Preview: Succeed or fail, SpaceX's Falcon Heavy test sure to be a blast

At long last, SpaceX is ready to send its mythical Falcon Heavy rocket on a test flight next week. It's a huge deal, even for a spaceflight company that routinely accomplishes huge deals. An operational Falcon Heavy will make SpaceX the proud owner of the most powerful rocket system since the Saturn V*, and opens up yet another corner of the launch industry to serious competition.

The main goal of the test flight is straightforward: launch something into space without blowing up. CEO Elon Musk, never one to settle for something boring like an inert block of concrete, decided the sacrificial payload would be his Tesla Roadster, aimed for a Mars-adjacent trajectory.

"I love the thought of a car drifting apparently endlessly through space and perhaps being discovered by an alien race millions of years in the future," he said on Twitter.

I'll break down the Tesla aspect of the launch in a followup story coming out Monday, and I'll also be in Florida covering the launch in person. My boss, Planetary Society CEO Bill Nye, is scheduled to make an appearance at the Kennedy Space Center visitor's center. The first launch window opens Tuesday, February 6 at 1:30 p.m. ET (18:30 UT).

*By capacity to low-Earth orbit. After publishing this article, it was also pointed out that the Soviet Energia was more powerful than the Falcon Heavy. It flew twice in 1987 and 1988.

So, about that rocket

The Falcon Heavy is essentially three of the company's Falcon 9 rockets bolted together in a row, a design that makes it outwardly similar to United Launch Alliance's Delta IV Heavy. For those not up-to-date on SpaceX nomenclature, "Falcon” is an homage to the Millennium Falcon from Star Wars, and "Heavy" simply means the rocket can carry heavy things to space.

SpaceX revealed the Falcon Heavy in 2011, predicting it would fly as early as late 2013. Musk is known for his ambitious timelines, and it turned out the rocket's design was more difficult to perfect than originally thought. Initially, SpaceX considered equipping the Heavy with a complicated propellant crossfeed system, in which the two side boosters re-fill the center booster as the rocket ascends. When the side boosters are empty, they drop away, leaving the center core with a full fuel tank. This ultimately makes the rocket more efficient.

The crossfeed feature ended up being too complex, but even without it, the Falcon Heavy was a challenge to bring to fruition. Whereas the Delta IV Heavy has just one engine for each of its three boosters, the Falcon Heavy has nine, for a grand total of 27 engines that must all ignite and work in tandem without tearing the rocket apart. SpaceX's two disasters in 2015 and 2016 delayed things further: the 2016 accident damaged the company's only launch pad, Space Launch Complex 40, forcing SpaceX to rush to get pad 39A operational. But since there's a chance the Heavy flight will end in disaster and damage pad 39A, SpaceX also needed to get pad 40 operational again.

There's actually a further bit of controversy surrounding this point. Only pad 39A is outfitted for crew flights, which are expected to start later this year (an ambitious timeline, according to the Government Accountability Office). Should the Falcon Heavy damage 39A, how will that affect NASA's commercial crew program, which has been waiting to launch astronauts from American soil since 2011? It's a fair question, and you can bet NASA officials will be watching this demo flight with clenched teeth.

On December 28, 2017, SpaceX raised the Falcon Heavy demo rocket into position at pad 39A for the very first time, and following a month of tests and tweaks, conducted a static fire on January 24.

Look out, Delta IV Heavy

How much a rocket can lift to orbit is the result of a numbers dance between vehicle thrust and weight. You'll hear a lot of "most powerful" qualifiers get thrown around with the Heavy. When SpaceX says this, they are usually talking about how much mass the rocket can place in low-Earth orbit: 63.8 metric tons, according to the company's website. The only rocket flown successfully that could lift more than that was the Saturn V (a minimum of about 118 metric tons), and the closest challenger existing today is the Delta IV Heavy (28.3 metric tons). The space shuttle, for comparison, could handle about 24.3 metric tons.

How does this rocket fit in to the worldwide launch market? SpaceX is already a leading competitor, with two exceptions: geostationary orbit and beyond-Earth human exploration.

Geostationary orbits match the rotational period of the Earth, allowing satellites there to park over the same spot, which is good for communications, weather, and spy satellites. It takes more power to get to geostationary orbit than low-Earth orbit. The Falcon 9 can already place 8.3 metric tons into what's known as a geostationary transfer orbit, or GTO. These are waypoint orbits where a satellite can "transfer" to geostationary orbit using their own propulsion systems.

But the Falcon 9 is bested in GTO capacity by both the Delta IV Heavy (13.8 metric tons) and Europe's Ariane V (10 metric tons). Moreover, the D4H is currently the only U.S. rocket available for heavy American spy satellites. In some cases, the D4H injects payloads directly into their final geostationary orbits with no muss, no fuss, which is very appealing to the Department of Defense. But look out: The Falcon Heavy can place 26.7 metric tons in GTO, giving it more than enough margin to handle most anything the space industry currently needs.

The D4H is rarely used—about once per year, if that. And some industry experts predict we're actually moving toward smaller, more numerous satellites, rather than giant, one-of-a-kind payloads. So it's possible the Falcon Heavy won't fly that often. But SpaceX still has an advantage on United Launch Alliance here: Since the Falcon Heavy is based on the Falcon 9 and shares the same infrastructure, SpaceX probably doesn't have to spend much overhead keeping it on their launch menu. United Launch Alliance, meanwhile, currently maintains two launch facilities for two different rockets (the Atlas V and the Delta IV).

