Mod Virgin - Career playing with "Better Than Starting Manned"

[Taleric]

All your designs have that great look of form meeting function

Dave are there any challenges/mechanics you would like to see added in future KSP/BTSM? Maybe a planet with a biome in an incredibly deep canyon, radiation shielding concerns, a planet with an obstructive cloud layer, rover type science, ect?

[Dave Kerbin]

All your designs have that great look of form meeting function

Dave are there any challenges/mechanics you would like to see added in future KSP/BTSM? Maybe a planet with a biome in an incredibly deep canyon, radiation shielding concerns, a planet with an obstructive cloud layer, rover type science, ect?

Radiation shielding could be interesting but I'm not sure how it could be done - most direct implimentations seem like they could be easily gamed. Rover science would be interesting - I'd love to see mechanics that would lead to more then one type of probe instead of a one size fits all packed with all the instruments. I also wish there where some mechanics to encourage/require more then one kerbal for interplanetary trips. Right now the one man cupola is the king of life support which is a bit unrealistic. I've suggested in the past that the cupola have its life support raised to match the Mk1-2 but power requirement lowered. Then add a hitchhiker type capsule with a 'garden'. It would require a minimal number of kerbals to operate but when in operation it would be like a recycler, significantly reducing the life support requirements. This would make it natural to take multiple kerbals on an interplanetary trip to get the advantage of the garden.

[AgentPaper]

Radiation shielding could be interesting but I'm not sure how it could be done - most direct implimentations seem like they could be easily gamed. Rover science would be interesting - I'd love to see mechanics that would lead to more then one type of probe instead of a one size fits all packed with all the instruments. I also wish there where some mechanics to encourage/require more then one kerbal for interplanetary trips. Right now the one man cupola is the king of life support which is a bit unrealistic. I've suggested in the past that the cupola have its life support raised to match the Mk1-2 but power requirement lowered. Then add a hitchhiker type capsule with a 'garden'. It would require a minimal number of kerbals to operate but when in operation it would be like a recycler, significantly reducing the life support requirements. This would make it natural to take multiple kerbals on an interplanetary trip to get the advantage of the garden.

I don't think it really makes sense for radiation to play a really big design role in most missions. It's probably better to just assume that (basic) radiation protection is baked in to the existing parts, and thus their weights.

One way to implement radiation would be to make it only a concern when you get really close to Kerbol, starting somewhere between the orbits of Eve and Moho. This would make Moho a more difficult (and thus potentially more rewarding) destination. Of course, this would still require adding some way of making radiation protection into an interesting game mechanic. If it's just an extra part you have to slap on, that doesn't really do much. If it used a lot of power, that might be more interesting. Perhaps something like a "magnetic field generator" that uses a bunch of power (requiring an extensive solar array even with the increased efficiency) to fend off the radiation.

The amount of power required could increase based on how much radiation you were getting dosed with, and perhaps the part itself could degrade over time, so you have to be careful in how you plan your mission to ensure you have sufficient power, and aren't spending too long in the dangerous radiation. This would also make for a fairly interesting "Sun-Dive" mission profile, where you try to get a probe (or later, perhaps even a kerbal) into low Kerbol orbit, likely requiring late-game power generation and a very aggressive burn to get close enough before your shielding degrades fully.

This could also be used elsewhere, for example by making one of Jool's moons slightly radioactive. It wouldn't be as harsh as getting to Moho, but your power generation options would also be more limited, so it would add some unique complications to the mission profile.

[babale]

I just wanted to say -- thank you very much for posting this. You inspired me to get this mod just as Stock career mode started disappointing me.

[Dave Kerbin]

Ham 6

As I said before I'm skipping around a bit with numbering. Technically this is the second Ham class ship to fly (I'm not sure how much the future trip to Eeloo will use of Ham, I will likely be using the same launch platform and the return capsule but the rest of the structure might be redone). Lemger Kerman will be flying to Duna on a slightly upgraded Ham platform. I've add 2 more supply pods to add a degree of safety (8 pods now, up from 6) and of course there is a Duna specific lander mounted on top since the Gilly lander wouldn't really work.

The same process is used to perform an injection burn to Duna as was used to reach Eve. Once the burn is done the injection tanks and remaining fuel (460L x 2) where discarded like before so the solar array could be opened. Since this trip is to Duna monitoring solar performance is very important. The ship is reoriented several times during the journey to keep the panels from being blocked by each other or the rear engines. 2 small corrections are made mid-flight, one a few days from Kerbin at the AN and another a few days before reaching Duna to bring the approach to about 60 km from Duna's surface.

Arriving at Duna the capture is with engines to setup a roughly 60km x 60km orbit (to allow 50x warping). I didn't get the approach perfectly straight so I'm inclined in my orbit. It's not enough that I'm going to worry about it. The probe Apple 2 can be seen on the surface though it's far from our potential landing zone. Crew reports and biometric readings are taken in low and high orbit and both goo containers on the mothership are used.

The mothership goes for half a rotation around Duna (to get past the night side) while preparation are made for the landing. The lander's supplies are topped up and the batteries checked for charge. The mothership's probe core is activated and SAS+RCS is turned on to keep it stable. This time I remembered and retracted the solar array - the probe core has lots of battery power (it will last several times longer then the life support in the lander) and this avoids potential damage during docking. Finally Lemger takes a short space walk to reach the lander (the desired placement of a Science Jr prevents an internal tunnel) and detaches. After using RCS to move out of the mothership's path the engines are lit up and lightly begin thrusting to deorbit the lander. Once the deorbit burn is complete the heat shield can be inflated (it will block the engines).

