So why not just make a new heatshield, about 5m diameter to fit inside the Falcon PLF, and make a proper Mars lander of around two or three tonnes. No new technology required.
Wonder if the Dragon capsule can do additional atmospheric braking maneuvers like the shuttle.Have the Dragon on a lot of banking turns to shredded delta V with RCS.Since the heat shield is rated for Mars return to Earth supposedly. Can the Dragon fly through the Martian while doing banking turns until it's speed dropped below supersonic? Maybe even going around Mars several times along the equator.
Quote from: Kaputnik on 09/09/2011 08:24 amSpaceX are good at doing the things other people did already, but cheaper. Aerocapture is not playing to their strengths.
Quote from: Kaputnik on 09/09/2011 08:24 amSo why not just make a new heatshield, about 5m diameter to fit inside the Falcon PLF, and make a proper Mars lander of around two or three tonnes. No new technology required.The premise of this thread is that dragon could be used to deliver a science payload to the surface of Mars. Not to design a new 2 or 3 tonne lander, but to figure out how Elon might be planning to make dragon do the task.
"This would possibly be several tons of payload — actually, a single Dragon mission could land with more payload than has been delivered to Mars cumulatively in history," -Elon
Would it work to have a large (12+ meter diamter) trunk-stowed ballute pop out for the primary deceleration? Once subsonic, deploy the dragon parachutes to get up off the trunk/ballute, then super-dracos for the final touchdown? Can the solar panels be retracted back to the trunk once extended?Perhaps the trunk might even be recoverable more or less intact (the ballute could act as an airbag potentially). Then the solar panels could re-deploy and the trunk could be used as a solar-powered (unpressurized) storage shed.
Wonder if the Dragon capsule can do additional atmospheric braking maneuvers like the shuttle.Have the Dragon on a lot of banking turns to shredded delta V with RCS.
Can they approach in an elliptical orbit and decelerate in a series of orbital passes? Is this too time consuming or dangerous? Could the process be improved by firing Draco's at the low point of each orbit?
Quote from: DaveH62 on 09/10/2011 02:57 amCan they approach in an elliptical orbit and decelerate in a series of orbital passes? Is this too time consuming or dangerous? Could the process be improved by firing Draco's at the low point of each orbit? They probably could take a number of passes through the atmosphere- this is aerobraking, and is used on most Mars missions, so is well understood. No need to waste propellant firing the Dracos at periapsis.But all it lets you do is get down to a low circular orbit so that you enter at minimum velocity- and that is already presumed when working out how Dragon will fare in Mars entry.
QuoteWould it work to have a large (12+ meter diamter) trunk-stowed ballute pop out for the primary deceleration? Once subsonic, deploy the dragon parachutes to get up off the trunk/ballute, then super-dracos for the final touchdown? A large ballute could well be the answer but who is going to develop it? Maybe if you fast-forward ten years Musk might be working on this sort of thing in the context of US recovery, but at the moment what they know is PICA-X rigid heatshields.
Would it work to have a large (12+ meter diamter) trunk-stowed ballute pop out for the primary deceleration? Once subsonic, deploy the dragon parachutes to get up off the trunk/ballute, then super-dracos for the final touchdown?
But are they not simply firing the thrusters to rotate the dragon, which will have an off-centre CG and will therefore generate lift in a certain direction. This is how Apollo worked.
Quote from: Kaputnik on 09/13/2011 01:22 pmBut are they not simply firing the thrusters to rotate the dragon, which will have an off-centre CG and will therefore generate lift in a certain direction. This is how Apollo worked.But this still is firing a rocket engine into hypersonic airflow. Doesn´t it have any impact on capsule stability?
Quote from: yamato on 09/13/2011 02:24 pmQuote from: Kaputnik on 09/13/2011 01:22 pmBut are they not simply firing the thrusters to rotate the dragon, which will have an off-centre CG and will therefore generate lift in a certain direction. This is how Apollo worked.But this still is firing a rocket engine into hypersonic airflow. Doesn´t it have any impact on capsule stability?Not into the flow, but firing at a tangent to the circumference of the capsule. The MSL landing video has a good illustration of this. Since it is only rotating the capsule around the vertical axis, only a small force is required, so there is no effect on stability.
Quote from: Kaputnik on 09/09/2011 08:24 amSpaceX are good at doing the things other people did already, but cheaper. Aerocapture is not playing to their strengths.Propellant cross feed.
SpaceX are good at doing the things other people did already, but cheaper. Aerocapture is not playing to their strengths.