Mr. Hardin said the bank access from space was an attempt to make sure that there were sufficient funds in Ms. Worden’s account to pay bills and care for the child they had been raising. Ms. McClain had done the same throughout the relationship, he said, with Ms. Worden’s full knowledge. Ms. McClain continued using the password that she had used previously and never heard from Ms. Worden that the account was now off limits, he added.

A complaint involving bank access from the space station is just one of a number of complex legal issues that have emerged in the age of routine space travel, issues that are expected to grow with the onset of space tourism.

In 2011, NASA organized a sting operation targeting a space engineer’s widow who was looking to sell a moon rock. In 2013, a Russian satellite was damaged after colliding with debris from a satellite that China had destroyed in a 2007 missile test. In 2017, an Austrian businessman sued a space tourism company, seeking to recover his deposit for a planned trip that was not progressing.

“Just because it’s in space doesn’t mean it’s not subject to law,” Mr. Sundahl said.

One potential issue that could arise with any criminal case or lawsuit over extraterrestrial bank communications, Mr. Sundahl said, is discovery: NASA officials would be wary of opening up highly sensitive computer networks to examination by lawyers, for example. But those sorts of legal questions, he said, are going to be inevitable as people spend more time in outer space.

The couple’s dispute revolved largely around Ms. Worden’s son, who was born about a year before the two met.

Ms. Worden, who had previously worked at the National Security Agency, resisted allowing Ms. McClain to adopt the child, even after they were married at the end of 2014.