The heat shield turns out to be a bit useless. Descent speed never exceeds 800 m/s and by the time the air gets thicker circumstances have reduced it further. One goo container is used in the high atmosphere and crew related readings are taken there and when it reaches the lower atmosphere. At 18km the navball automatically switches to surface speed and I take that as a cue to ditch the heatshield and begin slowing down. I've said before that I consider Duna the most challenging planet to land on - everywhere else you can either use parachutes or just pack enough fuel but on Duna there are multiple chances for your ship to be violently destroyed. The engines are now burning to slow the ship down to an acceptable speed for parachute deployment. Without the heatshield I'm monitoring temperature - the bottom reaches a high temperature of 332 C but no more. At 9km the ship has slowed to just over 400 m/s and the parachutes are partially deployed to start providing me with some free drag. After a few seconds the engines are shutoff since speed is now at 350 m/s and dropping, slow enough I think that I should be safe when they fully deploy.

The parachutes fully deploy at just under 6km, almost instantly snapping the ship from 330 m/s to 105m/s and pushing the G meter for a brief second.

The ship stays in one piece and Lemger seems to pull through fine so the final landing sequence can be executed. With the parachutes open the ship is still falling at 20 m/s - I overshot the canyon I wanted to land on and instead I'm descending toward a 5.5km high mountain where the air is still thin. The lander was only designed for a parachute only landing up to 3.5km so some engine thrust is required to cut the last bit, reducing speed to about 7m/s. My biggest fear about using engine thrust is that it can tip the lander so I'm sure to cut it just before touching down. Even so you can see the lander wants to tip on the steep hill and the SAS kicks in with RCS to keep it planted.

On the ground the second Goo container can be used along with crew and biometric reports. The Science Jr is easily access from the ladder and then surface experiments can be run. The lander still has 354 L of fuel (well above the safety margins I set for getting back into orbit - 320L ideal, 252L absolute minimum). Once everything is done Lemger returns to the lander for a nap while the mothership circles back into position overhead.

With the mothership in position the lander heads back up into space. Because of the inclination a single orbit intercept is not possible. Inclination is adjusted on the first mutual orbit and on the second a burn is made to adjust course and bring the two together. Fortunately there is enough life support in the lander to safely perform these operations (it will dock with close to half it's life support remaining). I did switch between craft so that the mothership could perform some of the burns (specifically the inclination burn) since it had a much easier fuel situation and I want to ensure the lander had fuel to perform the close in burns that required quick attitude control. A consequence of this is that the batteries in the lander didn't drain in relation to the life support (batteries don't drain if the craft isn't focused). This wasn't a planned exploit and the lander had enough battery power regardless to match its life support reserves.

Docking was in the dark and I had actually considered but never got around to installing lights on the mothership for this mission. The lander approached from behind, making a slight adjustment so that it would pass beside the mothership and then casually turns around for a braking burn before using RCS to travel the last 10m for docking. I considered making a GIF but it's dark anyway and it's about 4 seconds between each shot below, so it would have been really long.

After docking Lemger doesn't immediately come back or open the solar array. It seems that with the docking the mothership is now going to dip a few hundred meters into the atmosphere (41,900m) in a few minutes so I'm going to wait that out. After passing safely the sun comes up and Lemger travels back to the mothership's control pod and tranfers all the science. Monopropellent and life support supplies are stripped from the lander. Once the lander has no more use it is ejected using the decoupler that linked it to the Science Jr and through that to the docking port. This leaves behind the Science Jr and Goo containers in the same configuration as the Gilly trip.

The solar array can be deployed again and return burn (1750m/s) to Kerbin can be plotted. There is plenty of life support and fuel for the return journey. The extra engines are dropped after about 1100m/s since their fuel has run out. The center engine carries on to complete the burn.

Returning to Kerbin I setup a burn to lower the PE by about 100km for reentry, but do it in a less then normally efficient manner, lower then the orbit of the Mun resulting in a cost of 1200 m/s. The reason is that I'll also be bleeding off 1200 m/s from my speed by braking into a lower PE like this.

After burning I still have over 800L of fuel left and about 19 minutes before hitting the atmosphere. Speed is currently 3.9km/s but getting faster thanks to gravity. I begin burning all remaining fuel for braking, adjusting my angle to try and keep the PE roughly on target. With 11 minutes to go I've reduced speed to 3.1km/s and the PE is at 30km. I fill up the command pods life support reserve from 2 of the kegs and turn off the recycler. Like before I am going on the assumption that if I wind up in a degrading orbit instead of landing my survival will depend on electrical power rather then life support supplies. Descending over the south pole the rest of the mothership is discarded and the command pod inflates its heat shield for reentry.

Entering the atmosphere at 4200 m/s the pod doesn't bleed off enough speed to keep descending, however the skip is only back up to 35km before it starts falling again. The heatshield gets warm during descent but holds.

After a smooth 2nd descent the heatshield is discarded at 9km and then the parachutes are deployed at 6. The pod softly lands in the ocean.

The mission brings in enough science to unlock the RTG.

[meve12]

Something to consider: Could you put the life support pods underneath the drop tanks(clipping them partially into the main tank, if need be), rather than the solar panels?

