Nasa's giant SLS rocket: a guide - Yahoo News

Nasa has been developing a huge rocket called the Space Launch System (SLS) to launch astronauts to the Moon - and eventually Mars.

But the Moon is nearly 1,000 times further than the ISS; getting astronauts there requires a monster rocket.

Nasa Moon rocket core leaves for testing.

The first version of the SLS will be called Block 1.

The Block 1 SLS will tower 23 storeys above the launch pad - making it taller than the Statue of Liberty?

The rocket will launch astronauts in Nasa's next-generation crew vehicle - Orion, boosting it to the speeds necessary to break out of low-Earth orbit and travel onwards to the Moon.

The SLS consists of a giant core stage flanked by two solid rocket boosters (SRBs).

The steam exits engine nozzles at speeds of 16,000 km/h (10,000 mph) to generate thrust - the force that propels a rocket through the air.

If we use thrust as a measure, the SLS will be the most powerful rocket ever when it flies to space in 2021.

The Block 1 SLS will generate 8.8 million pounds (39.1 Meganewtons) of thrust at launch, 15% more than the Saturn V.

In the 1960s, the Soviet Union built a rocket called the N1, in a bid to reach the Moon.

A future version of the SLS - called Block 2 cargo - should approach the N1's thrust levels.

The rocket will stand 98m (322ft) tall in its initial, or Block 1, configuration.

A future version of the SLS, called Block 2 Cargo, will launch 46 tonnes (101,400 pounds) to the Moon.

The SLS will produce 8.8 million pounds (39.1 Meganewtons) of thrust in its Block 1 configuration.

The SLS core stage is based on the space shuttle's foam-covered external tank.

The solid rocket boosters play much the same role in both vehicles.

As an example of these different stresses, in the space shuttle, the RS-25 engines were canted up and away from the solid rocket boosters.

But without significant modifications, no existing boosters have sufficient power to send Orion, astronauts and large cargo to the Moon in one flight - as the SLS would have.