Science and Tech

5 Ways Reusable Rockets Will Carry Us to the Stars

futurerocket 030916 fb

Be sure to check out part 4 of this 5-part series: “ 5 Ways Brain-Computer Interfaces Could Change The World – And Us.”

How difficult, costly, and energy-intensive is it to get mass from Earth’s surface into orbit? Let me put it this way: At one point, the United States government seriously looked into the possibility of ditching rocket engines in favor of equipping spacecraft with giant metal plates and propelling them into space with nuclear explosions.

Rocket Launch NASA

If you want to know why real human spaceflight falls so far short of many people’s hopes, the extreme challenge of even getting off Earth in the first place is at least half your answer. The Earth accelerates everything downward at a rate of 9.8 meters per second squared. You must fight that every moment of your trip on the way up, and that takes a lot of energy. Once you’re in space, you’ll need sufficient orbital speed if you want to stay in space for long, and that takes even more energy. You need huge, powerful rockets with huge, powerful fuel supplies to get anything up there. Those rockets and fuel are heavy, and they need to accelerate not only the cargo’s mass but their own, which demands even more energy.

None of that is free. Even with the most cost-effective spacecraft in use today, it costs over two thousand dollars per pound to launch cargo into orbit. Even that is a huge improvement over the past. Space launches by private companies were de facto illegal in the United States until a few years ago, preventing price competition and strangling possible private-sector innovations in the cradle. Happily, that is no longer the case.

On December 22, 2015, private space launch company SpaceX made history with the 20th flight of a Falcon 9 rocket. After launching from Cape Canaveral and delivering its cargo of communication satellites into orbit, the rocket’s first stage did what no space vehicle has done before – returned to Earth and safely performed a vertical landing.

That’s a big deal, because a big part of the reason spaceflight is so expensive is that the vehicles aren’t normally reusable. Once their fuel is expended and their payload released, they plummet back into the atmosphere and burn up. The most prominent previous attempt to build a reusable spacecraft, the Space Shuttle, turned into a hideously expensive boondoggle. The private sector may be able to do better.

But there’s still a ways to go. SpaceX will need to be able to recover both stages of its rockets, refurbish them for reuse at a reasonable cost, and do all this quickly enough that the rocket is ready for another mission in a short time if they’re going to achieve the sort of cost reductions they’re hoping for.

But if they – or one of their competitors – can pull it off, space flight could become dramatically less expensive and more frequent. This wouldn’t just make the stuff we already do in space cheaper and more accessible – it could open up whole new fields of activity that are currently the stuff of science fiction. Factories in space, terrifying orbital weaponry, the chance to experience outer space firsthand opened up to thousands of people, the colonization of other worlds, and more – all would be in much closer reach. Let’s take a closer look.

1. Industry

It’s not accurate to say that objects in Earth orbit are in “zero gravity.” Or even “microgravity,” though that’s often touted as a more precise, correct term and is what I’ll be using in this article because I have low resistance to peer pressure.

At the altitudes where most manned spaceflight takes place, only a few hundred miles up, you’re still close enough to Earth that its gravity actually isn’t much weaker than it is back on the surface. Astronauts float because a spacecraft in orbit is in a continuous state of free fall, with no forces other than gravity (such as atmospheric lift or the Earth’s surface reacting to gravity pushing mass against it) acting on it. No external contact forces, no weight, even though there’s still gravity.

Whatever you want to call it, though, it makes for an environment radically different from what we’re accustomed to on Earth. Things that are difficult or impossible to do down here can become possible or even easy in space, and vice versa. This has a lot of downsides – simple tasks can become awkward, muscle and bone atrophy for lack of stimulation, and without millions of dollars worth of microgravity toilet technology, the interior of any spacecraft would quickly become something beyond a hardened bus station janitor’s most fevered nightmares. But it’s also one of the things that could make space a valuable location for the industries of the future – provided, of course, that you can get up there at a reasonable cost.

international space station

For example, some types of crystals grow more quickly and with fewer flaws in microgravity. An orbital facility might be able to produce semiconductors, polymers, and protein crystals of a quality unseen on Earth. Many materials refuse to mix with each other under normal conditions but can be mixed while weightless, allowing for the creation of previously impossible metal alloys. (Microgravity is for materials science what booze is for human relationships, apparently.) Microbes often undergo metabolic changes in microgravity, producing new biochemicals that could be useful in medicine or industry.

Weightlessness is not the only useful thing about being in space. Some manufacturing processes, such as the chemical vapor deposition used to create valuable new materials like synthetic diamonds, thin film electronics, and graphene, need to be done in a vacuum, and space has no shortage of that. You can use focused sunlight to heat materials to high temperatures, or keep them permanently in the space station’s shadow to make them very cold. The ability to simply throw people out of an airlock could radically streamline labor disputes. And so on.

