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NJC2

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Everything posted by NJC2

  1. I'm new at RT, and I finally, after many failed attempts due to brain farts, I have a working relay satellite system in orbit. I'm in career mode with only the communotron 16 and the two short range dishes (50Mm and 90Mm) unlocked right now. I put three satellites in 700km orbits. They use the Stayputnik core with a communorton 16 and the 90Mm dish, plenty of battery power for night and solar panels to recharge in the day. At 700km, they are just high enough for the dishes to maintain LOS and the communotron 16's are in range of one another and at least one is in contact with the KSC. The dishes are targeted at the active vessel. I'm also using Deadly Reentry, FAR and Procedural Fairings. Last night I tried to send an unmanned probe around the Mun, but it lost communication beyond 3km, the range of the built in probe core antenna. I had a Communotron 16 on the craft inside the fairing set to start active. It turns out the Communotron antenna was snapping off shortly after launch even though it should be shielded by the fairing. I don't know if it's a bug with RT2 or the other mods, but shouldn't the fairing be shielding the antenna? There also wasn't any indication that it broke off. The flight status (F3) showed no events. I only realized that it was breaking off when I noticed I was losing control at exactly 3km. I had to put on the short range 500km antenna on and deactivate the communotron during launch. Now to my main problem, which I can't think of a workaround for. The probe did a slingshot around the Mun, grabbed science and came back on a free return trajectory. I had two of each science equipment on board, one to save and collect if reentry was successful and one to transmit before reentry just so the mission wouldn't be a total failure if the craft burned up during reentry. I was afraid the communotron would snap off during reentry, so I used the tweakable system so the parachutes opened at a lower altitude just in case DR killed them if they opened up in the upper atmosphere like they do by default. I staged the parachutes before reentry, but didn't lower the landing struts because with FAR I thought it might cause the craft to flip around so the heat shield was facing the wrong way or DR might cause them to burn up being deployed. I just hoped the communotron would hold up through the reentry so I could deploy the landing struts, but it didn't. The craft touched down and fell over, but luckily it didn't break up. For probes returning to Kerbin, I can always try to reenter near the KSC so the short range 500km antenna is in range which will allow me to deploy the landing struts, but what about sending probes to land on planets with atmospheres? Since you have to retract all of the communications equipment for reentry, how to you deploy landing struts after reentry and re-deploy the antennas once it lands? I played with the flight computer, but unless I'm overlooking it, I don't see the ability to send anything other than maneuver commands. It would be nice to be able to send other commands like retract the comm dish, wait 1m and deploy the landing gear, wait 2m activate science equipment, wait 5m and re-deploy comm dish. As it is now, I don't see any way to send a lander probe to a planet with an atmosphere without first setting up a bunch of relay satellites around the planet, and putting them low enough for the short range 500km omni antenna to connect to it since it is the only antenna capable of operating while moving through an atmosphere. Also, regarding the flight computer, it would be nice to be able to queue up commands before transmitting them to the craft rather than sending them one at a time to be stored in the queue.
