| Version |
$Revision: 1.4 $ |
| Last Update |
$Date: 2001/11/08 14:46:10 $ |
| HRC CCB Status |
not reviewed |
Number: HRC-L-002
Type: Limitation
Original Date: 1998 March 20
Subsystem: HRC
Subject: Closing the HRC Housing Door
Source:
CRL Statement:
The HRC detector housing door should not be closed.
CRL Rationale/Justification:
Closing the HRC door may result in a pressure buildup in the detector due to
component outgassing. The pressure may be high enough to damage the MCPs, if
the HV is on or turned on while the door is closed or, if it is turned on too
soon after the door is opened. In addition, the only severe loads on the door
mechanism occur when the door is closed. While the door mechanism has been
designed and tested to verify that it can be closed and reopened on-orbit, if
there is no operational necessity to close it, it is good practice to minimize
stressing the mechanism. If the door should fail closed, there is no failsafe
feature to open it!
CRL Impact:
Possible damage to the MCPs, if HV is on or turned on at too high a pressure
due to door being closed. If the HRC housing door cannot be reopened,
observational use of the HRC instrument is lost.
Recommended Action:
Incorporate into the Systems and Operations Procedures.
$Log: hrc-l-001.html,v $
Revision 1.4 2001/11/08 14:46:10 juda
HTML "href" tag edits to convert to soft links
Revision 1.3 1998/06/17 18:45:47 juda
Updated restriction number to agree with TRW CARD (HRC-L-001? replaced with HRC-L-002)
Revision 1.2 1998/04/27 14:01:47 juda
Added Version table
Page created 1998 March 20
Dr. Michael
Juda
Harvard-Smithsonian Center for Astrophysics
60 Garden Street, Mail Stop 70
Cambridge, MA 02138, USA
Ph.: (617) 495-7062
Fax: (617) 495-7356
E-mail: mjuda@cfa.harvard.edu