Innokenti asks

Weapons in space. I imagine Sci-Fi shows lie to us lots about the sort of stuff that might be effective in a space-battle. For example as I understand nukes would only be of minimal use out there in space.

What are the most efficient weapons for space-battles though? (Assuming largely human technology of near-future imagination rather than magic alien energy shields and stuff.)

Yes. Yes they do lie to you, in the same way that spaceships don’t actually handle like jet fighters in a vacuum what with having no atmosphere to react against. Space combat, if it ever happened, would likely be ridiculously crude and nasty thanks to the Newtonian nature of space. Things are whizzing around very quickly making them hard to target, but at the same time you can accelerate a projectile up to unheard-of velocities thanks to not having to worry about any of that pesky atmospheric drag. Most current theories about space weapons involve adaptations of current Earth-based weapons systems, but they all carry certain advantages and disadvantages inherent in their design.

Real examples of weapons in space.

There is one! Back when the Cold War was in full swing the Soviets decided it would be a good idea to mount a 23mm anti-aircraft cannon on Salyut-3 (a space station) to defend against “US space-based interceptors”, with integrated rocket boosters to cancel out the recoil thrust that might have resulted in de-orbiting the space station. It wasn’t the most elegant of space weapons since it could not track a target independently, instead requiring the entire space station to be oriented towards the target. There are conflicting reports on whether it was ever used; it was certainly never used while there were cosmonauts on board due to the inherent risk of firing high-explosive cannon shells via an untested system in a vacuum, but it may have been test-fired after the cosmonauts left. Barring any of the top-secret weapons programs so enamoured of Hollywood, this remains (to my knowledge) the only actual example of the weaponization of space.

Anyway, you wanted to know about current or near-future weapons systems that might be adapted for space use. This means we’re talking bullets, missiles or (mirroring current developments in the way high-technology nations fight wars) drones of some kind. However, thanks to the ranges at which a space engagement would be fought and the speeds at which spaceships travel, there are some quirks involved with each one.

1) Conventional high explosives are now pretty much useless.

High explosives are “high” because they have what is called a high brisance; essentially the rate of expansion of the explosive gas. If this is very high it’ll compress the atmosphere around it and force it outwards in a highly destructive shockwave that does most of the damage – it’s like being hit by a solid wall of air moving at the speed of sound, which is easily enough to knock down buildings and rip limbs from their sockets. But in space, of course, there is no atmosphere; no medium through which the explosive can transmit its destructive force. All it’ll have left will be the force of the explosive gas itself which, while considerable, will diminish considerably over distance thanks to the inverse square law. This means that most conventional explosives – including nukes – are much less effective in space. There are two ways you could adapt an explosive to make it more useful:

Use it as the explosive force for some kind of flak or fragmentation shell. This at least alleviates the problem of having your destructive force dispersing uniformly into an expanding sphere by transferring it to discrete fragments or projectiles which concentrate the kinetic energy of the explosion. Unfortunately I doubt you’d get a whole lot of velocity out of a high explosive burst, so the fragments themselves still wouldn’t pack that much of a punch. Much like real-world flak this would be useful for area denial and little else.

Shape the explosion so that it is focused in one direction. Shaped charges are all the rage these days, and if you got your shaped charge in contact with an enemy spaceship there’s no reason why it wouldn’t do just as much damage to it as a High Explosive Anti-Tank (HEAT) shell would to an Iraqi T-55. This too has a drawback, though, and it’s that if you have to score a near-hit with a shaped charge to do any damage, you may as well take out the explosive and make your shell a solid lump of metal instead. This brings us to…

2) Bullets are now absurdly deadly.

Or at least, their lethal potential is now drastically increased. A regular gun you could buy in a shop in the US would work just fine in the vacuum of space – the primer and cordite explosive used to accelerate the bullet come with their own oxidiser, so lack of oxygen would not be a problem. The bullet would also leave the barrel slightly faster too what with it not having to force its way through any atmospheric gas. However, a regular gun is not going to be significantly more lethal in space than on Earth. If whatever you’re shooting at is armoured in any way then the bullets will still bounce off. Bullets do most of their damage via kinetic energy, or

