The value of manned space flight?

Umbran · Friday at 10:56 PM

briggart said:
I assumed "pumping energy into the oceans" to be a shorthand for "energy produced on Earth is not radiated into space".

Nope, it was literal. Because for anything else, we get into loss to space, which can be substantial.

briggart said:
...in which case energy from non-renewable sources eventually ends up in the environment as heat.

Well, mostly.

briggart said:
There may be a lag between when energy gets produced and when it eventually ends up in as waste heat, but even if the lag is of the order of decades or even hundred years, it doesn't significantly change the picture.

Picayune aside: Some chemicals we produce, and changes we make, effectively store energy for much longer than a hundred years. Some plastics, for example, don't oxidize on the decade-to-century timescale.

Heck, my suburban house is already over a century old.

Umbran · Friday at 11:04 PM

Ryujin said:
But there are ways other than the direct heat that we output, that can cause catastrophic climate change.

Yes, there are. Water vapor, carbon dioxide, methane, nitrous oxide, and flourinated gases are the main culprits we can put out.

While some of them are pound-for-pound worse than CO2, we'd have to work at it to make the others in quantity enough to be a bigger problem than our current CO2 emissions, which are huge.

The point is more that when we think "catastrophic", it is really about how fragile human systems are.

The Firebird · Friday at 11:08 PM

Umbran said:
Yes, there are. Water vapor, carbon dioxide, methane, nitrous oxide, and flourinated gases are the main culprits we can put out.

While some of them are pound-for-pound worse than CO2, we'd have to work at it to make the others in quantity enough to be a bigger problem than our current CO2 emissions, which are huge.

The point is more that when we think "catastrophic", it is really about how fragile human systems are.

Methane in particular is concerning, because its short term effect is substantial and there is a lot locked up in permafrost. Some heating will release it and cause a powerful positive feedback on a short timescale.

The Firebird · Friday at 11:10 PM

Clint_L said:
My main reason for continuing to support crewed spaceflight is that it is really sexy PR for science. Which is itself a great thing - we need all the people excited about science that we can get. At a personal level, I think space flight and space science in gereral are exciting and fascinating, even when there is no immediately obviously application.

I wish humans got as excited about, say climate science and vaccine science, but our brains seem wired for novelty, not for slow, incremental, meticulous study and experiment. But at least a few people who get jazzed by science through the Artemis missions will go on to become scientists, and that's a good thing.

It always seemed to me much more the engineering that got people exciting than the science. Everyone has seen the pictures from Cassini, but not many could tell you about it's science objectives.

The Firebird · Friday at 11:12 PM

Umbran said:
The Paris Agreement was trying to keep change down below 2C, really hoping for under 1.5C, because by about 3C, the impacts on society start becoming severe enough that our history does not give us a handle on the sociopolitical changes that would follow. Humans would be alive, but the existence of modern social order becomes... dicey?

Expect to see stratospheric aerosol injection or other geoengineering efforts before the civilization destroying stuff. Those have their own risks, which in many cases are substantial.

Umbran · Saturday at 4:57 AM

The Firebird said:
Expect to see stratospheric aerosol injection or other geoengineering efforts before the civilization destroying stuff. Those have their own risks, which in many cases are substantial.

Maybe? If you haven't noticed, taking action ahead of time is not our forte.

Pale Violet Light · Saturday at 5:36 AM

The Firebird said:
Expect to see stratospheric aerosol injection or other geoengineering efforts before the civilization destroying stuff. Those have their own risks, which in many cases are substantial.

Why bother? Everyone of consequence will be safe in their off-world habitats or climate-controlled bunkers.

Umbran said:
Maybe? If you haven't noticed, taking action ahead of time is not our forte.

I’d say human history is an excercise in closing gates after bolted horses, but in general we don’t even bother with that part.

Tigris · Saturday at 11:32 AM

The Firebird said:
It always seemed to me much more the engineering that got people exciting than the science. Everyone has seen the pictures from Cassini, but not many could tell you about it's science objectives.

Definitly!

I just yesterday spoke with an acquaintance of mine. He is a school droppout and not really good at math etc. But he did watch the artemis start live and is really excited about it.

Rockets and other such physical things are easy to grasp.

But the fun thing was that he was annoyed about how extremly unefficient these old rockets are they use for these missions. As in because of bureaucracy they could not change research towards reusable rockets which would have been much less expensive per start.

Umbran · Saturday at 4:49 PM

Tigris said:
But the fun thing was that he was annoyed about how extremly unefficient these old rockets are they use for these missions. As in because of bureaucracy they could not change research towards reusable rockets which would have been much less expensive per start.

That's not entirely accurate. It is not "because of bureaucracy".

We note that SpaceX has become known for "rapid unscheduled disassembly" of their equipment. No loss of life, but during development, they have a tendency of blowing up, crashing while trying to land, and so forth.

As a development strategy, there's nothing wrong with that - the tests are instrumented up one side and down the other, so they learn a ton from every failure, and use that to improve the next iteration.

NASA, as a matter of public image, is EXTREMELY risk-averse. While they accept there is risk in every launch, they always work to minimize risk, even in development. Repeated headlines of "NASA rocket blows up" are anathema to them. That means internal development of significantly new launch hardware takes them a long time, and a lot of money. So, for Artemis, they're re-using technology that they already know works.

Stalker0 · Sunday at 7:07 PM

Clint_L said:
I think space colonies are a completely implausible pipe dream. The incredible expense to make them work, let alone be self-sustaining, dwarfs what it would take to settle the most inhospital place on our planet. In fact, I don't think a self-sustaining colony is possible, barring finding and somehow reaching a largely hospitable world. I do think a temporary colony for the purpose of, say mining an asteroid, could justify the incredible expense, though I think by the time we get to that stage, if ever, robots will be the only realistic choice.

I do think we have to make several big leaps in technology to make a viable colony a reality.

I'll note just one.....we do food incorrectly.

We stuff biomatter into soil, add photons, water, and nitrogen....wait for the biomatter to grow (consuming a lot of energy), and then we pull it from the its water + nitrogen bath and eat it. We have been doing that for 5000 years. Sure we have gotten way better at it, but its still at its core a 5000 year old technology.

If your going to space with hostile soil and hostile conditions, you have to do far better. What we need to learn to do is generate glucose from water, electricity, and carbon dioxide. Basically become our own plants. Do it at scale. Food production should be a factory process....farming should go the way of the dinosaur. We have started this idea with Protein right now, aka the "impossible burgers", but there are still several steps to go to get it to the final destination.

That's the kind of tranformative technologies that make space colonization go from "yeah right" to "tell me more".

Its also highly likely we will have to invest in Geoengineering technologies, as we do not have the human will to stop climate change the "correct way". Very sad, but assuming we don't kill out planet with it, we will learn a lot about what terraforming might look like in the process.