What Could Go Wrong on Artemis II?

Navigating the Perils

The Artemis II mission represents a monumental step in humanity’s return to the Moon. For the first time in over half a century, astronauts will venture beyond low Earth orbit, piloting the Orion spacecraft on a journey that will loop around the far side of the Moon before returning home. This mission is not a lunar landing; it’s a test flight, a shakedown cruise for the hardware and the people of the Artemis program. Its primary objective is to prove that the Orion capsule and its powerful Space Launch System (SLS) rocket are ready to carry humans safely into deep space.

While the mission promises breathtaking views and invaluable data, it’s also fraught with immense risk. Spaceflight is an unforgiving endeavor, and a mission to the Moon pushes technology and human endurance to their absolute limits. Understanding what can go wrong is not an exercise in pessimism. It’s a way to appreciate the staggering complexity of the mission and the incredible layers of engineering, training, and planning that NASA and its international partners have implemented to protect the four astronauts on board. Every component, every line of code, and every procedure is designed to counter a long list of potential failures. This article explores the challenges and dangers that the Artemis II crew could face at every stage of their historic journey, from the violent moments of liftoff to the final, fiery return through Earth’s atmosphere.

The Launch: A Symphony of Controlled Violence

The journey begins atop the Space Launch System, the most powerful rocket ever constructed. For approximately eight minutes, the crew will be passengers on a vehicle that generates 8.8 million pounds of thrust, accelerating them from a standstill to over 17,000 miles per hour. This phase is a whirlwind of intense vibration, crushing G-forces, and precisely controlled explosions.

A primary concern during ascent is the performance of the SLS rocket’s propulsion systems. The core stage is powered by four RS-25 engines, the same reliable model that powered the Space Shuttle, supplemented by two massive solid rocket boosters. A failure in any of these components could be disastrous. An engine could underperform or shut down prematurely, which might prevent the vehicle from reaching a stable orbit. In a more severe scenario, a catastrophic engine failure or a rupture in a booster casing could lead to an explosion on the launchpad or mid-flight.

To counter this threat, Orion is equipped with a Launch Abort System (LAS). This powerful rocket tower sits atop the crew capsule and is designed to activate in milliseconds. If sensors detect a critical failure with the SLS rocket, the LAS will fire its own motors, pulling the Orion capsule and its crew away from the exploding booster with immense force. It would then orient the capsule for a parachute-assisted landing in the Atlantic Ocean, away from the immediate danger.

Beyond the engines, the structural integrity of the rocket itself is a major consideration. The SLS is a massive structure subjected to incredible aerodynamic pressures and vibrations. A flaw in a weld, a faulty bolt, or unexpected stress could lead to a structural failure, causing the vehicle to break apart. NASA and its contractors, like Boeing, conduct exhaustive testing and analysis, using advanced imaging techniques to inspect every inch of the rocket for potential weaknesses before it ever reaches the launchpad.

The rocket’s brain, its guidance and control system, is another potential point of failure. If the avionics were to malfunction, the SLS could veer off its planned trajectory. An out-of-control rocket of this size poses a significant threat, which is why every launch is monitored by a Range Safety Officer. If the vehicle strays from a predefined safe corridor, the officer has the authority to remotely destroy it to prevent it from endangering populated areas. In such a scenario, the crew’s only chance of survival would again be the Launch Abort System. Redundant flight computers and navigation systems are built into the rocket to make this possibility extremely remote.

Finally, even with a perfect rocket, the weather must cooperate. Launches are prohibited in conditions with high winds, which could push the rocket off course or put too much stress on its structure. Lightning is another major hazard; a lightning strike could disable the rocket’s electronics. The Apollo 12 mission was famously struck by lightning twice shortly after liftoff, temporarily knocking out many of its systems. Today, strict weather criteria, monitored by the 45th Weather Squadron at Cape Canaveral, prevent a launch from occurring if there is any risk of such an event.

In Earth Orbit: The Critical Checkout Phase

Successfully reaching orbit isn’t the end of the first challenge; it’s the beginning of a new one. Once the SLS has done its job, the Orion spacecraft, still attached to the rocket’s upper stage – the Interim Cryogenic Propulsion Stage (ICPS) – will circle the Earth. This phase of the mission is a deliberately cautious pause, a chance for the crew and Mission Control Center in Houston to perform a thorough health check on all of Orion’s systems before committing to the journey to the Moon.

