Say you’re headed on a weekend beach trip and you see one of your tires is worn down. You know you have a spare. No worries. But earlier that day, your wife/husband/partner/buddy finds the spare went flat. Now, he or she believes the tires on the car look just fine. The two of you don’t talk, because, well, you both gotta pack. Will the two of you make it to the beach, or not?

That scenario is called "accretion of risk"—two decisions that seem fine independently, but put together result in a bigger chance of something going wrong in the future. And according to a new report from an independent safety panel, it might be happening right now at NASA as the agency prepares to launch humans beyond Earth and the International Space Station in the early 2020s.

The cause of this rolling increase in risk? Pressure to contain costs and keep to two different launch schedules. “Does one hand know what the other is doing?” asked James Bagian, a former astronaut, professor of engineering and medicine at the University of Michigan, and member of the panel that wrote the report. “If everyone doesn’t understand all the assumptions, and they use that as a foundation to make a decision, that can have a ripple effect.”

In its report, a yearly exercise, the six-member Aerospace Safety Advisory Panel concluded that the space agency managers and engineers are making decisions without talking to all the relevant parties. “Over the past year, the Panel has noted a continuing and unacknowledged accretion of risk in space flight programs that we believe has the potential to significantly impact crew safety and the safe execution of human space missions,” the panel concluded. Specifically, they worried that NASA isn't doing enough full-flight testing of heat shields, crew abort pods and other components of the new Orion rocket.

Now, flying to outer space is risky business no matter what precautions you take. And these human spaceflights won’t occur until 2021, or 2023, depending on which of NASA’s schedules wins out. A test flight goes up in 2018. That's enough time that NASA spokesman Grey Hautaluoma says the agency will worry about it later. “Some questions about risk acceptance will need to be addressed when our commercial partners are closer to actually flying humans to space,” he said in an e-mail statement. “Others may need to be addressed by the appropriate federal regulatory agencies, once our partners are ready to fly. The agency is absolutely committed to safe flight of our astronauts aboard commercial vehicles and continuing to lead the world in exploration and human spaceflight.”

Bagian, who flew missions on the space shuttle in 1989 and 1991, says that behind that commitment, something even worrisome is going on. Managers aren't communicating consistently to each other the risks they're taking. NASA is making safety decisions by committee instead of individual managers taking responsibility. As far back as the 1986 Challenger investigation, safety panels have been recommending NASA leaders clearly state who is making decisions to accept risk.

Nobody wants another launch or re-entry failure. But does NASA have enough institutional memory to avoid the mistakes of the past? So far, NASA has ignored the recommendations of his panel, Bagian says. "NASA is more than welcome to say, 'we disagree,'" Bagian says. “Our concern is that it’s been a year, and they haven’t responded.”

On Thursday, NASA announced it was choosing not one, but three commercial companies to launch cargo ships to the International Space Station between 2019 and 2024. SpaceX, Orbital/ATK, and Sierra Nevada are all on tap for six flights each to the ISS. That's essentially the entire industry.

But SpaceX and Orbital and both recovering from launch failures in the past year. Sierra Nevada’s DreamCatcher space plane hasn’t flown yet. More spaceships mean more risk managers and more decisions. On the other hand, they also mean a more spread-out portfolio. “If you lose one you have the ability to have one go up right after it,” said Kirk Shireman, NASA’s ISS manager, upon announcing the contracts. That’s a big help to us. All of these vehicles have different capabilities.”

With luck, all those missions will let NASA learn to move fast and still minimize risk. The agency says it'll be focusing on safety with the companies when work starts with them later this year. Nobody wants to get a flat on the way to the beach—especially when the beach is on Mars.