Some of these applications will likely have to wait until we have access to minerals from a non-terrestrial source. Even with reusable rockets, heaving ton after ton of raw iron or silicon from the bottom of a planet-sized gravity well into Low Earth Orbit to feed your orbiting factory is unlikely to be cost-effective, no matter how fabulous the computer chips or exotic alloys you’re making are. If you can get raw materials in Earth orbit without having to go through that, on the other hand – by, for instance, mining nearby asteroids – orbital manufacturing starts to look a lot more feasible. And reusable rockets would make that a lot easier, too.

2. Tourism

Who wouldn’t leap at the opportunity to visit space? Well, I wouldn’t, since I get scared if the car I’m in breaks the 30 miles an hour barrier. But a lot of people would.

And you can! For just a few tens of millions of dollars, Russia’s Federal Space Agency and their private American sector partners at Space Adventures, Ltd. can send you into Earth orbit to spend several luxurious days at the international Space Station. Eight people have done it, including legendary game designer Richard Garriott.

And they’re not stopping there: Space Adventures is already planning a pleasure cruise around the far side of the moon. They say they’ve already sold one ticket for the flight, which doesn’t sound like much until you learn that whoever bought that ticket paid $150 million for it.

Space Adventures

Of course, you might not have $20 million to spare. Substantially decreasing the cost of launches could bring down the cost of space tourism considerably, making it more widely accessible. Making it more widely accessible would in turn allow for economies of scale that aren’t really possible when your business model is “send one insanely rich guy into space for a week once a year.”

It’s still not going to be cheap. Even under the most optimistic estimates of how much reusable rockets could reduce the cost of space travel, it’ll still be far more expensive than a normal vacation. But it could still become a real possibility for far greater number of people than it is now.

To date, all space tourists have stayed at the International Space Station. Any significant increase in the number of private citizens taking a trip into space will require the creation of new accommodations for them. This could take the form of spacecraft that can accommodate a group of human passengers for several days or weeks before landing, or – perhaps more cost-effectively, since you’d only have to launch it once – permanent facilities in orbit that tourists are shuttled to. Space hotels, essentially.

These facilities needn’t be single-use, some might be incorporated into, and perhaps even help to subsidize, other facilities like laboratories or factories. In this way, seemingly frivolous activities like millionaires paying to have really awkward zero gravity sex in Low Earth Orbit could help support the infrastructure for further expansion into space.

3. Military

There’s been much high-minded talk from great statesmen over the decades about not militarizing space, common province of all mankind, yadda yadda yadda, but the truth is that it’s easy to be high-minded about temptations you don’t actually face. The incredible cost of getting into orbit has made putting weapons up there too costly to be worth it. If you’ve already got enough nuclear Intercontinental ballistic missiles to turn every city in the Soviet Union or the United States into a molten lake many times over, putting your nuclear weapons on an orbiting satellite so they can reach their targets a few minutes faster is sort of pointless. Moscow isn’t going to demand a refund if you fail to incinerate it in 30 minutes or less.

Greatly reduce the cost of putting mass into orbit, and… Well, announcing your new diet on New Year’s Day after the festivities of the holiday season have stripped your cupboards bare is one thing. Staring down the barrel of a box of Thin Mints and saying “You cannot pass” is another.

The most likely near future space weapon is not nuclear bombs, or conventional missiles and shells, or some sort of orbiting laser or particle beam weapon. Instead, the space super weapon of the future is probably… metal poles.

Nuclear Explosion

The weapons would be based on an orbiting satellite, carrying a magazine of tungsten rods. These would be much longer than they are wide (the best-known proposed design called for them to be 20 feet long and 1 foot wide), shaped to minimize air resistance, and carry no explosive warhead. Just solid metal, save perhaps for some maneuvering fins and a guidance computer.

When it’s time for somebody to die, the satellite launches one of the rods on a trajectory that will make it fall from orbit and hit the desired target. After the initial push at launch, Earth’s gravity does the rest of the work, rapidly accelerating the projectile towards its target. Air resistance would slow it down again considerably on final approach, but when the projectile finally hits the ground it would still be going at around Mach 10 – about 7,680 miles, or 12,360 kilometers per hour!

Getting from Earth’s surface and orbit takes a lot of energy. The flipside is that something falling out of orbit all the way back to Earth brings a hell of a lot of energy back with it. Even after losing most of its speed to friction with the atmosphere, a tungsten cylinder of the dimensions described above would deliver the same kinetic energy as about 11 1/2 tons of TNT on impact.

That’s a lot, more than any conventional weapon ever confirmed to exist on Earth – but not enormously more. The yield of the GBU-43/B Massive Ordnance Air Blast (aka the MOAB) is almost as high, and a lot less expensive. A kinetic weapon launched from orbit has other advantages, however.

