70th Changing of the ISS Guard

NASA astronaut Loral O’Hara and Roscosmos cosmonauts Oleg Kononenko and Nikolai Chub arrived safely at the International Space Station (ISS), docking to the orbital facility’s Rassvet module at 18:56 Zulu on the evening of Friday, 15 September 2023. The trio’s arrival via the Soyuz MS-24 mission brought the space station’s crew complement to ten spacefarers.

The Soyuz 2.1a rocket by which Soyuz MS-24 was borne aloft lifted off from Site 31/6 of Russia’s Baikonur Cosmodrome at 15:44 Zulu—some three-hours prior to its arrival at the ISS.

O’Hara, Kononenko, and Chub were originally to have traveled to the space station aboard Soyuz MS-23 in February 2023. The flight was scrubbed in December 2022, however, after an inflight coolant leak discovered aboard the docked Soyuz MS-22 capsule compelled Roscosmos to dispatch the MS-23 spacecraft to the ISS sans crew.

Soyuz MS-22 eventually returned safely to Earth—also without a crew. Soyuz MS-23 and the Progress MS-22, 23, and 24 spacecraft have shown no signs of coolant leaks similar to those observed aboard Soyuz MS-22 and Progress MS-21 during their respective space-flights. Roscosmos has officially ascribed subject leaks to “external impacts.”

The MS-23 spacecraft will return Soyuz MS-22 crewmembers—Roscosmos cosmonauts Sergey Prokopyev and Dmitry Petelin and NASA astronaut Frank Rubio—to Earth following the men’s extended stays aboard the ISS. The return voyage is scheduled to depart the space station no earlier than 27 September 2023.

Prokopyev’s, Petelin’s, and Rubio’s departure from the ISS aboard Soyuz MS-23 will mark the end of Expedition 69 to the orbital installation. The Soyuz MS-24 crewmembers will thereafter join the Crew-7 astronauts as members of Expedition 70—as per the conventional process of changing flight increments aboard the ISS.

The Soyuz MS-24 mission occasioned the 11th Soyuz launch-vehicle flight of 2023. While the Soyuz rocket family has flown an estimated 1,900 missions since its 1966 debut, the vehicle’s (and Russia’s) overall launch cadence has diminished precipitously since its Soviet-era Cold War heyday.

Moreover, the Russo-Ukrainian conflict and sanctions imposed upon Russia in relation thereto have prompted launch customers the likes of OneWeb and the European Space Agency (ESA) to take their spaceflight business elsewhere, thereby limiting the use of Soyuz rockets to ISS crew and cargo support flights and Russian civilian and military payloads.

Notwithstanding geopolitical tensions deriving of the aforementioned Russo-Ukrainian conflict, the United States and the Russian Federation have agreed to go on flying each other’s nationals aboard their respective spacecraft. In addition to instantiating degrees of détente, the practice safeguards lives and national interests by ensuring the perpetuation of primary and redundant means of travel to and from the International Space Station.

FMI: www.nasa.gov/station