Page:NASA Launch Vehicle Handbook.pdf/10

 and heat fairings on third and fourth stages are ejected. Thus far the ascent, as previously described, is identical for both probe and orbital missions however, after third-stage burnout, either of two procedures are followed, depending on whether the payload is an orbiter, or a probe. For probe trajectories, the fourth stage is spun up, ignited, and blast separated from the third stage 5 seconds after third-stage burnout. If there is a fifth stage, it is ignited immediately after fourth-stage nominal burnout time. For orbiters, the entire third stage with its hydrogen peroxide control system still operating coasts to the apogee of the ascent orbit, aligning itself to a programmed altitude for fourth-stage ignition. At this time the final stage is spun up, the fourth-stage ignites, and the third-stage motor is blast separated. If there is a fifth stage, it is ignited immediately after fourth-stage burnout. A typical four-stage nominal ascent trajectory is presented in the table below.

SCOUT ORBITAL-ASCENT TRAJECTORY

PAYLOAD = 100 POUNDS

--_t _V

sec

i BO. 41.3 4,589

_I, -'-n

_.x. N.X.

9.o2 6.4_

2l.J,(, l_.gi_

48.9"

35.3

•i

re_,_tlve)

2 I(N. 7_.3

2 BO. ll_.O 3,9._:' .lo, 371

_ IGN. 120.0 10,312

_ BO. 159.4 17,648

4 IGN. 47_.2 15,974

4l.lO56.4O

_._o 6_0.

7_.10 Z_6.40

_O._O 886.7_

_5.z

25.5

2o._

I.0

A-3

_BO. __o0.2

27,036 _3o..'_ lC06.0_ 0