March 2018 – Aerospace Projects Review Blog

Hovertank and spaceplane

hi-rez, Patreon, spacecraft, spaceplane No Responses »

Mar 292018

Here are two presumably wholly unrelated pieces of aerospace artwork. At least I *hope* they’re unrelated…

The first is an anonymous painting of a spaceplane. Doesn’t seem terribly realistic; most likely done for advertising purposes (I wonder if the “7-11” might indicate a relationship to the chain of the same name). The print arrived damaged, as you an see; the paper was thick and *really* brittle and really didn’t appreciate being rolled up. If anyone knows anything about it, feel free to comment.

The second is concept art from Bell Aerospace illustrating an amphibious troop carrier for the Marine Corps. The design of the assault vehicle is fairly ordinary as such things go, except for one detail: it could turn into a hovercraft and float across the surface of the water, rather than plowing through it. No further details provided, so I don’t know if the hover-skirts were deployable and retractable, or if they were simply dropped when the vehicle got to shore. The latter would certainly seem more economical.

I’ve uploaded the full rez scans to the 2018-03 APR Extras Dropbox folder, available to all current APR Patrons at the $4 level and above. If you are interested in this and a great many other “extras” and monthly aerospace history rewards, please sign up for the APR Patreon. Chances are good that $4/month is far cheaper than your espresso/booze budget!

HL-20

rockets, space shuttle, space station, spacecraft, spaceplane No Responses »

Mar 292018

An old NASA video describing the HL-20 lifting body. In the 90’s NASA spent a lot of time and trouble trying to get an HL-20 built for a Personnel Launch System, a vehicle smaller than the Space Shuttle but capable of carrying as many passengers and riding a much smaller launch vehicle. For transporting passengers to and from the Space Station, it would have been much more economical and sensible than the Shuttle. And while the HL-20 was never built, the basic geometry has survived in the form of Sierra Nevada’s Dream Chaser, which *might* actually fly to space someday.

Solar Powered Spacecraft

rockets, spacecraft No Responses »

Mar 272018

A piece of late 1950’s promo art from Rocketdyne illustrating a spacecraft with a solar thermodynamic powerplant. This should not be assumed to be an actual design, but much more likely just more or less pure illustrative art.

The craft is shown with a great parabolic solar reflector, the sunlight heating an element at the focus. In an actual design, most likely a working fluid would be pumped through this and boiled, the resulting high pressure gas blowing past a turbogenerator and then into a heat exchanger or directly into a relatively vast radiator. The gas would be cooled back to liquid and recirculated. Note that no such radiator is in evidence. Sometimes early designs utilized radiators built onto the shadow side of the reflectors. The craft appears to be over Mars, based on the hints of canals that are kinda visible. The ship has a parabolic radio dish on a boom below; the upper boom would seem to hold a trough, likely a launching platform for a small probe rocket (another cliche in early spacecraft art). At the rear is a boom that appears to hold two banks of ion engines or some other electrical propulsion system. Oddly, the thrusters would seem to be held off well to the side of the craft, rather than actually firing through the centerline (unless that boom is supposed to be projected straight aft and mounted at one end of the bar holding the thrusters, thus putting the centerline of thrust back through the CG of the craft).

PDF Review: Wheelguns in Spaaaace

nukes, Patreon, PDF Review, spacecraft 3 Responses »

Mar 092018

Advanced “space guns,” typically lasers, railguns, coilguns, neutral particle beams and the like, have a problem: power. Nuclear reactors and solar panels can provide power for years at a time, but generally their steady-state power output is only a tiny fraction of the instantaneous power needed when the gun goes off. So to run a weapon that needs many gigawatts for a fraction of a second with a powerplant that produces kilowatts, you need an energy storage system that can convert that energy into power on a moments notice. Things like batteries are great in principle, but their weight is vast and their ability to release power at the high levels needed is generally poor.

Often this has resulted in space weapons that use chemical reactions to provide the power needed. This has meant that the total number of shots that can be fired is strictly limited.

In the 1980’s during the SDI heyday, Westinghouse looked at an alternate approach: rotating hoops. Giant wheels made of advanced composite materials would be spun up over time by a low-power system such as a nuclear reactor, and when needed these flywheels would be electromagnetically braked to generate vast amounts of power as the wheels ground to a halt. The system could be “reloaded” by slowly spinning the wheels up again… assuming the system hadn’t torn itself part.

The weapon shown below is probably largely notional, no masses or dimensions were given. But based on a smaller terrestrial unit (with ten hoops, each 14.5 meters diameter, massing 140,000 kg each, spinning at 1800 RPM to deliver a total of 1 gigawatt for 10 minutes to power anti-missile lasers and such), this can be assumed to be a fairly *vast* construction, far heavier than anything mankind has so far launched into orbit. Obviously such a thing would be impossible to launch as a unit; it would be assembled in space using spools of fibers wound in place. Presumably the weapon itself would be at least somewhat aimable independent of the flywheels… slewing *them* about to aim at a moving target would seem to be an exercise in futility.

This came from the paper “Rotating Hoop, Pulsed-Energy Converter” contained in “Transactions of the Fifth Symposium on Space Nuclear Power Systems.” A PDF of that can be downloaded if you go HERE and click the “PDF” button.

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