MR. P
Do you believe or is it possible to reach NEO with balloons or SGV's (specific gravity vehicles)?
Dave Darling said:Definitions vary. According to some, LEO includes orbits having apogees (high points) and perigees (low points) between about 100 km and 1,500 km. Others extend that range up to 2,000 or 3,000 km. In some cases, the distinction between LEO and MEO (medium Earth orbit) is dropped and LEO is considered to be any orbit below geosynchronous altitude. The majority of all satellites, as well as the Space Shuttle and International Space Station, operate from LEO.
from http://www.hobbyspace.com/NearSpace/ .The realm of Near Space officially lies between 75,000 feet (~23km) and and 62.5 miles (100km) according to the International Aeronautical Federation (FAI). Here we consider a wider range that extends up to 200km or so where it becomes safe for satellites to remain in orbit without immediately becoming dragged down by friction with the residual atmosphere.
The vehicles that traverse this high altitude domain are called nearcraft. These include sub-orbital rockets, which make quick jumps into and out of near space, and high-altitude balloons that can loiter there for extended periods.
Weather balloons routinely go to 27km (~90k ft). Scientific balloons go to 42 km (137k ft or 26mi) and remain at high altitudes for several days. The world record altitude reached by an unmanned balloon is 51.82km (170k ft or 32.2mi).
The record for altitude reached by a crewed balloon was set by Malcom D. Ross and Victor A. Prather who flew to 34.668km (113,740ft or 21.54mi) on April 5, 1961.