Understanding the Space Launch System (SLS)

The Space Launch System (SLS) is NASA's next-generation spacecraft. As space exploration becomes more ambitious, there’s a need for rockets that can carry heavier payloads on longer journeys. The SLS is designed to meet these needs and provide the flexibility to handle different missions, such as setting up a permanent base on the Moon and traveling to Mars.

The SLS is a cornerstone of NASA's Artemis program, which will lay the groundwork for the return to the Moon and eventual Mars landings. Its payload capabilities mean it can transport modules for space stations, sustainable habitats, and heavy equipment.

As it continues to develop, the SLS moves closer to making these ambitious goals a reality. Here’s a closer look at NASA's most powerful spacecraft.

What Is the Space Launch System (SLS)?

NASA has partnered with different aerospace companies to develop the SLS. These collaborators include Aerojet Rocketdyne, Boeing, and Northrop Grumman.

The cooperation between NASA and the private sector is a new dynamic that helps the space agency get expertise and drive space travel advancements it wouldn't be able to achieve in-house. These companies contribute components and technologies that NASA can use to build the entire system to its specifications for the upcoming Moon and Mars missions.

The purpose of the SLS is to serve as the primary vehicle for NASA's deep space exploration projects. These include the Artemis program, which will send humans to the Moon and eventually launch crewed missions to Mars.

The rocket's design has these missions in mind. The solid boosters, provided by Northrop Grumman, deliver the thrust needed to escape Earth's gravity, and Aerojet Rocketdyne's RS-25 engines use liquid hydrogen and oxygen fuel to power the core stage. Finally, the small upper stage allows for efficient travel in deep space.

Here’s a closer look at the rocket’s different components and the roles each plays.

Core Stage

The core stage of the SLS is the largest and most muscular part of the craft. It stands at 212 feet tall and has large fuel tanks that hold a combined 733,000 gallons of liquid hydrogen and oxygen. These tanks supply four rockets that produce 500 seconds of power to take the ship out of the Earth's atmosphere.

The core stage also has avionics systems to guide the rocket through the atmosphere. These help ensure control during the most intense phase of space flight.

Boosters

The solid rocket boosters of the SLS are the most powerful ever built. They provide over 75% of the thrust required during the first two minutes of flight. Each booster is 177 feet tall and contains more than 1.6 million pounds of fuel, which burns at an incredible rate of six tons per second.

This amount of power is necessary to break the Earth's gravitational pull. The boosters work together with the core stage to get the SLS past the atmosphere and into orbit.

The boosters also provide an example of the practical elements of the SLS's design.

The booster's steel casing can be reused from previous launches, lowering the cost of each mission.

RS-25 Engines

The RS-25 engines are based on the original Space Shuttle program rockets. They’ve already stood the test of time, powering spacecraft on 135 missions over the past three decades. Upgrades during the previous decade gave the engines slightly more power, allowing them to run up to 113% of their rated thrust levels.

These engines are designed to operate at extreme temperatures and produce enough power to help take the massive SLS into orbit. The RS-25s burn liquid hydrogen and oxygen to produce 500,000 pounds of thrust each.

In the SLS, the RS-25s sit at the base of the core stage. Current tests use a four-rocket setup.

Upper Stage

The upper stage takes over once the SLS reaches space, and the core stage and boosters have done their job. Currently, the plan is to use an Interim Cryogenic Propulsion Stage (ICPS) with a single RL10 engine for uncrewed flights.

However, for the longer, more involved Artemis missions, NASA and Boeing are developing the Exploration Upper Stage (EUS). This four-RL10-engine upper stage can travel further and handle larger payloads for in-depth Moon missions and an eventual trip to Mars. The stage can operate with three engines, making it possible to travel even if there’s been a malfunction.

How Will SLS Contribute to NASA Launch and Future Space Missions?

SLS is central to NASA's Artemis program, which will include trips to the Moon and future missions to Mars.

There’s already a framework for the first missions. Artemis I will be an uncrewed test flight, and Artemis II will carry astronauts around the Moon. These missions will set the stage for Artemis III, the first lunar landing by astronauts since Apollo.

These missions will establish a presence on the Moon and also test the technologies needed for long-duration space travel to Mars.

Beyond the Artemis program, the SLS will eventually be able to support other deep space missions, including to asteroids and the moons of Jupiter. The rocket's lifting capacity means it can carry heavy equipment like space probes that could potentially reach the farthest corners of our galaxy.

The SLS continues to evolve with research and tests giving it capabilities beyond those of first-generation spacecraft like the Saturn V. This development is crucial for NASA's long-term goal of sending humans to Mars and eventually making it habitable.

Challenges and Solutions of Space Shuttle Launch

SLS has developed despite challenges. There have been questions about which aspects of the program need funding and disagreements about cost reduction and budgeting. The government has also criticized the lack of transparency in spending.

Additionally, the SLS project has suffered from technical and quality control issues as NASA and its private partners try to balance cutting-edge technology with safety. That’s on top of scaling up the spacecraft to the size and capability necessary for Artemis and deep space exploration efforts. Addressing these technical obstacles is tedious, with strict testing protocols necessary to ensure changes and fixes can stand up to the harsh environments in space.

Different perspectives, including those offered by female scientists and technical experts from different backgrounds, help provide unique perspectives that have led to innovative solutions.

The SLS represents the most significant leap in space exploration since the Apollo missions to the Moon. The technology currently in development will help NASA launch missions back to the Moon, to Mars, and to other planets and moons beyond. Once fully developed, the spacecraft will be the cornerstone of NASA's missions.