Orbital flight vs suborbital flight is a bigger step then you might think. For orbital flights the vehicle is traveling at least 28,000 km/h where as to reach 1

Orbital flight vs suborbital flight is a bigger step then you might think. For orbital flights the vehicle is traveling at least 28,000 km/h where as to reach 125 miles above Earth, a suborbital vehicle only needs 6,000 km/h. This can dramatically effect the survivability on reentry. Orbital and sub orbital flights are very different.