KE37-Overkill Kerbin remote tech constellation

Goal

We want to provide a connexion to ALL planets orbiting Kerbol, to moons of Kerbin  and add a manageable connexion for emergency or ongoing missions.

3 sats in equatorial orbit at 1 581.76 and 2 sats in polar orbit. Why 1 581.76?

because it’s a semi-synchronous orbit on Kerbin

A semi-synchronous orbit with an orbital period of ½ of Kerbin’s rotation period (2 h 59 m 34.7 s or 10774.7 seconds) is achieved at an altitude of 1 581.76 km with an orbital velocity of 1 272.28 m/s.

Ksp wiki

Why a semi-synchronous orbit? WHY NOT? Well, we need to determine an altitude, A geostationnery orbit is impracticable we will need 6 sats instead of 5 to work. Rated at 220000 Kesos each sat (sat only, launcher not included) 5 is better than 6…

Screen Shot 2017-01-25 at 18.32.57.png

We want to provide a connexion to ALL planets orbiting Kerbol, to moons of Kerbin  and add a manageable connexion for emergency or ongoing missions.

Antennas selection for each celestial

Planets

We need the max distance but also the min distance to know if the cone range of a dish is ok.

Kerbin: Apoapsis = Periapsis =13 599 840  km

max distance to planet : on opposite side of the sun, planet at apoapsis.

min distance to planet : on the same side of the sun, planet at apoapsis for inner planets, planet at periapsis for outer planets

Apoapsis Periapsis Min distance Max distance
Moho 6.315.765.980 4.210.510.628 7.284.074.276 19.915.606.236
Eve 9.931.011.387 9.734.357.701 3.668.828.869 23.530.851.643
Kerbin 13.599.840.256 13.599.840.256
Duna 21.783.189.163 19.669.121.365 6.069.281.109 35.383.029.419
Dres 40.839.348.203 34.917.642.714 21.317.802.458 48.517.482.970
Jool 72.212.238.387 65.334.882.253 51.735.041.997 78.934.722.509
Eeloo 113.549.713.200 66.687.926.800 53.088.086.544 127.149.553.456

Moho

Screen Shot 2017-01-25 at 19.40.59.png

Eve

Screen Shot 2017-01-25 at 19.40.59.png

Duna

Screen Shot 2017-01-25 at 19.43.05.png

Dres

Jool

screen-shot-2017-01-17-at-19-12-57

Eeloo

Eeloo is a special case. The comtech need to be at least at 67Gm to see a keosynchronous orbit, we won’t deploy the constellation at a keosync altitude but not so far: we need to use 2 dishes for it.  (the reflectron gx128 is worst)

Commtech 1 for long distance ranging from 67Gm to max distance.

screen-shot-2017-01-17-at-19-12-36

Ra-100 for “short” distance ranging from 58Gm to 67Gm

screen-shot-2017-01-17-at-19-12-57

Moons of Kerbin

We also want to reach Mun and Minmus in Kerbin SOI.

Mun

With an apo and a peria of 12 000km, a HG5 is a perfect match

Screen Shot 2017-01-25 at 20.02.20.png

All relays will be equipped with a Comm32 which has a 5000km range. The network will be deployed at 2000km. The minimum range of this antenna is 3500km. We won’t risk a blackout.

Minmus

Screen Shot 2017-01-25 at 20.05.37.png

Other moons

All other moons won’t be reachable directly from Kerbin, they’ll use the relays network of the planet they are orbiting.

Disposable connexions

i want to be able to connect a vessel on the fly everywhere in the Kerbin system. And for this, it seems i need almost all dishes to cover the full range…

Range 81000M – 400000M

Screen Shot 2017-01-25 at 20.11.24.png

Range 17000M – 81000M

screen-shot-2017-01-17-at-19-12-57

Range 3400M – 17000M

screen-shot-2017-01-25-at-19-40-59

Range  1700M – 3400M

Screen Shot 2017-01-25 at 20.26.08.png

Range 200M – 1700M

This range is problematic because any antenna can fit it. In this situation, we will have to connect a direct relay instead of the constellation.

