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Comment Re:The definition is fine (Score 1) 97

Exactly. I think Stern's always been on the right side of this. The original paper that the Stern-Levison parameter comes from has a great system laid out, where you have a bunch of adjectives that you can apply to different bodies based on their varying physical (composition, size) and orbital parameters, and you can use any combination of them as needed. Which seems to me to be so obviously the right solution.

Comment Re:The definition is fine (Score 2) 97

Saying pluto is a dwarf planet seems pretty good to me as it gives it a special place among planet like objects already.

If they had simply stopped there, that wouldn't have been a problem. The problem is that they didn't. They declared that dwarf planets aren't planets at all - which is nonsense. Mars has far more in common with Pluto than, say, Jupiter. If anything should have been separated out, it's the gas and ice giants from the rocky/icy planets.

Hydrostatic equilibrium is a very meaningful dividing line to split groupings on. If a body is in hydrostatic equilibrium, it's experienced dramatic geologic change in its history - differentiation, tectonics, internal heating, generally fluids (particularly liquid water), and on and on. It's the sort of place you go if you want to learn about planetary evolution or search for life. If a body is not in hydrostatic equilibrium, it's made of primordial materials, preserved largely intact. It's the sort of place you go to learn about the formation of our solar system and its building blocks.

It's rare that nature gives you such clear dividing lines, but when it comes to planets, it has. It's not perfect - you can (and do) have bodies that straddle the border and are only partially or slightly differentiated. But in general, nature has drawn an obvious line in the sand, and we should respect that.

if the object is really big and clear

Is Earth's orbit clear? No, we have a huge massive object co-orbiting with us. Is Neptune's orbit clear? No, it has Pluto in it. They try their hardest to pretend that the IAU actually chose a "gravitationally dominant" standard, but that's not what they actually put in the definition. The standard in the definition is "cleared the neighborhood".

And it's based on a false premise - that each planet cleared its own neighborhood. Which is just pseudoscience. All of our models show that Jupiter, and to a lesser extent Saturn, cleared most of the solar system, including the vast majority of the clearing around Mars, and a good fraction around Earth (lesser around Venus). Mars did not clear its own neighborhood. Nor is it gravitationally dominant in its neighborhood; the vast majority of asteroids are in orbital resonance with Jupiter and not Mars.

And I've heard some people try to sneak around this by saying "Okay, maybe it isn't gravitationally dominant / cleared its neighbood now, but it has enough of a Stern-Levison parameter that it would have been had Jupiter not existed". First off, that's changing the definition yet again (to "would have cleared its neighborhood if no other planets were there"). But beyond that, it's abuse of the Stern-Levison parameter. The Stern-Levison parameter is built around a body's ability to clear asteroids - bodies with the current size and orbital distribution of our asteroid belt. Not protoplanets. In the early solar system it was the ability to clear protoplanets that caused neighborhoods to be cleared. Jupiter got rid of some really massive things that were forming in and near the inner solar system. There's a reason why our planetary system has such an unusual size distribution: the inner planets start getting bigger, the stop getting bigger, then get small, then debris, then something huge. That "something huge" stripped the building blocks out of the inner solar system, preventing it from becoming dominated by super-Earths. Saturn appears to have been our savior - its (delayed) formation appears to have stopped Jupiter's inward migration.

And even just going with the Stern-Levison parameter - Neptune has a Pluto-sized body in its "neighborhood". Now, Pluto may be small compared to Neptune, but compared to Mars it wouldn't be - yet Mars has a much lower Stern-Levison parameter than Neptune. Again: the only reason Mars doesn't experience stuff like this is because Jupiter cleared its neighborhood for it.

Comment Re:Maybe (Score 1) 97

Clearly given that people like Stern have regularly given interviews decrying the decision, and going so far as to call it "bullshit" (can you say that at NASA?), it's clearly not the storm in a teacup that you want to present it as.

What the proponents did was take a term widely used by planetary geologists and have it mean something completely different - akin to dentists suddenly declaring to doctors that the heart is no longer an organ and to stop referring to it as one. And contrary to your presentation of why they did it ("to make it easier to write journal articles") without fail every last supporter I've seen interviewed about their vote has given some variant of the following reason for why they voted the way they did: "I don't want my daughter having to memorize the names of hundreds of planets." Which is so blatantly unscientific it's embarrassing that such a thing would influence their decision at all on a scientific matter.

