Zvezda can be refuelled by visiting Progress vehicles and used to boost the ISS.
Similarly, the Chinese Tianzhou can transfer propellant to Tiangong.
The Chinese Shijian satellites have also done refuelling.
Zvezda can be refuelled by visiting Progress vehicles and used to boost the ISS.
Similarly, the Chinese Tianzhou can transfer propellant to Tiangong.
The Chinese Shijian satellites have also done refuelling.