After a customer has paid his or her first invoice, the average days to pay (ADTP) is calculated based on the number of invoices a customer has, the time taken to pay the first invoice, and the time taken to pay the most recent invoice. The formula for calculating the average days to pay is: ADTP = (Current ADTP) x (Number of Invoices) + (Number of Days Taken to Pay Most Recent Invoice) / (Number of Invoices + 1) The time it took to pay the first invoice would provide the initial value for the Current ADTP.
There are two paths to becoming an astronaut: 1  Become an US military pilot, and the best and safest pilot you can be. 2  Get a PhD in a subject that will be necessary in which to perform research in space, or to assist in building a new space station, or a space colony.
http://www.jsc.nasa.gov/Bios/ Are there age restrictions? There are no age restrictions for the program. Astronaut candidates selected in the past have ranged between the ages of 26 and 46, with the average age being 34. Do you have to be a U.S. citizen to apply for the Astronaut Candidate Program? Yes, you must be a U.S. citizen to apply for the program through NASA, applicants with valid U.S. dual-citizenship are also eligible. It is not recommended that you change your citizenship solely for the purpose of being eligible for the Astronaut Candidate Program.