Nazi “Sun Gun” references

AARRRGH, blather, Crazy, history, Hmm..., Meh., Patreon, projects, spacecraft, ಠ_ಠ 5 Responses »

Mar 202017

One of the oldest and most tiresome of the “Nazi Wunderwaffen” myths is that of the “Sun Gun.” The idea is that the Nazis were found to have been working on the design of an orbital mirror, miles in diameter, that would have reflected sunlight to the surface of Earth in such a way to cause enemy cities to burst into flames. This idea first hit the US press quite soon after the defeat of Nazi Germany, and *before* the nuking of Japan. Several articles appeared in the New York Times on the topic beginning in late June, 1945, and the idea reached its peak with an illustrated article in Life Magazine in July, 1945.

The “Sun Gun” was claimed to be a circular mirror one mile in diameter, orbiting at 5,100 miles. The mirror, it was claimed, would be made from large cubical and pressure-tight blocks, providing *vast* internal volume for the crew and their crop of oxygen-producing pumpkins.

Small problem: it’s BS.

Now, there *were* ideas for vast orbital mirrors. Hermann Oberth had proposed such a thing as far back as the 1920’s, so an orbital mirror was not unknown as a concept in wartime Germany. And in reading the lean details in the articles, it’s clear that what is described is the Oberth mirror as described after a round of “telephone.” The basic idea is Oberths, and Oberth even gets a shout-out in the articles, but Oberths ideas got mutated and bent out of recognition. Not leastways because an orbital mirror a mile in diameter 5,100 miles overhead *cannot* set a city, or even a dry piece of of tissue paper on fire. The basic physics of optics prohibits that. Thought experiment: take a mirror one inch in diameter. Can you use it to start a fire? If it’s precise enough and close enough to the target… sure. Now, move that one-inch mirror 5,100 inches from the target. Gonna set anything on fire *now?*

I suspect what happened is that the the US Army officers who reported on the “sun gun” were simply told about the Oberth mirror – which, by the way, was a far less insane idea than the “sun gun” in that it was essentially foil rather than a large solid structure – by Germans who either wanted to screw with them or, like von Braun, wanted to pump up their apparent usefulness to the US military in the hopes of getting transferred to the US. Given the conditions in post-war Germany and the risks of getting sucked into the black hole of the Soviet Union, it would make sense for *anyone* to try to wrangle a ride to the US for an actual job.

I have gathered together scans of newspaper and magazine articles on the subject and mashed ’em into a PDF file which I have uploaded to the 2017-03 APR Extras Dropbox folder. This is available to all APR Patreon Patrons at the $4 level and above. If interested, check out the APR Patreon.

Trumps Proposed NASA Budget

Hmm..., news, science, spacecraft 9 Responses »

Mar 192017

Trump’s budget would cut NASA asteroid mission, earth science

On the plus side: “Earth science” is being cut. Now, I’m not opposed to “Earth science,” it’s simply not NASA’s gig. The NOAA would seem to be the proper place for that, just like funding for ISS should come not from the NASA budget but from the State Department. On the downside, the asteroid capture mission seemed to me like one of the few useful missions for Orion/SLS.

A more involved discussion of what’s cut is HERE. Also cut is the Europa lander and NASA’s education program.

NASA’s overall budget is proposed to be cut 0.8% over the previous years. This is small compared to other proposed budget cuts across the federal budget… but it’s *YUUUGE* compared to the cuts that are happening in the entitlement programs. And that’s sad, given that entitlements are the areas that are sucking up the biggest chunk of the government and only getting bigger.

Here’s a thought: for a ten-year period, let’s flip the Medicare and NASA budgets, and then see how things stand.

A modicum of fear-mongering to brighten your weekend

awesomeness, blather, Hmm..., news, Nuclear Pulse Propulsion, nukes, projects, science, science fiction, spacecraft, weapons 2 Responses »

Mar 192017

Mini-nukes and mosquito-like robot weapons being primed for future warfare

Most of the article deal with the threat of nanotechnological weapons. I’m personally not terribly concerned about them… in theory they’re nightmares, but in practicality the chances of a mechanism the size of a bacteria functioning for very long in the wild is low. “Nano-scale” metal is extremely fine dust… dust that will oxidize almost instantly in an oxygen environment. Dust that has such a vast surface area to volume ratio that thermal control would be virtually impossible.

