Space travel has made significant gains in recenyt years as a niche in aviation, with governments, space agencies, and private companies competing to explore space for scientific and recreational purposes. This requires venturing into space through different means depending on the purpose. Two spaceflight methods exist - orbital and sub-orbital. The primary difference between the two is speed and altitude.
The vehicle’s speed is the primary difference between orbital and suborbital space flights. The primary variable when determining speed is the orbital velocity, which refers to the speed it must attain to remain in orbit around the planet at a given distance above the earth. The vehicle remains in orbit for extended periods and is well adapted to astronauts conducting experiments in space for days or months. Orbit velocity at 125 miles requires a spacecraft speed of 17,500 miles per hour or Mach 23, which is 23 times the speed of sound. This requires complex engineering, materials, and skills, making orbital space flights expensive.
On the other hand, sub-orbital flights do not require the vehicle to attain orbital velocity. Thus, the vehicle can travel at lower speeds. Ascending 125 miles, a sub-orbital vehicle needs to reach 2,200 to 3,600 miles per hour. Rather than the constant speed associated with orbital flights, the sub-orbital flight only needs to ascend to an altitude above 62 miles above sea level, which defines the minimum height to qualify as a sub-orbital flight (still entering space), then start descending once the engines switch off.
Sub-orbital flights, however, rarely reach an altitude of 125 miles. They average between 50 and 70 miles above the earth. The descent toward earth causes a free fall and a few minutes of weightlessness for the occupants. The experience makes the sub-orbital flight ideal for space visitors simply seeking the thrill of a brief experience of space.
