This is the one where streetcar enthusiasts get mighty disappointed its not a new tramway scheme of any sort! In fact Star Tram (sometimes called Space Tram) was a project with the purpose of making it easier to get into space. Rockets are terribly expensive (although Elon Musk’s reusable SpaceX rockets are making space travel a far easier endeavour than ever before.) Star Tram was in fact supposed to be up and running by 2020. As we all know, nothing of the sort has happened – and it remains essentially pie in the sky!
Over the past two centuries people have come up with various ideas that could replace rockets and give easy access to the stars. One of those was that space elevators somehow seemed more conceivable than the Star Tram which is the main thrust of this topic!
Ironically the idea behind Star Tram was that those space elevators were just too technologically difficult and costly to justify. That being the reason why up to this present time no-one had built any space elevators! And voila! Star tram was touted as an easier, cheaper, alternative.
But was it really cheaper & easier to build? Well there’s one fact that stands out and it might come as a surprise – but just like space elevators have not yet been built, it turns out too that nobody has yet built Star Tram!
Georges Melies A Trip to the Moon (1902.) Source: Pinterest
Star Tram was almost without a doubt another of those ‘let’s get to the moon on the cheap’ wheezes. In the past it was simply thought railguns, or huge cannon, would get humans there. Such examples were depicted in Jules Verne’s novels as well as the 1902 film A Trip to the Moon. Thus humans could easily visit the moon if only for the beer – never mind its moon rocks or the wrath of the Selenites!
In fact despite all these promises its not actually cheap which ever way one looks at it. Its not going to be cheap to put beer on the moon let alone a colony of humans! Not until the economics shows us that space travel has become manageable, sustainable and most of all, the costs have been enormously brought down.
‘Greetings fellow moon beings. Those damn earthlings have found a new way to invade our world – a friggin star tram!‘ Source: Pinterest
There’s always a huge logistics in these sort of ventures and because rockets are terribly expensive, the idea of making it cheap to get from Earth’s gravity into the free fall zone is one that’s been relentlessly pursued. Elon Musk is of course making huge headway with his SpaceX project – which surprise, surprise is a modified but indeed clever use of rocket technology. Again SpaceX isn’t exactly a new innovation – the idea of returnable rockets was first proposed decades ago – its just the wheels of technology do sometimes move slowly when putting stuff into practice. What SpaceX has achieved now means anything like Star Tram will never get off the ground.
All space development efforts are hindered by the cost of placing payloads in orbit. Reducing launch costs allows more mass to be placed into orbit for a given budget. Most of the weight (mass) in any rocket is used to launch the fuel and not the payload. Electromagnetic (EM) railguns or mass drivers would avoid that problem. Source: ASCE Library
Essentially Star Tram is a type of electromagnetic railgun – guns or massive cannon being the kind of thing that has been mooted for more than a century to send craft into space. The first notion of such a system was propounded by Jules Verne in 1874 in his book From the Earth to the Moon.
The Space Gun depicted in Verne’s From the Earth to the Moon (1874.) Source: Internet Archive.
As well as a being a space gun, Star Tram is in fact another variation upon the earlier types of hyperloop that existed long before Elon Musk even came up with the idea. Thus Star Tram is well, a space gun combined with a maglev system – and surprise – there’s a ‘tram’ somewhere in this too!
Its often said Star Tram was conceived a year before Musk’s Hyperloop, but research shows it was conceived as early as 2001. Thus in the hyperloop wars we know who came first! If anything Musk’s idea is simply a rediscovery of older technologies – just as Start Tram’s too is.
The big departure between the two however is Star Tram can’t work at the nominal speed of 700mph for the earthbound variation. Star Tram must in fact propel craft fast enough to achieve a sufficient velocity in order to escape earth’s gravity. That unfortunately means it isn’t suitable for people as speed of 20,000 miles per hour will be needed to get the craft into space.
If people were carried in these craft with such speeds at the rate of ascent that is being proposed, they wouldn’t be people by the time they reached space. They would be pulverised!
