NASA links to many Web sites created and maintained by other public and/or private organizations. NASA provides links to these sites as a service to our users. The presence of a link is not a NASA endorsement of the site.</p> <p>When users follow a link to an outside Web site, they are leaving NASA and are subject to the privacy and security policies of the owners/sponsors of the outside Web site(s). NASA is not responsible for the information collection practices of non-NASA sites.