You also have to remember that it will produce 7G on approach which is far too high for a deconditioned crew to handle.
2) Red Dragon, as currently proposed, is not really breaking new ground in the way that people are claiming. The propulsion is not to kick in until < mach 3. This is within the range of heritage parachute systems, which would be a more mass-efficient solution.
Sorry but no. No way you can land safely seven tonnes on Mars with today's parachute technology. Too fast too low.Even MSL, a much, much lighter payload (so smaller ballistic coef., so higher at the same speed), needs rockets for final approach.Red Dragon, if ever successful, would be braking new ground because landed mass would be more than five times that of any previous lander, and because it would not resort to parachutes at all.
Only Beagle 2 tried to do without it and look what happened to that.
Unless you know something I don't, there is no correlation between it doing a landing without retros and its failure. That's like me saying propulsive landings are bad because MPL failed.
Here comes some more speculation on how SpaceX might do an early Red Dragon with minimal changes from DragonRider:1] Take a DragonRider, make the necessary propulsion/tankage changes for Mars EDL.2] Remove the docking system. In its place, add a 'cup' shaped pressure wall that descends into the stock pressure vessel, freeing up a large unpressurized volume. Keep the nose-cap fairing on through EDL to increase the available volume. Place your payload (e.g. science package) in this space.3] Once on Mars, deploy the nose cap, and push the unpressurized payload - including solar arrays and high-gain antenna, up out of the top of the spacecraft. The payload(s) would be entirely self-contained, all SpaceX would do is land it and push it out into the Mars environment to fend for itself. They could be provided by NASA, ESA, anyone.For surface access you need a similar but more aggressive mod:1] Remove the side hatch.2] Behind the hatch add a wall that opens up volume into the pressure vessel large enough to accommodate a small rover, robot arm, etc.3] Once on Mars, deploy the TPS cover over this area. It hinges down toward the surface with the fulcrum located low down where the grapple fixture is on DragonRider.4] If the you've brought a rover, mount it to the inner surface of this cover. Once the cover has hinged down to the surface, you release the mounts, and roll off. + I worry the new pressure walls could be heavy, but perhaps the Dragon atmosphere could be chosen (lowered) to minimize the strength needed?
On solar arrays: yes, I was envisioning phoenix-style solar arrays. Remember, I was suggesting the contents of the cup/tube are pushed upwards out of the spacecraft once its landed, so you have much more than just the top hatch-area to work with. If the cup were 2m deep, then the payload (occupying the cylindrical volume with a diameter about equal to a CBM) ends up rising 2m above the hatch level, i.e. high enough for solar arrays to fold down and deploy. This 'cylinder' has a huge area available for instruments, antennas, etc.The side-hatch idea could be used to place instruments on the surface rather than a rover. This could include a spectrometer, or a drill but I'm not sure this config is better than drilling through the heat-shield.And please remember, this is all just speculation.
A somewhat wacky idea for a Red Dragon precursor mission. Could a Dragon with trunk land on Phobos and take off again? Basically add some deployable legs inside the trunk and additional hypergolic tankage in the Dragon. Maybe just 2 or 4 Super-Dracos is all that's require for high impulse propulsion. Sort of a Fobos-Grunt like sample return mission.
Yeah, I kind of guessed that. I've criticised various schemes to modify Dragon to do other missions before so I thought I'd be a bit more laid back in my reply this time.No one's proposed a Dragon Venus lander yet. There's still time....
Wouldn't have all these low atmosphere complaints ;P. How about a buoyant OrangeDragon that floats around in high Venus atmosphere?
Quote from: Zed_Noir on 07/22/2012 07:09 amA somewhat wacky idea for a Red Dragon precursor mission. Could a Dragon with trunk land on Phobos and take off again? Basically add some deployable legs inside the trunk and additional hypergolic tankage in the Dragon. Maybe just 2 or 4 Super-Dracos is all that's require for high impulse propulsion. Sort of a Fobos-Grunt like sample return mission. It needs quite a high delta V budget to accomplish the round trip (too lazy to look up the numbers) so I'm not sure you could carry enough propellant inside the standard Dragon shape. Then there's the waste of transporting the heavy Dragon heat shield to Phobos and back just to return a small sample.If you're using all chemical propulsion it's much more mass efficient to split the craft into a lander and return vehicle with a small recovery capsule. That was the approach Phobos Grunt used.
Dragon needs the atmosphere to slow down enough to be able to land on Mars with its quite small delta-v (~600 m/s).Not enough to make orbit insertion
Reboot the proposal to a one way direct descend to Phobos, so no heat shield.
Cleaned up version of Red Dragon sample return concept from last months Mars concepts conference. The original was a cruddy video frame grab. They talked of pop-off panels to deploy the rovers, and upwards of 1,900 kg of fuel in expanded tanks.
