The Retro Solar Rescue

[Laie]

Not sure if I do it right, I'm planning my approach like this:

Not the most time-efficient approach, but then again, I'm only wasting a few hours here. While @linuxgurugamer is trying to shave of days or weeks.

(to clarify: I'm trying to use maneuvers to get a smoother approach to Burberry, gradually closing the gap. The problem with suicide burns is overshooting -- there's plenty of opportunity to save time on a 150-day mission, no need to do it during the mosty tricky part of it.)

And while I'm showing off, here's my silly top-down staging (patents pending). 10sec video, should play inline on chrome and firefox.

 

Edited August 13, 2017 by Laie

[linuxgurugamer]

2 minutes ago, Laie said:

Not sure if I do it right, I'm planning my approach like this:

http://ksp.schnobs.de/burbarry/iteration_v1.jpg

Not the most time-efficient approach, but then again, I'm only wasting a few hours here. While @linuxgurugamer is trying to shave of days or weeks.

And while I'm showing off, here's my silly top-down staging (patents pending). 10sec video, should play inline on chrome and firefox.

 

You need a minimum of about 38000 meters per second delta-v to both go out and come back. That is assuming that you doing it in less than one kerbin year. You can obviously save some off by going directly into atmosphere and having good heat shields to slow you down.

Burberry is moving at about 10,000 meters per second. Kerbin is moving about approximately 9000 m per second in the opposite direction. So that's 19,000 meters per second which you have to do two times which comes to about 38,000 meters per second. You can do it with 37000 but you have to be spot-on with your interceptions Etc. Good luck, I look forward to seeing your results.

[linuxgurugamer]

To clarify, I wasn't criticizing, I was just trying to give some information based on my experience.

[Laie]

*sigh*
It's not to be. On day 91, I have 16300m/s and would need  18200 for a speedy return (not that it would be all that speedy). I don't think I'll sit through another 90 for a boring hohmann transfer.

Interesting tidbit: an encounter on day 79 costs a good 2km/s more, return on day 81 2km/s less.

Either way, I'd need to design another vessel with "just one more stage" -- maybe I will, but certainly not today.

[Cpt Kerbalkrunch]

3 hours ago, Laie said:

Not sure if I do it right, I'm planning my approach like this:

Not the most time-efficient approach, but then again, I'm only wasting a few hours here. While @linuxgurugamer is trying to shave of days or weeks.

(to clarify: I'm trying to use maneuvers to get a smoother approach to Burberry, gradually closing the gap. The problem with suicide burns is overshooting -- there's plenty of opportunity to save time on a 150-day mission, no need to do it during the mosty tricky part of it.)

And while I'm showing off, here's my silly top-down staging (patents pending). 10sec video, should play inline on chrome and firefox.

 

I like your video. I've been top-down staging for awhile now. That's the first time I've seen someone else do it. I normally don't use it until I'm in orbit. It's easier to dump the empties that way. Your system looks pretty good.

Edit: just saw your post with your mission update. Condolences. No shame in coming up short on such a tough mission. Just make your next one bigger. 

Edited August 14, 2017 by Cpt Kerbalkrunch

[Human Person]

6 hours ago, Laie said:

*sigh*

It's not to be.

That's sad, but you can still do it, just not in the fastest way.

Even if you can't beat the Time record, you have beaten the highest launch mass so far. 

I have to wait watching the video until I get home from vacation, but hey: If it works it's not ridiculous.

 

Edited August 14, 2017 by Physics Student

[linuxgurugamer]

I DID IT!!!!!!

Speed run completed!

99 days, 2 hours, 6 minutes.

Pics below.  I just noticed the Imgur album is missing a few images at the beginning, I'll fix that tomorrow.

 I had a mod taking a pic every 2 minutes, I have more than 700 images to go through.

Touched Eve's orbit on the way out.

Ship Information

Rescue 1
Vessel mass:  20144.829t
TWR: 2.05

Rescue 2
Vessel Mass:  5843.95t
TWR:1.29

 

Edited August 15, 2017 by linuxgurugamer

[Human Person]

On 14.8.2017 at 9:55 PM, linuxgurugamer said:

Speed run completed!

Congratulations on beating @Aetharan by quite a bit.

I updated the OP and hope everything is correct. I love all of you for keeping the challenge running.

 

[linuxgurugamer]

On 4/27/2017 at 1:23 PM, Physics Student said:

@linuxgurugamer took his time with a very well planned and executed mission. He burdened himself by using USI Life support, resulting in a very massive ship that required orbital assembly. Total mission time was less than a Kerbin year recordbreakingly low on his 2nd try.

