/sci/ - Science & Math

>>16245095
>Then you don't have to try and dock with a cable at hypersonic speeds
Its not the speed so much as the rather small time available to mate your cargo pod with the receiver on the skyhook tip

>>15722189
>>15722192
> build skyhooks for greater efficiency
based

>>15446685
>250 tonne payload
Don't let the nutjob mislead you about what technically informed people have concluded about skyhooks
>Phase I of Boeing's Hypersonic Airplane Space Tether Orbital Launch (HASTOL) study, published in 2000, proposed a 600 km-long tether, in an equatorial orbit at 610–700 km altitude, rotating with a tip speed of 3.5 km/s. This would give the tip a ground speed of 3.6 km/s (Mach 10), which would be matched by a hypersonic airplane carrying the payload module, with transfer at an altitude of 100 km. The tether would be made of existing commercially available materials: mostly Spectra 2000 (a kind of ultra-high-molecular-weight polyethylene), except for the outer 20 km which would be made of heat-resistant Zylon PBO. With a nominal payload mass of 14 tonnes, the Spectra/Zylon tether would weigh 1300 tonnes, or 90 times the mass of the payload.
>The second phase of the HASTOL study, published in 2001, proposed increasing the intercept airspeed to Mach 15–17, and increasing the intercept altitude to 150 km, which would reduce the necessary tether mass by a factor of three. The higher speed would be achieved by using a reusable rocket stage instead of a purely air-breathing aircraft. The study concluded that although there are no "fundamental technical show-stoppers", substantial improvement in technology would be needed. In particular, there was concern that a bare Spectra 2000 tether would be rapidly eroded by atomic oxygen; this component was given a technology readiness level of 2.
https://en.wikipedia.org/wiki/Skyhook_(structure)
I doubt one will ever be built due to the collision risk of something that big scything through an increasingly crowded LEO but its technically feasible

>>15441504
>The sky hook draws power from space via solar. So as opposed to a rocket that needs a massive amount of energy FROM EARTH to escape the gravity well we are tapping infinite energy in space to to that instead. The only fuel input we need from the planet is the fuel to lift the space plane.
This is false; lifting cargoes will lower the orbit of the skyhook
>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.
https://en.wikipedia.org/wiki/Skyhook_(structure)
Lifting such a large mass by electrically interacting with the magnetosphere is out so it will have to be the latter two. You can use high Isp electric thrusters since you're in vacuum but large amounts of propellant will still be needed. I like the concept but don't over sell it

>>15422627
HASTOLchads assemble