How do I get permission to use an "Available mode"?

Available modes often facilitate specific science goals at the expense of other archival science applications. For example, suppressing a wavelength calibration exposure allows a slightly longer science exposure, but then archival users will never be able to retrieve a reduced spectrum from the HST archive. The small increase in S/N ratio usually does not compensate for this loss in archival value. If your science requires an available mode, please read the available mode usage policy and then send a request for available mode approval to help@stsci.edu.