The Heliophysics Digital Observatory (HDO): Providing Enhanced High-Level Data Search Capabilities

We describe an effort to develop the NASA heliophysics digital observatory (HDO) by consolidating and streamlining several discipline-oriented heliophysics virtual observatories (VxOs) that were established over 15 years ago. The HDO will take full advantage of the Space Physics Archive and Extract (SPASE) metadata model (https://spase-group.org) and focus on developing and implementing higher-level data search capabilities so as not to be duplicative of existing data services. The VxOs, with x representing any heliophysics subdiscipline, were generally developed as middleware for providing services to users to search, locate and access discipline-oriented data resources that are stored in distributed repositories. Because of discipline-orientation, certain general functionalities had to be duplicated across different VxOs and maintained separately. As technology advances, a few of the original VxOs with obsolete architecture have become difficult to maintain and operate. We have now taken steps to consolidate those VxOs developed at the NASA Goddard Space Flight Center, namely the virtual heliospheric, magnetospheric, and wave observatories, into a single virtual observatory, the HDO. In doing so, we are preserving all the advantages and rationale of the virtual observatory paradigm, but with a more streamlined middleware system.