Tuesday, August 6, 2019

Tuesday Tweets











There were those like Josh Marshall who got most things right in 2016, those like Nate Silver who went from mostly wrong to mostly right, and those like Nate Cohn who were pretty consistently wrong. I'm not sure why we should still be listening to the third group.



This goes to the heart of the problem with Chait's education writings. His heart's in the right place and he cares deeply but his knowledge of the field is spotty at best. Among actual educators, this issue has been widely discussed for years.













Monday, August 5, 2019

Persistence of Narrative -- Netflix edition

One of the interesting things about the reaction to the recent bad news at Netflix is the way that the bulls are sticking not just with the company but with the narrative.
"The company appears to operate in a virtuous cycle, as the larger their subscriber base grows ... the more they can spend on original content, which increases the potential target market for their service," said Jeffrey Wlodarczak, an analyst with Pivotal Research Group, in a report after its recent earnings release.

Wlodarczak added that Netflix may remain a hit with consumers because it has continued to defy calls to launch a service with commercials, even though an ad-supported plan could be cheaper. He dubbed Netflix "an increasingly compelling unique entertainment experience on virtually any device."
Let's start with the rather bizarre claim that Netflix will "remain a hit with consumers" because it refused to launch a second ad-supported service. Taken on its own, the reasoning is hard to follow -- a second service might not be profitable but there's no reason it would turn off members -- but it also flies in the face of recent developments in the industry. The free-with-commercials model has had a big resurgence with major players like PlutoTV and Amazon's Freedive entering the streaming space and Terrestrial Super-Stations like MeTV posting extraordinary profits.

The claim makes no sense in terms of business, but it makes great sense in terms of story. Ads were the old way. Netflix is the disruptor. The success of the disruptor is an essential part of our modern mythology. You don't stop believing just because the evidence turns against you.

Even more central to the Netflix narrative was the role of original content. That was the competitive advantage, the secret of their success. "Secret" turned out to be something of an operative word. For years,  the company managed to keep actual numbers largely out of the discourse. Recently though, the picture has started  to fill in. We now know that, despite billions in production and billions more pushing these shows, originals account for only a quarter of the hours viewed and many of those shows don't exactly belong to Netflix.


Friday, August 2, 2019

11 songs that more people should know -- Special Guest Blogger

[I had to delay today's  post, so I asked an old friend (and pop culture maven) to suggest a few undeservedly obscure songs to kick off the weekend. Not actually what I meant by a "few" but I'm not complaining.]

Hello! I'm Brian Phillips and here are 11 songs that you may not know, but really should. If you like an eclectic mix of music, take a listen to my show, The Electro-Phonic Sound of Brian Phillips at rockinradio.com

1. The Crew was a positively dismal show, but fortunately, the producers had the good sense to hire Wendy Coleman and Lisa Melvoin, late of Prince and the Revolution, to do the very catchy theme. If you continue to watch...you have been warned.


2. "Treemonisha" was a triumph for the composer Scott Joplin, albeit posthumously. Sadly his opera, was never fully staged in his lifetime, but when "The Sting", which made extensive use of his music, it triggered a full-blown revival and the opera was finally staged in the 1970's. This is the finale and the oft-used Joplin quote applies here: "One should never play Ragtime fast". This is the "Real Slow Drag"


3.  From Houston, TX, it's Lee Alexander! This was recorded in 2006. This may be his only album.


4. Tribe was a band out of Boston and they recorded two albums before splitting up. They never got very popular outside of their hometown, even with the backing of Warner Brothers Records. There aren't as many great Rock songs in waltz time, but this is a good one


5. The Blue Ribbon Syncopators, a band out of Buffalo, NY who made six known recordings. Banjo is prominent here and, like the tuba, was mostly gone from Jazz by the 1930's


6. This is quite a lot of noise from this NY band, led by the chief songwriter, Joe Docko. Docko was 16 and one can only wonder what his music career would have been, if the Mystic Tide had any significant success. The highlight of this song are the two vocal lines. Docko destroyed all of his remaining Mystic Tide records, so what is out in the wild is all that is left.


