Reaching for the stars

As a proposal to build a real-life Starship Enterprise gains attention online, we look at previous engineering studies of how we can go boldly where no-one has gone before

An artist's impression of a spaceship
Marcin Rybarczyk


An ambitious space-lover has captured media attention with a proposal to design and construct first an interplanetary spacecraft and ultimately an interstellar vessel superficially resembling the USS Enterprise from the original incarnation of Star Trek.

The idea is that such an iconic form will attract enough public support to get the funding required to build a spacecraft capable of crossing the final frontier.

Its need to resemble a TV prop may reduce its practicality, however, and such a plan may be, as Spock might say, illogical. So how well does this conceptual outline compare to previous engineering studies of interplanetary and interstellar spacecraft possibilities?

Orion

Starting in 1958 at America’s Los Alamos National Laboratory in New Mexico, the scientists behind Project Orion proposed to power the vehicles used to explore strange new worlds using nuclear pulse propulsion.

Running nuclear reactions within the structure of the spacecraft, similarly to burning fuel in the combustion chamber of a conventional rocket, would produce high temperatures that risked damage to its structure.

Instead, Orion proposed to drop “pulse units” behind the ship at regular intervals. These would each contain a nuclear weapon and a propellant to be blasted back towards the spacecraft, where it would hit a pusher plate, transferring momentum to the vessel via a shock-absorption system.

Models were successfully tested with conventional explosives, but there were concerns about the safety of launching nuclear weapons into space. The 1963 Partial Test Ban Treaty, forbidding the detonation of nuclear weapons except those being conducted underground, effectively killed the project.

Orion was possible to build at the time with the then-available technology. It was calculated that it would reach up to a tenth of the speed of light, and built at different sizes, could be used for hopping around the solar system or even an interstellar mission putting it into orbit around a distant star. It was estimated that a large version of Orion would cost the equivalent of a year’s US gross national product, or $3.67 trillion at 1968 prices.

Daedalus and Icarus

From 1973–8 the British Interplanetary Society (BIS) carried out Project Daedalus, a feasibility study based on the idea of sending an unmanned probe on a flyby of Barnard’s Star six lightyears away, where it would seek out new life and new civilisations after a journey of 50 years.

It was to be a two-stage probe with the first stage accelerating to about 7% of the speed of light until a few years into its journey and the second stage reaching 12% of lightspeed. Propulsion was to be from inertial confinement fusion, in which nuclear fuel is compressed by a laser until it begins a fusion reaction.

Although this is possible with contemporary technology, it would likely mean mining the atmosphere of Jupiter for Helium-3.

BIS and the Tau Zero Foundation began a new five-year mission in 2009, Project Icarus, aimed at updating the original study in light of the past 30 years of technological advancements, but taking into account that many of the original experts in the physics and engineering communities had since retired or died. The two projects are named for their respective characters in Greek mythology: Daedalus the master craftsman who created the Cretan labyrinth where the minotaur was kept, and his son Icarus who attached artificial wings to himself with wax but flew too close to the Sun.

The voyages of the Enterprise

The suggestion for the new Enterprise programme is explicitly intended to carry humans on board, using the saucer-shaped front section to generate artificial gravity by rotating – although the axis around which it would spin is not ideal.

The timescale given is for a first-generation Enterprise to be finished within 20 years. It would use nuclear-electric propulsion that would be capable of reaching Mars within 90 days.

The next generation’s ships, completed every 33 years, would be increasingly advanced until one is built that can maintain a constant acceleration of 1 g all the way to the Sun’s nearest star system, Alpha Centauri. It would require 0.27% of American GDP every year – at around $40 billion in 2012, this is little over half their Department for Education budget.

Ultimately, one proposal such as these will have to be made to work. For as Stephen Hawking and others have suggested, colonising the galaxy is the only way that humankind will live long and prosper.



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