A key task is the deployment of Orion’s four solar arrays. These wing-like panels are Orion’s lifeline, providing the electrical power needed to run its computers, life support, and communications systems. A failure of these arrays to deploy or function correctly would be a mission-ending event. The spacecraft has internal batteries, but they can only sustain the crew for a limited time. If the solar arrays failed, the mission would be immediately aborted, and the crew would use the remaining battery power to perform an emergency de-orbit and return to Earth. The successful deployment and performance of these arrays on the uncrewed Artemis Imission provided a great deal of confidence, but it remains a point of intense focus.

During this checkout period, the crew will test every aspect of their spacecraft. This includes the flight computers, the navigation equipment, the communications gear, and, most importantly, the life support systems. It’s far better to discover a faulty valve or a software bug while a safe return to Earth is just a 90-minute orbital maneuver away than to find it three days into a lunar voyage.

The final major hurdle in this phase is the Trans-Lunar Injection (TLI) burn. This is the moment the ICPS fires its engine for several minutes to accelerate Orion out of Earth’s orbit and onto a trajectory toward the Moon. This engine must perform flawlessly. If it fails to ignite, the mission cannot proceed to the Moon. The crew would be stuck in Earth orbit and would have to return home. If the engine underperforms, delivering less thrust than planned, it could put Orion on a trajectory that either falls short of the Moon or requires significant course corrections later, consuming precious fuel. While an ICPS failure would be a major disappointment, it is not considered a life-threatening scenario, as a safe return from low Earth orbit is a well-practiced procedure.

The Journey to the Moon: Navigating the Void

Once the TLI burn is complete and the ICPS is jettisoned, the Artemis II crew will be truly in deep space, farther from Earth than any human has been since the Apollo era. For the next several days, they will be inside the Orion capsule as it coasts through the vacuum of space. This transit phase introduces a new set of risks that are unique to missions beyond the protective shield of Earth’s magnetic field.

The most significant of these is radiation. Earth’s magnetosphere deflects the vast majority of harmful charged particles streaming from the Sun and from deep space. Once Orion passes through the Van Allen radiation belts, the crew will be exposed to a much harsher radiation environment. The primary concern is an unpredictable solar event, such as a solar flare or a coronal mass ejection (CME). These events can release massive bursts of high-energy particles that could overwhelm the spacecraft’s shielding. Exposure to such an event could cause acute radiation sickness for the crew and significantly increase their lifetime risk of cancer. To mitigate this, Orion’s trajectory is carefully planned, and space weather is constantly monitored by agencies like NOAA’s Space Weather Prediction Center. If a major solar event is detected, the crew can take shelter in a designated area within the capsule, using the bulk of the spacecraft’s equipment and supplies as additional shielding.

Another constant threat is a collision with a micrometeoroid or a piece of orbital debris. Even a particle the size of a grain of sand, traveling at tens of thousands of miles per hour, carries enough kinetic energy to cause serious damage. Orion is protected by a multi-layered shield, known as a Whipple shield, designed to break up and absorb the energy of small impacts. A larger impact could potentially puncture the capsule’s pressurized hull. A small leak might be manageable with onboard repair kits, but a larger breach would cause a rapid depressurization, forcing the crew into their spacesuits and triggering an immediate abort of the mission. A strike on a sensitive component, like a propellant tank, a radiator for the cooling system, or the main engine, could cripple the spacecraft and endanger the crew.

The health of the spacecraft’s European Service Module (ESM) is paramount during this phase. Built by the European Space Agency (ESA) and its contractor Airbus Defence and Space, the ESM is Orion’s powerhouse. It contains the primary propulsion system, fuel tanks, and the solar arrays. The main engine is required for any major course corrections and, most importantly, for the burn that will take Orion out of lunar orbit and set it on a course back to Earth. A complete failure of this engine could leave the crew stranded. As a safeguard, the Artemis II mission is designed to fly on a “free-return trajectory.” This means that after the initial TLI burn, the spacecraft’s path will be shaped by gravity to naturally loop around the Moon and return to the vicinity of Earth without requiring any major engine firings. This provides a important safety net in case of a main engine failure early in the mission.

