Heliophysics research often requires the use of
a variety of observational and model artifacts to study
processes relating to mass and energy transfer across
different heliophysics domains. The Heliophysics Digital
Observatory (HDO) unifies several legacy discipline-oriented
heliophysics virtual observatories via a more streamlined and
intuitive middleware system that takes advantage of the Space
Physics Archive Search and Extract (SPASE) metadata and focuses on
delivering higher-level data search and discovery
capabilities beyond those of existing data services. SPASE
metadata enables HDO to search/discover, locate and access
multi-disciplinary data and model artifacts simultaneously
from distributed repositories. The HDO functionalities
supporting the NASA Heliophysics science goals are summarized below:

1) Search, locate, and access multi-disciplinary heliophysics digital
resources (observational and model artifacts) to support research. 

2) Support systems science research by providing simultaneous access
to multi-disciplinary resources for multiple time intervals based 
on (a) solar wind and geomagnetic conditions, (b) observing platform
locations, and (c) phenomenon-based event lists. 

3) The HDO built-in magnetospheric-state query system (MSQS) allows
resource searching by solar wind, IMF and geomagnetic conditions,
extreme or otherwise.

HDO Query Builder interface enables access to data
products via a time-range selection;
users may alternatively choose to upload an event list
of time ranges. The resultant time ranges may be filtered
by domain resource type (Solar, Heliospheric,
Magnetospheric, ITM and Wave), magnetospheric state (MSQS)
and/or by spacecraft location (via access to the SPDF/Satellite Situation
Center). The resultant data products may be further filtered by
resource type (Numerical, Display, Catalog, etc.). The main
panel displays the available products and provides download
access while the left sidebar captures all user selections and filters.