/sci/ - Science & Math

>>15681604
>>15681608
semi-long explanation from the video
during initial a phase called "rough braking phase" the thruster are at full force, after this there is a "camera coast" phase with low thrust before a "Fine breaking phase"
the problem was that the thrust was too high during the camera coast phase due to the valves controlling the thrusters not closing enough which results in there being too much thrust that causes the lander to actually ascend again instead of descend like it should have
the black trajectory on the picture is the planned one, the dashed blue line is the one that actually happened
it was hundreds of meters off the planned trajectory after the camera phase ending
the next part is hullos speculation, but to fix this the craft starts to point at the target (which it has now missed by hundreds of meters) and actually pitches so its almost upside down trying to rotate , but the rotation is so slow that after course correction and a rotation back to upright again its moving too fast and too close to the surface to decelerate in time
however this speculation is supported by doppler plots

tl:dw the software was built with the assumption that every step would go perfectly and when the constraints were broken by throoosting too much due to a faulty valve, it started doing retarded shit