  2. I just finished some minor cleaning up tonight. I refueled the de-orbiter with just fuel and whatever monopropellant was left from the refueling craft after docking. When I designed the MODO, the first one I sent up had a "manufacturing defect" that I didn't catch until it was in orbit and trying to dock with the module. Somewhere in the VAB while re-arranging the bottom set of RCS thrusters, the symmetry reset to single, so it went into orbit missing 3 RCS thrusters. I fixed the design and launched a second one, but left the old defective one in orbit since it had precious fuel on it. I had already sucked it's main tank dry, but it had almost a full tank of mono-propellant. That's why I only refueled the main tanks and a tiny bit of RCS. I intercepted the defective MODO and docked to retrieve its monopropellant before de-orbiting it (removing the last of the debris from orbit), which proved to be a little tricky since the refueling ports are on the sides of the craft. I managed to pull it off though. Thanks for the kind words. I did watch a video of someone doing an orbital rendezvous and docking before I tried on my own. It only showed one method of intercepting from a lower orbit and to something in a higher circular orbit. It did teach me enough to figure out how to do other intercepts on my own. After doing it a few times I don't find it that hard. I couldn't do it without having a map view showing ascending/descending nodes and intercept points, along with using the maneuver node to play with. While I like to try and do things efficient, sometimes you just have to strike a balance between efficiency and time. I know I don't do the intercept maneuver the most efficient way by accelerating time and waiting for the two objects to orbit several times and get a close encounter before making the final intercept burn. The way I'm doing it is by first matching inclination, then putting my one of my apsides (I'm not that smart, I had to look up the plural of apsis) on the target's orbit, make a burn at the intercept node to raise my Ap up so I swing out and catch it on the next orbit. I play around with the maneuver node a bit to find out about how much I'll need to burn, but I don't use the node to make the burn. Whenever I've relied on the maneuver node, it never comes out right, so I manually start the burn before the intercept node and watch for the target's position at intercept node to move around in real time. I stop the burn when it gets close to the intercept node, and then tweak it a bit with small pulses of RCS to get it as close as possible (I usually get it within 500m or less). It saves time and doesn't require a large burn, at least for things in circular orbits. When intercepting those objects in highly elliptical orbits, I had to wait an orbit or two to get a good intercept without an insanely long burn. Launching things into matching orbits so far gives me more trouble than an orbital rendezvous. My first attempt was a total failure when I had to refuel the MODO in near polar orbit. I checked the heading of the target craft before launch, it was ~165° descending. So when I launched the refueling craft, I made the gravity turn to 165°. When I switched to the map to see my orbit forming, the orbit was drifting off to the east at what looked more like around 140°. As I was making heading corrections trying to save the launch I had to drop a booster stage which collided with my main engine. I realized the orbit being off must have been to do with the rotation of Kerbin, so on the second try I guestimated and turned farther south, which put me closer, but I still had to keep making heading changes as I ascended. I got lucky though and was able to make it directly into a matching orbit only off by 0.5° of inclination. There has to be a way to calculate what heading to launch in to achieve a specific orbital heading. I was going to make another post if I couldn't find an answer by searching (which I haven't done yet). It probably would have been more efficient/economical to launch another craft into the offset, retrograde orbit of the last two pieces of debris, but I designed the MODO to stay in orbit and be re-useable so I wanted to make use of it instead of launching something else. All but two of the things I was de-orbiting were in low equatorial orbits, so I cleared them first. Counting the fuel required to launch another craft into that orbit with what I would have used if I had done the inclination changes right, it may have be close. Considering that after I refueled, I made the last 70° of inclination change, intercepted and de-orbited two pieces of debris, then returned to within 5° of an equatorial orbit on one Rockomax-32 tank. Doing it the sloppy way I did, it required re-fueling two times, but if I had done it right to begin with, I think I could have performed the full inclination change, de-orbited both debris and returned to equatorial orbit without re-fueling, or at least one re-fueling which may have been equal to the fuel required to launch a separate craft. I may just test that out of curiosity. I can backup my save and see how large of an inclination change I can make with the fuel on board compared to what it would take to launch another de-orbiter in a retrograde orbit. I didn't need to return it to an equatorial orbit after finishing it's mission. I considered leaving it where it was until I needed it again, but I decided to go ahead and bring it back to an equatorial parking orbit. I can detach the de-orbiting module and re-task the craft for something else. I'll leave the de-orbiting module in orbit in case I need it though. I'm thinking I may use it to go to the Mun, since all I would have to do is design the lander and send it up to attach to the already fueled giant rocket in orbit.
