Project Daedalus

The Ship view is the 190-metre stack drawn to the report's dimensions, drive running, Barnard's Star a red point far ahead. Stage 1 is the 50-metre reaction chamber, three superconducting coil rings and six spheres holding 46,000 tonnes of cryogenic fuel; stage 2 repeats the design at three-quarter scale; forward of both sit the payload bay, two 5-metre telescopes, the ring of 18 sub-probes, the warden robots, and the beryllium erosion disc, drawn thick enough to see and labelled honest about it. Every label is clickable and carries its number from the report.

The Pulse view goes inside the stage-1 chamber, where the whole scheme lives or dies. At real speed 250 detonations a second merge into a continuous cyan exhaust; at one pulse a second you can follow individual pellets; in anatomy mode one four-millisecond cycle stretches across six seconds: the frozen pellet crosses the chamber, the diode ring fires its relativistic electrons, the surface ablates, the core lights, and the magnetic nozzle, a field, not metal, gathers the fireball and throws it backward at 10,600 km/s. Toggles strip the beams and field lines out so you can see what each part does.

The Voyage view is the mission as one draggable curve: the rocket equation climbing through 2.05 years of stage-1 burn to 7.1% of c, staging, 1.76 more years to 12.2%, then the long flat coast to a red encounter band about three days wide near year 50. A distance strip tracks the crossing from Sun to Barnard's Star; readouts derive velocity, mass, acceleration and signal delay from the same arithmetic. The braking-ledger toggle draws the case for the flyby: stopping multiplies the launch mass roughly thirty-one-fold, and the published stop-and-stay design runs past ten million tonnes.

The File view lays the case out card by card, 1973 to 2024: the thirteen volunteers, the 1978 supplement, the helium-3 problem and its Jupiter aerostats, NIF's one-shot-a-day ignition, the target's planets dissolving in 1973 and returning in 2024 as Barnard b, and the two descendants, Icarus and Starshot. Below hang the two verdict cards at equal size: what the study proved, and what fifty years have not built. This site's editorial stance, rendered as layout.

This station's propulsion line opens with INST-11 Project Orion: 1958, throw whole atomic bombs out the back and ride the blasts. Daedalus is that argument's direct sequel and its coming of age: the same pulse-propulsion physics, with "a bomb a second" traded for 250 fusion pellets a second imploded by electron beams, and the steel pusher plate traded for a magnetic field held open by superconducting coils. From 1973 to 1978 thirteen volunteers of the British Interplanetary Society, engineers with day jobs, spent five years of evenings computing it into a two-hundred-page engineering study, published as a JBIS supplement. It remains the first starship ever worked all the way through.

There is a deeper reason to pick it: Daedalus is the first time "is interstellar flight possible" received an engineering answer rather than a science-fiction one, and its central evidence happens to be entirely computable. The velocity curve is the rocket equation; the cost of stopping is the same equation run backward; the state of ignition has NIF's measured 2022 numbers to check against. So this bench neither celebrates the starship nor mocks it. It draws the 190-metre stack to the report's dimensions and opens it part by part, slows the four-millisecond pulse cycle to watchable speed, draws fifty years as a draggable curve, and hangs "what the study proved" and "what fifty years have not built" as verdict cards at equal size.

One equation runs the whole bench, and the panel tags every number as study, physics, modelled or reading.

Δv = vₑ ln(m₀/m₁) · stage 1: 46,000 t over 2.05 yr at vₑ = 10,600 km/s → 0.071 c · stage 2: 4,000 t over 1.76 yr at 9,210 km/s → 0.122 c · d = ∫v dt → 5.9 ly ≈ year 50 · stop: ×e^(Δv/vₑ) ≈ 31

The curve is Tsiolkovsky, pinned. Each stage burns at constant mass flow, so velocity follows the ideal rocket equation; a scale factor within a few percent of unity lands the curve exactly on the study's two milestones, absorbing the report's finer mission profile. Distance is the numeric integral, and arrival at 5.9 light-years falls where the study said it would: near year fifty.

The readouts derive, they do not decorate. Mass falls linearly with each burn and drops 1,690 tonnes at staging; acceleration is thrust over mass and never exceeds about 0.014 g; the signal-delay readout is the distance in light-years read as years. Scrub the clock and every number moves together, because they are all the same arithmetic.

The braking ledger runs the equation backward. Killing 12.2% of c with the study's own exhaust velocity costs a mass ratio of e^(Δv/vₑ) ≈ 31, so the 54,000-tonne flyby becomes a ~1.7-million-tonne stopping mission before the extra structure makes it worse. That idealisation is tagged MODELLED and drawn beside the published number: Freitas's 1980 REPRO, over 10 million tonnes. The three bars share a log scale, and the flyby explains itself.

The pulse cycle follows the report's anatomy. Inject, converge, burn, flush: the phase structure and the 250 Hz rate are the study's; the pacing is compressed or stretched to watchable speed and the dial says which is in force. The 2022 NIF result sits in the evidence table as the measured state of the art: ignition demonstrated, at one shot a day, with lasers, on the ground.

And the drawing confesses. The ship's proportions follow the report, but the shield is thickened from 7 mm to visible metres, the plumbing is schematic, and the plume is art directed by the numbers rather than a plasma solve. Every liberty is disclosed in the panel's own words, because the difference between a diagram and a painting is exactly what this instrument is about.

