NASA Space Launch System (SLS) is a multi-purpose
heavy-lift launch vehicle system designed to carry astronauts to
an asteroid, moon, mars and beyond. The launch date of the first
flight is 17 December, 2017.

Space Launch Program
The Space Launch System (SLS) Program is developing a heavy-lift launch vehicle
system. These
launch vehicles will be capable of lifting:
- Orion Multi-Purpose Crew Vehicle to ISS
- Cargo, equipment and science experiments to Earth's orbit
- Orion MPCV and cargo to near-Earth asteroids, to cis-lunar space, the moon,
Lagrange points, to Mars and its moons, and to other destinations in the solar
system and beyond.
- Backup launch system for supplying and supporting the International Space
Station cargo and crew requirements not met by other available launch vehicles.
- launching spacecraft to return samples from planets, moons.
Specs:
Core Stage Height: 61 m (200 ft)
Core Diameter 8.4m (27.5 ft)
The Space Launch Vehicle architecture was chosen because:
(1). NASA can leverage existing capabilities and lower
development costs by using liquid hydrogen and liquid oxygen (lox) for both the core
and upper stages.
(2). A modular launch
vehicle that can be configured for specific mission needs using a variation of
common elements - a different
core stage, upper stage and first stage booster combinations to achieve the
most efficient launch vehicle for the desired mission.
(3). It uses an
evolvable development approach, which allows NASA to address high-cost
development activities early on in the program and take advantage of higher
buying power before inflation erodes the available funding of a fixed budget.

Space Shuttle Program and Constellation Program Connection
The SLS rocket will incorporate technological investments from the Space Shuttle
Program and the Constellation Program in order to take advantage of proven
hardware and tooling and manufacturing technology that will
significantly reduce development and operations costs. It will use a liquid
hydrogen and liquid oxygen propulsion system, which will include the RS-25D/E
rocket engines from the Space Shuttle Program for the core stage and the J-2X engine for the
upper stage. SLS will use solid rocket boosters (Ares Project solids) for the initial development
flights, while follow-on boosters will be competed based on performance
requirements and affordability considerations.
The Space Launch System will be evolvable, ultimately carrying 130 metric tons
of crew and cargo to low Earth orbit.

Core Stage
The SLS core stage will store liquid hydrogen (LH) and liquid oxygen (LOX) to
feed the rocket's four RS-25 engines. The RS-25 engines are former space shuttle
main engines for the first few flights. The SLS Program has an inventory of 16
RS-25 flight engines that were used during the Space Shuttle Program. SLS like
the Space Shuttle will be powered initially by two solid rocket boosters on the
sides of the launch vehicle.
Boeing is the prime contractor for the SLS core stage, including its avionics.
The SLS will have an initial lift
capacity of 70 metric tons (154,000 pounds), roughly
the weight of 40 sport utility vehicles. The lift capacity will be evolvable to
130 metric tons - more than 143 tons (286,000 pounds) enough to lift 75 SUVs.
The first test flight of NASA's Space Launch System is scheduled for launch in
17 December 2017. It will feature a configuration for a 77 ton lift capacity.
Upper Stage
The SLS will use various configurations for the upper stages:
Block 0 – No upper stage.
Block I – A Delta Cryogenic Second Stage (DCSS), referred to as the
Interim Cryogenic Propulsion Stage (iCPS). This 70-metric ton configuration
currently will only fly two missions: Exploration Mission 1 (EM-1) and
Exploration Mission 2 (EM-2).
Block IA – A large Cryogenic Propulsion Stage, specifically developed for
SLS and powered by liquid hydrogen fuel and liquid oxygen oxidizer. This
105-metric ton rocket will first launch as SLS-3.
Block IB - CPS consisting of four RL10A-4-2 engines with a 8.4 m fairing
and 105 mt to LEO.
Block II – A fully-fledged Earth Departure Stage to be powered by three
J-2X engines for 130-metric ton rocket.
Missions:
Possible launch dates:
| Mission
|
Variant
|
Launch Date
|
Purpose
|
|
SLS-1/EM-1
|
Block I
|
17 December 2017 |
Send Orion/MPCV on unmanned trip around the Moon. |
|
SLS-2/EM-2 |
Block I |
2021 |
Send Orion MPCV with four members into lunar orbit. |
|
SLS-3 |
Block IA |
2022 |
|
|
SLS-4 |
Block IA |
2023 |
|
|
SLS-5 |
Block II |
2024 |
First launch of SLS Cargo configuration, first flight with
RS-25E engines. |
|
SLS-6 |
Block II |
2025 |
Manned Exploration Mission to Nearest Earth Asteroid ??? |
|
SLS-7 |
Block II |
2026 |
Cargo launch to
Lunar Orbiting Space Station ??? |
|
SLS-8 |
Block II |
2027 |
First launch of
Manned Flyby Mission to Venus Orbit??? |
History
The Space Launch System is NASA's first exploration-class vehicle since the
Saturn V took American astronauts to the moon in the late 1960s and early 1970s.
NASA's Space Launch System (SLS) was authorized by USA's Congress after the
cancellation of the Ares rockets of the Constellation program. The rocket
will be larger than the famous Saturn V moon rocket in the Block 2
configuration.
NASA announced on 24 May 2011 that development of the Orion spacecraft from the
Constellation program will continue as the Multi-Purpose Crew Vehicle (MPCV).
The Delta IV DCSS (Delta Cryogenic Second Stage) was selected in May 2012.