Falcon heavy delay affects space station manifest

WASHINGTON – Delayed launches of commercial satellites aboard Falcon Heavy could disrupt the schedule of flights to the International Space Station, including a private astronaut mission scheduled for early May.

During a briefing on April 24 about the upcoming ISS spacewalk, a NASA official said that the Ax-2 mission to the station by Axiom Space, scheduled for May 8, may be pushed back.

“We’re trying to determine the best launch date for the Axiom mission right now,” said Dina Contella, operations integration manager for the ISS at NASA. “We are currently looking at what our options are.”

She said later in the briefing that the review was linked to delays in the launch of ViaSat-3 America’s Falcon Heavy and Astranis Arcturus satellites from Launch Complex 39A at Kennedy Space Center. The launch, previously scheduled for April 18, was delayed by SpaceX to April 26 after a steady-fire test of the rocket’s three boosters. The company did not disclose the reason for the delay.

That pad is also used for Falcon 9 cargo and crew missions to the ISS, but the conversion from Falcon Heavy to crewed Falcon 9 launches requires some work. “We will have to determine a new launch date for Axiom based on the turnaround of the pad,” Contella said. She said NASA is in discussions with SpaceX and Axiom Space about a new launch date, which could be announced in the next few days.

Crew Dragon has limited flexibility to reschedule Ax-2, a 10-day mission to the ISS that will carry four private astronauts, including two from Saudi Arabia. One cargo mission, SpaceX CRS-28, is currently scheduled to launch on June 3, and Contella said NASA wants to keep that cargo mission on schedule.

“We’re trying, if we can, to leave SpaceX CRS-28 on June 3,” she said. It is carrying another pair of new solar arrays for the mission station that will be installed on two spacewalks. NASA wants to complete that spacewalk by early July, when the station enters a “high beta” period with extended illumination. “If we can complete that entire mission before high beta, it will be selected.”

It is unclear what will happen if Ax-2 cannot be rescheduled for the CRS-28 cargo mission. CRS-28 is the crewed flight test mission of Boeing’s CST-100 Starliner, currently scheduled for July 21, followed by Crew-7, the Crew Dragon mission for NASA, in mid-August. The agency confirmed the April 14 launch dates for the two in a manifest that also includes Crew-8 in February 2024 and Starliner-1 in mid-2024.

Contella added that NASA also hopes to launch another Cygnus mission, NG-19, to the station sometime this summer. NG-18 Cygnus was ejected by the station’s robotic arm and released on April 21, later re-entering. Cygnus, however, uses a different docking port than the two docking ports for Dragon, Crew Dragon, and Starliner spacecraft, giving NASA more schedule flexibility.

The April 28 spacewalk by NASA astronaut Steve Bowen and UAE astronaut Sultan Al Nayadi will do some preliminary work for the upcoming solar array spacewalk, including installing cables and fixing insulation “that’s not quite aligned,” Contella said. They will set up equipment during their spacewalk “so that the June spacewalk can go as planned.”

Bowen and Alneyadi will also retrieve a large S-band antenna, carrying it inside the station so that it can be returned to Earth for refurbishment. The spacewalk will be the first by Alneadi or any Emirati astronaut and the eighth by Bowen.

Those activities will take place as engineers continue to review data on coolant leaks suffered by the Soyuz spacecraft in December and by the Progress spacecraft in February, both docked at the station.

“We have no new news to report”, she said on the Roscosmos investigation into the leaks, including whether the two leaks had a common cause. “They are investigating and we are working closely with them.”