SpaceX landed its rocket, but you should know a few things

SpaceX landed its rocket, but you should know a few things

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By Ryan Faith
In case you had missed it, amid all the fanfare over the release of the latest installment of Star Wars, a great many of your nerd friends may be incredibly excited about something else related to space: That a company called SpaceX, which launches stuff, just pulled off a big important thing Monday. Now SpaceX isn’t just launching rockets; it’s landing them, too!
So you might start wondering whether to sell that second kidney you keep lugging around, book some time off from work, and start packing for a weekend in space. Sure, SpaceX has sent things into space before, like its Dragon capsule, and returned them to Earth, but the big deal is that now it has managed to safely land the actual rocket used to launch a payload into space.
Yes, it’s that big a deal — just not for you personally, at least not today. So you can quit trying to post an online ad for your kidney. To get a sense of how exciting this is in realistic terms, we need to pop through a quick spot of engineering and economics. Then you can get back to worrying about whether you can post a selfie from the lunar surface, or if you’ll have to wait until you get back.
First things first, if there’s nothing else that you need to know about space it’s that it’s insanely, mind-bogglingly hard to get there. While gravity, on the one hand, is essential because it keeps the moon in orbit around the Earth and the Earth around the sun, on the other hand it’s also a remorseless, relentless, stone-cold killjoy bound and determined to prevent you from ever personally visiting the moon.
Without getting too far into the mechanics of launch, just know this: Being in space means going faster than pretty much any human has ever gone within the Earth’s atmosphere. Way, way faster than any plane has ever gone. This means that the machinery is being pushed to the limits and is always just a jitter or two away from catastrophe. There’s very precious little design margin to screw around with unnecessary stuff.
For instance, if you were designing a plane with that little extra weight or power, it might make sense to skip all of the gear and equipment needed to land the plane. When you get to your destination, just bail out and take a parachute down, and let the jet go on its merry way. It’d be expensive, but if you’ve got practically zero margin to work with, it might turn out that a landing gear and whatnot is an unnecessary frill.
Except that transportation by crashing the vehicle on its maiden flight makes it heinously expensive to travel anywhere.
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Which is where space is today: The performance and design margins are so tight, and the technological demands so high, that, basically, anytime anyone launches a satellite into space, they don’t have room to dick around with niceties like building in enough gear or design margin to land the rocket instead of crashing it.
The Holy Grail for space launch cost is elasticity (read: “cheap enough that personally going to the moon wouldn’t quite be science fiction”). Now, economists are going to have to forgive me a bit for oversimplifying on this, but here are the essentials:
Econ folks call prices elastic when, for instance, a change in price will increase or decrease the number of people using a product. Inelastic prices are the opposite: when a small change in price doesn’t really change the number of people buying something or the amount they buy.
Think of it this way: An inelastic good might be crack cocaine. A true addict will do just about anything to come up with the scratch for another hit. And reducing prices by 90 percent isn’t going to cause a lot of people to want to take up a crack habit.
Conversely, eating out is elastic. Getting a 10 percent discount on a meal may be all it takes to get you out for dinner instead of eating leftover death from the fridge. Happy hours are the triumph of applied price elasticity: What drop in prices will get you in the front door for a couple drinks that you might have otherwise skipped?
Now, all we really know about space launch economics is that they’re pretty inelastic. After all, if you’re laying down $400 million for a couple of satellites, dropping launch costs from $140 million to $130 million isn’t going to be worth much, no matter how much beer at happy hour that $10 million will buy the engineers.
And unless you’re a professional astronaut who can safely bill their travel expenses to and from orbit, our own personal trips to the moon live down here in elastic land. We might go if it were a lot cheaper, but until then, it’s just a pipe dream.
Look at it another way: When prices are elastic, a company can actually make more money by lowering the price. If the price changes just a little bit, but gets a whole lot more customers in the door, then it makes a huge amount of sense to invest heavily on figuring out how to make stuff less expensive. And if they work on that hard enough and long enough, maybe this will keep happening, reducing costs and increasing customers.
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There are really three ways to go about getting costs down this low. The first two involve reusability. Nobody is going anywhere at all on the cheap if they have to get a new vehicle every time they want to go somewhere. For instance, in a call, Elon Musk, head honcho at SpaceX, explained that a Falcon 9 rocket costs $60 million to launch, but the propellant runs about $200 grand. If you can skip the cost of that $60 million vehicle and bring launch costs down to fuel alone (kind of the way that we operate cars), then that’s a 99.67 percent drop in cost for each trip.
The first way to tackle reusability is to start with something that’s already reusable and then try to figure out how to get into orbit with it. This is the approach of Virgin Galactic and Blue Origin. In fact, Blue Origin just pulled off a successful landing a little less than a month ago (even if it just barely stuck its nose into “space” by going just over 100 km — about 60 miles— up from the surface). Heck, in 2004, Virgin Galactic demonstrated reusability by getting the same vehicle to do the same suborbital jaunt twice in a two-week period.
But that kind of suborbital jaunt is a far cry from getting into orbit, because orbital speeds are so much higher and have such small margins. This gives us the second way to tackle the problem, which is building something that goes into orbit and then fiddling with it to see if it’s possible to squeeze in a reusability around the margins. Even if you lose a big chunk of your payload doing it, it still beats launching a new rocket each time; just tell people to make smaller satellites.
You can try to do both things at the same time, which is sort of what NASA did with the space shuttle. But that didn’t work particularly well in the end. Rather than being a way to develop a reusable space vehicle that could go into orbit and operate on the cheap, the shuttle turned out to be heinously expensive — call it maybe 150 to 200 percent more than traditional disposable rockets.
