Using the current version of KSP... If you had a Landing Pad near a Mun Base - Could you stick the landing?

[JoeSchmuckatelli]

I'm good enough to land in approximately the same crater as my other junk and drive / hop to it.  I'm certainly not good enough to plan a landing on a pad.  Or do it again if I managed it once.

 

So - is there a way to do this, reliably, that I'm just too nubish to realize / understand?

 

Also - another stupid question: Is there a way to know how different my speed would be at 40km pe coming in from a 90km ap, vs coming to the same pe from the Mun or Minmus?

Edited December 11, 2020 by JoeSchmuckatelli

[Beriev]

I may not be the best person to answer this one, but I feel like the problem boils down to that there's no way to see exactly where you will impact the terrain at any given moment in ship-view. I usually get around this by installing a mod that shows predicted landing location in ship-view; Trajectories, Mechjeb, and Engineer all seem to have this ability. Once you can see where you are going to impact versus where you want to actually land in ship-view, you can make course corrections while braking to fine tune your landing spot. This is the easy way out, but if you don't want to install a mod, an alternate solution may be just a lot of retries, learning each time you fail what not to do. I would not be the best person to ask as for said alternate solutions.

As for the second question, what I usually do to figure out how fast I'm going at apoapsis or periapsis is create a maneuver node exactly at that location, then only pull the retrograde modifier until the orbit is a line going straight down. The delta-V the node needs is usually decently accurate to figure out the velocity (albeit this only seems to work for orbital velocity at a location).

[Popestar]

If by "stick" you mean "land in a position relative to anything that is not on the landing gear, and doing so with a major explosion", then yes, I could "stick" then landing.

[Caerfinon]

I'm a fan of letting a mod stick the landing.  Lately I've been using Throttle Controlled Avionics for landing at bases on moons. It can set a craft down within 20 meters of target reliably... which I can not do

[Corona688]

I have reliably landed on docking clamps from orbit in the stock game, so yes, it is possible.

  I wrote a tutorial for how I do it.

On 1/16/2018 at 5:49 PM, Corona688 said:

When I do docking-from-orbit I do it in several phases.

1. Rough intercept, just by eyeballing and nodes in map view.  I don't aim to land on the target, as much as do a low flyover directly overhead which intersects the surface some distance past it.  This can get you within 10km, surface-wise.
2. Deceleration, killing much (though not all) of my velocity near/overtop the target.  I burn at 45 degrees or so, so I don't end up too short.  This is also a good time to correct your course if your direction is off.  Straight-line distance should be less than 5km now.
3. Sustain, pointing straight up and applying enough thrust to keep the prograde marker a little above my target.  This can get me within a hundred meters.
4. Hover, killing all velocity and getting my engines to as close to 1.0 local-g as I can manage.  (2020 note - use 'radial out' assistance in surface mode, if you have it!)
5. Docking, hovering on 1.0 local-g thrust and using RCS thrusters to move me around.  If the target isn't visible on navball you'll have to watch your RCS thusters in the live view and rough it in the right direction until it is.

Do yourself a favor and practice this on Minmus, where you can hover for tens of minutes at very little cost.

 

Edited December 11, 2020 by Corona688

[JoeSchmuckatelli]

On 12/11/2020 at 11:28 AM, Corona688 said:

I have reliably landed on docking clamps from orbit in the stock game, so yes, it is possible.

  I wrote a tutorial for how I do it.

 

That's quite interesting.  I've done a land randomly somewhere nearby and then hop to the destination - but what you describe looks to use more fuel than I usually have available. 

 

I wonder how they're going to do it in ksp 2.??

They keep showing bases and I can't imagine either being able to build one or not smashing into it if I did 

[Kerbart]

When landing close to another vehicle for reasons (rescue, base, science, etc) I always have to make sure I don't inadvertently land right on top of it. So yeah, totally doable.

[kerbiloid]

Maybe, TCA?

(Last updates are usually first published on the last page(s) of the thread).

[Vanamonde]

I have done stuff like this but I burn  excessive amounts of fuel in the process because I'm a nervous pilot and correct and correct and over correct. 

[Corona688]

5 hours ago, JoeSchmuckatelli said:

That's quite interesting.  I've done a land randomly somewhere nearby and then hop to the destination - but what you describe looks to use more fuel than I usually have available.

If you want to suicide burn onto a target, that will of course take computation assistance.  Not even NASA does real suicide burns, not unless they brought a crash barrier with them.

[Kosmix1]

With the mod kerbal engineer you can see a red spot on where you will end up landing.

I have also tried to land on a landing pad at the mun for my new base, its really hard and took me a lot of tries but its definitely possible.

[Vanamonde]

Question moved to Gameplay. 

[bewing]

There's a youtube video on how to do it, by Scott Manley, as I recall. You can do it if you can target it. You need to push your Retrograde marker on top of your Antitarget marker on your navball (target mode), just like you would if you were doing a docking.