The IAU vote was narrow, at a conference only attended at all by a fraction of its membership, on the last day when a lot of the people opposed to the definition they passed had already left because it had looked up to that point like there was either not going to be a vote at all , or one on a hydrostatic equilibrium definition - all options that they were fine with. Only 10% of the people who attended were still around.

I have a lot of issues with the last vote, and that's just the start. Here's my full list:

1. Nomenclature: An "adjective-noun" should always be a subset of "noun". A "dwarf planet" should be no less seen as a type of planet than a "dwarf star" is seen as a type of star by the IAU.

2. Erroneous foundation: Current research agrees that most planets did not clear their own neighborhoods, and even that their neighborhoods may not always have been where they are. Jupiter, and Saturn to a lesser extent, have cleared most neighborhoods. Mars has 1/300th the Stern-Levison parameter as Neptune, and Neptune has multiple bodies a couple percent of Mars's mass (possibly even larger, we've only detected an estimated 1% of large KBOs) in its "neighborhood". Mars's neighborhood would in no way would be clear if Jupiter did not exist - even Earth's might not be. Should we demote the terrestrial planets as well?

Note that the Stern-Levison parameter does not go against this, as it's built around the ability of a planet to scatter a mass distribution similar to our current asteroid belt, not large protoplanets.

3. Comparative inconsistency: Earth is far more like Ceres and Pluto than it is like Jupiter, yet these very dissimilar groups - gas giants and terrestrial planets - are lumped together as "planets" while dwarfs are excluded.

4. Poor choice of dividing line: While defining objects inherently requires drawing lines between groups, the chosen line has been poorly selected. Achieving a rough hydrostatic equilibrium is a very meaningful dividing line - it means differentiation, mineralization processes, alteration of primordial materials, and so forth. It's also often associated with internal heat and, increasingly as we're realizing, a common association with subsurface fluids. In short, a body in a category of "not having achieved hydrostatic equilibrium" describes a body which one would study to learn about the origins of our solar system, while a body in a category of "having achieved hydrostatic equilibrium" describes a body one would study, for example, to learn more about tectonics, geochemistry, (potentially) biology, etc. By contrast, a dividing line of "clearing its neighborhood" - which doesn't even meet standard #2 - says little about the body itself.

5. Mutability: Under the IA definition, what an object is declared as can be altered without any of the properties of the object changing simply by its "neighborhood" changing in any of countless ways.

6. Situational inconsistency: (Related) An exact copy of Earth (what the vast majority of people would consider the prototype for what a planet should be), identical down to all of the life on its surface, would not be considered a planet if orbiting in the habitable zone of a significantly larger star (harder to clear zone), or a young star (insufficient time to clear), a star without a Jupiter equivalent (no assistance in clearing), or so forth.

7. Ambiguous definition: There is still no consensus on what defines having "cleared the neighborhood" - in particular, what the "neighborhood" is.

8. Lack of terminology: Exoplanets - indeed, including any potential Earthlike planets - are arbitrarily declared to not be planets. Meaning that exoplanets are not actually planets according to the IAU. Ironically, the IAU has an exoplanets working group called "Executive Committee Working Group Public Naming of Planets and Planetary Satellites"... tasked with naming things that it doesn't consider planets.

9. Inability to describe exoplanets even if not ruled out: There is no way that even if exoplanets hadn't been arbitrarily ruled out that one could ascertain whether a body has met a "cleared the neighborhood" via observations from Earth. A definition based on hydrostatic equilibrium would be far easier to ascertain.

10. Failure to address binary objects. Self-explanatory.

11. Unscientific motivation: The primary reason cited by everyone interviewed thusfar for choosing an exclusive standard over an inclusive standard is along the lines of, "It would be too hard for schoolchildren to memorize the names of all of them". This is such a blatantly unscientific standard that it doesn't even bear going into, and leads to absurd consequences when applied to other fields, such as the AMA declaring that there's only 8 bones in the human body and all others are "dwarf bones" that aren't real bones, or the USGS declaring that there's only 8 rivers in the world and all others are "dwarf rivers" that aren't real rivers, all for the purpose of making things easier for students to memorize.