7. Looking for the Beagles? For a time, some people were. This was a cartoon by Total Television, the same folks that made Underdog. It wasn't a hit and it was thought to be lost until recently. Surprisingly there was a soundtrack LP from the show, and it has become a collector's item, not only because of its rarity, but the music is quite good.



8. Joe Maphis was one of those fellows who went to the talent store and stayed longer than most. Don't believe me? Take a look at this and watch what he does at 2:00:


9. This is Kenneth "Thumbs" Carllile. You'll see why they called him that when you watch this. He was a sideman with Roger Miller for a number of years and released several albums under his own name.


10.  Oscar Coleman, aka Bo Dudley, is the leader of this session, but what makes this song great is the incendiary pedal steel guitar of Freddie Roulette, who was a sideman to Earl Hooker and Johnny "Big Moose" Walker, and he also recorded as a leader later in his career.


11. Have a good weekend everyone! I am not quite sure why this wasn't a hit. Here are the Loved Ones from California.

Thursday, August 1, 2019

What Nate silver has in common with Bob Dylan, Tom Wolfe, and Pauline Kael.

I don't remember if I ever got around to it, but for years I've been meaning to write an Andrew Gelman style class post on people whose work is great but whose imitators drag down the field.

I go back and forth on Bob Dylan here. There is no counting how many coffee house hacks have convinced themselves that the obscure lyrics they are croaking out are the next Tangled Up In Blue. On the other hand, a lot of brilliant artists have done some of their best work inspired by Dylan.

With Tom Wolfe and Pauline Kael, however, the divide in quality between the originals and the imitators is much more sharp. For more than 50 years now, we have suffered through journalists and critics who have annoyingly affected the tics and mannerisms of both writers, while having none of the talent or insight and being completely unwilling to put in the hard work of research and revision that made Wolfe and Kael so formidable.

I don't want to oversell Nate Silver at this point (he's no Bob Dylan) but he deserves great credit for his Innovations in the way we cover politics. He saw the fundamental problem with remarkable clarity and understood the appropriate level of complexity needed for a solution. As a statistician, he has considerable limitations. When he strays too far from his areas of expertise such as when he writes about climate models, the dunning-kruger effect has a tendency to come down hard, but he does have a natural talent and an all too rare capacity to learn from his mistakes.

His success unfortunately has inspired a wave of data journalists who are more often than not terrible at their jobs. It turns out that being enamored with data and yet being bad statistics is often worse than ignoring data entirely.

Wednesday, July 31, 2019

Any conversation about electability has got to start with the fact that a white male has not won the popular vote since 2004.

The electoral discussion among pundits and data journalists has been taking some especially silly turns of late and before the bullshit accumulates to the same dangerous level it did in 2016, we need to step back and address the bad definitions, absurd assumptions, and muddled thinking before it gets too deep.

We should probably start with the idea electability. While we can argue about the exact definition, it should not mean likely to be elected and it absolutely cannot mean will be elected.

Any productive definition of electability has got to be based on the notion of having reasonable prospect of winning. With this in mind, it is ridiculous to argue that Hillary Clinton was not electable. Lots of things had to break Trump's way for him to win the election and, while we can never say for certain what repeated runs of the simulation would show, there is no way to claim that we would have gotten the same outcome the vast majority of the time.

This leads us to a related dangerous and embarrassing trend, the unmooring of votes and outcomes. This is part of a larger genre of bad data journalism that tries to argue that relationships which are strongly correlated and even causal are unrelated because they are not deterministic and/or linear. In this world, profit or even potential profit is not relevant when discussing a startup's success. Diet and exercise have no effect on weight loss. With a little digging you can undoubtedly come up with numerous other examples.

The person who wins the popular vote may not win the electoral college, but unless you have a remarkably strong argument to the contrary, that is the way that smart money should bet.

Tuesday, July 30, 2019

Tuesday Tweets -- “rapid unplanned disassembly“ edition








I think Lee is underplaying the role that the huge, broad-based spikes in the late 19th Century and post-war era were in forming the idea of the exponential progress curve (and how resilient the belief has been in the face of conflicting data). 



I've been meaning to do a post on indicators that the standard political model may be heading for a rough patch.


Also want to come back to this.

