As competition in the space tourism industry heats up, a US-based firm said Friday it was excited to re-enter the sector with the upcoming launch of a Japanese billionaire.

Space Adventures, headed by Tom Shelley, is set in December to send Japanese tycoon Yusaku Maezawa to the International Space Station (ISS) from the Russia-leased Baikonur Cosmodrome in Kazakhstan.

It's the company's first launch in over a decade after suspending trips to the ISS as NASA bought up seats on Russia-operated flights and no other vehicles were available.

"It's a very exciting time for us," Shelley, 48, the president of Space Adventures, told AFP during an interview in Moscow on Friday.

He added that Space Adventures with Russia was planning future launches "to innovate and find new offerings" for clients.

Asteroids are remnants of the early Solar System, with the potential to reveal secrets of our planet's origins. But they could also bring an end to life on Earth. Now two missions, Lucy and DART (Double Asteroid Redirection Test) will provide further insights into both of these features—with DART even attempting to redirect the orbit of a moon around an asteroid.

Space rocks are generally considered to be asteroids if they are larger than approximately 1km in size, and made principally of "non-volatile" materials—chemicals that can be easily vaporized. Carbon monoxide, for example, is volatile as it vaporizes at a temperature of -191°C. But iron, with a vaporization point of 2,862°C is non-volatile.

This is somewhat different to comets. Asteroids are found more commonly in the inner Solar System, whereas comets with their volatile-rich composition tend to lurk in the outer part, far from the heat of the Sun.