Weekly Challenge #8 - Build Starship!

Ghostii_Space · April 14, 2023

Hello Kerbonauts!

This week we were inspired by SpaceX's Starship!

Primary: Build a Starship replica and fly it to orbit

Stretch: Build a Starship replica and land it on the Mun

Jeb Level: Fly a Starship replica to orbit and land it propulsively at one of KSC's four landing pads

Val Level: Refuel a Starship replica at a fuel depot in Low Kerbin Orbit, land it on Duna, and then return to KSC

Little 908 · April 14, 2023

I hope this doesn’t turn out like a big explosion on the launchpad…

edit: wow I didn’t realize how many cargo bays there were until now!

Edited April 16, 2023 by Little 908
edit

PyroSA · April 14, 2023

The accuracy of my re-entry and landings immediately rule out Jeb Level.

TheBlackJackal · April 15, 2023

20 hours ago, PyroSA said:

The accuracy of my re-entry and landings immediately rule out Jeb Level.

Practice makes perfect!

18Watt · April 16, 2023

Val Level Complete! I didn't hit the center of the pad, but at least found a landing pad.

Launch and Duna landing:

Spoiler

The Starship in the VAB. Lower stage has 9 Vectors. Upper stage has 4 Vectors. I think 3 Vectors in the upper stage would have been plenty, but it's not easy to test stuff without being able to F12 ships into position. So I went with a little overkill, just in case.

Launch. The upper stage reaches LKO with about 2,400 dv remaining. (This screenshot is missing two Kerbals, and even though you can't see it, the upper stage is missing the docking port for some reason.)

Sent a tanker up to refuel the Starship. Now it has a tad over 5,000 dv. Should be enough to land on Duna and get back to Kerbin.

Odd graphics glitch arriving at Duna. Ike is behind Duna, but you can still see Ike through Duna. Also not sure why Duna appears light blue/green in this screenshot.

To save fuel for the return I'm using parachutes to aid the landing at Duna.

Landed. I didn't attach ladders for the Kerbals, so nobody is going to the surface. Can't remember if the jetpacks will work on Duna or not, but didn't want to chance it.

Headed back up to Duna orbit.

Return and Landing:

Spoiler

I had enough gas to circularize at Kerbin, but that didn't leave me much to land with. So I sent up another tanker to give Starship some more gas.

Approach to KSC. The thing is fairly controllable. I would not call it maneuverable, but it can change course significantly if you do it carefully.

At the end I pull up to vertical. I need assistance from the Vector engines to pull up, otherwise there isn't enough control authority to do that with any precision. Then deploy the landing legs, and start a controlled descent. Hope I have enough fuel! I can maneuver while descending, but had trouble determining if I was on track to hit the landing pad or not. I'll be happy if I even get close to the pad.

Almost there! Just a dozen meters or so off the ground, time to slow our decent to under 2 m/s. It's obviously not going to be a bullseye, but not sure if I have enough fuel to monkey around with my landing location.

Well, I hit the landing pad. SpaceX makes it look so easy. I felt pretty good about even getting that close, it's not easy.

Another shot of the rocket on the pad. Tall skinny landers like this tend to wobble a lot after touchdown. Not tipping over required having essentially zero lateral velocity on touchdown.

Oh, should mention I ran into an odd bug departing Duna. The game thought my departure burn should be Duna prograde to get to Kerbin. I know that's not correct, so I basically had to just eyeball the departure burn from Duna, as the maneuver nodes were giving me really bizarre information. So wasn't able to plan an efficient transfer from low Duna orbit directly to Kerbin. Still made it work, and probably only wasted about 400 dv.

Although the ship can obviously land on Kerbin without using parachutes, the parachutes can also be used if needed on Kerbin. If I was really low on fuel I could probably make a safe landing on Kerbin with the parachutes, with as little as 800 dv in LKO. I really wanted to do a Kerbin landing without using the parachutes though. Just needed to send a refueling tanker back up, no problem.

Edit: What I really need are 'grid fins'. I was planning on using the Airbrakes to add drag to the top of the Starship when performing landings. However, there are currently no deployable grid fins or airbrakes in the KSP2 game. I'm sure those are coming at some point, and will make life much better when doing stuff like this.

Edit#2: There was a lot of F5/F9 use during the completion of this challenge. Some of the screenshots are from flight segments which I had to go back and redo. In particular, the shot of the Starship leaving the launchpad is inaccurate. I only put one Kerbal in the capsule, instead of the 3 I had intended. Even worse was the fact that for some reason the ship in that screenshot didn't have a docking port when it got to orbit!! So obviously I had to re-fly that launch.

Edit #3: Just noticed there are no engines in the final screenshot, of the Starship sitting on the launch pad! I think I must have bumped them into the ground during the landing. Didn't even pay attention to that after the landing, was quite relieved to have touched down 'safely'. I did not see any explosions during the landing, but the only explanation I have for the missing engines is they must have contacted the ground pretty hard during the landing?

