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Spacecraft/Satellites constitute the pay-load of a launch vehicle. Deployment/injection into orbit is a task that probably needs to be performed jointly by the pay-load, and the launch vehicle. Off the top of my heads, say, stuff like any preliminary systems check/activation that may need to be performed outside atmosphere before the pay-load is separated from the launch vehicle.

  • Is there any sort of marriage between pay-load systems (electronic and otherwise) & the systems aboard the launch vehicle?
  • Can all satellites/spacecraft be used interchangeably with all launch vehicles?
Everyone
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    You mean Payload Adapters and Separation Systems? Yes, some are married (dedicated PASS), some are just coupled (standard PASS) during the payload integration process. Pardon the innuendos. Also, how many heads do you have? – TildalWave Nov 15 '14 at 16:40
  • That's it. I didn't even know the relevant terms ... – Everyone Nov 15 '14 at 16:56

2 Answers2

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The short answer is No, not all the spacecrafts (S/C) can be launched with any Launcher. Once this have been told let me be more accurate in the answer:

Selecting the Launcher:

Lets assume the overall dimensions and weight of the S/C are known and the final orbit is, more or less, defined. In such case not any Launch Vehicle (LV) can fit the S/C inside (fairings are already designed) or it is too big to accommodate it inside as primary payload. In the last case a shared launch could be a good solution. The weight and the final orbit are also crucial in order to decide either a LV is capable or not to meet the needs. The closer the injection orbit is to the final orbit, less fuel will be needed onboard the S/C (or longer lifetime the S/C can have). So no any LV has capability to inject the S/C weight where required.

With the previous parameters and, of course, taking into account the cost of the launcher, a list of candidate LV is selected.

Re-designing the S/C: Now the S/C design has to be accommodated for the specific Launcher so here two additional aspects are important:

  • The mechanical loads the LV will induce in the S/C. Can the S/C withstand those loads?
  • The interface between the LV and the S/C (launcher adaptor).

For the first point, if you select one launcher and perform the whole S/C acceptance campaign based in such LV and finally it is launched with another launcher, it could happen some additional test might be performed to ensure the S/C can withstand with the more severe loads imposed by the new launcher. If the loads between selected launchers does not differ too much, the S/C can be tested to an envelope so this problem is avoided.

For the LV adapter... lets say the most critical part is the separation device. Basically there are two main separator device systems: the bolted one and the clamp band. Some LV can install both, but this is not usual. It could happen the selected LV for your S/C has one system and it is different from the other LV capable of injecting the S/C... so if the final launcher is other, there is a problem, in time and cost, since the S/C needs to be modified.

As you see, the design and verification of the S/C is a loop, as it is the design of the LV (it can be tweaked a little). However, the S/C authority and the LV authority are, in general, different entities so there is no (I insist, in general, but not always) electronic marriage between the S/C and the LV. Actually the S/C is usually in "standby" until it is separated from the LV, saving energy. What is the point of having the S/C On if the S/C is not detached from the LV, attitude will not work properly. Usually a connector will inform the S/C to boot once detached.

Francisco
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    I don't suppose you could possibly share a reference/source ... ? – Everyone Nov 18 '14 at 18:13
  • This is an overall correct answer. I'd just like to mention that in commerical missions (I don't know of scientific missions), the operator will usually select two launch vehicles: a primary and a backup. These are determined in time for acoustic, thermal and vacuum testing of the spacecraft. A launcher change can happens even just months before a given launch, proving that the change is usually minimal. – ChrisR Nov 19 '14 at 01:20
  • Sorry Everyone, the answer I gave is based on my studies and professional experience in the Aerospace sector. Some LV have very good and "public" interface documents, where you can find their capabilities and restrictions. Chek the link posted by TidalWave The list of (historical and current) launch vehicle user manuals – Francisco Nov 19 '14 at 12:15
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Every spacecraft is designed to fit one particular launcher, in fact every launcher has its own adapters which have diferent sizes and can carry different weigths. Moreover, the spacecraft has to satisfy constraint on maximun height and diameters which come from the selected launcher.

During testing the loads applied to the structure of the spacecraft are the ones specified in the launcher manual and they are different for each launcher.

You should be able to download the Ariane 5 manual from the Arianespace website, just in case you want to know more about the requitements the spacecraft needs to satisfy.