12. Resistance to accept the diversity of reality: In every scientific field, the universe continually presents those making discoveries with a wide range of diversity. This is almost universally accepted in an inclusive manner, subdividing groups into subgroups, and subdividing those further. We will continue to find new types of planetary bodies in a wide range of diversity - large terrestrial planets, dwarf-scale planets, gas giants, ice giants, hot jupiters, super-earths, water worlds, supercomets, extremely large bodies orbiting as moons, planets without parent stars, and so forth. Rather than trying to hide diversity, science is supposed to embrace it.

13. Discouragement of exploration among the public: The term "planet" has a deep and meaningful place in the public mind, as a body worthy of exploration, perhaps even eventually colonization. "Small solar system body" does not. Public support for scientific exploration to these diverse and fascinating worlds should not be discouraged by poorly chosen names. Quite to the contrary, it would be worthwhile if fascinating worlds the diameter of Mercury, like Ganymede and Titan, were given the same level of attention with a label such as "planetary moons" (note again: an "adjective-noun" is a subcategory of "noun").

14. Distrust of the scientific population among the public: Images of discontent scientists sniping at each other and divisive voting on controversial "truths" have a profoundly negative consequence on the public's view of the scientific community. Anyone who spends any time looking at any of the internet commentary on the dwarf planet decision will find them full of comments along the lines of "Scientists can't even agree about whether Pluto is a planet, why should we trust them about global warming?" I wish this were hyperbole, but I've seen it far too often to ignore it.

15. Poor voting statistical representation: While 4% of the IAU would make up a statistically significant sample if chosen at random, the people involved were not "chosen at random". The people present were "those who could take a trip to Prague and didn't have to leave before the closing ceremony", which leads to numerous potential biases. As Owen Gingerich noted, "There were 2,700 astronomers in Prague during that 10-day period. But only 10% of them voted this afternoon. Those who disagreed and were determined to block the other resolution showed up in larger numbers than those who felt 'oh well, this is just one of those things the IAU is working on'." In this day in age where electronic balloting is simple to implement, that the IAU would be willing to make charged decisions on a 60% vote of a non-random 4% of the membership is highly inappropriate.

16. Wrong people making the decision: Only a small percentage of the IAU are planetary scientists, who are the actual people who should be the ones making decisions about what makes up a planet. Letting people who study stars decide what counts as a planet is akin to letting dermatologists decide how to treat a heart condition - hey, a doctor's a doctor, right? Just like when meteorologists or chemists make claims that global warming isn't real - a scientist is a scientist, right?

17. Making the decision before gathering the data: For most of the history of humankind's knowledge of Ceres and Pluto, we have not had any missions underway to explore them. They were just poorly resolved points of light. But at the time of the IAU vote, at long last, we had launched New Horizons to Pluto and were preparing Dawn for launch to Ceres. Yet it was at this narrow interval, between actually launching craft to gather data about the bodies, but not having them arrive, that the IAU decided to make their declaration. Making scientific declarations about objects that you know little about when vast amounts of data are coming in the pipeline - data that could influence members making the decision - is profoundly unscientific.

18. Not following through on its own declarations: The IAU decision declared that it would continue to name new dwarf planets as new data comes in. Yet there's not been a new declaration since 2006. We have far better data than we had to make declarations of dwarf planets in 2006, and there's a long list of them awaiting declaration - where's the IAU? For example, Quaoar's diameter is known to a mere ±5 km and is significantly larger than Ceres. Even the lower bound of 2007 OR10 is larger than Quaoar. Why aren't they and countless others on the list? It increasingly looks like the IAU just wanted to make its declaration purely for demotion purposes rather than for its stated purpose of categorization.

19. Disagreement with the IAU is so intense that those who disagree are simply ignoring it - a process that began in the literature almost immediately (example:, let alone in conversations with the public (example: any press conference with the New Horizons team). This not only renders the definition meaningless but serves to undercut the IAU's authority in other issues (such as naming).

