How To Get Back To the Moon In 4 Years -- This Time To Stay (scientificamerican.com)

Scientific American describes "a way to get to the Moon and to stay there permanently...to begin this process immediately and to achieve moon landings in less than four years." It starts by abandoning NASA's expensive Space Launch System and Orion capsule, and spending the money saved on private-industry efforts like Elon Musk's SpaceX and Robert Bigelow's Bigelow Aerospace. schwit1 quotes their report: Musk's rockets -- the Falcon and the soon-to-be-launched Falcon Heavy -- are built to take off and land. So far their landing capabilities have been used to ease them down on earth. But the same technology, with a few tweaks, gives them the ability to land payloads on the surface of the Moon. Including humans. What's more, SpaceX's upcoming seven-passenger Dragon 2 capsule has already demonstrated its ability to gentle itself down to earth's surface. In other words, with a few modifications and equipment additions, Falcon rockets and Dragon capsules could be made Moon-ready...

Major segments of the space community want every future landing to add to a permanent infrastructure in the sky. And that's within our grasp thanks to Robert Bigelow... Since the spring of 2016, Bigelow, a real estate developer and founder of the Budget Suites of America hotel chain, has had an inflatable habitat acting as a spare room at the International Space Station 220 miles above your head and mine. And Bigelow's been developing something far more ambitious -- an inflatable Moon Base, that would use three of his 330-cubic-meter B330 modules.
The article calls Jeff Bezos's Blue Origin rockets "a wild car" which could also land passengers and cargo on the moon and suggests NASA would be better off funding things like lunar-surface refueling stations, lunar construction equipment, and "devices to turn lunar ice into rocket fuel, drinkable water, and breathable oxygen."

Comments

Rockets are too expensive

[KeithCu]

With rockets it is still $100K - $1M per pound to get to the moon. We need a space elevator.

Re:Rockets are too expensive

[h33t l4x0r]

No we need a space escalator. Much more presidential.

Re:Rockets are too expensive

[Bruce Perens]

And a space elevator, of course, would only cost about a Trillion, and there's this little problem of it hitting something (we'd have to make Earth Orbit absolutely pristine and keep it that way) and there's a problem with the kinetic energy if it falls down. Sort of like having many atom bombs go off.

Maybe someday. But right now making rockets as cheap as they can be is a better idea. It's only $200K to fuel up a Falcon 9. We don't get the whole thing back in working order yet, but that would be a lot easier than making a space elevator.

Re:Rockets are too expensive

[KeithCu]

There are other detailed estimates for a space elevator that are around $10 billion. The people who throw around $1 trillion are trying to pick a number so big it prevents people from considering the feasibility. You definitely won't find any detailed breakdown that leads to something so insane.
Brad Edwards book covers all of the problem scenarios you laid out. He explains why it wouldn't be catastrophic if it did fall apart, and what needs to be done to prevent it. I agree we do need to make space more pristine, but we can clean things up, move the tether around, and repair it. It's all engineering work. This could have started in 1991, when carbon nanotubes were first discovered.

Re: Rockets are too expensive

[KeithCu]

You obviously have done very little reading about the space elevator, AC. It's not a building, it's a tether. How much would it cost to make 50 thousand miles of 3-foot, paper-thin steel? It's not strong enough, but it gives you some idea of costs more than what you are throwing around.

The key to making it cheap is the bootstrapping mechanism that Edwards described in his book. What you do is launch into orbit just a seed string, and the first climbers will be small and actually strengthen the ribbon.

Re: Rockets are too expensive

[lgw]

Half the energy to obit at GEO comes from lateral acceleration. A space elevator would be a giant pendulum. And not a nice freshman-physics harmonic oscillator, but a nasty chaotic system with multiple modes of vibration. The energy stored in the system would increase with every payload until it destroyed itself, because there's no way to shed that unwanted energy - minimal friction, trivial air resistance, and so on.

Re:Rockets are too expensive

[ShanghaiBill]

And a space elevator, of course, would only cost about a Trillion

Since the material to build it doesn't exist yet, estimates of the cost seem a bit premature.

and there's this little problem of it hitting something

Most designs are for many fibers in parallel. So in an impact you would lose one out of N. Other designs are for a wide ribbon. Nobody is proposing a cylindrical pillar.

there's a problem with the kinetic energy if it falls down.

Since it has a counterweight, why would it "fall down" rather than "float up"?

Sort of like having many atom bombs go off.

Except it is 25,000 miles long, so it wouldn't all go off at once. It would be like a ribbon falling into the atmosphere. It would burn up 60 km up, and unlike a nuke, there would be no radiation or EMP. Chelyabinsk killed zero people, and that happened over land. A space elevator would have its base at sea near the equator.

