To place an outside call from space, please first dial 9.

As it turns out, the International Space Station is not immune to pesky phone protocols, and Dutch astronaut André Kuipers confessed to accidentally dialing 911 from orbit.

Kuipers revealed on Wednesday that in trying to make a call—by pressing 9 and then 011 for an international line—he missed a crucial number, triggering an alert at NASA’s Johnson Space Center in Houston, Texas.

“The next day I received an email message: Did you call 911?” Kuipers, a 60-year-old astronaut with the European Space Agency, told Dutch radio show Met Het Oog Op Morgen.

Astronauts on the ISS can place phone calls via a constellation of communication satellites and an IP phone that relies on internet protocol rather than a PTSN, or public switched telephone network. Using a form of “Space Skype,” they can easily dial Earth with a surprisingly clear connections, Geek pointed out in a 2013 conversation between NASA Flight Director Holly Riddings and Space Answers. The station even has its own Houston area code, according to the Washington Post.

While in orbit, astronauts not only use this connection to call friends and family, but to watch movies and read e-books as well.

Nevertheless, phoning home from space understandably has its limitations—audio delays and spotty connectivity, for example.

"Sometimes people were hanging up because they thought I did not say anything,” Kuipers said.

Kuipers isn’t the only astronaut to miss-dial, either. In 2015, Tim Peake, a British astronaut also with the European Space Agency, admitted to a similar goof.

“I'd like to apologise to the lady I just called by mistake saying ‘Hello, is this planet Earth?' - not a prank call...just a wrong number,” Peake tweeted.

Peake’s Italian colleague, astronaut Samantha Cristoforetti‏ replied, “Ha, ha! I called 911 once by mistake :-) Merry Christmas!”