Skyhook 2

[Gene Cryder]

Askyhook is a proposed momentum exchange tether that aims to reduce the cost of placing payloads into low Earth orbit. A heavy orbiting station is connected to a cable which extends down towards the upper atmosphere. Payloads, which are much lighter than the station, are hooked to the end of the cable as it passes, and are then flung into orbit by rotation of the cable around the center of mass. The station can then be reboosted to its original altitude by electromagnetic propulsion, rocket propulsion, or by deorbiting another object with the same kinetic energy as transferred to the payload.

A skyhook differs from a geostationary orbit space elevator in that a skyhook would be much shorter and would not come in contact with the surface of the Earth. A skyhook would require a suborbital launch vehicle to reach its lower end, while a space elevator would not.

Different synchronous non-rotating orbiting skyhook concepts and versions have been proposed, starting with Isaacs in 1966,[1][2] Artsutanov in 1967,[3][4] Pearson[5] and Colombo in 1975,[6] Kalaghan in 1978,[7] and Braginski in 1985.[8] The versions with the best potential involve a much shorter tether in low Earth orbit, which rotates in its orbital plane and whose ends brush the upper Earth atmosphere, with the rotational motion cancelling the orbital motion at ground level. These "rotating" skyhook versions were proposed by Moravec in 1976,[9][10] and Sarmont in 1994.[11][12]

This resulted in a Shuttle-based tether system: the TSS-1R mission, launched 22 February 1996 on STS-75 that focused in characterizing basic space tether behavior and space plasma physics.[13] The Italian satellite was deployed to a distance of 19.7 km (12.2 mi) from the Space Shuttle.[13]

In 2000 and 2001, Boeing Phantom Works, with a grant from NASA Institute for Advanced Concepts, performed a detailed study of the engineering and commercial feasibility of various skyhook designs. They studied in detail a specific variant of this concept, called "Hypersonic Airplane Space Tether Orbital Launch System" or HASTOL. This design called for a hypersonic ramjet or scramjet aircraft to intercept a rotating hook while flying at Mach 10.[14]

By rotating the tether around the orbiting center of mass in a direction opposite to the orbital motion, the speed of the hook relative to the ground can be reduced. This reduces the required strength of the tether, and makes coupling easier.

The primary message we want to leave with the Reader is: "We don't need magic materials like 'Buckminster-Fuller-carbon-nanotubes' to make the space tether facility for a HASTOL system. Existing materials will do."[14]

The capture-ejector rim is a variation that consists of a rim- or ring-shaped structure. Like a rotating skyhook, it would rotate in a direction opposite to its orbital motion, allowing a spacecraft at suborbital velocity to attach to its lower portion and later be flung into orbit from its upper portion. It would be easier for a spacecraft to attach to the lower portion of a capture-ejector rim than to attach to the end of a skyhook (which would only point downwards for a brief period of time).[17]

Skyhook is a toolkit for building complex drag and drop interfaces inAngular. It is based on, and very similar to react-dnd by DanAbramov and others, and is also powered by dnd-core. Itis compatible with all backends.

High performance. All code runs outside the Angular zone, andre-enters in batches only where strictly necessary, such that change detectionruns precisely as many times as you need it to, with no extra configuration.You should also be able to take full advantage of OnPush change detection.

Instead of building maximally-ergonomic solutions to simple use cases,react-dnd and @angular-skyhook provide an abstraction over most things youcould want to do with drag and drop. They are lower-level building blocks thatmake it easy to implement some very complex interactions. They assign nospecific meaning to a drag/drop operation. You get to define what happens whena drag starts or ends or hovers. Here are some ambitious examples:

It is important to note that for bare-bones sortable lists, where you havea mutable array of simple values, you don't necessarily need the superpowers inthis library. There are plenty of cookie-cutter solutions out there, like thequite powerful ng2-dnd or ng2-dragula, which mayget you to your deadline faster than learning and using @angular-skyhook. Butbe warned; you may find yourself wanting more dragging power once you geta taste. In fact, this package was born when@cormacrelf got sick of maintainingng2-dragula and watching users struggle to implement what react-dnd was bornfor.

