At the end of the last episode, I mentioned that the new Mark1 Cockpit was messing up many of my old designs because kerbals could no longer enter or exit the cockpit (because of the repositioned hatch). I'm not sure what I was doing wrong with trying to carry over the Mark1 Cockpit files from 0.90 to 1.0.5, but I was getting a plain white cockpit that wasn't working quite right. I received some suggestions to look on KerbalStuff for a mod that restores that old part.
3dmark 11 1.0.5 Keyl
Before sending out new ships to Duna, I first needed to test which ones no longer worked as designed in version 1.0.5 of KSP (and which of the replacement ships I built in 1.0.1, etc., still worked in 1.0.5). This involved a lot of "simulations" using the software that I use to simulate flight conditions in KSP...which is, of course, KSP itself. Let me just do an F5 before we have some alternate universe fun...then we can visit Nelemy, Hellou, and Kurt in their Duna Lander sitting on Duna's southern polar cap by the SSTV Pyramid.
One of the big changes I found during testing was that the landing profile I had previously used on Duna in 0.90 was not going to work in 1.0.5. That procedure was: Drop in from orbit...wait for any signs of entry flames to disappear (usually there weren't any flames from low orbit)...then deploy the parachutes at about 5 km and let them do almost all of the braking...then settle the slowly-descending ship under its many parachutes onto the surface with a little rocket braking burn.
The problem in 1.0.5 was that the parachutes now get destroyed if they are deployed at high velocities. Some of my Duna ships have a lot of drag and relatively low mass, and the thin Dunan atmosphere can actually slow down those ships to safe speeds in time to deploy the parachutes (assuming a lowland landing site). But many of my Duna ships have a high ballistic coefficient because they are carrying a large mass of fuel, and those ships were still screaming in through the thin air at over 600 m/s when it was time to deploy the chutes...and that just wasn't going to work in 1.0.5.
The other problem in 1.0.5 was the nerfing of the thrust and specific impulse ratings for many of the engines compared to 0.90 (especially the 48-7S engine). So I was concerned that some of my ships would no longer function as designed when used in 1.0.5. The Duna Landers, for example, come in with a full load of fuel (minus what gets used for the deorbit burn) because those lander/habitat/labs are supposed to be able to hop back to orbit, refuel, and land at different locations. So...were they still useful in 1.0.5?
Of course, Nelemy had an unfair advantage with this boost: That Lander had been landed back in 0.90 with parachutes doing almost all of the braking (even at the 3,000+ meter elevation of the SSTV Pyramid site). How much fuel would the old lander design have if it had landed in 1.0.5? This would require some testing.
I again targeted to a lowland site, I let the Lander come screaming in (we now get entry flames from a 90 km orbit in 1.0.5), letting the aerodynamic drag act as long as possible to slow the ship. But at 6,000 meters, the ship was still streaking along at almost 700 m/s, so I fired the two Thud engines at 100% throttle. As soon as the parachute icons in the staging display changed to the grey background color of "safe to deploy," I popped the chutes and cut the engines. The ship had slowed to safe-chute-deployment-speed at 1,600 meters (things were happening fast, so I wasn't as quick on the draw as I could have been in deploying the chutes and cutting the engines...see below).
So the old landers are still usable, if one is careful. But replacement Landers could be improved by the inclusion of two modifications: 1) The addition of drogue parachutes that can be deployed at higher speeds to help slow the Lander sooner, saving more fuel during landing; and, 2) slightly more efficient engines (the Aerospike is superior to the Thud on 1.0.5 Duna). New Landers with these modifications will be sent to Duna.
But, alas, in KSP 1.0.5, the nerfing of the 48-7S engine left the Duna Fido woefully underpowered. As shown below, it struggles to lift off from Duna. It is very slow to accelerate and push its very draggy frame through the Dunan atmosphere, and it falls far, far short of reaching orbit.
The Fuel Fidos that are still in orbit will have an easier time landing because of their draggy frames, and they can have their propellants removed to lighten them even more if needed. But replacements from Kerbin will have more thrust and drogue chutes to ensure that they will work for landing on 1.0.5 Duna.
In a simulation where the Tug landed offshore, it was interesting to see that the side tanks of the Tug were destroyed by the landing (I guess water is still tougher than land in 1.0.5), but the detached NERV engines settled safely to the sea floor to await recovery.
And you know what comes next? Of course you do! A BANT 3 is going to be overkill for a payload this light, and I'd previously have re-used one of my older smaller Tugs for this job, but those Tugs were not designed for the modern world of 1.0.5.
EDIT: Aerocapture at Duna is certainly doable in 1.0.5, provided you don't try to go from a fast, bad transfer into a very low Duna orbit all in 1 pass. Getting down below 12km or so is only necessary in such cases, and only that seems to melt engines. Otherwise, no problem that I've found.
OK...So the Lander/Habs are still OK...or as OK as they were after the change to 1.0.5...which is to say, they could still make it to orbit and land safely if done carefully...but new ones will be sent that have upgraded systems, as described in the previous episode (I'm assuming the aerodynamics have not changed a lot since those previous tests in 1.0.5). 2ff7e9595c
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