The moment space fans have waited more than 50 years for is almost upon us, as NASA prepares to launch its Artemis II mission to the moon.
But as the space agency counts down to the historic launch, experts have revealed everything that might go wrong.
From a devastating fire on the launch pad to the sudden loss of power mid–flight, the astronauts – Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen – must be prepared for every eventuality.
While NASA has previously demonstrated that the mission is possible with the uncrewed Artemis I flight, adding a human crew brings entirely new risks.
To keep the crew safe, Artemis II has been designed to include advanced systems for evacuation and escape at any point in the mission.
At the heart of this strategy is the Launch Abort System (LAS), a 13.4–metre–tall (44 feet) tower strapped to the top of the Orion spacecraft that can pull the crew to safety in milliseconds.
In addition, as we recently found out when NASA dramatically evacuated the ISS due to a medical crisis, even a small health issue could become critical in space.
From a catastrophic fireball on the launchpad to burning up on re–entry, here are the seven worst–case scenarios for the upcoming Artemis II mission.
From a devastating fire on the launch pad to the sudden loss of power mid–flight, the astronauts – Reid Wiseman (bottom), Victor Glover (top), Christina Koch (left), and Jeremy Hansen (right) – must be prepared for every eventuality
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1. Emergency on the launch pad
NASA has identified three possible launch windows for Artemis II in the coming months: From February 6 to February 11, from March 6 to March 11, and from April 1 to April 6.
When that launch day comes, the Artemis II crew will climb aboard their Orion spacecraft, strapped to NASA’s most powerful rocket.
The Space Launch System is a 98–metre (322–foot) behemoth, filled with over two million litres of supercooled liquid hydrogen, chilled to –252°C (–423°F).
Ahead of launch, NASA will conduct one or more ‘wet dress rehearsals’, during which it will practice safely fuelling and emptying the massive rocket.
However, there is always the possibility of an unexpected propellant leak as Artemis II prepares to launch.
NASA says that potential dangers include fire, propellant leaks, structural failure, or critical system malfunctions.
If that were to happen, the crew might have just minutes to escape from the top of the 83–metre–tall (247–foot) launch tower.
The first moment something could go wrong is on the launch platform. If a propellant leak is detected, the crew will need to evacuate via the emergency slide–wire baskets
If possible, the astronauts will climb out of Orion’s hatch and flee the tower via the high–speed ’emergency egress slide–wire baskets’.
The crew will strap themselves into baskets and hurtle down a cable connected to the ground 365 metres (1,200 feet) away in just 30 seconds.
However, if something goes seriously wrong, the crew might not have time to make it into the slide–wire baskets, which is where Orion’s Launch Abort System (LAS) comes in.
The LAS is made up of two parts: the launch abort tower, containing three solid rocket motors, and the fairing assembly containing four protective panels.
If the tower detects that something is going wrong with the launch, the rockets will fire, producing 181,400 kilograms of thrust (400,000 lbs).
This will tear Orion’s crew module away from the rest of the rocket, accelerating to speeds over 100 miles per hour in five seconds.
If Artemis II has to abort while on the ground, the LAS will blast Orion 1,800 metres (6,000 feet) into the air and over a mile away from the launch pad before levelling out.
The parachutes will then deploy, dropping the crew safely down into the Atlantic Ocean, having travelled five to 12 miles (8–19 km) in just three minutes.
The Space Launch System Rocket is a 98–metre (322–foot) behemoth, filled with over two million litres of supercooled liquid hydrogen, chilled to –252°C (–423°F). NASA is prepared to evacuate the rocket at a moment’s notice should something go wrong
2. Failure during ascent
Once the rocket engines start to fire and the SLS starts to lift off the ground, Artemis II will enter one of the most dangerous phases of the whole mission.
Chris Bosquillon, co–chair of the Moon Village Association’s working group for Disruptive Technology & Lunar Governance, told the Daily Mail: ‘During launch and ascent, the SLS large rocket engines, cryogenic fuels, and complex systems must work perfectly.
‘Abort systems exist, but the highest dynamic forces on the crew occur here.’
Mr Bosquillon says that this launch will be riskier than a typical flight to the International Space Station, and about as dangerous as past Apollo missions.
About 90 seconds after take–off, the spacecraft will hit ‘maximum dynamic pressure’ as the combination of acceleration and air resistance puts the maximum strain on the vehicle.
A structural failure at this moment would result in the rocket simply tearing itself apart under the immense forces of launch.
Luckily for the Artemis II crew, the LAS system can still bail them out if something goes wrong.
If something goes wrong during launch, NASA will fire the Launch Abort System rocket on top of the Orion spacecraft, pulling the crew module away from the rocket in milliseconds
According to NASA, escaping the rocket will be much harder at this moment since the LAS needs to pull Orion to safety without being torn apart in the supersonic airflow.
If something goes wrong during launch, the LAS will fire for around four seconds before Orion jettisons the engines and opens its parachute, landing anywhere within a few to a few hundred miles of the launch site.
While this should keep the crew alive, it will not be a comfortable ride as the astronauts could experience forces 15 times the acceleration of gravity, or 15G.
For reference, the maximum force a trained fighter pilot can typically sustain without passing out is 9G, while the average human typically can’t handle more than 6G.
3. Critical systems failure
Part of what makes Artemis II riskier than NASA’s standard missions is that it is testing relatively new technology.
Compared to a spacecraft like the Crew Dragon, which has been used dozens of times, the Orion spacecraft has only been used once, during Artemis I.
‘Orion’s life support and deep–space systems have never been flown with a crew before,’ says Mr Bosquillon.