Which brings us to the third approach to getting cheap spaceflight: using some “non-traditional” or “exotic” way to get stuff into space. There are a zillion other PowerPoint presentations, cocktail napkin doodles, and BS online discussions about ways to do this but they, much like the two approaches outlined above, need to get past a critical first test: “Can you prove to me your concept isn’t utter bullshit?” Which brings us to the necessity of the “existence proof.”
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For any big super technological advancement, it helps a lot to have an existence proof. Murphy’s Law and everyday life tell us that folks should just come to expect that everything is a lot harder in practice than in theory. Space is a lot like that, too.
Demonstrating that something is even possible (i.e. an existence proof) doesn’t mean that people aren’t going to start seeing stuff pop up on the street corner tomorrow. It means we’ve gotten past two of the most important questions you should ask when someone proposes something radically complex and incredibly difficult: “Are you f’ing kidding me?” and “Are you out of your goddamn mind?” A good existence proof means you can answer both questions with a provable “No.”
A most important example of an existence proof for space was the moon landings. Whoever goes there next will certainly use more advanced technology, but it pretty firmly established the fact that President John F. Kennedy’s 1962 promise to send people to the moon wasn’t just for show.
Interestingly, the shuttle was supposed to be an existence proof of reusability leading the way to low-cost access to space. It says a lot that the country who landed guys on the moon (and brought them back for interviews and photo ops) could only deliver an existence proof for (mostly) reusable vehicles, but no proof for the making-it-cheap business.
With all that in hand, we can get back to what SpaceX has or hasn’t done and whether it is or isn’t a big deal.
The SpaceX rocket is not the first reusable vehicle to go into space. Three US efforts — the space shuttle, Virgin Galactic, and Blue Origin — have all demonstrated that.
It’s not the first reusable orbital vehicle; that was demonstrated by the space shuttle back in 1981.
For that matter, it’s not even the first “commercial” space vehicle to demonstrate reusability via vertical landing; that honor is shared with Blue Origin.
It is, however, the first to hit all three of these things: reusability, orbital capability, and not insanely expensive and fussy. Getting all three of these is a big deal, just like winning the Triple Crown in horse racing is a big deal. Hitting two of three and falling short means you’re important only in the realm of horse racing aficionados. One gets headlines, the other is good fuel for speculation and an admonition to do better next time.
So in this way, a SpaceX demonstration of reusability is an important existence proof, right? Except that if you want to be really technical about it, then no, not really. They just recovered a booster, but haven’t relaunched it. They certainly haven’t done anything on recovering the second stage of the rocket. And some bits, like the part that connects the first and second stage of the rocket, may never be recoverable.
All that’s been shown is recovery of a first-stage engine and rocket in one piece. (Heretofore, the traditional recovery mode for a first stage involves an uncontrolled, very high-speed descent, followed by destruction.)
SpaceX is the first to do something other than crash landing.
But that’s super important, and here’s why: First off, the main engine and first stage of the rocket are really big and expensive parts of the rocket. It may not bring launch costs down to propellant alone, but I’ll wager good money that rockets get a whole hell of a lot cheaper if you don’t have to supply an engine and rocket body for the first stage.
Second, doing this was a ginormous engineering challenge. According to SpaceX’s website, the rocket needed to shed up to 300 gigajoules of kinetic energy in order to stick the landing. I don’t have a lot of good comparisons; 300 GJ is a whole lot of energy. The kinetic energy of a round from the main gun of a tank is about 0.01 GJ, so it’s as much kinetic energy as 30,000 tank guns firing all at once. Put another way (even if you can’t directly compare one GJ of kinetic energy with one of electrical energy), but to give a sense of scale, San Francisco uses about 1 GJ of electrical energy per second; 300 GJ of electrical energy would be enough to power that city for a full five minutes.
Making all that disappear into thin air so the rocket can daintily touch down without a digging a pretty deep crater is a no-bullshit major accomplishment — big enough to merit a lot of pretty excited and expansive press coverage.
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The difference between all those really old, super cheesy science-fiction flicks where the rocket settles on its tail and what SpaceX has done is the difference between shooting the shit about sending your future kid to Harvard and actually getting pregnant and giving birth. It’s not time to start sending out graduation announcements, but having the kid in the first place is still a pretty big deal, worth a party and some announcements, and is a first, essential step toward the long-term goal.
Think of it another way: Even if it’s not full demonstration of complete reuse, by showing that it’s even possible in the real world to land and recover a vehicle like this, SpaceX has done something very important — they’ve incrementally, but permanently shifted the debate about reusability.
Now, instead of this kind of reusability being a discussion about whether this idea is certifiably insane, it’s now a matter of ironing out some (still ginormous) details. But at least the discussion about what’s physically possible is now clearly settled. The debate has moved on to the practical side of stuff: working the design margins, polishing refurbishment processes, and all the other far less glamorous but essential things that real-life success seems so picky about.
So has SpaceX oversold this? Not in the least. Granted, some of the enthusiasm others have whipped up is over the top, but SpaceX has been playing this pretty straight, and that’s part of what makes me most hopeful. Oftentimes, some of the folks who are most wildly enthusiastic about something are those who have the least idea about what’s really going on. But if you listen carefully to how SpaceX is talking about this accomplishment — proud but measured professionalism — it tells me that SpaceX appreciates both how far they’ve come and how far they have to go. They’re not overselling; in fact, they sound like they know exactly where they’re at.
So, no, don’t start packing your suitcase for the moon. We’re not anywhere close to that yet. Right now, we’re at the point when it wouldn’t be completely insane to get measured for a spacesuit and start doing a little online comparison shopping. A couple decades out isn’t wild nonsense. We’re starting to move from fantasy to dream, and that’s a big step indeed.
Follow Ryan Faith on Twitter: @Operation_Ryan

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