Invitation Letters from the National Space Society:
In order to attend the ISDC as a visitor from another country, you may need to obtain an invitation letter from the NSS. (If you will require a visa to enter the U.S., you must have this letter.) If you are attending in connection with an NSS space contest, such as the Gerard K. O’Neill Space Settlement Contest or the “Live in a Healthy Space” Design Competition, please use the Contest online form. For all other ISDC attendees, please request your invitation letter using the Non-Contest online form.
