I discovered that a rotating space elevator will work in theory. This particular design (just a few arbitrarily set values like altitude) is nearly 4000 km long, has a 50-tonne payload that it can grab from an aircraft flying 10 km high, and raise to orbit with 1-gee of acceleration. The docking window is just 29 seconds though - not much time to snag that tether. And the carbon-fibre tether would cost at least $1.6 billion at current market cost. After space qualification testing who knows how much it would cost. Then you've got to add a counterweight, plus solar wings, and two ProSEDS propellant-free stationkeeping engines at both ends of the Rotavator 'axle'. Pretty tough to imagine even in theory. But the launch capacity is fantastic, 50 tonnes per hour. To get enough material into space to manufacture my Starship Generations habitat sphere (8 million tonnes) would take less than 20 years. Compare that to 10,000 - 50,000 years at current launch capacity. I say unto thee, we shall develop a Rotavator someday !!! But Mars first...

Tether Dynamics Carbon Fibre Material Properties
hub orbit altitude 3950 km filaments per strand 12000
rotation rate 0.000251 rps filament diameter 5.1 micrometers
rotation time 66.381 minutes filament section area 2.04276E-11 m^2
overall radius 3940000 m strand section area 2.45131E-07 m^2
overall radius 3940 km strand diameter 0.000558677 m
orbit velocity 6215 m/s length per unit mass 2.25 m/g
tip velocity 6215 m/s density 1.81 g/cubic cm
tip acceleration 10 m/s^2 specific surface area 0.5 sq.m/g
tip g-force 0.999 g's ultimate tensile stress 5.65 Gpa
docking window 29 sec elongation percent (break) 1.8 percent
mass of payload 50000 kg elastic modulus 290 GPa
weight of payload 4.9E+05 N thermal conductivity 15 W/m-K
tip section area 8.7E-05 m^2 melting point of carbon 3800 deg.K
number of tip strands 532 carbon electron affinity 1.00E-04 Ohm-m
cost of 10 mm thick sheet 48,400 US$/sq.m
Payload Tether Support Stresses cost per unit volume 4,840,000 US$/cu.m
number of strands at root 1000
number of strands at tip 532 Rotational Energy
root area 0.000245131 m^2 KE of tether 61253908368 J
tip area 0.000130397 m^2 KE of projectile 9.65773E+11 J
radius of centroid 985000 m KE of counterweight 1.02703E+12 J
velocity of center of mass 1554 m/s^2 Total Kinetic Energy 2.05405E+12 J
centripetal acceleration 2.45 m/s^2 Solar Radiation 1350 W/m^2
mass of tether 50739.7914 kg
weight of tether + payload 6.1E+05 N
stress at root of tether 2507283724 Pa
fraction of tensile stress 0.443767031
tether elongation 0.799 percent
whip wavelength 31471.958 m
Volume of Tether Material 321.9390351 m^3
Cost of Tether Material 1,558,184,930 U.S. $