The projectile would penetrate deeply into the ground, deeper than any conventional “bunker buster” bomb, allowing it to reach otherwise impregnable underground facilities. It would take less than 15 minutes for a kinetic weapon fired from orbit to reach its target, and a small network of satellites would make it possible to get any target on Earth within that time.

And anyone trying to defend against such an attack would find themselves in the unenviable position of trying to stop several tons of solid metal hurtling towards them at 10 times the speed of sound.

4. Power

In a world where most of our electric power comes from sources that are limited in quantity and produce all manner of horrible byproducts, solar power has tremendous appeal. We have a clean, safe, and effectively endless source of power, provided free of charge by a colossal nuclear reactor that nature was kind enough to build for us. Why not take advantage of it?

Unfortunately, the surface of the Earth isn’t the most favorable position for collecting solar power. The planet’s rotation leaves a solar collector cut off from sunlight much of the time. When the sun can reach the collector, half of its arriving energy gets absorbed into the atmosphere before reaching the ground. And that’s if you’re lucky – if the weather is unfavorable, the clouds might block out a lot more.

The solution is obvious – don’t build your solar panels on Earth! Put them in space. Obvious, and impractical – putting all that infrastructure into space would be terribly expensive, and if something needs repairs you can’t just pop into space on a few days or even weeks notice to fix it.

For the present, at least. Drastically decrease the cost of space travel, and collecting solar power in space may start to become more attractive.

ISS Solar Power International Space Station

A solar power satellite in a geosynchronous orbit over the Earth’s equator could stay in direct sunlight almost nonstop, falling into the Earth’s shadow for only a few minutes per year. That sunlight would be much stronger than what reaches the Earth’s surface on even the brightest day. You’d be able to produce far more energy per square inch of solar panel then would ever be possible on Earth.

The collected power could then be transmitted to earth via either a laser or microwave beam, which would then be picked up by receivers on Earth capable of converting electromagnetic energy into electricity. Unconstrained by the need for power lines, a satellite could send power directly to numerous locations spread across a significant percentage of the Earth’s surface, directing it wherever demand is highest.

Anyone who’s played SimCity 2000 or Vanquish is probably getting a little antsy about the prospect of beaming large quantities of power from space into populated areas on Earth. Would this thing be safe?

It would actually be quite safe. Most proposed receivers for the incoming microwaves would consist of a whole field of linked receiving antennas a mile or more across, with the microwave beam spread across the entire area. The total amount of power received by the entire receiving array would be high, but the intensity of the beam at any particular spot would not be. The transmitter would not be capable of setting fire to buildings or boiling people in their own juices, whether by accident or intentionally.

Which is good, since I don’t trust my local power company to keep the electricity running in more than a light breeze, much less operate a giant death ray.

Observable universe logarithmic illustration with legends

5. Further Outward

We’ve been mostly limiting things to activities in Earth orbit, but cheaper space launches would have consequences far beyond that. The first few hundred miles from Earth’s surface after takeoff are so demanding that, once you’ve crossed them, the most arduous part of your journey is over even if your ultimate destination is on the other side of the solar system. Flying around the solar system and not just puttering around Earth’s immediate vicinity presents great challenges of its own, to be sure, especially if you want to send human passengers or crews. But making it relatively cheap to get into space in the first place would take an enormous bite out of the cost of getting from Earth to Mars, the asteroid belt, or any other place in our solar system you might want to reach.

And there are all sorts of places you might want to reach. Mining asteroids would be a fantastic source of raw resources for both terrestrial and orbital industry, as well as the elements necessary for life support and fuel. Ironically, chief reusable rockets could eventually allow us to create an infrastructure that makes them less necessary, as more and more of the materials and equipment needed in space can be mined and manufactured in space rather than on Earth.

The growth of tourism and industry in orbit would mean more and more people living and working in space, which presents a new problem – extended periods of weightlessness are bad for you. Muscles atrophy, bones weaken, sleep is disturbed, flatulence grows worse… (No, seriously.) People won’t want to work in space for extended periods if they’re going to come home looking like the Crypt Keeper. In the long term, we might start creating dedicated habitat stations that could be spun on their axis to create artificial gravity through centrifugal force. With enough activity going on in Earth orbit, these might eventually grow in size to contain full-blown towns.

And there’s one area where being able to cheaply carry mass from Earth’s surface into space would be absolutely indispensable: Colonization. A human settlement on the Moon or Mars or beyond might be able to get its minerals from asteroids, its machinery from space-based industry, and its water from carefully redirected comets. But it will still need to get people from Earth – a lot of people, if it’s going to be a permanent society in its own right and not just a glorified research outpost.

If the human race is ever going to expand beyond the confines of its own world, we’re going to have to fight our way out the planet’s gravity well again and again and again and again. Preferably without bankrupting ourselves in the process.

Be sure to check out part 4 of this 5-part series: “ 5 Ways Brain-Computer Interfaces Could Change The World – And Us.”


About the author