High Points for Maximum Coverage

[Mars-Bound Hokie]

I made this high-power surface relay craft (~500G of coverage) that I can land on any moon/planet (picture below). While it may be useful for providing relay coverage to spacecraft that are blocked from the orbiting relays, I think it can be just as useful for surface vehicles as well.

• DISCLAIMER: The current design is only meant for non-atmospheric planets. I'll need to change it for places such as Eve, Laythe, and Duna.

 

Does anyone have a list of coordinates for the highest elevation points on all the celestial bodies in the Kerbol system - as well as their elevation above sea level? I want to be able to provide maximum surface coverage from the high ground, just like a cell tower. 

• Craft file available upon request for just 331,552 a launch. It may look expensive, but it's worth the money considering the immense relay power and delta-V capacity. It's already made it to Eeloo so far.

 

Thank you.

[Geschosskopf]

1 hour ago, Mars-Bound Hokie said:

I made this high-power surface relay craft (~500G of coverage) that I can land on any moon/planet (picture below).

Well, that certainly looks impressive, but I have to ask..... WHY? Ground relays are inherently useless.  The ONLY reason to have relays is to provide links around planetary bodies that block the direct line back to Kerbin (OK, and also to boost signal strength but, without being about to see around blocking planets/moons, that's moot).  A relay on the ground is by definition tied to its body's rotation.  Thus, a ground relay is of no help AT ALL in getting around blocking bodies.  If the ground relays are facing Kerbin, then any ship they can link to ALSO has a line to Kerbin and doesn't need them.  If they're facing away from Kerbin, then they're totally useless.

Seriously, for a lot less money and trouble, you can put a pretty minimal relay network in space.  Every planet except Moho gets a pair of relays in highly eccentric (like nearly to the edge of SOI) polar orbits 180^ out of phase with each other.  Every moon of those planets where you want to do something that might be on the far side needs 1 (or at most 2) small relay in equatorial orbit big enough that the polar relays of the primary planet can see over the moon to them.  And that's it.

Again not considering signal boost, you only need a comm link to:

1. Transmit science
2. Access Kerbnet
3. Control probes if you have that setting enabled

#1generally doesn't require a relay unless you've put a 1-way probe lander on the far side of Mun or something similar, so the ONLY way data can get back is transmission through a relay.  Which MUST be in space because if it's on the ground, it can't see Kerbin, either.  If the ship is in space or will soon take off again, then it can wait to transmit until it has its own clear shot back to Kerbin.

#2 and #3 for the far side of whatever body are covered completely by the minimal system described above.  Ground-based relays do not help this in the slightest.

Edited July 10, 2019 by Geschosskopf

[KerikBalm]

1 hour ago, Geschosskopf said:

WHY? Ground relays are inherently useless.  The ONLY reason to have relays is to provide links around planetary bodies that block the direct line back to Kerbin (OK, and also to boost signal strength but, without being about to see around blocking planets/moons, that's moot).  A relay on the ground is by definition tied to its body's rotation.  Thus, a ground relay is of no help AT ALL in getting around blocking bodies.  If the ground relays are facing Kerbin, then any ship they can link to ALSO has a line to Kerbin and doesn't need them.

I disagree. Kerbin's relays are by default 250G at level 3. You can get much more powerful than this. Ground relay are useful because its easier to do this:

than this (which is weaker)

Furthermore, relays always in the same position relative to the surface are useful. Consider landing on Duna. One side always faces Ike. If you put a ground relay on Ike, you always have a link to it. When its night time (ie facing away from the sun, and thus away from Kerbin), you can still bounce off of Ike to reach kerbin. 1 Relay instead of a network. Its similar with GSO, but as in the Duna-Ike case, sometimes GSO is occupied, in which case you can make it a ground relay.

Also, when you have a surface base, or deploy a rover, maybe the rover can't connect directly, but if your dropship/transport has a relay (I often add HG-5s or RA-2s), then the dropship serves as a ground relay for the duration of the excursion.

[Mars-Bound Hokie]

@Geschosskopf and @KerikBalm, you both present compelling arguments.

 

I'll start with @Geschosskopf (since s/he replied first). Though surface relays may not be as effective as orbital relays, they still have some purpose.

13 hours ago, Geschosskopf said:

If the ground relays are facing Kerbin, then any ship they can link to ALSO has a line to Kerbin and doesn't need them

Not necessarily. The ship in question may not be able to reach Kerbin on its own due to its antenna being too weak (assuming it has one), and/or the orbital relays may be on the other side of the planet (or too weak, depending on the design/orbital position/planet). 

