2020: The year human spaceflight returns to the United States (maybe)

New York(CNN Business) It's an often-lamented fact in the space community: Since NASA retired its Space Shuttle program nine years ago, the public lost some of its interest in extraterrestrial happenings.

Bold rocket startups, namely Elon Musk's SpaceX, have done quite a bit to capture public attention. And many in the industry are hoping that launching people to space from US soil will usher in a new wave of support for spaceflight.

This could be the year that not one, but four US spacecraft start launching astronauts or tourists.

Two of them, SpaceX's Crew Dragon and Boeing's Starliner, are due to begin launching NASA crew to the International Space Station. And two others are slated to launch paying customers on short flights to suborbital space.

"These will be important catalysts for the space economy, awakening consumers and investors to the commercial possibilities of space," UBS wrote in a 2019 report.

Here's a look at when the biggest milestones of 2020 could arrive.

Crew Dragon

SpaceX's new capsule is in the final stages of testing before it's ready to launch its inaugural crewed mission.

As soon as January 11, Crew Dragon will conduct an in-flight test of its emergency abort system, in which the spacecraft will launch on top of one of SpaceX's Falcon 9 rockets and then jettison itself to a safe landing to simulate how astronauts will escape in case something goes wrong on the way to orbit.

That's expected to be one of the final tests for Crew Dragon before it can launch DM-2, the code name for the first test mission with people on board, in the weeks after.

Its passengers will be NASA astronauts Bob Behnken and Doug Hurley, both of whom are former military test pilots and veterans of space shuttle missions.

The exact date of DM-2 is not yet clear. NASA is anxious to get Boeing's Starliner and Crew Dragon up and running so that it can end its decade-long reliance on Russia to ferry astronauts to the ISS. Both spacecraft were expected to be ready in 2017. But testing mishaps and delays plagued their development.

Starliner

Boeing's timeline for its first crewed mission is less clear.

Its Starliner capsule launched an uncrewed demonstration mission in December, which could have put Starliner in a position to launch astronauts in the first couple months of 2020 — if everything went according to plan.

But Starliner failed to light its engines at the correct moment after launch, throwing it off its planned path toward the ISS. Boeing and NASA decided to bring the vehicle back home, and it landed in the desert of New Mexico two days later.

The spacecraft was able to demonstrate a safe return. But it didn't dock with the space station.

It's not yet clear if NASA will require Boeing to repeat the mission or how long it will take to pinpoint the problem. But the space agency is still hopeful the vehicle will be cleared to fly humans in 2020.

Three astronauts have been selected to join Starliner's first crewed launch: NASA's Mike Fincke and Nicole Mann, as well as Chris Ferguson, a retired NASA astronaut who led the final 2011 Space Shuttle mission. Ferguson will fly as a commercial astronaut on behalf of Boeing.

NASA astronauts can come from a range of backgrounds, but test pilots are slated to fly on SpaceX's and Boeing's first crewed missions because they have the training to manually take control of the vehicles in case the automated systems fail during flight.

Though the US space agency paid the companies to develop their vehicles, Starliner and Crew Dragon are privately owned and operated. So, unlike previous human spaceflight programs, NASA will essentially be a customer for the companies.

SpaceShipTwo

British serial entrepreneur Richard Branson founded Virgin Galactic (SPCE) in 2004, and the company has been working ever since to develop a space plane capable of taking paying customers on brief flights to suborbital space.

Galactic is now in the final testing stages before it's ready to let customers on board. It expects to submit final paperwork to federal regulators "during the first half of 2020," according to public filings.

About 600 people have already reserved seats aboard Galactic's launch vehicle, SpaceShipTwo, for about $200,000 to $250,000 a piece.

SpaceShipTwo will take off like an airplane attached to a mothership and climb to 40,000 feet. The rocket-powered plane will then detach and fire up its engine, swooping upward to more than 50 miles above ground, a boundary considered by the US government to mark the beginning of outer space.

Passengers will experience a few minutes of weightlessness and scenic views before the descent. The full trip will last about an hour.

SpaceShipTwo requires two pilots to fly, and so far five Galactic crew members have already earned commercial astronaut wings from the US government for reaching space during test flights.

New Shepard

Blue Origin, the stealthy company founded by Amazon's billionaire founder Jeff Bezos, has been testing a rocket and spacecraft system for suborbital space tourism flights since 2015.

New Shepard is fully autonomous, and it completed its 12th uncrewed test flight last month. CEO Bob Smith told CNBC in a recent interview that tourism flights will "probably" start in 2020.

Unlike Galactic's SpaceShipTwo, New Shepard passengers will ride in a capsule that will take off atop a vertically launched rocket. It'll jolt up to more than 60 miles high, past the internationally recognized boundary of space — the Kármán line.

The New Shepard capsule detaches from the rocket near the top of its flight path. Future passengers will be able to experience a few minutes of weightlessness and panoramic views, and the capsule will deploy parachutes during descent to brake its landing.

Test flights have lasted just over 10 minutes from takeoff to landing.

It's not yet clear how much New Shepard flights will cost passengers; Blue Origin has not started selling tickets.

Rocket launches and space tourism account for a tiny sliver of the overall space economy, and NASA continues to conduct numerous robotic exploration and Earth science programs. But many are anticipating a surge in excitement once spacecraft start flying people from the United States once again.

That could accelerate the growth of an already booming commercial sector.

Wall Street banks, from Goldman Sachs to Morgan Stanley, predict the global space industry will grow to $1 trillion or more over the next two decades.

"Private sector investment has surged, and government funding is expected to increase significantly over the next decade," according to UBS.