Why is it assumed that space flights have to be safe?

Question

On the one hand, space travel is a completely novel technology and less than 1000 people have traveled outside the planet. On the other hand, every accident in space involving humans is treated as a big deal (such as the Challenger disaster) and there's an implicit assumption that space travel must be safe.

But wouldn't it be better for space exploration if we inherently assumed space travel is incredibly risky and that astronaut deaths are to be expected? I.e. if the Challenger disaster was treated as a cost of doing business, the Space Shuttle program might've still been operational. Obviously astronauts would have to be informed about the potential risks, but I'm sure there would still be tens of millions of people willing to apply for the job.

Answer 1

But wouldn't it be better for space exploration if we inherently assumed space travel is incredibly risky and that astronaut deaths are to be expected?

NASA and Roscosmos do assume space travel is inherently risky and that astronaut / cosmonaut deaths are to be expected. NASA asks their astronaut candidates (with a psychiatrist present to evaluate the responses) if the ASCANs accept that spaceflight is inherently risky and that they may die if accepted into the astronaut corp.

The goal is to make it so that 99.73% of one-way space flights end up with no one dying or suffering serious injury. The typical consequence of a serious mishap is death for all on the vehicle. That is an incredibly low bar.

Imagine that 99.73% safety margin was the safety margin for one-way car trips. Many people in the US make well over 1000 one-way car trips per year. They drive to and from work, to and from a store, to and from a gas station, and so on. If 99.73% of those trips was "safe", the odds of surviving a year involving 1000 such one-way trips is less than 7%. People would think twice (multiple times) before hopping in a car.

Imagine that 99.73% safety margin was the safety margin for commercial plane flights. There are 115000 commercial plane flights per day. If 99.73% of those flights didn't involve death for all involved, that would mean over 300 flights per day that did involve death or serious injury. Hardly anyone would fly under such circumstances. It took two fatal crashes separated by several months of Boeing's 737-MAX for the 737-MAX fleet to be grounded worldwide for well over a year.

One final reason that that 99.73% safety margin is an incredibly low bar is that that is the design goal. Vehicle designers et al. work very hard to achieve that goal. Testers, simulation designers et al. work very hard to test whether that goal is met. However, just as six-sigma manufacturing strives hard to get the design defect rate to about four per billion, the reality is that the actual defect rate, even with six-sigma manufacturing in place, is about 3.4 defects per million.

Vehicle designers, software designers, testers, et al. inevitably miss some of the things that can go seriously wrong with a crewed spacecraft. The design goal of less than 3 serious mishaps per 1000 flights is most likely closer to a serious mishap every few hundred flights or so in reality.

Answer 2

I think you're mixing up public perception vs engineering reality. For example, you mention the space shuttle...

if the Challenger disaster was treated as a cost of doing business, the Space Shuttle program might've still been operational

You have some facts mixed up.

The space shuttle program continued after the Challenger disaster in 1986, and even after the Columbia disaster in 2003. The flights resumed despite continuing to have the same problems that lead to Columbia breaking up: shedding debris striking the heat shield during launch. Instead they mitigated the risk with inspections and the ability to repair the heat shield in space.

Even so, we would not be flying the Space Shuttle today.

The real reason why the space shuttle program was shut down was that it was old, risky, and waaay too expensive. It was designed to be reusable so it could build Space Station Freedom in the 90s and then shuttle back and forth between the Earth and the station at the pace of dozens of launches a year. But Freedom didn't happen (it eventually became the ISS). With no station for the space shuttle to shuttle to, flights were infrequent and the whole concept wasn't economically viable.

In 2004 it was decided the Shuttle was needed to ensure the ISS was built. Meanwhile a newer and cost effective crewed vehicle would be built in 2008, the Crew Exploration Vehicle aka Orion. With a new vehicle flying, the shuttle would retire in 2010. Orion never happened, but they retired the Space Shuttle anyway. It was too old, too unsafe, and too expensive.

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So space is risky. But you want to mitigate that risk for several reasons. Here's the most important one: If the rocket blows up, the mission fails. The mission was the whole point.

Here's some other reasons:

1. Space hardware is very expensive, particularly the payloads. Nobody wants their billion dollar space telescope blowing up on the pad.
2. Space launches are very public. I watched the Challenger disaster live on TV in school.
3. Space launches are a point of national pride. They represent the pinnacle of nation's technological achievement and it's politically embarrassing to have it blow up.
4. We value human life.
5. Astronauts are considered heroes.

It's one thing to blow up empty uncrewed rockets while you're developing new technology, but it's an entirely other thing to put highly trained heroes, and the mission and the very expensive hardware and all the effort, at unnecessary risk.

It is expected that they will do everything we can to mitigate the risks both to the people and to the mission.

