Safety Defined

I found myself saying the words: “the fundamentals remain the same”. A nice phrase that promotes the idea that there are some bedrock ideas that are immune from the winds of change. It’s as easy as saying that 2 plus 2 will always equal 4. Except I wasn’t taking about a mathematical relationship. A traditional set of rules that are so established that it becomes incredibly difficult to think differently. That is unless I get terribly esoteric and argumentative about what do we mean by plus and equals.

Safety is freedom from harm. That’s one of the simplest definitions of “safety”. Simplicity has merit but there’s one or two weaknesses in that basic definition. Although, it’s one that I’m happy to use. It communicates well. Theres a lot to be said for brevity.

The human condition is such that we are never ever free from potential harm. Such is the sheer complexity of our situation that the combinations and permutations of stuff that can harm us is immense. Every tiny cell in our bodies is doing something that it needs to get right. Yet, we exist relatively healthily with a myriad of flaws. Unfortunately, or fortunately, our awareness of the flaws that can harm us is often non-existent. Perhaps we have the freedom of ignorance.

Safety is freedom from harm with these caveats. Generally, even invoking the word “safety” implies that the stuff that can harm us is substantial and tangible. It’s something we might know and understand. Likewise, the word “harm” in this context doesn’t mean trivial or non-consequential actions. It’s something undesirable where effort would be made to avoid.

To compound my kicking away at what seems like a perfectly reasonable simple definition, the well-known dictionaries who publish their wisdom each have different variations on a theme.

Each definition has at least two parts for the abstract noun “safety”. Yes, it doesn’t have a physical form, in of itself but “safety” is a condition. The negative stuff to be avoided comes up as harm, danger, hurt, damage, injury, death, loss, and even risk. The act of avoidance of a negative outcome comes up as a condition of being free or protected.

Another dimension not explicitly mentioned in the common definitions is the dynamic nature of safety. It is not a static condition. Theoretically, the transition from a safe to an unsafe condition can take an infinite number of paths. In reality, some pathways are more probable than others.

This is where the discussion moves away from grammar to the substantial experience of safety. It’s locked into our thinking, and not often expressed that the dynamic nature of the subject means that probabilities always come to bare.

Today, I may not be the least bit concerned that a meteor would crash through the roof of my house without warning and injure me. That is even if I am not entirely free of the possibility of such an event happening. I will take the possibility of tripping on a loose stair carpet much more seriously. Both safety jeopardising events are possible but one is more probable than the other.

Next, I come to what’s conceivable and what’s not. In a universe of an infinite number of possibilities there are lots that are just plain inconceivable. The meteor case above is conceivable. Governments take practical actions to monitor space rocks.

Even to speak of something that is inconceivable is stretching the boundaries of our imaginations. It’s often taken as obvious that certain threats are out of bounds. Yet, the inconceivable occasionally happens and our boundaries are thus expanded. A pilot chooses to fly a perfectly airworthy aircraft into a mountain. As we know it has happened.

I’ll stop here. What’s clear is that a simple definition isn’t simple at all.

Navigating Heights

If I were to explain, the reasoning would go like this. It’s good to have a vivid imagination. As an engineer, it’s essential to be able to create a mental picture of what’s happening. But there’s a downside. Looking at a situation and seeing more than is there, opens the door to imagining all sorts of scenarios that are unlikely.

I’m talking about that experience of peering over a cliff edge to see what’s there. Curiosity being a strong urge. Then pulling back in fright of falling. Often when the ground is solid and safe. Often when nothing more than a spark in the imagination creates an unreasonable fear of falling. The fleeting image I have in mind is looking down at Beachy Head Lighthouse[1].

I have a curious relationship with hights. No, I’m not terrified of heights. It’s just that now and then that fear of falling does kick in. This feeling could be embedded or learnt from an early age. My mother tells a story of me as a toddler being halfway up a ladder. Sacring her. Me being oblivious to any danger and coming to no harm. Growing up on a family farm there was innumerable hazards around every corner.

One of the riskier things was to climb up the haybarn roof. This was an open steel framed structure spanning several bays. Corrugated sheets made up its roof. In the UK, we call these buildings a Dutch barn. This mostly refers to the curved shape of the roof. From the top of the barn, it was possible to see the whole farmyard.

