Washington, Nov 26: Though the earth’s gravity prevents today’s standard aircraft out of space and keeps us anchored on the planet’s surface, there are still ways for aircraft- based vehicles to reach space.

NASA asserts that any vehicle hoping launch into orbit has to travel about seven miles per second (11 kps), or about 25,000 mph (40,000 kph) which a lot faster than an average sub-sonic airliner.

The shortest distance between Earth and space is about 62 miles (100 kilometers) straight up, which by general accord is where the planet's boundary ends and suborbital space begins. This can lead to a fuel problem also.

To reach orbit that way, NASA needs some 520,000 gallons of rocket propellant and two strap-on rocket boosters to loft a 100-ton space shuttle and its cargo into space in just under nine minutes. Flying horizontal, would require much more conventional fuel than an aircraft—or a space shuttle—could carry.

However, there are ways for aircraft-based vehicles to reach space. Aerospace designer Burt Rutan and his firm Scaled Composites built a suborbital rocket ship—SpaceShipOne—which they dropped from a high-altitude aircraft. Once clear, SpaceShipOne pilots aimed their vehicle skyward, ignited its rocket engine and reached suborbital space before sailing back to Earth.

The U.S. military's X-15 rocket planes, too, reached the edge of space in a similar manner.

At least one firm, Oklahoma's Rocketplane Global, Inc. is hoping to refit a private jet airframe with rocket engines for tourism flights to suborbital space. (ANI)