20. Beyond the major points I could go into a bunch of nitpicks about the poor wording the IAU put forth in general. Such as how Jupiter doesn't actually meet their definition because the sun and Jupiter orbit a point (the sun-Jupiter barycentre) that spends most of its time outside the sun. It's often mentioned how Neptune doesn't meet their definition because of their use of the term "cleared the neighborhood" (implying removing all other large objects) rather than being gravitationally dominant / forcing other bodies into resonance. But because of that, even the Earth doesn't meet that definition because Earth's moon - which orbits the sun as much as the Earth does, despite also orbiting the Earth - is not cleared. Indeed, the IAU definition accepts that a body can both "orbit the sun" and be "a satellite" (see rule #2), yet they don't mention the satellite exclusion in rule #1, thus making Earth fail section (c) of #1. Using a "gravitationally dominant" definition rather than a "cleared the neighborhood" definition would have fixed this problem, but they didn't. Even if one chooses to ignore this, Earth's moon (despite being larger than most dwarf planets) gets classed not as a dwarf planet or even as a moon, but a "small solar system body", because - as they observe in #2 that objects can be both satellites and orbit the sun as well - it fails the conditions in #1 and #2 but meets the orbital condition in #3, thus is a "small solar system body". If you choose not to ignore that they choose the wording "cleared the neighborhood" rather than "gravitationally dominant" in #1, then Earth too is a "small solar system body". These are, of course, nitpicks, and are more ambiguous than the previous points; they're presented simply to show how hastily the current definition was come up with and how poorly thought out it is.

Submission + - Scientists Seek To Reinstate Pluto As A Planet - And Many More

Rei writes: After several years of publicly complaining about the "bullshit" decision at the IAU redefining what comprises a planet, New Horizons programme head Alan Stern and fellow planetary geologists have put forth a new definition which they seek to make official, basing planethood on hydrostatic equilibrium. Under this definition, in addition to Ceres, Pluto and other Kuiper Belt objects, large moons like Titan and Europa, as well as our own moon, would also become planets; "planet" would be a physical term, while "moon" would be an orbital term, and hence one can have a planetary moon, as well as planets that orbit other stars or no star at all (both prohibited under the current definition).

The paper points out that planetary geologists already refer to such bodies as planets, citing examples such as a paper about Titan: “A planet-wide detached haze layer occurs between 300-350 km above the surface; the visible limb of the planet, where the vertical haze optical depth is 0.1, is about 220 km above the surface”

Comment Re: Great idea... But there is a problem... (Score 1) 302

They didn't die after a few minutes - they lasted for 1-2 hours. And they didn't cost a billion dollars, they were built on the cheap. The Soviets launched almost all of their Venus missions in pairs because they considered it likely that something would blow up or fail at some point along the way - not a rare situation, a number of their Venus missions never even left Earth orbit, and some didn't even get that far ;). But of missions that actually got to Venus, they had great success, and even had one mission "rescued" by Venus (they designed it to parachute down, but the parachute broke - but the atmosphere slowed the fall so much that it survived the impact anyway).

For exploring Venus, if you're wanting PR, the Vega approach is the right one - aerobots, optionally paired with sondes. Aerial vehicles can fly for long periods of time studying the planet, and there's a number of exciting missions related to this being worked on (just waiting for funding). As for surface lifespans, they don't have to be limited. There's work on probes designed to "run hot" so that they don't need any (or only minimal) cooling, and there's also work on probes designed to lift off (bellows balloon) to a cooler layer of the atmosphere (to have any length of time to examine / process samples, cool down, etc) before re-descending any number of times. If you're only talking something with a ~2 hour lifespan on the surface and nothing else, you're talking something cheap, Discovery or at most New Frontiers class - not Flagship.

The main thing that's held everything back is that NASA almost never funds anything related to Venus. The last dedicated NASA mission to Venus (not counting flybies to other destinations that used Venus as a gravitational assist) was the Magellan probe, nearly three decades ago. And that came a decade after the previous NASA mission to Venus. Easiest planet to get to, and they almost never fund missions to study it. It's embarrassing.

