In news Recently, a six person crew on Virgin Galactic’s VSS Unity spaceship undertook a brief trip to the “edge of space” which is known as Suborbital Flight.
Sirisha Bandla, an astronaut born in India, was a part of the crew. She was the third woman of Indian origin to go to space after Kalpana Chawla and Sunita Williams.
Virgin Galactic is a British-American spaceflight company, operating in the USA.
What is Suborbital Flight/Trajectory?
An object traveling above atmosphere at a horizontal speed of ~28,000 km/hr (orbital velocity or escape velocity) or more goes into orbit around the earth
Such a satellite would be accelerating towards the Earth due to gravity, but its horizontal movement is fast enough to offset the downward motion so that it moves along a circular path.
Any object travelling slower than 28,000 km/hr must eventually return to Earth.
Any object that launches to space but does reach sufficient horizontal velocity to stay in space falls back to Earth. This is known as flying in a suborbital trajectory.
It means that while these vehicles will cross the ill-defined boundary of space & atmosphere (known by Karman Line), they will not be going fast enough to stay in space once they get there & thus fall back to earth (see the projector in the figure below)
What is the significance of Suborbital Flights?
Increased Access for design innovation and experimental manipulation due to high projected flight rates.
They would be far less expensive than carrying experiments and people to the International Space Station. Helpful for microgravity research.
They could also be an alternative to parabolic flights in aeroplanes that space agencies currently use to simulate zero gravity.