Last week, I hiked around the Caldera de Taburiente on La Palma. I learnt that the term caldera has Spanish origins. So, I was in the right place to assess any fear of hights that might linger in my psyche. The Caldera de Taburiente is more than 2000 m deep.

Even the roughly hewn paths, some restored from local landslides, didn’t phase me. It’s as if, because I was one of thousands who have passed the same way, the dangers where contained. In fact, there were not. Some of the well-worn slippery stones underfoot had to be approached with a great deal of caution. Loose rocks and sheer drops had to be navigated with care.

The Caldera de Taburiente National Park is a magical place. It has a Jurassic Park feel about the place. Given that it’s not much more than a few million years old the place is far to youthful for dinosaurs. It has its own special natural beauty.

My aging but persisting vivid imagination had plenty to occupy itself as we climbed and descended in and out of the park. The whole hike was about 16 km. This was the second time I’d taken this circular route. What surprised me was the hard parts of the climb and decent following a riverbed on the way out. That part I’d conveniently forgotten.

No, I’m not terrified of heights when there’s solid ground underfoot. They do however have the capacity to scare or at least summon up a lot of extra care. I hope that inbuild sense of self-preservation never fails me.


[1] https://www.beachyheadlighthouse.co.uk/

Ethics of Medication

I don’t know about you but the whole idea of medicating people to increase the prosperity of society has a terrible echo of the worst kind of politics. Now, if we change the “p” word to protection of society, a policy of medication might make some reasonable sense. The COVID pandemic taught use that individual freedoms are not absolute. We know that allowing people to spread infection, whenever their personal beliefs, can kill other people. Reckless actions did exposed people to danger. Big name politicians did some dam stupid stuff just because they wanted to side with those who believed irrational, unscientific nonsense.

A UK Labour Health Minister saying that obese people would benefit from a jab so that they can get back to work makes me feel uneasy. It’s one thing to recognise that society has a problem with obesity but it’s entity another for the States to impose medication on specific groups of citizens. Expensive new medication that that.

I know it can be argued that the cost of obesity to the National Health Service (NHS) is high so there’s no zero cost answer. Having hammered down smoking deaths over decades of work it’s now obesity that’s the great societal challenge. The line between personal freedoms and social demands can be a fuzzy one.

The jab in question may have become fashionable as a weight loss aid[1]. That doesn’t justify a UK Minister, with all the power of the State, suggesting that overweight people be put on a regime of injections. And if they say “no” to the regime then be penalised in some vague manner.

It’s known that these new weight loss drugs have side effects. No everyone can take them without consequences. These drugs should only be used under medical supervision. That said, many people do take them without recourse to advice from a doctor.

To the Minister I say, don’t ague about the cost to the economy of obese people. Please ague for helping people to make weight management work for them as individuals. Obese people are not one amorphous mass of idle slobs who sit on the sofa all day. The Daily Mail characterisation of bludgeoning swarms of people burdening society with their indolent ways may chime with populists and the emerging Conservative Party. It’s no way for a Labour Minister to address a live challenge. 

National proposals to give unemployed obese people a jab to get them back to work has a ghastly ring to it. Yes, it’s not saying we (society) should send them down the salt mines but when the economic argument is the top one it does dehumanise the target audience.

Weight loss jabs may continue to have potential befits for many people. Let’s say that we are talking about health benefits, so that individuals can play their role in our society, whatever that role might be. State officials who attempt bring shame on people living with obesity, that’s just plain nasty.


[1] https://www.bbc.co.uk/news/articles/c981044pgvyo

Fatal Aircraft Accident Investigation – Update

Given the tragic nature of VoePass Linhas Aéreas flight PTB2283, it is a fatal aircraft accident investigation of global importance. The Brazilian Aeronautical Accidents Investigation and Prevention Center (CENIPA) is investigating. CENIPA investigations are based on the international standard, namely ICAO Annex 13.

Both the Cockpit Voice Recorder (CVR) and the Flight Data Recorder (FDR) of the civil aircraft, registered PS-VPB, have been successfully replayed[1]. This is a task that required great care and diligence. The replay data now available to the investigators for detailed analysis, is of the utmost significance.

From the pictures available the external impact damage to the flight recorders is evident. What is important is that the crash protected memory module works as intended. This is solid-state digital memory that is packaged in a way that protects it from extreme conditions.

Finding from this accident investigation could have implications for the whole ATR aircraft fleet worldwide. It’s certain the authorities in Brazil will notify the aviation community if findings indicate corrective action that needs to be immediately taken.

