Payload Launch Segment


 

 In a orbital payload launching mission:

  • Platform ascends to a predetermined altitude in stratosphere, where the air density is lower than the sea level and the wind is relatively slow and steady, and subsequently launches SLSS in a predetermined position and time window.
  • SLSS rockets to a predetermined velocity and altitude (above the atmosphere), opens its cargo bay doors and releases its cargo (i.e., an assembly of a conventional upper stage and payload).
  • The upper stage ignites and propels the payload to a predetermined space orbit.

Flight and Recovery


 

Stratospheric launch platform
  • At lift-off, hydrogen ballonet is partially folded to minimize platform's cross-section area. As the platform ascends, lifting gas expands and the platform turns out more like a streamlined body. In ascent stage, engines are initially shut down until the launch platform ascends to a predefined altitude.
  • Soon after the SLSS is launched, hydrogen lifting gas is completely vented. The hydrogen ballonet subsequently is folded on helium ballonet surface.
  • The helium ballonet is gradually inflated as the platform descends, to keep the helium ballonet in a streamline shape and assist adjusting the altitude in platform's return stage.

 

Stratospheric-launched suborbital shuttle
  • SLSS  is launched from stratospheric launch platform, burns cryogenic fuel, propels its cargo (an assembly of upper stage and payload) to an altitude above the atmosphere and a suborbital speed
  • After its launch, SLSS follows one of two different flight profiles:
    • Regional: SLSS reaches a relatively lower speed at burnout. Its reentry takes a large lateral maneuver to shorten the distance from space port to its landing airfield; a tug aircraft will be employed to pull SLSS gliding back to the space port.
    • Round the Earth: SLSS reaches a speed close to the burnout speed of ICBM. After releases its cargo, SLSS takes a glide reentry flying around the earth and directly returns to the space port. 

Launch cycle


 

In ideal cases, time interval between platform's lift-off in current mission and that of the following mission, if employing the same launching system, can be as short as 8 hours. As shown in this diagram, this time budget includes payload launch, recovery of launch system, cargo loading, refuel and refill lifting gas. Briefly, the ideal launch cycle is 8 hours.