Finally, the Environmental Control and Life Support System (ECLSS) must function perfectly. This complex network of hardware provides oxygen, scrubs carbon dioxide from the air, manages temperature and humidity, and supplies clean water. Building on decades of experience from the Space Shuttle and the International Space Station (ISS), the system has multiple layers of redundancy. However, a cascading failure in a system like the CO2 scrubbers would be a life-threatening emergency, forcing the crew to abort the mission and race back to Earth before the cabin atmosphere becomes toxic.

The Lunar Flyby: A High-Stakes Slingshot

The centerpiece of the Artemis II mission is its flight path around the Moon. This carefully choreographed maneuver will take the Orion spacecraft closer to the lunar surface before looping it around the far side and slingshotting it back toward Earth. This phase tests Orion’s deep-space navigation and communication capabilities in a dynamic gravitational environment.

Precise navigation is everything. The burns performed by the ESM’s thrusters must be executed with pinpoint accuracy. A miscalculation or an engine that burns for slightly too long or too short a time could send Orion into an incorrect orbit or on a trajectory that deviates from the planned free-return path. While the spacecraft carries enough reserve propellant to correct for minor errors, a significant navigational mistake could require complex and fuel-intensive maneuvers to fix, potentially depleting the fuel needed for a safe return. To ensure they are always on course, the crew and ground controllers will rely on multiple data sources, including sophisticated star trackers on the spacecraft and constant communication with NASA’s Deep Space Network (DSN), a global network of large radio antennas.

A unique feature of this phase is the planned communications blackout. As Orion travels behind the Moon, the Moon itself will block all direct radio signals to and from Earth. For this period, the crew will be completely on their own, out of contact with Mission Control. This is an expected part of the mission plan. The danger is that if a critical system fails during this blackout, the crew will have to diagnose and solve the problem without any assistance from the thousands of engineers on the ground. The astronauts are extensively trained for autonomous operations and have detailed emergency procedures to follow, but an unforeseen problem during this period of isolation would be a true test of their skill and composure.

The Return Journey: A Long Road Home

After successfully looping around the Moon, the crew begins the long, multi-day coast back to Earth. Many of the risks from the outbound journey persist: the threat of radiation from a solar storm, the chance of a micrometeoroid strike, and the potential for a critical system failure aboard Orion. However, the return trip introduces new challenges centered on human endurance and health.

After more than a week in space, the psychological toll of the mission will become a factor. The crew will be living and working in a confined space, millions of miles from home, in a constantly high-stakes environment. NASA’s astronaut selection process includes rigorous psychological screening to select individuals who are resilient and work well in teams. They undergo extensive training to handle stress and conflict. The mission timeline is also carefully structured to include adequate time for rest, private communication with family, and leisure activities to maintain morale. Still, the risk of interpersonal friction or performance degradation due to psychological stress is a real concern on any long-duration spaceflight.

A more acute risk is a medical emergency. While the crew is in peak physical condition before the flight, an unexpected illness like appendicitis or an injury could occur. The Orion spacecraft is equipped with a comprehensive medical kit, and the astronauts are trained in emergency medical procedures. They can also consult with flight surgeons on the ground in real time. However, their capabilities are limited. There is no hospital in deep space, and an evacuation is impossible. A serious medical event would become a life-threatening crisis, with the crew’s survival dependent on the care they can provide for themselves during the days-long trip back to Earth.

Re-entry and Splashdown: The Trial by Fire

The final phase of the Artemis II mission is the most dynamic and one of the most dangerous: re-entry into Earth’s atmosphere. The Orion capsule will approach Earth at a staggering speed of nearly 25,000 miles per hour (Mach 32). It must shed that immense velocity as heat and kinetic energy to slow down enough for a safe parachute landing.