Range 32M – 200M

Screen Shot 2017-01-25 at 20.38.13.png

Range 8500K – 32M

screen-shot-2017-01-25-at-20-05-37

Range Kerbin – 8500K

screen-shot-2017-01-25-at-20-02-20

Well, i never said it will be an economical solution With such a number of dishes, i don’t know if we can still call these sat relays… They will be big…

We need to check the electrical consumption, which will be high….

Electrical consumption

  • gx128 *1
    •  EC2.80
    • disposable
  • comtech * 1
    • EC2.60
    • Eeloo
  • ra100 * 3
    • EC1.10*3 = 3.30
    • Jool, Eeloo, disposable
  • kr14 * 1
    • EC0.93
    • Dres
  • comm88 * 1
    • EC0.93
    • Duna
  • hg55 * 3
    • EC1.04*3 = 3.12
    • Moho, Eve, disposable
  • ra15 * 1
    • EC1.10
    • disposable
  • ra2 * 1
    • EC1.15
    • disposable
  • hg5  *2
    • EC0.55*2 = 1.10
    • Mun, Minmus, disposable
  • dts1 * 2
    • EC0.82*2 = 1.64
    • Minmus disposable
  • Com32 * 2
    • EC0.60*2= 1.20
    • Internal
  • Dp10 * 1
    •  EC0.01
    • Internal
  • Total                        EC20 /Sec

Rounded to 21 (only for antennas) we need at least:

Screen Shot 2017-01-25 at 21.16.28.png

Deploying the constellation

screenshot5

First, we deploy the first polar relay at 1581.7km ASL. Unfortunately due to the size of the relay, it’s not possible to do a multilaunch deployment.

screenshot4

The relay is mounted backward in the fairing to streamline the rocket as much as possible to minimise drag.

screenshot3

The first one is launched  at 250km ASL, The second stage still attached is used to bring the relay at an apoapsis of 1581.7kmASL

The relay uses its 6 ion powered engines to achieve an orbit at 1581.7km.

 Orbit is tweaked to match an exact inclination of 90° and an orbital period of 2 h 59 m 34.7 s.

Screen Shot 2017-01-26 at 16.43.36.png

For the second one, we wait for Ksc and the orbit of the first one to be aligned. We launch the second one. We match inclination as soon as we are in orbit.

Next, we add a manoeuvre node to do a Hoffman transfer without executing it. We add to the node time the offset (1731sec) provided by the visual remote tech planner. (launch alt start; 250km, orbit destination 1581.7. This way our relays will be exactly on the opposite side of Kerbin. This tool also tells us we will need 407m/s for the Hoffman transfer and 319 for final circularisation. Finally, we perfectly tweak our orbit to match plane of the first relay and achieve an exact 2 h 59 m 34.7 s orbital period.

All antennas are oriented to their respective target, all disposable antennas are set to off. (

At this time the two polars relays are deployed. Still 3 relays to deploy on an equatorial orbit. The procedure is exactly the same except we don’t have to wait for KSC to match the inclination of the first sat and the slide value is different because we are launching three sats.

Costs

Each relay and launcher cost 401k. I have a commercial strategy on the administration building which gives me a 9% reduction, i pay only 360k each sat. I need 5 of them.

With stage recovery, i recover the 2 boosters and the first stage. I recover only 25% of the cost of a booster but it’s only a booster… For the first stage, i recover 51k of the 55k. 55k is the cost of the first stage without fuel.

For the second stage, i operate a manual deorbit, i recover about 60k.

So, 360  -55 -60 = 245k

245k*5 = 1225k.

The constellation costs 1,2 million, which is acceptable for such a network able to connect the whole system in realtime.

screenshot16screenshot8

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