP) expected to perform open-loop, i.e., when slewing from one science instrument to another, or will the TCS provide commands for the entire slew trajectory?

A. The M3PA shall be able to follow an acceleration/deceleration limited slew trajectory via position commands from the TCS. The M3PA shall also respond appropriately to step position commands from the TCS, via an acceleration/deceleration limited profile.

Q. [REQ-2-M3-1086] Should the reference be to [REQ-2-M3-0670] instead of [REQ-2-M3-0672]?

A. Correct.  The locking feature requirement for M3CSP is described in [REQ-2-M3-0670] not [REQ-2-M3-0672].

Observatory Architecture Document

Q. [REQ-1-OAD-2020] Is the reference to “Section 0” correct?

A. No, the reference to “Section 0” is incorrect.  The reference should read “Section 4.1.3.7.2 and [REQ-1-OAD-2000].

Suppliers are encouraged to check this page regularly for any modifications, additions or new information regarding the TMT M3S Planning Study RFP.

Thank you,