Epstein Drive

The Epstein Drive is a modified Fusion Drive invented by Solomon Epstein ^{Books • TV} around 130 years ago, in approximately 2213 AD BXT. It enabled humanity to travel beyond Earth and the inner planets and colonize the asteroid belt and the outer planets.

Background[]

The drive utilizes magnetic coil exhaust acceleration to increase drive efficiency, which enables spaceships to sustain thrust throughout the entire voyage. A ship fitted with the efficient Epstein drive is able to run the drive continuously for acceleration to its goal and then after flipping at about the halfway point is able to run the drive continuously during deceleration. Previous engine designs used propellant less efficiently and could not be run long enough to achieve the high velocities that the Epstein drive permitted.

Since its invention and up until the discovery of the Ring network, the Epstein drive remained the most advanced transportation technology humanity had access to.

Known models[]

S-250 Series Epstein Drive: A UN (United Nations) drive model used on Leonidas-class. This drive is older and less efficient than most current drive models.
S-400 Series Epstein Drive: A UN drive model used on Truman-class dreadnoughts.
Bush shipyards Black Ops supercooled Epstein drive - CODENAME Silversmith: A drive model manufactured on the Bush orbital shipyards orbiting Luna, and secretly used on the Amun-Ra-class stealth frigates owned by Protogen.
RT-10 'Kaminari' Epstein Drive: MCR (Martian Congressional Republic) drive model used on Donnager-class battleships.
RTF-B Series Epstein Drive: MCR drive model used on Scirocco-class assault cruisers.
RT6-B Epstein Drive: MCR drive model used on Morrigan-class patrol destroyers.
G-4000 Series Epstein Drive: A very large drive model used on the Nauvoo/Behemoth. They remained attached after becoming Medina Station.
Supercharged Destrier-4 High-Velocity Epstein Drive: The high performance drive model installed on the Razorback racing pinnace.

Drive Details[]

Using the information available at Atomic Rockets website^[1], the Epstein drive possesses the following performance characteristics (based upon the performance of Epstein's yacht):

Thrust: 1,000,000 N
Specific Impulse (i_sp): 1,100,000 seconds
Exhaust Velocity (v_e): 11,000,000 m/second (~3.7% of light speed;1,109,232m/s)
Mass Flow Rate (ṁ ): 0.09 kg/second
Thrust Power: 5.5 Terawatt
Engine's Thrust to Weight Ratio: ~140 ^{[Citation needed]}
Propellant mass fraction (yacht's mass fueled / mass empty): ~4

An alternative set of performance statistics has been suggested by the Tough SF website^[2], based on the performance of the Rocinante on-screen:

Thrust: 6,370,000 N
Specific Impulse (i_sp): 1,927,000 seconds
Exhaust Velocity (v_e): 18,900,000 m/second (6.8% of light speed)
Mass Flow Rate: 2.2 kg/second
Thrust Power: 60.2 Terawatt
Total power output: 96.8 Terawatt
Engine's Thrust to Weight Ratio: Presumably over 3 (The Roci has a dry TWR of 2.6)
Fusion type: D-He3 (1:2 mixture ratio)
Fusion pulse rate: "[what we see] can be achieved with as few as 10 pulses per second, or hundreds if possible"