Not all issues are @angular-skyhook-related. If you think you found a bug indnd-core or with the HTML5 backend, those issues belong on thatcodebase with their many contributorsand wealth of experience. If there is a problem with another backend you areusing, file an issue with that backend so you can get more specific help and sothat the community can benefit.

For assembly, material handling and welding applications, ALM Positioner's elevating 3-Axis Skyhook & Drop Center Positioners are capable of 3 axes of motion, creating an efficient and cost-effective workplace.

With a relatively small footprint, the skyhook positioner is ideally suited for material handling abilities in confined spaces. Drop Center Positioners offer 3 axes of positioning in weight capacities 12,000 lbs. and higher. Rated load capacities are based on the center of gravity (CG) locations of the part/tool.

You could probably cobble together a skyhook using KAS's winch and a balloon mod (Procedural Airships, Professor Phineas Kerbenstein's wonderous vertical propulsion emporium, Hooligan Labs). Use girders for the actual catching mechanism since they have a high impact tolerance.

After reading the wiki, the Skyhook plane was going about 55 m/s, so you're not actually going to save a lot of delta-V versus landing - just 55 m/s at best. At worst, you'll spend more than that staying aloft while trying to hit the hook exactly. You don't save any delta-V on the ascent since you still have to accelerate all the mass of the plane and the pickup package up to orbital velocity.

alright. i guess your right, it does seem a bit impractical. although, really, most project (by me atleast) dont have a really good reason why to even bother with it in the first place. maybe there would be some obscure use, but nothing a helicopter with KAS winch cant do.

The poster hung above my bedroom dresser, a painting lifelike in its details but abstract in concept, the head and shoulders of Kareem Abdul-Jabbar leaning to the left as he tossed a hook shot against a backdrop of a cloud-spotted sky.

In retrospect, my wall was covered with athletes doing what defined them. Magic Johnson smiling; James Worthy soaring for a dunk, the ball held straight above his head like the Statue of Liberty's torch; Michael Jordan in the original Air Jordan poster, captured mid-flight, his arms and legs spread wide in a pose that became the logo worn on millions of high-tops. Kareem with his skyhook.

It can be an article of clothing, such as Abraham Lincoln's stovepipe hat or Tiger Woods' red Sunday shirts. It can be a familiar instrument like B.B. King's guitar, Lucille. It can be as simple as a single word: Marv Albert's "Yes!"

In order to make something so simple seem so distinctive it has to be done over and over again, through solitary repetition and on stage when everyone's watching. I've seen that rhythmic skyhook so many times it's burned in my head like an image left on a computer screen too long. His left leg is straight, the right knee comes up, the left arm extends out, the right arm rises up with the ball and finally the wrist flicks to add the backspin, the seams rotating as the ball arcs to the hoop and drops through the net.

It's not that Abdul-Jabbar created the skyhook. But sometimes it's better to perfect things than do them first. Liza Minnelli had the first crack at "New York, New York," but Frank Sinatra's version is the one you mostly hear played at Yankees and Knicks games. In basketball, where talent eventually overrides everything else, victory belongs to the appropriators more than the innovators.

You probably never heard of Dean Berry. He was a reserve guard for the Georgetown Hoyas who played only 50 minutes in the 1995-96 season. But in practices he taught Allen Iverson the crossover dribble move that Iverson used so effectively in the NBA.

We can thank George Mikan and Cliff Hagan for the origins of Abdul-Jabbar's hook shot. Abdul-Jabbar doesn't have memories of watching Mikan, the Minneapolis Laker who was the NBA's first dominant big man. But he did use the drill that was named for him and consisted of shooting a hook shot from the right side with the right hand, then a hook from the left side with the left hand and repeating while slowly moving further away from the basket. Abdul-Jabbar did see Hagan use the hook shot as a player for the St. Louis Hawks, a reminder that the hook could be used effectively at all levels of the game.

The greatest encouragement for Abdul-Jabbar to keep working on the hook was when he started playing in fifth grade and usually found himself going against kids who were older, just as tall and more physically developed than him.

As he practiced in the gyms and playgrounds of New York City, he extended his shooting range. The NCAA banned the dunk when Abdul-Jabbar was at UCLA, so he used the hook to set scoring records and win 88 of his 90 collegiate varsity games.

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