Which is about the zillionth time I’ve used this equation. There’s a maximum velocity achieveable by gunpowder weapons (details of why are in my post on light gas guns), and so there’s a hard ceiling on the potential kinetic energy of a normal bullet. We’re not too concerned about this on Earth because honestly the guns we have kill people pretty good, but if you took even the anti-aircraft cannon they mounted on Salyut and tried to kill a spaceship with it you’d run into a big problem: namely that spaceships move really fast. We’re talking relative velocities of at least several kilometres per second. Unless it’s coming towards you, the spaceship will be able to simply outrun your bullets, and even if they were they would be an incredible pain in the ass to target. Consider that Goalkeeper/Phalanx CIWS systems have trouble shooting down incoming anti-ship missiles — which are moving a lot slower than our hypothetical spaceship — and you have some idea of the scale of the problem.

The “good” news is that even future spaceships will likely not mount a huge amount of armour plating without some kind of revolutionary new engine system that renders all that extra mass irrelevant. If you scored a hit with even a simple kinetic slug you’d do an awful lot of damage; micrometeoroid impacts are a big problem for orbiting satellites, and those are just tiny chunks of rock a few millimetres in diameter. The trick, both to ensure a hit and to ensure that hit scores a kill, is to make your projectile go as fast as possible. This is something that gunpowder weapons simply aren’t capable of so you’d need to chuck out that system and replace it with a functioning railgun system or something, but it’s certainly theoretically possible. Even then, though, at the engagement ranges spaceship battles are likely to take place at (thousands of kilometres at the very least) it would be trivial for your target to take evasive action if they saw you coming. So you either have to blanket space with a lot of projectiles, or else make your projectiles guided in some way.

3) Missiles are a middle-of-the-road approach.

When I talk about space missiles, I’m not talking about what you’d normally conceive of as a missile, with the rocket booster that constantly burns to provide thrust. This would be redundant and silly on a space missile, since if you had the tech to accelerate a kinetic projectile up to several km/s as in 2) it’d be far easier to launch the missile that way rather than relying on chemical fuel rockets. No, a space missile would consist of a very sparse maneuvering system for making course corrections along with a guidance package to make sure it hits the target. It’d have more in common with the ubiquitous idea of the “killsat” – a satellite designed to take out other satellites by colliding with them – than it would a conventional missile. The advantage of this design would be that your chances of hitting the target increase exponentially once you make the projectile guided. The disadvantages would be exactly the same as those of regular missiles: they would need some sort of active sensor system in order to track their target that the target would see coming several thousand kilometres away.

4) Manned space fighters are not going to happen.

Sorry, but there aren’t going to be any Starbucks or Apollos flying around in the space battles of the future. While it might seem like a neat idea to get in an X-Wing and go gallivanting around the galaxy, if you actually put a human in a military space vehicle all you would be doing is introducing a massive weak point and drain on the resources of the spacecraft. Humans need food, water, oxygen, heat, and all those other little amenities we take for granted here on Earth, and any manoeuvring the spacecraft did would be limited by the requirement to not kill the people inside through excessive G-forces. All this, and a human wouldn’t actually add very much to the spacecraft. Like jet airliners modern spacecraft are all flown by computers these days anyway (yes, even the Space Shuttle) so there’s no real need to have humans on board.

5) Drone fighters almost certainly are.

That thing in the picture? That’s a Predator drone, one of many which can be found flying over Afghanistan and Iraq looking for “terrorists”. At first Predators were simple reconnaissance craft that were supposed to guide vehicles driven/piloted by actual live humans to their targets, but eventually some bright spark came up with the idea of arming Predator drones with Hellfire missiles. Now the Predators hunt all on their own, with the only human intervention coming in the form of a control signal from a trailer park near Las Vegas, Nevada.

That, if anything, is the sort of weapon that is going to be fighting a space war; an autonomous computer-controlled spacecraft capable of deploying subsidiary weapons systems on its own say-so¹. Solving the problem of true autonomy is a significant hurdle, but if an AI can be developed which is capable of running a spacecraft on its own with very little intervention from Earth beyond broad strategic directions then drone spacecraft would be by far the best option for fighting in space. They can move faster, react quicker and are actually capable of targeting other spacecraft moving at several km/s with a fair chance of scoring a hit. A drone fighter wouldn’t look like a Predator; instead, it’d resemble a militarised version of a space probe since aerodynamics and armour would be completely irrelevant in space. At its most basic level the drone would simply attempt to collide with an enemy spacecraft, much like the guided “missile” concept above. There’s more potential in it than that, though; you’d need to launch the drone from somewhere and that somewhere would probably be a larger drone mothership which would be the actual military asset, the smaller drones fulfilling a role similar to cruise missiles on Earth.