[Dave Kerbin]

I don't really like clipping and they'd have to be clipped a lot to fit under the drop tanks since those life support kegs are the size of regular T200 fuel tanks. In the end I just didn't need all the fuel (dropping the tanks was planned form the start so all the other burns where budgeted without that fuel). It's really a case of me building in more safety then I needed, so the ship had more fuel, especially in the injection tanks, then it would ever use. Part of that comes from the fact that I basically built the ship around the launch system rather then building the smallest ship to do the mission and then building a launch system for it.

I'm starting to run some more detailed numbers for Eeloo and it's starting to come together as to how payloads should be split up if I want to build this on the existing launch platform instead of building some super launch platform (with the framerate drop I get I don't think I want to go bigger).

One ship will be the manned ship. The center section will strongly resemble Ham but use a small RTG collection instead of a solar array. The 6 outer modules will likely be short and identical instead of the 2 very tall tanks seen on Ham. There will be roughly 1000 days of life support - 22 kegs attached to the center section and 22 kegs attached to the outer tanks. There will be enough fuel to reach Eeloo orbit where the empty tanks, along half a set of empty kegs, will be discarded leaving 500 days of life support (the return trip is faster then the outbound trip but has a larger margin of error to be accounted for - I'm carrying at least 25% more then required to cover it).

A second ship, piloted by probe core and powered by RTG, will have departed Kerbin ahead of the manned ship. It will travel to Eeloo and enter orbit. Instead of 44 kegs of life support it will be carrying over 5000L of fuel (roughly equal weight) along with fuel pumps mounted to a pair of side docking points. On top will be a lander of similar size (slightly lighter) then the one that went to Duna. The first ship will dock to the side of this supply ship and be refueled. The pilot will then EVA over to the lander which will remain attached to the supply ship as it is undocked from the manned mothership and carried a short distance away before the lander seperates and goes down to Eeloo. Upon return from Eeloo the lander will dock with the mothership so the pilot can transfer over. The lander, except for the science components, will be discarded and the refueled and lightened mothership will return to Kerbin.

[Dave Kerbin]

Still thinking a bit off and on about the Eeloo ship, looking for enough time to realistically tackle it. As a reference the Ham design is 300 tons into orbit around Kerbin (it was designed for 120 tons to reach Duna or Eve orbit) and a second napkin calculation I've done for the weight of a single ship (ignoring some staging) to do the mission by itself was just short of 600 tons which seemed to validate my initial thoughts that a pair of Ham class ships could do it together. The key design issues with the pair of ships are a reliable means of docking and transfering the fuel. If the target ship has any outboard tanks that need refueling then it either needs fuel lines leading to them or each has a seperate docking port. There is then the issue of ensuring I can reliably dock a pair of 100 ton ships one or more times. Even with a lot of RCS thrusters the Ham series wasn't exactly maneuverable and even a tiny amount of spin carries a massive amount of momentum - docking would need to be perfectly straight on because those magnets wouldn't have a prayer against those forces. Using multiple docking ports was one possibility but it raised some serious questions about whether it would mess up the operation of the fuel pump, plus it wouldn't work if the one port that didn't lock on (as often happens) was the one with the pump.

On the idea of a single 600 ton ship I did throw that number into a spreadsheet and came up with a 3 stage lifter (all 3 stages are fully used and discarded in comparison to Ham's 2.5 stage design) that seems like it would be viable under the new .23.5 rules that make joints roughly equal to the strong nuclear force. It might kill the framerate but it could be worth a shot to simply put the entire ship up at once. Granted if budgets existed it would cost more then all previous launches combined - 84 mainsails and over 300,000 tons of liquid fuel, not counting oxidizer.

[Death Engineering]

I think your napkin math is pretty much spot on. My Moho crewed mission is sitting in a 100km parking orbit, which only brings the crew and the lander to Moho, and weighs in at 365t - the return vessel is already out there and is similar mass. The design is such that the command module and returning science undock from the transfer stage and move over to the return stage, eliminating the need for bringing a second cupola. This also means I don't have to try and dock a massive craft to perform a refueling mission.

This was the first large rocket I flew since the strengthening update and was amazed at how stable it was.. dare I say too stable? Nah..

Looking forward to the next update!

[Dave Kerbin]

I think your napkin math is pretty much spot on. My Moho crewed mission is sitting in a 100km parking orbit, which only brings the crew and the lander to Moho, and weighs in at 365t - the return vessel is already out there and is similar mass. The design is such that the command module and returning science undock from the transfer stage and move over to the return stage, eliminating the need for bringing a second cupola. This also means I don't have to try and dock a massive craft to perform a refueling mission.

This was the first large rocket I flew since the strengthening update and was amazed at how stable it was.. dare I say too stable? Nah..

Looking forward to the next update!

Yeah, a Moho mission is very similar to Eeloo. I had written off getting the nuclear engines (another tier 9 tech) because it would require missions to both Dres and Moho, and if I was going to Moho I might as well go to Eeloo. Now that I think about it though I might as well at least run some quick calculations to see what kind of savings I'd get due to the reduced life support cost vs the fuel costs.

[FlowerChild]

Yeah, a Moho mission is very similar to Eeloo. I had written off getting the nuclear engines (another tier 9 tech) because it would require missions to both Dres and Moho, and if I was going to Moho I might as well go to Eeloo. Now that I think about it though I might as well at least run some quick calculations to see what kind of savings I'd get due to the reduced life support cost vs the fuel costs.

You might also want to take a look at some of the changes in the latest releases Dave. I've put some work into smoothing out the transition between techs 8 & 9 that I think will help ease you into your Eeloo mission without it being such a gigantic hurdle to cross.

