Nuclear Pulse Propulsion — Orion Drive Simulator

Pulse Unit

Yield per pulse 3.0 kt

Pulse interval 1.20 s

Shock Absorber

Strut stiffness k 4.0 MN/m

Damping c 1.20 MN·s/m

Flight Data

Ship Δv

0.0 m/s

Pulses fired

Peak crew load

0.0 g

Ship mass

2,000.0 t

Impulse / pulse

— N·s

Strut travel

0.0 cm

How it works

Each pulse unit is a small fission charge dropped behind the pusher plate and detonated a set distance astern. The expanding plasma slams into the plate; an ablated surface layer carries momentum onto it. The impulse delivered is modelled from the pulse-unit's yield with a momentum-coupling coefficient C_m (the historical Project Orion feasibility studies estimated C_m on the order of 10³–10⁴ m/s for a polyethylene-coated plate):

E_pulse = Y_kt · 4.184×10¹² J
J = C_m · sqrt(2 · η · E_pulse · m_u)   (impulse, N·s)
v_plate += J / m_plate                  (instant kick)

That kick would break a human spine if applied directly to the crew — Orion's real innovation was the two-stage pneumatic/mechanical shock absorber between the pusher plate and the ship. It is modelled here as a damped spring linking two masses:

m_p·v_p' = −k·x − c·(v_p − v_s)
m_s·v_s' = +k·x + c·(v_p − v_s)
x' = v_p − v_s              (strut compression)

Between the kick and the next detonation, momentum is conserved (m_p·v_p + m_s·v_s = const): the spring-damper spreads the plate's sudden velocity spike over a fraction of a second, so the crew module feels a bounded acceleration instead of a shock. Raise the stiffness or lower the damping and the peak crew load climbs; raise the damping enough and the strut critically damps before the next pulse arrives.

Yield per pulse — energy of each nuclear charge; sets impulse magnitude.
Pulse interval — time between detonations in auto-fire.
Strut stiffness / damping — the shock absorber's spring constant and damping coefficient.
Detonate one pulse — fire a single charge and watch the strut compress and relax.

Real-world relevance: this is the propulsion concept studied by General Atomics under Project Orion (1958–1965) and revisited in modern mission-design papers as one of the few near-term technologies offering both high thrust and high specific impulse (Isp on the order of 10,000 s) for crewed deep-space missions.

💥 PULSE DETONATED

Pusher plate Crew module Pulse unit charge

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