Default Exclusive Access Periods

Most HST and JWST programs have a default Exclusive Access Period (EAP) based on the size or class of the proposal. Certain Special Initiatives and other Proposal Types can alter the default EAP.

EAPs are per visit, so it is possible for the EAP on early visits to expire before later visits have been observed.

HST

In general, HST observations are granted the following default EAPs:

• Very Small, Small, and Medium GO programs: 6 months
• SNAP programs: 6 months
• Large GO programs: 0 months
• Treasury GO programs of any size: 0 months
• Calibration GO programs of any size: 0 months
• Calibration SNAP programs: 0 months
• DD programs: 0 months

Exceptions include but are not limited to:

• Hubble-Roman Science Initiative programs: 0 months, regardless of size
• HWO Precursor Science Initiative programs: 0 months, regardless of size

JWST

In general, JWST observations are granted the following default EAPs:

• Very Small, Small, and Medium GO programs: 12 months
• Survey programs: 12 months
• Large GO programs: 0 months
• Treasury GO programs of any size: 0 months
• Calibration GO programs of any size: 0 months
• Calibration SNAP programs: 0 months
• DD programs: 0 months

Exceptions include but are not limited to:

• JWST-Roman Science Initiative programs: 0 months, regardless of size
• HWO Precursor Science Initiative programs: 0 months, regardless of size

EAP Change Requests for Submitted Proposals

Longer and shorter EAPs can be requested at the time of submission and must be justified in the 'Special Requirements' section of the proposal.

Shorter EAPs require minimal justification, and are typically viewed favourably by the Telescope Allocation Committees (TACs).

Longer EAPs must be scientifically justified, and typically require an extremely compelling justification. These are rarely requested and seldom granted.

EAP Change Requests for Accepted Programs

Requests to change the EAP on an accepted program may only be made by the PI of the program. Requests must be submitted through the HST Help Desk or the JWST Help Desk, as appropriate. These will be reviewed by the Science Policy Division (SPD) and then a recommendation sent to the Director for a final decision.

Requests to reduce or remove the EAP on a program require minimal justification and are typically always granted.

Requests to extend the EAP on a program should be explict as to the reason why the request is being made. These are assessed carefully. As a matter of fairness, there is a very high bar set for extending EAPs. Typically, EAP extensions are reserved for truly exceptional situations.

Most requests are not approved. Examples of frequent requests that are not approved include:

• The PI, the Co-PI or a Co-I performing key work is a graduate student / the work is part of a thesis.

• The PI, the Co-PI or a Co-I performing key work is a postdoc.

• Allocation of funding has been delayed.

• The work has been delayed due to hiring timing.

• All observations have been taken, but early observations are due to become public before later observations.
• Some observations are due to become public before the final observations for the program are taken.
• Some observations failed and a HOPR/WOPR was required.
• The team is seeking additional data to supplement their HST or JWST observations.
• A team member other than the PI took parental leave.
• Serious health issues for a team member other than the PI.
• Serious personal emergency for a team member other than the PI.

Examples of requests that have been approved in the past include:

• The PI took parental leave.
• Serious health issues for the PI.
• Serious personal emergency for the PI.
• A team member passed away.

However, the final decision will depend on the details of the request and no request, even under the above circumstances, is guaranteed.