Supersonic travel? That's so 2021.
While companies like Boom Supersonic and Lockheed Martin are investing in technology that would bring back commercial supersonic travel, a handful of startups are looking beyond the speed of sound to hypersonic travel, promising 90-minute flights from New York to London.
Though the definition of hypersonic isn't set in stone, the term generally refers to an aircraft that can fly at Mach 5, or five times the speed of sound. That translates to about 3,900 miles per hour, or a two-hour trip across the Atlantic. The supersonic Concorde, by comparison, flew at Mach 2.02, taking it from New York to London in three and a half hours.
While aircraft capable of safely carrying people at hypersonic speeds is likely at least a decade away, venture capital firms are pouring hundreds of millions of dollars into startups like Hermeus and Venus Aerospace. To learn more about their aircraft and visions for the future of travel, watch the video above.
There are a host of challenges these companies must solve to make hypersonic flight a reality. They'll need to build engines that not only can accelerate a vehicle to hypersonic speeds but also can maintain those speeds efficiently. They'll also need to design aircraft that can withstand the intense heat generated from friction and air resistance during hypersonic travel.
Humans have traveled at hypersonic speeds before. In the 1960s,flew faster than Mach 5 several times, peaking at Mach 6.7 (about 5,140 mph). Astronauts aboard NASA's now-retired space shuttles would hit hypersonic speeds during reentry.