Human spaceflight — orbital, suborbital and beyond — will be key to the growth of the space industry in the coming years.

Why it matters: Right now, most revenue in the space industry is tied up in government contracts, but experts say the maturing industry will need tourism to grow into the $1 trillion economy some predict it could be.

• Tourism ventures may not bring in huge amounts of revenue when compared to the rest of the industry, but they could bolster it as a whole, bringing in new talent and making space something the public thinks about daily.

Driving the news: Two space tourism companies — Virgin Galactic and Blue Origin — are expected to fly passengers to suborbital space this year.

• Virgin Galactic's stock has been rallying, though what's fueling interest in the company isn't yet clear.
• SpaceX just penned a deal with Space Adventures to fly private citizens to orbit aboard its Crew Dragon spacecraft next year.
• Northern Sky Research predicts the suborbital and orbital tourism market could be worth as much as $14 billion in revenue worldwide by 2028.

Details: NASA funded the development of SpaceX and Boeing's crewed systems, and now other companies are hoping to make use of them to fuel their own businesses.

• Axiom Space, which plans to build the first commercial space station, wants to use both companies to fly its own astronauts and even private tourists to orbit.
• Bigelow — a company that plans to build private, inflatable space stations — has already expressed interest in sending people to the International Space Station using SpaceX capsules.
• NASA hopes these kinds of collaborations will foster a robust economy in low-Earth orbit in order to transition the space agency into becoming a buyer of services instead of a provider.

Yes, but: The market for suborbital tourism and especially orbital tourism will likely be limited to just the most wealthy people on Earth, at least for the immediate future.

• There are also real questions about how long suborbital tourism will hold the public's interest.
• Orbital tourism is millions of dollars more expensive than a suborbital trip to space, and it likely won't get much cheaper in the near term, so if these suborbital space travelers get a taste for spaceflight, that may be as far as they can go.
• After an initial flurry of suborbital rides exhausts the market, people will be asking "What's next?" James Vedda of the Aerospace Corporation told Axios. "And then the next thing needs 10 more years of development. That gap is going to deflate the interest in the market."

Blue Origin and Virgin Galactic are the American front-runners in the race to launch tourist flights to the edge of space, but they're approaching it in two very different ways.

Details: Blue Origin — backed by Jeff Bezos — plans to use its New Shepard space system to launch customers to suborbital space in a capsule that separates from a small rocket and then comes back to Earth under parachutes.

• Virgin Galactic — founded by Richard Branson — relies on a space plane dropped from a carrier aircraft.
• Once dropped, the plane's rocket motor kicks on, bringing passengers high into the atmosphere.

By the numbers: Both Blue Origin and Virgin Galactic’s systems are designed to fly passengers more than 50 miles above the Earth’s surface.

• Virgin Galactic's seats are about $250,000 a pop with more than 600 tickets sold to date. Blue Origin's tickets are expected to be comparable in price.
• Both will allow passengers to experience a few minutes of weightlessness before coming back to Earth.
• Blue Origin and Virgin Galactic will carry six passengers per flight, but while Virgin's system will have two pilots flying the space plane, Blue Origin's flies autonomously.

Virgin Galactic flew its first test passenger in 2019 and is expected to fly Branson sometime this year. Blue Origin has yet to launch a person with its space system.

Between the lines: The FAA is able to regulate the safety of the public under the launch licenses these companies need to fly their suborbital vehicles, but the government doesn't have the ability to regulate the safety of the systems themselves.

• Congress placed a moratorium on FAA rule-making around the safety and design of these vehicles until at least 2023, unless a major accident or close call occurs.
• Proponents of the moratorium say it is necessary to allow these companies to develop their systems and start flying before regulations that could stifle growth are put in place.
• Others think that these systems should be held to a high standard of safety, in similar ways to the airline industry today.

Mars shakes with quakes more often than scientists initially expected, according to a new series of studies using data from NASA's InSight lander published this week.

Why it matters: Mars looks like a cold, dead world, but its geology is complicated. The InSight lander, which has been studying the Red Planet from its surface since 2018, is giving scientists a more full picture of the rusty world.

Details: According to NASA, InSight has recorded more than 450 signals from seismic activity so far, with the largest quake measuring in at about 4.0 magnitude.

• At the end of 2019, InSight was, on average, measuring seismic signals twice per day, according to the agency.
• The new research shows two relatively strong marsquakes were tracked to the Cerberus Fossae region, where scientists found volcanic activity that may have been responsible for the shakes.

“If you just take a simple model of Mars, you wouldn’t expect it to be hot enough inside to be producing magma. So, what it says is that there’s probably some variability at depth that the source of which is not obvious at the surface.”

Be smart: Mars doesn’t have plate tectonics the way Earth does. Instead, these quakes are likely caused by volcanic regions shaking the world or the cooling and contracting of the planet itself.

The last company vying for a $12 million DARPA prize for launching rockets two times from two locations with little notice could stage its first flight as early as this week.

The big picture: DARPA's launch challenge is designed to simulate a real-life scenario that the military may require of its launch providers in the future.

• If, for example, the military needs immediate eyes on a part of Earth that can't be easily surveyed by other means, having this rapid-launch capability could mean getting a small satellite to orbit and in operation quickly to help.

Details: The company — named Astra — was originally aiming to launch its first rocket from Kodiak, Alaska, today, but bad weather in the area has pushed the attempt back.

• The launch window for the first attempt is open until Sunday, but depending on the weather, DARPA may extend that window.
• To win the full $12 million, the company will then need to launch a second rocket once the second launch window opens in mid-March from a different pad at the same launch site in Alaska.
• Originally, it was expected that DARPA would request that the company stage one launch from Alaska and the other from another launch facility, but concerns over logistics caused the agency to pick two different launch pads at the same site instead.

Between the lines: Astra isn't hanging its hopes on winning the DARPA challenge to make its business successful. CEO Chris Kemp told Axios that Astra doesn't expect its first launch will get a satellite to orbit.

• The company instead sees the launch series as a way of testing its rocket and changing things as needed.
• "We're not aiming for perfection," Kemp told Axios earlier this month. "We're aiming for overall economics that we can offer our customers and offer our shareholders."
• Astra plans to focus on launching small satellites whose operators are looking for a deal on getting into space more cheaply than other options.

Go deeper: You can watch the launch webcast live through DARPA.

Astronomy expands its scope from the heavens to humans (Sarah Scoles, Wired)

From Dubai to Mars, with stops in Colorado and Japan (Kenneth Chang, New York Times)

Elon Musk wants to build a private "SpaceX Village" (Dave Mosher, Business Insider)

NASA mathematician Katherine Johnson, depicted in "Hidden Figures," dies at 101 (Marisa Fernandez, Axios)

A large cluster of stars 19,000 light-years from Earth harbors something strange: Within the cluster, a neutron star left over after a supernova explosion orbits a star not too different from our Sun.

• The Chandra observatory has been observing that star system — known as Terzan 5 CX1 — for more than a decade, and in that time, Terzan 5 CX1 has gone from looking like one type of star system to another and back again.
• As that neutron star orbits the other in the pair, its immense gravity pulls material from the companion star, forming a disk around the neutron star.
• All that material falling in on the neutron star makes it spin quickly, blowing away any extra material encircling the star and transforming it into what's known as a millisecond pulsar.

Yes, but: Chandra found this star system has gone from behaving like a more typical binary to a millisecond pulsar and then back again.

• It's not yet clear why the pair has done this dance multiple times, but scientists expect this is a phase in the evolution of these types of star systems.