The Evolution of Space Rockets

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The fundamental principle behind  modern rocketry was understood two  

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and a half millennia ago by the Ancient Greeks.

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But the first proper working rockets, historians  agree, were fireworks in ancient China,  

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during the first century AD. Hollow bamboo tubes,  stuffed with a rudimentary fuel of saltpetre,  

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sulfur and charcoal dust would’ve made for a  cool noisy projectile to show off at parties.

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Before long some dreadful meanie saw the  potential military application. Surviving  

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accounts from the 13th century battle of Kai-Keng  report terrifying ‘arrows of flying fire’,  

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basically rudimentary Song Dynasty rockets,  raining down on the rampaging Mongol hordes.

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In all likelihood these crude missiles  sucked. But they struck sufficient fear  

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into Mongol hearts that the nomadic  horse-folk crafted their own rival  

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rocket weapon. Which is most likely how  the idea eventually made it to Europe.

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By the 17th century, the concept was well enough  understood that the term ‘rocket’ was coined,  

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based on the Italian word ‘roquette’ incidentally,  

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a pointy bit for holding the thread  on an old-school spinning wheel.

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Around the same time, in England,  

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Isaac Newton codified the laws of motion for  the first time. Newton’s third law – every  

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action has an equal and opposite reaction –  neatly sums up how rockets do their thing.

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Back in Asia, in the late 18th century,  

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the kingdom of Mysore in present-day southern  India developed their own rocket weapon,  

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using sturdy iron tubes to launch  projectiles an impressive 2km or so.

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So successful was the Mysorean rocket  program that an Englishman named William  

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Congreve stole the idea and, by the  early 19th century, was cheerfully  

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bombarding the upstart American colonies  with his clone rockets in the war of 1812.

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Rockets’ utility as a weapon of war  faded somewhat after this, as the  

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superior performance and accuracy of guns made  smaller-format weapons more effective in battle.

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Still, these whiz-bang contraptions  had captured the popular imagination.  

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And it wasn’t long before bold visionaries were  positing a very different application for rockets.

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In 1861 a Scottish priest and amateur  astronomer called William Leitch wrote  

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a book called ‘God’s Glory in the Heavens’, in  which he advanced the radical idea that mankind  

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might make a new life out among the stars,  with the help of this exciting technology.

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‘Let us… attempt to escape from the  narrow confines of our globe… and  

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see it from a different point  of view’, eulogized Leitch.

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‘But what vehicle can we avail  ourselves off for our excursion?  

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The only machine we can conceive of would  be one of the principles of the rocket.’

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In that same decade, science fiction writer  Jules Verne published his uncannily prescient  

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novel ‘From the Earth to the Moon’. In the book  – written 100 years before the Apollo missions,  

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by the way – Verne correctly predicted  the cost of a 20th-century space launch,  

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controlled for inflation, and foresaw nifty  details like the fact there’d probably be a  

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three-man crew. He even correctly guessed  it would be launched from Florida.

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One Jules Verne fan in particular set even out  to make art imitate life. Konstantin Tsiolkovsky,  

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a mild-mannered Russian high school maths  teacher published an early iteration of  

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what’s now known as the ‘rocket equation’ in  a 1903 aviation magazine article thrillingly  

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entitled ‘Exploration of Outer  Space with Reaction Machines’.

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The rocket equation, since you ask, sets out  the relationship between rocket speed and mass,  

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and how quickly gas has to exit the propellant  system to achieve lift. One crucial insight from  

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Konstantin’s work is that the relationship between  fuel and speed is exponential. That means it’s  

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non-linear. If you want to double the velocity of  your rocket, simply doubling the fuel won’t do.

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Tsiolkovsky did more than just the math.  

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He vividly articulated a vision of what  future spacecraft might ultimately look like.

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‘Visualize… an elongated metal chamber,  

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the shape of least resistance,’  he wrote, in about 1900 remember.

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‘Equipped with electric light, oxygen  and means of absorbing carbon dioxide,  

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doors and other animal secretions.

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‘At the narrow end of the tube,’ he went on,  

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‘explosives are mixed: this is  where the dense, burning gases…  

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explode outward into space at a tremendous  relative velocity at the… flared end of the tube.

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‘Clearly, under definite conditions, such  a projectile will ascend like a rocket.’

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Konstantin wasn’t alone in this  vision. In the United States,  

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Robert Goddard independently developed  his own version of the rocket equation,  

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inspired by yet another science fiction  writer, HG Wells. In March of 1926  

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Goddard made history launching the first-ever  liquid-fuelled rocket in Auburn, Massachusetts.

