Editing Project Daedalus

{{Short description|1970s proposal for an interstellar probe}}
{{Other uses|Daedalus Project (disambiguation)}}
[[File:Daedalus Spaceship concept.jpg|thumb|240 px|Daedalus spacecraft concept]]

'''Project Daedalus''' (named after [[Daedalus]], the [[Greek mythology|Greek mythological]] designer who crafted wings for human flight) was a study conducted between 1973 and 1978 by the [[British Interplanetary Society]] to design a plausible [[uncrewed spacecraft|uncrewed]] [[interstellar probe]].<ref name="study">Project Daedalus Study Group: A. Bond et al., ''Project Daedalus – The Final Report on the BIS Starship Study'', JBIS Interstellar Studies, Supplement 1978</ref> 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 Bond (engineer)|Alan Bond]] led a team of scientists and engineers who proposed using a [[fusion rocket]] to reach [[Barnard's Star]] 5.9 [[light year]]s away.  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.

All the papers produced by the study are available in a BIS book, ''Project Daedalus: Demonstrating the Engineering Feasibility of Interstellar Travel''.<ref name="book">A. Bond et al., [https://bis-space.com/shop/product/project-daedalus-demonstrating-the-engineering-feasibility-of-interstellar-travel/ ''Project Daedalus: Demonstrating the Engineering Feasibility of Interstellar Travel''] </ref>

==Concept==
Daedalus would be constructed in Earth orbit and have an initial mass of 54,000 [[tonnes]] including 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% of [[light speed]] (0.071 ''c''), 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 (0.12 ''c''), before being shut down for a 46-year cruise period. Due to the extreme temperature range of operation required, from near [[absolute zero]] to 1600 K, the [[Bell nozzle|engine bells]] and support structure would be made of [[molybdenum]] alloyed with [[titanium]], [[zirconium]], and [[carbon]], which retains strength even at [[cryogenic temperature]]s. A major stimulus for the project was [[Friedwardt Winterberg]]'s [[inertial confinement fusion]] drive concept,<ref name="study"/><ref>F. Winterberg, "Rocket propulsion by thermonuclear microbombs ignited with intense relativistic electron beams", Raumfahrtforschung 15, 208-217 (1971).</ref> for which he received the Hermann Oberth gold medal award.<ref>Winterberg is [[Hermann Oberth]] Gold Medalist, [https://dx.doi.org/10.1063/1.2995324 Physics Today, December 1979]</ref>

This velocity is well beyond the capabilities of [[chemical rocket]]s or even the type of [[nuclear pulse propulsion]] studied during [[Project Orion (nuclear propulsion)|Project Orion]]. According to Dr. [[Donald A. Martin|Tony Martin]], controlled-fusion engines and the [[Nuclear electric rocket|nuclear–electric systems]] have very low [[thrust]] because equipment to convert nuclear energy into electrical has a large mass which results in small [[acceleration]], taking a century to achieve the desired speed; thermodynamic nuclear engines of the [[NERVA]] type require a great quantity of fuel. [[Photon rocket]]s have to generate power at a rate of 3{{e|9}} W per kg of vehicle mass and require mirrors with [[Absorptance|absorptivity]] of less than 1 part in 10<sup>6</sup>. [[Interstellar ramjet]]'s problems are the tenuous interstellar medium with a density of about 1 atom/cm<sup>3</sup>, a large diameter funnel, and high power required for its electric field. Thus the only suitable propulsion method for the project was [[Nuclear pulse propulsion|thermonuclear pulse propulsion]].<ref>{{Cite web|url=http://daedalus-zvezdolet.narod.ru/doceng/07eng.doc|archiveurl=https://web.archive.org/web/20130628001133/http://daedalus-zvezdolet.narod.ru/doceng/07eng.doc|url-status=dead|title=Project Daedalus: The Propulsion System Part 1; Theoretical considerations and calculations. 2. Review of Advanced Propulsion Systems|archivedate=June 28, 2013}}</ref><ref>{{Cite journal|url=https://ui.adsabs.harvard.edu/abs/1978JBIS...31S...5B/abstract|title=Project Daedalus|first1=A.|last1=Bond|first2=A. R.|last2=Martin|date=January 1, 1978|journal=Journal of the British Interplanetary Society Supplement|volume=31|pages=S5–S7|bibcode=1978JBIS...31S...5B |via=NASA ADS}}</ref><ref>{{Cite web|url=http://geocities.com/televisioncity/2049/DAEDALUS.HTM|url-status=dead|archive-url=https://web.archive.org/web/20091026192110/http://geocities.com/televisioncity/2049/DAEDALUS.HTM|title=Project Daedalus – Origins|archive-date=26 October 2009|via=GeoCities}}</ref>

