Apr 032015
 

Every now and then you stumble across something that provides tantalizing yet nonchalant hints to something amazing. Recently this occurred while perusing a Boeing report on closed life support systems for spacecraft. One concept mentioned and minimally described was a previous 1981 study of a spacecraft meant to transport crew to the asteroid belt for the purpose of mining asteroids for their resources. Just the basic concept was fairly amazing on its own, especially all the way back in 1981. Second: the propulsion system was vaguely described as a nuclear fusion system. Third: well, here’s the disappointingly small diagram that was included for illustration purposes. See if you can see what makes the design especially interesting…

boeing 81 asteroid transport

What can be seen: three arms that rotate for artificial gravity; three vast radiator fins and a relatively tiny fusion engine in the tail. But what makes the design amazing: just in front of the spacecraft is a Space Shuttle Orbiter, giving a sense of scale to the vehicle. It’s *vast.* And it would have to be… the cargo transported to the asteroid was 150 metric tons. Plus the passengers, all 1,250 of them. All ONE THOUSAND TWO HUNDRED AND FIFTY of them.

The vehicle massed 10,000 tons; the powerplant (two 6 GW fusion reactors, spitting out 4.8 GW of thrust power, 2.8 GW of heat needing radiating and 4.4 GW of high energy neutron) massed 2000 tons; 4000 tons of hydrogen fuel; and 4000 tons of spacecraft/payload/passengers. The vehicle would boost for 11 days, coast for 226 days and brake for 13 days to rendezvous.

That, sadly, is all that’s available in the report I have. A FOIA request has been made for the reference that *seems* like might describe this further.

I hope to be able to define this vehicle further. As it is I can only guesstimate sizes; the habitation modules at the ends of the arms appear to be repurposed Shuttle External Tanks. But even nine of them would seem to be kinda cramped for 1250 people for two-thirds of a year… nearly 140 passengers per tank.

 Posted by at 11:11 am
Apr 022015
 

Another piece of artwork depicting the construction of a solar power satellite. This design features a “trough” design. Instead of a vast flat plain covered in PV arrays, this design had a central strip of PV cells between two walls of very reflective and very lightweight mylar (or a similar reflective foil). Thus the same total amount of sunlight would be directed to PV cells. Since PV clls generally work slightly better at higher illumination levels, in theory this type of PV array should generate more power for the same frontal area.

Shown slightly to the right of center is the aimable microwave emitter used to beam the energy to a receiving station on Earth.

rockwell 77 sps

 Posted by at 10:20 pm
Mar 282015
 

I’ve had a stack of fiche and a number of rolls of microfilms sitting around doing nothing for a decade and more due to a lack of ability to get good images off ’em. Every scanner I came across out in the wild would only do two-bit black-and-white scans, which turned the already dubious image quality into useless mush; efforts to capture the images via photography were roughly equally useless. Fortunately, at long last, I found that the University library up in Logan has microform scanners that do proper grayscale. So today I blew a number of hours digging through some old periodicals (“Space World”) and making scans. At last I can get half-ass decent copies of a whole bunch of German V-2 diagrams, among other things.

a-4 071nuke 232 focke wulf 013 saturn test 1 saturn test 3

The image quality still kinda blows compared to good scans taken directly off the documents, but this is about as good as it’ll get for microfiche.

 

 Posted by at 10:40 pm
Mar 282015
 

OK, right up front: What Freeman Dyson meant when he first described the concept now called a “Dyson Sphere” was that a civilization sufficiently advanced would build so many space habitats and solar power satellites that the cloud of ’em would blot out the star they orbit. Since the artificial structures would re-radiate the sunlight they receive as lower-energy infra-red (basic physics: if you want to maintain a stable temperature, total energy coming into the system needs to precisely balance total energy leaving), from the outside the Dyson sphere would appear dark… but in infra-red it’d be a great big glowing thing.

The idea of the vast cloud was quickly interpreted as a giant solid “bubble” around the star. This vast construct would absorb all of the suns output, and would result in a monumentally vast place to live. If the star was much like the sun, the Dyson Sphere would need to be at least one AU in radius to keep the temperature roughly Earthlike. But there are of course problems: primary of which is that no material known to science, theorized by science or even guessed at could withstand the stresses involved. Additionally, there’s the problem of gravity. There would be none on the inside of the shell, except for that produced by the star; if you stood on the inside of the shell, you’d fall “up” into the sun. If you stood on the outside of the shell, you’d still have the suns gravity pullign you down… but at 1 AU from the star, that gravity would be miniscule. The gravity added by the sphere itself would be vastly more miniscule, given that its mass would be a tiny fraction of the mass of the star. So to live in or under a Dyson sphere with a Sol-type sun, you’d need artificial gravity habitats, either rotating structures or whatever magical “gravity generators” you can scrape up.

But a new type of Dyson sphere has just been described by two fellers from the Department of Physics of Bogazici University, Bebek, Istanbul, Turkey. Instead of building the shell around a Sun-like star… build it around a white dwarf. The resulting shell will be far smaller if it is to be at the “habitable zone,” since white dwarfs are far less luminous than main sequence stars. But a side benefit here is that the reduced Dyson sphere radius (depending on the white dwarf… from about 2,000,000 km to a bit over 4,000,000 k) results in surface gravities right near Earth normal. So humans would be able to comfortably live on the surface, using energy intercepted within the sphere to provide illumination.

The down side is that the problems of physical stresses within the Dyson sphere, already bad with the 1-AU-type sphere, become much worse at the smaller radius and higher gravity loading. But presumably by the time humans are ready to tear planets apart to build shells around distant stars, we’ll have made important advances in the field of materials science.