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Goddard’s contribution to  rocketry can’t be overstated,  

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developing the technology behind no fewer than  214 patents. In his experiments he concluded,  

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among other insights, that combustion  should happen in small chambers,  

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separate from primary fuel. Which should, he  reckoned, be held in two separate tanks – one  

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containing fuel, typically alcohol based  on his early trials, and an oxidizer.

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He also realized space-bound rockets would  need to be arranged in stages. As early as  

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the 16th-century German firework maker Johann  Schmidlap proposed a "step rocket”, in which a  

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large rocket advances as far as it can, burning  all its fuel, before launching its own second  

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projectile to go even higher – the principle  behind all modern space missions. But Goddard  

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made it work for real. He also ascertained that  solid rocket fuel burns too unevenly for accurate  

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control, so liquid was better. He also devised  a clever gyroscope to keep things on course,  

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parachutes to bring things safely back to  earth, and the use of the de Laval nozzle.

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The de Laval nozzle, since you ask,  

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accelerates the flow of gases through a  section of tube by narrowing it into an  

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asymmetric yet finely calibrated hourglass  shape. That might not sound like much, but  

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alchemising heat energy into kinetic force creates  an additional lift without any extral combustion.

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In 1920 Professor Goddard was so famous for his  dream of getting a rocket into space the New York  

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Times published a mocking editorial, suggesting  he didn’t properly grasp Newton’s Third Law.

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He ‘…does not know the relation of  action to reaction,’ thundered the paper.  

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‘Or of the need to have something better  than a vacuum against which to react.

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‘He seems to lack the knowledge  ladled out daily in high schools’.

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The Times subsequently issued an apology  to Goddard, 14 years after his death,  

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and about a month before the moon landings.

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Another early giant of the field – one of  many scattered across tinkering workshops and  

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amateur societies around the field – was one  Hermann Oberth. Born in present-day Romania,  

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Oberth spent much of his life in Germany.  Rather than being inspired by science fiction  

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like Konstantin in Russia and Goddard in the  States, Oberth actually inspired science fiction,  

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working as a scientific consultant on  legendary film director Fritz Lang’s  

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1929 film ‘the Woman in the Moon’. Clearly already  a big name in rocketry, that same year he wrote a  

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book called "Ways to Spaceflight" and took on as  an apprentice a young man named Werner von Braun.

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Von Braun took Oberth’s teachings  and went on to develop one of the  

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most important rockets in history – the  German Aggregat-4, better known as the V2.

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The V2, used to devastating effect against the  allies in World War 2, was the world’s first  

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ballistic missile. Stubby by today’s standards at  just 14 metres high, it somehow managed phenomenal  

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thrust burning liquid oxygen and alcohol at a  rate of around a ton every seven seconds. It was  

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the first man-made object to break the sound  barrier, and the first to reach outer space.

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Still, it couldn’t win the war for Germany.  After the conflict the V2’s senior engineers  

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were lured over to either the US or Soviet Russia,  to progress their own nascent rocket programmes.

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Werner Von Braun always preferred the  idea of making rockets for space travel,  

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instead of killing civilians.

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And his know-how helped drive postwar  rocket development in the United States,  

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where NACA, the National Advisory Committee  for Aeronautics, a forerunner of NASA,  

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oversaw progress on rocket features from basic  structural components, mechanical elements  

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like pump valves, engine cooling systems,  clever new direction controls and more.

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‘Blunt Body Theory’, from which it  is understood blunt shapes are better  

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at surviving burnup on re-entry than more  aerodynamic bodies, was developed by NACA.

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Experiments in staged rocketry were  conducted on captured German V2 rockets  

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upgraded with a smaller rocket as  payload to be launched at peak altitude.

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Advances in the development of more energetic  and stable solid fuels found a use in ICBM,  

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or Intercontinental Ballistic Missiles,  which in the febrile Cold War climate  

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needed to be ready to fire at a moment’s notice.

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The Russians, for their part, weren’t  hanging around. Their own ex-German recruit,  

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Helmut Gröttrup, helped Soviet chief  designer Sergei Korolev develop the R-1.  

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This in turn led to the R-7, a two-stage  ballistic missile capable of traveling  

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8,000 km, that became the workhorse of the  Russian space program for half a century.

