The latest news: SpaceX conducted a static test fire of the Crew Dragon's abort engines on April 20, all part of the planned sub-orbital abort test scheduled for June. During the last in a series of tests, the spacecraft experienced what was described by the company as an "anomaly," with a large plume of orange smoke visible for miles from the Kennedy Center launch pad.

"Ensuring that our systems meet rigorous safety standards and detecting anomalies like this prior to flight are the main reasons why we test," SpaceX said in a statement. "Our teams are investigating and working closely with our NASA partners."

Leaked footage reported to be of the test, shown below, indicates that the anomaly encountered by the Crew Dragon –– the same that successfully docked with the International Space Station in March –– was nothing short of catastrophic.

With the Demo-1 Crew Dragon now destroyed, it's unclear whether SpaceX will be able to ready a substitute for its planned June abort test. More likely is the unfortunate possibility that the company's Crew Dragon mission will be delayed indefinitely pending an investigation into what caused the explosion. Thankfully, no one was hurt in Saturday's test fire and whatever engineering lessons are learned from this failure will improve the safety of future Crew Dragon spacecraft.

"This accident should offer a clarifying moment for SpaceX and Musk that it really must get commercial crew right — and that putting humans on a Falcon 9 rocket, inside a Dragon spacecraft, raises the stakes," writes Eric Berger for ArsTechnica. "This is not easy. It is very hard."

We'll add more information here as the story unfolds. What follows is our original article about SpaceX's summer 2019 efforts to launch astronauts to the ISS.

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After years of development and testing, SpaceX's Crew Dragon spacecraft may soon be ready to welcome its first human passengers.

The private aerospace company, fresh off the first commercial launch of its Falcon Heavy rocket, is closing in on the race to bring human spaceflight home for NASA. In March, SpaceX's Crew Dragon completed a crucial demonstration mission (Demo-1) to the International Space Station that pushed the company ever closer to expanding beyond its commercial launch capabilities.

"The whole goal of SpaceX was crewed spaceflight. Improved space exploration technologies," CEO and founder Elon Musk said earlier this year. "That's actually the full name of the company, Space Exploration Technologies."

While NASA astronauts Bob Behnken and Doug Hurley are already training and familiarizing themselves with Crew Dragon, there's still work to be done before the historic launch can be scheduled. Below are just a few highlights of the fine tuning under way by SpaceX is preparation for what may be a summer launch to the ISS.

Sub-orbital flight abort test: June 2019

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)

While not specifically required by NASA, SpaceX in June will reuse the Crew Dragon from the Demo-1 mission for a test of its in-flight abort system. This advanced escape system, a feature lacking in NASA's shuttle spacecraft, uses four side-mounted thruster pods to accelerate Crew Dragon 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 in the video below.

For the June test, SpaceX will launch the Crew Dragon aboard a Falcon 9 rocket into sub-orbital space. Unlike traditional launches, this Falcon 9 will be pre-configured to shutdown and terminate thrust at Max Q, the point at which the vehicle experiences maximum aerodynamic pressure. The Crew Dragon will autonomously detect this error and launch its abort sequence.

"Dragon would fly until SuperDraco burnout and then coast until reaching apogee, at which point the trunk would be jettisoned," the company stated in a draft environmental assessment to the Federal Aviation Administration last fall. "Draco thrusters would be used to reorient Dragon to entry attitude. Dragon would descend back toward Earth and initiate the drogue parachute deployment sequence at approximately 6 miles altitude and main parachute deployment at approximately 1 mile altitude."

Control and life support

Commercial Crew Astronauts Doug Hurley and Bob Behnken inside SpaceX’s Crew Dragon
Commercial crew astronauts Doug Hurley and Bob Behnken perform prelaunch and launch activities inside SpaceX's Crew Dragon. (Photo: SciNews/YouTube)

Because the Demo-1 mission carried only cargo and a sensor-loaded humanoid named Ripley, SpaceX elected to forego including the full life support system that will be featured in its crewed launch. That said, the air revitalization equipment –– critical for regulating oxygen and carbon dioxide inside the spaceship –– performed flawlessly.

While Demo-1 performed many of its tasks autonomously, Demo-2 will have humans on board to either override or manually control the craft. To that end, SpaceX is also working on perfecting the touch-based software and various monitors that were disabled for the original test flight.

"Being able to fly the first flight of a vehicle as a test pilot is a once-a-generational type of opportunity," astronaut Doug Hurley, who has been training on a SpaceX Dragon Crew simulator, said last year. "But I would also say that we have a lot of work left to do, and we are in it for the long haul to make this vehicle as great as possible for our friends back in the astronaut office, that maybe haven’t even gotten hired yet, but they’re going to fly on this vehicle someday. We take that job very seriously."

As an additional sign that human spaceflight is coming to Dragon, SpaceX also confirmed that a toilet feature will be added in the Demo-2 iteration.

One more thing...

The uncrewed SpaceX Crew Dragon spacecraft became the first Commercial Crew vehicle to visit the International Space Station in March 2019.
The unmanned SpaceX Crew Dragon spacecraft became the first commercial crew vehicle to visit the International Space Station in March 2019. (Photo: NASA/Wikimedia Commons)

According to SpaceX, another feature on the Crew Dragon that will receive an upgrade is the unit's Draco thrusters. During testing, the team found that extended periods of exposure to the deep freeze of space could possibly damage the thruster's propellant lines.

With Crew Dragon designed to stay docked to the ISS for as long as 210 days, the Demo-2 unit will now feature integrated heaters on the propellant lines.

SpaceX's Crew Dragon spacecraft as shown during an unveiling in May 2014.
SpaceX's Crew Dragon spacecraft as shown during an unveiling in May 2014. (Photo: SpaceX/Flickr)

With the above tweaks, additions and tests, Crew Dragon could be ready for its historic mission to the ISS as soon as later this summer. No small feat, it would mark the first crewed flight of an American spacecraft into orbit since the Space Shuttle Atlantis in July 2011.

"[This] is a very significant step that marks opening up of low-Earth orbit to commercial companies, not only to (carry) NASA (astronauts) but perhaps other customers," space station astronaut Anne McClain told CBS News of the Demo-1 launch in March. "This is a model where NASA is one customer of many, and so I think the possibilities are endless ... for science, research and commercial companies."

Editor's note: This story has been updated with new information since it was first published in April 2019.

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