Poppa Wheelie · April 16, 2023

1 hour ago, 18Watt said:

The game thought my departure burn should be Duna prograde to get to Kerbin

This bug has been reported, and discussed elsewhere in these forums. I'm pretty sure it's universal for everyone attempting a return from Duna. I would be interested in hearing from anyone who has NOT seen this bug when returning to Kerbin from Duna.

18Watt · April 16, 2023

1 minute ago, Poppa Wheelie said:

This bug has been reported, and discussed elsewhere in these forums. I'm pretty sure it's universal for everyone attempting a return from Duna. I would be interested in hearing from anyone who has NOT seen this bug when returning to Kerbin from Duna.

I'm sure you know what I did- I F5's, and did the burn the way the maneuver node told me to. Knowing full well that it wouldn't work. Sure enough, didn't work.. So after F9ing, I just burned the way I knew would get me close. Really bizarre bug.

Little 908 · April 16, 2023

3 hours ago, 18Watt said:

Duna appears light blue/green in this screenshot.

Kinda looks like venus or titan, ngl kinda wish this wasn’t a bug lol

CptScience · April 16, 2023

I'd like to preface this with a disclaimer that infinite fuel was heavily abused during this flight, but otherwise everything ran without the need for extra mods! Here's a gallery of the whole mission

Jeb Level: Fly a Starship replica to orbit and land it propulsively at one of KSC's four landing pads

Using the largest sized components available, I made the Starship and Super Heavy stack as well as the launch mount. The booster has 34 engines: an outer ring of 16 Reliants and a series of inner rings of 18 Swivels. The Starship has three Mainsails as the "vacuum" Raptors and three Swivels for the sea-level Raptors.

After orbiting Kerbin, the Starship propulsively lands at the KSC

Meanwhile, the booster completed a boost-back burn using the inner engines

And used its gridfins for stability as it hit the atmosphere

Before finally touching down on the runway

Another great challenge! :happy:

Edited April 16, 2023 by CptScience
Added photos properly

Little 908 · April 19, 2023

I don't know why, but gliding a starship in ksp 1 was different. In ksp 2 all the starships I make flip over to land on the rear, while the ones I made in ksp 1 don't. Maybe it's because of the different wings, idk.

Makes it impossible for me to do a belly flop, or at least from what I have seen.

If you have a solution, please tell me

Beyond_Earth_Orbit · April 19, 2023

So not sure if this attempt counts as I ended up using the SORRY mod to get the gridfins in here, but I posted a OFT like video to my channel here:

and I will be posting (editing this post with updates) some additional videos completing the rest of the challenge with an all stock model that isn't quite so buggy.

In general would be really cool to have flaps that would enable belly flops to exist within the games physics. I know it's a stretch, but a Kerbal can dream right? :cool:

Little 908 · April 20, 2023

IT GLIDES :DDDDDDDDD

am I the first?

KerbalGuy89 · April 20, 2023

PyroSA · April 20, 2023

Apparently my horrid Starhip flights were at least more successful than the real thing.

This specific variant glides gloriously (and decomposes rapidly if I let SAS do its thing).

I did manage a few more technically impressive flights, but this one made an interesting spin...

KSP Weekly Challenge 8 - Imgur

Spoiler

Very basic first stage for testing.

Made it to space with a reasonable dV without need of refueling, perfect to try a landing.

The actual landing was not as successful though - Wings tend to rip off with large changes, and the SAS is all too happy to make such changes.
Here we are, spinning rapidly, but controlling the descent speed at least.

Manage to land 'gently' just off the coast of KSC.

I found that it glides fairly well, but all my attempts at getting it to survive flipping were unsuccessful so far.

If I pump all the fuel to the back it is surprisingly stable in reverse.

At least it got there and back?

FlyPathic · April 21, 2023

If anyone wants a pre-built starship, you can use the one I made!

Audaylon · April 21, 2023

Primary Objective Completed! Such a difficult challenge trying to replicate the star ship to scale!

Soda Popinski · April 21, 2023

Here's my attempt

Dunas Only Moon · April 21, 2023

I did this for the duna challenge...

MegaRouge · April 24, 2023

Here's my gallery for taking my Starship replica to the Mun and back.

https://imgur.com/a/jkRs53R

I haven't tried to build a replica of anything before so this was a fun challenge. I tried to be as true to life as I could but I also wanted a functional rocket, so I used 16 vectors on the bottom stage instead of 33 smaller engines that would not give me the thrust to take off. I added landing legs and ladders and stuck a big landing can in the payload bay and set out for the Mun.

This rocket flies amazingly well. I build so many giant abominations with hundreds of parts that I can barely get to orbit that flying this felt simple. The kraken liked to destroy Starship when I deployed the landing legs but I finally got it to work and landed, then headed for home. Landing on Kerbin was interesting, as this handles more like a plane than a rocket. I had a very ugly landing with some tumbling involved but managed to get it straightened out for a vertical landing in the ocean. I am sure with practice I could probably land this pretty well. Maybe I will go for the Val level and take this to Duna and back with refueling.

Edited April 24, 2023 by MegaRouge