TL;DR: For a Starship‑class stack (~5,000 t at liftoff), a “lift assist” that adds only 80–150 m/s early can yield +5–13% LEO payload depending on site. Move the same vehicle to a near‑equatorial African highland and combine with a best‑case spring, and you add ~20 t to LEO and save tens of tons of propellant on GEO missions via plane‑change avoidance. Every bit matters—and matters a lot.

0) Assumptions (so the numbers are reproducible)

• Vehicle mass at liftoff: 5,000,000 kg (Starship + Super Heavy class).
• Stage performance model (back‑of‑envelope but consistent):
  • Booster: Isp ≈ 330 s, prop ≈ 3,300 t, dry ≈ 200 t.
  • Ship: Isp ≈ 375 s, prop ≈ 1,200 t, dry ≈ 150 t.
• Pad‑to‑LEO Δv budget (including gravity/drag): ~9.4 km/s (baseline).
• Rotation boost difference: Equator vs. Starbase (~26°N) ≈ +47 m/s at the equator.
• Equatorial GEO circularization plane‑change advantage (apogee, combined burn): ≈ 305 m/s saved vs. 26°N.
• High‑plateau altitude credit (thin air, lower back‑pressure) as a small early‑phase Δv equivalent: ~10–20 m/s (illustrations use 20 m/s).

1) The three scenarios

Why not a literal stadium‑sized steel spring? Because elastic energy density of steel is small. Best practical “springs” are modular: electromagnetic segments, hydraulics, flywheels/SMES, and high‑strain composite tendons—charged slowly, discharged fast, shaped by control.

2) The Δv ledger (what “free” do we get?)

• Maglev lift: ~+80 m/s early.
• Magnificent spring: ~+150 m/s early (world‑class engineering and containment).
• Equator vs. Starbase (~26°N): +47 m/s (rotation).
• Highland altitude: ~+10–20 m/s Δv‑equivalent from lower air density/back‑pressure in the dirtiest seconds.
• GEO from equator: save ~305 m/s at apogee by avoiding the 26° plane‑change penalty (see §5).

3) How much payload does that buy? (LEO)

Using the consistent two‑stage model above, here’s what falls out. Numbers are indicative, not promises; what matters is the pattern.

Read this as: the same vehicle, with a modest early push and a better site, picks up double‑digit tons to LEO. That is the opposite of “small.”

4) Design sanity checks (stroke, force, energy)

• Stroke (v²/2a):
  • 80 m/s at +1 g → ~320 m.
  • 150 m/s at +2 g → ~563 m; at +3 g → ~375 m.
• Average force (M·Δv / t):
  • 80 m/s over 4 s → ~100 MN.
  • 150 m/s over 4 s → ~188 MN.
• Energy (½ M v²):
  • 80 m/s → 16 GJ (~4.4 MWh).
  • 150 m/s → 56 GJ (~15.6 MWh).

  Grid energy is easy; the hard part is power for a few seconds. That’s why the spring pack exists: charge slowly, dump fast, shape the force.

5) GEO is where equator becomes mind‑bending

From ~26°N (Starbase), a GEO mission must remove ~26° of inclination. If you do the plane change smartly at apogee and combine it with circularization, the extra cost is ~305 m/s versus launching from the equator.

What does 305 m/s mean in propellant? For an upper stage with Isp ≈ 375 s:

• Per 200 t of post‑burn mass (dry + payload), the apogee burn at the equator needs ~99 t of prop, while the same at Starbase needs ~125 t. That’s ~26 t saved—at apogee, every single mission.
• Scale linearly: 400 t → ~52 t saved; 800 t → ~103 t saved.

Pair that with a 150 m/s spring at liftoff and a highland site, and you’re stacking hundreds of m/s of budget relief across the mission. In a refueling architecture, that is fewer tanker flights or more payload to GEO.

6) Materials reality check (why “magnificent” still isn’t magic)

• Today‑practical spring packs (steel/titanium + composites + EM motors): expect effective elastic energy density in the ~1–10+ kJ/kg range. That’s plenty for assist, not for “sling to orbit.”
• Lab‑dream materials (bulk metallic glass, high‑strain CFRP, someday CNT/graphene in bulk) can push to ~10–30+ kJ/kg practical. That buys ~150 m/s‑class assists at megastructure scale. Still, engines do the real trip.

7) Safety, control, and “don’t snap the rocket”

• Many small modules > one giant spring: redundancy and graceful aborts.
• Jerk‑limited S‑curves: smooth rise/hold/fall of force; engines co‑throttle to keep total g on‑spec.
• Containment/dampers: any unused energy ends in brakes, not in “bounce‑back boostback.”

8) Bottom line

• Maglev lift (~80 m/s): already worth ~+5% LEO payload at Starbase, more at the equator.
• Magnificent spring (~150 m/s): with world‑class engineering, you’re in the ~+9–13% LEO payload band depending on site.
• Equatorial Africa highland + spring: roughly +20 t to LEO for the same vehicle, and ~25–100+ t propellant saved at GEO apogee (mission‑dependent). That’s “every bit matters” made visible.
• Engines still do the job: the spring doesn’t replace propulsion; it deletes some of the ugliest seconds and hands you payload for it.

Stage Zero can be a battery. Charge it slowly. Release it politely. Between a better pad and a better latitude, you don’t change physics—you let physics change your payload.