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Comment Re: Great idea... But there is a problem... (Score 1) 298

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) 373

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) 373

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 www.siteiveneverheardofbefore.com/newishstuff/hillaryclintonpedophilering.html 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) 298

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) 298

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) 298

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) 298

"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) 298

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 [wikipedia.org] 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.

And?

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) 298

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.

Comment Re: Who cares? (Score 1) 298

So all the water on the moon that could be used as fuel for Mars missions has no value?

I'd love to see your proposal for launching water from the moon to Mars for less than $7k per kilogram. Include all allocation of labour, all feedstocks production, and all consumables, including system maintenance.

The reason we launch from the Earth is Earth is where our industrial production infrastructure is. And even if you have to import just a couple percent to the Moon of the mass that you could launch from the Moon in payload (aka a highly evolved industrial base), you've blown your budget. Just ignoring that the needs of Mars most definitely aren't water. It's habitats, vehicles, and industrial / manufacturing hardware. Have fun trying to produce that sort of stuff on the moon.

Comment Re:How much to re-create Apollo? (Score 1) 298

As you note, the tooling for Apollo doesn't exist. The suppliers don't exist. Some parts of the design don't exist any more, and that which does is just on paper. Everything would have to be started over in terms of modern CAD diagrams, full testing, etc. It would be more expensive to recreate Apollo than to make a new system with better performance. Today we have better alloys, better performance designs, more knowledge. And we do have infrastructure and suppliers that exist today, so it makes much more sense to make use of their capabilities than to recreate that which existed in the 1960s.

Your post seems premised on the notion that finding a way to make a big rocket is hard. It's not. There is no shortage of ways to come up with arrangements to reach the moon. The hard part is the low level engineering and testing, both at the component level and integration level. And we don't get that by going with Apollo. We actually lose in that regard, versus going with more modern systems.

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