Answer 3

My heavens… my sweet heavens. I’m going to try hard to maintain my composure and professionalism, but it’s hard as a space professional to deal with debasing of our work.

The very notion that shooting up one more person means one more person shot up… and therefore “more done git”… is a child’s notion of space exploration. Much like the schoolchildrens’ experiment of putting up an ant colony into orbit aboard the shuttle, when given a chance in the late ‘80s to fly their own experiment. Because ants in space! In space! They’re in space! (I wonder if this is how Christian ecclesiastics feel about Santa Claus as theology.)

The notion of humans in space because humans in space is a late-‘50s notion, already dated by the late ‘60s, let alone the mid ‘70s. Human presence aboard space vehicles needs a mission requirement and a success criterion, which in the first few years was simply proving (in the sense of field trials, i.e., proving grounds) that it could be done, then proving further details and decimal places on the criteria. After reasonably concluding that it could be done, humans in space because humans is then a stunt, not a fulfilled requirement. This was the path of the aviation industry, after the experimental era (1900s to ~World War I) led to the Barnstorming Era (Air circuses and sideshows), because neither air mail nor airlines turned a profit without massive subsidization.

We are not staging circuses for public amusement… or at least, I refuse to. Private billionaires are tacitly doing so, and as long as it’s their money then they can blow it. And yet, neither Branson, Bezos, Ansari, or Musk are interested in throwing their billions to hacks and amateurs. In the direct sense, a billion can disappear before you realize it, and then you’re down a billion. In the operations sense, these vehicles (and more) operate in ranges, airspaces and orbital zones that result in consequences for failure. Rutan had a propellant explosion ON THE GROUND that killed a few of his employees- even aside from labor violations, you won’t keep your operation running when your own staff fear for their jobs/lives/whatevers. Dropping a live rocket on a populated area can also make a billion disappear before you know it, so these (current) billionaires are thinking twice before approving plans and cutting metal.

And those are the stunters, at least at first glance. Branson and Bezos actually hope to (eventually) make their money back and then some by selling tickets; Musk plans on making the investment pay back via Starlink, third-party payloads, DoD/NASA contracts, etc. (There’s the Mars PR, but it’s possible that the notion of “Mars!” is a marketing/advertising gambit for the benefit of the greater operation.) The rest of us are NOT doing some stunt: space because “space!”.

Therefore, making the success criteria lower, not higher, is less than possible, it’s actually harmful to our industry (at least, by certain metrics). The loss of schedule due to post-investigation grounding leads to loss of funds (time is money), loss of staff (trained engineers can jump to other fields), loss of capital via investor flight… and in the general sense another loss of confidence may lead to yet another “space winter” just like for AI.

Santa Claus can lower his sleigh margins because… Santa and the sleigh aren’t real, and the presents will arrive without consequences. You can also search for the schoolchildrens’ space ant project to see what waste looks like (though no real monetary consequence occurred). Meanwhile, those of us with real paychecks for successfully meeting our real mission criteria- not amusing a fickle and distractable audience- won’t waste our time and effort.

My source: over twenty years of academic/DoD/NASA work. With paychecks to match, because the goal wasn’t amusement. (Therefore, almost all of those projects were uncrewed, not wasteful.)

Answer 4

Why is it assumed that space flights have to be safe?

It is because of a concept called Duty of Care.

Which basically boils down to, not willingly or knowingly harming others. To do one's best to ensure other people are not adversely affected by whatever one does or does not do.

People have a right to expect they can go about their lives, including work, and not be injured or killed and employers have a duty of care to ensure their employees and contractors are not injured or killed while in their employ.

Space flights, like any other activity, would cease if the failure rate was 100 percent or close to it.

Anything that anyone does has a risk of injury or death associated with it. The risk can never be eliminated, but it can be reduced and that is one of the functions of Duty of Care.

During the development of the Apollo space program, astronauts were concerned about the lack of safety with the Block 1 version of the command module, but in the rush to get ahead in the space race very little, if anything was done until the Apollo 1 disaster which claimed the lives of three astronauts.

That prompted a redesign and a cessation of testing using astronauts for 18 months. The Block 2 version "eliminated the dangers of wiring", that initiated the fire in Apollo 1.

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The Apollo 13 incident resulted in a spare oxygen supply being installed on the opposite side of the service module.

I forget which book I read it in, but Frank Borman's wife was very unhappy with senior management at NASA when she learned her husband was going to fly on an untested mission to the Moon. She didn't like the idea of her husband taking the risk of going to the Moon in Apollo 8.

Answer 5

Ask the Rooskis about that. It's not just that unsafe space travel is Bad For Business (turns taxpayers away from future investment), it's that, like any transport mode, space travel has to eventually be fit for everyone. Yes, a certain amount of risk is acceptable and also to be expected. However, the mitigation of that risk has to be a top priority to show that the travel modality can be viable long term.