Wars in space would therefore take place with a minimum of human intervention. You would need the long-term strategic planning capacity of the human brain, but past that everything would be in the hands of the machines. It would be a war fought by remote control, where the combatants and casualties have no first and last names but merely a make and model. We’re moving in this direction in our enthusiastic pursuit of atmospheric combat at the bottom of a gravity well, so I see no reason why we wouldn’t apply the same technology and the same concepts to space.

Of course, this assumes that the human race would ever get around to fighting a space war. Right now we can’t even be bothered to go to the Moon; interplanetary war seems at least a couple of centuries beyond us. By then technology will have likely changed beyond all recognition, so all of what I just wrote was complete bollocks. I just hope it was entertaining bollocks, is all.

1. Predator drones don’t quite have this level of autonomy because it makes people a bit nervous, but they could if the US military didn’t have a problem with a machine making a wrong call and incinerating a bunch of civilians with an erroneously-targeted Hellfire missile. Oddly enough it’s A-OK when human pilots do this, as if having your bloody violent death dispensed by an actual person is somehow a more palatable idea for Western civilization to swallow.

The post In The Grim Darkness Of The Far Future There Is Only War. appeared first on The Scientific Gamer.

Rockets suck. This is a thing that we have established here; they’re terrifically awful ways of getting into space that are only used because nobody has really come up with anything better. There’s all sorts of ideas for wacky drive systems once your spacecraft is actually in space – ion drives, solar sails, Bussard ramjets – but these all sidestep the real problem facing future space travel, which is that you have to get out of the Earth’s gravity well first. This is not easy; even though the Earth is pretty small for a planet it’s still the heaviest of the four terrestrials and has what is to us a very hefty gravitational pull.

In order to exit Earth’s gravity well, an object being launched on a ballistic trajectory from the Earth’s surface must attain escape velocity. Escape velocity is calculated by

where G is the gravitational constant, M is the mass of the Earth and R is the radius of the Earth. For “ballistic” you can read “in freefall” – i.e. an object moving without any other forces acting on it. Rockets do have external forces acting on them thanks to their propulsion systems, so a rocket doesn’t necessarily have to reach escape velocity of 11.2 kilometres per second in order to escape the Earth’s gravity so long as it’s under constant power. However, the amount of energy it will have to expend will be the same as this hypothetical ballistic object, and that can be worked out by using the equation for kinetic energy.

where m is the mass of the spacecraft. With Earth’s escape velocity being 11.2 km s^-1, we can rearrange this equation to find out how much energy per kilo of mass a launch vehicle will need to have to escape Earth’s gravitational pull, and this turns out to be about 63 megajoules per kilogram. I always get a little lost when trying to visualise what a joule is in everyday terms, but Wikipedia tells me that 63 megajoules is roughly the amount of energy you’d release if you detonated fifteen kilograms of TNT. So for a crude method of visualising this, go and look at a picture of a rocket. Imagine a pile of TNT fifteen times as big. Blowing up this pile of TNT would release the same amount of energy as would be needed to get that rocket out of the Earth’s gravity well.

(One significant caveat here: rockets going into orbit don’t need to expend this much energy. They just need to go fast enough that they never hit the ground.)

This amount of energy is fixed. There is no way of getting around it; if you want to go into space, you have to expend at least 63 MJ per kilo of spacecraft mass and this energy has to come from somewhere. For rockets, it comes from rocket fuel; unfortunately rocket fuel increases the mass of the rocket, which requires more rocket fuel, which increases the mass of the- actually I think I’ve done this already, haven’t I. Anyway, rockets suck, but we still use them because the alternative solutions are, to put it mildly, just a little bit far-fetched.

Solution 1: Build better rockets.

Ahaha. Ahahaha. Ahaha. No. Rocket science isn’t necessarily all that complicated – I can understand it, after all – and one of the things that struck me when I was studying space science in the second year of my undergraduate degree was that rockets are a dead end. Well, that’s a bit harsh. Better to say that they’ve been refined as much as they can be.

