What is the market size for commercial space travel?

This is an estimation question

Step 1: Clarify:

1) I assume its sub-orbital space travel e.g. like the ones offered by Virgin Galatic and Blue Origin. 

2) Assumption- Virgin Galatic is pitting their target price of ticket would be 250K. I will consider 500K as the price of a ticket.

3) I will only target US geography

Step 2: Master Equation:

Number of high networth  households * number of people in a household healthy enough to take a space flight * % of individuals who would want to take a space flight * price of a ticket

Part 1- Number of high networth households = Total households * Household making an income of >$1 Mn/year

Total Households= Total Population/Avg size of household =330M/4= 82.5 Mn

Number of high networth households= 82.5 * 1%= 8.25Mn households -->A

Part 2- number of people in a household healthy enough to take a space flight =  2 individuals/household with ages <60 year=

23% of population is >60 years of age.

number of people in a household healthy enough to take a space flight = 8.25M *2*67% = ~ 11 Mn individuals

Part 3

% of individuals who would want to take a space flight will same as the number of peope who would be interested in extreme sports=5%

Hence, size of the market is 11 Mn * 5% * 500K/ticket = $275 Bn.