The single most critical piece of equipment during this phase is the heat shield. This is the largest ablative heat shield ever built, designed to withstand temperatures approaching 5,000°F (2,760°C). As the capsule plows into the atmosphere, the material on the shield, called Avcoat, is designed to char and burn away, carrying the intense heat of re-entry with it. Any damage to this shield, perhaps from a micrometeoroid impact on the return journey, could create a hot spot where superheated plasma could burn through the capsule’s structure. Such a failure would be catastrophic and unsurvivable, similar to the fate of the Space Shuttle Columbia disaster. The performance of the heat shield during the uncrewed Artemis I mission was a major success, but it remains a component that must perform with absolute perfection.

The angle at which Orion enters the atmosphere is also essential for survival. If the angle is too steep, the G-forces and heat load would exceed the structural limits of the capsule and the physiological limits of the crew. If the angle is too shallow, the capsule will act like a skipping stone, bouncing off the upper atmosphere and back into space with insufficient fuel to attempt another re-entry. To manage this, Artemis II will perform a “skip entry.” The capsule will dip into the upper atmosphere to bleed off some speed, then briefly exit the atmosphere before re-entering for its final descent. This technique helps to manage the heat load and also allows for a more precise landing target. It is a complex maneuver that relies entirely on the precision of Orion’s guidance and navigation systems.

Once the capsule has slowed to subsonic speeds, a complex sequence of parachutes must deploy perfectly. A series of smaller drogue chutes will deploy first to stabilize and orient the capsule, followed by three enormous main parachutes that slow the vehicle to a relatively gentle splashdown speed of about 20 miles per hour. A failure of the main parachutes to deploy correctly would result in the capsule hitting the ocean at a velocity that would be unsurvivable for the crew. The parachute system has been extensively tested, but its deployment remains one of the most mechanically complex and tense moments of the mission.

The mission isn’t over at splashdown. The capsule must remain watertight and upright in the ocean. The U.S. Navy recovery teams must then safely reach the crew and retrieve the capsule. Rough seas could delay recovery, leaving the astronauts bobbing in the ocean for an extended period. There’s also a risk of residual toxic propellant fumes leaking into the cabin after landing. The crew must remain vigilant until they are safely aboard the recovery ship.

Human and Ground Systems: The Unseen Risks

Beyond the hardware of the rocket and spacecraft, there are risks associated with the vast network of people and computer systems on the ground that support the mission.

Mission Control Center at the Johnson Space Center is the nerve center of the operation. A major failure here, such as a prolonged power outage, a critical software failure, or a breakdown in communications, could leave the flight crew without the data and guidance they need to make informed decisions. NASA has multiple layers of redundancy for its ground systems, including backup power generators and alternate control centers, to mitigate this risk.

Human error remains a persistent risk in any complex system. A mistake made by an engineer, a flight controller, or one of the astronauts themselves could have severe consequences. The Apollo 13 accident, while ultimately a story of incredible recovery, was initiated by a chain of events that included errors made during pre-flight testing on the ground. To combat this, NASA relies on a culture of rigor and communication. Checklists, simulations, and procedures that require multiple people to confirm a critical command are all designed to catch and correct human errors before they can cause a problem.

In the modern era, cybersecurity is an emerging concern. While highly unlikely, a malicious attempt to hack into NASA’s communication networks or control systems could pose a threat. The mission’s data streams are heavily encrypted, and the flight control systems are isolated from public networks to protect against such an attack.

Summary

The Artemis II mission is a bold and necessary step toward establishing a sustained human presence on the Moon and, eventually, Mars. It is also an undertaking of immense difficulty and danger. The risks are present in every moment of the ten-day flight, from the controlled explosion of launch to the fiery plunge through the atmosphere. The potential points of failure are numerous, involving everything from rocket engines and heat shields to software code and human psychology.

This exploration of what can go wrong is not intended to cast doubt on the mission’s success. On the contrary, it serves to illuminate the incredible challenge that the men and women of NASA and its partner agencies and companies have taken on. Every risk described here has been analyzed, and every system has been designed with redundancies and safeguards to prevent it from occurring. The astronauts’ exhaustive training prepares them to handle emergencies with skill and calm. The Artemis II mission is a test flight in the truest sense; its purpose is to push the boundaries, uncover weaknesses, and prove that the hardware is ready for the even greater challenges that lie ahead. The success of the mission will be a testament to the decades of planning and ingenuity dedicated to overcoming the significant perils of deep-space exploration.

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