Comment Re:Echo-chamber fake news (Score 2) 403

There were a lot of contributing factors, but yes, this sadly was one. The Thiokol engineers were against launch, but they failed to make a sufficient case as to why exactly they felt the O-rings were unsafe (there actually was a Thiokol document showing that not only was O-ring failure high at low temperatures but that the second O-ring ceased to be redundant - but they didn't have the document available to them). The Shuttle program managers were getting mad at them for insisting on delays due to the low temperatures without being able to back it up (one of them said something along the lines of "My god, Thiokol - when do you want me to launch, April?") and eventually the Thiokol management dropped their objections (even though the engineers were still strongly against launch). The engineers all gathered round to watch the launch on TV, thinking it was going to explode on the pad. When it lifted off they all breathed a sigh of relief, only to have it dashed during the explosion.

Comment Re:Echo-chamber fake news (Score 5, Informative) 403

Really, I have to give them credit where credit is due: by repeatedly pointing out errors (however trivial) out of the tens of thousands of news stories that are published every day, they've managed to get their supporters to the point where they'll trust a new story on more than they will an actual newspaper. It's a real masterstroke in terms of controlling the narrative. "Anything negative you hear about me, it's fake, because there exist cases where newspapers have made errors, and we've selectively presented you only with those cases to create a narrative for you that newspapers are packed full of fakery." Not just newspapers - fact checkers, peer-reviewed articles, even official government statistics - all fake, because they've been presented with every case people can get their hands of of error, without the balancing context of the 10000x more that wasn't in error.

In the words of XKCD: "Dear God, I would like to file a bug report". ;)

It's the same thing that contributed to the Challenger explosion. They had a nice clean graph in front of them that plotted O-ring failures vs. temperature. There was no clear trend visible on the graph. The problem was that they omitted the successes, the cases where there were no O-ring failures. Here's what it looked like with that added in. All of the sudden there's a very clear trend of failure increasing at low temperatures - in fact, every low temperature launch had had O-ring failures, while very few high-temperature launches had. By being selective in what data you present (accidentally in that case, on purpose in the present case), you can get people to believe precisely the opposite of what is true.

Comment Re: Great idea... But there is a problem... (Score 1) 302

Anyone who can say "only 6000 m/s" with a straight face when talking about post-launch maneuvers has never worked with rocket mass budgets. ;) For a single stage, 6000 m/s with a 340s isp and 0.08 inert mass ratio is an over 10:1 scaling factor (aka, for every 10 kg you launch to LEO you get 1kg payload to your destination). Just 3000 m/s is a nearly 3:1 ratio.

Comment Re: Great idea... But there is a problem... (Score 1) 302

Probably better to get some kind of cloud city working on Earth before attempting to go trans-solar-system with the concept.

That would indeed be part of the development process. It's harder on Earth, mind you - a Landis habitat has to be inflated with heliox on Earth, which is much more expensive and permeation-prone. But such a habitat absolutely can be tested on Earth.

By the altitude Venus' atmosphere is more dense than Earth's, it's also highly corrosive.

The sulfuric acid is quite overstated in the popular imagination. It's more like a bad smog (or more accurately, vog) - several to several dozen milligrams per cubic meter, as noted below (also as noted below, OSHA allows people to breathe up to 1mg/m^3 for an entire 8-hour shift). It's much more of a resource than a problem; design work would be simpler if it were denser, not sparser. Material compatibility is easier to ensure (via fluoropolymers) than the scrubber design aspects are; you have to have high mass flow rates because the sulfuric acid is so sparse.

(That said, there was some - disputed - evidence from Vega that there may sometimes be "rain" on Venus. If that's correct, that'd be quite the blessing for resource collection. It's sad how we don't even know such basics as "does it rain on Venus?" at present)

Jupiter is a little too active for my taste, but perhaps Neptune or Uranus might have some attractive latitudes at which to float a city, assuming you bring your own power sources and don't rely on the sun.

The gas and ice giants are tough. They're very, very far, exceedingly hard to get out of, and because they're predominantly hydrogen (80-96%), the Landis design is right out (you can't live in a spacious envelope, you're stuck in a gondola); the envelope has to be hot hydrogen (heated with a lot of energy, because you lose it quickly on those scales). The gas and ice giants also have the wrong ratios of temperature to pressure - too much pressure relative to temperature. Plus, much less diverse gaseous mineral resources, and (effectively) no surface mineral resources at all. And of course as you note, little light. Venus is far better in virtually every respect. Its right next door, the easiest planet to get to, a great location from an orbital dynamics perspective, and it has everything.

