1. ESA’s Darwin Web Site, http://sci.esa.int/home/darwin/index.cfm
2. NASA’s Origins Web Site, http://origins.jpl.nasa.gov
3. S. Lubow, Controlling the NGST Orbit, http://icarus.stsci.edu/∼lubow/ngst/orbits.html
4. The TPF Science Working Group, Terrestrial Planet Finder, NASA/JPL Publication 99-3, May 1999
5. NASA’s SIRTF Web Site, http://sirtf.caltech.edu/