I suspect it’d be possible to design nanites that will function in specific environments. But The “gray goo” threat seems to me unlikely.

The headline contains a reference to something else that interests me more than nanites: “mini nukes.” But here again, the description seems more sci-fi than practical:

Nanotechnology opens up the possibility to manufacture mini-nuke components so small that they are difficult to screen and detect. Furthermore, the weapon (capable of an explosion equivalent to about 100 tons of TNT) could be compact enough to fit into a pocket or purse and weigh about 5 pounds and destroy large buildings or be combined to do greater damage to an area.

“When we talk about making conventional nuclear weapons, they are difficult to make,” he said. “Making a mini-nuke would be difficult but in some respects not as difficult as a full-blown nuclear weapon.”

Del Monte explained that the mini-nuke weapon is activated when the nanoscale laser triggers a small thermonuclear fusion bomb using a tritium-deuterium fuel. Their size makes them difficult to screen, detect and also there’s “essentially no fallout” associated with them.

The description seems to be a miniaturized version of an inertial confinement fusion system… lasers causing a pellet of fusion fuel to implode. So far in order to get a pellet the size of a grain of sand to fuse has required a laser system the size of a warehouse; compressing all that down to the size of a briefcase seems… optimistic.

Still, *IF* that compression becomes possible, then these mini-nukes need to be put into production *now.* Not just for the military potential… but more importantly because they would finally make Orion propulsion clean and reasonably cheap.

What causes fear among the author and subjects of this article would cause great joy among people able to envision a wider view.

Space Shuttle: Developing an Icon 1972-2013

awesomeness, books, history, projects, rockets, spacecraft 5 Responses »

Mar 102017

So here I was, minding my own business when several of my cats started acting glitchy. This is not unknown… where some dogs will bark their damnfool heads off if they hear a stranger on their turf, my cats warn me of visitors or trespassers in their own quieter way. In this case it was a UPS truck and the driver bringing a box to my door. As I hadn’t ordered anything recently, this was a puzzlement.

As it turns out, it was a copy of Dennis Jenkins three-volume book “Space Shuttle: Developing an Icon 1972-2013.” This is the latest, and presumably last, edition of the premiere tome on the history of the Space Shuttle. It is vastly expanded from the previous editions, now over 1,500 pages.

In short… if’n you’re at all interested in the Space Shuttle, procure yourself a copy of this book. It’s a billet of hardback paper massive enough to brain an ape, filled with full-color art & photos, diagrams and data galore. The first volume describes the early history of the Shuttle from World War II up through the 70’s; the second volume is a detailed technical description of the Space Transportation System. The third volume describes the operational history of the Shuttle program.

If you like projects/unbuilt designs, the first volume in particular provides an embarrassment of riches.

In short, I wholeheartedly endorse this book. It’s friggen’ awesome.

With every purchase of “Space Shuttle,” you’ll receive one free Raedthinn-approved Fort Of Imagination.

Note: seems my copy came to me due to my having contributed very, very slightly to it, another concept I wholeheartedly approve of. Thus, thanks to Dennis Jenkins for providing me with this!

Pan is a funky moon

awesomeness, Hmm..., news, photography, science, spacecraft 5 Responses »

Mar 092017

Now that the Cassini space probe is doing death-defying dives past the Saturnian ring system, it’s getting some close-up views of the dinky lil’ moon that inhabit the rings . One such moon (within the Enke gap) is Pan, which exhibits a very unusual feature… it’s own little ring system. In the case of Pan, the rings are accreted directly onto the surface, forming a pronounced equatorial ridge running all the way around the little (34.4×31.4×20.8 km) world. The rings are far thinner than most people understand… perhaps just a few meters. So unless the moon tumbles – and it appears that Pan does not – the moon will scoop up bits of dust on a single thin plane.

Pan is not alone… the moon Atlas shows the same structure.

NASA Software

Hmm..., science, spacecraft 2 Responses »

Mar 062017

As sort of a followup to this post from a few days ago, here’s a link. Like it says on the tin…

NASA Software

This is somewhat akin to the NASA Tech Report Server. Search for software, get results. However, the software falls into a range of categories, such as:

Open Source
U.S. Government Purpose Release
U.S. Release only
General Public Release
U.S and Foreign Release

A few you can “Download Now”, but from what I’ve seen with most you must “Request Now.”

