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Satellites?


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I'm going through career mode, and I'm about to get my first Kerbal into LKO to satisfy that contract, and I asked myself if I should put a satellite into orbit instead.  I could launch and leave it there, and the contract would be satisfied.

But then I asked myself what value that would provide.  Is there some advantage to using unmanned probes in orbit?  Is there something they can do that manned pods cannot?

So I ask the community here what the advantage to a satellite might be.  Why would I use an unmanned pod, and under heat conditions would one be preferred to a manned pod?

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Leaving aside the funds and rep, for lko -> hko not much. The ground stations will cover much of that volume. Though if you do not have multiple station enabled the reason for satellites is obvious.

For munar and minion orbit, the reason for sats is to cover the darkside.

As for kerbbed vs unkerbbed… I've always gone with unkerbbed. I save my kerbals for ships, stations and bases.

As grammatical aside... is it kerbbed or kerbed?

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Advantages of sending a crewed pod or mission:

  • More science can be gained directly, through EVA and crew reports, surface samples and some Breaking Ground surface features that can be picked up, and indirectly through bringing materials bay and mystery goo samples back. There’s also the mobile lab that can generate a nearly infinite amount of science by processing science data even if you’ve already returned 100% value for that experiment to the surface, and scientists can reset materials bays and mystery goo cans to use them again as well as collecting data from any science experiment part.
  • More achievements for doing EVAs, crew transfers and planting flags.
  • The ability to deploy Breaking Ground surface experiments which slowly gather science over time.
  • At least partial control under all circumstances (only matters with CommNet on).
  • Levelling up Kerbals to make them better at doing stuff (pilots get more SAS modes, engineers can repair things and scientists get more science from flights).

Disadvantages of sending a crewed pod or mission:

  • They’re heavier, so require more fuel to go places.
  • They’re more expensive, plus the extra fuel needed makes them even more expensive.
  • If using a life support mod, you have to make sure they have enough supplies for the trip or they could die.
  • The risk of killing or stranding the crew if you make a mistake (although there are no penalties for killing Kerbals in the stock game, it’s generally frowned upon to not bring crews back from space- preferably alive!)

Advantages of using probes:

  • Cheaper than crewed missions.
  • Can be sent one way without anyone caring (nobody is complaining that those Mars rovers will never come back to Earth).
  • Probes tend to be much smaller and lighter, making them easier to launch and needing less fuel to get to their destination.
  • Can carry relay dishes to boost communications (only if CommNet is on).
  • Can be booted on to the side of a crewed mission then dropped off at the destination to act as relays, gather science etc.
  • Almost all probe cores have SAS in them to stabilise the craft, and some come with upgraded versions allowing direction holds (pro/retrograde etc.) which pilots need to be levelled up to do and other Kerbals can’t do at all.

Disadvantages of probes:

  • You can’t get as much science from a probe.
  • With ‘require signal for control’ you need a CommNet signal to have any control at all over it; with that option off but CommNet on you still can’t fully control a probe without a signal.
  • Some probe cores don’t have built-in reaction wheels or even SAS (looking at you, Stayputnik) so can be harder to fly.
  • Probe cores use power constantly and most have tiny built-in batteries; run out of power and a probe is totally useless, and it’s easy to forget to deploy solar panels or have them facing the wrong way. Solar panels also unlock later on the tech tree than the earliest probe cores so unless you have them unlocked they will quickly end up dead.

@steuben I dodge that issue by calling it ‘crewed’.

Edited by jimmymcgoochie
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1 hour ago, Popestar said:

Well, it isn't so obvious to me, which is why I asked.

If you do not have multiple ground stations on Kerbin, and you have CommNet turned on in your settings, then any robotic probe will lose communication under most circumstances and all robotic probes will be very difficult to control. Playing under those settings pretty much requires you to build a satellite communication relay network. In fact, that's why players choose to play with those settings turn on. In which case, the reason to put up a satellite is indeed pretty obvious -- because you need to put a relay antenna on it to establish a communication network.

Edited by bewing
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2 hours ago, bewing said:

If you do not have multiple ground stations on Kerbin, and you have CommNet turned on in your settings, then any robotic probe will lose communication under most circumstances and all robotic probes will be very difficult to control. Playing under those settings pretty much requires you to build a satellite communication relay network. In fact, that's why players choose to play with those settings turn on. In which case, the reason to put up a satellite is indeed pretty obvious -- because you need to put a relay antenna on it to establish a communication network.

That is what I was after - the reason behind using satellites.  It makes perfect sense to me.  Now I just have to get better Electrics so I can use photovoltaic panels to power them whilst they traverse the planet in a few different orbits.

This then begs the question:  Do you need satellites then around every celestial body?  One around Kerbin, one around the Mun, one around Duna, etc.?

