Falcon Heavy to Duna

[vyznev]

11 hours ago, vyznev said:

Well, almost done. I still need to land the Tesla on Duna, but that's the easy part.

Okay, I *thought* that was the easy part. Wasn't actually quite so easy peasy after all, and the F9 button did see some use. Apparently I'd been lucky with my landing sites in my test runs, and consequently a bit too optimistic with the amount of delta-v needed. Anyway, I did eventually nail it -- landed on empty tanks and lost an engine, but I call that good enough. It's not as if those engines were going to be of any use with no fuel left, anyway, and they were only added to the Tesla for the specific purpose of getting it safely down on Duna. (Any reports of Jeb and Val using them for extra air time during the test drive are strictly denied by SpaceX. That would be really unsafe, anyway. No, I mean really unsafe. )

Spoiler

 

Anyway, here's the point breakdown:

• Gone For a Spin (10 points): Before the launch, demonstrate your Roadster's moves by driving it around the KSC. Check.
• Speed Demon (15 points): Test your Roadster at speeds over 100 mph (45 m/s). Check, see previous.
• Falcon Nine (27 points): Use nine engines on each of your booster cores. Check. (9 x LV-T30 on each booster, one LV-T30 on the upper stage)
• Autonomic (13 points): Use drone cores; nothing manned. Check. (A total of 7 probe cores used, including two on the Tesla.)
• Looking Easy (16 points): Recover at least one parallel booster. Check.
• Insane Mode (42 points): Recover both parallel boosters with boostback, RTLS (anywhere on KSC continent), and propulsive landing. Check. (Although technically I didn't really do a proper boostback, since I just aimed my initial launch trajectory to land the boosters back at KSC. I did end up doing a slight boostforward for one of the boosters, to make it land at the KSC peninsula instead of somewhere up in the hills to the west.)
• Downrange (19 points): Recover your center core. Check.
• Supercruise (18 points): Recover your center core by landing on a boat. Check.
• Tru Lyfe (33 points): All booster recoveries without chutes. Check. (Not a single parachute was used on the entire vessel. Plenty of airbrakes, though.)
• Hail Mary (28 points): Bring back the upper stage. Check. (I assume anywhere on Kerbin counts, because I ended up landing it almost on the opposite side of the planet from KSC.)
• Double Trouble (26 points): Build your own fairings and recover at least one. Check, sorta. (Upper stage had a shuttle-style cargo bay, which was recovered. Apparently that counts. In any case, no disposable fairings were used; the only stock fairings on the craft were used as custom nose cones and/or interstage shrouds on the boosters, and were recovered intact.)
• Purity (30 points): No mods. Check, hopefully. (The only mods used during the actual flight were purely for cosmetic and informational purposes. See list of mods below.)
• Destination (22 points): Land your Roadster on Duna and take it for a spin! Check. 

I also went for the "pretty difficult" bonus challenge of landing every booster in a single save, rather than just landing one and then using F9 to go back and land the next one. (F9 was still used aplenty, but only to retry failed landing attempts. ) I actually came up with a clever trick for that:

Spoiler

If you look at my booster design, you can see that there are small X200-16 fuel tanks at the top and the bottom. The bottom tanks are reserved for landing, and are disabled at launch. The top tanks on the side boosters, however, have their fuel priorities lowered asymmetrically: one of them is set to -1 relative priority, and the other one to -11, causing it to drain after the center booster tanks. This means that, if I just kept firing the engines without staging, the tanks would drain in this order: side booster big tanks -> left booster top tank -> center booster big tanks -> right booster top tank.

But what I actually do, after lauching nearly vertically (tilting very slightly east to try and keep the predicted landing site for the side boosters near KSC), is decouple the side boosters while the center tanks are still about half full (about when apoapsis hits 90 km or so, IIRC), with the engines firing. At that point, the left booster has no more accessible fuel (since the bottom tank is disabled) and so shuts down, while the right side booster still has a full top tank that will boost its apoapsis to about 250 km or so. And all this happens automatically, while I manually turn the center booster to about 45° pitch, heading 90°, to boost its apoapsis even higher and start the circularization. This way, as long as I just time the side booster separation right, I'll have all the booster landings nicely staggered. There's also a time interval where all the boosters are in space, letting me freely switch between them to fine-tune the landing sites and do other necessary preparation (enable bottom fuel tank, deploy airbrakes, etc.). Also, with proper steering at launch, the side boosters will land more or less straight down at KSC without the need for any significant boostback burns.

Mods used:

• DCK, for repainting the Tesla and the fuel tanks. No DCK custom parts were used.
• KER, purely informational (but absolutely essential; there's no way I could've possibly flown this mission without it).
• KAC, for launch window planning and to make sure I don't forget my maneuver nodes.
• MechJeb, used only for the landing site map crosshair (purely informational) and for deploying the droneships (for atmospheric heading and altitude hold, which the stock SAS lacks).

I hope all of these are acceptable for the Purity subchallenge. The only one I think might be questionable is MechJeb, but I didn't actually use it to fly the spacecraft at any point.

Anyway, expect a more detailed writeup, craft files and video of the whole thing at some indefinite time in the future. 

 

[Avo4Dayz]

Anyone try to build recoverable fairings yet? I have....

I flew one on top of my stock falcon 9 design, running 9 Rellant engines

Initially built in VAB, turns out created heaps of lift causing instability issues of rocket.... So then I put my fairing in a fairing so I could test just the fairing coming home.

https://imgur.com/gallery/1e6sl

I went on to design Fairing 2.0 which flew waay better, but I am not sure if I feel the points awarded for just this bit are worth it.

[LightBender]

On December 25, 2017 at 12:56 PM, sevenperforce said:

With the Falcon Heavy's first test fire just days away, Elon's personal Tesla already mounted to the PAF, and the launch to Mars expected next month, what better time than Christmas break to build a Falcon Heavy in KSP and use it to send a battery-powered sports car to Duna?

The Challenge: Build a battery-powered two-seat rover (with a probe core, please; this IS a Tesla we're talking about), mount it on the single-engine upper stage of a three-stick parallel-staged launch vehicle, and send it to a Duna-intersecting orbit! Recover as many components of your launch vehicle as possible.

All mods are allowed, but try to keep it as close to stock as you can, and name whatever mods you use.

Scoring is based on accumulation of points as follows:

• Gone For a Spin (10 points): Before the launch, demonstrate your Roadster's moves by driving it around the KSC.
• Speed Demon (15 points): Test your Roadster at speeds over 100 mph (45 m/s).
• Falcon Nine (27 points): Use nine engines on each of your booster cores.
• Autonomic (13 points): Use drone cores; nothing manned.
• Looking Easy (16 points): Recover at least one parallel booster.
• Insane Mode (42 points): Recover both parallel boosters with boostback, RTLS (anywhere on KSC continent), and propulsive landing.
• Downrange (19 points): Recover your center core.
• Supercruise (18 points): Recover your center core by landing on a boat.
• Tru Lyfe (33 points): All booster recoveries without chutes.
• Hail Mary (28 points): Bring back the upper stage.
• Double Trouble (26 points): Build your own fairings and recover at least one.
• Purity (30 points): No mods.
• Destination (22 points): Land your Roadster on Duna and take it for a spin!

Leaderboard:

1. @Ultimate Steve: 277 points
2. @LightBender: 196 points
3. @sevenperforce: 190 points

Q. Did this challenge die enough to where I'm still holding second?