Silver is having a good run.



Read this.



Monday, July 29, 2019

Taking on the votes-don't-matter meme -- the EC doesn't always follow the popular vote, but that's the way the smart money should bet

And once again we are in the silly season.

First off, a quick disclaimer: You can never reasonably dismiss an incumbent president's chances of being reelected. No matter how poor the prospects look, there are always plausible paths to victory. Not taking Trump seriously  would be irresponsible, but much of what we're hearing from the other extreme are just as foolish possibly more dangerous (the combination of defeatism, panic and bad reasoning seldom works out well).

 Popular variations on the all-is-lost theme include:

"Trump is unstoppable unless the Democrats move to the right/move to the left/embrace my pet issue."

"Trump is actually pursuing a cunning plan that will insure victory."

"The popular vote doesn't matter. The electoral college went the wrong way two out of the last five elections."

 Let's take that last one. The EC is a bad system that should have been scrapped long ago, but at least from a historical perspective, how likely are these undemocratic outcomes?

 For starters, we need to be very careful with our terms. There is a subtle but absolutely fundamental distinction to be made between winning the presidency despite losing the popular vote and winning the Electoral College despite losing the popular vote. In 2016, there is no question that the popular vote went one way and the Electoral College went another. In 2000, however, the picture is much murkier.

When we talk about a split between the popular vote and the Electoral College we mean that, given a reasonably accurate count, the all-or-nothing allotment of votes and the minimum delegate rule for small states will cause the Electoral College totals to go in a different direction that the popular vote.

There is always a certain amount of fuzziness when dealing with ballots. There might be a very slight chance that Al Gore did not win the popular vote. There is a very good chance that he did win the electoral college. Once again, I want to be very clear on this point. I'm not talking about who was awarded the delegates. I'm talking about who would have gotten them had there been a properly conducted  counting of the votes in Florida.

We've seen a recent wave of data journalist making bad distributional arguments about the implications of the Electoral College. Most of these arguments use Al Gore as an example despite the fact he does not at all illustrate their point, since who won Florida (and therefore the EC) is very much a disputed point).

If you remove Gore as an example, you have to go all the way back to 1888 to find another. This does not mean that this won't happen again for another hundred plus years. It does not mean that we don't need to worry about this in 2020. It does not even mean that a split between popular and electoral votes isn't The New Normal. What it does mean is that historically there is an extremely high correlation between winning the popular vote and winning the Electoral College.

Just for the record, the undermining of democracy by the conservative movement, particularly through voter suppression and under-representation, is perhaps my number one issue, even more than climate change and income inequality. I am very worried about gerrymandering and voter ID laws and somewhat concerned about the Senate, but the Electoral College, while not defensible, is way down on my list.

Friday, July 26, 2019

Family Friendly?

This is Joseph.

This tweet makes an excellent point:



The context was the cost of summer camps when you have two working parents, without anywhere near enough holidays to cover the summer.  This has to be one of the odd contradictions of modern thinking; I first noticed in in Ayn Rand's book "Atlas Shrugged" where she glossed over the role of children in a hyper-capitalist society.  While not everyone is a fan of Ayn Rand, it was an early sign of a fault point in the individualist culture we have created. 

The problem is that we can't really decide on two things.  One, is the basic unit of humanity individuals or families?  This isn't meant to be exclusionary, but simply to point out that humanity, as a project, requires new humans so if there is a commitment to the species they have to come from somewhere.  I don't want to say how these come together -- family is a very diverse entity -- but they are real mechanisms for child rearing.

Two, is the social contract that Western Democracies have created is about previous generations being transferred wealth in their old age from upcoming generations.  This works best when there is a continuing flow of upcoming generations and that requires some investment in the future as well. 

I am not sure about the solutions, but I am pretty sure that the solution set does not include seeing children as expensive consumer goods. 

Wonder when they stopped running Thunderbirds reruns in South Africa.

Listening to this, I can't help but try  and reconstruct the conversations he had with the actual engineers who tried to explain these ideas to him. He gets most of the phrases right but there's no indication he understands the challenges involved in what he's talking about.






Personally, I want to see him add one of these pilot slides.