Edited by Popestar
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24 minutes ago, Popestar said:

Do you need satellites then around every celestial body?  One around Kerbin, one around the Mun, one around Duna, etc.?

"Need" is a very strong word. You can challenge yourself by not using any satellites around anything, and just depending on direct communications when you have line-of-sight to KSC. Or you can challenge yourself by trying to create a satellite network that has continuous coverage of every CB at all times. Or you can challenge yourself by creating a network that's "good enough" for whatever definition you want to come up with.

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If you want 100% coverage throughout the whole Kerbol system and every celestial body, you can build a relay network like this:

https://wiki.kerbalspaceprogram.com/wiki/Tutorial:Setting_up_a_CommNet_system

 

For most(?) of us, I think it's complete overkill. For my career mode, I just took contracts to put satellites in various orbits around Kerbin/Min/Minmus until coverage was pretty good. I play with default settings, so losing connection is mostly just inconvenient - no fine control on the throttle and no placing maneuver nodes until comms are restored. I can live with a 5% chance of that happening given the hassle of setting up an airtight relay network.

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2 hours ago, bewing said:

"Need" is a very strong word. You can challenge yourself by not using any satellites around anything, and just depending on direct communications when you have line-of-sight to KSC. Or you can challenge yourself by trying to create a satellite network that has continuous coverage of every CB at all times. Or you can challenge yourself by creating a network that's "good enough" for whatever definition you want to come up with.

Well, see, now I feel challenged to go out and set up satellites everywhere to make sure I have enough coverage all the time.

Challenge Accepted!

Except I have to figure out what components I need on each satellite first.  Apart from solar panels and batteries, of course.  An antenna, yeah.  But anything else?

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1 hour ago, Popestar said:

Well, see, now I feel challenged to go out and set up satellites everywhere to make sure I have enough coverage all the time.

Challenge Accepted!

Except I have to figure out what components I need on each satellite first.  Apart from solar panels and batteries, of course.  An antenna, yeah.  But anything else?

Just a probe core. And make sure the antenna is a "relay". A relay satellite in orbit actually uses no electricity. And a probe core has a small internal battery. So one solar panel, one relay antenna, and one probe core is enough.

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5 hours ago, Popestar said:

I have to figure out what components I need on each satellite first.  Apart from solar panels and batteries, of course.  An antenna, yeah.  But anything else?

      My consideration (Bolded  are essencial parts for relays, the rest is there for the sake of a more complete answer): 

  • Engines, you need to deploy those satellites somehow. The craft tend to be quite light so priorize  engines that are light first and efficient second (ant, spider, one way RCS thruster, 4way RCS thruster, twitch, vernor,  puff, spark, dawn, terrier). Solid fuel engines are impractical(not throttlable), thus not considered. Dawn's efficient is so much bigger that it can easily surpass everything else in deltaV, the point is: that so much deltaV is hardly needed, other options offer the deltaV needed cheaper and lighter.
  • Fuel tanks, matching the engines off course.Can carry some extra fuel for eventual contracts asking to move that satellite, otherwise just enough to get the craft where it is supposed to be and adjustments/safety margin.
  • Probecore, The OKTO works fine but may swap it for probes with more SAS option later on for convenience (just be carefull to include a reaction wheel for probe which don't include one). For the Stayputinik the lack of SAS (to esser exents, lack of reaction wheels and top node) is a serious annoyance, though still viable option.
  • Solar panelsconsumption is so small that you probably can use the smallest solar panel and get away with it . Placing a few in symmetry and/or using deployable ones helps ensure sun incidence. Gigantors are overkill even on outer planets but by the time you can reach those places you can afford it.
  • Antennas, should be relay antennas and should take in account distance and what we have in the other side of the connection. (e.g. HG-5 are fine for bouncing the signal around a planet/moon but not for an interplanetary link,  even in the first case the other craft need to have at least more than it's internal antenna.) Is not worth to combine weaker antennas if a stronger one is available.
  • Batteries, what your probecore have is probably enough. Even if run dry (e.g. using reaction a lot in the shadow of a planet) solar panel will eventually recharge it and allow the needed corrections but batteries are conveniently cheap and light.
  • fuel cells, complement or/and  alternative to solar panels and batteries but I'm yet to see a case for relay  deployment that it is better than just more panels/batteries
  • rapioisotope Thermoletric generator, great for that application, a bit pricey. The real issue is that it lies in the end of the tech tree, by the time you unlock it is likely to already have more relays than you care about.
  • Science instruments,  those can be dropped after used (contract that requires it completed, science transmitted) and either terminate the dropped stage in the tracking station, let it crash in a celestial body or recover it with a different craft. for use elsewhere. That is more of a conveninence if expecting/planning to do reposition contracts.
  • Positioning, unless a contract asks for a specific orbit just pick it yourself. High elliptial polar orbits work better for long range satellites which main job is to ensure link with KSC while circular equatorial orbit work better for short range relay which main job is to ensure link with the other craft there.
  • Coverage, there is two ways to improve it 1)carefully positioning to maximise conection time of each satellite 2)having more satellite able to connect to/from. 

