Historical research guide · 0005 · 2018
Breakthrough Propulsion Study: Assessing Interstellar Flight Challenges and Prospects
Marc G. Millis · Greason, Jeff · Stevenson, Rhonda
In one minute
Marc Millis, who ran NASA's Breakthrough Propulsion Physics project, wrote this first-year report with Jeff Greason and Rhonda Stevenson of the Tau Zero Foundation under a NASA grant. Its job is to build a fair scoreboard — a way to compare a fusion rocket, a laser-pushed sail and a space drive on the same terms. The team's answer is to convert every method into three shared quantities, energy spent, time taken and distance covered, because energy is, in their phrase, the fundamental currency of all motion. They then sort every known concept into three eras: precursors, infrastructure, and breakthroughs. The third era is the one this site is built around. Negative-mass propulsion, the Mach Effect Thruster, space drives, the dynamical Casimir effect, traversable wormholes, warp drive and faster-than-light communication all appear in a NASA-funded table with dates, references and an assigned analysis type. Millis argues that waiting for such prospects to arrive ready-made lets potentially revolutionary advances languish with little progress.
Connection
This is the NASA-funded document that puts warp drives, wormholes and space drives on the same evaluation sheet as sails and fusion rockets — the evidence-ladder discipline of chapter 1, applied by the agency itself. It also names the precise gap that chapters 3, 4 and 8 exist to close: for the warp drive the energy conversion equations already exist, but nothing yet resembles a propulsion system specific power.
From the source
Propulsion methods as different as a fusion rocket, a ground-based laser pushing a sail and a space drive can be compared equitably by converting each into three shared quantities — energy expended, mission duration and distance travelled — because energy is the fundamental currency of all motion.Section 1, Executive Summary; Section 2.2.1.2
Interstellar prospects sort into three distinct eras — precursors, infrastructure and breakthroughs — where the third is defined by requiring further advances in physics, and its infrastructure dependence cannot be determined until those concepts have been advanced to technology readiness level 3.Section 8.1
The era of breakthroughs is populated by named, dated, referenced concepts in a NASA-funded table: negative mass propulsion (1957), propellantless thrust via inertial fluctuations now called the Mach Effect Thruster (1994), spacedrives in general, the dynamical Casimir effect (2004), traversable wormholes (1988), warp drive (1994) and faster-than-light communication.Section 8.1.3; Table 4
Concepts that use spacetime or inertial frames as an effective reaction mass — negative mass propulsion, the Mach Effect Thruster, the warp drive — can be estimated by converting stored energy into spacecraft kinetic energy with a conversion efficiency and a propulsion system specific power. For the warp drive the energy conversion equations exist, but there are no equations yet that remotely resemble a specific power.Section 8.4.4, Spacetime and Inertial Frames as Effective Reaction Mass
The standard practice of waiting until new prospects emerge on their own, in a form ready to be evaluated by familiar mission trade studies, lets potentially revolutionary advances languish with little progress — which is why this NASA study deliberately includes breakthrough propulsion physics in scope.Section 2.2, Objective and Approach
Faster-than-light communication would shorten total mission duration by up to a year for every light-year of distance, so a communication breakthrough counts alongside a propulsion breakthrough in the same assessment.Section 8.1.3
The way in
https://ntrs.nasa.gov/citations/20180006480How to cite it
Marc G. Millis, Greason, Jeff, Stevenson, Rhonda (2018) Breakthrough Propulsion Study: Assessing Interstellar Flight Challenges and Prospects https://ntrs.nasa.gov/citations/20180006480