  3. I decided to give my synchronous orbit idea a try, and it worked out quite well. Rather than actually put the craft into a synchronous orbit, I just pushed my Ap up to the synchronous orbit altitude (~2,870km since I didn't need to be exact), then made my inclination change burn. I was able to make the last ~70° of inclination change to match orbit with the debris, drop down to intercept and de-orbit the first piece. I then re-establish orbit, intercepted the second debris and de-orbited it. I had about 1/4 of the Rockomax x32 tank left, and was curious if I could get it back to equatorial orbit with that. I pushed my Ap back up to to synchronous altitude (except I overshot and ended up just above 3,000km). I had plenty of time to play around with the maneuver node, and I managed to use the node and plot the 155° inclination change, keeping roughly the same Ap and Pe all in one burn, and it was less than a 1000m/s burn! I didn't quite have enough fuel to pull it off, but I was able to use the RCS to at least maintain orbit. When it was all over with I was only 5° off from an equatorial orbit. My Pe was at 80km and Ap was still around 3000km. At Pe, I burned more RCS to lower my Ap down to around 2500km, then decided to try aero braking. I've never done aero braking before and I didn't know the best altitude to use, so I went for 50km. I wish I'd thought about it before and planned the maneuver node to set it up from the start. The aero braking was working, but I was only losing 25km per orbit and that was going to take too long to circularize my orbit that way, so put my Pe up to 75km then burned up the rest of my RCS and was able to lower my Ap down to 1200km. I'll send up fuel tomorrow, fix the orbit and then park it for whenever I need it later. I'm pretty sure that wasn't the most efficient way to do it because I don't think it even takes a 1000m/s burn to reach the Mun. I quick saved before I did it because I didn't believe what the maneuver node was telling me, and didn't think it was going to work. Once I saw that it actually worked, I figured what the hell and went with it.
  4. I haven't had the time to get back to KSP since my last post, but today I'm hoping to finish my junk cleaning mission. I just refuled the deorbiter and the refueler has about 2/3 of its Rockomax x16 tank left, so I'm going to take advantage of it to push the deorbiter. Now I'm ready to finish the orbital inclination change. I pulled up this thread to re-read before starting the maneuver. Is it really necessary to go as far out as the Mun or Minmus for an efficient inclination change? I was thinking I could put the ship into a synchronous orbit, turn it in the direction it needs to go, then burn to establish the orbital intercept. I know this would require burning up to a synchronous orbital altitude, another burn to slow down, then another burn to get the intercept orbit, but would it use more fuel than a large burn to go out as far as the Mun or Minmus and back?
  5. Funny, I've been doing a little orbital debris cleaning myself. I came here to see if I could get an answer to a different question and this was the first post on the page. After my first few attempts to get things in orbit, I had left a good bit of debris behind. I now to try to make my launch stages self cleaning, but I still had several pieces of debris in orbit. Deleting them from the command center felt like cheating, so I decided to try and come up with a way to knock them out of orbit. After I did it a few times consistently, I figured I would just delete them from the command center and pretend I sent up a ship to do it. However, each attempt was a different challenge and I kept thinking I could do better, so I just kept going. My first design (sorry, I don't have screen shots of it in flight) was to use LT-1 lander legs as a grabber. This was in 0.21 and I didn't know that those legs were bugged when in the lowered position. After matching orbit with a non functioning satellite, I had to leave. When I returned and loaded the game, the legs were gone from my craft. I already put the time to get in orbit and lined up, so I just decided to try and nudge it out of orbit. It worked, but I think I just got lucky too. After matching orbits and lining up, I only had enough fuel for a half second burn. When I nudged up against it I just happened to be facing the retrograde and that half second burn was enough to deorbit the satellite and the deorbiter. My second design I just swapped out the lander legs with an upside down small to large adapter. I figured since nudging worked in the last try that I would just give myself a larger surface area to nudge with. This design didn't work as well though. I went up after a rocket stage left after putting up a satellite. It took me a bit longer to get lined up with it facing retrograde, and when I performed the de-orbit burn the junk rolled off. I had to recapture it a couple of times to slow it down enough to deorbit it. Even then it only dipped into the atmosphere enough to slow it down and took two more orbits before aero breaking it slowed enough to bring it down. My third design I used girders as a basket and the LT-2 landing lets as a lid for the basket. This craft worked pretty well. I was able to capture