Crewed Launch to Duna
Mar. 31st, 2024 07:01 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
the_sky_callsImmediately following the discovery of the great statue on Minmus, Mission Control reported a similar signal coming from Duna and offered up a mission there. That launch window was at that time quite a long ways away and I spent that time completing tours of other discoverables on Kerbin, the Mun, and Minmus plus, when launch windows presented themselves, missions to Moho and Jool. Well, the primary mission launch window is here and it’s time for Kerbals to go interplanetary.
According to the KSP delta-V Map or the in-game Trip Planner:
Launch to Kerbin Orbit 3,400 m/s +20% = 4,080 m/s
Ejection and Transfer to Duna (930 + 130 m/s) + 20% = 1,272 m/s
Orbit and Circularize at Duna (250 + 360 m/s) +20% = 730 m/s
Land on Duna 1,450 m/s + 30% = 1,888 m/s
Launch to Duna Orbit 1,450 m/s +20% = 1,740 m/s
Return to Kerbin (360 + 250 + 360 m/s) + 20% = 888 m/s
We start building backwards with the return capsule. A Mk 1-3 “Gumball” capsule, all its associated things, an X200-8 Fuel Tank and a RE-L10 "Poodle" engine clocks in at 1,392 m/s of delta-V. That’s plenty to get back. That is also going to need to be the capsule that ascends from Duna’s surface. Not quite enough for both but if I use what’s left in the descent module for the ascent and then dock and refuel with the transfer stage in orbit before returning to Kerbin, it should be workable.
Adding a X200-16 Fuel Tank and another “Poodle” engine gives my descent stage 1,423 m/s. Again, that’s under the needed value but a bunch of the descent is going to be for free using four additional Mk-16 parachutes. I should have enough dV remaining to help with the ascent.
My concern is that I won’t have quite enough fuel to make a precise landing next to the target. If I don’t, I’ll miss out on the science gathered from the “Science Jr Jr” I’ll be gathering science shortly from my mission to Moho so I don’t think I’ll miss it too badly.
An X200-64 with a LV-T45 "Swivel" is the transfer stage and, because I am going to refuel, I slap on an extra X200-16 Fuel Tank just to be sure. That delivers 2,643 m/s of dV, which is plenty when I only need 2,002 m/s.
Now, to the launcher. Having opened the top node of Tech Level 2, I have the S4 KS-25 "Vector" engines. When I was playing KSP1, I rarely used the Vector but I have come to really like the engines. My ships to Jool were built on suggestions from the Optimal Rocket Calculator website consisting of basically a core of two X200-64 tanks and two Vector engines with two boosters on the side consisting of three X200-64 tanks and three "Vecto"r engines on each. This Duna rocket had a similar recommendation but I decided to split the two 3-tank/3-engines into three 2 tank/2 engine boosters. Basically. I needed to add a few tanks for aerodynamics and to round it all out.
In the end, the booster shows 4,799 m/s, which is a metric crap ton more than is necessary. If KSP2 had a budget to be concerned with, I would tweak it to save money but Kerbin is apparently a socialist economy or, at least, the space program is gifted with an infinite budget so if a rocket is overpowered and over budget, so be it. My only limit is the tyranny of the rocket equation.
Mission Designation : NER-1
Rocket Model : Neriene D-III
Total delta-V (to orbit) : 10,257 m/s (5,458 m/s)
Surface TWR : 1.62
Total Mass (to orbit) : 387.08 t (70.28 t)
Dry Mass : 81.76 t
Part Count : 112
Height : 38.30 m
Width : 6.70 m
Length : 7.23 t
Mission Objectives : :Land at discoverable on Duna
Crew : Bill Kerman, Erbert Kerman, Huduki Kerman
The thing with the disappearing trajectory lines happened again and I used the ALT-F8 to cheat myself back into the orbit I had already attained to allow me to build a maneuver node and keep from randomly falling out of the sky.
The transfer burn is about 1,143 m/s, which is 130 m/s less than predicted, but remember that the delta-V Map or the in-game Trip Planner is an average or estimate and the orbits are not circular or entirely without inclination (though Kerbin’s is). There will be some variations, part of why I add 20% to pretty much everything.
That, and I am controlling this with a keyboard, my reactions, and my eyeballs. Not precision instruments.
Once on my way, the midcourse correction in 150 days. Only 8 m/s. That will leave 1,500 m/s for capture and insertion. I will only need 730 m/s, and remember, that leftover fuel is going to be used for the trip back.
Arrival at Duna is 274 days. That’s a long time to be crammed into an Apollo-style capsule. Sitting in corners and reading a lot of e-books would be the order of most days when they aren’t tasked with exercising to keep bones and muscles from turning into goo.
