• The company's unique flight profile hinges on its LauncherOne rocket mounted beneath the wing of an ex-Virgin Atlantic Boeing 747 jet.
• During a launch, the rocket is designed to drop from the wing and ignite its engine, lofting relatively small payloads to orbit from high altitude.
• This saves on fuel, since the rocket doesn't have to travel through the thickest parts of the atmosphere.

Driving the news: On Sunday, Virgin Orbit — which was spun off from Richard Branson's human spaceflight-focused Virgin Galactic — conducted another test flight of its "Cosmic Girl" plane. The company also flew another test flight last Thursday, and it's gearing up for more.

• The 2 tests over the last week were both "heavyweight" captive carry flights, meaning that LauncherOne was weighed down to simulate its expected heaviest weight at launch, but it never detached from the plane.
• "All the design is done, all of the parts have been manufactured, every bit has been tested as a bit, so there's no need to wait around," Virgin Orbit vice president of special projects Will Pomerantz told Axios. "We're all fired up, and ready not just for our first flight but to get into commercial operations. It's intense, but fun."

What's next: For now, Virgin Orbit is staying mum on when it's planning to fly the first full test flight.

• In the immediate future, the company will need to conduct a "drop test," where it drops the heavyweight rocket from the plane, letting it fall to test all its components without actually lighting up the rocket itself.
• Virgin Orbit also has plans to launch from Japan and the U.K. when it starts flying.
• The fact that its launcher is mobile allows it to operate in multiple countries.

Yes, but: While some experts have raised the concern that something of a "rocket bubble" is forming, Virgin Orbit is usually cited as a promising company in this space for its innovative launch mechanism.

• “Pristine or dynamically new comets are entirely uncharted and make compelling targets for close-range spacecraft exploration to better understand the diversity and evolution of comets,” Günther Hasinger, ESA’s director of science, said in a statement.

The big picture: Comets like these are thought to be preserved leftovers from the dawn of the solar system and could help unlock how Earth got its water.

Details: Comet Interceptor is designed to lie in wait in space until a pristine comet is spotted as it moves into the heart of the solar system.

• Once the target is set, the spacecraft — which is comprised of three modules that can separate from one another — will then move to map and study it.

One fun thing: Because of the mission design, it’s also possible that the spacecraft could intercept a visitor from outside the solar system.

• If scientists spot another interstellar asteroid or comet like Oumuamua — the asteroid from another solar system that shot through ours in 2017 — the spacecraft could target that object instead.

The backdrop: This won’t be ESA’s first mission to a comet. The space agency also studied Comet 67P from close range with its Rosetta spacecraft and Philae lander. That comet, however, is far from pristine, having flown toward the Sun many times.

• This only amounts to a tiny sliver of what could be studied.
• If you compare the volume of space we're able to search for signs of advanced technology to the volume of Earth's oceans, then "so far since 1960, we've searched about one hot tub's worth of the ocean," says longtime SETI researcher Jill Tarter.

Where it stands: The $100 million Breakthrough Listen project, founded by Russian billionaire Yuri Milner, launched in 2015.

• It is expected to survey 1 million stars, 100 nearby galaxies and the galactic plane for technosignatures that presumably only an advanced society could send into space.
• The entire project will last a decade.
• On June 18, Breakthrough Listen publicly released the data it has gathered so far in the largest dump of its kind.

The catch: Scanning the skies for radio signals from out there isn't easy. In order to pick up on whatever relatively faint signals might be emitted, scientists need to use sensitive radio telescopes on Earth to hear them.

• That might get harder in the future, however, as more large constellations of satellites are launched, making it even more difficult to listen for any faint signals.

Meanwhile, it's not a sure thing that we have the capability to hear the calls of an advanced alien civilization.

• "So there's always that possibility that we're just, you know, not at the point where we can pick up the signals easily. There may be lots and lots of signals, but we can't pick them up," SETI Institute's Seth Shostak told Axios.

The backdrop: It's also possible — in fact more likely — that scientists will find life in another way that has nothing to do with hunting for technosignatures.

• Last week, NASA's Curiosity rover sniffed out methane on Mars, which could be a tantalizing hint of microbial life currently on the red planet.
• Scientists also hope to one day search water-rich moons like Enceladus or Europa that might harbor microbial life today.
• NASA's next generation telescopes could give scientists a glimpse of distant planets that might have environments ripe for life.

What's next: There is an increase in SETI efforts around the U.S. and internationally.

• Breakthrough Listen, for its part, has a deal to eventually use China's huge FAST radio telescope and others to aid in the search.
• "I always think SETI is kind of a reflection on our own capabilities as a civilization, and the things we're able to look for are limited by the technology that we have," Breakthrough Listen scientist Danny Price told Axios.