If a space tourism flight goes horribly wrong, it could be even harder to rescue passengers than the Titan sub disaster

• Risky tourism to the edges of the Earth and beyond is becoming more common.
• Rescue efforts for the Titan submersible, led by the US Coast Guard, may have cost millions.

The multi-day search and rescue mission for the Titan, which ultimately ended after debris from the submersible was found, showed just how challenging — and expensive — trying to save people from the deep ocean can be.

But if a commercial space expedition ends up in trouble, the logistics of a rescue mission could be even murkier.

The submersible experienced a catastrophic implosion while carrying tourists to the Titanic shipwreck at the bottom of the Atlantic Ocean, killing everyone on board. Its fate, and the unsuccessful rescue operation involved, now has explorers looking fearfully to the skies.

Accessing space poses its own set of unique challenges, not least of which is safely transporting people to an environment that is otherwise incompatible with human life.

But tourism expeditions to space are on the rise: Jeff Bezos' Blue Origin and Richard Branson's Virgin Galactic have launched paying passengers to the edge of space, while SpaceX is sending tourists all the way into orbit.

Fortunately, they've all gone according to plan. But what happens if disaster strikes?

"How rescue should be managed for commercial flights remains unclear," Leroy Chiao, a retired NASA astronaut and International Space Station commander, said in an op-ed for CNN.

Chiao continued: "There are, however, the same uncomfortable questions that were raised in discussion about rescuing a submersible from the ocean floor: What is the plan if the spacecraft loses the ability to come home on its own? Who will foot the cost for a space rescue if something goes awry? Should taxpayers be expected to cover all or most of the expense?"

NASA used to have rescue missions ready-to-go

Chiao, who also served on SpaceX's Safety Advisory Panel, the NASA Advisory Council, and the White House Review of Human Spaceflight Plans Committee, said one of the hardest parts of extreme travel is crew rescue.

After the Space Shuttle Columbia disaster in 2003, NASA adopted a new protocol in case there was a need for rescue.

On January 16, 2003, Columbia launched for its 28th and final flight. During the launch, a piece of foam broke off and struck the shuttle's left wing, but the extent of the damage was not fully known. On February 1, when Columbia attempted to make reentry into the Earth's atmosphere, it disintegrated, leading to the deaths of all seven astronauts on board.

It would be two years before another NASA space shuttle was sent to space. The agency implemented "Launch on Need" missions, which were fully assembled and ready to fly to rescue crew from a space shuttle that was no longer able to successfully return to Earth, like in the case of Columbia.

By the time the space shuttle program ended in 2011, none of the contingency missions had ever been needed. NASA now relies on the Russian Soyuz spacecraft or private entities, like SpaceX's Crew Dragon, to get astronauts to space.

How to get 'stuck' in space

Chiao explained to Insider that a scenario in which a spacecraft could be "stuck" in space — or unable to return home — is really only relevant for orbital flights.

Unlike SpaceX, Blue Origin and Virgin Galactic currently only offer suborbital flights — meaning the space crafts are not going fast enough to enter orbit.

"In the case of suborbital flight, it's very different. The trajectory is an arc. You're going up like a cannonball and you're going to fall back down," Chiao said, adding, "they're not going to get stuck in space."

Orbital flights could end up stranded in space, but the International Space Station does help prevent that.

Typically, orbital flights are launched directly to the ISS, or at least into the same orbital plane — the imaginary flat surface extending from the Earth along which the ISS travels — so that if needed they could maneuver and dock at the station, using it as a safe haven until they could be rescued.

"But if they launch into a different orbital plane, they're on their own," Chiao said. "That means if they have a problem, and they can't get back down on their own, then they're just going to keep orbiting the earth and they're kind of done for."

He said SpaceX, which transports NASA astronauts and paying tourists into orbit, would most likely always launch to the ISS or at least into the same orbital plane.

However, if they had some kind of guidance or navigation problem, they could end up in the wrong plane. And they could simply choose to launch into a different orbital plane, for instance, if it allowed them to use less fuel, but Chiao said it's highly unlikely they would take that risk.

It's also worth noting that because SpaceX works with NASA, its spacecraft have to pass the agency's safety standards, unlike the suborbital offerings of Blue Origin and Virgin Galactic which are not independently certified.

It's unclear what would happen if a rescue is needed

SpaceX does not have a "Launch on Need" rescue ready for each of its missions, and instead depends on the ISS as a safe haven as their contingency plan, according to Chiao. But even if a spacecraft that could no longer re-enter Earth's atmosphere was able to temporarily dock at the ISS, another spacecraft would be needed to retrieve the crew members and bring them home.

"There's not necessarily another spacecraft ready to go," Chiao said.

And a space flight isn't exactly something that can be thrown together overnight. There's also a question of who would organize or pay for it.

"Presumably if it's a SpaceX vehicle that got them up there, SpaceX would be on the hook to launch another vehicle to go rescue them," Chiao said. "Why would NASA have to pay for it?"

On Earth, the Coast Guard does not charge for rescues it performs in US waters, including the search effort for the Titan submersible, which was estimated to have cost millions of dollars. But space doesn't have a Coast Guard equivalent. There's no national territories or agencies operating in space that would automatically take the reigns.

But with more and more companies launching tourists into space, questions about who would step in to help if a rescue was needed are only going to become more relevant.

Blue Origin, Virgin Galactic, and SpaceX did not respond to Insider's requests for comment.