OK!

Too bad I couldn't draw you a couple of diagrams to help me explain.
I'll try to be as articulate and instructive as possible, regardless.

SITUATION: (1) Take a [theoretical] platform, more than 18 meters long, and park it into low Earth-orbit where Earth's gravitational acceleration is exactly 9.0 meters/second squared. Somewhere between 100-300 kilometers up.

(2) Take that platform [which has an electric power supply] and mount two 9.0 meter-long pendulum's beneath, more than 18 meters apart so they won't strike each other.

(3) Each pendulum will mount a massive lead weight on the pendulum bob.

(4) Each pendulum will have an electric shunt-motor that is designed
to accelerate each pendulum [ON THEIR DOWN SWING], over an arc of 90 degrees, upto an angular-velocity of exactly 4.5 meters/second...at which time each electric-motor deliberately cuts out.

(5) The pendulums will be accelerated
from zero velocity [relative to their platforms] to 4.5 meters/second in one
second intervals of time.

(6) That means, each pendulum arm,
will be HORIZONTAL [parallel to Earth's surface down below] at ZERO VELOCITY, a moment before the shunt motors kick in to start accelerating the pendulums; and VERTICAL [perpendicular to Earth's surface] when the maximum angular-velocity of
4.5 meters/second is attained...at the "bottom" of the DOWN SWING.

(7) At the bottom of the DOWN SWING,
each pendulum arm being vertical to the Earth's surface far below,
each of those pendulums has MAXIMUM ANGULAR-MOMENTUM.
[and that 90 degree arc-swing only takes one second]

(8) As each pendulum enters its UP SWING, of 90 degrees. to return to a horizontal position, relative to the Earth's surface, Earth's gravity should 'kill' all of the ANGULAR-MOMENTA of those pendulum's by converting all the ANGULAR KINETIC ENERGY [each pendulum has] into POTENTIAL ENERGY.
And that taking only another second to accomplish.
One second (accelerating to 4.5 meters/second) + one second (negative acceleration to zero) = two seconds to traverse 180 degrees ( 90 degrees + 90 degrees).

(9) However! Since the two pendulums, working in concert, each swing 180 degree arcs, in two seconds time, and then reverse to repeat the process over and over again [until the shunt motors run out of electric poower] would there
be a "net gain" of momentum for the entire platform?
[REMEMBER! Pendulums swinging 180 degrees generate centripetal force,
most of the force vectors being in the downward direction.]
a^2 + b^2 = c^2

a^2 could be the HORIZONTAL [relative to Earth's surface] component,
equaling the platform's orbital velocity squared: (7,800 m/s)^2

b^2. Could the VERTICAL [relative to the Earth's surface] component be greater than zero for the entire platform as a result of possible NET "momentum-gain" gained by its pendulums?

c^2. Is it possible then that c^2
could be greater than a^2 as a result?

Jacob