[Steely Tom]

It is similar to making a good, no-hover landing in a helicopter. You have to zero forward velocity, vertical rate of descent and altitude to coincide with a fixed point on the ground. When you manage to do it smoothly, it is quite satisfying.

Also, in the SpaceX case, they had to bring yaw and pitch angles and yaw and pitch angular velocities to zero at the same time that they got velocity and vertical rate of decent to zero, with fuel running out at the rate of pounds per second.

[BwanaNdege]

They will eventually make this landing. When they do, it will deserve the Collier Trophy for the most outstanding achievement in Aviation for the year.

You are exactly correct when you said “they had to bring yaw and pitch angles and yaw and pitch angular velocities to zero at the same time that they got velocity and vertical rate of decent to zero, “

I believe this was what threw them off on this landing. Perhaps the barge position reference data is not sufficiently gyro stabilized and the slight rocking is confusing the sensors on the booster. They have managed to “stick” the landings on dry ground, though that was from an initial altitude of 2500’ or so.