Two things affect the amount of thrust you can get out of a rocket: the expansion velocity of the exhaust gas you’re creating by burning the fuel, and the size of the rocket nozzle. Rapidly expanding rocket fuels tend to be rather unstable – again, see the Nedelin catastrophe – and so there’s an upper limit on just how volatile you want to make that. What about the rocket nozzle? How wide/narrow this is determines the pressure at which the exhaust gases exit the rocket. For reasons I won’t go into, rockets produce the maximum amount of thrust when the pressure of the exhaust gas equals the pressure of the ambient atmosphere through which the rocket is flying. Atmospheric pressure decreases as you ascend into space, so ideally you want a rocket nozzle that automatically adjusts in size with altitude to keep the rocket working as efficiently as possible. This has been done. After that, there’s no real way to further improve a chemical rocket. We’ve taken them just about as far as we’re going to.

Solution 2: Don’t launch them from Earth.

One of the attractive things about a Moon colony – aside from the whaling opportunities – is that the Moon has a gravitational pull less than one-sixth that of Earth’s. It has an escape velocity of 2.38 km s^-1, and consequently it would only take 2.83 MJ to get one kilogram of mass out of the Moon’s gravity – under a twentieth the energy you’d need to get the same kilo off of Earth! Probably the best way to illustrate this is the ascent module on the Apollo lunar landers; that little capsule was able to create enough thrust to return to orbit to rendezvous with the command module.

It would be far easier, therefore, if we could somehow launch rockets from the Moon instead. Unfortunately this idea merely replaces the problem of getting out of the Earth’s gravity well with the even larger problem of building the necessary industrial base on the Moon to build and launch rockets. I’m not saying it couldn’t be done, and if somebody did manage to do it there’s every chance we’d see the commonplace spaceflight depicted in movies like 2001 (if you were lucky enough not to live on Earth, anyway), but the level of commitment and resources it would require would be staggering.

Solution 3: Mass drivers.

This one is simple, and operates on the principle that while achieving 63 MJ per kilo is a tall order for a chemical rocket, if we could somehow use electricity instead it’d be far easier to generate the energy required. The idea is you have a long, long, long, long launch track, kind of like a very high-tech version of Japan’s bullet train network (see maglevs for further information), and you accelerate the thing you want to launch down this track using superconducting electromagnetism. The track slopes upwards towards the end, and so once it reaches the end of the line your launch vehicle is shot into the stratosphere. At this point some small rocket boosters would take over and move the launch vehicle to the desired orbital trajectory. Building this thing would be a bit more feasible than the Moon colony, but there’s just one tiny snag: room temperature superconductors capable of carrying the currents required haven’t been invented yet.

Solution 4: Project Orion.

In which the Orion spacecraft is supposed to fart out shaped nuclear explosions, the brunt of which is directed against an impact plate on the ass of the spacecraft which makes the nukes “push” the spacecraft along. Utterly, utterly mad.

Solution 5: A space elevator. Also unicorns.

A very old concept that’s rather in vogue in 4X games, for some reason. As mentioned here geostationary satellites orbit the earth with a period of one day – that is, they remain above the same point relative to the Earth’s surface throughout their orbit. In theory, if you had access to a material strong enough as well as the combined and focused resources of the largest superpowers on Earth over a half-century or more, you could lower a cable from geostationary orbit all the way down to the surface of the Earth and simply have vehicles ride up and down the cable just like an elevator car. This is attractive because the energy costs are similar to those of a mass driver launch with the added bonus that you get most of it back as elevator cars come back down from orbit. If we then wanted to launch stuff further out into the solar system we could take advantage of the fact that the space elevator would kind of act like a giant sling to any payload launched from the far end.

Sounds fun, right? Perhaps so, but space elevators have several minor niggles past the huge advances in space technology, robotic manufacturing, materials science and megastructure construction (I just made that last one up, but someone’s going to have to invent it before they can build the elevator) that would be required, not to mention the totalitarian world government that’d have to be in place to keep everyone pointed in the right direction long enough to finish the bloody thing.

• In order to make it work you need a big counterweight of some kind to produce the necessary centrifugal force to keep the elevator cable taut. These days space elevator designs merely pay out the cable a little further past geostationary orbit to provide a counterweight mass rather than the previous idea of moving an asteroid to GEO to act as counterweight, but even if you do this you still need the asteroid because a) you need to build the elevator from both ends at once and so you’re going to need a base of operations in space from which to do it, and b) an asteroid would provide necessary raw materials for cable construction. So first you need to move several million tonnes of rock into geostationary orbit. This is just a little bit tricky to do, and I imagine it might make people down on the surface a little bit nervous as well what with the potential consequences if something goes wrong.

