Image source: Facebook.

As its recent earnings blowout clearly shows, social media giant Facebook's (NASDAQ:FB) days of heady growth are by no means behind it. The company continues to grow like a weed.

At the same time, though, the world's largest and most powerful social media empire must find a way to overcome its own set of unique challenges in order to keep its stock price heading up and to the right for years to come. Thankfully, Facebook recently moved one step closer to circumventing its most serious big-picture growth constraint.

Facebook's Project Aquila takes off

According to a recent blog post from the company, Facebook's drone-based project to expand internet access to the roughly 4 billion people without -- dubbed Project Aquila -- logged its first successful test flight.

Image source: Facebook.

For those unfamiliar with Aquila, or without the time to watch the above video, Aquila represents Facebook's most aggressive experiment to date to help bring Internet connections to the 60% of the world's population who currently lack access.

As an engineering feat alone, Project Aquila's drone is something of an engineering marvel. Designed with the wingspan of an airliner, Project's Aquila's drone is ultra-efficient and entirely solar powered. At its 60,000 cruising altitude, the drone requires as much power to stay aloft as just three hair dryers, and it provides wireless internet coverage to an area as large as 60 miles in diameter.

Though this represents a major milestone for the project, Facebook readily admits it must overcome numerous engineering, business, and political hurdles before Project Aquila proves ready for widespread deployment. However, as Facebook noted in its press release, projects like Aquila are pivotal to ensuring Facebook's continued business success as well as its purported aim of being a positive force for social change.

Doing well by doing good

In recent years, both Facebook and internet giant Alphabet (NASDAQ:GOOG) (NASDAQ:GOOGL) have dedicated significant resources toward devising new models to bring a greater percentage of the world's population online -- to varying degree of success.

Image source: Facebook.

Harnessing many of the same principles of Facebook's Project Aquila, Alphabet announced its own internet access concept, dubbed Project Loon, in 2013. Rather than using drones, though, Alphabet's Project Loon sends massive, high-altitude balloons into the stratosphere, roughly 11 miles above Earth's surface, where they can beam wireless cellular signals across wide swaths of land.

In a broader sense, Facebook and Alphabet are attempting to overcome a fundamental constraint for each of their businesses. With their internet services the market leaders virtually anywhere they aren't blocked, namely China, Alphabet and Facebook will need to find new ways to bring more people online -- or risk slowing growth.

We know Facebook currently enjoys 1.7 billion monthly active users. With 3.2 billion total people online in 2015, Facebook's market share of total possible users already hovers north of 50%. However, after backing out the 688 million Chinese internet users Facebook cannot access, the social media titan's market share can be seen as something closer to two-thirds of its potential user base. Similarly, one 2015 study from industry site Search Engine Land estimated that Alphabet's Google search engine, the company's primary financial engine, enjoyed a global market share of 75%. 

Assuming these figures are at least directionally accurate, it becomes evident rather quickly that growing by increasing their market shares alone only offers somewhat limited upside for either Alphabet or Facebook. That's why projects like Aquila and Loon are perhaps more important than many investors realize.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.