Suborbital research hitches a ride on commercial space cruisers, Physics Today

"The promise of frequent, relatively inexpensive flights to suborbital space has attracted a growing number of researchers who are poised to send, or even accompany, experiments on multi-use commercial spaceships. The fledgling commercial space sector is now testing manned and unmanned rockets that could cruise for three or more minutes in a steady-state, low-vibration microgravity environment at altitudes around 100 km. Commercial space vehicles can take an experiment to space and bring it back at far less cost than conventional unmanned, single-use NASA rockets or a trip to the International Space Station, if one can even be arranged."