Part II of III: Counting Down to Takeoff, Meet Artemis SLS

This is the second of a three-part series on the inauguration of the Artemis Lunar and Deep Space Missions using the SLS Rocket, developed and tested here in Huntsville, and set to launch tentatively, by the end of the year from Kennedy Space Flight Center.

Home to the propulsion systems associated with the rockets we currently fly, and every successful rocket we have flown in the past, the Rocket City is once again at the heart of world-changing feats and life and death-defying technology.

Rocket scientists here in Huntsville are already working on hardware for five iterations of the Artemis Space Launch Systems (SLS), America’s next generation exploration class rocket, and the only rocket that can fly the manned Orion spacecraft safety to the moon.

Fifteen percent more power than the Saturn V, the SLS is the only exploration class vehicle capable of sending humans into deep space along with large systems that are necessary to live and work in deep space.

And none of these missions can get off earth and escape earth’s gravity field without the SLS, managed and for a large part, built here in Huntsville!

According to John Honeycutt, program manager for Space Launch Systems, SLS is a foundational asset and key component to deep space architecture that will allow us to journey to Mars and destinations beyond. 

SLS Rocket visual illustration

SLS is a unique super heavy lift vehicle that allows for reduced complexity and risk to everything from payload design to ground infrastructure to in-space operations. 

In a business that talks about risk and weighing probabilities of success, Honeycutt said SLS is way ahead of the game, providing the best opportunity for mission success.

“In 2019, the world celebrated the 50th anniversary of the Apollo 11 moon landing, for which Huntsville had … I guess you could say a small part,” said a cheeky Honeycutt to a recent audience at the National Geographic Theater at the U.S. Space & Rocket Center’s Davidson Center. “In the propulsion community we always let our friends at the manned space flight centers know, they can’t get there without us!” he said to the laughing audience.

“The Apollo and Saturn V programs changed the world, but I am here to tell you that Artemis and Space Launch Systems will change the world too. It will just be a little different this time because the vision is different, and the mission is different.

“When we land Artemis astronauts on the South Pole of the Moon, they will step foot where no other human has stepped before and this time, we are there to stay.” 

It is important to return to the moon for many reasons according to Honeycutt. 

“By putting boots on the moon, we can transfer the knowledge about what we learn to go further out and explore other planets,” he said. “With the horizon goal of sending humans to Mars, Artemis begins the next era of exploration.”

The build up to a sustained lunar presence consists of a series of 21st century firsts.

Honeycutt said they are working very hard towards a successful launch of Artemis I by the end of this year. Artemis I is an unmanned test flight for flying a manned Orion spacecraft on Artemis II in 2023. It will go further than we have ever been in space.  

SLS Block I is a workhorse for the first phase of the Artemis program.

Looking at it being stacked at the Vehicle Assembly Building at Kennedy Space Center, what stands out is how big the rocket is compared to those used on the Space Shuttle.

“This rocket is huge, awe-inspiring and just tremendous,” said Honeycutt. “The core stage is 212 feet tall and holds 700,000 gallons of liquid oxygen and liquid hydrogen used to propel the core stage, using the four RS-25 engines that produce 2.5 million pounds of thrust.”

That accompanies the two most powerful solid rocket boosters in the world, recently tested in New Mexico’s desert. The power of one of the boosters, each having 3.6 million pounds of thrust, provided 75 percent of the thrust needed to escape earth’s gravity field on initial takeoff.

Despite the newness, SLS will surprisingly reuse many of the reliable and proven propulsion systems upgraded from the Space Shuttle program.

“The RS-25 (main shuttle engines) are extremely reliable,” said Honeycutt. “We knew engine development was expensive and time-consuming, so we were fortunate to inherited 16 of them from the Space Shuttle program.

“We’ve done a lot of work to get those engines upgraded properly and we know these engines are extremely reliable. The RS-25s and solid rocket boosters we have, are the safest rocket we can fly.

“Teams here in Huntsville are already working on the exploration upper stage, which will allow us to launch 40 percent more payload than the rocket we are flying on today meaning SLS is going to send America’s most important human exploration and science missions faster and farther than ever before … or should I say, more, farther and faster.”

Fully stacked and integrated, SLS stands 322 feet tall and boasts 8.8 million pounds of thrust – enough to hoist 59,000 pounds in translunar injection. The twin boosters and RS-25 engines make SLS 15 percent more powerful than the Saturn V launch rocket.

The rocket has the power and capacity to lift large complex payloads, reducing the number of operations needed in space and simplifying integration activities. It is much easier, said Honeycutt, to put science missions and payloads together on the ground and deploy them in space, than it is to fly them in small pieces and build them in space. There is a significant amount of risk by doing that and SLS has that capability.

Honeycutt said SLS also allows for a lot of flexibility in the human missions, co-manifested payloads, and cargo type payloads used for scientific missions. 

Artemis II will fly relatively the same mission as Artemis I, but the astronauts will orbit the moon.

Artemis loaded onto Pegasus barge headed from Marshall Space Flight Center to Kennedy

“It will be the first time we have done that since 1972,” said Honeycutt. “We will be able to do a rendezvous on that mission.”

Scheduled for 2024, Artemis III will land the first crewed missions to the lunar surface in the 21st century.

With every mission, SLS will evolve from a system with greater capability than any existing launch vehicle, to a Mars-enabling capability, avoiding the need for a new vehicle design with each iteration.

He said from a biometric perspective, SLS can carry twice the volume of any contemporary launch vehicle including things like habitat modules, refractor telescopes for buzz science packages, robotic probes, and more.

Artemis IV will kick off tremendous activity with the beginning of the Block IB configuration and the USA – the Universal Stage Adapter, offering more volume for payloads, compared to the current industry standard of a 5-meter fairing. 

From a mass perspective, the initial Block I configuration capability is over 100,000 pounds; and from an energy perspective, which is what it takes to escape earth’s gravity field, SLS offers reduced transit time to the outer solar systems and cuts transit time in half or greater.

“We have done some mission analysis that show some missions might take seven to eight years to reach a destination on other rockets, while on SLS, it will take only two or three,” said Honeycutt. “The scientists who developed the experiments spend a long time waiting for their spacecraft to get to their destinations, so we can speed that process up and help them get into the learning phase much faster.”

Several companies, all with a presence in the Huntsville area, are key to bringing Artemis to life. 

Northrup Grumman developed the two 5- segment solid rocket boosters; Aerojet Rocketdyne is responsible for the four RS-25 engines; Boeing oversees the big new core stage; and Teledyne Brown Engineering is responsible for the Launch Vehicle Stage Adapter.

Boeing and United Launch Alliance are providing the interim cryogenic propulsion stage being built in Decatur. The ICPS is a modified Delta 4 upper stage using a workhorse proven RL-10 engine to provide just a little under 25,000 pounds of thrust for the upper stage. The identical twin of Artemis I will be used in Artemis II to send the first astronauts into orbit around the moon since 1972. 

Marshall Space Flight Center is doing an in-house design for the stage adapter. The European Space Agency and Airbus are providing the surface module that powers the Lockheed Martin-built Orion spacecraft.

Hold on tight, Huntsville! To the Moon Alice! 

Photo Credits: NASA; https://www.nasa.gov/exploration/systems/sls/index.html