For more than half a century, the boundary of human exploration remained fixed at low-Earth orbit. Although the International Space Station became a triumph of permanent residency in the void, the deep-space trek to the Moon remained a relic of a bygone era. That is about to change with the Artemis II mission, which will carry four astronauts back into the lunar neighborhood, marking the first time humans have ventured beyond our immediate orbital backyard since the Apollo era.
The journey represents more than just a return to a familiar destination; it is a study in the evolution of engineering. The crew’s home for the mission—the Orion spacecraft—is roughly the size of two large SUVs, a compact but highly sophisticated vessel that reflects decades of lessons learned. While the objective remains the same as it was in the 1960s, the differences between Apollo and Artemis missions reveal a fascinating tension between cutting-edge innovation and the pragmatic reuse of proven technology.
In many ways, the path to the Moon is still paved with the discoveries of the mid-century. From the chemical composition of the fuel to the fundamental physics of the launch, NASA is finding that some solutions were so definitive that they simply do not need upgrading.
The Architecture of Power: Recycling the Shuttle
To the casual observer, the Space Launch System (SLS) looks like a spiritual successor to the Saturn V, the towering 111-meter behemoth that powered the Apollo missions. Yet, the SLS is less a new invention and more a masterclass in aerospace recycling. While the Saturn V relied on a single massive main engine for its initial ascent, the Artemis architecture utilizes a hybrid approach: one main core stage flanked by two powerful booster rockets.
Remarkably, the SLS is built using components that have already seen the vacuum of space. The booster rocket casings and the four main engines at the base of the rocket are repurposed from the Space Shuttle program. By utilizing these flight-proven engines, NASA has bypassed the risks associated with entirely new propulsion systems while maintaining the raw power necessary to escape Earth’s gravity.
The Vehicle Assembly Building has barely changed since the Saturn V rocket for Apollo 14 (left) to Artemis I. (Supplied: NASA/Aubrey Gemignani)
This pragmatism extends to the fuel itself. Despite seventy years of research into exotic chemical combinations, NASA continues to rely on a mixture of liquid hydrogen and liquid oxygen. As Adam Gilmour, CEO of Gilmour Space Technologies, notes, the core concepts of rocketry haven’t fundamentally shifted given that the performance of hydrogen and oxygen remains the gold standard; there is no “warp-drive” or anti-gravity alternative available to modern science.
From Kilobytes to Command Consoles
If the rockets are a story of continuity, the computers are a story of a digital revolution. The Apollo Guidance Computer was a marvel of its time, allowing astronauts to navigate to the Moon with a mere 74 kilobytes of memory and approximately 4KB of RAM. It was a system that required meticulous hand-coding and, occasionally, manual intervention. During the Apollo 8 mission, astronaut Jim Lovell famously had to utilize an onboard sextant to manually re-enter the spacecraft’s location after incorrect code was entered into the system.
In contrast, the “brain” of the Orion spacecraft—the Command and Data Handling Console—operates on a scale that would be unfathomable to the Apollo crews. Artemis’s computer systems can process data 20,000 times faster than those used in the 1960s and possess 128,000 times more memory. This leap in processing power allows for greater autonomy, as seen during the Artemis I mission, where the craft was piloted largely by software and flight controllers on Earth, with mannequins serving as the only “crew.”
Margaret Hamilton stands next to a pile of flight software she led the development of as part of the Apollo Project. (Wikimedia Commons: Draper Laboratory, Margaret Hamilton, PDM)
Yet, the human element of control remains rooted in history. The Christopher C. Kraft Jr. Mission Control Center in Houston, Texas, has served as the nerve center for lunar exploration since 1965. While the screens have changed from analog monitors to high-definition displays, the radio call sign “Houston” continues to be the lifeline for astronauts in the deep black.
The Human Logistics of Deep Space
Perhaps the most visceral improvement in the transition from Apollo to Artemis is found in the most mundane of requirements: waste management. During the Apollo missions, the “toilet” was essentially non-existent. Astronauts relied on urine collection bags and plastic bags for solid waste—a system that was fraught with difficulty. The hazards of this primitive approach were captured during the Apollo 10 mission, when commander Tom Stafford reported a piece of floating feces in the cabin, urgently requesting a napkin to deal with the anomaly.
Artemis II introduces the Universal Waste Management System, a high-tech evolution based on the designs used on the International Space Station. This system uses suction to manage waste in zero gravity and is designed to accommodate both male and female anatomy, a necessary requirement for NASA’s goal of landing the first woman on the Moon. While even these systems can encounter glitches, the alternative is a return to the “bag method” of the 1960s.
| Feature | Apollo Era | Artemis Era |
|---|---|---|
| Computer Memory | ~74 KB | 128,000x increase |
| Re-entry Speed | ~35,000 km/h | ~40,000 km/h |
| Waste Management | Collection bags | Universal Waste Management System |
| Post-Flight Protocol | 21-day quarantine | No quarantine required |
The Perils of Re-entry
The most dangerous phase of any lunar mission is the return. The Orion spacecraft utilizes a large heat shield made of Avcoat, a re-engineered version of the material used during Apollo. However, the stakes are higher for the Artemis II crew. While Apollo spacecraft re-entered the atmosphere at roughly 35,000 kilometers per hour, Orion will hit the atmosphere at approximately 40,000 km/h—the fastest re-entry ever attempted for a crewed craft.
To mitigate the risks associated with this extreme speed and the potential for heat shield degradation, NASA has adjusted its approach. The “skip-entry” maneuver, which was used during the uncrewed Artemis I mission to bleed off speed, has been replaced for Artemis II with a more direct, steeper re-entry pathway to ensure the craft enters the atmosphere safely and predictably.
The Apollo Command Module used a similar material for the heat shield, but in one large block. (Supplied: NASA)
Once the astronauts splash down, they will avoid one of the most oppressive aspects of the original lunar missions: the quarantine. In 1969, the Apollo 11 crew spent a week in a converted Airstream caravan and subsequent isolation in the Lunar Receiving Laboratory to protect Earth from potential “moon pathogens.” Modern science has largely dispelled the fear of lunar contagions, meaning the Artemis II crew can transition from the capsule to their families without the need for a sterile trailer.
The Apollo 11 astronauts were welcomed back to Earth by President Nixon while still in quarantine, aboard the USS Hornet. (Supplied: NASA)
As NASA prepares for the next phase of the Artemis program, the focus shifts toward the eventual goal of a sustainable lunar presence. The next confirmed milestone will be the final integration tests and crew training for the Artemis II mission, as NASA works toward its target launch window. The success of this mission will pave the way for Artemis III, the first mission intended to return humans to the lunar surface.
Do you reckon the reuse of Space Shuttle parts is a smart move or a limitation of the current program? Share your thoughts in the comments below.