For example, with the node you purchased, you now have access to a fuel processing unit you can use to setup a refueling station en route. You also have access to asteroid redirect missions which may make it more feasible to purchase a 2nd tech 9 node before tackling the Eeloo trip.

Anyways, you weren't the only one that hit a bit of a wall in your save (happened to me too), so I've been actively working towards resolving that and making the transition smoother.

[Dave Kerbin]

You might also want to take a look at some of the changes in the latest releases Dave. I've put some work into smoothing out the transition between techs 8 & 9 that I think will help ease you into your Eeloo mission without it being such a gigantic hurdle to cross.

For example, with the node you purchased, you now have access to a fuel processing unit you can use to setup a refueling station en route. You also have access to asteroid redirect missions which may make it more feasible to purchase a 2nd tech 9 node before tackling the Eeloo trip.

Anyways, you weren't the only one that hit a bit of a wall in your save (happened to me too), so I've been actively working towards resolving that and making the transition smoother.

I'll look at upgrading, I'm still at 522c. Another thought I've had but haven't worked out (I've been having a lot going on lately so KSP hasn't got a lot of time regardless) is a Duna stop. I had calculated before that Duna was the best location for a fuel stop on the way to Eeloo (Dres is too far out of the way and Jool doesn't help much since it takes almost as much fuel to reach). I'm not sure of the exact setup because I haven't played with the numbers but I'm wondering how much benefit I could get from a probe controlled ship flown out to Duna. A shuttle would then be used to bring a kerbal to Duna. At that range the shuttle could bring enough to refuel the first ship (with Eeloo you burn a ton just bringing the fuel out there) and the kerbal would then abandon the shuttle (and it's 60-100 days of life support) and move into the fully fueled, fully loaded ship for a trip to Eeloo where there could potentially be a third ship with a lander and some more fuel.

Or if I really wanted to I could just go with many ships - deploy a small fleet of simple ships carrying fuel and life support and send them out to Eeloo (they would be small enough that they could dock without lots of pain). Then send the main manned mothership as a followup where it would arrive at Eeloo low on fuel and life support, ready to be refilled.

[FlowerChild]

I'll look at upgrading, I'm still at 522c.

Oh wow. Yeah, a fair amount has changed since then.

Just wanted to point out that if the complexity of going straight to Eeloo is becoming a bit of a kill-joy in terms of your enthusiasm about pursuing it, that there are now other sources of science available that you can probably accomplish in much less time, and which may open up the possibility of making your Eeloo mission less daunting as well.

Capping an A-Class asteroid for example is a pretty straightforward affair that I doubt would take you more than a couple of hours. I know for myself with my first one, not knowing what I was going to really be facing, I just threw together a quick rocket fully expecting to fail but hoping to get a better impression of what was required, and wound up succeeding on my first attempt with plenty of dV to spare, much to my own surprise. Heck, I even managed to set it up in a nigh perfect equatorial low orbit to boot

Anyways, just suggesting it as a fun little thing to do if you're on a tight time budget that may help get you a bit closer to your final goal. Right now you seem to be heading towards trying to accomplish it with what I would consider to be the absolute minimum tech, and I could see that being rather discouraging.

Edited May 1, 2014 by FlowerChild

[Dave Kerbin]

The main thing that was holding back my upgrade was the habitation experiment (Grape 1). It was one of the things in a lot of flux between versions so I didn't want to upgrade and potentially mess it up. I fast forwarded time another 2.4 years to complete the study and I'll post the results of that soon. Once I do the upgrade I'll try out an asteroid mission. I haven't touched asteroids or the grabber in stock and haven't really read about them so it will be a real first time for everything. Without any clue about the fuel requirements I'll just be setting up a modified Ham class ship with something like 60 days of life support and a little asteroid intercept shuttle to taxi between the mothership and the asteroid (the Ham class turns like a pig, one of the reasons for not trying to make 2 of them dock with each other for refueling). The tech tree changes might also alter my big picture once I see them.

[RocketPilot573]

Congratulations on Thread of the Month!

[Dave Kerbin]

Grape 1 (part 2)

So Nedvan Kerman on board Grape 1 is still doing his long term study in Kerbin orbit. Even with all the interplanetary missions it is only half way complete. One odd thing is that it doesn't look like much of any life support has been used up, I'm not sure why that is. There will ultimately be a lot of weirdness around this study and since I'm not running the latest version of BTSM (I will be once the study is done and returned) I'm not going to give much thought to any bugs I encounter.

So I switch to the tracking station and begin advancing 2.4 years. This brings up another bug which I'm not sure is stock or BTSM - it starts getting noticibly slow and jerky advancing the years. This slowness continued right up until I finally exited the game and task manager showed it was likely because of a resource leak. After advancing about 2.4 years I came back and found that the study needed 14.9 hours to complete. So I went to 50x speed, the fastest I could in an 80km orbit and waited a bit. But even if I changed back to 1x speed the time to completion would still say 14.9 hours. So I finally had to switch to another object, advance a day and come back. Upon returning I immediately got the message that the study was complete. 5 years of work has resulted in a whole 300 science.

With the study complete the two supply sections (Grape 2 and 3) are cut lose and the reentry engine is lit up. Once on a reentry course Nedvan moves into the reentry pod which has the biometric experiment attached and decouples from the station. Unfortunately reentry is on the night side of Kerbin so there isn't a lot to see.

Reentry goes smoothly and the heatshield is discarded and parachutes opened for a water landing. Unfortunately a bug seems to have affected the experiment, since despite returning it as instructed I don't get the science. As I said before this is an older version of BTSM and this experiment has undergone changes and fixes since then.