Couldn’t find that warp core operating system I’ve been looking for. Must be behind the firewall.

Some aerospace art & photos for Patrons

aircraft, art, history, Patreon, projects, rockets, spacecraft 2 Responses »

Mar 042017

I have posted in the 2017-03 APR Extras Dropbox folder for APR Patrons a small pile of aerospace history images yoinked out of a few reports. Included is a 1944 NACA reconstruction of the German V-1 buzz bomb (generally correct, but off in detail), three photos of a wind tunnel model of the Bell X-1 modified to have variable sweep wings, three pieces of NASA art depicting some then-future applications of space propulsion systems including a one-man lunar flyer, an early concept for what became Skylab, and a more advanced modular space station. The full-rez verions are available to all APR Patreon patrons at the $4 level and above. If interested, please consider signing up. There are a whole bunch of other goodies available in past months folders, more stuff coming.

Much more aerospace stuff is available via the APR Patreon. If this sort of thing interests you, please consider signing up… not only will you help fund the search for obscure aerospace history, you’ll gain access to a lot of interesting stuff, not available elsewhere.

And so, the Democrat war on the Moon begins…

AARRRGH, dumbassery, Forward!, Gah., Hmm..., Meh., nukes, politics, rockets, science, science fiction, spacecraft, THIS is why Trump won, weapons, ಠ_ಠ 13 Responses »

Mar 012017

If you’ve been wondering how the party of fear-mongering and authoritarianism was going to respond to the idea of private American companies going to space and the moon, I believe we have us an early test balloon:

Congressional candidate: Moon-colonizing companies could destroy cities by dropping rocks

One “Brianna Wu” scientifically embarrasses herself, but likely improves her standing with the Luddites, by claiming that “Rocks dropped from there have power of 100s of nuclear bombs.”

Now, on one hand this is true. If you fling a big enough rock from the surface of the moon, it could hit the Earth with kinetic energy similar to the total energy of a nuke. But there’s the thing: in order to do that, you need to *impart* damn near a nukes worth of kinetic energy in the first place. Simply chucking a rock from the lunar surface at lunar escape velocity (about 2.4 km/sec) will not put that rock on a trajectory to the Earths surface, but rather just in a very wide orbit , basically the same orbit the moon has. You’d need to cancel out the orbital velocity, another kilometer or so per second. From there the rock would “fall” to Earth, picking up speed and smacking down with no more than Earth escape velocity, or no more than 11.2 km/sec. So, by accelerating a rock to about 3.5 km/sec, you get it to hit the Earth at about 11 km/sec.

Sounds great for a weapons system. At 11 km/sec, the kinetic energy of one kilogram of rock (or anything) is 60.5 megajoules. One single kiloton of yield is defined as 4.184 terajoules. So to get a kiloton of bang out of a lunar rock, you’d need to launch (4.184 terajoules/60.5 megajoules) 69,157 kilos of rock. Lobbing a seventy-metric ton rock to 3.5 kilometers per second is a non-trivial act. Plus, you have to assure that the rock not only hits the target via accurate guidance, but survives passage through the atmosphere.

But Wu didn’t just say that a rock would have the power of a nuke, but “hundreds” of them. So… let’s say 100 times Fat Man, or 1.5 megatons. That would require the launch not of 70 metric tones, but 105,000 metric tons. The USS Nimitz displaces about 100,000 metric tons. So according to Ms. Wu, the threat posed by the likes of Elon Musk is that he will toss aircraft carriers off the surface of the moon.

Ms. Wu then went on to claim that any criticism of her rather unrealistic fearmongering was due to sexism, and to then decry the militarization of space. Because apparently a few tourists going around the moon will be able to grab chunks of moonrock the size of a carrier battle group and hurl it at Earth.

Silly as her fears are, I won;t be the least bit surprised if they gain traction, and this is used as the basis of an attempt to shut down private spaceflight in the US… or at least to nationalize it “for the children.”

Thanks to blog reader SE Jones for heads-up on this miserable little story.

As always, feel free to check my math.