that rocket stage and had enough fuel, battery and RCS left over that I was able to capture another piece of junk with it. The second thing I deorbited with it was another satellite. It was working, but it really didn't server any purpose. I did discover a small flaw in the design though. That small satellite would slip out between the girders. After that third craft was able to deorbit two pieces of debris, I came up with the idea to design a craft that would stay in orbit and could be reused over and over. I came up with what I call the Modular Orbital De-Orbiter (MODO). It is basically a larger version of my third design, but I have a large clamp-o-tron on the end so I can change out the business end. For the first tool, I just made the same basket and legs design, but used struts to fill the gaps. It worked fine on the first try plucking out another rocket stage, and the second try on another satellite. But when I went for another small satellite it would still slip out because the struts don't physically collide with other objects. I only have two pieces of debris left, which are the first satellite I ever put up, and the rocket stage used to put it there. There was plenty of fuel left in the rocket to deorbit itself, but I didn't know I needed power and a control module on it, so it's just been stuck there. I'm going to bring down both the satellite and the rocket, but the problem is that it is in a retrograde orbit offset about 30°. I designed a new basket and sent it up, attached it, but I go distracted for a few weeks and never finished my junk cleaning. The last thing I did before the break was to refuel it and begin it's transfer orbit. I made it from an equatorial orbit to a nearly polar orbit before running out of fuel. That's where I left off. I just now re-fueled it and I'm about to finish cleaning my junk. Here's a closer look at the new junk catcher design. The refueler is still attached because it has quite a bit of fuel left. I still have about 45° of inclination change to make, so I'm going to use the refueler as a booster until it runs out of fuel. There's plenty of RCS fuel on the refueler that it can deorbit with RCS.
  6. Thanks for the ideas everyone. I didn't think about extending my Ap and making the maneuver farther out. I knew what I was doing couldn't have been very efficient since the burn to change the plane also increased the orbit and I was wasting fuel to prevent my orbit from growing larger at the same time. I did actually think about slingshotting out around the Mun and coming back, but that seemed extreme to me at the time.
  7. EDIT: I posted a followup question here. Original post: Long Story (skip to TL;DR if you want the what and not the why): I'm still fairly new at this. So far I've just done low Kerbin orbit stuff. I wanted to see if I could figure out how to get into orbit by myself without reading any tutorials. Having only done the in-game tutorial, I set a goal for myself to get a satellite in orbit. I somehow managed to do it on my first try, but it ended up in a wild elliptical retrograde orbit and offset 25° (it's on a heading of 245°). Also once I put the satellite in orbit I was unable to get the rocket stage out of orbit. At the time I didn't realize I needed both battery power and a command pod/module to control the rocket stage after detaching the satellite. It took me three more attempts before I successfully put a satellite in orbit and de-orbited the rocket stage(s). After that first attempt I decided to read some guides on the wiki. As it turns out, the ship I built happened to stage exactly with the basic tutorial on getting to orbit. The first stage burned out right at 10km where I pitched over to 45° until I was at 70km, then burned prograde until I had an orbit. That first attempt was sloppy, and I just got lucky. After reading the tutorial, I did the rest of my launches making my gravity turn to the east. As I said previously, it took me another three attempts to get a satellite in orbit and not leave the rocket stage up there too. By then I had accumulated three junk rocket stages and one non functional satellite (I forgot to deploy the solar panels before its battery ran out). I decided to build a craft to see if I could clean up my orbital junk rather than delete it from the Tracking Station because that felt like cheating. Initially I was going to see if I could do it consistently, then I would just delete it from the Tracking Station and pretend I sent up a "deorbiter" to do it. It turned out to be quite a challenge and each one was different, and since it wasn't that much junk I decided to go ahead and manually do them all. The first three craft were single use designs. For my first design, I decided to go after the non functional satellite. I put LT-1 lander legs on the tip of the craft thinking I would use the gear to snag the junk, and perform a deorbit burn. However there was a bug in them at the time. I had to quit before completing the mission, so I saved the game and quit. When I came back and continued, the landing legs broke off after loading it up. I was so close to intercepting the satellite, so I decided to continue and see if I could just bump into it and nudge it out of orbit. It worked, so my second design I just swapped out the lander legs with an upside down small to large adapter thinking the larger surface would make it easier to bump things. I think I just got lucky with that first one, because the second one was harder. I went for a junk rocket stage, and I had a tough time with it. The junk kept rolling off when I fired the engines, and I had to re-capture it three times before I slowed it down enough for it to deorbit. For the 3rd try I went back to using lander legs. This time I designed a kind of basket, and used the LT-2 lander legs as a lid. I went after another junk rocket, and it worked out great. After deorbiting the junk rocket, there was plenty of fuel, RCS and battery left to go after another piece. I decided to go ahead and deorbit one of the satellites since they aren't really doing anything useful. It was when going after the satellite that I realized there was a flaw in the design. The smaller satellite could slip out between the beams. I had to re-capture it a few times, but I was able to get it out of orbit. After getting two pieces of junk with that last design, I decided to build a permanent orbiting craft that I could just re-fuel and keep re-using. I decided to make it modular by putting a large clamp-o-tron on the end, so I could make different attachments and swap them out. I basically just made a larger version of the last design, but put a docking port for refueling and solar panels to recharge the battery. It had the same flaw as the previous design that would let small objects slip out since the struts don't collide with objects, they slip right through. I still used it to de-orbit all but two pieces of junk, the first satellite I launched and its rocket that are in the bad orbit. I made a new module, sent it up and attached it, then refueled, and now I need to match orbit with those last two pieces of junk. TL;DR: To get the last two pieces of space junk I need to make a large orbital plane change of ~155°. I tried playing with maneuver nodes to see what would work the best, but I couldn't find a way to do it with them since I figured I would need to make several maneuvers instead of one big one. At first I thought I should be able to do it by burning 90° between the ascending and descending nodes, but I couldn't get that to work with a maneuver node. So instead I made smallish adjustments (about 1-2min burns) at each intercept node. I've gone from a 90°E orbit to almost a polar orbit of about 170°, and now I'm out of fuel. I'm going to send up a refueling ship and continue. At this rate I should get it matched to the orbital plane of the junk, but it will need another refueling once I get there before I can capture and deorbit the junk. There must be an easier, more efficient way than what I'm doing. As much fuel as it's going to take to get there doing it the way I am, it would have been more efficient to just launch another ship directly into that orbit. I had a few ideas of what to do with it once I finished cleaning the junk. One was to just leave it where it is until I need it to clean up more junk. Also, since it's modular and with lots of fuel, I could always use it as a rescue vehicle in case I strand some Kerbals somewhere. All I would have to do is send up a crew module or lander module to attach to it depending on where they are stranded. Another idea I had was use it as the start of a space station. For either of the last two options I first need to return it to an equatorial orbit. But first I have to finish the job it was intended for.
  8. I've only had it a couple of months, so I'm still new at this. Pretty much the last thing I do successfully is my proudest moment, and tonight was no exception. When I first got it a couple of months ago, I dove right in without reading any tutorials or guides, but I did do the built in tutorial when I played the demo. I slapped together a rocket and actually managed to get it into orbit after several tries. I then stuck a stayputnik satellite on it and I got the satellite in orbit on my first try, but it was a wild elliptical orbit, ~425k Ap ~95k Pe and offset about 30° and going counter to the rotation of Kerbin. I couldn't deorbit the rocket because I didn't put a control module on it, so I could control it after decoupling the satellite. I was determined to get a satellite into orbit and return the rocket leaving no junk in orbit. I read some guides on the Wiki on getting into orbit, and it turns out that was pretty much how I was already doing it. By some coincidence, the rocket I built staged perfectly with the guide to getting into orbit. I used three solid rocket boosters which burned out just above 10,000m, then I ditched the SRBs and lit the second stage liquid rocket and pitched over 45°. I didn't put an SAS or reaction wheels to help stabilize the rocket so whenever I pitched over 45° it was just whatever direction I could hold it, which led to the wild orbit. I made modifications to my rocket, I added reaction wheels and a 3rd stage and this time put a control module on the rocket stage and tried again. I got a good circular orbit going 90° East at ~75k, detached the satellite, but still couldn't deorbit the rocket. I quickly realized my mistake, I had stuck the battery on the satellite, so even though I had a control module