Download the PDF file of the paper here:

Dyson Spheres around White Dwarfs

 Posted by at 9:01 pm
Mar 272015
 

I have made some adjustments to the Aerospace Projects Review Patreon campaign. The first is that I’ve reduced the number of rewards levels, which I was informed was previously Too Many. More importantly, I have added some new rewards: if you become a patron at $5 or more per month, you receive 10% off all future purchases of APR, US Aerospace Projects and downloadable Documents and Drawings. If you become a patron at $10 per month, you will receive 20% off any such purchases. Check of the APR Patreon here: https://www.patreon.com/user?u=197906

Additionally, the campaign has reached the point where the rewards are now *three* aerospace documents, one high-rez historical diagram and one all-new CAD diagram per month. This is in addition to the random “Extras” I throw in for $4 and up patrons. The most recent extra is a full-rez restoration of a three-view diagram of a 1978 McDonnell-Douglas concept for modifying Skylab to be serviced by the Space Shuttle. You can see a smaller-rez version of that here: http://www.aerospaceprojectsreview.com/blog/?p=2153

If you sign up now you will get the latest rewards which include:

  • A Bell Aircraft presentation on the SR-126 Bomber Missile, a manned ICBM predecessor of the Dyna Soar
  • A Lockheed paper on the history of the Polaris to Trident Fleet Ballistic Missile
  • A large poster illustrating the missiles and rockets of the Orbital Sciences Corporation
  • An all-new CAD diagram detailing the 10-meter Orion nuclear pulse propulsion vehicle designed by General Atomic for the USAF
 Posted by at 7:39 pm
Mar 262015
 

Before Skylab fell out of the sky, a lot of people wondered “why doesn’t NASA just send a Space Shuttle to rendezvous with it and use it as a space station.” In the end, Skylabs orbit decayed earlier than expected due to solar activity heating up the outer atmosphere, increasing drag on the station. Coupled with delays in getting the Shuttle up and running, time simply ran out.

But for a while, the idea of rescuing Skylab and making use of it in orbit made sense. McDonnell-Douglas, for example, turned in a proposal for modifying Skylab with a substantial upgrade in power by way of very large photovoltaic “wings.” This proposal was dated December, 1978, far too close to the July 1979 destruction of Skylab for the idea to have had any hope of implementation.

The McDonnell-Douglas plan would have added additional thermal shielding to the main workshop and a Spacelab module for additional volume. New thermal radiators and docking facilities for the Shuttle would also have been added.

Shuttle + skylab diagram small

The full-rez version of this diagram has been made available to APR Patreon patrons at the $4 level.

 Posted by at 4:17 pm
Mar 242015
 

An artists rendering of a solar power satellite under construction. This idea was popular for a while in the mid/late 1970s during the energy crisis, and generally called for satellites generally compared in size to Manhattan island.

This image was apparently created by NASA in 1976.  The thinking at the time was that these structures could certainly be built within the 1990’s; I often wonder at what the people who were working on them would have thought at the time had they somehow found out that, nearly 40 years later, precisely zero effort would have been made to see SPS come to pass. A higher-rez version is available HERE.

sps construction

 Posted by at 12:34 am
Mar 212015
 

Eugen Sanger was an Austrian engineer from the early/mid 20th century. While largely forgotten by the vast majority of everybody today, he is remembered, at least in aerospace circles, as the originator of the Silbervogel (“Silverbird”) rocket-powered suborbital bomber. This work was performed during WWII for the German government, and included some substantial rocket testing; the odd thing – though wholly in character for the Nazi regime – was that this work was entirely separate from the development work  on the V-2 rocket. Had the efforts been brought together, chances are that German rocketry would have been further advanced by the end of the war.

In 1934, Sanger published  a paper on advancement in liquid propellant rocketry, work that would later feed into his Silverbird effort. “Recent Results in Rocket Flight Technique” not only reported upon work done in developing a gas-oil and liquid oxygen burning rocket engine, but also proposals for manned rocket powered aircraft. The paper was originally written in German and granted the catchy title “Neuer Ergebnisse der Raketenflugtechnik,” but it was translated into English by the National Advisory Committee for Aeronautics in April of 1942. Why was it was translated just then? Depending on the speed of the translators, the work may have begun just after the American entry into WWII, which might indicate a bit more interest in German rocketry in certain portions of the US Government than has generally been understood.

The abstract & such for the report can be seen on the NASA Technical Report Server HERE. Or it can be directly downloaded as a 33 meg PDF HERE.

Note: my original plan for this writeup was to include verbiage along the lines of “Sorry that the two-bit black-and-white scan quality is so poor, but whatcha gonna do.” But in looking it up, I found that the original bleah-quality scan has been replaced with a higher quality full-color scan. This is a good thing!

sanger1 sanger2 sanger3

 

Much more aerospace stuff is available via the APR Patreon.

patreon-200

 Posted by at 7:46 pm
Mar 152015
 

Another ebay auction presents a display model of a transport version of the McD Model 260 VTOL from the 1970’s:

s-l1600a s-l1600b s-l1600c s-l1600d s-l1600e s-l1600f s-l1600g s-l1600h s-l1600i s-l1600j

A great many Model 260 variants were designed, all based on the same basic concept: an aircraft shaped much like a corporate jet, featuring a pair of turbofan engines of very high bypass ratio located in shrouds which could unfold to direct the thrust downward for vertical lift and hover. Unlike the Rockwell XFV-12, the Model 260 could probably have worked, but it was never built.

 Posted by at 2:57 pm