Posts Tagged ‘JBIS’

JBIS Article on the Skylon British Spaceplane

October 9, 2018

In my last article, I discussed the forthcoming edition of the Beeb’s long-running space and astronomy programme, the Sky at Night, on the history of Britain in space. The programme will be presented by Tim Peake, and the blurb about it this week’s Radio Times looks forward to the opening of Britain’s first spaceport in Scotland within the next few years. The Radio Times doesn’t mention it, but recent newspaper articles have stated that such a spaceport will be built sometime in the very near future for launching the Skylon spaceplane. This is an unmanned vehicle, which has been developed as the successor to the 1980s HOTOL spaceplane.

Two of the scientists and engineers involved in the project, Richard Varvill and Alan Bond, published an article describing the plane in the Journal of the British Interplanetary Society, Vol. 57, no. 1/ 2, for January/February 2004. The JBIS is the technical magazine of the British Interplanetary Society, founded in the 1930s to encourage British research into rocketry and space travel. The article runs from p.22 to p.32. The article itself is too long to reproduce, but its abstract runs as follows:

SKYLON is a single stage to orbit (SSTO) winged spaceplane designed to give routine low cost access to space. At a gross takeoff weight of 275 tonnes of which 2202 tonnes is propellant the vehicle is capable of placing 12 tonnes into an equatorial low Earth orbit. The vehicle configuration consists of a slender fuselage containing the propellant tankage and payload bay with delta wings located midway along the fuselage carrying the SABRE engines in axisymmetric nacelles on the wingtips. The vehicle takes off and lands horizontally on its own undercarriage. The fuselage is constructed as a multilayer structure consisting of aeroshell, insulation, structure and tankage. SKYLON employs extant or near term materials technology in order to minimize development cost and risk. The SABRE engines have a dual mode capability. In rocket mode the engine operates as a closed cycle liquid oxygen/liquid hydrogen high specific impulse rocket engine. In airbreathing mode (from takeoff to Mach 5) the liquid oxygen flow is replaced by atmospheric air, increasing the installed specific impulse 3-6 fold. The airflow is drawn into the engine via a 2 shock axisymmetric intake and cooled to cryogenic temperatures prior to compression. The hydrogen fuel flow acts as a heat sink for the closed cycle helium loop before entering the main combustion chamber. (p. 22).

Schematic of the SKYLON spaceplane in the above article.

I’m delighted that the spaceplane is now set to enter service and look forward to the opening of the new spaceport in Scotland.


Real Warp Physics: Travelling to the Pleiades in a Hyperspace with Imaginary Time in 1.3 Years

June 20, 2017

Now for something a little more optimistic. Don’t worry – I’ll get back to bashing the Tories and their vile policies shortly.

Looking through a few back copies of Journal of the British Interplanetary Society, I found a paper by a Japanese physicist, Yoshinari Minami, ‘Travelling to the Stars: Possibilities Given by a Spacetime Featuring Imaginary Time’ in JBIS vol. 56, no. 5/6, May/June 2003, pp. 205-211. The possibility of Faster Than Light travel is taken seriously by a number of physicists, engineers and space scientists, and a number of papers on the possibility of using warp drive or other advanced systems to travel to the stars have been published since Marcel Alcubierre published his paper showing that warp drive was possible, if only in theory, in the 1990s. Incidentally, one of Alcubierre’s names using the Spanish system was ‘Moya’, which was also the name of the living space ship in the SF TV series, Farscape.

In the article, Minami discusses the physics of hyperspace, using some seriously difficult maths to prove that it is in theory possible to travel to the Pleiades, otherwise known as the Seven Sisters, a star cluster 410 light years away in 1.3 Earth years. Without some form of FTL drive a round trip to the Pleiades in a spacecraft travelling at 0.99999 per cent of the speed of light would take 820 years, although due to time dilation the crew would only experience the journey as 3.6 years long.

Minami acknowledges that imaginary time is a difficult concept, and gives some examples of how contemporary scientists are nevertheless incorporating it into their theories and experiments. For example, Stephen Hawking has used imaginary time as part of his attempt to unite relativity and quantum physics. In real time, the universe has a beginning and an end in singularities in which current physics breaks down. However, no such boundaries exist in imaginary time, and so imaginary time may be far more basic as a fundamental property of the cosmos.

He also discusses the way quantum tunnelling is utilised in a number of electronics components. These are the tunnel diode, the tunnel transistor, the tunnel diode charge transformer logic and other devices. Quantum tunnelling is the phenomenon in which a sub-atomic particle can travel slightly faster than light if it has imaginary momentum.

This is seriously mind-blowing stuff. I can remember the excitement back in the 1990s or perhaps the early part of this century, when a team of physicists showed it was possible to use quantum tunnelling to send information slightly faster than the speed of light, something which was previously thought impossible. For SF fans, this raises the possibility that one day Faster Than Light communication devices – the ansibles of Ursula le Guin and the Dirac Telephone of James Blish, could become a reality.

The paper then discusses the possibility of using wormholes or cosmological theories, which posit that the universe has extra dimensions, such as Kaluza-Klein Theory, Supergravity, Superstrings, M theory and D-brane theory to enter hyperspace. Minami states that one form of wormhole – the Euclidean – is considered to include imaginary time in their topology. However, using such a wormhole would be extremely difficult, as they’re smaller than an attempt, suffer fluctuations and the destination and way back is ultimately unknown.

He therefore does not make any detailed suggestion how a future spacecraft could enter hyperspace. But if a spaceship was able to enter hyperspace after accelerating to with a infinitesimal fraction of the speed of light, a flight which lasted for 100 hours in hyperspace would appear to last only 70 hours to an observer on Earth.

He then considers a mission in which a spaceship leaves Earth at a tenth or a fifth the speed of light. After escaping from the solar system, the ship then accelerates to near-light speed. Such a spacecraft would be able to reach the Pleiades in 1.8 years ship time, which 1.3 years have passed to the scientists waiting back on Earth. This method of transport would not violate the causality principle, and could be used at all times and everywhere back in real space.

I don’t pretend for a single moment to be able to follow the maths. All I can say is that, if a hyperspace with an imaginary time exists, then, as Star Trek’s Captain Jean-Luc Picard would say, ‘Make it so!’