on the rocket stage, there was no power to control it. On my 3rd try I changed some more things around. I put solar panels on the satellite and moved the battery down to the 3rd stage rocket. I got the satellite up in a good orbit, and after detaching it I still had control of the rocket. I was too excited controlling the rocket and watching it deorbit and parachute back to the surface that I forgot to extend the solar panels on the satellite. So while I was successful in getting the satellite up and deorbiting the rocket, I still called it a failure because the satellite wasn't functional. I did a 4th launch with exactly the same setup as the 3rd, but this time I extended the solar panels before detaching from the rocket. So now I had 3 satellites and 3 pieces of junk in orbit, and I wasn't happy about the junk. I wanted to do something about it, and not cheat by deleting it from the control center. I was still getting the hang of going to orbit, so I turned my next objective into getting a Kerbal in space. I used the same rocket design, but replaced the satellite with a manned module. I did two successful unmanned test runs by attaching a control module to it and not putting a Kerbal on board before I went for the real thing. My niece was interested in watching me and wanted to see me do the manned orbit, but she had to leave. Two weeks past before she came back over, and I didn't mess with it between that time. She remembered and still wanted to see the Kerbal go into orbit, so I loaded it up and went for it. I was rusty and used too much fuel. I think I could have achieved orbit, but I didn't want to take a chance and not have enough fuel to bring the Kerbal home, so I let it come back down. I tried a 2nd time and let him orbit a couple of times before bringing him back. It's been several more weeks since I played, and that space junk has been nagging me. I finally decided to do something about it, and tonight I finally managed to successfully knock the first piece out of orbit. I learned how to match an orbit and intercept another object in space. I then came up with a design. I put some landing struts on the tip of the ship, and the plan was to lower them (which will open them), get close to the junk and raise (close) them. I was hoping this would snag the junk and I would then be able to deorbit the rocket and parachute both back safely to Kerbin. I decided to go for the defunct satellite first because I figured it would be easier to capture than a rocket and fuel tank. The tutorials I found for matching orbits all showed getting a lower orbit and using your faster speed to catch up to your target. The satellite I was going after was orbiting at 72-75K, so going lower wasn't going to cut it. I figured I could just go for a higher orbit and wait for the satellite to catch up to me and descend on to it. That's what I did, but it still took me three tries before succeeding. The first time I simply didn't have enough fuel, so I added extra fuel to both liquid rocket stages. The second time was just inefficient use of fuel and several mistakes in matching orbits and intercepting. The third time I almost aborted again due to low fuel. I made a couple of mistakes and had to burn extra fuel to correct for it, but I thought I'd still be able to do it. I was 5 minutes from making my last burn to intercept the satellite when I had to quit and go run some errands. I came back a few hours later and when I loaded the game, the landing struts had disappeared from my rocket. I was using the auto save instead of the quick save, but I don't know if that would have made a difference. I decided to keep going since I was so close, but I would have to push it instead of trying to grab it. Now that I think about it, those landing struts probably would have broken anyway when it grabbed the satellite, and then I would have had extra junk to clean up. I made the final burn to match the satellite's orbit. When I cut the fuel, I was 1200m away from the satellite, and with so little fuel left that at first I wasn't sure if I cut the fuel or ran out. The fuel meter looked empty, but the numbers showed I had a little over a tenth units of fuel. I used the RCS to maneuver up to the satellite and swing around so that my engines would be pushing toward the satellites retrograde. I slowly inched forward until I was touching the satellite, then I hit the throttle, and the engines only fired for half a second and I thought it was a failed mission. Then I switched to the map view and saw both the satellite and the rocket's Pe were going to be just under 69k, which should be enough for them slow down in the atmosphere. It was a tense last few minutes for me because I couldn't remember if it was 68k or 69k when the atmosphere actually began. I knew I could at least use the rocket's RCS deorbit it so there wouldn't be more junk in orbit. Luckily they hit 68k and began slowing down. The satellite splashed down in the middle of the ocean almost as if I planned it, and the rocket's parachutes opened and it safely landed a few km away. I wanted to jump up and high five a bunch of people like you see them do in footage of NASA control rooms, but there was no one around to share my triumph.
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