Need help on laythe ascent stage

[Mudkip909]

I'm building a rocket to laythe. but, I am making it where there is a mini SSTO in the cargo bay to go back to kerbin, just for a small challenge i am doing. but i have not built the lifter. can i have a hyperedit ship lander code for land? i need a large strip of flat land. help

[Vanamonde]

Maybe hyperedit to orbit and put a lander on it for the purposes of testing? 

[Mako]

For Laythe surface to orbit launches there's no need to hyperedit anything; just test from Kerbin. If you can get off of Kerbin at sea level you can get off of Laythe.

[Cunjo Carl]

On 4/15/2018 at 11:44 AM, Mudkip909 said:

I'm building a rocket to laythe. but, I am making it where there is a mini SSTO in the cargo bay to go back to kerbin, just for a small challenge i am doing. but i have not built the lifter. can i have a hyperedit ship lander code for land? i need a large strip of flat land. help

I'm a little late to the party, but Laythe's south pole is a great broad flat chunk of land that you can hit really easily from a polar orbit regardless of time of day. 10/10, would launch from southern polar region again.

[KerikBalm]

On 4/16/2018 at 2:01 AM, Mako said:

For Laythe surface to orbit launches there's no need to hyperedit anything; just test from Kerbin. If you can get off of Kerbin at sea level you can get off of Laythe.

Well, yes and no...

The requirements are quite similar, but they aren't quite the same. On the one hand it takes dV of a few hundred m/s less to achieve orbit, which means that you can build your ascent stage smaller if you are trying to optimize. Also, for rockets, the TWR on laythe is higher (since less gravity and less atmospheric pressure), so you can have a higher fuel/engine mass ratio (again, if you want to optimize). SSTO doesn't mean spaceplane, and doesn't mean airbreathing, so he could be using rockets for ascent.

If one uses airbreathers, the TWR may be a bit lower, because jet thrust decreases with air pressure, and 0.6 Atms vs 0.8 Gs mean that you could have only 3/4 the jet TWR on Laythe -but this depends on the engine, some deviate quite a lot from a 1:1 ratio of air pressure to thrust in particular the rapiers and whiplash.

Here's a plot of the date points for the engines:

although note that its really curves, not straight lines connecting the points, so the 0.6 atm value for the rapier in particular will be closer to 1 than it appears on the graph... the Juno to a lesser extent.

It was possible to build a micro SSTO and get to LKO with a Juno and spark in the past (but with very very small margins), but such a design easily gets to orbit on Laythe.

Example... this failed to make orbit, it would have on laythe:

This did make orbit, but barely... it would have a dV of hundreds of m/s left over if it was done on laythe, whihc would have allowed for actual landing gear (it had to use a launch trolley on kerbin, and land in the water, on laythe it could launch and land from the water, or it could use landing gear without becoming too heavy to make orbit)

Since he mentioned a mini-SSTO, when you try to go really mini, the differences between Laythe and Kerbin start to matter a lot.

[LoSBoL]

Have you got the Making History expansion?  If you do you can spawn a built (or build a) vehicle with a few clicks anywhere you want to. MH actually makes a great testbed.