Rhei
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    I'm sorry but this is wrong. It's actually not that infrequent that some spacecraft would be launched atop an altogether different launch vehicle, sometimes even spacecraft of a same series used different LV's. Usually, nothing about their own design needs to change to accommodate it there, but it might require a custom payload fairing (if used at all) and/or a custom fitted payload adapter to integrate it with the LV. Case in point, the upcoming Orion EFT-1 Flight Test will launch on Delta IV-Heavy, not SLS. And Mars Orbiter Mission also didn't launch on previously designated launch vehicle. – TildalWave Nov 17 '14 at 21:21
  • For the manuals, see The list of (historical and current) launch vehicle user manuals – TildalWave Nov 17 '14 at 21:32
  • Well this depends on the kind of spacecraft, if you for example want to launch a big spacecraft on Ariane 5 and you use the adapter having diameter of 2624 mm than it is not so easy to find another launcher that has another standard adapter of the same size and that means you need to re-design the face that will attach to the adapter or the new launcher might not have the same maximum fairing diameter. Then of course there could be spacecrafts more flexible from this point of view but it is not the rule – Rhei Nov 17 '14 at 21:33
  • Also, there are cases in which it is possible to think about a back-up launcher but this can be done only for spacecrafts that has not particular characteristics in terms of size and weight – Rhei Nov 17 '14 at 21:38
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    OK, but what you're describing is Payload Integration. Each Launch Service Provider has such facilities and they'd work with their customers that they'd often compete for to provide their services to. Rare few payloads are designed from the get go to target only a specific launch vehicle. It would actually be rather foolish if they did, considering how long their design takes. Also, even ballistic missiles can be fitted with different payloads and use standard PASS nowadays. For LV's capacity, refer to e.g. https://en.wikipedia.org/wiki/Comparison_of_orbital_launch_systems – TildalWave Nov 17 '14 at 21:39
  • What I meant is that once you have decided the main characteristics of your spacecraft (size, mass, injection orbit) then you start looking for possible launchers and start the design accordingly (following the launcher manual). At the end of the design and test phases the spacecraft is ready to fit one specific launcher and only in some few cases you can decide to change launcher at the last minute – Rhei Nov 17 '14 at 21:46
  • Again, that's in the majority of cases incorrect. There might be certain obstacles preventing you to select different providers, such as contract obligations, the nature of the payload itself (e.g. classified payloads), budgetary or logistic constraints, but even then the same launch service providers often operate a whole fleet of different launch vehicles of various capabilities. Even same launch vehicles fly in different configurations and Arianespace (since you mentioned Ariane 5) even provides payload fairings of different volumes and configurations (single, dual,...) for most LV's. – TildalWave Nov 17 '14 at 21:54
  • Here's another example. Orbital Sciences is now looking for a stand-in launch provider for a few upcoming Cygnus spacecraft launches to the ISS, since their Antares launch vehicle's mishap during Orb-3 mission and until they replace the Antares' first stage engine. They have contract obligation to NASA to deliver a certain amount by weight of supplies to the station. They'll still use their Cygnus spacecraft, but might actually even fulfill contract obligations with one launch less if they select a more capable launch vehicle than Antares was in its now past configuration. – TildalWave Nov 17 '14 at 22:03
  • About this last comment I actually heard the problem with cygnus is that there might not be the possibility to use another launcher because this means they should do other testings to test the different load-cases...so there is the risk they have to wait until the problem with the original launcher is solved. Anyway...at some point of the process the launcher must be choose otherwise you do not know what inputs you need to use during the tests and at the end the coupled analysis must be carried out – Rhei Nov 17 '14 at 22:31
  • It is true Ariane can provide different configurations for the same launcher (like Ariane 5 ME and Ariane 5 ECA) but if your spacecraft is really heavy or big for sure you will not fit it in the Ariane 4. Ariane 5 ME and ECA are also a special case since they can use the same standard adapters – Rhei Nov 17 '14 at 22:36
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    Another example is most commercial geostationary spacecraft. For example, Orbital's SES-8 could be launched both on a Falcon 9 v1.1 and a Proton. Similarly, Astra 5b could be launched on a Proton and on an Ariane 5. This allows competition between launchers, which helps operators, like SES or IntelSat, to bring down launch prices. Manufacturers, like SSL or OSC, don't have much choice but to adhere to operators desires which are fully expressed in provided technical requirements. Long story short, this answer only applies to a small subset of launches. – ChrisR Nov 18 '14 at 01:36
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    Let me add that operators also want to be able to launch on other vehicles if a given vehicle is not ready in time or has had a mishap like OSC, as mentioned above. In fact, on the SES-8 program, the operator almost ditched SpaceX because they were late in the testing of the upgraded rocket. Operators always choose a primary and a backup launchers. – ChrisR Nov 18 '14 at 01:39
  • That means you have one selected launcher and one back-up solution so you actually have made a choice. And there are also other aspects which restrict the possibile launcher choice, for example if you want to use nuclear power sources you cannot launch with an european launcher, or if the mission if made by ESA than you will have a nice-to-have requirement asking to launch with an european launcher. So at some point you have to make a choice (1st launcher+back-up), you cannot arrive at the end of the design without having a clue on what launcher you want to use – Rhei Nov 18 '14 at 05:55
  • And just think about acoustic testing...how can you know how to perform the test if you do not know how much empty space you have around the s/c because you have notte selected the possibile launchers? – Rhei Nov 18 '14 at 05:58
  • You raise valid concerns, which are always taken into consideration when designing a vehicle. Yes, there is a primary and a backup, and these are decided in at the requirements phase. It's also important to note that a given satellite requires relatively small changes to be adapted to another fairing (supposing a given set of launchers), if any is even needed. Concerning acoustic testing, it is always done in the worse possible scenario. In addition, all testing is always double checked by the operator, who can request further or more thorough testing. – ChrisR Nov 19 '14 at 01:13