A little while ago the Soyuz MS-25 spacecraft, which blasted off about two days ago from the Baikonur Cosmodrome in Kazakhstan, has reached the International Space Station carrying one new crew member and two visitors. Astronaut Tracy Dyson of NASA is part of Expedition 70/71 while cosmonaut Oleg Novitskiy of Roscosmos and the Belarusian Marina Vasilevskaya will remain on the Station for a few days.
According to original plans, the Soyuz MS-25 spacecraft was supposed to launch last Thursday and reach the International Space Station in just over three hours. However, the launch procedure was aborted within seconds from ignition, a rare case for the generally very reliable Soyuz rockets.
The computers monitoring the state of the Soyuz rocket detected low voltage in the first stage’s electrical system. Suspicion fell on some of the system’s batteries, which were replaced. The following tests were successful and the quick resolution of the problem allowed the launch to be rescheduled for Saturday.
For years now the Russian space agency Roscosmos has been using a fast track for the Soyuz spacecraft’s trips. Initially, a 6-hour track was tested and then there was a switch to the ultra-fast track of just over 3 hours but this requires a very precise series of maneuvers that are possible when the Station is in a certain position. Those conditions existed last Thursday, but by Saturday they had changed to the point that the Soyuz MS-25 spacecraft was forced to use the 2-day “slow” track.
After the Soyuz MS-25 spacecraft’s docking with the International Space Station’s Prichal module, the procedures that will lead to the opening of the hatch begun. Soon the newly-arrived will physically enter the Station, where they will be greeted by the crew with a short welcome ceremony.
The Soyuz MS-25 spacecraft is involved in an anomalous crew rotation on the International Space Station. When it returns to Earth in just over six months, only Tracy Caldwell-Dyson will still be aboard of the crew that used it to reach the Station. Oleg Novitsky and Marina Vasilevskaya will return to Earth on the Soyuz MS-24 spacecraft on April 2, barring schedule changes. Their seats on the Soyuz MS-25 will be taken by Oleg Kononenko and Nikolai Chub, who will complete a mission lasting about a year. The departure of Soyuz MS-24 will also mark the end of Expedition 70.