Thursday, July 25, 2019

Trickle-down innovation

This is Joseph


I think that this might be the single worst argument in health care today:
The slowdown in pharmaceutical innovation is widely acknowledged, well-documented, and deeply troubling. Most Americans have health insurance. Most Americans are able to get care if they need it. What matters at the point of crisis, then, isn’t just whether someone is covered, but what that coverage can buy. The best insurance in the world won’t save us if our antibiotics fall behind drug-resistant bacteria.
This is particularly pressing for Democrats because the best argument against centralized price setting is that it will slow innovation. So what plans do Democrats have to boost innovation in the health care space? Sanders, for his part, has an interesting idea to use prizes to generate new pathways for pharmaceutical development, but he’s one of the only Democrats with any kind of plan along these lines, and he does
First, even with the current system we are seeing a slow down in innovation.  There is an assumption that that isn't driven by it being easier to rent-seek with current than to come up with new ones.  Or by intrinsic limitations in what low hanging fruit might be left.

Second, the system is actually poorly designed for the example.  Antibiotics are always going to be less profitable than chronic use drugs.  Maybe the slower pace of development is because of the current system that focuses rewards elsewhere?

Third, isn't this the same argument as "trickle down economics"?  If we make health care CEO's rich then others will also seek to become rich and that will drive innovation.  How did that work with economics? 

The US spends twice as much GDP per person as the UK.  The difference between the two systems is about 8% of GDP.  US GDP is around 20,000 billion dollars, so 8% of that would be 1,600 billion.  The NIH budget is around 40 billion.  Let's spend only half of that on research -- I wonder what endless productive NIH could do with a 840 billion dollar budget to drive medical innovation? 

And this is with me not even really trying -- just thinking off of the top of my head.  I think we should be careful with the assumption that innovation by industry is all about improving care.  Some is and there are dedicated people in industry who work hard to help patients.  But some of this is clearly rent-seeking and profit taking.  It's not clear if we could redo the system that we couldn't save money AND be more innovative. 

Just a thought.

Wednesday, July 24, 2019

The Hype Economy runs on faith -- more on Netflix


I was going to run something on this Bloomberg piece, then life got busy and a few weeks passed and soon a number of other posts (including some about Netflix) were demanding to be written. Then this happened and the following seemed too relevant to put off. [emphasis added]
Just the same, Netflix has been producing more on its own. The company will release 1,000-plus pieces of original programming this year. By the time “The Office” deal ends, Netflix will have at least 3,000 new programs in its library and likely surpass 200 million subscribers worldwide.

“People are missing it,” said [Michael Nathanson, an analyst at MoffettNathanson LLC]. “The loss of back titles will not kill Netflix or slow subscriber growth. It just forces them to make more original content.”
There is no rational argument for this position. Netflix is in the process of losing the shows behind roughly three quarters of its viewer-hours. It is maxed out on production without clear ownership of many of its most popular originals (such as She-Ra). It is spending at an unsustainable pace. It's about to fall into the ultimate competitive wood chipper.

Faith-based investing can keep things going a long time, but eventually reality-based results make doubter of us all.

Tuesday, July 23, 2019

Tuesday Tweets -- One Small Step



















 


Monday, July 22, 2019

Netflix represents the overlap of the two great traditions of creative accounting-- Hollywood and Silicon Valley

[I scheduled this a few days ago. Eventful days.]

Since writing this, I've run the story past a number of people who have worked with this kind of consumer data at large companies, and every one of them has had the same reaction. All of them suggested that Netflix was tracking these numbers; it just didn't want anyone to know what they said. I'm also coming around to that conclusion.

I have a feeling that Netflix's transparency is about to become a bigger part of this story.

Monday, October 20, 2014

The myth of a data-driven Netflix

There's been a lot of talk about Netflix stock this week (usually with words like "plummet"), but a big part of the story has largely gone unnoticed, probably in part because it involves statistics.

As mentioned before, some aspects of the Netflix narrative such as the company building and HBO type content library, are simply, factually incorrect. Others, while not blatantly wrong, are difficult to reconcile with the facts.