600 years ago travel from the centers of "civilization" to The New World was considered dangerous not because the ship might sink of its own accord before landfall, but because of the inherent dangers of any long sea journey. How many adventurers do you think would be willing to risk dying in the open sea just because the vessel was a piece of junk?

Let's focus on getting to the places we want to visit and also getting back safely. There's no reason safety can't be a top priority in doing so. Modern technology allows us to sidestep risks that had to be accepted with gritted teeth in past generations. Keep yer eyes on the prize, dooode.

Answer 6

Frame Challenge - the Question is Unclear

The proposal is to reduce safety for some reason. The gain in that tradeoff is never stated. Is it it to reduce schedules, reduce cost or what?

Also, what's the long-term benefit of the tradeoff? What's the end-goal here? Again, that's never stated. Answers make assumptions about those two items but the asker never comes right out and says.

Answer 7

Astronauts understand that space travel is risky, they are willing to accept the risk if the mission is worth it. The astronauts who flew on the Hubble repair missions thought that their work to enable the great science that Hubble collects is worth the risk of life, but a proposed mission to recover Hubble so it could be placed in the Smithsonian was not considered worth the risk.

NASA doesn't want suicidal astronauts. The psychological exam is full of subtle ways to fail out of the program. When the NASA psychologist asks you if you want to come home from your mission, the only correct answer is yes, any other answer will get you bounced out of the program.

Space flight is not the same as commercial air travel. Air travel is generally safe because airlines make thousands of flights per day and the experience builds up. The technology is not comparable, it takes 900 times as much kinetic energy to put something or someone into orbit as it takes to fly them in a passenger aircraft. Any vehicle that can propel itself into orbit is going to be inherently dangerous. We take our children on airplanes to go visit Disney World, would you put your children on a space shuttle?

It might be fair to compare space flight to military service. People who volunteer for military service know that there is a possibility that they could die in combat, but they are willing to accept that risk to serve their country. The early space program was the moral equivalent of war by other means. Frank Borman said that he did not go to the moon as an explorer, he went as a soldier in the cold war.

Astronauts are not the national heroes that they were in the early days. How many Americans can name the current crew members of the ISS? How many can name one of the other six Challenger crew members aside from Christa McAuliffe?

In some respects manned spaceflight is a relic of the early science fiction stories, in which a human crew had to explore space because early SF writers failed to imagine that robotic spacecraft could collect data and radio it to Earth without a need to come back. With few exceptions, such as repairing Hubble or collecting rocks on the moon, most scientific missions can be done just as well by robots.

Humans also are very irrational about risk assessment, worrying a lot about very rare possibilities and accepting much more common risks such as smoking and poor diet. We lose 30,000 Americans in highway accidents each year but we are willing get into our cars every day because we rationalize that it won't happen to us.

Answer 8

Why do you think deaths are the issue here?

The issue for all of these isn't the deaths of people. It's failure of the mission.

Challenger wasn't just going up there to take some pretty pictures. The primary mission was launching one of NASA's TDRS satellites, which (after all the birds were launched) let NASA remain in permanent contact with everything in orbit, all the time. NASA may publicly claim that this was intended to allow continuous communication with civilian space missions - but it's not exactly a secret that this was also used to allow permanent contact with US spy satellites. In other words, losing that satellite meant a delay in getting this network established to use spy satellites to their full potential, and a more serious vulnerability if anything went wrong with the first (and at the time, the only) relay satellite in orbit.

Columbia wasn't just up there for fun either. It was a science flight, running experiments which needed to be in zero-G, and testing orbital observation kit. Through good luck, a lot of the experimental data was salvaged, but only through luck. Without that luck, all those experiments would have been lost and people would have had to do it again. It's not cheap to put stuff into orbit, so this isn't just done on a whim. Some university or government department has to find another few million bucks to do it all again, and that's not trivial.

Ariane proved that if you want to get anything into orbit, it's way more reliable and way cheaper to use remote/automated systems. The infrastructure to keep humans alive is heavy and fragile. There simply isn't a mission benefit to people being up there. Even exploration doesn't need people.

Where do we need people? Precious few places, actually, and that's why the ISS is such a white elephant.

The only place which genuinely needs humans involved is if you plan to stay wherever you're going. The aim of going to the Moon was not simply to go there, it was to establish a missile base there which the Russians could not easily target. By 1969 it was pretty clear there was no military justification for that, and the vast cost of setting up and maintaining a base (especially given technology levels of the time) was unjustifiable. One of the few benefits of the ISS has been to study long-term spaceflight, which is a key enabler for any future colonising mission to Mars.