WFPC2 Contingency Contamination Plan
After release, WFPC2 will be recovered from Protect Safemode to Hold via stored
commanding. A real-time microprocessor dump of RAM will be executed and verified.
After a successful RAM verification, the SMS will transition WFPC2 to Protect Decon.
No observations or cool-down of the chips during BEA.
Health & Safety
End of BEA
Protect
Recover to Hold, RAM verification, transition to Protect Decon
Safemode
After the BEA, release plus 12 days, WFPC2 will leave protect decon and the chips will
be cooled down to –88 degrees. UV monitoring will start by taking exposures with
F555W and F170W. During the first 24 hours after cool down, the SSR will need to be
dumped after each set of exposures, and will be required to have a quick turnaround of
the data.
1
Colleen Townsley
WFPC2 Contingency Contamination Plan
Default schedule if no contamination is seen during any of the exposures:
Quick look data of first 24 hours of exposures after leaving BEA and cool down of chips:
0 hours
3 hours
6 hours
12 hours
18 hours
24 hours
T w o d a y ve rific a tio n p e rio d
1 2 h o u r tu rn a ro u n d
1 2 h o u r tu rn a ro u n d
T im e b e tw e e n o b s e rv a tio n s
1 .5 d a ys
2 d a ys
3 d a ys
U V m o n ito r
4 d a ys
5 d a ys
6 d a ys
8 d a ys
1 0 d a ys
1 2 d a ys
1 4 d a ys
1 6 d a ys
2 0 d a ys
U V m o n ito r
2 4 d a ys
2 8 d a ys
WFPC2 Real-time Contingency Plan * if contamination exceeds 30% in F170:
A) Prepare to SAFE WFPC2
1) Close shutter if both blades are open.
2) Select filter 785LP
3) Safe WFPC2
4) Turn on heat pipe heater unless following steps can be executed within 2 hours.
B) Recover WFPC2 and put in decon
5) Recover WFPC2 to Hold
6) Turn on CCD heaters
7) Turn on heat pipe heater
8) If WFPC2 commanding is in remainder of SMS, set WFPC2 safing bit to ignore
SMS stored commanding,
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Colleen Townsley
WFPC2 Contingency Contamination Plan
C) WFPC2 remains in decon for 3-4 days
D) If WFPC2 safing bit was set to ignore SMS stored commanding, the safing bit would
need to be re-patched to enable stored commanding.
E) Replan SMS would need to be generated to have the WFPC2 CCDs cool down to –88
degrees and images taken and analyzed for contamination.
*Note: Script with real-time procedures will need to be drafted and tested on MASIS.
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Colleen Townsley