If the Launch Abort System has to fire during the launch, the astronauts will be catapulted to safety up to 100 miles away as the acceleration causes forces 15 times stronger than gravity. Pictured: The launch of Artemis I in 2022
This creates a risk that one of the critical systems might fail once Orion has already left the atmosphere.
If something goes wrong during the first day, while Orion is still in low–Earth orbit, the crew can simply fire the engines to make an early return to Earth.
But if part of the engines or life–support system were to fail once the trip to the Moon had begun, things would be much more complicated.
The absolute worst–case scenario would involve multiple systems failing, including the propulsion system, leaving Orion unable to alter its course.
Mr Bosquillon says: ‘During the lunar flyby, Artemis II is dependent on onboard systems; contrary to orbital space stations, there is no option for rapid crew rescue.’
To mitigate this issue, NASA will put Orion on what is known as a ‘free return trajectory’.
This means the spacecraft will naturally swing around the moon and be tossed back towards the Earth by lunar gravity, without needing to fire its engines at all.
‘This is the solution that provides a built–in safe return baseline if major propulsion fails,’ says Mr Bosquillon.
If systems fail during flight, Artemis II may have to wait for its trajectory to carry it around the moon and back to Earth. For this reason, Orion (pictured) is stocked with enough food, water, and air to last longer than the 10 expected days
In case of emergency, Orion is stocked with more food, water, and air than is needed for the planned 10 days and contains multiple redundant systems to keep the crew alive long enough to return home.
4. Medical emergencies
Earlier this month, NASA was forced to make the first–ever evacuation of the ISS after a crew member suffered an unspecified medical emergency.
Although the space agency has remained tight–lipped on the details, this shows just how quickly medical issues can spiral into a crisis.
Living outside Earth’s gravitational pull can have devastating effects on the body, causing prolonged periods of nausea, muscle and bone atrophy, and cardiovascular issues.
However, the bigger problem for Artemis II is simply how far the crew will be from health should something go wrong.
Dr Myles Harris, an expert on health risks in remote settings at UCL and founder of Space Health Research, told the Daily Mail: ‘Space is an extreme remote environment, and astronauts react to the stressors of spaceflight differently.
‘It follows that many of the challenges of healthcare in space are similar to the challenges of providing healthcare in remote and rural environments on Earth.’
Artemis II will follow the first–ever medical evacuation of the ISS, showing how health issues in space can quickly become critical. Left to Right: Russian cosmonaut Oleg Platonov, NASA astronauts Mike Fincke and Zena Cardman, and Japanese astronaut Kimiya Yui during the evacuation
Just like an Antarctic expedition here on Earth, the astronauts will have limited medical equipment, unreliable access to expert opinion, and will be days away from the nearest hospital.
If a crew member were to experience a medical problem, these factors mean that small issues can become critical.
5. Heatshield failure
Once Orion has completed its lunar flyby and the return flight to Earth, the crew will still have to face the single most dangerous part of the mission.
As Orion hits Earth’s atmosphere at around 25,000 miles per hour (40,000 km/h), friction will cut that speed to just 300 miles per hour (482 km/h) in just minutes.
The result is an incredible amount of heat, as the front of the spacecraft reaches temperatures of around 2,760°C (5,000°F).
At this point, the only thing standing between the crew and instant destruction will be about four centimetres of thermal–resistant material called the heatshield.
The problem is that some experts and former astronauts don’t believe Orion’s heatshield is up to the task.
The most dangerous moment will occur during re–entry, as Orion’s heatshield is subjected to enormous temperatures due to friction with the atmosphere. Pictured: Orion’s heatshield after re–entry during Artemis I
During the Artemis I test, NASA found that Orion’s heatshield was cracked and cratered with unexpected damage.
The heatshield material, known as Avcoat, is designed to burn away during re–entry to help dissipate the heat, but this damage was well beyond what NASA had expected.
While the heat shield didn’t fail, and the crew would have been safe, the heatshield wasn’t performing as NASA had expected.
Following the mission, Dr Danny Olivas, a former NASA astronaut who served on a space agency–appointed independent review team that investigated the incident, told CNN: ‘There’s no doubt about it: This is not the heat shield that NASA would want to give its astronauts.’
The problem was that the Avcoat layer wasn’t permeable enough, so gases built up in pockets and blasted off entire chunks.
NASA has decided not to change the heatshield going into Artemis II, but has made some important changes to the mission.
Mr Bosquillon says: ‘NASA decided to adjust the Artemis II re–entry trajectory so as to reduce the time spent in extreme speed and thermal conditions that triggered the issue.’
Artemis II will make a ‘skipping’ re–entry as it returns to Earth, meaning it acts like a stone bouncing on water as it dips and lowers itself into the atmosphere.
The heatshield coating is designed to burn away during re–entry, however, NASA found that the coating had chipped and deteriorated far more than expected during Artemis I
NASA has not altered the heatshield for Artemis II, but has adjusted the trajectory so that Orion will spend less time at critical temperatures
This helps the craft spread out the heat caused by decelerating and target a precise splashdown area.
With the new tractor, the craft won’t bounce as high on each skip and will just loft slightly.
NASA says this is intended to create ‘a steeper descent angle to reduce exposure time at peak heating, thus minimising further char loss.’
If NASA’s modelling proves correct, this should ensure that the Avcoat keeps the crew safe, without switching to an untested heatshield technology
‘NASA identified the root cause, updated its models, and adjusted operations to preserve crew safety without rushing to redesign, which in fact would have been a major risk factor since largely untested,’ says Mr Bosquillon.