Reports in the public domain indicate that the ATR aircraft had an ice detection system and that alerts could be heard in the cockpit during the flight[2]. Additionally, there is the indication that the crew acted in relation to those cockpit alerts.

[My apologies for a post where I suggested that there may not have been an ice detection sensor and alert on this class of turboprop aircraft. I was in error.].

This chain of events may suggest a simple set of explanations for the loss of control of the aircraft as it approached its destination. However, these matters are never simple, as most catastrophic aviation accidents are a combination of factors.

Even though the crew noted that there was icing, there is, as yet, no indication that the atmospheric conditions experienced by the aircraft in-flight were of a truly exceptional nature. The ATR aircraft is certified for specific icing conditions. There is training and procedures for the encounter of icing conditions.

It is pure speculation on my part, but I am reminded of an aviation accident of more than 40-years ago[3]. The conditions of the accident are different, but a factor may link the two. The last line of the NTSB report abstract says: “and the limited experience of the flight crew in jet transport winter conditions.” A small amount of ice contamination in the wrong place at the wrong time can have much more impact that might be immediately assumed.


[1] https://www2.fab.mil.br/cenipa/index.php/ultimas-noticias/1766-cenipa-extrai-com-exito-dados-dos-gravadores-de-voo-da-aeronave-ps-vpb

[2] https://www.flightglobal.com/safety/voepass-atr-crash-probe-analyses-crews-response-to-ice-alerts-before-fatal-flat-spin/159888.article

[3] https://www.ntsb.gov/news/press-releases/Pages/mr20220112b.aspx

Brazilian Air Crash

Two weeks have elapsed since the tragic loss of VoePass Linhas Aéreas flight PTB2283[1].

Reports are that the Brazilian air accident investigators[2] have successfully downloaded recordings from the aircraft Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR).

A detailed analysis of both recordings should provide a replay of the flight events on the fateful day. This means that any flight anomalies can be interpreted. Both actions of the crew and the response of the aircraft can be used to understand the sequence of events.

Those conducting the analysis will need to verify the past serviceability[3] of both recorders. It’s easy to assume that what’s presented in the recovered replay is what happened. However, that depends on the calibration of sensors and the correct functioning of the aircraft’s audio system.

CVRs and FDRs are primarily tools for the investigation of accidents and serious incidents by investigating authorities. Accident recordings can be a rich source of information. It’s not just the obvious contribution technical records make to an investigation. The CVR, via a cockpit area microphone picks up much more than just the speech of the crew and their communications with air traffic. Engines, propellers, aircraft warning systems, aerodynamic noise and the impact of structural failures all produce audio signatures.

I assume that the aircraft operator has a Flight Data Monitoring Program. Such a program can support continuing airworthiness and operational safety of an aircraft. It can be a vital part of a Safety Management System (SMS). Also, the regular analysis of flight data is one way of ensuring that the serviceability of the data acquisition system for an FDR is known.

A preliminary report on this fatal accident is expected in early September. It is up to CENIPA if the publish any transcript of the accident recordings.

VoePass, the airline in question, operates a regional network in Brazil. Not surprisingly it has now come under greater scrutiny by the Brazilian aviation regulator, Agência Nacional de Aviação Civil (ANAC).

It’s worth noting that the Brazilian civil aircraft fleet is one of the largest in the world. It’s a sizable country. Both ANAC and CENIPA are well experienced in addressing the aftermath of a major aviation accident. Expectations are high that the causes of this fatal accident will be fully understood. Appropriately then corrective action will be taken.


[1] https://asn.flightsafety.org/wikibase/409335

[2] Brazilian Aeronautical Accidents Investigation and Prevention Center (CENIPA)

[3] https://www.caa.co.uk/publication/download/12811

Navigating Speculation in the Age of Abundant Information

Speculation is a natural human response. When faced with a paucity of information we often put together what we know and then make a best guess as to what happened or what might happen. However, wise or unwise it’s not possible to stop speculation. Well, that is assuming that autocratic power doesn’t use force to crush the free exchange of ideas.

Since the rise of the INTERNET, with a proliferation of all kinds of material, it becomes less and less possible to quell speculation. A sprinkling of information can grow into a monstrous conspiracy but equally it can grow into a stepping stone to greater understanding. Living with this two-edged sword is our modern dilemma.