• There is no material which can currently be mass-produced in the quantities required which has the necessary tensile strength to support thousands of kilometres worth of its own weight. People always point to carbon nanotubes as the catch-all solution, but while they have the theoretical capacity to support the quantity of mass required, it would require the cable to be structurally flawless over its entire 40,000 km-odd length. Even one flaw would introduce a weakness which could be potentially fatal to the whole shebang.

• Transmitting power to the elevator cars is also going to be a bit of a bugger, since you still need that 63 MJ/kg to get into orbit. A nuclear power source would do it, but that’d probably make passengers a bit uncomfortable. Solar panels would increase the weight of the car, while using the cable itself to transmit power is going to run into the very inefficiency problems the space elevator is supposed to avoid. The current favoured proposal is wireless energy transfer via lasers or something, which has the tiny drawback that it is literally space magic.

• Elevator cars would travel fairly slowly, with an ascent to GEO taking anywhere from 6-12 hours to a full day. This brings the Van Allen radiation belts into play; the cars would travel through them slowly enough that anyone inside would end up taking lethal doses of radiation. It would be necessary to shield the cars in some way, which again would add to the weight.

Personally I think the space elevator is the ultimate manifestation of Archimedes and his lever; something that is theoretically possible but practically stupid. We can’t even agree on the best way to fly three people up to LEO; we abandoned the moon after sending barely two dozen guys up there. We are nowhere near being ready to take on the incredible engineering challenges of building something like this, and so anyone who thinks the space elevator is going to be built in the next half-millenia needs their head examined.

Where do I think the likely future of spaceflight lies? Well, assuming the world doesn’t enter a period of terminal dystopian senescence in the next couple of decades I think the mass driver concept is probably the most feasible solution as long as somebody comes along to solve the superconductor problem. It’s the smallest engineering project, it has the very great advantage of the thing being built on Earth rather than in space or on another planet, and it has the fewest question marks over necessary technology advances. Plus, if aliens ever try to invade we can use it to shoot rocks at them. Welcome to Earth.

The post The Future Of Spaceflight. appeared first on The Scientific Gamer.

On Monday there were words about the various types of manned spacecraft we’ve flung into orbit (and beyond). Particularly discerning readers will have noticed that the vast majority of them — Vostok, Voskhod, Soyuz, Mercury, Gemini and Apollo – were designed and launched within a single decade between 1960-1970. Since then we’ve had exactly one new manned space vehicle: the Space Shuttle. Manned spaceflight has been more or less left to stagnate by national governments, but there are promising signs that the next decade may be as groundbreaking as 1960-1970. Are governments becoming interested in spaceflight again? Hardly. The US government is still dragging its feet over the design and development of the MPCV, while I’ve heard very, very little about the proposed replacement for Soyuz (on the other hand that doesn’t really need replacing since it does what it’s supposed to extremely well). No, what’s going to be exciting about the next ten years is the opening up of human spaceflight to a variety of commercial efforts.

If you know me you’d probably expect me to hate the idea of private companies going into space, but to be honest governments have ignored it for the last fifty years and there’s at least a chance that profit will provide the driving force that simple discovery could not, so I’m broadly in favour of it. Regardless: not only has development of private “spaceflight” been in progress for a decade or so what with Virgin Galactic and all, but the US government recently initiated something called the Commercial Crew and Cargo program (CCC, or C3) whereby they subsidise the development of several different private spaceflight efforts with the view to buying or leasing the most suitable vehicle once development is complete.

It probably sounds inefficient to pay private companies to develop spacecraft that you then have to pay to use, and that’s because it is. It’s very inefficient. However, going up to LEO is relatively routine these days and by subsidising private efforts NASA ensures that the private sector has the technology base to take up any slack created by them abandoning LEO. And they are abandoning it; the MPCV mentioned in the last post theoretically has the capability to do LEO, but the ultimate intention of the program is to return astronauts first to the Moon or a suitable nearby asteroid, and then eventually in a few decades to possibly put a man on Mars (I nearly said person, but you know it’s going to be a guy). As it is they have to pay the Russians to make flights up to the ISS, so why shouldn’t they give some of that money to their own commercial efforts? It makes a twisted sort of sense, if you think about it.