Comment Re: Great idea... But there is a problem... (Score 1) 302

I'm with a group called Venus Labs; we'll have our first book out later this year. :) Materials compatibility is a big topic therein. Thankfully, there are a lot of polymers that have good resistance to Venus's environmental conditions (particularly fluoropolymers, although minimizing coating fluorine content is important for ISRU because hydrogen fluoride is a lot less common than hydrogen chloride and sulfuric acid - so for example PCTFE or PVF would be preferable to, for an example, FEP). The sulfuric acid mist isn't actually very concentrated from a particle density perspective - visibility is a couple kilometers. The mist is a couple to several dozen grams per cubic meter, depending on the altitude, latitude, time, etc (by comparison, OSHA allows people to breathe up to 1 mg/m for an 8-hour work shift). But it is concentrated from a molar perspective - on Earth, H2SO4 mists self-dilute with atmospheric water vapour.

Comment Re: Great idea... But there is a problem... (Score 2) 302

"That book"?

Why Venus? Venus has the most Earthlike environment in the solar system outside Earth. High latitudes in the middle cloud layer have Earthlike temperatures, pressures, gravity, sufficient radiation shielding, ample light, and diverse resources already gas phase and only needing to be run through a scrubber to give you feedstocks (even iron, in the form of iron chlorides - estimated at about 1% of the mass of the sulfuric acid - which, by the way, thermally decomposes in the presence of a catalyst to release water and oxygen). Concerning orbital mechanics, Venus ascent stages are of course harder than Mars, but apart from that, it's in a much more favorable spot concerning orbital mechanics, with a much greater Oberth effect and much more frequent launch windows; it can be easier to get payloads to Mars from Venus than from Earth (and can even get gravity assists from Earth). Beyond the abundant solar power, there's also abundant wind power. Normal Earth air is a lifting gas. Unlike a Mars habitat which is a cramped pressure vessel, a Venus habitat is an expansive, open, bright area, full of plants and life. If you don't like someone, go hang your room elsewhere in the envelope, potentially even hundreds of meters away. Bored? Jump into the safety netting; the scale indoors is so big you can basically do indoor skydiving.

As for learning, Venus has vastly more unknown than Mars. Venus is our twin, and the question as to why it ended up the way it did and Earth didn't is one of the great questions in planetary geology. Venus used to have oceans like Earth. Yet today its surface has become this alien place, a veritable natural refinery that bakes and erodes minerals out of the surface and precipitates them out in the clouds. The whole planetary surface, or nearly so, resurfaced itself about 500 million years ago. We have no idea why. Can Earthlike planets just up and do this? If so that's a very disturbing concept. it has the longest river in the solar system - we have no clue what carved it. The best theories are really weird, like natrocarbonatites - super-rare low-temperature lavas that look like oil, flow like water, and glow crimson at night. It has lightning, but we can't seem to find it. It seems to be the second most volcanically active place in the solar system (after Io) but we've never positively confirmed an eruption. There's a huge amount that our planetary models just can't explain. Why doesn't it have an intrinsic magnetic field? Even with its slow rotation speed, dynamo theory says it should; it doesn't. Where's its mercury? Chemical models say that there should be 3 1/2 orders of more in the clouds than the upper detection limits of the probes thusfar constrained it to. What are the strange radar reflective frosts / snows in the highlands? Pyrite? Galena? Tellurium? There seems to be more than one type, too. I could go on for pages and pages here. And there's vastly more reason to have humans present for exploration on Venus, because given the surface conditions, latency for controlling robotic probes is very important - unlike Mars, where communications "downtime" for rovers just gives them more time to charge in the weak sun. And you don't have to worry about degeneration due to low gravity like you do on Mars.