One of the accepted truths of the Netflix narrative is that CEO Reed Hastings is obsessed with data and everything the company does is data driven (for example "What little Netflix has also shared about its programming strategy is that its every decision is guided by data."). The evidence in support of this belief is largely limited to a model that Netflix crowd sourced a few years ago and to endless assertions from executives at the company that they do know what they are doing despite evidence to the contrary.

Of course, all 21st century corporations are relatively data-driven. The fact that Netflix has large data sets on customer behavior does not set it apart, nor does the fact that it has occasionally made use of that data. Furthermore, we have extensive evidence that the company often makes less use of certain data then do most other competitors.

On pertinent case in point, particularly for the SEC, is churn rates.
But Netflix disagrees. “With respect to various operational metrics, management has evolved its use of these metrics as the business has evolved,” it wrote the SEC in response. Because it is so easy to quit and then restart a Netflix subscription, it said, “the churn metric is a less reliable measure of business performance, specifically consumer acceptance of the service.”
This is problematic on any number of levels. In terms of marketing, pricing and long-term corporate strategy, having a complete picture of how long people stay and why they leave is huge. The only excuse for not reporting churn would be if you had such a detailed picture of who was leaving and why that this additional metric was redundant.

In other words, Hasting should have a good, data-supported explanation for a recent sudden loss of subscribers.
Netflix CEO Reed Hastings blamed the subscriber drop-off on a $1 price increase the company instituted back this spring.

"Our best sense is it's an effect of our price increase back in May," Hastings said Wednesday night in an interview with CNBC. "With a little bit higher prices, you get a little bit fewer subscribers. So that's our sense of it. But we can't be 100% sure. We had so much benefit from Orange in Q2 and the early Q3, but that's what we think."
Phrases you don't want to hear in these circumstances include "our best sense" and "that's what we think." They convey the impression of a CEO who was blindsided by a bad day at the NASDAQ.


When contemplating a price increase, well-run companies look at the impact on retention and on acquisition. When Netflix management said
[M]anagement believes that in a largely fixed-cost streaming world with ease of cancellation and subsequent rejoin, net additions provides the most meaningful insight into our business performance and consumer acceptance of our service. The churn metric is a less relevant and reliable measure of business performance, and does not accurately reflect consumer acceptance of our service.
They were basically saying that losing one customer and gaining another is the same as keeping the same customer. That's a dangerous approach under the best of circumstances but it can be deadly when trying to gauge the impact of a pricing change.

Just to be clear, for years analysts and the SEC have been asking for more data, or at least more detailed statistics and Netflix has been saying "trust us, the aggregate number are good enough." Now the company appears to have screwed up badly, and they've done it in pretty much exactly the way you would expect a company to screw up when it doesn't drill down into the data.

Sunday, July 21, 2019

More Apollo reblogging

Monday, June 11, 2018

An alternate narrative of JFK's commitment to the moon




[I would love some pushback on this. The following goes very much against the conventional narrative which always makes me nervous. If I missed something obvious, I'd rather it gets pointed out here before I build on it.]

The standard story centers on how the nation's imagination was captured by an audacious dream of sending a man to the moon. You've all heard the words of the speech that inspired the country, “We choose to go to the moon...” Except it didn't. The speech was an attempt at drumming up support for a not-that-popular program. As best I can tell, it was a fairly minor and underwhelming effort. It only achieved greatness retroactively due to the tragedy and triumph that came afterwards.

What else does the standard narrative get wrong?

1. Despite everything you hear about the tensions between JFK and LBJ, Kennedy knowingly committed his administration to what was probably Johnson's most cherished policy objective going back to his days in the Senate. Kennedy even put Johnson in charge of National Aeronautics and Space Council. Increasing the budget for manned space exploration was deeply controversial with in the administration. Kennedy's own science advisor, Jerome Wiesner was strongly opposed to it. One of Kennedy's last acts as president was dismissing Wiesner.

2. Of course, administrations failed to deliver on commitments all the time. It could very easily have been pushed aside and things turned out differently.