[Wobbly Av8r]

Not trying to be a pessimist here - I'm all for the gung-ho, "let's kick some interplanetary butt here!" gameplay - but insinuating that using ~8 buttons (W,A,S & D, Q & E, along with Shift/Ctrl) loosely arranged into a logical flow pattern to enable precise three-dimensional maneuvers while utilizing a two-dimensional screen is, dare I say, "not likely to occur with any consistency".

The unmodified/lightly-modded gameplay pits the intense reality of orbital mechanics and precision maneuvering against the virtual reality of controlling the universe with a common keyboard.

I wouldn't take anyone's stories of heroics in replicating accuracy of landings as anything more than a "Well, that's nice".

Kerbal's didn't get their reputation for "on-the-fly engineering" for nothing, you know...

[linuxgurugamer]

3 minutes ago, Wobbly Av8r said:

Not trying to be a pessimist here - I'm all for the gung-ho, "let's kick some interplanetary butt here!" gameplay - but insinuating that using ~8 buttons (W,A,S & D, Q & E, along with Shift/Ctrl) loosely arranged into a logical flow pattern to enable precise three-dimensional maneuvers while utilizing a two-dimensional screen is, dare I say, "not likely to occur with any consistency".

The unmodified/lightly-modded gameplay pits the intense reality of orbital mechanics and precision maneuvering against the virtual reality of controlling the universe with a common keyboard.

I wouldn't take anyone's stories of heroics in replicating accuracy of landings as anything more than a "Well, that's nice".

Kerbal's didn't get their reputation for "on-the-fly engineering" for nothing, you know...

It’s difficult, but doable.  Repeatable with practice. Lots of practice. And when you think you had done enough, practice some more

[JoeSchmuckatelli]

Well - all of this is inspired by the images of KSP2 I keep seeing, showing large structures on offworld places.  Very curious about what this means for changes to game play.  As in - I don't think I could do it under the current flight rules - and given that difficulty is part of the fun in KSP... What changes are necessary for Neanderthal guys like me to progress in KSP2 to the level of building a methane mine? 

[Wobbly Av8r]

23 minutes ago, linuxgurugamer said:

It’s difficult, but doable.  Repeatable with practice. Lots of practice. And when you think you had done enough, practice some more

Indeed... You don't happen to have a room full of monkeys on typewriters clicking away in a room of your home, do you?

Having great respect for your contributions to this entertaining venue, I'll defer to your expertise!

In virtual reality, anything is possible - its just that some things are more possible than others.

As far as the OP is concerned, yes, building bases has been / surely will be possible, but given the known constraints, I'd anticipate having the ability to move any modules AFTER arrival, rather than plan that you'll be able to land them *accurately* into position...

[Zhetaan]

On 12/10/2020 at 9:49 PM, JoeSchmuckatelli said:

Also - another stupid question: Is there a way to know how different my speed would be at 40km pe coming in from a 90km ap, vs coming to the same pe from the Mun or Minmus?

It's called the vis-viva equation:

v² = μ [(2 / r ) - (1 / a)]

Where:
v = your orbital velocity
μ = the standard gravitational parameter of the body that you're orbiting (the body's mass times the universal gravitation constant--Kerbin's is 3.5316 x 10¹² m³/s²)
r = your current radial distance from the body (because of the way that KSP shows altitude, you need to add 600 kilometres--Kerbin's radius--to your sea-level altitude)
a = the semi-major axis of your orbit (that is the sum of periapsis + apoapsis + Kerbin diameter all divided by 2)

Comparing these is fairly straightforward:  since you want the speed at 40 km, the radial distance is the same in all three, as is the gravitational parameter.

For the semi-major axis, we can approximate it by saying that a return from a moon is equivalent to a return from Kerbin orbit at the altitude of the moon and use the moon's orbital altitude as the apoapsis for our semi-major axis calculation.

 

90,000 metre low Kerbin orbit:

(90,000 + 40,000 + 1,200,000) / 2 = a_LKO = 665,000 metres

12,000,000 metre Mun return:

(12,000,000 + 40,000 + 1,200,000) / 2 = a_Mun = 6,620,000 metres

47,000,000 metre Minmus return:

(47,000,000 + 40,000 + 1,200,000) / 2 = a_Min = 24,120,000 metres

 

And for the velocities:

Low Kerbin Orbit:

v_LKO² = 3.5316 x 10¹² [(2 / 640,000) - (1 / 665,000)]
v_LKO² = 3.5316 x 10¹² (3.1260 x 10^-6 - 1.503759 x 10^-6)
v_LKO² = 3.5316 x 10¹² (1.6222 x 10^-6)
v_LKO² = 5.7290 x 10⁶
v_LKO = 2,393.5 m/s

