According to images broadcast live by the Russian space agency Roscosmos, the Soyuz 2.1B rocket carrying the Pritchal module took off on time at 13:06 GMT from the Russian Baikonur Cosmodrome in Kazakhstan.
The Pritchal ("Quay" in Russian) is to serve as a permanent mooring node for the Russian segment of the ISS alongside the Nauka ("Science" in Russian), a scientific module whose launch had been delayed by almost 15 years in due to technical setbacks.
The trip of the Pritchal to the orbital laboratory should last two days and its automatic docking to the Nauka module is scheduled for Friday.
In July, the docking of the Nauka was disrupted by the unexpected ignition of the module's engines, which had moved the ISS out of its normal position for a few minutes.
The Russian space sector has suffered since the fall of the USSR from funding problems, bureaucratic mistakes and corruption scandals.
Moscow has nevertheless multiplied the announcements of ambitious projects, such as the construction of its own space station to replace the ISS or that of a lunar base with China.
Russia sparked controversy last week by pulverizing an old Soviet satellite in orbit with a test missile fire.
A gesture denounced as dangerous by Washington.
© 2021 AFP