Are You Still Alive?, First orbital assembly, Highest crew capacity** (7), Time record (99d 2h 6m 17s)

Really should update this as follows:

1st mission, total crew capacity 7, long-term crew capacity when taking life support into account:  4 using the Deep Freeze module

2nd mission, crew capacity 3, no deep freeze module

[herbal space program]

So after a hiatus of a  few weeks due to being busy with other stuff, I've been plugging away for the last few days, and it looks now like I'll  bring the whole mission in for under 4,000m/s all told. This album currently has just a couple of new pictures showing where I am now, but I will fill it all in as soon as I'm finished for real.

 

https://imgur.com/a/5URWb

 

Since I last posted, I have continued lowering my orbit until I got to an AP tangent to Burbarry and a PE between Eve and Moho. From that orbit, I boosted for ~470m/s to raise my PE to Eve's orbit and set up a close approach to Burbarry. From that approach, I rescued Burbarry using a Martian-style EVA boost for ~500m/s,  matching orbits right as my rescue ship showed up. It was actually quite a bit easier than I expected to do this. Total EVA time for Burbarry was around 1.25 hours. Once Burbarry was aboard, it took a grinding series of 1 Eve followed by 18 Kerbin assists to get my apoapsis back up to Jool. At Jool I was able to reverse my orbit the first encounter, but with a sun-grazing PE that I could not raise with subsequent Kerbin encounters. So a second Jool encounter was required to raise solar PE to the vicinity of Kerbin's orbit. Due to unfortunate timing, it then took  yet one more go-round, involving an unintentional third Jool encounter, to get to a near-tangent prograde Kerbin encounter.  The gravity assist from that will get me to a 4:1-resonant orbit with PE between Kerbin and Burbarry's Bane, from which I expect to need only another 300m/s max in DSMs at AP to get to a survivable aerocapture. Total dV expended to get to this point has been about 3,665 m/s, so I think the record is probably in the bag (Take heed, @jonny!).Total time expended OTOH looks like just over 200 years. Anyway, watch this space for a full album and a complete mission summary in the next few days.....

Update, 9/11:  I have now made it back to LKO for a total of 4,134m/s,. not quite the 4km/s optimistic estimate I made above. This consisted of 3,579m/s for the rescue ship on the nukes, 505m/s from Burbarry's EVA pack, and somewhere under 50m/s in RCS propellant. I've appended a few more pix to my album (many more to come!) to show where I am now. That would beat the current record by over 1km/s, but for one thing: I still need to land! 

For a regular ship, this would take next to no dV, but putting my plane down on the runway from LKO completely deadstick is going to be pretty challenging. I suppose I could just point it at the middle of the desert continent and land wherever I come down, but that just seems lame after going to so much trouble with every other part of this mission. So a couple of quick questions for @Physics Student just to be sure: 1) Does the challenge actually require bringing Burbarry all the way back to the ground? If so is any location acceptable? and 2) if I fly at all on my Rapiers in atmosphere, will that count against my dV total at an ISP of 3200? I'm assuming the answer to all questions is yes, so it will probably take me just a bit longer to put this thing to bed. If I get bored trying to bullseye the runway deadstick, I'll just land in the middle of nowhere and call it a day I guess, but I'm not quite ready to accept that ending....

 

Edited September 11, 2017 by herbal space program

[Human Person]

On 7.9.2017 at 6:55 PM, herbal space program said:

1) Does the challenge actually require bringing Burbarry all the way back to the ground? If so is any location acceptable? and 2) if I fly at all on my Rapiers in atmosphere, will that count against my dV total at an ISP of 3200? I'm assuming the answer to all questions is yes, so it will probably take me just a bit longer to put this thing to bed. If I get bored trying to bullseye the runway deadstick, I'll just land in the middle of nowhere and call it a day I guess, but I'm not quite ready to accept that ending....

1) Yes, you have to land Burberry anywhere on Kerbin. 

2) No. If you want to make a nice landing and use your jet engines to extend your crossrange, I won't punish you for that. I mean: Your plane can land without using it's engines, can't it? 

 

You could just make a quicksafe, show that you can land somewhere (e.g. The desert), quickload and go for a nice runway landing.

Edited September 12, 2017 by Physics Student

[herbal space program]

8 hours ago, Physics Student said:

1) Yes, you have to land Burberry anywhere on Kerbin. 

2) No. If you want to make a nice landing and use your jet engines to extend your crossrange, I won't punish you for that. I mean: Your plane can land without using it's engines, can't it? 

 

You could just make a quicksafe, show that you can land somewhere (e.g. The desert), quickload and go for a nice runway landing.

