|Space Telescope Science Institute|
|Call for Proposals and HST Primer|
7.2 The HST Data ArchiveAll science and calibration data are placed in the HST Data Archive. Science data become immediately available (after pipeline processing) to a program’s Principal Investigator (PI), as well as those designated by the PI. These data may be retrieved after the PI has registered for an STScI single sign-on (SSO) account and are normally proprietary for a period of one year from the date of observation (see Section 5.1 of the Call for Proposals for information on data rights).As of August 1, 2014 the HST Data Archive contains over 101.91 Tbytes of data. The Archive consists of the on-line data store, the data storage appliance, which currently uses Ultra Density Optical disks, an off-site backup storage, also Ultra Density Optical disks, the Archive Catalog database tables and hardware and software that support ingest and distribution of the data.On average, science data from HST flow through the production pipeline and into the Archive within one day after observation on the telescope. Some data may take as long as three to five days. Observers are notified by e-mail when the first datasets reach the Archive. They are also provided with Web tools to track a visit’s completeness and to retrieve the data generated by the pipeline.The time required for retrieving data from the Archive depends on whether the data are available for direct download or need to be obtained through OTFR, the speed of the user’s connection, the size of the request data set and the load on the Archive.If there are strict scientific requirements for data receipt within days after execution, such as to provide pointing corrections for tightly scheduled visits, there are resource-intensive methods to expedite delivery of data. Such requirements must be stated in the proposal so that the resource needs can be determined and reviewed (see Section 9.3 of the Call for Proposals).7.2.1 Web Access to the HST Data ArchiveThe Archive may be accessed through a number of web-based interfaces. The MAST Portal provides a number of capabilities to search for, inspect, and download data. The Classic MAST search form, available under the “Mission Search” menu tab at the MAST Portal, allows qualified searches for HST data, and download of those data and their reference files. In both interfaces it is possible to request specific data products instead of the entire complement of files. Requesters of proprietary data will be required to log in to their accounts. Starview only allows searches of instrument-specific databases. When the single sign-on (SSO) capability is available, Starview will require users to obtain an account for accessing data.The MAST website allows previews of most publicly available images and spectra. Its interface includes integrated access to the Digitized Sky Survey (DSS) and enables users to access a coordinate resolver to look up the coordinates of an object by name.