[Dave Kerbin]

Upgrading to 1.55 of BTSM changes the tech tree a bit.

There are two new solid boosters at the beginning, I'm not going to look at the specs now so that it will be a surprise when I start a new career later. A few things are moved to different nodes in tier 5 and 6. There is a node called Negative Results in tier 6 that doesn't seem to do anything...this might be an artifact of me starting on a much earlier version. I guess I'll find out on a second play through. There is also a super heavy solid booster on tier 7, I think that is one of the NASA parts. I probably won't be using it at this stage. A few other parts are shifted around at tier 7, my favorite LV909 is here, I wonder how that will affect things.

On tier 8 I see another NASA part (the silly combined liquid engine and fuel tank) but I also see a rather important change - I no longer have the Science Jr, it has been moved to that flight node I didn't unlock. I'll need to unlock it if I want to use the Science Jr again.

The tier 9 node where I already unlocked the RTG now also has the fuel processor and monopropellent processor. I guess I can use them now if I want. The last major change I see, apart from one fewer tier 9 nodes, is that the habittation study seems to be moved to the lab module. Reading the text it is also only valid in low orbit when there is an atmosphere, so you need to land otherwise. It is still 5 years.

Edit: for some reason there are entries for the Advanced Grabbing Unit in both Composites and Advanced Exploration.

Edited May 2, 2014 by Dave Kerbin

[Dave Kerbin]

Ham 7

This is a first attempt to explore an asteroid. I haven't done this in stock and haven't really payed much attention to how the asteroid missions work - so far the bits of information I know are that you can pick an unknown object to track, at which point it becomes persistant, that they are classified by letter with A being the smallest and E or F being the largest, I know that you can attach to an asteroid with the grabber sort of like a docking port and I know that once attached there is a 'gimble' option of some sorts so you can adjust the angle of the ship relative to the asteroid for the purpose of aligning thrust. I also know that asteroids supposedly act like a ship part you can right click for information and consumables can flow between 2 seperately attached items but I'm not sure how that works with relation to the more restricted fuel flow of BTSM or if the fuel processor works on asteroids.

Without knowing the specifics of the mission I tried to wing it. I took a Ham class ship and removed the now obsolete solar panels, replacing them with 6 RTGs to power the pod. I then attached a small taxi/asteroid lander. It's just a lander can with a supply of monopropellent, batteries and a grabber along with a few science instruments. I've fitted a decoupler to the grabber since I'm not sure if you can release once you've grabbed on so I want to make sure my kerbal can get back to the mothership without resorting to a long EVA. The life support supply has been reduced to 60 days, giving me some time to linger without adding a lot of weight.

I've identified and begun tracking a class A asteroid, OGD-061, which will soon pass through Kerbin's SOI. Ham 7 is launched into orbit to intercept it, hopefully while it is still within Kerbin's SOI to make a return straight forward (there is about a 36 hour window for this). One thing I only thought about after launching is that the RTGs could have been placed on the seperator between the heatshield and the recycler. This way the pod would have power right until the final landing sequence was begun after reentry. With a potential high velocity return from Eeloo I want the pod to be ready for a aerobrake return - it seperates but instead of landing it only slows down enough in the atmosphere to get into a degrading orbit. The pod carries plenty of life support supplies, it just needs power to last long enough for the orbit to degrade enough to bring it home (that strategy was used for some of my early probe return missions, making 3 passes through the atmosphere for a soft return). Given the way this mission turned out I regret not being able to test that system.

The ship is aligned to match the asteroids path and then a basic intercept is plotted. I can't seem to get it below about 70km with the node but I assume that I can refine that. The two question marks in orbit are Grape 2 and 3, which took on those icons after being detached from Grape 1. I have no idea why and might try to change them.

As I get closer I can't seem to get the intercept refined. I finally make the burn to align their orbits and I'm still at least 100 km out. I can't really figure out how to get them close enough without going on a longer deep space journey. Since I haven't planned this out enough and it's obviously not going right I decide to call off the mission and bring Lemger home. A hard burn brings him back into orbit around Kerbin and on and landing course.

I'm a little slow on getting things setup for reentry. The lander is discarded long before hitting the atmosphere but the final pod setup isn't done until I'm already descending. The monopropellent valves need to be opened before seperation and pod consumables double checked along with some parachute tweaks. By the time the pod seperates it is already at 43 km and has to expand the heatshield and rapidly turn around. The pod is aligned in time but I cut it much too close for comfort.

The rest of the reentry proceeds normally. The pod slows down and when it is safe the heatshield is discarded and SAS turned off. Below 6km the parachutes are deployed for a soft water landing.

Much like some of my early missions in BTSM I think I need to treat these asteroids as something new (which they are). I need to approach them step by step so I can figure out how to work with them. I'm going to break this down into several smaller missions with specific goals.

Mission 1

Send a small one way probe to grapple a class A asteroid. Since it's unmanned I won't have an time pressure on the intercept. It will carry some basic science instruments (not sure if these can be used in stock or BTSM) but the real goals of this mission will be to figure out the particulars of intercepting an asteroid, determine if an asteroid passing Kerbin can be intercepted in a reasonable amount of time (is a manned mission practical on a passing asteroid or does it need to be captured first) and finally I hope to find out the rough mass of a class A asteroid, which is important if I need to capture it.