Mun Return:

v_Mun² = 3.5316 x 10¹² [(2 / 640,000) - (1 / 6,620,000)]
v_Mun² = 3.5316 x 10¹² (3.1260 x 10^-6 - 1.510574 x 10^-7)
v_Mun² = 3.5316 x 10¹² (2.9749 x 10^-6)
v_Mun² = 1.0506 x 10⁷
v_Mun = 3241.3 m/s

Minmus Return:

v_Min² = 3.5316 x 10¹² [(2 / 640,000) - (1 / 24,120,000)]
v_Min² = 3.5316 x 10¹² (3.1260 x 10^-6 - 4.145937 x 10^-8)
v_Min² = 3.5316 x 10¹² (3.0845 x 10^-6)
v_Min² = 1.0893 x 10⁷
v_Min = 3,300.5 m/s

Therefore, considering the 2,393.5 m/s return from 90 km to be the baseline, a return from the Mun would be 847.8 m/s faster, and a return from Minmus would be 59.2 m/s faster than that, or 907 m/s faster than baseline.  This should make sense; after a certain point, the apoapsis becomes some approximation of 'very far away' and tiny additions of delta-V change it dramatically, so the converse is true in that dramatic increases in apoapsis make only tiny changes to the velocity.  Also keep in mind that your actual results will vary:  you need to go through a lot of air to get to a 40 km periapsis.

[JoeSchmuckatelli]

@Zhetaan thanks very much for this!

[linuxgurugamer]

2 hours ago, Wobbly Av8r said:

Indeed... You don't happen to have a room full of monkeys on typewriters clicking away in a room of your home, do you?

How did you guess?  The secret is out:

 

[Corona688]

2 hours ago, Wobbly Av8r said:

Not trying to be a pessimist here - I'm all for the gung-ho, "let's kick some interplanetary butt here!" gameplay - but insinuating that using ~8 buttons (W,A,S & D, Q & E, along with Shift/Ctrl) loosely arranged into a logical flow pattern to enable precise three-dimensional maneuvers while utilizing a two-dimensional screen is, dare I say, "not likely to occur with any consistency".

KSP's controls really aren't that bad, and definitely aren't wrong in the technicals.  We had a trainee pilot credit KSP navball+docking for him acing his once-chance, fly-or-sink mid-air refueling simulation!

So yes, the existing stock controls, instruments, flight assistance, and map interface are quite enough for a practiced pilot to hit targets.

Which isn't to say there's no room for improvement.  I could make a thread on it.  I just might!

[18Watt]

Like @Kerbart, I'm in the camp where if I'm trying to land near something, I have to make sure I don't actually land on top of it.   It's not terribly difficult.   Learning to use the NavBall is essential (to me anyway).   I play stock KSP, so no mods are needed to land where you want to.

On the other hand, precision landings on Kerbin are a mystery to me, if I can get within 10km of KSC on return, well that's about as good as it gets with me.

[Wobbly Av8r]

8 hours ago, Wobbly Av8r said:

I wouldn't take anyone's stories of heroics in replicating accuracy of landings as anything more than a "Well, that's nice".

Okay, okay... a disclaimer: yes, I can occasionally put myself in a scenario that requires me to take measures to avoid my other-vessel target (but again, getting to this point would be nigh impossible if I didn't have KER "Show Target" enabled to determine when and how long to make my burns) so I willingly admit returning to the same general geographical area is doable with *some* effort, but despite the well-north side of 1,000 hrs of "practice", my SOP is unforgiving in its requirement for generous F5/F9 applications, and _uuuuusually_ a few "warm-up" attempts...

Now, I'm willing to pay penance by becoming one of the monkeys in @linuxgurugamer's basement, but even with that training regimen, hand-flying to the exact same "landing pad" and "sticking the landing", with identical orientation would still be a hill too far...

While I am impressed that you have been successful essentially combining the docking and landing maneuvers @Corona688 I'm assuming you do that with some level of modding and/or automation? I would be happy to know how to just accurately judge height and closure rate in the stock game much less deftly touching down at a rate that doesn't trigger a bounce off the target dock while fighting the local gravity well...

And I do appreciate your relating the story of the navball - as someone who used to be tested in a real "full motion" simulator, prepping mentally with these types of simulations is actually a bigger help than some might imagine! Kudos to the trainee!

Edited December 17, 2020 by Wobbly Av8r

[Wobbly Av8r]

After re-reading your explanation, @Corona688 I now understand what you meant by "getting my engines to as close to 1.0 local-g as I can manage", i.e. you cancel the gravity well with near exact offset thrust and then you've reduced most of the variables of the landing to make an RCS-guided "precision" landing. Kudos for the technique.

I'm still a little skeptical about the applicability to various size vessels (the more fuel burn is a percentage of the lander weight can affect how much time you have to dedicate solely to RCS maneuvering) and the rapid transition from needing high thrust settings getting tweaked accurately to a 1.0g thrust setting as all these events occur, but again, kudos!

[Spricigo]

important caveat