In a more deferential society, that we may have been immediately post WWII, officialdom was accustomed to restricting information. The principal of “need to know” and statements like – wait for the official report – were enough to quell Press intrusion and intense public curiosity. On occasions this deference turned out to be tragic and been an enabler for authorities to cover up dreadful errors and failings. My mind goes to the Hillsborough disaster[1] when I think of tragedies made worse by the manipulation of information.

What’s all this about – you might say. I’m giving a thought to the post- accident scenarios that become more common. When major fatal transport accidents happen to planes, boats and trains there’s an instant demand for detailed information.

This is happening in relation to the recent Brazilian ATR aircraft accident and, this morning, to the sinking of a large modern yacht off the coast of Sicily. Both tragedies seem astonishing in their own way. So much of our technological world works so perfectly, a great deal of the time, that we get accustomed to reliability, safety and security. Almost taking it for granted.

Basic technical information, like registration numbers, type and age of the vehicle all surface quickly after an event. Even numbers of fatalities are verified within a couple of days. What gets the speculators going is the answers to the question – why?

A list of circumstantial factors can soon emerge. The time, the weather, the location and the organisations involved. All of this creates a mix that feeds both intelligent and unintelligent speculation. I’m not saying this is de-facto bad. It’s reality.

What’s all this about? There are reports across the media of the “last words of Brazil plane crash pilots.” This speculation surrounds the words spoken in the cockpit and seem to come from someone’s knowledge of a transcript. How can that be? Through international agreement the independent aviation investigation organisations across the globe are committed to a protection of this type of recorded information (Cockpit Voice Reporter (CVR)[2]). Accident flight recorders are there for the purposes of the investigation of an accident or incident.

Back to our modern dilemma. Is it good or bad that sensitive protected information leaks into the public domain before it’s been thoroughly analysed and properly understood? There is a cost to a dilution of the protection of information. For one, it may discourage the voluntary application of safety enhancements, like fitting a recorder to a plane, boat or train.


[1] https://www.bbc.co.uk/news/topics/c8m8v3p0yygt

[2] https://skybrary.aero/articles/cockpit-voice-recorder-cvr

Tragic VoePass ATR72 Crash

2024 was going so well. Looking at the indicator of worldwide fatalities in commercial aviation for the first six-months of this year, and it is exceptionally low. The time between major fatal accidents across the globe is another indicator that my team once looked at on a regular basis. Aviation is an extremely safe mode of transport but when accidents happen, they can be devastating.

Yesterday, the situation changed in Brazil. A VoePass ATR72-500 aircraft[1], registration PS-VPB, flight number PTB2283 crashed in the Brazilian state of São Paulo. The twin-engine aircraft crashed in a residential location.

Yet unknown events resulted in a loss of control in-flight. On-line videos of the aircraft flying show a dive and then a spiralling decent to the ground. The aircraft was destroyed on impact, and it is reported that all lives were lost.

The publicly available flight data shows a sudden decent from a stable altitude[2]. The aircraft was about and hour and twenty minutes into its flight.

Looking at the video information it might appear that local weather may not have been a factor in the accident. However, there was known to be severe icing conditions at the altitude that the aircraft was flying.

It’s speculation on my part but unrecognised severe icing is one of the conditions that can bring about a catastrophic outcome for such an aircraft. It is sad to have to say that there is a record of a major accident to an ATR-72 that has some of the characteristics of this new accident.

In fact, it is one fatal accident that is etched on my mind given that it happened in late 1994, when I was still fresh in my job with the UK Civil Aviation Authority as an airworthiness surveyor. It’s known as much by its location as by the name of the aircraft, namely Roselawn[3]. The accident was extremely controversial at the time.

Crews are told that they may be operating in severe icing conditions but there is no specific regulatory requirement for on-board advisory or warning system on this generation of turboprop aircraft. An ice detection system can serve as a final warning to alert a crew that ice protection is needed.

Work to update the technical document; In-Flight Ice Detection System (FIDS) Minimum Operational Specification EUROCAE ED-103 is completed. Issued in April 2022, ED-103B – MOPS for In-Flight Icing Detection Systems is available[4].

In the case of the current accident, it is a matter for Brazil’s highly capable independent accident investigators to determine what happened. Anything I have written here is purely speculative.

POST 1: Reports of statements made by Agência Nacional de Aviação Civil (Anac) say that the aircraft was in good condition.