Re: Rockets are too expensive

[joh]

They only need fins because they have to steer a lot due to the inconsistencies of the atmosphere (wind and unknown pressure details). On the moon you need no fins, you can just aim a precise trajectory all the way down to the landing point.

Re:Rockets are too expensive

[Rei]

Quite true. The materials technology required is about two orders of magnitude away from actual materials technology, for starters. And among the countless other problems with space elevators, they're not actually all that efficient. Laser power beaming over those distances works out to single-digit transfer efficiencies, and microwave power beaming even less (microwave power beaming to space can be efficient, but only if the receiving antenna is huge). And no, you can't regularly hang things or run power wires up a space elevator - the mass of the cable has to be vanishingly small.

Active-suspended structures, such as Lofstrom loops, are a much better choice. Power transfer efficiency can be greater than 50% and current materials technology should be sufficient. They can also be designed to shoot payloads into any orbit (unlike space elevators), and work independent of the properties of the body in question, as well as having far greater throughput per unit mass. There's really no reason to choose a space elevator over a Lofstrom loop.

Re:Rockets are too expensive

[Rei]

I have read the book, and it's an absurd degree of wishful thinking. Just ignoring the huge number of things that they just gloss over or omit outright, the materials technology they're talking about is about two orders of magnitude away from what we actually have, and might even be physically impossible. Measurements of individual carbon nanotubes (let alone bundles, let alone bulk fibres) don't approach the strengths being talked about there. Colossal carbon tube does better on an individual tube basis, but again, we're nowhere even close to the materials tech required. And for what? For a massive, very low throughput, tiny safety margin, most-failure-modes-unaccounted-for, low-power-efficiency means of access to space? Colour me unimpressed.

If you want something better, I recommend looking into Lofstrom loops (launch loops). Current materials tech, high efficiency, high throughput per unit mass, no orbit restrictions, and works even on tidally locked bodies.

Re: Rockets are too expensive

[Type44Q]

The fins clearly provide stability and guidance at higher, atmospheric speeds but their usefulness is likely in proportion to their speed [through atmosphere]... In any case, you make a good point; perhaps the Moon's far-shallower gravity well would make that less of an issue. One thing's for sure, however: Musk's rockets are presumably designed to retrobrake and land nearly empty of fuel and free from top-heavy upper stages containing luna-bound cargo...

Not Happening Anytime Soon

[Anonymous Coward]

The cost of a manned moon base was and is astronomical. Moreover, there remain substantial unsolved problems, particularly with regard to moon dust which is razor sharp, microscopic and gets into everything, quickly degrading gaskets, lenses and other dust sensitive surfaces. Finally, there's nothing there valuable enough to justify the expense at this time.

Re:Not Happening Anytime Soon

[Rei]

That's the biggest concern I have. People tire of ongoing expenses. ISS seemed neat at first; now everyone hates it. Why would a moon base fare differently?

Long-term presences in space need to very quickly cut ties with earth, on order of greatest resource dependencies down to smallest resource dependencies. Aka, first things like oxygen, propellant, etc, then to industrial chemicals, of increasingly smaller quantities, with increasingly diversified manufacturing facilities, with very complex/low volume chemical feedstocks and manufacturing processes coming last. Cutting all ties is a process that would take centuries. But you can start with the low hanging fruit, bit by bit, and keep stockpiles of everything needed for maintenance that you can't produce locally.

Unfortunately, running counter to this is expansion. Because if you double the size of your operations, you also double your resource demands. So you need to improve resource independence at a faster rate than you grow.

Part of the problem with the moon is that it's just not a great place for ISRU. Volatiles are rare. We've never even sampled any moon that aren't depleted in volatiles, although there's some data to suggest that various volatiles might be scattered in permanently shaded areas (all of them, in the same place? That's a good question). Surface mineral diversity is limited - primarily light, non-volatile elements. Oxygen is at least widely abundant, but locked up tightly. And while the moon offers short transit times, it's surprisingly not that advantageous concerning delta-V. You can't aerocapture there, landing is fully powered (no parachute deceleration), and to get there you have to already be on such a high apogee orbit that it's not much more energy to go into a Mars transfer. Gravity is less and night is two days long. There are a couple "maybe" peaks of eternal light, but that doesn't mean that they're colocated with volatiles; the last I looked into it it looked like the closest suggested find of water was dozens of kilometers away from the nearest such peak, which would be quite the commute (and thus low throughput / high wear).

The moon is certainly the "cautious" option; emergency returns / resupplies are easy there, and communication fast. Its main value appears to be a testing ground for systems while minimizing risk. But it's not a very appealing place from a settlement perspective.

