Degradation of the thermal insulation of the Chandra spacecraft has resulted in significant restrictions in the durations of observations at various solar pitch angles. To produce a list of targets for which scheduling can be managed in the face of both thermal and user-imposed science constraints, a system for assessing the effective "resource cost" (RC) of each non-TOO observation has been devised. This RC is derived from both the position and any science constraint (see section 4.3 of the Cycle 22 Call for Proposals).
The RC will be calculated for all non-TOO targets. There is a cap on the total RC that will be accepted at the peer review. The RC for each proposal will be tracked at the Cycle 22 peer review. An RC quota will be weighted by the RC request in that panel, similar to observing time allocations.
The RC a target incurs scales with the exposure time (longer observations have a higher RC).
Targets near the ecliptic poles are difficult to schedule: therefore an observation without constraints may incur a non-zero RC by virtue of its position in the sky.
CPS gives the RC for all targets in a proposal - select "Review and Submit" from the menu on the LHS and then check the Slew Tax/Resources box.
RC will not be assigned to TOO proposals.
RC will replace "constraint categories" used in previous
Science Constraints: Section 4.4.
This section has been updated to note that RC will replace "constraint categories" used in previous Cycles.
High Ecliptic Latitude Targets: Section 4.5
This section has been updated to note that targets at high ecliptic latitude will incur a larger RC.
Target of Opportunity Projects: Section 4.6
All TOO follow-up observations (observations following an initial trigger observation) will count as half triggers for the purposes of counting triggers at the peer review - see Section 4.6 for more details.
TOO response times and the number of available triggers within each response category have changed. Please see Table 6.
Summary of Minor Updates
Sections 9.1.1 and 9.1.2
in previous Cycles the slew tax has been 1.5 ks for each 90 ks of observing time (e.g. a 100 ks observation is considered to be 90+10 for the purposes of assessing slew tax) . Going forward the slew tax will be based on 30 ks segments (Section 9.1.1). This new formula also applies to grid surveys (Section 9.1.2)