Orbitalwarehouse uses many great open source components, here are some of the major ones:

The very excellent Raphaeljs is used to render the SVG workspace.

Raphaël—JavaScript Library:
Jquery makes javascript easier.

jQuery: The Write Less, Do More, JavaScript Library:
Orbital WareHouse uses Nginx with PHP-fpm.

NGINX, Inc.:

PHP: Hypertext Preprocessor:
All data is backed into a Postgresql 9.1 database. Postgresql provides full text indexing for search facilities.

PostgreSQL: The world's most advanced open source database:
All servers are running Ubuntu Linux.

The Linux Kernel Archives:

Homepage | Ubuntu:
Etherpad Lite does awesome collaborative editing.

Twitter Bootstap makes responsive design 1000% easier: