Building a Space Station

[Nemoricus]

I'm going to be building a space station using Greg Burch's Space Station Building Blocks with the Big Space Plane and XR5 Vanguard as launchers. That much is settled. However, I do have some questions about it.

1. Orbit: I'd like for this station to serve as a waypoint between Earth, the Moon, or beyond. What inclination and altitude would be good for this purpose?

2. Modules: Now, with the XR5 I can bring almost all of the initial components up into space at one go, but I'm wondering what I should bring up. In particular:

Power: How much energy do you think can be generated by a single solar panel? How much energy would a station need?

Heat Dissipation: How much heat can one radiator discharge and how much heat is a station likely to produce?

Habitable Volume: Given that this station is meant to be a fuel depot and waypoint, how much living space is it likely to need?

3. Propulsion: Is there a good propulsion system that I can use to control the attitude and orbit of the station after it has been constructed?

If anyone has any other considerations, I'd like to hear them.

 

[Kaito]

Power: How much energy do you think can be generated by a single solar panel? How much energy would a station need?

I calculated it out once...at 20o% efficiency, each solar panel of SSBB produces 48000 watts

 

[Nemoricus]

That's good to know. That just leaves the question of how much power the station would need.

I downloaded the XR5 payload configuration files for SSBB and I noticed that they exclude the animated modules. Is there any particular reason for this?

 

[HiPotOk1978]

That's good to know. That just leaves the question of how much power the station would need.

I downloaded the XR5 payload configuration files for SSBB and I noticed that they exclude the animated modules. Is there any particular reason for this?

the Animated SSBB pieces are based on Spacecraft3.dll, which is not capable of spawning pieces with the scn editor. What your need to do is copy and paste the animated pieces into the scn file your using to build the station.

 

[Nemoricus]

Actually, I had thought that no XR5 payload configuration files had been made for them. It turns out that there are. I already knew that they couldn't be spawned.

 

[Zatnikitelman]

the Animated SSBB pieces are based on Spacecraft3.dll, which is not capable of spawning pieces with the scn editor. What your need to do is copy and paste the animated pieces into the scn file your using to build the station.

Spacecraft3 vessels can be spawned. All you have to do is make sure the Spacecraft3 .cfg file is in the vessel folder, or make a .cfg file for the vessel, put it in the vessel folder with the module=spacecraft3 line. You have to be careful to name the vessel the EXACT name of its .ini file.

 

[Nemoricus]

Is that all that needs to be done, or is that it? Just a .cfg file with the exact same name as the .ini file, with the line module=spacecraft3?

 

[Zatnikitelman]

No, the .cfg can be named whatever you want it. This is what the inside of the .cfg should look like:

classname=whateveryouwant
module=Spacecraft3

The vessel name in the scenario has to match the name of the .ini file. And unless you copy and rename the .ini file, you can only have one of the same type of craft in the scenario.

 

[Nemoricus]

So that's why several copies of most animated vessels exist for Space Station Building Blocks.

Well, that useful to know. Now, what about my other questions?

 

[pattersoncr]

I'm going to be building a space station using Greg Burch's Space Station Building Blocks with the Big Space Plane and XR5 Vanguard as launchers. That much is settled. However, I do have some questions about it.

1. Orbit: I'd like for this station to serve as a waypoint between Earth, the Moon, or beyond. What inclination and altitude would be good for this purpose?

2. Modules: Now, with the XR5 I can bring almost all of the initial components up into space at one go, but I'm wondering what I should bring up. In particular:

Power: How much energy do you think can be generated by a single solar panel? How much energy would a station need?

Heat Dissipation: How much heat can one radiator discharge and how much heat is a station likely to produce?

Habitable Volume: Given that this station is meant to be a fuel depot and waypoint, how much living space is it likely to need?

3. Propulsion: Is there a good propulsion system that I can use to control the attitude and orbit of the station after it has been constructed?

If anyone has any other considerations, I'd like to hear them.

I've put a significant amout of thought into #1. See my blog for what I decided on.
You might also try putting the station at the Earth-moon L1 point. I believe you can use IMFD's offset function to get there.

 

[Nemoricus]

I've read both of your blogs and they're very interesting.

The problem with an L1 station is that it's unstable and would need to have its orbit periodically adjusted to remain at L1. Lacking a propulsion module or a good way to use docked vessels for the purpose, it's just not feasible.

The other consideration is that I want this station to serve as a waypoint for interplanetary missions as well as lunar ones.

Is this an impractical requirement? The vessels that I like to use have enough margin to deal with the inefficiencies of an off-plane transfer, but is it significant enough that I should set up two stations for each purpose?

As far as the initial station goes, it needs to, at a minimum, be able to serve as a beacon for later rendezvous, have at least one docking point, and have the facilities to remain functional until the next construction mission arrives.

Time table is another question. How far apart should launches be? I'm thinking that two to four weeks is fairly reasonable.

 

[pattersoncr]

An equatorial orbit or ecliptic one are both useful choices. More than anything else, I think your choice of inclination will be driven by where you want to be able to launch from. I'd make the inclination as low as you can get and still launch from your favorite base.
Regardless of the inclination, dV for a earth-moon transfer will reach a minimum ~twice a month (when the moon is at a node). If you're doing an off-plane xfer, even at other times in the month, your dV shouldn't go up too much as long as the station's inclination is fairly low.
I'm looking for a good way to investigate how the required dV changes over the course of the month. (I know it will reach a min twice per month, but how much higher does required dV get at other times? How long does dV stay close to the minimum? These are the types of questions I'd like to be able to answer.)

 

[Nemoricus]

Given that I like Wideawake, most inclinations are good except for the most equatorial. I'm thinking that ecliptic will work out nicely for most destinations.

So, unless anyone has any further comments on that, I'm going to consider question one closed.

I'm also going to note that the XR5 Vanguard does not maneuver well in the atmosphere, though that may just be the low landing speed.

Part of my building this space station is to get comfortable with reentry and landing on Earth. I'm already capable of landing on airless bodies. Not brilliantly, but I can. Landing in an atmosphere is much harder and trickier.

Is there a good ascent profile for the XR5 Vanguard lurking around? I've looked, but haven't spotted one as of yet. There is the manual, but it's a bit vague.

Once that's figured out, I just need to decide on what needs to go up first and I'll be able to put the initial station into orbit.

EDIT: I just completed a launch and dock with the ISS with an XR5 fully loaded with logistics cargo. At capture two days after launch, I was at 6.0 percent main fuel, 87.7 percent RCS fuel, 12.3 percent scram fuel, and 3433 kilograms of APU fuel left. This was basically on the default settings. The only one that I think that I changed was the LOX mass, to realistic for the amount that should be on the vessel. This was my first ever launch with the XR5.

For a first go, how does this stack up? Also, do I have enough fuel to get back to Earth safely? Safely being defined as not being fried in the atmosphere and landing at survivable velocities, not necessarily at a runway. I plan to jettison all of the logistics cargo before I do so, if that helps.

 

[n72.75]

1. Orbit: I'd like for this station to serve as a waypoint between Earth, the Moon, or beyond. What inclination and altitude would be good for this purpose?

As close to the ecliptic plane as possable(23.4394°).

note that you LAN will drift relative to the eccliptic's LAN at a rate of about 1.4155E-5° per second

but its still the most efficient for offplane manouvers.

 

[wehaveaproblem]

Take a look at the Refuel Spacestation dev threads and also the Toehold dev thread (old station one, not the new base one). In both you will find inclination discussions about the exact orbit you are talking about and the findings made. Basically, if you plan to match the lunar plane (which passes over Ascension btw) then you get decent launch windows every 40 days or something, although acceptable off-plane intercepts can be made more regularly. That's if you have gradient torque and non spherical activated, if not you can launch 24/7. Basically, I'm being a bit vague here cos I'm hung over and feeling lazy, but there is a very attractive orbit to be had, in relation to WIN and the moon. If you DL Resolve International I have a 500km orbit example station in the scenarios there, although it's nothing you can't recreate yourself in a few mins with the scenario editor.

 

[Nemoricus]

The discussion on that is pretty interesting. However, from the comments I've seen here and elsewhere, it looks like an ecliptic orbit is the most useful general purpose one. I think I'll stick the station into a 500x500 kilometer orbit.

Still, I have a pair of XR5 related questions that I'd like answers to. How good was that ascent for a first go and can I get the vessel back to Earth safely?

As far as components for the initial station go, I think a trussed habitation module, the habitation-truss adapter and at least one solar panel will need to go up first. Should I include a communications module, radiator, another solar panel, or a node, or some or all of that list in the first run, space permitting? Weight is not likely to be a problem.

 

[pattersoncr]

After re-reading the referenced threads, will a station placed in an ecliptic stay that way? Won't the plane of the station's orbit precess reletive to the earth's equator and therefore end up with significant relative inclination with the plane of the ecliptic?

Nemoricus,
Your ascent sounds just fine for a first try, especially heavily loaded. It would be more efficient to more fully utilize your scram fuel (ending up with 3-5%). With some practice, you will probably improve this significantly but it is, as I said, a fine start.

 

[Nemoricus]

I ran the scram engines for as long as I could after I turned them on, but the diffuser was redlining and I had to shut them down. It may have been better to have started those engines earlier in the ascent, but when I first turned them on, they were only giving several hundred newtons of force as opposed to the thousands needed to propel the XR5. So I turned them off and waited until I built up more speed before turning them on again. Probably not the best idea.

I still need to bring it down safely. All of that logistics payload probably puts the XR5 overweight, so it needs to be jettisoned before entry interface. I have plenty of delta-v for the deorbit, even with that load. However, jettisoning it after the deorbit burn will change the XR5's flight characteristics, possibly compromising the data given by Aerobrake MFD. And leaving it floating around in orbit is dangerous.

Any ideas?

 

[Zatnikitelman]

Aerobrake's data doesn't really get good until it continuously updates once you're within 200km of the planet's surface. If you want to properly dispose of the payload, burn, then jettison, but do it fast! You can also cheat before the burn by facing your payload bay retrograde and jettison everything at 100m/s.

 

[Nemoricus]

Too late. I already landed the XR5. I ended up performing the deorbit burn and then jettisoning the payload at 100 m/s orbit normal. They landed in a loose cluster in the south Atlantic, a long way from any land.

The reentry was smooth. I didn't even see any ionisation and the dynamic pressure stayed low enough that I could keep the radiators out the whole way down.

I had to use the main engines to reach the base as I ended up about forty or so kilometers short. My landing....was less than stellar. I ended up going across the runway at a slight angle and stopped entirely off it, close to the end of the paved area. However, since nothing broke, no injuries were sustained, nothing was run over, and the XR5 did stop on pavement, I'm willing to call that a successful landing. Or more accurately, my first ever landing from orbit on a body with an atmosphere.

---------- Post added 08-23-2009 at 12:30 PM ---------- Previous post was 08-22-2009 at 02:47 PM ----------

Okay, I've figured out what I'm going to bring.

1 BM230 Trussed Habitation Module.
1 BT201 Truss Anchor
2 BP101 Solar Panel Arrays
2 BR101 Radiators.

However, I need to determine my launch azimuth. I've calculated one, but I'd like someone to check me.

According to my math, to launch into a 23.45 degree orbit from a latitude of 7.970 S, I need to launch at at 23.51 degrees. Does this make sense?

EDIT2: I've checked my route, and have decided that the other launch azimuth at this location would be better. Does 156.49 degrees make sense?