3. Is also worth noting that while we now see this as a bold objective, the goal did not seem as wildly ambitious at the time. [This is where I veer sharply from the conventional narrative, so this would be a good place to focus your objections.] It is essential to remember where the country's attitudes and expectations toward technology and progress were in the early sixties. As I have said probably too many times, like the late 19th/early 20th centuries, the postwar era was a period of explosive ubiquitous change. As with the turn of the century, there was a sense of constant acceleration. Everything seemingly came faster and easier than the experts predicted. Kennedy was being ambitious, but probably not as ambitious as we tend to remember him being.

4. While modern commentators choose to emphasize soaring rhetoric and the importance of visionary leaders, the overwhelming driver of the space race was the Cold War. There were very real and disturbing consequences to losing this race, both strategic and symbolic. What's more, there was a strong symbiotic relationship between the military and programs like Mercury and Apollo.


5. The Apollo program proved to be far more expensive than expected and quite controversial. Even with the impetus of the Cold War, the decision not just to see it through, but to make the deadline owes a great deal to a series of events breaking in its favor, particularly the assassination and the '64 landslide. Both the legend of JFK and the political power of LBJ meant that Apollo would get what it needed.


Today the very term “moonshot” has become one of the most reliable red flags for bullshit in the 21s century. We tell ourselves lies about what happened than hold up a fabricated past to justify the lies we tell ourselves about the present.

Saturday, July 20, 2019

Repost: Some context for the Apollo Anniversary

Thursday, November 8, 2018

A few points on Willy Ley and "the Conquest of Space"

To understand the 21st century narrative around technology and progress, you need to go back to two eras of extraordinary advances, the late 19th/early 20th centuries and the postwar era. Virtually all of the frameworks, assumptions, imagery, language, and iconography we use to discuss and think about the future can be traced back to these two periods.

The essential popularizer of science in the latter era was Willy Ley. In terms of influence and popularity, it is difficult to think of a comparable figure. Carl Sagan and Neil Degrasse Tyson hold somewhat analogous positions, but neither can claim anywhere near the impact. When you add in Ley's close association with Werner von Braun, it is entirely reasonable to use his books as indicators of what serious people in the field of aerospace were thinking at the time. The excerpt below comes with a 1949 copyright and gives us an excellent idea of what seemed feasible 70 years ago.

There is a lot to digest here, but I want to highlight two points in particular.

First is the widespread assumption at the time that atomic energy would play a comparable role in the remainder of the 20th century to that of hydrocarbons in the previous century and a half, certainly for power generation and large-scale transportation. Keep in mind that it took a mere decade to go from Hiroshima to the launch of the Nautilus and there was serious research (including limited prototypes) into nuclear powered aircraft. Even if fusion reactors remained out of reach, a world where all large vehicles were powered by the atom seemed, if anything, likely.

Second, check out Ley's description of the less sophisticated, non-atomic option and compare it to the actual approach taken by the Apollo program 20 years later.

I think we have reversed the symbolic meaning of a Manhattan project and a moonshot. The former has come to mean a large, focus, and dedicated commitment to rapidly addressing a challenging but solvable problem. The second has come to mean trying to do something so fantastic it seems impossible. The reality was largely the opposite. Building an atomic bomb was an incredible goal that required significant advances in our understanding of the underlying scientific principles. Getting to the moon was mainly a question of committing ourselves to spending a nontrivial chunk of our GDP on an undertaking that was hugely ambitious in terms of scale but which relied on technology that was already well-established by the beginning of the Sixties.

________________________________________________

The conquest of space by Willy Ley 1949
Page 48.

In general, however, the moon messenger [and unmanned test rocket designed to crash land on the moon – – MP] is close enough to present technological accomplishments so that its design and construction are possible without any major inventions. Its realization is essentially a question of hard work and money.

The manned moonship is a different story. The performance expected of it is, naturally, that it take off from the earth, go to the moon, land, takeoff from the moon, and return to earth. And that, considering known chemical fuels and customary design and construction methods, is beyond our present ability. But while the moon ship can make a round-trip is unattainable with chemical fuels, a moon ship which can land on the moon with a fuel supply insufficient for the return is a remote possibility. The point here is that one more attention of the step principle is possible three ships which landed might have enough fuel left among them for one to make the return trip.