Thanks for the clarifications! I did actually manage land it deadstick last night, without difficulty,  on the far side of the mountains from the KSC. I do have pictures of that, but I still want to take another go at the runway without engines tonight just for form's sake. I guess  if I can land it on the runway I'll have the cost record beaten as well, so there's that too! This has been quite a fun and, well, challenging challenge. I hope that some others will give the lowest dV run a try. In spite of my final total, I know I could have shaved off hundreds of m/s more with greater precision and more patience. Adding up all my non-optional DSMs and my initial route to Jool, I think a perfect execution of what I did might add up to as little as 3200m/s. I'd love to see somebody try to prove me right, but it's a pretty big commitment!

Edited September 12, 2017 by herbal space program

[herbal space program]

OK, so I'm finally finished, with all key moments posted Here: 

https://imgur.com/a/5URWb

My final stats are as follows:

dV Expended from LKO-ground: 4149, consisting of 3592 by the rescue ship, 505 by Burbarry on EVA, and 52 in RCS boosts. 

Launch weight: 111.78t, Launch cost: 145,790, Non-recoverable cost: 10,721LF+990Ox+215.8MP = 8,971

Total gravity assists: 47 = 23 getting to Burbarry, 24 getting back, 7 Jool, 23 Kerbin, 14 Eve, 2 Tylo, 1 Mun.

Total mission time: 207Y, 409D

 

The basic strategy was to use Juno-type DSM-Kerbin assist pairs to get to a high Jool-encountering orbit, swing around Jool 4 consecutive times to reverse orbit, then ride a ladder of resonant Kerbin/Eve orbits to a 1:1 Eve-resonant orbit that is essentially Eve's orbit backwards. From this, I boosted my AP to encounter Burbarry, then had him EVA to make up the ~500m/s velocity difference at rendezvous. From there, I immediately encountered Eve again to start climbing an arduous ladder of 18 Kerbin-resonant orbits until AP reached Jool from there. The first Jool encounter reversed my orbit again, and the second one put my PE tangent to Kerbin's orbit. From there, three Kerbin encounters plus a handful of PE-raising DSMs were sufficient to get to a survivable aerocapture from a near-tangent 3:2-resonant orbit. I landed it from LKO for a 13m/s de-orbit burn, a few km short of the KSC. A couple of short bursts from the Rapiers then allowed me to taxi to the runway. What a ride! I have certainly never put more effort into a single mission, but it was fun! On to something much quicker...

Edited September 16, 2017 by herbal space program

[Human Person]

Congratulations, @herbal space program!

You have proven me wrong: Even this challenge can be done with a single stage spaceplane. Great work!

5 hours ago, herbal space program said:

Encountering Eve before getting to that very low PE is probably important to avoid solar incineration.

Lol, but I wonder: how did you plan these gravity assist? One after the other or did you plan multiple slingshots ahead?

Edited September 15, 2017 by Physics Student

[herbal space program]

16 hours ago, Physics Student said:

Congratulations, @herbal space program!

You have proven me wrong: Even this challenge can be done with a single stage spaceplane. Great work!

Lol, but I wonder: how did you plan these gravity assist? One after the other or did you plan multiple slingshots ahead?

Thank you! Halfway through, I was pretty doubtful about breaking the dV record, but as it turns out getting home was quite a bit cheaper than I thought it would be. As to how I planned all those gravity assists, I'd say it was a little bit of both. The basic principle is to construct a table of resonant orbital periods for each body you want multiple assists from, and then plot your encounters so that you eject with a period as close to one of those periods as possible. Generally when you're high up on the ladder, it's easy to hop from one resonant level to the next, but as you get lower down, the waits get longer and longer. Near 1:1, I would set it up so that I had two points of intersection and just run the clock forward until one of then got close to an encounter, then F9 and boost one way or the other to turn that close approach into an actuial encounter. In backwards world, every encounter would raise my AP and lower my PE a little or vice-versa, so once I was on that very eccentric Jool-tangent orbit that encountered Eve, I Was able to get all the way down to a 1:1, not-too-eccentric Eve-resonant orbit and back with nothing but successive gravity assists. In forwards world OTOH, you either raise or lower both AP and PE, and you can only lose energy from a tangent approach, so you have to do DSMs to either raise or lower your PE from AP in order to gain or  lose velocity relative to your slingshot body. I of course had no idea if any of this would work well enough going in, I just kept trying different things. In the end, I'm amazed how easy it was. Like I said upthread, I have no doubt somebody could come along and beat my record by hundreds of m/s, but we'll see if anybody has the patience to take it on...

Edited September 16, 2017 by herbal space program