Of course, I prefer Venus to Mars, but that's neither here nor there ;) I'd like to see a parallel program for both, as the same sort of booster and transfer stage can be used for both, so it's only habitat / ascent stage development costs that are doubled. And once you get past the differences in feedstock sources, production industrial processes converge (Venus advantaged by the higher power availability and easier ability to get rid of heat - excepting in the case of cryogenics, where Mars holds the advantage)

No Dragon 2 Soft Landing Yet

[Bruce Perens]

Dragon 2 isn't built yet. The escape test was a boilerplate capsule more like a Dragon 1 than 2. Dragon 2 has not demonstrated a soft landing, because it's not built yet. That was the Falcon 9 first stage.

Also, you can't get Dragon 2 down to the Moon and back up on it's own. Not enough delta-V. You would need to have Dragon ride on top of something that can hold enough fuel. Like a larger version of the Apollo Service Module.

The Command/Service module was originally intended to land on the moon and return without the LEM, before NASA bought the LEM concept, and was overpowered for the mission it got. Dragon is larger and heavier, but a lunar landing one would probably look a lot like an Apollo Command and Service module, and legs.

And yeah, Orion: I'm Not on Board. Big expensive obsolete rocket with no mission that makes sense.

But good luck getting Elon Musk to focus on the practical and eminently desirable target of the Moon. He isn't interested. It's only Mars for Elon.

I try not to watch all of the Mars Colonial Transport speculation. Falcon 9 and Dragon are great, and they're here, and we could do so much with them.

Re:No Dragon 2 Soft Landing Yet

[khallow]

But good luck getting Elon Musk to focus on the practical and eminently desirable target of the Moon. He isn't interested. It's only Mars for Elon.

He's interested in paying customers. Maybe someone who is interested in lunar development should buy some Falcon 9 or Heavy launches and just make it happen?

Re: No Dragon 2 Soft Landing Yet

[Rei]

What, exactly, is the purpose of hanging in the clouds of Venus ?

What, exactly is the purpose of hanging out in the near-vacuum of Mars?
What, exactly, is the purpose of life?

If you don't agree with the merits of the human race becoming a starfaring civilization centuries from now based on investments made today in getting the ball rolling today, I'm not going to debate that with you. But if you agree with that, then the whole point in expanding offworld is to develop into a multiplanetary species, where demand drives down launch costs and we learn, step by step, to make everything that we need in offworld environments and to become adept at the multi-month journeys between planets. At first, it's a sunk cost. With time, it's increasingly supported by trade. And after long periods of time, it brings the immense resources beyond our planet into our grasp.

If you want to talk about economics on Venus, here's a few for you.

* Power is immensely abundant. Many technologies that we employ are basically energy costs - to pick an example, isotope enrichment. So once the higher marginal capital cost for doing things on Venus becomes overtaken by the greater energy availability, Venus becomes the logical place to conduct such activities.

* Deuterium levels are ~240 times higher than on Earth. So depending on the level of enrichment you need and the means by which you return it, if you can return goods for somewhere in the "couple thousand to several tens of thousands of dollars per kilogram" range, it's profitable. Deuterium recovery can be rendered an inherent part of nighttime fuel cell power storage, since electrolysis has an excellent enrichment factor.

* Venus's lavas appear to be highly differentiated, and there's a great degree of chemical weathering and atmospheric processing, which can be another resource enrichment process. So concentrations of high value ores far greater than are found on Earth are not unrealistic. There are a couple dozen elements whose values are worth exporting at realistic launch costs several decades from now.

* Even simple rocks from offworld have great value (collectors, luxury goods, etc). It's not theoretical - people really do pay huge sums for offworld items. Their value will of course depend first the abundance of their export (if you export 100kg per year, you can sell for 10x more per kg than if you export 10000kg per year, which you can sell for 10x more per kg than if you export 1000000kg per year...). If you're selling in small quantities, the value could be in the millions of dollars per kilogram. Venus's surface atmosphere is dense enough that you can outright dredge loose rocks.

* The size of the market and sensitivity to export quantity also depends on their aesthetics (aka, moving more from the collectors market into the larger luxury goods market). This means minerals that are durable and aesthetically pleasing. What we've sampled so far of Venus's surface fits that bill - gabbro (sold as "black granite" - large crystalled, dark, hard rock, forms excellent slabs), anorthosite (rare on Earth, often associated with labradorite, which is an iridescent bluish-purple semiprecious to precious mineral), troctolite (rare, olivine (peridot)-rich relative of anorthosite and gabbro - looks like this when cut and polished), etc. It's one thing for your typical sheikh or dotcom millionaire to say "my yacht's countertop is made from the finest tuscan marble." It's another to say "my yacht's countertop is from freaking Venus." You're looking at a very large market in the 4 figure/kg range, a reasonable market in the 5 figure/kg range, and a small but decent market in the 6 figure/kg range.