This, of course, involves great risk, since the failure of one ship would doom them all. Probably the manned moon ship will have to be postponed until there is an orbital nation. Take off from the station, instead of from the ground, would require only an additional 2 mi./s, so that the total works out to about 7 mi./s, instead of the 12 mi./s mentioned on page 44.

Then, of course, there is the possibility of using atomic energy. If some 15 years ago, a skeptical audience had been polled as to which of the two "impossibilities" – – moon ship and large scale controlled-release of atomic energy – – they considered less fantastic, the poll would probably have been 100% in favor of the moon ship. As history turned out, atomic energy came first, and it is now permissible to speculate whether the one may not be the key to the other.

So far, unfortunately, we only know that elements like uranium, plutonium, etc., contain enough energy for the job. We also know that this energy is not completely accessible, that it can be released. He can't even be released in two ways, either fast in the form of a superexplosion, or slowly in a so-called "pile" where the energy appears mainly as he. But we don't know how to apply these phenomena to rocket propulsion. Obviously the fissionable matter should not form the exhaust; there should be an additional reactant, a substance which is thrown out: plain water, perhaps, which would appear as skiing, possibly even split up into its component atoms of hydrogen and oxygen, or perhaps peroxide.

The "how" is still to be discovered, but it will probably be based on the principle of using eight fissionable element's energy for the ejection of a relatively inert reactant. It may be that, when that problem has been solved, we will find a parallel to the problem of pumps in an ordinary liquid fuel rocket. When liquid fuel rockets were still small – – that was only about 17 years ago and I remember the vividly – – the fuels were forced into the rocket motor by pressurizing the whole fuel tank. But everybody knew then that this would not do for all time to come. The tank that had to stand the feeding pressure had to have strong walls. Consequently it was heavy. Consequently the mass ratio could not be I. The idea then was that the tank be only strong enough to hold the fuels, in the matter of the gasoline tank of a car or truck or an airplane, and that the feeding pressure should be furnished by a pop. Of course the pump had to weigh less than the saving in tank wall weight which they brought about. Obviously there was a minimum size and weight for a good home, and if that minimum weight was rather large, a rocket with pumps would have to be a big rocket.

It happened just that way. Efficient pumps were large and heavy and the rocket with pumps was the 46 foot the two. The "atomic motor" for rockets may also turn out to be large, the smallest really reliable and efficient model may be a compact little 7 ton unit. This would make for a large rocket – – but the size of a vehicle is no obstacle if you have the power to move it. Whatever the exhaust velocity, it will be high – – an expectation of 5 mi./s may be conservative. With such an exhaust velocity the mass ratio of the moon ship would be 11:1; with an exhaust velocity of 10 mi./s the mass ratio would drop .3:1!

The moon ship shown in the paintings of the second illustration section is based on the assumption of a mass ratio of this order of magnitude, which in turn is based on the assumption of an atomic rocket motor.

Naturally there would be some trouble with radioactivity in an atomic propelled rocket. But that is not quite as hard to handle as the radioactivity which would accompany atomic energy propulsion under different circumstances. A seagoing vessel propelled by time and energy could probably be built right now. It would operate by means of an atomic pile running at the center high enough to burden and water steam. The steam would drive a turbine, which would be coupled to the ships propeller. While all this mechanism would be reasonably small and light as ship engines go, it would have to be encased in many tons of concrete to shield the ships company against the radiation that would escape from the pile and from the water and the skiing the coolant. For a spaceship, no all-around shielding needed, only a single layer, separating the pilot's or crew's cabin in the nose from the rest of the ship. On the ground a ship which had grown "hot" through service would be placed inside a shielding structure, something like a massive concrete walls, open at the top. That would provide complete shielding or the public, but a shielding that the ship would not have to carry.
The problem that may be more difficult to handle is that of the radioactivity of the exhaust. A mood ship taking off with Lee behind a radioactive patch, caused by the ground/. Most likely that radioactivity would not last very long, but it would be a temporary danger spot. Obviously moon ship for some time to come will begin their journeys from desolate places. Of course they might take off by means of booster units producing nothing more dangerous in their exhaust them water vapor, carbon dioxide, and maybe a sulfurous smell.