Showing posts with label carbyne. Show all posts
Showing posts with label carbyne. Show all posts

Tuesday 23 April 2019

Lift to the stars: sci-fi hype and the space elevator

As an avid science-fiction reader during my childhood, one of the most outstanding extrapolations for future technology was that of the space elevator. As popularised in Arthur C. Clarke's 1979 novel, The Fountains of Paradise, the elevator was described as a twenty-second century project. I've previously written about near-future plans for private sector spaceflight, but the elevator would be a paradigm shift in space transportation: a way of potentially reaching as far as geosynchronous orbit without the need for rocket engines.

Despite the novelty of the idea: a tower stretching from Earth - or indeed any planet's surface - to geosynchronous orbit and beyond; the first description dates back to 1895 and writings of the Russian theoretical astronautics pioneer Konstantin Tsiolkovsky. Since the dawn of the Space Age engineers and designers in various nations have either reinvented the elevator from scratch or elaborated on Tsiolkovsky's idea.

There have of course been remarkable technological developments over the intervening period, with carbyne, carbon nanotubes, tubular carbon 60 and graphene seen as potential materials for the elevator, but we are still a long way from being able to build a full-size structure. Indeed, there are now known to be many more impediments to the space elevator than first thought, including a man-made issue that didn't exist at the end of the nineteenth century. Despite this, there seems to be a remarkable number of recent stories about elevator-related experiments and the near-future feasibility of such a project.

An objective look at practical - as opposed to theoretical - studies show that results to date have been decidedly underwhelming. The Space Shuttle programme started tethered satellite tests in 1992. After an initial failure (the first test achieved a distance of a mere 256 metres), a follow up six years later built a tether that was a rather more impressive twenty kilometres long. Then last year the Japanese STARS-me experiment tested a miniature climber component in orbit, albeit at a miniscule distance of nine metres. Bearing in mind that a real tower would be over 35,000 kilometres long, it cannot be argued that the technology is almost available for a full-scale elevator.

This hasn't prevented continuous research by the International Space Elevator Consortium (ISEC), which was formed in 2008 to promote the concept and the technology behind it. It's only to be expected that fans of the space elevator would be enthusiastic, but to my mind their assessment that we are 'tech ready' for its development seems to be optimistic to the point of incredulity.

A contrasting view is that of Google X's researchers, who mothballed their space elevator work in 2014 on the grounds that the requisite technology will not be available for decades to come. While the theoretical strength of carbon nanotubes meets the requirements, the total of cable manufactured to date is seventy centimetres, showing the difficulties in achieving mass production. A key stopping point apparently involves catalyst activity probability; until that problem is resolved, a space elevator less than one metre in length isn't going to convince me, at least.

What is surprising then is that in 2014, the Japanese Obayashi Corporation published a detailed concept that specified a twenty-year construction period starting in 2030. Not to be outdone, the China Academy of Launch Vehicle Technology released news in 2017 of a plan to actually build an elevator by 2045, using a new carbon nanotube fibre. Just how realistic is this, when so little of the massive undertaking has been prototyped beyond the most basic of levels?

The overall budget is estimated to be around US$90 billion, which suggests an international collaboration in order to offset the many years before the completed structure turns a profit. In addition to the materials issue, there are various other problems yet to be resolved. Chief among these are finding a suitable equatorial location (an ocean-based anchor has been suggested), capturing an asteroid for use as a counterweight, dampening vibrational harmonics, removing space junk, micrometeoroid impact protection and shielding passengers from the Van Allen radiation belts. Clearly, just developing the construction material is only one small element of the ultimate effort required.

Despite all these issues, general audience journalism regarding the space elevator - and therefore the resulting public perception - appears as optimistic as the Chinese announcement. How much these two feedback on each other is difficult to ascertain, but there certainly seems to be a case of running before learning to walk. It's strange that China made the claim, bearing in mind how many other rather important things the nation's scientists should be concentrating on, such as environmental degradation and pollution.

Could it be that China's STEM community have fallen for the widespread hype rather than prosaic reality? It's difficult to say how this could be so, considering their sophisticated internet firewall that blocks much of the outside world's content. Clearly though, the world wide web is full of science and technology stories that consist of parrot fashion copying, little or no analysis and click bait-driven headlines.

A balanced, in-depth synthesis of the relevant research is often a secondary consideration. The evolutionary biologist Stephen Jay Gould once labelled the negative impact of such lazy journalism as "authorial passivity before secondary sources." In this particular case, the public impression of what is achievable in the next few decades seems closer to Hollywood science fiction than scientific fact.