To address this shortcoming a second generation Star Tram was in fact proposed for a later date – being somewhere around 2030. This however is far more expensive than the initial stage involving just 12 miles of maglev tunnel. The passenger version would require a tube suspended in the sky around 1,500 km long, being much less steeply graded in order to keep those G forces down to an acceptable level.
There’s another substantial problem and that is because its a hyperloop system, it depends on a vacuum too. If a craft was hurled through Star Tram’s tunnels at 20,000mph and there was no vacuum in the system the craft would simply burn up. This is the problem with hyperloop whether its on the ground or in the sky. That vacuum has to be present – and it has to be maintained. In other words no air gets in.
Perhaps the biggest problem of all is Star Tram’s space tunnel has to be open ended for the craft to leave it and enter space. The super-conducting vacuum tube must be sealed to prevent any air entering it but also it needs a portal which could open and shut for an instant to allow the craft to eject into space.
The ‘Star Tram’ flies out of the end of its 12 mile long super conducting vacuum tube. Source: You Tube
However the idea anyone was going to be able to mange to keep a twelve mile long tunnel completely devoid of air (the vacuum tube being the central core of this) and then the far end of it open up – even for just an instant – to allow the craft to escape sounded quite impractical.
The solution proposed is a plasma energy window. Its said this would heat up gas to a viscosity in which air could not pass through. In other words it would act as a door to prevent air coming in but allow craft to leave the super gun. Another reason for having a plasma ‘lid’ at the end of the tunnel was, well, if it didn’t open for some reason at least the spacecraft wouldn’t have something to crash into!
Of course the other thing (as I wonder) is if a craft was being projected through the tube and at some stage the plasma window suffered a failure. Whoosh! Air rushes in like mad. No doubt the craft would get burnt to a cinder. What it means is Star Tram would essentially become a super high speed incinerator!
And we wouldn’t want to have a passenger version of it where a failure of this sort ended up cremating those passengers. When one thinks about this, its mad, bad – especially if it was a transport system that had an extremely fine line between life and death!
The designers of Star Tram would probably not have thought that however. I suppose someone would think of a concept that could work, but even so this ‘plasma window’ is the most technologically difficult part of Star Tram as far as I am concerned. In all honesty I think it would somehow be easier to send a rocket through a barn at the speed of light and still have both its end doors closed simultaneously whilst the rocket was inside!
Example of a maglifter used to propel craft into space.
Star Tram was dreamt up in 2001 by Dr Powell and Dr Maise – following a paper drawn up in 1994 by one of NASA’s scientists, John Makin, on what was called a maglifter. This essentially is a railgun adapted to use maglev technology. The maglev part would be the means by which the craft would be propelled to those huge speeds necessary to reach space. The problem with Makin’s maglifter was it needed lots of land and big mountains for it to work.
Maise and Powell claimed Star Tram would be better than a maglifter because it would release craft much nearer space – which means the energy requirements would not be as great as those for a maglifter.
One might however easily imagine that Star Tram would in fact need loads of energy to get its craft into space. Actually it turns out it would need the full output of a large power station for a mere twenty minutes! Quick everyone! A Star Tram launch’s imminent please do not turn on your lights, fridges or computers for the next half hour or so! No brewing tea or using that shower either!
As we have seen it was also claimed Star Tram would be easier to build than a space elevator. Not only that it would too be less complex than the large hadron collider. What it all meant was once Star Tram had been built – putting a pound of cargo into space would drop in terms of cost from about $4500 down to just $100.
The inventors of Star Tram were Maglev’s designer Dr James Powell (right) and aerospace engineer Dr George Maise.
Dr. James R. Powell is of course the father of the modern maglev train. His designs were copied the world over. The idea of maglev (and hyperloop) is actually quite old (as he himself has acknowledged) having first been invented in the 1900s but largely forgotten. Powell’s designs were first conceived in 1959 as a means of improving on the very limitations of those earlier systems. His solution was to place the magnets on the trains themselves instead of on the track. The complete designs for a high speed maglev railway, designed in conjunction with his colleague Dr. Gordon Danby, were first published in 1966.
