Tylo Delta-V?

[fenderzilla]

How muchDelta-V does it take to to get from tylo's surface to orbit? i'm building lots of colonies and I need to plan an SSTO. I will have a refueling station in orbit AND on the ground, so I just to know how much is required to go between them.

[Diazo]

I use the chart from this thread.

I have not gotten that far out myself yet, but it say a delta-v of 3070 is needed, which should at least be close.

D.

[Mr Shifty]

Orbital speed for Tylo is very similar to Kerbin: about 2000 m/s at 100km orbit.

- To drop your periapsis to near ground level will take about 80 m/s.

- When you're near the ground, you have to kill your lateral velocity which will be about 2200 m/s. (The vessel will speed up as it descends.)

- While you're slowing, you have to fight gravity. If your TWR for the descent averages at 2, then about 13% of your thrust will be wasted on fighting gravity, so add 20-30% to your lateral velocity to account for gravity losses and safety margin: 660 m/s

Total: 80 + 2200 + 660 = 2940 m/s

Edited September 27, 2013 by Mr Shifty

[-Velocity-]

I created a few fully reusable, single stage Tylo landers and rocket rovers (rocket rover because why use landing legs when you could just use wheels instead and make a rover?). In my experience, it takes something like 5000- 5300 m/s of delta V to de-orbit, land, and re-orbit. You'll probably want to give yourself a safety margin and have at least 5600 m/s delta V. Also, make sure that the TWR isn't too low. I think my initial starting TWR (on Kerbin) for my landers/rocket rovers was about 1.4, peaking at a TWR of like 6 or 7 or something ridiculous like that.

Also, an important thing to keep in mind is that you might want to completely leave off RCS. It's a lot of weight, and you don't even need it if your mothership/tug in orbit has RCS itself.

Finally, if you want a Tylo lander with an actual lander cabin, you'll have to make it a lot bigger than if you just use the external chairs. If you're going without an actual cabin, you can make your lander a lot smaller and consume a lot less fuel.

Oh and finally, yes I used mods- KW rocketry's Vesta engine in particular. However, IIRC, it's possible to do all this without mods- you'll need to use high Isp, high TWR engines like the LV-T30 or LV-909, and you'll have less of a spare delta V cushion than if you used KW rocketry Vesta engines. And you'll probably almost certainly have to go without RCS on your lander, where with the KW Rocketry Vesta engine, you certainly can put a bit of RCS on your lander if you're willing to sacrifice some of your delta-V cushion.

Edited September 27, 2013 by |Velocity|

[Geschosskopf]

The interesting thing about Tylo is that it costs considerably more fuel to land there than it does to take off again, due to its high gravity and no atmosphere. You have to burn nearly all the way down to avoid splattering, and this is happening while your ship is still full of fuel so each unit of fuel burned produces less change in velocity. But assuming you survive the landing, getting up again is a cakewalk in comparison. Your ship is now much lighter (you probably burned about 2/3 of your fuel during the descent) so accelerates like a champ, and you can lean over and burn close to horizontally as soon as your legs leave the ground, so you have a more efficient flight path going up than you had coming down. And all you have to do is reach about 20km to be above all the mountains, after which it's just a matter of meeting up with a flying fuel tank.

Because of this, it's actually possible to make relatively small Tylo landers and even use nuclear engines on them. You just have to start from an orbit high enough that the increasing TWR as you burn fuel has enough time to act, given that nukes have low thrust to begin with.

For example, this little 1-man lander (the part to the left of the docking port) can safely land starting from 200km and return to 40km, but starting any lower and it lithobrakes, and starting any higher and it burns too much fuel to reorbit .

[Moar Boosters]

The descent stage probably has way to much delta V, but I don't use mechjeb for the landings and I'm not a very good pilot, so I give myself loads of margin for error. As you can see... the ascent stage is tiny, but was more than enough for the job.

[fenderzilla]

I'm planning to have a base on tylo as I mentioned before - let's assume i am fully fueled when I take off. how much Delta-V do I need then?

[Geschosskopf]

I'm planning to have a base on tylo as I mentioned before - let's assume i am fully fueled when I take off. how much Delta-V do I need then?

It depends on how high you want to go. 20km is about the lowest safe orbit at Tylo and the map says that needs 3070m/s. I've done it with 2800m/s IIRC but that was directly on the equator from a medium-high elevation plateau and I didn't have to climb steeply over any nearby mountains so could fly as close to horizontally as my TWR allowed. If you go higher, start lower, or have a mountain inconveniently close downrange, it costs more. So 3500 should be a good ballpark figure, which you can adjust up or down as needed after some tests.

[Moar Boosters]

You should be good with 3500. The little pod on the top of my lander had 3400 and was able to reach a 50km polar orbit and still had enough for the rendezvous.

[fenderzilla]

just 3500? that seems surprisingly little... well, alright. i'll give it a try.

[-Velocity-]

Ermm... 3500 seems a little extreme to me, unless your TWR is real low. With a high TWR, you will have very little gravity drag, and honestly, I would be surprised if you couldn't get to orbit with just like ~2500 m/s. I'm pretty sure, if I remember correctly, my Tylo lander got back up to orbit using that much or even less. But half its fuel was already consumed at its TWR was like 3 (on Kerbin).

[Iansoreta]

Oh man, this thread is getting old. I don't see anything new about this thread, so someone close this thread.

[magnemoe]

How muchDelta-V does it take to to get from tylo's surface to orbit? i'm building lots of colonies and I need to plan an SSTO. I will have a refueling station in orbit AND on the ground, so I just to know how much is required to go between them.

As other says you need more fuel landing, I would like to go up towards 3500 m/s you have no abort options here and have to land pretty close to the depot too.

[Mesklin]

Minmal theoretical dV for Tylo landing/ascend from 30 km round orbit is 2221 m/s and with good TWR (>2 on start) and very good piloting skills you can spend only 2300-2400 m/s for landing and 2300 for ascent. But it should be realy good piloting skills. For more safe landing and with margin for precision landing you should make 3000-3500 m/s dV with start TWR as minimum 1.5 (2 will be better). Best landing sequence is make orbit with periapsis 7-8 km and start deorbit burn near periapsis, you should kill horizontal speed as close as possibly to surface (ideally - 100-200 m from surface) .

[Vanamonde]

This indeed a year+ old thread. Thank you for pointing that out, by posting in it. Closed.