Mission 2

Assuming I need to capture an asteroid for a practical manned mission this will be a mission to travel out and capture one (maybe the same one I've already got a probe on). This will bring a class A asteroid into Kerbin orbit.

Mission 3

A manned mission to the asteroid. This will attempt to determine what science (beyond whatever might be possible in mission 1) can be done on an asteroid and what the return value is, at least for a class A.

Mission 4

An unmanned mission to the same captured asteroid, this time with a fuel processor that will be attached to the asteroid along with a tank and docking/pump setup. This will determine if it is possible to extract fuel from an asteroid.

[FlowerChild]

On tier 8 I see another NASA part (the silly combined liquid engine and fuel tank)

Just a quick point here: it's worth checking the stats and description on that part as I've completely repurposed it from what it is in vanilla. Because yes, it is silly, and I decided to come up with a completely new role for it so that it will hopefully make a bit more sense

Glad to see the above reports man! Made for a good read with my coffee this morning

[Dave Kerbin]

Jam 1

I'm skipping over the letter i because I have several 'Ice' blueprints for an Eeloo mission, though they might not get used now. Jam 1 will attempt to fufill mission 1 of my asteroid goals. Since only basic equipment is required I fit it on the well used 60 ton launcher, most of the payload is fuel and I have about 6000 m/s once I reach orbit. The outer fuel tanks are on a single stage, I haven't used any fancy fuel lines since I think I already have enough delta-v. Since it can stay up indefinitely I simply launch the ship into a 100 km parking orbit and then go back to the observatory to find an asteroid. Something I've neglected to mention is how much debris is in Kerbin orbit beyond the visible stuff like all the discarded landers around the Mun. I've had several close calls where discarded boosters passed less then 8 km from a newly launched ship. Coming up to a 100 km gets me away from most of the debris which is between 70 and 80 km (most lower tech missions made their circulization and injection burns from a low ~74km orbit). I've combined two screenshots made in rapid succession (a few frames apart) to show what ships in standard orbit are dealing with.

I'm looking for a suitable candiate to intercept. It needs to be class A (no point in measuring the mass of a larger asteroid yet, I'm trying to gather information on the smallest kind for a realistic first capture mission) and I want it to be in close orbit to Kerbin. There is an immediate class A candidate but it is about half way to Duna's orbit so I ignore it. Several weeks of watching produce a drought of class A asteroids (though I noted several as large as a class E, class F is either very rare or I was mistaken in the scale going that high) but after 45 days a new class A appears and it is an excellent candiate. Kerbal astronomers label the object YSQ-213 and it is following Kerbin closely, it will cross Kerbin's SOI in about 40 days.

Last time I waited until the object was in Kerbin's SOI to try and intercept it. This time I will break free of Kerbin and go after it before it reachs Kerbin. I plot a minimal escape from Kerbin's SOI - I'm raising my orbit just slightly above Kerbin's. The initial course looks good, even without course correction I'll be coming close to YSQ. I can also see that OGD-061 (Ham 7) is still within my tracking range too though I expect contact will be lost at some point.

I can also see that YSQ-213 is on a very close orbit, even closer then I had originally estimated. The short blueish line at upper left is my probe on its way to leave Kerbin for deep space, while the big sweeping turquoise line (visible now that I've selected the asteroid as my target) is where YSQ is going to swing past Kerbin in 5 weeks. If I can figure everything out in time it shouldn't take more then a nudge to capture it.

My first correction burn actually brings me back into Kerbin's SOI by a few m/s which I correct with a second burn. However this new course will take 14 days before I leave Kerbin again. After an inclination burn to bring me within 4000 km of the target I settle in until I'm near the closest intercept point (about 4000 km) I burn to begin canceling out relative velocity until there is a difference of about 100 km. From there a series of small corrections gets my intercept down to 20 km - at the end of each burn I check to see if altering my speed, direction or angle or bring me closer. It's been 21 days since leaving Kerbin, which means I'll be intercepting the asteroid at about the half way point.

From here I can handle it like a docking approach, canceling out velocity and coming in closer and just adjusting as I go. I get direct visual contact at about 500. YSQ-213 isn't much bigger then the probe.

The claw is deployed and attaching seems to be as easy as flying straight into the asteroid. There doesn't seem to be any pull or strain. Attach it doesn't seem like any of my science instruments are useful -they all seem concerned with me being in high sun orbit rather then the asteroid. Right clicking the asteroid itself shows me it has some quantity of material - could this be for converting to fuel with the processor? I also see an option to claim the asteroid. I don't know what that does so I'm not going to try it until I've done everything else I can with it. Unfortunately I don't have a mass read out, at least not a direct one. Using the ship information on the map screen I can see my ship is now 32.51 tons - without doing a precise calculation of how much the ship weighs without the asteroid that would put YSQ-213 at around 8 tons, much lighter then I expected it to be. Based on the size of my ship, which is mostly fuel (the outer tanks are almost entirely empty), I'd make a ball park estimate that the density of the asteroid is about 1/4 that of rocket fuel. Since kerbal rocket fuel+oxydizer seems to have a density of 5 kg/L that means the asteroid is only about 25% denser then water if my eyeball measurements are correct (though they could be very wrong, I'm really just making a quick visual comparison and guess). That makes the composition of the asteroid something of a mystery - iron is something like 800% denser then water and silicon (dirt) is still 200% denser. Of course asteroids might be composed of other elements too (certainly things like oxygen and hydrogen are more abundent in the universe) and I went over to Wikipedia to see if there was any information. Apparently my guess for the density of the kerbal asteroid is not far off the density scientists have estimated for some (C type) real ones.

