London to Sydney in 2 hours: space journey and ticket cost explained - how long does it currently take?

In 10 years time, passengers may be able to travel between London and Sydney, cutting through space on a suborbital flight to shave hours off current flight times.

The current length of a traditional flight between London and Sydney is approximately 20-22 hours, including layovers and stopovers. This involves a long-haul journey with multiple segments, typically involving a transfer at a hub airport such as Dubai or Singapore.

But a suborbital flight - which involves launching a spacecraft or a vehicle to altitudes above the Kármán line, internationally recognised as the boundary of space - could get you there in as little as two hours.

This isn't just a flight of fancy either, and medical research on the impacts of suborbital space flights is being funded by the UK Civil Aviation Authority (CAA).

Currently, suborbital flights like those provided by Richard Branson's Virgin Galactic cost more than £350,000 per seat, but the industry is actively working on improving safety, affordability and reliability to make them more accessible to a broader range of people.

What are suborbital flights?

Suborbital flights are a type of spaceflight that reach the edge of space without achieving a full orbit around the Earth. These flights typically involve launching a spacecraft or a vehicle to altitudes above 100 kilometres (62 miles), which is known as the Kármán line, internationally recognised as the boundary of space.

Suborbital flights have the potential to significantly reduce travel times between continents. Since the vehicles reach speeds of several thousand kilometres per hour, they could enable journeys from one side of the world to the other in a matter of hours. This would be a major advancement compared to current long-haul flights, which can take more than 10-15 hours.

The flights would also offer individuals the opportunity to experience weightlessness and see the Earth from a unique vantage point. Passengers would be able to enjoy the sensation of being in space for a short duration, and then return to Earth.

Though the propulsion systems used in suborbital flights, such as rocket engines, typically rely on the combustion of fossil fuels, which release carbon dioxide (CO2) and other greenhouse gases into the atmosphere, they have shorter durations and carry fewer passengers compared to long-haul commercial flights, which can help mitigate their carbon footprint on a per-passenger basis.

As suborbital flights become more prevalent, there is a potential increase in space debris, a growing problem caused by spacecraft and rocket stages that are not properly controlled or disposed of, and one which poses risks to other satellites, the International Space Station and future space missions.

What does the research say?

The majority of participants who took part in the CAA-funded study handled the G-forces of suborbital space journeys well, The Sunday Times reports.

Suborbital flights involve high speeds and changes in velocity, which can subject passengers to significant acceleration forces, commonly referred to as G-forces. The duration of high G-forces during a suborbital flight would be relatively short-lived, typically lasting for a few minutes during the ascent and descent phases.

It would be easy to assume that while the majority of healthy individuals should be able to tolerate the G-forces experienced during suborbital flights, people with certain medical conditions or physical limitations may need to consult with their healthcare providers to assess their suitability for such flights.

But the research, conducted with King's College London and supported by the RAF, suggests that those taking such journeys would not need to be in shape or young. Older individuals may actually be better at handling space travel, as they tend to have slightly "stiffer arteries," which would minimise the pooling of blood away from the brain.