For the second time in just over a year, SpaceX has sent a humanoid mannequin on a wild adventure into the heavens.

The humanoid — what NASA officially calls an "anthropomorphic test dummy" or ADT — was part of the private space company's successful docking of the Crew Dragon spacecraft on the International Space Station (ISS). And if the ADT could talk, what a story he'd have to tell.

The ADT wasn't just along for the ride; it was loaded with feedback sensors to help researchers analyze the flight's impact on future human astronauts. Hans Koenigsmann, vice president of Build and Flight Reliability at SpaceX, told reporters before the launch, "we'll measure the responses on the human body, obviously, and measure the environment. We want to make sure that everything is perfect for, you know, the safety of the astronauts."

In fact, that's why this docking mission was so important. It was the defining hurdle as SpaceX and other private companies take the reins of ferrying humans back and forth from the ISS — and beyond.

You can watch the launch ...

... and the successful docking in these two videos.

It's a big transition for the U.S. space program.

'Starman' isn't just along for the ride

SpaceX's original 'Starman' in space, after being launched aboard the company's Falcon Heavy in a Tesla Roadster in Feb. 2018.
SpaceX's original 'Starman' in space, after being launched aboard the company's Falcon Heavy in a Tesla Roadster in February 2018. (Photo: SpaceX)

In February 2018, SpaceX made history with the launch of its Falcon Heavy rocket, presently the world's most powerful operational launch vehicle. To test the payload capabilities, SpaceX CEO Elon Musk famously included his original cherry red Tesla Roadster.

"Test flights of new rockets usually contain mass simulators in the form of concrete or steel blocks," he wrote in an Instagram post. "That seemed extremely boring. Of course, anything boring is terrible, especially companies, so we decided to send something unusual, something that made us feel."

After the successful launch of the Falcon Heavy, the humanoid mannequin nicknamed "Starman" was revealed riding in the driver's seat and clad in the company's official spacesuit. As of March 5, 2019, the roadster and its famous passenger are 226,792,510 miles from Earth, or just beyond the orbit of Mars.

SpaceX's Crew Dragon capsule.
SpaceX's Crew Dragon capsule next to a Falcon 9 rocket. (Photo: SpaceX/Flickr)

Measuring 27 feet tall and 12 feet wide, SpaceX's Crew Dragon is a manned successor to the company's successful Dragon cargo spacecraft. In development since 2010, when NASA first announced it was seeking replacements for its Shuttle fleet, the Dragon capsule is capable of carrying up to seven astronauts. Unlike the space shuttle, this spacecraft features a launch escape system, with four side-mounted thruster pods capable of accelerating the craft in the event of an emergency from 0 to 100 mph in 1.2 seconds. You can watch a 2015 abort pad test of this escape system here.

As shown in the video below, the spacecraft is also designed to be comfortable, with several computer screens, large windows, and other amenities for the ride into space.

The success of either the Crew Dragon or its competitor, Boeing's CST-100 Starliner spacecraft, is critical to NASA's bottom line and to it's goal of severing its dependency on Russia's Soyuz spacecraft.

While a single seat on Soyuz presently costs $81 million, a comparable seat on either Dragon or Starliner is expected to cost "only" $58 million.

The astronaut access bridge to SpaceX's Crew Dragon spacecraft.
The astronaut access bridge to SpaceX's Crew Dragon spacecraft. (Photo: SpaceX/Flickr)

SpaceX's Crew Dragon set off on March 2 from Pad 39A of NASA's Kennedy Space Center in Cape Canaveral, Florida.

An artist's illustration of the SpaceX Crew Dragon docking with the International Space Station
An artist's illustration of the SpaceX Crew Dragon docking with the International Space Station. (Photo: SpaceX)

After the successful launch, the Crew Dragon separated from the Falcon 9 and began its roughly day-long journey to the ISS. Unlike previous SpaceX Dragon cargo missions, which utilized the ISS's robotic arm to achieve berth, the Crew Dragon used its advanced technology to perform an autonomous docking maneuver with the space station. NASA broadcast this critical part of the mission live on March 3. As you can see in the video, the welcome ceremony marked the opening of the hatch — as well as the retrieval of roughly 400 pounds of cargo onboard.

SpaceX Demonstration Mission 1 at Cape Canaveral's landing pad 39A
SpaceX Demonstration Mission 1, as it's called, at Cape Canaveral's landing pad 39A. (Photo: SpaceX/Flickr)

The Crew Dragon is scheduled to remain attached to the ISS until March 8 at 2:30 a.m. EST. After a visual inspection of the capsule lasting some five hours, the spacecraft will deorbit and reenter Earth's atmosphere. While the Crew Dragon at one point was designed to include landing thrusters, the unit will instead splashdown in the Pacific via four parachutes.

"SpaceX is required to get the crew and spacecraft out of the water in less than an hour after splashdown," NASA said in a press release.

The successful completed mission will help pave the way for both an ascent abort test (scheduled for June) of the Crew Dragon's launch escape system and a manned mission sometime in July.

"Human spaceflight is basically the core mission of SpaceX," Koenigsmann added in a preflight briefing. "So we are really excited to do this. There's nothing more important for us than this endeavor."

Editor's note: This story has been updated since it was originally published in February 2019.

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.