And the Moon Race is on…

awesomeness, news, projects, rockets, spacecraft 35 Responses »

Feb 272017

Hmmm…

SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

We are excited to announce that SpaceX has been approached to fly two private citizens on a trip around the moon late next year. They have already paid a significant deposit to do a moon mission. Like the Apollo astronauts before them, these individuals will travel into space carrying the hopes and dreams of all humankind, driven by the universal human spirit of exploration. We expect to conduct health and fitness tests, as well as begin initial training later this year. Other flight teams have also expressed strong interest and we expect more to follow. Additional information will be released about the flight teams, contingent upon their approval and confirmation of the health and fitness test results.

If the Space Race comes back, and it turns out to be an ongoing race between Public and Private *American* programs…. why, that would make me… Hmmm. What’s the word I’m thinking of? It’s a word I don’t use often because I don;t have much use for it. Something like… hoppy? Harppy? Hooppy? Something like that.

However, let’s just say that I’m just a weee tad bit skeptical that SpaceX can go from “we’ve never launched a human nor a Falcon 9 Heavy” to “We used a Falcon 9 Heavy to send humans around the moon” in less that two years. But if they can… hmmm. Happers? Something…

Political Rocket Theater

history, Hmm..., news, rockets, spacecraft 40 Responses »

Feb 262017

Recently it was announced that the Trump administration has asked NASA to study the possibility of putting crew on the first SLS launch in 2019. If this comes to pass, it will entail sending an Orion capsule around the moon (and back, one would hope), the first time humans have left low Earth orbit in… well, a long-ass time.

What would be the scientific benefit compared the baseline plan of sending the capsule unmanned? Well… not a whole lot, especially given that the mission would be rather rushed. But the political benefits *could* be substantial. Assuming it’s a successful flight, it could be seen and sold as the return of America to having an actual space program (as opposed to the “hey, let’s go in circles a few times in an flying United Nations”). Two American astronauts will go back to the moon; not to land, of course, just to get within spitting distance of it. But almost certainly they will get there before any other nation could pull that off. One can of course argue that the US won the race to the moon in 1969, and anybody going there after all these years is a poor second… but in reality, the US has *long* since lost the direct experience and tribal knowledge that got Apollo tot he moon. Most of the people responsible for making Apollo work are dead or very, very retired. The US going back to the moon would be more like the US going for the first time, just again.

There are two obvious potential downsides to this:

Disaster. This could come in the obvious form of the crew being killed at any point during the mission. This could also come in the form of the changes in the mission causing so much trouble and delay and cost overruns that the entire launch gets scrapped. Remember, this flight, if it happens, will happen after the 2018 mid-terms. This flight will be Trumps’ baby, and, who knows, he could well be impeached by then.
How do you follow it up? It’s all well and good to fling some guys past the moon, but this could be done with a substantially smaller and cheaper system than SLS. A pair of Falcon 9 Heavies could certainly do it. The one thing that SLS brings to the party is massive lift capability, which in this case means the ability to send an actual lunar launder. But unless I missed a staff meeting… we have no lunar landers. We don’t even seem to have a real program to develop one.

SLS is meant to launch not only lunar missions but manned missions to Mars. Great! But there are no funded programs to develop actual Mars ships. Lots of people have lots of ideas for what SLS could launch. Some of the ideas are actually pretty good, such as very fast deep space probes, giant space telescopes, components for real space stations, etc. But none of them seem to have the most important feature any such idea needs to have: funding.

The first SLS flight, Exploration Mission 1 (EM-1) is already being assembled. So turning it into a manned flight would entail substantial modificationg to stuff already constructed… never an optimal solution. The second SLS flight, EM-2 scheduled for 2021, is intended to be manned and will have more advanced systems than will be available for EM-1. So it can be readily argued that making EM-1 manned is simply unwise. But the 2021 EM-2 flight would be after the inauguration of whoever wins the Presidential election of 2020. And does Trump – or anybody – really want President Warren to be in charge when NASA next tries to send men to the moon?

So here’s the calculation. NASA does this at Trumps behest, and it crashes and burns: this way leads to DOOOOOOM. NASA does this and succeeds: NASA is golden and Trumps scores points. Launch in 2019 and cement manned deep-space flight into NASAs schedule, or wait until 2021 when there’s a good chance that NASA will be controlled by an Administration that thinks that giant government spending programs are just awesome, so long as they don’t actually *build* anything.

Hmmm.

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