The surface, while hostile, is absolutely accessible. The Soviets had a lot better success probing the surface of Venus than they had Mars. The basic design is very simple: metal shell. insulation, and a material that absorbs heat through a phase change; it can easily buy you a couple hours. Tech developed by the Soviets in the 1960s. It's been determined that you could actually shoot a hollow titanium sphere at Venus, without any kind of heat shield or parachute, and it'd reach the surface intact; that nice "fluffy" atmosphere goes a long way. On Mars you have to have controlled propulsive landings onto rough terrain with little to slow you down - something that continues to randomly kill landers. The surface air on Venus is dense enough to allow you to dredge minerals off the surface.. You can get off the surface, too, with phase change or bellows balloons. The surface is even accessible for humans, and not just in "submersible"-style vehicles - through atmospheric diving suits like are used for deep sea human diving. NASA was developing such "hard suits" for the Apollo program and a bit after - the AX series. They went with soft suits because they're lighter, but hard suits have better mobility. And more to the point, on Venus with such a suit and a bellows balloon, a person could literally fly - floating up, and gliding down with little wings in controlled flight at up to a couple dozen meters per second.

Comment Re: Great idea... But there is a problem... (Score 1) 302

What is the cost of launching a Mars vehicle directly from Earth?

$7k/kg by Falcon Heavy pricing. Would you rather a different launch system?

Insanely high

Not really. But the problem is your "lowering prices" standards involves having to send things into to an entirely different gravity well (consumables), and landed propulsively, so that other different things can then be launched from said gravity well.

And it has diminishing returns

Your proposal, absolutely.

From Earth, there are no diminishing returns whatsoever. Just the opposite - the more you launch, the cheaper it gets per kg.

There is no practical way to launch a large enough manned vehicle for Mars

One: completely and utterly false. There are a huge number of different proposals for this, all of them technologically feasible.

Two: your counterproposal involves doing the same for the moon, and then doing constant resupply so that they can build things that require an entire industrial base there. It's an absurdity.

Let's take a look at the Falcon Heavy heavy lift vehicle [] which is one of the heaviest available right now. The payload to Mars is about 13,000 kg. That is about the weight of 1 ISS module.


No, seriously, and? Just ignoring that you can launch to LEO, including transfer stages, and this you actually can launch over 50 tonne segments, is your notion that humans can't build things in space? If not, walk outside tonight when the ISS is due to pass overhead, and look up.

The cost per launch is $90m. Want five launches to build it? Ten? Fifty? You're still a fraction of the cost of establishing the sort of industrial infrastructure needed on the moon to support rocket launches, which in turn is still going to cost more than from the Earth due to the cost of said infrastructure's imports.

Have you ever thought why no NASA missions to outer space has been refueld?

You mean like the ISS?

The ISS station gets refueled all the time but not probes. Why is that?

Because it's cheaper to just build things on Earth and launch them, exactly the point I've been trying to get you to understand this whole time. Doing things in space increases the cost, and the further you are from Earth, the greater that cost is. Work in LEO is expensive because everything requires consumables that must be launched (humans in particular). Work on the moon is vastly moreso because it requires vastly more delta-V to get there. You're wanting to do the vast majority of the work at a place where costs make LEO look like a bargain. Work that can't even be done without developing a whole industrial base to begin with.

By your logic, NASA has no plans for Mars either.

Incorrect, and an absurd statement to make. The "Journey To Mars" program is the core of NASA's focus. (If it wasn't, nobody would ever put MOXIE on Mars 2020. ;) )

This is getting absurd. If anyone else wants to talk to this person (who actually goes by the name "UnknowingFool" - almost starting to wonder if this is trolling), go ahead - I'm out.

Comment Re: Great idea... But there is a problem... (Score 1) 302

Nowhere did I say that NASA needs to rebuild and entire installation; however, in terms of fuel cost it is much easier to launch from the Earth to the moon then refuel at the moon

Implicit in saying that is the premise that the moon has an industrial base, because you don't make fuel and launch rockets without an industrial base. And an industrial base means dependency chains. And even importing a very small fraction of the amount from Earth to fill gaps in their dependency chains that they launch from the surface would easily price them out of the market. Never mind the absurd capital costs you have to amortize.

Current NASA plans have the moon as a refueling point

NASA has no plans for a lunar refueling point. It is not part of any actively-being-worked-towards timeline. They've posited the concept before, but they've posited a million fanciful things.

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