WASHINGTON — The International Astronautical Federation is ready for one of its biggest conferences ever this week, even as organizers deal with political and geopolitical issues about the event.

The 70th International Astronautical Congress (IAC) formally starts here Oct. 21, with more than 6,300 people registered to attend, representatives of the IAF and the American Institute of Aeronautics and Astronautics (AIAA), the host organization for the event, said during a press conference here Oct. 20.

The event’s highlights include a heads-of-agencies panel Oct. 21 that includes NASA Administrator Jim Bridenstine along with representatives from space agencies in Canada, China, Europe, India, Japan and Russia. Jeff Bezos, the billionaire founder of Blue Origin, will receive the IAF’s first “Excellence in Industry” award at a ceremony Oct. 22.

The most prominent participant in the event, though, will be Vice President Mike Pence, who will speak at the conference’s opening ceremony Oct. 21. Pence’s appearance, announced earlier this month by conference organizers, has attracted some criticism because of Pence’s stance on social issues.

An online petition published Oct. 19 called on the IAF to rescind Pence’s invitation to speak because of his views. Organizers said they planned to walk out of the opening ceremonies when Pence speaks at about 10:15 a.m. Eastern. More than 150 people have signed the petition as of the afternoon of Oct. 20, although it’s not clear how many will be at the conference.

Conference organizers, who said they were “very proud” that Pence was participating, defended the decision to invite him at the pre-event press conference. Dan Dumbacher, executive director of AIAA, said Pence was invited in his role as chairman of the National Space Council. “It’s very appropriate for the audience here at the IAC to hear from the chair of the National Space Council,” he said.

“AIAA values diversity and inclusion. It is one of our prime efforts in the institute,” he added. “We value all the voices. Vice President Pence is a voice, and there are other voices, and we want all the voices here.”

Lucianne Walkowicz, an astronomer at the Adler Planetarium and one of the organizers of the petition, said Oct. 20 she wasn’t sure how many people might participate in any protest at the opening ceremony. She believed some people felt constrained by industry affiliations from participating, while others may decide simply not to attend the opening ceremony.

Any protest would be rare for an IAC or other space industry event. Pence has spoken at other space industry conferences, including the Satellite 2019 conference in May in the same convention center that’s hosting IAC, as well as the Space Symposium in Colorado Springs in April 2018, without incident.

IAC organizers have also had to deal with another issue that’s become common in recent years: securing visas for attendees from some nations, notably China and Russia. Vincent Boles, co-chair of the local organizing committee for the 2019 IAC, said his committee started working with the U.S. State Department 18 months ago to ensure that visas would be ready in time for attendees.

Boles said they expected a “very high attendance rate” from China and Russia at the IAC. That includes Wu Yanhua, vice administrator of the China National Space Administration, who is scheduled to speak at the heads-of-agencies panel.

Sergey Krikalev, executive director for piloted spaceflights for Roscosmos, will represent his agency at that panel. Dmitry Rogozin, head of Roscosmos, remains barred from entering the United States because of sanctions imposed from his role as deputy prime minister when Russian annexed Crimea in 2014.

Conference organizers hope that the IAC’s location will help win support for NASA’s space exploration plans from members of Congress. AIAA and other organizations started holding briefings about the IAC on Capitol Hill months ago for members and their staffs, and plans to offer tours of the exhibit hall and other opportunities during the week-long conference for members and staffers.

“It’s the perfect time to engage Congressional members and make them aware of the strengths of the U.S. space industry and the importance of international collaboration,” Boles said.