The Space Launch System (SLS) is a US super heavy-lift expendable launch vehicle, which has been under development since its announcement in 2011.

The main launch vehicle planned to be used for the Artemis lunar program, as of May 2020 is the US Space Launch System (SLS).
NASA is required to utilize SLS Block 1 by the US Congress to lift a payload of 95 metric tons (209,000 lb) to low Earth orbit (LEO), and will launch Artemis 1, 2, and 3.
The later Block 1B is intended to debut the Exploration Upper Stage and launch the notional Artemis 4-7.
Block 2 is planned to replace the initial Shuttle-derived boosters with advanced boosters and would have a LEO capability of more than 150 metric tons (330,000 lb), again as required by Congress.
Block 2 is intended to enable crewed launches to Mars.
The SLS will launch the Orion spacecraft and use the ground operations capabilities and launch facilities at NASA's Kennedy Space Center in Florida.
Some variations of the SLS launch manifest has all the blocks being active at the same time rather than one block replacing the last as is common with launchers.

In March 2019, the Trump Administration released its Fiscal Year 2020 Budget Request for NASA.
This budget did not initially include any money for the Block 1B and Block 2 variants of SLS but later a request for a budget increase of 1.6 billion dollars towards SLS, Orion, and crewed landers was made.
Block 1B is currently intended to debut on Artemis 4 and will be used mainly for co-manifested crew transfers and logistics rather than constructing the Gateway as initially planned.
An uncrewed Block was planned to launch the Lunar Surface Asset in 2028, the first lunar outpost of the Artemis program, but now that launch has been moved to a commercial launcher.
Block 2 development will most likely start in the late 2020s after NASA is regularly visiting the lunar surface and shifts focus towards Mars.

In October 2019, it was announced NASA had authorized Boeing to purchase materials in bulk for more SLS rockets ahead of the announcement of a new contract.
This contract is expected to support up to ten core stages and eight Exploration Upper Stagesfor the SLS 1B to transfer heavy payloads, up to 40 metric tons, on a lunar trajectory.
The Space Launch System (SLS) is a US super heavy-lift expendable launch vehicle, which has been under development since its announcement in 2011.
The main launch vehicle planned to be used for the Artemis lunar program, as of May 2020 is the US Space Launch System (SLS). NASA is required to utilize SLS Block 1 by the US Congress to lift a payload of 95 metric tons (209,000 lb) to low Earth orbit (LEO), and will launch Artemis 1, 2, and 3. The later Block 1B is intended to debut the Exploration Upper Stage and launch the notional Artemis 4-7. Block 2 is planned to replace the initial Shuttle-derived boosters with advanced boosters and would have a LEO capability of more than 150 metric tons (330,000 lb), again as required by Congress. Block 2 is intended to enable crewed launches to Mars. The SLS will launch the Orion spacecraft and use the ground operations capabilities and launch facilities at NASA's Kennedy Space Center in Florida. Some variations of the SLS launch manifest has all the blocks being active at the same time rather than one block replacing the last as is common with launchers.
In March 2019, the Trump Administration released its Fiscal Year 2020 Budget Request for NASA. This budget did not initially include any money for the Block 1B and Block 2 variants of SLS but later a request for a budget increase of 1.6 billion dollars towards SLS, Orion, and crewed landers was made. Block 1B is currently intended to debut on Artemis 4 and will be used mainly for co-manifested crew transfers and logistics rather than constructing the Gateway as initially planned. An uncrewed Block was planned to launch the Lunar Surface Asset in 2028, the first lunar outpost of the Artemis program, but now that launch has been moved to a commercial launcher. Block 2 development will most likely start in the late 2020s after NASA is regularly visiting the lunar surface and shifts focus towards Mars.
In October 2019, it was announced NASA had authorized Boeing to purchase materials in bulk for more SLS rockets ahead of the announcement of a new contract. This contract is expected to support up to ten core stages and eight Exploration Upper Stagesfor the SLS 1B to transfer heavy payloads, up to 40 metric tons, on a lunar trajectory.
Artemis program