POST 2: Accident flight recorders have been recovered from the accident site. Flight recorders retrieved from crashed Voepass ATR 72-500 | Flight Global


[1] https://asn.flightsafety.org/wikibase/409335

[2] https://www.flightaware.com/live/flight/PSVPB/history/20240809/1450Z/SBCA/SBGR/tracklog

[3] https://www.faa.gov/lessons_learned/transport_airplane/accidents/N401AM

[4] https://eshop.eurocae.net/eurocae-documents-and-reports/ed-103b/

Electric Aviation: The Promise of Clean Flight

Electric aviation is not new. Not new at all. The engineers of the past struggled with two factors. Power and weight. A French electrically powered airship was the first aircraft to make a controlled circuit. On 9 August 1884, it flew a circular course of 8 km at a max speed of 14.5 mph. Its electric motor weighed 100 kilograms and its battery weighed 263 kilograms.

It’s not a problem to be able to distribute or use electrical power on-board an aircraft. The problem come in generating enough of it from a reliable source. Today’s “conventional” civil aircraft generate and use large amounts of electrical power. For example, the Boeing 787 has two starter/generators per engine[1]. Electrical power from the generators goes to four alternating current (AC) electrical distribution buses, where it is either sent for use as is (235 V AC) or converted for use by the aircraft systems that need it.

A revolution is taking place in electric aviation. It offers the opportunity to fly cleanly. That said, the traditional technical challenges remain the same. Power and weight. In 140-years battery technology has advanced considerably. But is that enough?

A difficulty that battery powered flying is stuck with is that at the start and at the end of a flight the batteries weigh, more or less, the same as they did from the day of their manufacture. Today’s “conventional” civil aircraft consume fuel. Thus, they are significantly lighter at the end of a flight than they are at the start. Airframes can be designed to take advantage of this fact.

One of the up sides is that a good electric motor can get to an efficiency of 80% whereas a turbo fan engine comes in at around 35%. That sound great until we look at the amount of energy we can store within a given volume. Jet fuel packs a punch. To get the same punch from an electrical battery it would likely be 15 times the size. That’s not good for a practical design. The low battery energy density coupled with the high weight of batteries means that this strategy for large aircraft needs to be put to one side for now.

A modern aircraft engine like the CFM International LEAP, can develop a max take-off thrust of over 30,000 lbf. Two of those engines can safely accelerate a Boeing 737 or Airbus A320 with ease and cruise with good economy. Thus, electrification of the propulsion of this class of aircraft is a long way off. The nearest possible future for propulsion of a B737 and A320 sized aircraft may be hydrogen based.

This explains why the drawing boards are full of small electric aircraft designs where performance demands are more modest. There’s a hope that the continuous development of battery technology will provide year on year gains. Much more than aviation alone demands that battery technology advances.

Developments in hydrogen-electric aviation are catching the headlines. Much of what has been achieved is experimental. I look forward to the day when hydrogen is not used to fill airship gas bags but becomes the life blood of transport aviation. It’s conceivable that will happen in my lifetime.


[1] http://787updates.newairplane.com/787-Electrical-Systems/787-Electrical-System

Turbulence

Turbulence is the result of atmospheric or environmental effects. Afterall, aircraft are craft that fly in the air. This is a hazard that is inherent in flying. Clear air turbulence (CAT) is common. However, extreme examples experienced in commercial aviation are rare. For one, aircraft operators and their crews do their best to avoid known potential atmospheric or environmental upsets, namely bad weather.

En-route turbulence accounts for a substantial number of cabin crew members injuries, and can occur at any time and at any altitude[1]. As far as I know, the UK Civil Aviation Authority (CAA) does not hold detailed data on turbulence injuries occurring on foreign registered aircraft. Numbers of injuries to passengers and flight crew on UK registered aircraft resulting from turbulence are recorded. However, it is not always known whether those injured in turbulence encounters were wearing seat belts.

Nevertheless, I can confidently say that the more passengers that are wearing seat belts during turbulence encounters the less the number of injuries. Deaths in these circumstances are rare. As might be expected fatalities are more likely to results from a combination of multiple causes and factors.

This subject is not immune from airline economics and competition. International flight routes can often be highly competitive. Fought over. So, the route taken, and associated fuel costs, can have an impact on the likelihood of a hazardous weather encounter. In fact, choosing to take routes for the benefit of picking-up specific winds is a common practice.