13 hours ago, Geschosskopf said:

If they're facing away from Kerbin, then they're totally useless.

Maybe, maybe not. Due to this particular relay's immense power, it's bound to hit another relay - either orbiting its host planet or positioned millions of kilometers away. Even if they're unable to reach Kerbin, they still have solar panels and RTGs to supply it with enough power to last forever. They should be able to reconnect to Kerbin any minute (or hour or day, depending on the planet's/moon's rotational period). 

13 hours ago, Geschosskopf said:

Seriously, for a lot less money and trouble, you can put a pretty minimal relay network in space

That's what I thought when I started playing a "Practice" sandbox. One or two orbital relays orbiting the planet - even the Ultimates - weren't good enough. My probes/remote-controlled ships kept getting cut off due to the relays being on the other side of the planet; when I sent a surface relay, they got cut off less frequently.

• Besides, there's no such thing as too strong a network coverage in KSP. 
  • And not all moons have geostationary orbits. Even if they did, like you said earlier, they can be rendered useless when they're pointed away from Kerbin.

Apart from that, surface relays can be especially helpful for surface ops (e.g. rovers, unmanned mobile bases, remote-controlled outpost deliveries, etc). That's why I wanted a list of high points in the Kerbol system in the first place, to maximize coverage.

 

Now, on to @KerikBalm. While that is an impressive mobile surface relay you have there (and at 2,500G), how are you going to get it to other planets/moons? Besides, I don't think you need that much power just to provide a link back to Kerbin from anywhere in the Kerbol system. The satellite seems like a more realistic option for larger/far-away places like Jool and Eeloo. I really liked your example on positioning a surface relay on Ike (since it's pretty much in geostationary orbit around Duna) to provide coverage for surface ops on Duna - provided they have a powerful enough antenna to reach the relay. 

• For all my Wally rovers, I equip the drop capsule with an RA-15 relay and solar panels so that the robot can connect with Kerbin if the antenna's not working (e.g. it's destroyed or I forget to turn it on). Besides, it can provide network coverage for any other surface vehicles close by to the drop zone.

 

All pro/anti surface relays arguments aside, I need a list of the high points of all the planets/moons in the Kerbol system. If not to position surface relays there, at least I can get some nice views/science gains from there.

[Cavscout74]

Take a look here:

 

 

[mystifeid]

21 hours ago, Mars-Bound Hokie said:

I made this high-power surface relay craft (~500G of coverage)

 

5 hours ago, Mars-Bound Hokie said:

Now, on to @KerikBalm. While that is an impressive mobile surface relay you have there (and at 2,500G)

For future reference, combining antennae provides diminishing returns.

[Geschosskopf]

18 hours ago, KerikBalm said:

I disagree. Kerbin's relays are by default 250G at level 3. You can get much more powerful than this. Ground relay are useful because its easier to do this:

than this (which is weaker)

But, you're assuming you're talking direct from Kerbin to Jool or wherever your distant ship is.  Why would you ever do that?  At some point on every interplanetary trip, usually close to arrival there, the sun will be in between Kerbin and the destination.  So just put a pair of relays at every main planet except Moho.  Most of the time, you only have to cross from 1 orbit to the next per link, 2 at most on a very rare inconvenient alignment of the spheres, so you need way less power and range per relay.  And this also gives you multiple possible paths to talk around the sun.

 

18 hours ago, KerikBalm said:

Furthermore, relays always in the same position relative to the surface are useful. Consider landing on Duna. One side always faces Ike. If you put a ground relay on Ike, you always have a link to it. When its night time (ie facing away from the sun, and thus away from Kerbin), you can still bounce off of Ike to reach kerbin. 1 Relay instead of a network. Its similar with GSO, but as in the Duna-Ike case, sometimes GSO is occupied, in which case you can make it a ground relay.

Ike is only visible from about 1/4 of Duna's surface (at most) so putting a ground relay on the Duna-facing side of Ike does zero good elsewhere on Duna.  And the Ike ground relay only has an LOS back to Kerbin for the small fraction of the Dunan day between when it can see past the edge of Duna to Kerbin and is not yet blocked by Ike's own horizon.  So maybe a total of about 120^ out of the 360^ (divided into 2 separated bits of about 60^) that make up a Dunan day.  IOW, a ground relay on Ike provides coverage for less than half of Duna less than half the time.  Not a good deal.

Whether it's day or night on Duna has no bearing whatsoever on whether Ike has an LOS back to Kerbin.  Duna has a long day that Ike syncs with, and Duna has a different orbital period than Kerbin.  Thus, the angles between them are nowhere near constant, and this is even without the sun coming in between them, which it will surely do at some point in the mission.  It's as likely as not for it to be daylight on the side of Duna facing both Ike and Kerbin, and in that case Ike has its back to Kerbin so a ground relay there is blocked.  Likewise, it can easily happen than the Ike- and Kerbin-facing side of Duna is in darkness, so again Ike has its back to Kerbin.