Anyway, there’s several different competitors vying for a slice of the C3 pie. Excluding the Mickey Mouse effort of Virgin Galactic (which is literally a plane that goes really high rather than a true spacecraft), these private spacecraft are:

Boeing’s CST-100 – This catchily-named capsule is basically a space bus with a very simple design brief: deliver anywhere from between two to seven astronauts to LEO and then return them to Earth. It’s not going to go any further than that because it doesn’t have the capacity to do so.

Sierra Nevada’s Dream Chaser – Like Boeing’s effort, designed to take up to seven astronauts to LEO and back. You may notice that it looks like a miniature space shuttle, but the Dream Chaser launches on top of a rocket booster just like a capsule does. The wings and whatnot are just to allow it to land on a runway instead of splashing down in the ocean.

SpaceX’s Dragon – The interesting one. Like CST-100 and Dream Chaser, Dragon can do LEO with no problems, but it also has the theoretical capacity to go further – perhaps even to the Moon. It’s also the only one of the three private efforts to have actually made an unmanned test flight into orbit, so it actually does work. This got them noticed by NASA and they’ve been awarded a contract to resupply the ISS, so this is the one you’ll most likely see flying in the next decade or so.

In theory, then, that’s LEO taken care of. What about going further afield? You may or may not remember some hullaballoo about five or six years ago when President Bush announced the Constellation program. This was supposed to set NASA’s manned spaceflight goals for the next quarter-century, and those goals were lofty: to return to the Moon, to establish a permanent base there, and to put a man on Mars by 2030. Even the most insufferably optimistic space scientists thought that achieving all this on such a short timescale was a little unrealistic (it could be done with enough money and political will, but NASA doesn’t have anywhere near that much in their manned spaceflight budget), and sure enough when Obama was elected one of the first things he did was cancel the Constellation program. This meant that the proposed Ares heavy rocket booster and the Altair lunar lander were both cancelled, but what didn’t get cancelled was the Orion space vehicle (similar to the Apollo command and service modules). They couldn’t cancel that because despite the shifting political winds they still needed a replacement for the shuttle – which had been pushed far beyond its projected operational lifetime – and Orion was the best they had.

So Orion morphed into the Multi-Purpose Crew Vehicle. This is a four-man spacecraft designed to be launched on refurbished shuttle rocket boosters, and it’s multi-purpose because it can, theoretically, do pretty much any manned mission we can think of. Want to make a trip up to LEO? No problem, just launch the capsule. How about a near earth object? Stick a service module on it to extend its flight time and send it out there. Mars? Even that’s doable if you daisy-chain several service modules together to increase power, life-support and fuel capacity. This is the great advantage of a modular capsule design: it is hella adaptable in comparison to a fixed-mass spacecraft like the shuttle. It’s a great design if they can pull it off; an unmanned test flight of the Orion is scheduled for 2014, although I really wouldn’t expect to see it flying with people inside until the 2020’s at the very earliest.

Other countries are also looking at getting into space; Japan and India both have nascent manned spaceflight programs, while the European Space Agency was somewhat put out when NASA announced they wouldn’t be accepting international participation in Orion like they did with the shuttle, thus forcing ESA to start developing their own solution pretty damn quickly; it currently consists of a jury-rigged version of the unmanned Automated Transfer Vehicle that carries supplies up and down from the ISS. All of these plans are still very much on the drawing board though, and it usually takes a spacecraft design at least a decade to actually make it off the drawing board and into space – and as the Chinese have proved, even then it can be a slow, arduous process developing the technology. No, I think that in the future LEO will belong to Soyuz and the commercial spacecraft, with the MPCV providing a longer-range option should we ever want one.

The post A Brief History Of Spaceflight, Part Two. appeared first on The Scientific Gamer.

Following on from why the Space Shuttle sucked, I’m going to do a little summary of manned spaceflight – both where it’s been, and where it’s going.