* Venus's apparently high levels of repeated differentiation, in conditions very different from Earth, likely mean that some minerals, including gemstones, that are rare or no

Too soon to say

[Eloking]

As much as I love Elon and his accomplishments, let's not forget that SpaceX reusable launch system's costs to refurbish and relaunch are not demonstrated...yet. Have they forgotten the the Space Shuttle Program already?

Good grief

[Anonymous Coward]

Abandon Ares. Abandon SLS...

SLS is up to 2.5 times the LEO capacity of a Falcon Heavy, which SpaceX has never actually launched. SLS is in a different class. SpaceX might launch a Heavy in 2017, but I personally doubt it; SpaceX has never hesitated to push back dates and they've done exactly that with each new development phase. That's not a knock; they've done well and should continue their pattern. But SLS goes up in 2018 and even that first launch will achieve greater lift capacity than anything SpaceX or its competitors are actually building, never mind the SLS scale out to 130,000kg.

A least Trump doesn't appear to want to kill off SLS. If anything he seems to want to accelerate the program into a manned phase. And I'm pretty sure he doesn't give a warm piss what Scientific American has to say about it, so it looks like this heavy lift system will finally survive US politics.

Re:Good grief

[khallow]

SLS is up to 2.5 times the LEO capacity of a Falcon Heavy, which SpaceX has never actually launched. SLS is in a different class. SpaceX might launch a Heavy in 2017, but I personally doubt it; SpaceX has never hesitated to push back dates and they've done exactly that with each new development phase. That's not a knock; they've done well and should continue their pattern. But SLS goes up in 2018 and even that first launch will achieve greater lift capacity than anything SpaceX or its competitors are actually building, never mind the SLS scale out to 130,000kg.

In other words, NASA might launch an SLS variant this decade, but they probably won't. Funny how your personal doubt fails to extend to NASA which is even more notorious than SpaceX for delaying launches and failing to deliver on a launch vehicle.

No Idea on how valid the alternates are

[Crashmarik]

But it's hard to do worse than NASA's SLS

http://www.thespacereview.com/...

It has been estimated at a per launch cost of 5 billion a shot, and a cost per pound that makes the shuttle look like Amazon Prime.

Re:Not to be a wet blanket...

[DrXym]

I don't really buy the argument that it would be cheaper to go to Mars from the Moon. Any manned Mars mission would likely to be assembled in stages in orbit of the Earth. Much cheaper and less risk than sending those same stages to the moon and assembling them there.

STS has a problem

[joh]

It's not reusable and much too expensive to be flown more often than a few times. It never was anything than a gift to the companies that built the shuttle, so they could continue to supply tanks and solid boosters and hideously expensive engines. The point of it never was getting anything into space, but to keep the same old rivers of money flowing.

Re:and fairy dust and unicorns too!

[Anonymous Coward]

You underestimate engineers. We went from "first flight" to the moon in less than 70 years. We went from "First rocket" that flew 30 feet to the moon landing in about 4 decades.It's JUST AS LIKELY that we'll go from "material with enough tensile strength invented" to "space elevator" in a few decades too.

This is what I like to call the "extrapolation fallacy". People assume that if something is possible, anything is possible.

There are limits in the universe that put upper bounds on what's achievable. At the moment, we're not even sure that it's theoretically possible to create that "material with enough tensile strength". If it turns out it's not, then no amount of engineering will make it reality (disclaimer: I'm an engineer).

It's the same fallacy that people make when they imagine advanced alien races coming up with physics-breaking technologies (FTL, Dyson spheres, ring worlds, teleportation), or when they imagine life inside of stars (it's just too extreme inside there for stable systems to exist, let alone evolve).

Simple. Change the gravitational constant

[Thud457]

phhht, just let them throw away the money building the wall, then when he's out of office, just turn it up on its end. Presto, space elemavator!

Clarke wrote about it in SF

[Geoffrey.landis]

As noted, Clarke did not invent the concept of the space elevator, although he was one of the first two writers to highlight it in science fiction (with Charles Sheffield the other). The concept of the space elevator was invented independently several times, the first time Artsutanov (who only published in Russian), then by Isaacs et al, and then by Pearson.

http://www.isec.org/index.php/10-resources/18-the-history-of-the-space-elevator

Clarke didn't invent the concept of a geosynchronous satellite, either, although he was the first to point out that geosynchronous orbit was an excellent orbit for communications.