A high percentage of cases of turbulence events come about by flying too close to active storms[2]. Here there is often visual cues, reports, forecasts and feedback from turbulence encountered by other flights. This all helps crews avoid the worst weather encounters.

With very few exceptions, flight turbulence does not result in fatalities, permanent injure, or structurally damage commercial aircraft. However, turbulence is recognised as both an aviation safety and an economic issue, and it has been steadily increasing. Speculation and some research cites climate change as a reason for this increase. Also, there is the international growth in air traffic and development of new long-range routes.

One thing to say is that until recently, with INTERNET connections now in both in the cockpit and cabin, it could be the case that a passenger could access better real-time weather information than a flight crew. Now, SATCOM connections providing up-to-date weather information are more common on modern civil aircraft types.

There is still more that can be done to reduce crew and passenger injuries during turbulence encounters. There will inevitably happen despite any policy to avoid hazardous weather. The greatest threat to life exists to cabin crew. The cabin is their place of work.

There is potential to develop and employ better airborne detection systems to assist crews. That maybe by enhancing existing weather radar systems. It maybe by new means of turbulence detection using LIDAR, and possibly AI/ML. There is research and innovation that could be done to develop algorithms to better predict turbulence hazards.

Avoidance remains the best strategy.


[1] NASDAC Turbulence Study, August 2004

[2] US CAST briefing in 2004.

Mars steps

It’s strange what thoughts circulate in my head. If I was to say what kicked this off it was probably the story of the Preet Chandi[1]. It’s inspiring how some people see a challenge and just get up and throw themselves into overcoming it. Her commitment and determination are impressive. She was recounting the how and why of her striking endeavours on the radio. What’s much less inspiring are a some of the moronic comments that the web throws-up about her achievements. I hope she continues to take on great challenges and sweeps them aside.

Exploring and going that extra mile is built into the fabric of being human. Fine, it’s not for everyone but that’s no surprise given that there are 8 billion of us on this planet. A magazine popped through my letterbox this week speculating on what Earth will be like when that number gets to 10 billion people. Don’t worry it’s not all doom and gloom. It’s just that the world will be a very different place by the time we get to 2050. Wow, if I stay healthy, I might still be around.

A lot of public policy of the moment seems to be resisting this reality. Honestly building barriers and walls will do nothing whatsoever to build a better world. Cultivating political anxiety and fears about the future is the maddest short-termism that can be imagined. But sadly, there’s a lot of it about. It’s fashionable in the mature democracies around the globe.

Humanity has an endless list of “challenges” and opportunities ahead. Now, I don’t what to sound too much like the Musk man but we’ve a great deal to do off the planet. What we’ve achieved so far is chicken feed in respect of what we have the potential to achieve.

The big one, that taxes the imagination of writers and futurologists is what do we do about our sister planet: Mars. It’s impossible to ignore. It’s not that far away when compared with other distances in space. It’s intriguing in that it was once a water world. Like Earth.

Today, it’s a planet inhabited by robots. The only one we know that is so populated. Rovers drive around sending pictures back of a desolate barren landscape that has an eery beauty. So much of what we know about the place has only been discovered in the last decade.

Human exploration is natural and normal. Do we leave it to robots? Afterall they are becoming ever more sophisticated. Or do we plant boots on the ground and go there to explore in the way we have throughout the Earth. Well, except for parts of the deep ocean.

Here’s what crossed my mind. Just as Polar Preet, broke two Guinness World Records on her journey, so the incentive to be the first person on Mars is something that will land in the history books. The name of the person who makes those steps will echo through the centuries ahead. So, the trip to Mars will not need an incentive. The drive to do it, at almost any cost is already hanging in the air. What’s more complicated is the journey back to Earth. Going on an expedition has a clear goal. Getting back from an expedition has a different goal.

Being someone who recognises the benefits in the reliability of redundant systems it occurs to me that a mission to Mars needs two ships and not one. Both traveling together to the planet. One can be simple and utilitarian. That’s the one crewed as the outward-bound ship. The other, the homeward ship needs to be autonomous, secure and even luxurious. That way the hardest part of the journey, coming back, can be made easier and more likely to succeed.


[1] https://www.independent.co.uk/news/uk/home-news/preet-chandi-sikh-south-pole-b1987047.html