The masses, burns and milestones are quoted from the 1978 report; the curve, the integrals and the braking arithmetic are physics you can audit; the drawing's liberties are disclosed as modelling choices; and the NIF benchmark is a measured laboratory result. What this bench refuses to do is finish the study's sentence. "Feasible in principle" has read, for fifty years, either as the licence for every interstellar programme since or as the politest impossibility proof ever published. Both verdict cards hang in the file, and every number on this bench serves both.

One clock, one ledger and three drive speeds, each a position from the report, not a mood.

• The mission clock. Fifty years on one slider. The first 3.81 years contain every newton the ship will ever feel; the remaining forty-six contain the mission. Scrub it once and you understand the study's quietest finding: the hard engineering is not thrust, it is time.
• The braking ledger. One toggle prices the difference between visiting a star and pausing at one: thirty-one times the launch mass, idealised, or Freitas's ten million tonnes, published. The flyby stops looking like a compromise and starts looking like the entire reason the numbers close.
• Real / 1-per-second / anatomy. The same drive at three clock speeds: a continuous cyan weather, a countable pulse, a six-second autopsy of four milliseconds. The study's whole propulsion argument lives in the anatomy pass; the other two speeds show why it adds up to a starship.
• Beams and field lines. Strip the electron beams out and the pellet crosses the chamber inert; strip the field and the fireball has no nozzle. Two toggles isolate the two inventions the entire 54,000 tonnes exists to carry.
• Labels. Ten clickable parts on the ship, six in the chamber, each carrying its figure from the report. The stack stops being a silhouette and becomes a bill of materials, which is what it always was.

Five claims about the starship, with who argues each and where it lands. One leads and is fifty years old; three are live and share the arithmetic; one is a caution about ratios.

1. Let the clock run from launch without touching anything. The status bar walks BOOST 1, STAGING, BOOST 2, CRUISE while the ship view's drive burns and dies. Two years to throw away a fleet's worth of fuel, two more for the second stage, then silence at 12.2% of c. The mission's entire active life fits in the first four seconds of playback.
2. Open the anatomy pass and watch one pellet die. Injection, the converging beams, the flash, the field-guided flush. Then switch to REAL and watch 250 of those a second merge into weather. The jump between those two clock speeds is the jump the study asks of engineering: NIF fires once a day.
3. Drag the scrubber to year 25 and read the verdict. Mid-cruise: the telescopes have just started surveying a system nobody on Earth can see as well, the wardens are patrolling, and the signal delay reads two and a half years. Nothing is happening, and nothing may interrupt: this is what most of a starship mission is.
4. Park the clock on the encounter and count the days. The red band near year 50 is about three days wide. Half a century of flying, sized against it on the same axis. Then find the probe window just before it: the study's answer, and the one piece of Daedalus the following fifty years actually delivered.
5. Toggle the braking ledger and read the three bars aloud. Fifty-four thousand tonnes to wave; one point seven million to stop, idealised; ten million published. The log scale is doing its best and the bars still will not fit politely. This is the rocket equation's opinion of staying, and it is the whole case for the flyby.
6. End in the File and read the two cards. A study that proved the crossing violates nothing, and a fifty-year ledger of technologies that have not arrived. Between them sits the target itself, whose planets dissolved in 1973 and returned in 2024. Every instrument on this station eventually reaches a fork like this; this is the one where both tines are engineering.

The honest line between what the study designed, what physics derives, what is modelled here, and what is a reading:

In one line: the vehicle, the drive and the mission milestones are quoted from the 1978 BIS final report and tagged as the study's design; the velocity curve, the distance integral, the braking arithmetic and the NIF benchmark are physics and measurement you can audit; the drawing's proportions, plume art and slow-motion pacing are disclosed modelling choices; and whether "feasible in principle" reads as a licence or as the politest impossibility proof is a reading, on which the report's heirs and its sceptics have disagreed for fifty years, which is precisely why this instrument belongs on this station. Drag the fifty years and decide for yourself.

• Bond, A. & Martin, A. R. (eds.), "Project Daedalus: The Final Report on the BIS Starship Study", Journal of the British Interplanetary Society Supplement, 1978. Every vehicle, propulsion and mission number on this bench: masses, burn times, exhaust velocities, thrusts, the 250 Hz pellet rate, the payload, the shield, the wardens, the Jupiter aerostats, the milestones.
• Martin, A. R. & Bond, A., the Daedalus papers in JBIS vols. 29-31 (1976-1978): the propulsion, structure and navigation studies the supplement collects.
• Freitas, R. A. Jr., "A Self-Reproducing Interstellar Probe", JBIS 33, July 1980: the REPRO deceleration-and-factory variant exceeding 10 million tonnes, quoted in the braking ledger.
• Lawrence Livermore National Laboratory, National Ignition Facility results of 5 December 2022 (announced 13 December 2022): first laboratory fusion shot with target gain above 1 (~1.5), the bench's measured ignition benchmark.
• González Hernández, J. I. et al., "A sub-Earth-mass planet orbiting Barnard's star", Astronomy & Astrophysics, 2024 (ESPRESSO/VLT): Barnard b confirmed; with the 1973 resolution of van de Kamp's astrometric planets as instrumental artifacts (Gatewood & Eichhorn; Hershey).
• Project Icarus (2009-, British Interplanetary Society / Icarus Interstellar) and Breakthrough Starshot (2016-): the study's two live descendants, cross-referenced to INST-20.
• The site wiki cluster: the British Interplanetary Society, Project Orion, nuclear pulse propulsion, Barnard's Star, Breakthrough Starshot.