There is an Eeloo launch window coming up but my best antenna is not good enough to maintain communications at this point. My mission to Moho will be arriving soon and, only 14 days after that, another Moho window will open up. Time to start building landers and rovers.
According to the KSP delta-V Map or the in-game Trip Planner:
Launch to Kerbin Orbit 3,400 m/s +20% = 4,080 m/s
Ejection and Transfer to Duna (930 + 130 m/s) + 20% = 1,272 m/s
Orbit and Circularize at Duna (250 + 360 m/s) +20% = 730 m/s
Land on Duna 1,450 m/s + 30% = 1,888 m/s
Launch to Duna Orbit 1,450 m/s +20% = 1,740 m/s
Return to Kerbin (360 + 250 + 360 m/s) + 20% = 888 m/s
We start building backwards with the return capsule. A Mk 1-3 “Gumball” capsule, all its associated things, an X200-8 Fuel Tank and a RE-L10 "Poodle" engine clocks in at 1,392 m/s of delta-V. That’s plenty to get back. That is also going to need to be the capsule that ascends from Duna’s surface. Not quite enough for both but if I use what’s left in the descent module for the ascent and then dock and refuel with the transfer stage in orbit before returning to Kerbin, it should be workable.
Adding a X200-16 Fuel Tank and another “Poodle” engine gives my descent stage 1,423 m/s. Again, that’s under the needed value but a bunch of the descent is going to be for free using four additional Mk-16 parachutes. I should have enough dV remaining to help with the ascent.
My concern is that I won’t have quite enough fuel to make a precise landing next to the target. If I don’t, I’ll miss out on the science gathered from the “Science Jr Jr” I’ll be gathering science shortly from my mission to Moho so I don’t think I’ll miss it too badly.
An X200-64 with a LV-T45 "Swivel" is the transfer stage and, because I am going to refuel, I slap on an extra X200-16 Fuel Tank just to be sure. That delivers 2,643 m/s of dV, which is plenty when I only need 2,002 m/s.
Now, to the launcher. Having opened the top node of Tech Level 2, I have the S4 KS-25 "Vector" engines. When I was playing KSP1, I rarely used the Vector but I have come to really like the engines. My ships to Jool were built on suggestions from the Optimal Rocket Calculator website consisting of basically a core of two X200-64 tanks and two Vector engines with two boosters on the side consisting of three X200-64 tanks and three "Vecto"r engines on each. This Duna rocket had a similar recommendation but I decided to split the two 3-tank/3-engines into three 2 tank/2 engine boosters. Basically. I needed to add a few tanks for aerodynamics and to round it all out.
In the end, the booster shows 4,799 m/s, which is a metric crap ton more than is necessary. If KSP2 had a budget to be concerned with, I would tweak it to save money but Kerbin is apparently a socialist economy or, at least, the space program is gifted with an infinite budget so if a rocket is overpowered and over budget, so be it. My only limit is the tyranny of the rocket equation.
Mission Designation : NER-1
Rocket Model : Neriene D-III
Total delta-V (to orbit) : 10,257 m/s (5,458 m/s)
Surface TWR : 1.62
Total Mass (to orbit) : 387.08 t (70.28 t)
Dry Mass : 81.76 t
Part Count : 112
Height : 38.30 m
Width : 6.70 m
Length : 7.23 t
Mission Objectives : :Land at discoverable on Duna
Crew : Bill Kerman, Erbert Kerman, Huduki Kerman
The thing with the disappearing trajectory lines happened again and I used the ALT-F8 to cheat myself back into the orbit I had already attained to allow me to build a maneuver node and keep from randomly falling out of the sky.
The transfer burn is about 1,143 m/s, which is 130 m/s less than predicted, but remember that the delta-V Map or the in-game Trip Planner is an average or estimate and the orbits are not circular or entirely without inclination (though Kerbin’s is). There will be some variations, part of why I add 20% to pretty much everything.
That, and I am controlling this with a keyboard, my reactions, and my eyeballs. Not precision instruments.
Once on my way, the midcourse correction in 150 days. Only 8 m/s. That will leave 1,500 m/s for capture and insertion. I will only need 730 m/s, and remember, that leftover fuel is going to be used for the trip back.
Arrival at Duna is 274 days. That’s a long time to be crammed into an Apollo-style capsule. Sitting in corners and reading a lot of e-books would be the order of most days when they aren’t tasked with exercising to keep bones and muscles from turning into goo.
There is an Eeloo launch window coming up but my best antenna is not good enough to maintain communications at this point. My mission to Moho will be arriving soon and, only 14 days after that, another Moho window will open up. Time to start building landers and rovers.