In a way Star Tram is like building an extremely long Hyperloop tunnel on earth and then using a huge lattice tether system, causing the remainder of it to soar right up into the sky. The maglev would not only have been for the propulsion of the craft but also to keep the entire structure tightly rigid up there in the upper atmosphere.
In fact the cables themselves would also be superconducted. They would carry loads of power and essentially be magnets flying in the air, keeping the whole structure taut. The image below shows how the Star Tram’s super lightweight structure would have been built.
The tunnel would have been at least twelve miles long – some pretty mighty construction and the feat of getting it to project up towards the heavens – and stay exactly in place – was going to be something of a major achievement! It would take ten years apparently just to build the thing!
Extremely strong cables known as Dyneema would help to stablise the structure. In fact it seems this was chosen because it had already proven its worth in an experiment conducted by Russian students in 2007 – where two satellites were tethered together by a 30km strand of Dyneema.
Conceptual image of a Star Tram base.
The first part of Star Tram would be a base sited at the foot of a mountain somewhere. The launch tunnel would initially be through the base of the mountain itself but then rise beyond this. Ultimately Star Tram would enable space craft to pass through 96% of Earth’s atmosphere, which means from the top end of the ‘tram track’ twelve to fourteen miles up the act of getting into space was easily cinched.
Star Tram’s tunnel leaves the mountain base and rises skywards.
At roughly 2012 costs, the finance needed for the initial scheme for a 18km or twelve mile long tunnel was said to be $20 billion, while the second stage, the passenger one, would cost $67 billion – and that would take 20 years. If they were to start on that now it would be ready around 2040!
Up and up it goes! It might be a simple structure but a lot of land would evidently be needed for it.
Star Tram aspired to use existing technologies to achieve its aims. The problem however is unlike a space elevator which at least uses a single anchor point on earth, Star Tram needs anchors everywhere along its route (as well as tunnelling through mountains for the first part of its route.) The higher it goes the wider the anchor base needs to be. The upper end of the tunnel would reach twelve and half miles (20km) into the sky – roughly twice the altitude normal commercial aircraft travel at.
The only problem really was despite the initial promises on paper, the unprecedented use of these particular technologies within a space context – in other words put to use in ways they had never been used before – never mind the difficulties these technologies alone face on the Earth itself, meant that even though many thought it a commendable attempt at providing an alternative to other means of reaching space, the sheer logistics such as the construction of the entire skyward tunnel system, the plasma window, the land required and the fact it would take years to build was probably Star Tram’s undoing.
In terms of being a passenger transport facility many people scoffed at the notion that one could build a 750 mile long (1200km – tho some say up to 1500km would be needed) tunnel soaring up into the skies. Just think how much anchorage and land that would require as well as the power to keep it all magnetically levitating!
Craft exiting Star Tram’s twelve mile long (18km) super maglev tunnel in the upper atmosphere would then be able to reach space with apparently little effort.
One of the major problems with Star Tram is of course the Kármán line. That’s not a competitor project by the way lol! The Kármán line is in fact very important. Its the point at which it is determined the atmosphere becomes too thin for craft to fly. Star Tram releases its craft 12 to 14 miles up into the skies yet the Kármán line indicates the demarcation between our atmosphere and space itself begins at about 57 to 60 miles about the earth.
However what is important is this varies according to conditions – its not exact. This means there is still a certain amount of air resistance to be had and since no one has yet shot a craft into space using a magnetic railgun (or maglifter or plasma railgun etc) the actual results of doing this are not known. There is the danger a craft could skim the top of the atmosphere instead and return to earth uncontrolled, burning up in the process. The Kármán line (as well as other atmospheric problems) are no problem for a rocket of course – that in a nutshell is why rockets have endured as the main means of getting into space.
To sum up – when one considers the very contexts of this rather grandiose space project, the act of building a Hyperloop transportation system would indeed have been child’s play!
Unsurprisingly not a single bit of Star Tram has ever been built. Its always remained an idea on paper – a rather fanciful idea and its perhaps the kind of stuff best left to science fiction novels.
The above Star Tram images and diagram is from the project’s pages which are found at the Internet Archive.
The Star Tram’s US Patent can be found here.