You’d have to look pretty hard to find someone who didn’t know that Yuri Gagarin was the first man in space in 1961. However, finding someone who doesn’t have a clue what the hell he was flying would be significantly easier. Gagarin made Earth orbit in what was essentially a tin can strapped to a converted ICBM. The tin can was called Vostok, and it was incredibly basic; it was a metal capsule containing the cosmonaut attached to an equipment module with RCS¹ thrusters and a small rocket engine to make the re-entry burn. Vostok amuses me because once the re-entry capsule had separated from the equipment module the cosmonaut had no way of controlling his re-entry – no thrusters, no parachutes, no nothing. Well, I suppose they did have parachutes, but only in the sense that the cosmonaut would physically have to eject from the capsule and parachute down before the capsule smashed into the ground. Still, it proves that you can do spaceflight in an incredibly basic way if you’re willing to economise.

The American Mercury program was next; this is slightly better known thanks to Freedom and Hollywood and whatnot. Alan Shepard was beaten by Gagarin’s flight by a mere month, but what the films and documentaries tend not to emphasise was that Shepard’s flight was sub-orbital – i.e. there wasn’t a huge amount separating it from a regular aeroplane flight except the altitude. It wasn’t until 1962 and the third Mercury flight that NASA finally achieved a stable orbit. On the other hand the problem lay more in the Redstone rocket boosters they were using than the Mercury spacecraft themselves; compared to Vostok it was a model of sophistication, with a conical shape for controlled re-entry (this is important because you only have to plaster your heat shield along the flat bottom of the capsule rather than shielding the whole thing as they had to do with Vostok), limited fly-by-wire maneuvering capability and a parachute for a “soft” splashdown into the ocean². Most of this was down to the direct participation of the Mercury Seven astronauts in the design process – they were aviators³ used to being in control of whatever they were flying, and so they demanded features like a bigger window and a manual re-entry control system.

Mercury and Vostok were essentially proofs of concept. We knew spaceflight could be achieved, and now it was time to do something with it. That something was the space race for the Moon. Pretty much every single thing the Americans did post-Mercury had the final goal of supporting the Apollo program and the Moon landings. By contrast, while the Soviets had the same general objective they were more concerned with space “firsts” – first EVA, first space station, first probe around another planet and so on. This is one of the reasons they went running up the blind alley of the Voskhod programme.

Voskhod wasn’t even a second generation spacecraft – not really. It was simply a Vostok capsule modified to take two cosmonauts instead of one, and it retained most of the limitations of the Vostok capsule. Improvements in the boosters used to carry them into space meant that Voskhod had a braking rocket added which allowed for a “soft” descent on land with the cosmonauts still inside, but otherwise it was basically the same spacecraft. Jury-rigging Vostok in this way meant the Soviets got two of their firsts – first multi-person spacecraft, and the first spacewalk⁴ – but since Voskhod was a technological dead end it turned out to be mostly wasted effort, with only two flights being made.

Gemini on the other hand was a pure technological testbed for Apollo. There were ten manned Gemini flights over a two year period in 1965 and 1966; not only were these testing the systems and procedures required for multi-person spaceflights, they were also testing the maneuvers that would be necessary for a Moon shot – docking two Geminis in orbit, endurance spaceflights, that sort of thing – and giving the Gemini astronauts valuable experience in these manuevers that they would later find useful on Apollo missions. Design-wise Gemini superficially resembled a larger brother of Mercury, but the internal mechanisms were very, very different. In particular where the Mercury spacecraft combined its critical systems like power and life support into the Mercury capsule itself, Gemini hived these off into a separate equipment module similar to Vostok. This laid the groundwork for the modular construction of Apollo.

Not that the Soviets were sitting around all dejected after the relative failure of the Voskhod programme. They started design work on the Soyuz capsule in 1963, with the first generation Soyuz flying in 1967. Soyuz was intended to be part of the Soviet Moonshot⁵; the idea was that it’d make up part of a modular spacecraft attached to a lunar lander in the same way as Apollo’s command/service module. Soyuz has the same sort of construction, with orbital and service modules that contain all the stuff the spacecraft needs while it’s actually in space which is then jettisoned before landing to make the re-entry module’s job easier. An unmanned Soyuz capsule even made a test flight around the Moon in 1969. You can essentially think of it as the Russian equivalent to Apollo – and while you’re thinking about that, consider that while it’s undergone several generations of redesigning the Soyuz spacecraft is still flying today ferrying astronauts up to the ISS and back, albeit in a heavily modified form. Imagine what NASA could have done had they stuck with Apollo instead of putting all their hopes in the space shuttle.

