I would like to bring by daughter and her friend to the museum on Tuesday 3/10. Do I need to obtain passes or can we just come as walk ups. There will be 3 of us.

Weekdays you can come in without a pass but not before 1pm

The website says that you can walk in without passes on weekdays

Yeah you can go in but by metal detector s

It depends on the time of day. You CANNOT enter before 1 pm without a pass. I suggest you wake up around 630 am the day of to reserve passes or try to reserve in advance (tickets may be gone already). The museum is very large with many exhibits to see and walk up hours don't start til 1 pm during peak season leaving little time to see the full museum. Please refer to this link for more information. https://nmaahc.si.edu/visit/passes

You can walk right in