Landing danger?

[MaxwellsDemon]

When trying to land at an already-established site, such as a Munar base, how real are the chances of accidentally coming down on top of something that's already there? Given that trying to hit an exact point is difficult, so it shouldn't be an every-day occurrence... but if I were to, say, mark off an area for a landing zone, how far away from the established base structures would I want it to help avoid accidents?

I'm thinking primarily in terms of the MechJeb autoland targeting, but also in a larger, non-MechJeb sense...

Edited October 30, 2015 by MaxwellsDemon
Switching to Answered

[Tex_NL]

MechJeb can be extremely accurate. I have had MechJeb literally knock off solar panels of targeted craft. In other cases MechJeb struggled to land within a few hundred metres.

I get my best success by entering the coordinates of an area known to be clear (walk a Kerbal to a clear area, switch to map and call up the info screen to write down the coordinates) instead of targeting a surface base. But I always keep RCS at the ready to make final adjustments in case MechJeb is off.

[MaxwellsDemon]

I get my best success by entering the coordinates of an area known to be clear (walk a Kerbal to a clear area, switch to map and call up the info screen to write down the coordinates) instead of targeting a surface base.

Yeah, that's sort of what I had in mind... basically to identify a landing zone with three or four flags, calculate the mutual center, and aim for that. Just trying to figure out how big I should make the zone and how far away from the base.

[Racescort666]

When I was playing with MechJeb, Mun landing is very accurate as long as you're in a moderately high and fairly circular orbit. I know there's been some updates since I stopped playing with MechJeb so it might even be better.

That being said, now that I'm not playing with MechJeb, my preferred method for airless body landings is to come in super low and basically burn horizontal until the last second. I've had very good luck with this and have landed fairly accurately next to other spacecraft. MechJeb is a lot better at suicide burns than I am though.

Also, regarding calculating the center of the landing zone, just plant a flag there. You can target it to help you with manual landings if you are so inclined.

[Tex_NL]

Don't target a flag directly or you'll risk landing on top of it, toppling your lander.

[kerbiloid]

1. Process your landing with MechJeb.

2. When you're 50..100 m over you destination site, open MechJeb's window "Translatron", abort the "Landing" and enable Translatron's "Keep Vert".

3. While Translatron keeps your vertical speed -1..-2 m (enter at your wish), move in the desired direction to avoid collisions and to put your lander at the desired point.

4. Land. Switch off.

[magnemoe]

Mechjeb is very accurate landign on places with medium gravity with an lander with decent twr.

On low gravity places, lower than minmus or with very high relative twr is tend to mess up going into final decent.

Else it tend to land iside

First I plant flags to indicate landing zone, use this as target not you base. Say 25 meter from solar panels.

On final decent I use rcs to adjust, one issue with high locations is that mechjeb might auto warp from 500 to 200 meter or something.

Disable this if an problem,

on small landers without rcs I tend to just disable the autopilot but have is showing landing location then do sideway burns to adjust before activating it again.

[Acet]

Aim at the base, do the final adjustment yourself.

I personally do all landings by hand, tough I use KER to be able to see things like actual distance to the ground and distance to suicide burn point, so as to avoid wasting too much fuel.

The secret with final adjustment is to make your base (or a flag, landed ship or kerbal) a target and then try and get the target's prograde indicator to be right on the centre of the blue part of the navbar - which means you're right on top of it - and at that point kill horizontal speed and drop. Once closer to the ground it will start drifting so adjust with horizontal speed to keep it centred. The last bit of adjustment can be done visually when you're close enough.

Works fine in Minmus (where you can train this with little risk) and is a little harder on the Mun but not that hard to do (I have bases on both and always land manually).

Outright crashing is very rare unless I'm trying some kind of daredevil manoeuvre (like trying to time my burn down to the last second), but it's possible to end up a bit too far from the base if low on fuel (which is a frustrating waste of time due to me having to send a ship or rover to refuel) or do a silly mistake like clipping a solar panel on the base, so I usually quick save before doing a landing from orbit, though less often when just doing suborbital transfers.