Study finds female astronauts more efficient
phys.org
phys.org
I'm highly air efficient for a man, but only moderately more air efficient than the average of the women I've dove with (as in I've only dove with a couple men as air efficient as I am, but 20-30% of the women I've dove with are MORE air efficient than I am, sample somewhere north of 200 total with a roughly 33% female population).
I can't speak to the rest of the paper's conclusions.
Personally, I see this is less as a real research discovery and more like a cautionary tale on the pitfalls of statistics and the need for multivariate regressions with control variables.
How much that muscle mass means for the given mission is a separate, but relevant factor.
A smaller profile will also help in reducing drag. A smaller frame also need less air in their suit (both dry and wetsuit). This is likely however to impact resistance to cold.
That said, they generally have less capability for work at the same mass.
There seems to be a trade off between efficiency and power density, which is what this study is probably getting at.
There are likely interesting differences based on density and base body functions that scale in non-linear ways. I expect however that all those would be minor gains compared to exertion rate, especially when it comes to oxygen consumption. If we use diving again as an example, a person just floating still will be using less than half the oxygen compared to a person swimming against a mild current. Heavy work can easily go past 4x or higher compared to the oxygen consumption of a person in rest, which is a major problem for rebreather divers who are limited by their equipment in term of scrubbing co2 (for every 1x of oxygen consumed, 0.9x of co2 is produced).
female astronauts have lower water requirements for hydration, total energy expenditure, oxygen (O2) consumption, carbon dioxide (CO2) and metabolic heat production during space exploration missions compared to their male counterparts.
You need to take food with you and have a closed-loop air and water supply whatever the crew looks like, as well as engines, communications, engineering equipment, science payloads, etc, etc. How much does it cost to overspec the "metabolic system" by 60% in that context?
Then again, making everything the size of a 1.5m person rather than for 1.9m people would save on a lot of structural material and therefore mass and fuel[1].
But then again again, how much of the size of the ship is dictated by the size of the crew and how much by other non-biological need?
[1]: which is why chibi "aristo" robots take over in Saturn's Children by Charles Stross, as they're small and suitable for efficient space travel. Large robots may need limbs removed in order to afford transport.
Every single gram that has to have delta-v applied will need more fuel, which needs more fuel, commonly known as “The tyranny of the rocket equation.”
Maybe the crew metabolic efficiency drops the required resources to a level that one or more systems can change what tech they use (step change), pushing the weight even further?
Without further information about what the systems evaluations are, what technologies this might allow the employment of, and a thousand other points of data there is no way to actually answer your question.
EDIT: You added the part about vehicle sizing while I was replying, which is one of those thousands of data points. There are so many follow on effects it’s quite mind boggling.
The Expanse books go into “spacer” evolution but I think that we’d have more short and compact people rather than tall and thin since taking less space is important in space in addition to fewer calories.
Also, there’s a funny bit in Seveneves where people in space cut off their legs because they felt they didn’t need them (spoiler: they did need them).
I thought that after astronaut programs got past their original sexism blocking female astronauts that the other concern was that radiation in space was much more harmful to female reproductive systems than male.
So the future of space work is post menopausal women. Or I suppose short men as well.
What would be interesting is to perform the same comparison indexed on body mass, since many of the differences between male and female requirements seem to be predicated on body mass vs stature differences between male and female.
You can kinda estimate this by comparing a 1.5m male and 1.6m female in their data fields (typical 1.5m male is approximately same mass typical 1.6m female in their dataset). It does seem that a 1.5m male still expends more resources during "aerobic countermeasures" (ie exercise).
Still, interesting stuff. 1.6m female is basically the US 50th percentile height for females. In principle, restricting crew to that criteria wouldn't be too logistically onerous (you still get ~25% of the US population to work with).
Women in general have higher body fat percentages at the same weight, hence lower metabolic requirements.
I'd bet that a 1.6m female strength athlete would have a far higher metabolic requirement than e.g. a 1.6m average office worker guy.
People: "Yep, that sounds good".
SpaceX era: "Women are smaller and more efficient, which is a big deal when fuel costs are exponential"
People: "But have you controlled for X? What about Y? Surely it wouldn't be fair to send up only women. There must be something that is uniquely male and so we must send up at least some men, probably mostly men."
https://en.wikipedia.org/wiki/Donner_Party#%22The_Forlorn_Ho...
With males, their testosterone always gets in the way. (read: 'self-interest')
Yep, this is true in many different fields. Many studies have shown that patients get better outcome with female doctors, for instance.
For the same reason let's use midgets.
If a topic allows only affirmative results in one direction, those same results become statistically impossible to evaluate.
Not sure that is true (could be but..) I vaguely remember reading about runners - the details are very fuzzy after that, but I think if you look in this direction you will find what you are looking for.
I think it was sprinters, about how both would be equally as fast at the start due to -physics of some sort- but the difference in oxygen usage makes the female fall off faster. Or maybe it was endurance runner, kinda wish I payed attention more, but it was definitely about runners & oxygen usage.
The solution - to the extent one exists - is pre registration. I see no evidence that this study was pre registered and thus the usual assumption that it has no meaningful protection from publication bias applies.
Here’s one of the very well known reports of potential impact in a well studied area (fda approval): https://www.nejm.org/doi/full/10.1056/nejmsa065779
Glancing at the paper the basics sound about right to me, but since the exact opposite conclusion would be far less tolerable and less likely to be authored and published, one can't help wonder what factors weren't considered for example.
If this happens to align with "culture-war rhetoric" from people I have no control over or relationship with so be it.
What you wrote might feel correct to you, but have you seen scientific research towards it? If you go by what you feel is right, how do you know you're not being manipulated? Seems like a perfect topic to divide people.
The further you move away from the hard sciences the harder it becomes to prove anything. Math, physics, and biology tends to be fairly easy as these things go; in medicine it already become significantly more murky, and with social sciences it's very hard indeed. I'm not saying there isn't a lot of valuable stuff in the social sciences, because there is, but "I will only accept what is scientificality proven" is a seriously limited view of things.
And yet it's an even bigger mistake to discount the idea of knowledge gain through the scientific process. Remember, we're not talking about two separate attempts to gain knowledge - we have one systematic but flawed attempt, whereas the opposite is simply not trying at all.
Just because you cannot exactly determine the mass of "bias in scientific publishing" doesn't mean you can't try to systematically study it, to find objective metrics by which you determine some order on some scale.
Just think about this from the other perspective. Is there any piece of knowledge you have that is fundamentally impossible to study scientifically? Is there an unwritten law of the universe preventing somebody from formulating a system by which emotionless judgement is denied? If not, why would you not want to see scientific evidence, to at least lessen the chances of you being fooled by the interests of others?
please cite sources
That said, I highly doubt this finding in particular (women needing fewer calories/oxygen) is wrong. It's a well established metabolical fact that women need fewer calories, and it would be bizarre if that didn't translate into less oxygen used.
This is pretty declarative and indicates a certainty on your part. Unfortunately, it is presented without the evidence that led to your certainty.
> Could there be opposite-conclusion studies that were quashed?
This sounds like a bias generated, leading question. However, nuance in text can be tricky.
Giving you the benefit of the doubt, what did you see with this study that leads you to ask this?
If a study found men used LESS resources than women it would of course be surprising and receive closer scrutiny. We see over and over in nature that large things tend to use more resources than small things, of course people would be sceptical. A study having an unpopular conclusion doesn’t necessarily mean that study is especially credulous due to the good peer review it must have had, or that a study with a popular conclusion should be hand waved.