 

18 hours ago, KerikBalm said:

Also, when you have a surface base, or deploy a rover, maybe the rover can't connect directly, but if your dropship/transport has a relay (I often add HG-5s or RA-2s), then the dropship serves as a ground relay for the duration of the excursion.

Or maybe you just have a small relay (or 2 at most) in equatorial oribt that talks over the moon's pole to the relay in polar orbit of the primary, which then links through however many similar relays at other planets back to Kerbin.  If you're doing Apollo-style, the orbiting part of the mission can be that equatorial relay.

 

6 hours ago, Mars-Bound Hokie said:

Not necessarily. The ship in question may not be able to reach Kerbin on its own due to its antenna being too weak (assuming it has one), and/or the orbital relays may be on the other side of the planet (or too weak, depending on the design/orbital position/planet). 

This (besides covering the far side) is why you put equatorial relays where you want to land, that link to the main polar relays.  Even the weakest direct antennae can reach the equatorial relay, which then can reach all the other relays back to Kerbin.

6 hours ago, Mars-Bound Hokie said:

Maybe, maybe not. Due to this particular relay's immense power, it's bound to hit another relay - either orbiting its host planet or positioned millions of kilometers away. Even if they're unable to reach Kerbin, they still have solar panels and RTGs to supply it with enough power to last forever. They should be able to reconnect to Kerbin any minute (or hour or day, depending on the planet's/moon's rotational period). 

There is no such thing as a comm network that provides coverage 100% of the time to 100% of every planet.  it doesn't matter whether you're on the ground or in space, every once in a while, every other planet will align on the opposite side of the sun from Kerbin.  This is the worst-case scenario for a space-based relay system.  And it's the only point of failure.  With ground-based systems, not only do you have this, you also have the much more frequent situations where every planet has its back to Kerbin even if the sun is not in the way.

Fortunately, you don't ever need anything close to 24/7 coverage everywhere.  You only need comms at a few specific points in any mission, maybe 1% of the total MET of an interplanetary trip.  And it's a lot easier, and more reliable, and cheaper, to do this with orbital relays than ground-based systems, most of whose capacity is wasted most of the time.

 

6 hours ago, Mars-Bound Hokie said:

That's what I thought when I started playing a "Practice" sandbox. One or two orbital relays orbiting the planet - even the Ultimates - weren't good enough. My probes/remote-controlled ships kept getting cut off due to the relays being on the other side of the planet; when I sent a surface relay, they got cut off less frequently.

Well, that's your own fault for arranging your probe to be where comms were not

The 1st thing that should go to any planet are the relays for the highly eccentric polar orbits of the main planet.  You already have similar things back at Kerbin so these should always have control when they need to maneuver.  Once in place, not only do you have a link from this planet to Kerbin free of any intervening moons, but these relays also cover nearly all of the main planet's surface, all of its SOI, and somewhat more than the facing sides of any of that planet's moons.  So for most of what you can do in that planetary system, you're already set.  You just need an equaltorial relay or 2 to fill these small gaps if you're going there, and then time your maneuvers to coincide with when you have coverage.  Easy peasy.

6 hours ago, Mars-Bound Hokie said:

• Besides, there's no such thing as too strong a network coverage in KSP. 

Sure there is.  99% of the time, you don't need it at all.  

6 hours ago, Mars-Bound Hokie said:

Apart from that, surface relays can be especially helpful for surface ops (e.g. rovers, unmanned mobile bases, remote-controlled outpost deliveries, etc). That's why I wanted a list of high points in the Kerbol system in the first place, to maximize coverage.

Again, 99% of the time, you don't need comms.  And there's no hurry to surface ops.  So just wait until an equatorial relay comes over the local horizon.  If you don't want to wait, put 2 equatorial relays evenly spaced there, so you should almost always have 1 above the horizon.  Using 3 is overkill--you get 24/7 coverage when you don't need anything like that

[18Watt]

As to the original question, here is a site which shows you the highest point and lowest point for each body:  https://ksp.deringenieur.net

Once you have selected a planet or moon, in the options button select 'Points of Interest'.  For the few bodies I looked at, that selection displayed the high and low points.  However, it appears to me the lowest point may be the deepest part of the ocean for bodies with liquid covering some of the surface (Eve, Kerbin, Laythe).  It sounds like you are more interested in the high points anyway.