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It won some significant early battles  in the so-called race for space when,  

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on October 4, 1957, the R-7 hurled the first-ever  

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man-made satellite Sputnik into orbit. A  month later, Laika the dog followed suit.

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In the US President Eisenhower was  incensed to have been beaten to the punch,  

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and briskly signed the National  Aeronautics and Space Act in July 1958.

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Despite rapidly developing the Mercury Redstone  booster, again based on the basic V-2 outline,  

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Russia again made the running by  launching the first human into space,  

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Yuri Gagarin, on a modified version  of the classic Soviet R-7 rocket.

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The 1960s was boom time for rocket engineers,  with President Kennedy promising a man on  

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the moon by the end of the decade. Humongous  injections of state cash drove the evolution  

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of rocketry at this point, and Werner Von  Braun’s ultimate vision was realised in  

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the shape of the three-stage Saturn V that in  1969 carried mankind all the way to the moon.

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The Russians, for their part, tried to  catch up. But with budget issues and the  

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death of their whizkid Sergei Korolev,  it never really happened for them.

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Meanwhile an imperious and cash-rich USA  developed the Space Shuttle, a visionary  

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re-usable craft that distinctively relied  upon two solid-fuel boosters to get to orbit.

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The first shuttle was named Enterprise – clearly  sci-fi influencing real science yet again – and  

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the idea may well have caught on, had it not  been a wildly expensive means of getting to and  

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from space. Not to mention the sad fallout from  the Challenger disaster of 1986, which led to a  

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radical redesigns of those solid-fuel boosters  we mentioned, and the Columbia tragedy of 2003.

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To be clear, it isn’t just the Russians and  Americans sending rockets into space. Inspired by  

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Soviet successes from Sputnik onwards, the Chinese  developed their own late 50s rocket programme,  

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which continues to this day with the Long March  programme regularly launching from the tropical  

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island of Hainan. The deep-pocketed superpower  is highly secretive about the programme,  

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which earlier this year had a hair-raising  moment and attracted international condemnation  

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when an out of control rocket came hurtling  down to earth, luckily without hurting anybody.

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Still, most of the important ground-breaking  work has come out of America. In 2004  

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president George W Bush announced the  retirement of the Shuttle programme  

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but the introduction of two new lunar rockets,  the Ares I and Ares V. Both two-stage rockets,  

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the idea was once again to get to orbit on  a first stage using solid fuel boosters,  

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then switching to liquid fuelled Rocketdyne J-2X  engines to make it to the moon and ideally beyond.

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However in 2010, citing the  global financial crisis,  

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Barack Obama cancelled the Ares programm.  Still, in the same move they greenlit the SLS,  

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or Space Launch System, which looks set to put the  first woman on the moon in 2024. Thanks, Obama.

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If the history of rockets can be summed up  as pretty fireworks, which became weapons,  

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became tools of geopolitical  posturing in the late 20th century,  

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these days it’s all about money.  Not necessarily in a bad way.

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The radical innovations happening under Elon  Musk’s watch at SpaceX – not least reusable,  

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landable Falcon 9s – are driven by the  profit motive. To get payloads – and  

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indeed, now, astronauts – to orbit  in a safe and cost-effective manner.

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This in turn is driving every  greater speed of design iteration,  

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like the progression from the  throttlable Merlin to the Raptor engines.

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The latter of which runs on Meth-Ox, a  methane-based fuel because it burns clean.  

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This is obviously great from  a re-usability perspective,  

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meaning engines require less maintenance between  flights. But also because the Starships currently  

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in development in south Texas should be able  to extract their own methane as a fuel source  

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on mars, a concept almost beyond  the dreams of science fiction.

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If Musk gets his way, the starships will  not only be ferrying Mankind to mars,  

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but will also be carrying us from point to point  here on earth faster than any conventional jet.

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And what does the future hold? New Zealand  startup Rocket Lab is developing a Rutherford  

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Engine that incorporates 3D printed  elements with an electric pump-fed engine,  

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and should unveil its own  heavy-lift Neutron rocket in 2024.

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Going forwards, Nuclear fusion reactors  may even provide an even more potent  

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fuel source without needing combustion at all.

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Now private enterprise is fully  engaged, we human beings aren’t  

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flinging rockets at each other (all  that much) and space is cool again,  

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one thing we can be sure of is that  the future for rockets is looking up.

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What do you think? Does mankind’s love  of sci-fi, or its warmongering instincts,  

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most deserve credit for the revolution  in rocketry? Let us know in the comments,  

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