KENNEDY SPACE CENTER, Fla. — The Securities and Exchange Commission is all over him. The Air Force inspector general is auditing his launch certifications. And even NASA, one of his most ardent supporters, is reviewing the safety culture at SpaceX after Elon Musk smoked a joint on a podcast.

If that weren’t enough pressure, the billionaire entrepreneur is facing one of the most crucial moments in SpaceX’s history early Saturday, when the spacecraft designed to carry humans is scheduled to lift off from a storied launch site here.

Although the Dragon spacecraft won’t be carrying astronauts — only a mannequin named “Ripley” with sensors and about 400 pounds of cargo — the flight will mark a significant step toward the restoration of human spaceflight from U.S. soil since the space shuttle was retired nearly eight years ago.

The heat isn’t just on SpaceX and Musk, who has drawn scrutiny from the SEC over his leadership of his electric car company, Tesla, but on NASA, as well. Years ago, it placed a bold bet on the private sector and outsourced human spaceflight to the International Space Station to two companies: SpaceX and Boeing. The companies won the contracts, worth a combined $6.8 billion, in 2014.

Since then, both companies have faced setbacks and delays as they struggled to meet NASA’s rigorous safety requirements. But now NASA says they are poised at long last to make their first flights with humans this year — a timeline many in the industry believe may be optimistic given the immense challenge.

Since the space shuttle retired in 2011, NASA has had to purchase seats on a Russian spacecraft, the Soyuz. Those seats runs out by the end of this year, so if SpaceX and Boeing’s spacecraft are not ready, NASA would have to purchase additional seats or face the prospect of not having an American astronaut on board the space station, in which the United States has invested about $100 billion.

With so much at stake, SpaceX’s launch, scheduled for 2:49 a.m. Saturday, “is an absolutely critical first step,” William Gerstenmaier, NASA’s associate administrator for Human Exploration and Operations, said during a news briefing last week.

For SpaceX, a successful flight would mark a crucial next step in its quest to make routine human spaceflight possible. And it would be another triumph for a company that improbably upended the launch industry by pulling off such feats as landing and reusing rocket boosters, usually discarded after each use.

A failure, however, would be devastating. Two SpaceX rockets have exploded: one in 2015 while flying cargo to the space station and another on the launchpad in 2016 ahead of an engine test fire. The company has bounced back from those failures and flown nearly 70 successful missions. But recently the Air Force inspector general announced it is reviewing the certifications granted to SpaceX that allow the company to fly national security missions, a key source of revenue.

NASA officials said that although they are confident about the flight, and have signed off on it after multiple flight reviews, SpaceX must still address several technical issues before flying people later this year.

SpaceX also said it is ready. The company has done “an incredible amount of testing to make sure that everything is safe and ready to go,” Hans Koenigsmann, SpaceX’s vice president for build and flight reliability, told reporters Thursday.

Still, the company has a lot of work to do before it flies humans, officials said.

NASA and SpaceX are still studying the pressure vessels inside the rocket’s second-stage fuel tank that led to an explosion in 2016, before an engine test firing. NASA’s Gerstenmaier said last week that the teams have completed a statistical analysis of the problem.

Now, he said, NASA and SpaceX are examining the “physics behind” the possible source of ignition when fibers around the tank break free and generate heat.

“So now we're going back and we're proving to ourselves that this breaking is so unlikely that it's not going to be a concern to cause the ignition event and cause the problem moving forward,” he said.

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Gerstenmaier said thrusters on the spacecraft can also "break free and liberate and come out” if they get too cold. He said that although the problem can be prevented by keeping the propellant “at a certain temperature,” SpaceX may need to redesign that part, as well.

He said finding technical challenges was a typical part of the testing process to see how the spacecraft operates and fix any problems before flying people.

Overall, he said the vehicle is in “very, very good shape."

“I’m very comfortable with where we’re headed with this flight. I fully expect we’re going to learn something on this flight. I guarantee you everything will not work exactly right. And that’s cool. ... We want to maximize our learning so we can get the stuff ready so when we put crew on, we’re ready to go do a real crew mission,” Gerstenmaier said.

SpaceX flies its Dragon spacecraft to deliver cargo and supplies to the station. During those missions, which don’t have people on board, the spacecraft sidles up to the station and is captured by a robotic arm operated by one of the astronauts aboard the station.

For this mission, the spacecraft will dock with the station autonomously, like a self-driving car pulling into a parking spot, except the space station travels at 17,500 mph in orbit, circling the globe every 90 minutes.

“We need to make sure that it can safely go rendezvous and dock with the space station and then undock safely and not pose a hazard to the International Space Station,” Kathy Lueders, NASA’s commercial crew program manager said last week.

NASA officials said last week that the Russians, who are partners on the station, raised a concern about SpaceX’s docking software. But it has since been resolved, officials said Thursday.

SpaceX designed its Dragon spacecraft, a sleek capsule with three windows that sits on top of the Falcon 9 rocket, with human flight in mind from the beginning. It is equipped with eight engines that allow it to fly away from the rocket in the case of an emergency — a capability the space shuttle did not have.

The mannequin on board for Saturday’s flight is named “Ripley,” for Ellen Ripley, the character in the movie “Alien” played by Sigourney Weaver. She is outfitted in a SpaceX space suit equipped with sensors to monitor the condition of the crew cabin and the forces that the flight puts on the body.

Safety is SpaceX’s top priority, company officials have repeatedly said. But when Musk was seen smoking marijuana on a podcast, it worried NASA’s leadership, which decided to conduct a safety review of both SpaceX and Boeing.

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“We need to show the American public that when we put an astronaut on a rocket, they’ll be safe,” NASA Administrator Jim Bridenstine said in an interview late last year.

SpaceX’s Falcon 9 rocket has been upgraded over the years to make it “the most reliable rocket ever built,” Musk said during a press call last year. I hope fate does not punish me for those words, but that is unequivocally the intent.”

Musk, who founded SpaceX in 2002 with the goal of ultimately sending humans to Mars, is well aware of the difficulties of space flight. “There could be a thousand things that could go right, and one thing that goes wrong,” he said. “The reason it is so hard to make an orbital rocket work is that your passing grade is 100 percent.”

Source:The Washington Post