MAST has several options retrieving data, with some missions having more options than others.
MAST Data Discovery Portal
The MAST Data Discovery Portal (aka MAST Portal) is found at https://mast.stci.edu . The default search on the MAST Portal is by coordinates, or by the name of a target that gets resolved into coordinates. You can also upload a list of targets. Users who wish to search by other types of metadata, such as proposal ID, mission name, filter, or proposer name must use the advanced search option. The portal provides users the ability to download data directly to their systems, either through the browser or by generating a cURL script that can be executed on the user’s system.
Detailed instructions for using the MAST Data Discovery Portal can be found in the Portal User Guide.
An overview of the retrieval options when using the Portal can be found in the Retrieval Methods section.
MAST API
The MAST application programming interface (API) enables programmatic access to search for and retrieve MAST datasets.
astroquery.mast is a user-friendly Python package that wraps the MAST API, and is recommended for most users.
The older-generation, mission-specific search forms are referred to as "MAST Classic" forms. These forms remain available to users while the collections are brought into our modern search forms. You can find the Classic search forms by visiting the listing of Classic search forms.