Daedalus would be propelled by a [[fusion rocket]] using pellets of a [[deuterium]]/[[helium-3]] mix that would be ignited in the reaction chamber by [[inertial confinement fusion|inertial confinement]] using [[electron beam]]s. The electron beam system would be powered by a set of [[induction coils]] trapping energy from the [[plasma (physics)|plasma]] exhaust stream. 250 pellets would be detonated per second, and the resulting plasma would be directed by a [[magnetic nozzle]]. The computed burn-up fraction for the fusion fuels was 0.175 and 0.133 producing exhaust velocities of 10,600&nbsp;km/s and 9,210&nbsp;km/s respectively. Due to scarcity of helium-3 on Earth, it was to be mined from the atmosphere of [[Jupiter]] by large [[hot-air balloon]] supported robotic factories over a 20-year period, or from a less distant source, such as the [[Moon]].<ref>[[Helium-3#Extraterrestrial abundance]]</ref>

The second stage would have two 5-metre [[optical telescope]]s and two 20-metre [[radio telescope]]s. 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 stage [[Bell nozzle|engine bell]] as 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 by [[Nuclear electric rocket|nuclear-powered]] [[ion drive]]s and would carry cameras, [[spectrometer]]s, 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 the [[interstellar medium]] during transit by a [[beryllium]] disc, up to 7&nbsp;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&nbsp;km ahead of the vehicle. The spacecraft would carry a number of [[robot]] wardens capable of autonomously repairing damage or malfunctions.

==Specifications==
*Overall length: 190 metres
*Payload mass: 450 tonnes

{| class="wikitable"
! Property
! 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
| 7,540,000 [[newton (unit)|newton]]s || 663,000 newtons
|-
| Engine exhaust velocity
| 10,600,000&nbsp;m/s || 9,210,000&nbsp;m/s
|-
|[[Delta-V]]
|35,000,000 m/s (0.117c)
|13,000,000 m/s (0.0432c)
|}

==Variants==
A quantitative engineering analysis of a [[self-replicating spacecraft|self-replicating]] variation on Project Daedalus was published in 1980 by [[Robert Freitas]].<ref>{{cite journal| first=Robert A. Jr.| last=Freitas| title=A Self-Reproducing Interstellar Probe| journal=J. Br. Interplanet. Soc.| volume=33|date=July 1980| pages=251–264| url=http://www.rfreitas.com/Astro/ReproJBISJuly1980.htm|bibcode = 1980JBIS...33..251F }}</ref> 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% of [[lightspeed]].

Another possibility is to equip the Daedalus with a [[magnetic sail]] similar to the magnetic scoop on a [[Bussard ramjet]] to use the destination star [[heliosphere]] as a brake, making carrying deceleration fuel unnecessary, allowing a much more in-depth study of the star system chosen.

== See also ==
{{Portal|Spaceflight|Space}}
* [[Breakthrough Starshot]]
* [[Project Icarus (interstellar)|Project Icarus]]
* [[Project Longshot]]
* [[Enzmann starship]]

== Further reading ==
*{{cite book
 |author1=K. F. Long  |year=2012
 |title=Deep Space Propulsion: A Roadmap to Interstellar Flight
 |url=https://archive.org/details/deepspacepropuls00long_553  |url-access=limited  |chapter=Project Daedalus
 |pages=[https://archive.org/details/deepspacepropuls00long_553/page/n212 190]–197
 |publisher=[[Springer Nature|Springer]]
 |isbn=9781461406075
}}

== References ==
{{Reflist}}

==External links==
{{Commons category|Project Daedalus}}
*[http://www.daviddarling.info/encyclopedia/D/Daedalus.html Project Daedalus], The Encyclopedia of Astrobiology Astronomy and Spaceflight
*[http://www.bisbos.com/space_n_daedalus.html Starship Daedalus]
*[https://web.archive.org/web/19991012174630/http://www.geocities.com/TelevisionCity/2049/DAEDALUS.HTM Project Daedalus – Origins]
*[http://www.damninteresting.com/?p=655 The Daedalus Starship]
*[https://web.archive.org/web/20110122073440/http://news.discovery.com/space/project-daedalus-size-comparison-110119.html Renderings of the Daedalus Starship to scale]
*[http://daedalus-zvezdolet.narod.ru/indexeng.html Project Daedalus]
*[https://web.archive.org/web/20130628001133/http://daedalus-zvezdolet.narod.ru/doceng/07eng.doc Project Daedalus: The Propulsion System Part 1; Theoretical considerations and calculations. 2. Review of Advanced Propulsion Systems]
*[http://adsabs.harvard.edu/abs/1978JBIS...31S...5B Title: Project Daedalus. Authors: Bond, A.; Martin, A. R. Publication: Journal of the British Interplanetary Society Supplement, p. S5-S7 Publication Date: 00/1978 Origin: ARI ARI Keywords: Miscellanea, Philosophical Aspects, Extraterrestrial Life Comment: A&AA ID. AAA021.015.025 Bibliographic Code: 1978JBIS...31S...5B]
*[https://www.youtube.com/watch?v=9ym494x_Wi0 British Interplanetary Society: Project Daedalus], video rendering by Hazegrayart
{{Nuclear propulsion}}
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[[Category:Hypothetical spacecraft]]
[[Category:Interstellar travel]]
[[Category:Nuclear spacecraft propulsion]]
[[Category:Barnard's Star]]