local krpc = require 'krpc'
local platform = require 'krpc.platform'
local conn = krpc.connect('Sub-orbital flight')

local vessel = conn.space_center.active_vessel

vessel.auto_pilot:target_pitch_and_heading(90, 90)
vessel.auto_pilot:engage()
vessel.control.throttle = 1
platform.sleep(1)

print('Launch!')
vessel.control:activate_next_stage()

while vessel.resources:amount('SolidFuel') > 0.1 do
    platform.sleep(1)
end
print('Booster separation')
vessel.control:activate_next_stage()

while vessel:flight().mean_altitude < 10000 do
    platform.sleep(1)
end

print('Gravity turn')
vessel.auto_pilot:target_pitch_and_heading(60, 90)

while vessel.orbit.apoapsis_altitude < 100000 do
    platform.sleep(1)
end
print('Launch stage separation')
vessel.control.throttle = 0
platform.sleep(1)
vessel.control:activate_next_stage()
vessel.auto_pilot:disengage()

while vessel:flight().surface_altitude > 1000 do
    platform.sleep(1)
end
vessel.control:activate_next_stage()

while vessel:flight(vessel.orbit.body.reference_frame).vertical_speed < -0.1 do
    print(string.format('Altitude = %.1f meters',
                        vessel:flight().surface_altitude))
    platform.sleep(1)
end
print('Landed!')