The Space Launch System (SLS) is a NASA rocket.
It is a heavy-lift launch vehicle.
It is the most powerful rocket ever built.
The SLS is a replacement for the retired Space Shuttle.
 Many parts are modified versions of parts designed for the Space Shuttle.
Others are new designs.

The first flight of the SLS will be in June 2020.
However, the first crewed (carrying people) flight will be in January 2023.
The Space Launch System (SLS) is a NASA rocket. It is a heavy-lift launch vehicle. It is the most powerful rocket ever built. The SLS is a replacement for the retired Space Shuttle.  Many parts are modified versions of parts designed for the Space Shuttle. Others are new designs.
The first flight of the SLS will be in June 2020. However, the first crewed (carrying people) flight will be in January 2023.
Space Launch System