Return trajectory, as an important part of satellite recovery mission, is flight trajectory of spacecraft from its working orbit to required reentry point.
Spacecraft begins to decelerate under the backward thrust of engine and flies to the reference reentry point accurately under the control of attack angle and slide angle.
The optimal return trajectory can be described as follows: at the beginning of the second phase, the attack angle is almost 180[degrees], which means that the thrust has been turned to the same direction as that of the velocity; then the engine works to decline the velocity of spacecraft until the end of second phase; in the third phase, the spacecraft flies without power in a transition track; the attack angle and slide angle are adjusted to optimal values; and, in fourth phase, the engine works to accelerate reaching the reentry point.
3) The state errors between terminal state of optimal trajectory and reference reentry point state are listed in Table 3, which satisfy required precision.
Despite the Greek debacle, I doubt Goldman Sachs will fall below 180, an ideal reentry point
for those UAE investors who missed the bank's 30 per cent bull run since mid 2014.