Nah, you're still not getting it. This has to do with total impulse, not that the thrusters are "too small." I promise the cold gas thrusters are pretty dang powerful on the F9 booster.
Or, they could make the tanks the right mass and feed the thrusters long enough, but the thrusters would be underpowered. You can pick two of the three (mass, impulse, thrust), but that's it.
it is obvious that moving the cradle is easier then moving the rocket. in final moments any wind gust can ruin everything. and cradle is only need to hold 300 tons. for example some bridge cranes could move 750 ton things. after catching the booster it could be positioned/transported (if you have enough long rails you could catch it 300-400m off the pad) to launch hold downs.
Parts of the cradle will need to move simply to absorb the energy of impact. Just like a docking port or landing legs.
Quote from: Robotbeat on 01/26/2017 05:15 pmParts of the cradle will need to move simply to absorb the energy of impact. Just like a docking port or landing legs.Obviously. But dampening motion is not the same has having an actively moving landing cradle.
The booster will have the precision to find it's landing pad from space; the center of the landing pad from the start of the landing burn and the ability to adjust to the center and land gently from 2 meters up.
Quote from: Doesitfloat on 01/26/2017 08:17 pmThe booster will have the precision to find it's landing pad from space; the center of the landing pad from the start of the landing burn and the ability to adjust to the center and land gently from 2 meters up.not possible. It may find it, but hitting is a different matter. Show me an airplane on autoland hitting the exact same spot.
The only way to gently land is with some kind of springiness. On F9, that's the legs and the cylinders of the legs. You're not going to have two hard surfaces (one stiffly connected to the rocket and the other to the ground) collide without some kind of damage. Just like docking in space, you're going to need something to absorb that energy. Basic physics.
Hey - opinions vary.I don't think hitting the release mechanism (mm accuracy) is feasible, and even if it were, it's a waste of resources on the rocekt.I don't think an active catcher for such a large body makes sense either.So I have a passive or half-active "final guidance" rails that will bring the rocket in from ~1-2 m accuracy to final capture.This will remain open for debate till we see what SpaceX has in mind, and even then, it'll be open to debate as to how they should have done it.
What could you do to bring it close enough? Precision landing like BFR. You'd want, as Jim pointed out above, reproducible within feet/inches, which would be hard if not impossible.That you could do with the current design, forget about the mechanism for the moment. Because neither is the vehicle suitable structurally nor is the landing platform (it moves!). So what would be structurally and operationally suitable? Well, the vehicle accepts landing loads from where the legs attach, as well as being stablized with. So remove the legs from the LV and have a mechanism from the barge that performs the same functions when the LV has completed its precision approach.
Quote from: Space Ghost 1962 on 01/27/2017 12:14 amWhat could you do to bring it close enough? Precision landing like BFR. You'd want, as Jim pointed out above, reproducible within feet/inches, which would be hard if not impossible.That you could do with the current design, forget about the mechanism for the moment. Because neither is the vehicle suitable structurally nor is the landing platform (it moves!). So what would be structurally and operationally suitable? Well, the vehicle accepts landing loads from where the legs attach, as well as being stablized with. So remove the legs from the LV and have a mechanism from the barge that performs the same functions when the LV has completed its precision approach.Appreciate the gradual approach, and learning with F9 first. But do so on land; don't bother with the barge.