<i>>> The climber isn't going to generate enough acceleration<br /> /> For the MSL landing it needs to accelerate upwards 1 Martian G, 3.8 m/s for 6 seconds starting at an elevation of 85 m. The energy supply to accelerate upwards is only needed for 10 seconds, 6 seconds to land with 4 seconds moving upwards at a constant velocity for insurance.</i><br /><br />I think Jim is inferring that the winch's torque will "yank" the parachutes downward without actually decelerating the payload that much. Mars' atmosphere is 1% the density of Earth's, it is a much different fluid to move through. 85m to 0m is not much margin for error. <br /><br />On the smaller proposed payloads, the winch is the weak point, IMHO, in terms of mass and failure points. On larger payloads, the weak point is the cabling, because there is going to be a lot of it that must work. This even assumes that it can be done.<br /><br />For lighter payloads, current techniques seem to work fine. The real question is landing items heavier than the Mars Surface Lab. How to deliver 5t to the surface, or more? Is powered decent the only way to go for crew?<br /><br />A different landing method that I've been pondering would include a ram-air airbag in a fairly standard heat shield, similar to that used on Mercury. The payload is behind this with an aeroshell around it. A small cruise stage is above. During EDL, a small drogue chute trails, eventually deploying several large chutes. Several km above the surface the aeroshell detaches and reveals several down-angled SRBs. This provides more drag (per Pathfinder) and at terminal decent the SRBs trigger until touchdown. At line-slack, the aeroshell/chute combo detaches and rockets away. The drop-down airbag cushions the landing. Off-topic but more scalable. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>