Speaking of Apollo, there’s a decent argument to be made that it represents the peak achievement in manned spacecraft design. The modular construction meant that it could be tailored to a specific mission – there’s no reason an Apollo capsule couldn’t make routine flights to LEO just as well as it flew to the Moon – and considering it had to keep astronauts alive during the most insanely ambitious and dangerous missions in the history of manned spaceflight it speaks volumes about how well it was designed that it did an astonishingly good job, with only three astronaut fatalities when Apollo 1 caught fire on the launch pad.

This is why I think Apollo is so amazing (and indirectly, why I think the space shuttle was so terrible). Here is a picture of an Apollo spacecraft.

The big cylinder with the rocket is the service module with life support, power and propulsion systems⁶. The small cone on top is the command module which contains the astronauts during flight and re-entry. The service and command modules would be launched into space together on top of a Saturn V, and then they’d dock with the lunar module in Earth orbit before switching to a trans-lunar orbit.

Everyone got that? Right. That was spacecraft design in 1969. This on the other hand is spacecraft design in 2012. It’s the proposed design for what used to be the Orion spacecraft, part of the Multi-Purpose Crew Vehicle system that’s supposed to replace the space shuttle. Note the way it looks exactly the goddamn same as Apollo. That’s how good Apollo is: when today’s NASA engineers were asked to design a next-generation spacecraft, they used Apollo as the blueprint.

Aaaaanyway. After the Moon landing everyone kind of lost interest in space flight as a national pursuit, and the design of new spacecraft stagnated. The US launched the last Apollo in 1972 and haven’t made a manned spaceflight that didn’t involve the space shuttle since.  The Soviets – and then the Russians – continually refined the design of Soyuz and made great advances for the long-term human habitation of space with their Mir space station, but they too are somewhat stuck in the past as far as manned spaceflight is concerned. China is the only other nation with an operational manned spaceflight program; while people sneer at their Shenzhou capsules as barely being at the Gemini level of technology, you have to remember what I said about the MPCV – NASA is still using the Apollo design after running down the blind alley of the shuttle for the last thirty-five years. It’s the launch rate that concerns me, with the Chinese managing just three manned missions in nine years. They’re not going to make any progress if they don’t physically launch the things into space with taikonauts inside.

So spaceflight has been rather static for the last forty years. It’s only now starting to take off again (har) and the major driving force behind that has come from a rather surprising source: the private sector. More on that on Thursday.

1. RCS stands for reaction control system; if you want to make a small adjustment to the trajectory of something flying through space the best way to do it is to squirt a small amount of pressurised gas in the opposite direction and let Newton’s third law do the rest. That bit in WALL-E with the fire extinguisher? That was scientifically accurate.
2. American capsules all splashed down into the ocean. Soviet capsules all landed in Siberia or the deserts of Kazakhstan. Why is this? It’s a more a divergence in the cultural design philosophy than anything else — both methods are equally valid in their fulfilment of the main requirement for a spacecraft landing site: that it be really, really, really hard to miss.
3. Flying ability wasn’t really necessary for astronauts, except in so far as it demonstrated their ability to handle very complex machines. However what was useful was their complete self-confidence and conviction that they could handle anything, which was a trait common to combat pilots.
4. Which nearly went comically awry when Alexei Leonov realised his air-filled spacesuit — which he’d clambered into in the pressurised cabin of the spacecraft — had inflated in the vacuum of space to the point where he could no longer bend his joints to get back inside the airlock. His problems didn’t end there, either; Voskhod 2 overshot its landing site by some 400km and the two cosmonauts ended up spending a very chilly night in the Ural mountains before they could be recovered.
5. The Soviet moonshot didn’t fail because their spacecraft were bad. It failed because they couldn’t get their heavy lift rocket launch vehicles working properly before the Americans landed, thus cementing my opinion that Rockets Suck.

6. Putting all the critical systems in one place does have a drawback, as the Apollo 13 disaster demonstrated. An exploding oxygen tank damaged the service module, and because the astronauts didn’t know how bad the damage was they couldn’t trust any of the systems contained on board – including, critically, the large propulsion engine that they’d normally be using to adjust their orbital trajectory. If they hadn’t had a convenient set of backups in the form of the lunar module life support systems and descent engine, the Apollo 13 astronauts would have been screwed.

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