Of course, the irony is that even the more STEM-minded section of the public is unlikely to read the original technical articles in a professional journal. Instead, we are reliant on general readership material and the danger inherent in its immensely variable quality. As far as the space elevator goes (currently, about seventy centimetres), there are far more pressing concerns requiring engineering expertise; US$90 billion could, for example, fund projects to improve quality of life in the developing world.

That's not to say that I believe China will construct a space elevator during this century, or that the budget could be found anywhere else, either. But there are times when there's just too much hype and nonsense surrounding science and not enough fact. It's easy enough to make real-world science appear dull next to the likes of Star Trek, but now more than ever we need the public to trust and support STEM if we are to mitigate climate change and all the other environmental concerns.

As for the space elevator itself, let's return to Arthur C. Clarke. Once asked when he thought humanity could build one, he replied: "Probably about fifty years after everybody quits laughing." Unfortunately, bad STEM journalism seems to have joined conservatism as a negative influence in the struggle to promote science to non-scientists. And that's no laughing matter.

Tuesday 13 February 2018

Back to nature: why saving other species could save mankind

Humanity has come a long way from reliance on biologically-derived materials such as wood, bone, antler and fur. Yet this doesn't mean that organic materials have been replaced or many respects surpassed by wholly artificial ones. There are of course new carbon-based materials such as 3D graphene and carbyne that may prove to be the 'ultimate' materials when it comes to properties such as strength, but the history of the past century has shown how natural substances can inspire research too.

Perhaps the most obvious example of this is the hook and loop fastener best known by the trademark Velcro, which is essentially a copy of the burr design on Arctium (burdock) plants. Considering that taxonomists disagree wildly on the global totals of current plant, animal and fungi species - many claiming that less than 20% have been scientifically classified - it seems apparent that nature has plenty more surprises up her sleeve.

Spider silk has long been recognised as an incredibly strong material for its weight, with that generated by many species being up to five times the strength of the equivalent amount of steel. The silk produced by the Madagascan Darwin's bark spider (Caerostris darwini) is ten times stronger than Kevlar, suggesting that bullet-proof clothing manufacturers could do well by investigating it. However, a discovery by an engineering team at Portsmouth University in the UK makes even this seem humdrum: the teeth of limpets are potentially so strong - thanks to a mineral called goethite - that artificial versions of them could be used in high-performance situations, even aircraft components.

In addition to their use in construction, natural substances may prove useful in the development of new pharmaceuticals. I've previously discussed animal defence mechanisms such as that of the bombardier beetle and how small, barely noticed critters such as the peripatus deserve far more investigation. Of course the problem has been that size and aesthetics directly correlate with public attention and newsworthiness, meaning that the likes of the giant panda are used as poster species despite offering little in the way of practical advance for science and technology.

I'm not of course suggesting that species should be judged on the merits of their usefulness to humanity, but that we could probably gain a lot of practical usage from much greater study of the less well known flora and fauna still 'out there'. The resilience of tardigrades is becoming fairly well known, but there are no doubt other seemingly insignificant species with even more astonishing properties. Hydra for example are small, tentacled animals that live in fresh water; thanks to being composed mostly of stem cells they appear to have life cycles that just keep going. There also been limited research on the 'immortal' jellyfish Turritopsis dohrnii; this is surprising, given that the advances in gene splicing technology such as CRISPR-Cas9 and TALEN might lead to important medical breakthroughs, not just glow-in-the-dark pets.

In addition, the race to generate new antibiotics to replace those ineffective against 'superbugs' would suggest any short-cuts that can be taken should be taken. I remember watching a 2006 British murder mystery programme in which people were killed during a hunt for rare South American seeds containing anti-malarial properties. This may be pure fiction, but considering that artemisinin-resistant 'supermalaria' is now on the horizon, the script was somewhat prescient.

The idea behind all this is simple: delving into an existing complex chemical compound is far easier than trying to generate a purely synthetic one from scratch. This is why it is important to conserve small and insignificant species, not just the pandas, elephants and rhinos. Who's to say that a breakthrough medicine or construction material isn't already in existence, just hiding around the corner (or rather, in the genome) of some overlooked species of animal, plant or fungi?

With superbug-beating pharmaceuticals and climate mitigation technology a priority, we're shooting ourselves in the foot if we let an increasing number of unconsidered species became extinct. As I discussed last month all sorts of organisms are now in serious trouble from global amphibian populations via North American snakes and bats to the mighty kauri trees of New Zealand. Just saving a few specimens of doomed species in freezers or formalin is unlikely to be enough: shouldn't we endeavour to minimise species loss for many reasons; and if we must have an economic motive, what about their potential benefit to mankind? Not for nothing has nature been deemed 'the master crafts(person) of molecules' and we lose volumes in that library at own expense.