 

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So, I finally got the Electronics (or is it Electrics?) tech tree upgrade with solar panels, so I'm all set to build my first satellite and put that puppy into orbit.  The only problem I am now facing is how to build it and situate it on a rocket so that it doesn't explode upon launch.  I've tried messing around with couplings and such, but I must be missing a part or a tech tree upgrade or something that will allow me to put the probe inside something else to protect it while it's on its way up there.

Are there any decent tutorials that I haven't seen yet that go into building this?  Is there a way to put this inside something on a rocket that I'm just not seeing?

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4 hours ago, Popestar said:

So, I finally got the Electronics (or is it Electrics?) tech tree upgrade with solar panels, so I'm all set to build my first satellite and put that puppy into orbit.  The only problem I am now facing is how to build it and situate it on a rocket so that it doesn't explode upon launch.  I've tried messing around with couplings and such, but I must be missing a part or a tech tree upgrade or something that will allow me to put the probe inside something else to protect it while it's on its way up there.

Are there any decent tutorials that I haven't seen yet that go into building this?  Is there a way to put this inside something on a rocket that I'm just not seeing?

You are looking for Fairings. Still you should be able to put a very primitive probe in space, if it is exploding because of heat, place some heat resistant part on top, a coupler, the sat, and the rest of the rocket. Not elegant, but it works.

If it is from poor aerodinamics, place more control wings on the bottom of the rocket.

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33 minutes ago, Fierce Wolf said:

You are looking for Fairings. Still you should be able to put a very primitive probe in space, if it is exploding because of heat, place some heat resistant part on top, a coupler, the sat, and the rest of the rocket. Not elegant, but it works.

If it is from poor aerodinamics, place more control wings on the bottom of the rocket.

I worded the question poorly.

i have not yet launched a probe becaus I'm worried about exposed parts such as solar panels and antennae blowing up dye to overheating during launch.  I've seen pictures of rockets here with cargo bays and such housing satellites, and I'm wondering how to build those as I don't see any parts that explicitly do this or any menus that go into this.

Edited by Popestar
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13 minutes ago, Popestar said:

I've seen pictures of rockets here with cargo bays and such housing satellites, and I'm wondering how to build those

Fierce Wolf had it right, the parts you want are called "fairings". They look like a disc at first. You place the disc below the stuff you want to protect. When you have built and placed all the stuff you want to protect on top of the disc, then you right click on the disc and say "build fairing". Unfortunately, there are a lot of hidden rules for how the fairing can be built. But basically, you drag the sides of the fairing upward, and click to finalize sections of the fairing. If you can make the fairing turn the correct color (meaning that you obeyed all the hidden rules), then you can close the top of the fairing to complete it.

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26 minutes ago, Popestar said:

I worded the question poorly.

i have not yet launched a probe becaus I'm worried about exposed parts such as solar panels and antennae blowing up dye to overheating during launch.  I've seen pictures of rockets here with cargo bays and such housing satellites, and I'm wondering how to build those as I don't see any parts that explicitly do this or any menus that go into this.

Don't worry about it, place them at the sides and they should be fine. KSP is a bit forgiving about exposing those at launch. Wait until you hear about Eve

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2 hours ago, Popestar said:

I worded the question poorly.

i have not yet launched a probe becaus I'm worried about exposed parts such as solar panels and antennae blowing up dye to overheating during launch.  I've seen pictures of rockets here with cargo bays and such housing satellites, and I'm wondering how to build those as I don't see any parts that explicitly do this or any menus that go into this.

 

Don't worry, as long your launch profile is fairly standard and  you don't have anything deployed you should be fine. Fairings are available in the Advanced Construction node but or the time being you may try to squeeze the most critical parts inside a Service Bay of keep it behind something more resistant. 

I'd rather prioritize Propulsion Systems node, which gives you the Osca-B fuel talk, the Ant engine and the Spark engine, those are quite usefull for small satellites/probes. The  Miniaturization node provides the first docking port, making offer of station contracts a possibility (those can be fairly easy and lucrative), Fuel System unlocks  crossfeed and fuel transfers and Advanced Flight Controls provides RCS systems. 

As for how to build the "things" there are several good tutorial around that go in more detail, general advice is to design the rocket in inverse order of use(design first what you will use last) with each stage having  just enough to do the task at hand plus a small safety margin. 

 

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