I try clicking Target Center of Mass which I think did something - my target indicator moved a tiny bit though I'm still looking at the negative side. The claw has a free pivot option (this seems to let it flex instead of being rigid) though I have some trouble lining things up. I don't think that I quite understand this part yet. I experiment a bit with RCS - it seems I can get the whole thing turning though I'm not sure if navigation works. With lots of fuel and nothing else to do I sit in and wait for YSQ to reach Kerbin.

Arriving at Kerbin navigation proves to be weird - I can set a node for capturing, but the blue target wants to move around wildly, it won't stay in one place. As I reach the PE I burn in a direction I hope is correct. Like I said it should only take a nudge to get into orbit and it seems to do it, though the asteroid is now in a spin. I'm now in orbit around Kerbin at least so I've got my second missions objective done. The safest place to try another burn is at the AP, since I don't risk breaking orbit. Rather then try a node I just burn using the prograde/retrograde markers which seem to be lined up correctly.

I make a few more burns as the probe passes the PE/AP but they need to be short since it can't hold steady and thrust needs to be kept low. Once the PE is at 200 km I focus only on lowering the AP. Eventually I tried working on the pivot again and have some success in figuring out how to get it centered. I don't think I've got it perfect but it's closer enough that I can make more realistic burns without going too far off course. Once the orbit is nearly circular I start working on inclination which means keeping the orbit from going too far off in the process. Eventually I get down to a -21 degree inclination going in roughly the 'correct' direction (east to west). It should be possible for a ship to launch and meet with the asteroid without too much trouble. I've still got some fuel but monopropellent is running short so I'll conserve what I have. The next mission will be a manned visit to see if I can extract some science. After that I'll send up some equipment to start prodding my pet asteroid and see what it can do (things like fuel transfer through the asteroid, if the processor works and if so does it consume 'material' and at what rate).

[FlowerChild]

Just as a forewarning Dave, I know you prefer to avoid spoilers, but in this case it's an entirely out of game thing that may muck up your discovery process for no good in-game reason:

Processing of the asteroid resources is the next thing I'll be working on. So, if you do it now, it won't work. If you wait a release or two, then it will

I included the resource itself earlier than the functionality to process it as I need to initialize all that data when an asteroid is first encountered, and didn't want to muck up people's saves later on when I included it.

[Dave Kerbin]

Kiwi 1

Kiwi is a manned mission piloted by Merdun Kerman to visit the asteroid I now have in orbit around Kerbin. It should be pretty straight forward though I have several objectives to I want to complete:

• See if a Kerbal can perform any science on the asteroid
  
• See if fuel or monopropellent passes through the asteroid
  
• Find out what the Capture command does
  
• Test the RTG equipped reentry system for future deep space missions
  

Since this is only to orbit and then adjust 21 degrees the ship doesn't need to be big. The reentry portion is somewhat fixed, since I want it to be a copy of the design I used on Ham and intend to continue using for deep space missions. For this reason the recycler is still attached, though I've reduced the amount of life support to 200 to bring the launch weight into the correct range for the 30 ton standard lifter I am using (I haven't used one of these in a while). The RTGs are attached to the last seperator, so they will be retained until the heatshield is discarded which is done at about 10-16 km from the surface when landing, followed later by the parachutes opening. In place of the experiments (I no longer have the Science Jr unlocked) I've attached both the grabber and a minimal fuel pump experiment consisting of an isolated tank and a fuel pump. The first stage booster with 6 Skipper engines gets the ship most of the way into space and then the second stage booster, which is just a single tank and Skipper, take over for the orbital insertion with about 100L of fuel left.

An 831 m/s burn is used to adjust orbit to match the asteroid, with 2 orbits needed before they are close enough for a final push for interception that probably burns another 150 m/s in total. The first close interception is just under 1km (look at upper right), but I'm not going to try and link up at that point, on the opposite side of that same orbit they will pass within 200m of each other.

This time when I make contact at about 3.5 m/s it is like a crash, bumping into the asteroid and sending everything into a spin with obvious stress on both attached ships joints. This stress would appear any time I came out of timewarp.

There doesn't seem to be any science I can do from inside the ship so Merdun gets out to explore the asteroid directly. He takes a sample but it doesn't seem to be worth anything. Reboarding the fuel pump test is done but it seems that fuel cannot be pumped through the asteroid into the other ship (the asteroid is not a 'crossfeed' part). I forget to try moving around monopropellent - I have a feeling I could move that and life support around.

Finally I try the capture asteroid command. This starts an experiment like the habitation study, requiring 60 minutes and showing me that it is being done on a Class A asteroid in Low Space. This raises a number of questions I'll need to find the answers for later: could I have done the 'capture' experiment way out in deep space, is there a matching experiment (and result) for high space, and can it be done with a kerbal involved?

After 60 minutes the experiment is complete and I get 500 science! The experiment seems to be 'stored' in the asteroid but I can right click and use the 'transfer' to move it to the command pod. It also looks like it can be transmitted. With the results I detach from the asteroid (testing if the 'release' function on the grabber does what I expect) and then the grabber and fuel pump equipment are discarded before a reentry burn is made and the capsule seperates from the service module.

The capsule performs normally during reentry. I turned off SAS but kept ready to use RCS to see that it was naturally stable. When the heatshield is discarded I found out that the seperator seperates everything - even radially attached items are removed unlike the decoupler which only detaches from whatever is linked to the top node.

