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Project Daedalus

For other uses, seeDaedalus Project (disambiguation).

Project Daedalus(named afterDaedalus,theGreek mythologicaldesigner who crafted wings for human flight) was a study conducted between 1973 and 1978 by theBritish Interplanetary Societyto design a plausibleuncrewedinterstellar probe.[1]Intended mainly as a scientific probe, the design criteria specified that the spacecraft had to use existing or near-future technology and had to be able to reach its destination within a human lifetime.Alan Bondled a team of scientists and engineers who proposed using afusion rocketto reachBarnard's Star5.9light yearsaway. The trip was estimated to take 50 years, but the design was required to be flexible enough that it could be sent to any other target star.

Daedalus spacecraft concept

All the papers produced by the study are available in a BIS book,Project Daedalus: Demonstrating the Engineering Feasibility of Interstellar Travel.[2]

Concept

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Daedalus would be constructed in Earth orbit and have an initial mass of 54,000tonnesincluding 50,000 tonnes of fuel and 500 tonnes of scientific payload. Daedalus was to be a two-stage spacecraft. The first stage would operate for two years, taking the spacecraft to 7.1% oflight speed(0.071c), and then after it was jettisoned, the second stage would fire for 1.8 years, taking the spacecraft up to about 12% of light speed (0.12c), before being shut down for a 46-year cruise period. Due to the extreme temperature range of operation required, from nearabsolute zeroto 1600 K, theengine bellsand support structure would be made ofmolybdenumalloyed withtitanium,zirconium,andcarbon,which retains strength even atcryogenic temperatures.A major stimulus for the project wasFriedwardt Winterberg'sinertial confinement fusiondrive concept,[1][3]for which he received the Hermann Oberth gold medal award.[4]

This velocity is well beyond the capabilities ofchemical rocketsor even the type ofnuclear pulse propulsionstudied duringProject Orion.According to Dr.Tony Martin,controlled-fusion engine and thenuclear–electric systemshave very lowthrust,equipment to convert nuclear energy into electrical has a large mass, which results in smallacceleration,which would take a century to achieve the desired speed; thermodynamic nuclear engines of theNERVAtype require a great quantity of fuel,photon rocketshave to generate power at a rate of 3×109W per kg of vehicle mass and require mirrors withabsorptivityof less than 1 part in 106,interstellar ramjet's problems are tenuous interstellar medium with a density of about 1 atom/cm3,a large diameter funnel, and high power required for its electric field. Thus the only suitable propulsion method for the project wasthermonuclear pulse propulsion.[5][6][7]

Daedalus would be propelled by afusion rocketusing pellets of adeuterium/helium-3mix that would be ignited in the reaction chamber byinertial confinementusingelectron beams.The electron beam system would be powered by a set ofinduction coilstrapping energy from theplasmaexhaust stream. 250 pellets would be detonated per second, and the resulting plasma would be directed by amagnetic nozzle.The computed burn-up fraction for the fusion fuels was 0.175 and 0.133 producing exhaust velocities of 10,600 km/s and 9,210 km/s respectively. Due to scarcity of helium-3 on Earth, it was to be mined from the atmosphere ofJupiterby largehot-air balloonsupported robotic factories over a 20-year period, or from a less distant source, such as theMoon.[8]

The second stage would have two 5-metreoptical telescopesand two 20-metreradio telescopes.About 25 years after launch these telescopes would begin examining the area around Barnard's Star to learn more about any accompanying planets. This information would be sent back to Earth, using the 40-metre diameter second stageengine bellas a communications dish, and targets of interest would be selected. Since the spacecraft would not decelerate, upon reaching Barnard's Star, Daedalus would carry 18 autonomous sub-probes that would be launched between 7.2 and 1.8 years before the main craft entered the target system. These sub-probes would be propelled bynuclear-poweredion drivesand would carry cameras,spectrometers,and other sensory equipment. The sub-probes would fly past their targets, still travelling at 12% of the speed of light, and transmit their findings back to the Daedalus' second stage, mothership, for relay back to Earth.

The ship's payload bay containing its sub-probes, telescopes, and other equipment would be protected from theinterstellar mediumduring transit by aberylliumdisc, up to 7 mm thick, weighing up to 50 tonnes. This erosion shield would be made from beryllium due to its lightness and high latent heat of vaporisation. Larger obstacles that might be encountered while passing through the target system would be dispersed by an artificially generated cloud of particles, ejected by support vehicles called dust bugs about 200 km ahead of the vehicle. The spacecraft would carry a number ofrobotwardens capable of autonomously repairing damage or malfunctions.

Specifications

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Overall length: 190 metres

Payload mass: 450 tonnes

First stage: Second stage:
Empty mass: 1,690 tonnes (at staging) 980 tonnes (at cruise speed)
Propellant mass: 46,000 tonnes 4,000 tonnes
Engine burn time: 2.05 years 1.76 years
Thrust: 7,540,000newtons 663,000 newtons
Engine exhaust velocity: 10,600,000 m/s 9,210,000 m/s
Delta-V 35,000,000 m/s (0.117c) 13,000,000 m/s (0.0432c)

Variants

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A quantitative engineering analysis of aself-replicatingvariation on Project Daedalus was published in 1980 byRobert Freitas.[9]The non-replicating design was modified to include all subsystems necessary for self-replication. Use the probe to deliver a seed factory, with a mass of about 443 metric tons, to a distant site. Have the seed factory replicate many copies of itself on-site, to increase its total manufacturing capacity, then use the resulting automated industrial complex to construct probes, with a seed factory on board, over a 1,000-year period. Each REPRO would weigh over 10 million tons due to the extra fuel needed to decelerate from 12% oflightspeed.

Another possibility is to equip the Daedalus with amagnetic sailsimilar to the magnetic scoop on aBussard ramjetto use the destination starheliosphereas a brake, making carrying deceleration fuel unnecessary, allowing a much more in-depth study of the star system chosen.

See also

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Further reading

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  • K. F. Long (2012). "Project Daedalus".Deep Space Propulsion: A Roadmap to Interstellar Flight.Springer.pp.190–197.ISBN9781461406075.

References

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  1. ^abProject Daedalus Study Group: A. Bond et al.,Project Daedalus – The Final Report on the BIS Starship Study,JBIS Interstellar Studies, Supplement 1978
  2. ^A. Bond et al.,Project Daedalus: Demonstrating the Engineering Feasibility of Interstellar Travel
  3. ^F. Winterberg, "Rocket propulsion by thermonuclear microbombs ignited with intense relativistic electron beams", Raumfahrtforschung 15, 208-217 (1971).
  4. ^Winterberg isHermann OberthGold Medalist,Physics Today, December 1979
  5. ^"Project Daedalus: The Propulsion System Part 1; Theoretical considerations and calculations. 2. Review of Advanced Propulsion Systems".Archived fromthe originalon June 28, 2013.
  6. ^Bond, A.; Martin, A. R. (January 1, 1978)."Project Daedalus".Journal of the British Interplanetary Society Supplement.31:S5–S7.Bibcode:1978JBIS...31S...5B– via NASA ADS.
  7. ^"Project Daedalus – Origins".Archived fromthe originalon 26 October 2009 – via GeoCities.
  8. ^Helium-3#Extraterrestrial abundance
  9. ^Freitas, Robert A. Jr. (July 1980)."A Self-Reproducing Interstellar Probe".J. Br. Interplanet. Soc.33:251–264.Bibcode:1980JBIS...33..251F.
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