Another potential use for the Falcon Heavy is NASA's human exploration program, which has a renewed focus on the Moon. Humans require a lot of heavy equipment to stay alive in deep space, which is why it took the mammoth Saturn V to launch the Apollo missions to the Moon. This is why NASA is building the Space Launch System, which will be even more powerful than the Falcon Heavy. But SLS is expensive, and its critics have long pointed to the Falcon Heavy as a cheaper alternative.

The Heavy can't match SLS in terms of sending mass to lunar orbit. In cargo mode with its advanced upper stage, SLS can blast about 41 metric tons toward the Moon. The numbers on how much mass Falcon Heavy can send to lunar space vary from source to source, but since SpaceX says it can send 16.8 metric tons to Mars, we can assume it can do at least a little better than that for the Moon.

The main U.S. laboratory module aboard the ISS, Destiny, weighs 14.5 metric tons, so SpaceX could, in theory, launch a Destiny-sized module to lunar orbit. NASA's current plan calls for a small space station in lunar orbit called the Deep Space Gateway, with modules weighing around 10 metric tons, so that's also doable for the Falcon Heavy. However, NASA plans on launching each Deep Space Gateway module with an Orion crew capsule. Orion has an on-orbit mass of about 26.5 metric tons, making it too heavy for even a single Falcon Heavy lunar flight. So in order for SpaceX to participate, NASA's current plans would have to change. That's certainly possible, but examining how it would work from both an operational and political standpoint would take a whole other article.

Some notes on cost

SpaceX's website pegs the cost of a Falcon Heavy at $90 million. That number will get repeated a lot as the demo flight draws closer, so it's important to note it comes with some caveats. Buying a rocket is a little like buying a car: extra trim levels and extended warranties add up quickly and frequently put you above the starting price.

Case in point: Space Test Program-2 (STP-2), the Air Force launch that will carry multiple payloads to three different orbits, including The Planetary Society's LightSail 2 spacecraft. The Air Force will actually end up paying SpaceX a maximum of $160.9 million for that launch, depending on the completion of various milestones leading to launch, including mission success.

Here's why. First of all, there's oversight. The government requires its rocket providers to present lots of reviews as launch preparations progress. At those reviews, the provider updates Air Force officers and contracted, subject matter experts from organizations like The Aerospace Corporation on how things are going. If there are problems, deeper investigations may be required.

Secondly, STP-2 is a complex mission. 25 different spacecraft will be deployed into three different orbits. In addition to providing the Falcon Heavy rocket itself, SpaceX is responsible for designing and building the adapters to hold all those spacecraft inside the rocket's payload fairing, and also making sure they get deployed at exactly the right moments.

On STP-2 launch day, the Falcon Heavy will first place 12 satellites into an initial low-Earth orbit, before transferring to a circular, 720-kilometer circular, low-Earth orbit to deploy a constellation of six identical satellites called COSMIC-2, along with five smaller auxiliary payloads. (One of those auxiliary payloads is Prox-1, containing LightSail 2).

Then, the Falcon Heavy upper stage re-ignites and flies to an elliptical, medium-Earth orbit (12,000 by 6,000 kilometers), where it will drop off another spacecraft called DSX. After that, there's an Air Force certification objective to show the upper stage can coast for at least three, and ideally five, hours, before restarting for another five-second burn. To pull all of this off, SpaceX has to carefully configure the Falcon Heavy's flight software and test it to make sure it all works.

Even with all those extra options and requirements, the Falcon Heavy is still cheaper at $160.9 million than its competitors. A Delta IV Heavy flight can cross the $400 million threshold, and SLS will be even more expensive. (At one point NASA was hoping to keep the cost of an SLS flight to about a half-billion dollars, but that estimate has grown—how much depends on who you ask.)

SpaceX now routinely recovers and re-uses its Falcon 9 boosters by either flying them back to land or a drone ship in the Atlantic Ocean. For Falcon Heavy, SpaceX plans to recover all three of the Falcon Heavy's booster rockets. All three! The two side boosters will return to Cape Canaveral, and the center core will land on the drone ship Of Course I Still Love You.

There are a variety of possible outcomes for the demo flight: complete success, partial success, total disaster, loss of one or more boosters attempting to return to Earth, and the usual litany of everything that can go wrong during a rocket launch. In any case, it will be quite a thing to see.

If things go completely awry, it's unclear how soon SpaceX would continue marching through its Falcon Heavy manifest. Ultimately the big rocket is an interim solution; SpaceX plans to merge both the Falcon 9 and Falcon Heavy into a single, larger vehicle called BFR (Big Falcon Rocket, if you want to avoid expletives).

The company has already bounced back from two operational failures of its workhorse Falcon 9 rocket, so a disaster for this Falcon Heavy demonstration flight shouldn't be a huge setback—especially considering the low expectations Musk set. The only scenario that could cause the company significant problems would be if the Heavy badly damages the launch infrastructure at pad 39A and delays NASA's commercial crew program.

As far as I know, there's never been a rocket launch where the vehicle provider openly told the public there was a high chance things might end catastrophically. Succeed or fail, the demo flight is sure to be a blast!