[PeterPan]

Grats for Thread of the Month! You deserve it

[Dave Kerbin]

Jam 1 (Extended Mission)

To answer a few lingering questions about the asteroid capture experiment I'm extending Jam 1's mission just a tiny bit. Jam 1 can be seen here still attached to asteroid YSQ-213 with the discarded Kiwi grabber in the foreground and the Death Star in the background.

The first step in this extended mission is to nudge YSQ back into high orbit. We don't need much, just >250 km to change the biome. Since I sort of figured out how to center the mass near the end of Jam 1's main mission I can fire the engines at low thrust and stay on target with only a small amount of input. There is enough fuel for everything I have planned (almost 200L) but RCS is low at 26 units and falling. RCS needs to be conserved so rotating the asteroid is done slowly, just a few puffs to get it moving and then let it rotate freely until it is pointing at my planned maneuver. Two burns bring the orbit up to ~260 km. I try to perform the capture experiment again but I'm told the capture experiment can't be done right now.

That's usually the message I get when an experiment is not in a suitable biome but there is one other possiblity, it could be that a manned pod is needed for the experiment. To determine that I do one more burn to lower my PE into low orbit again and when I pass below 250 km I try the experiment again - this time it starts just fine, proceeding until I come back into high orbit and it cancels.

So now I think I know the parameters of the experiment - it can be performed by any ship under control, it must be performed in low Kerbin orbit and it takes 60 minutes after which I can transmit the result (500Mbit). The only thing I don't know is if it can be repeated on a second class A asteroid. Since this would allow for infinite science without showing any progression I highly doubt FlowerChild would have allowed this. I think my time would be best spent looking at a class B asteroid to see if I get 500 science or if the science scales with size.

[Dave Kerbin]

Jam 2

The goal of this mission is to grab the next type of asteroid, a class B. I've assembled a new ship for this mission, one I hope I can reuse for most or all of the other asteroid capture missions. It's based on the Ham launcher so it's carrying a lot of fuel and power and I've configured the top in such a way that if one of them is not enough to finish the job of pulling an asteroid into low orbit it can detach most of itself and let another take over. I found during the first mission that monopropellent was in short supply so not only is this one of the few ships I've built that uses a large RCS tank, it's also designed so that the body of the ship can be discarded, leaving only the RCS tank and some RCS thrusters attached to the asteroid. This way if two ships are needed to capture an asteroid the first ship can at least continue contributing RCS.

After launching the unmanned asteroid hunter into a parking orbit around Kerbin I went looking for a suitable asteroid. That search revealed some potential targets but also turned up something unexpected - a class C asteroid marked RJM-005 that would visit Kerbin in just over a month. Kerbin's astronomers have spotted a number of class C asteroids but this one was different from the others due to the course it was taking.

With RJM projected to strike somewhere near the south pole action had to be taken. Jam 2's new primary mission is now to divert RJM from its collision course, with a secondary objective of capturing it safely. An outbound 937 m/s burn was calculated that would bring it within 100,000km of RJM in 21 days. I need to catch up quickly so I can't dip in and out of Kerbin's SOI lining up an approach. After the initial burn which used up the first 2 tanks several smaller burns where made over the next 15 hours of flight as it moved away from Kerbin toward deep space. These where designed to refine the approach, bringing it down to under 100 km. Exiting Kerbin's SOI doesn't alter that projection, however timewarping does seem to - 5 days from the asteroid I slow down and find my approach is now 3000 km off. A burn is made to bring it to within 900 km and at that point the probe begins to cancel out all but 25 m/s of the relative velocity.

At this point a hard burn is made to flip around the relative velocity to 90 m/s but heading on a course that now brings it within 9 km in less then 20 minutes. There the velocity is canceled out again and another inward burn is made, to bring the probe along a course to within 100m of RJM.

Approaching RJM I begin canceling out most of the remaining velocity. However I decide on a different approach then trying to line up a course toward it and juggle adding velocity to line up and braking to prevent to hard a collision. Instead I let the ship drift past the asteroid, in the below screenshot the ship is facing backwards, ready to break its remaining 3.6 m/s velocity relative to RJM. Doing it this way allows me to come to a halt just behind the asteroid, less then 100m away. This makes it much easier to make a slow and exact approach, since I am speeding up to catch it rather then trying to slow down while hitting it. This allows for a nice soft capture. I forgot to take mark of the mass before, but a rough estimate based on fuel puts the asteroids mass in the range of 130 tons.

From here I need to line up the engines with the center of mass. By approach the asteroid like this I seem to have the target designators in a better way then before, making it easy to get it straight. I've got enough power to turn the asteroid and the thrust vectoring from 4 engines works well to keep it on course. Altering the asteroid's path so that it passes 200km from the surface is easy at this point.

Arriving at Kerbin the drives are used again to bring RJM into a stable orbit around Kerbin. The fuel in the second set of tank is exhausted, which means 2 fewer engines and slightly less control. Since the asteroid is already in orbit I don't try to lower that orbit yet, I can wait until it passes around and plot an ideal burn. It will take almost 1000 m/s to put the asteroid into low orbit and I've already burned 400 of that. With 3 engines the second burn will take 3 minutes but is still easily possible with the available fuel.

In stable low orbit the asteroid is captured for 1000 science which is beamed back. I can unlock the Science Jr again (completing the one tech 8 node I skipped). While 130 tons is obviously a growth over 8 tons I still think my improved Jam class ship will be enough to capture an E class, I just might need a second or maybe even third to help refine its orbit once captured so the science can be done.