Dzhanibekov's docking challenge

[Alchemist]

Some history:

2 October 1984 - Soyuz T-11 undocked from Salyut-7 station and returned to Earth. The station was left unmanned.

1 February 1985 - due to electric system malfunction all systems of Salyt-7 station were fully shot down

Despite having no attitude control, the station maintained a stable attitude due to drag an gravity gradient torque, what was proven by tracking stations.

6 June 1985 - to attempt recovering the station Soyuz T-13 with commander Vladimir Dzhanibekov and engineer Viktor Savinykh was launched.

Without the navigation systems of the station, the usual rendezvous and docking navigation equipment of the Soyuz was useless. The tracking stations navigated the craft to the station with 10 km precision with approach from the side where supposedly was the passive docking port (because the craft had active docking port).

2 days later the craft approached the station. The only tool they had working without response from the station was the distance measurement laser.

When approaching the station close enough for visual confirmation, the crew saw that they are approaching it from the wrong side - here was the active docking port. The ground control responded that they are free to abort the mission, but Dzhanibekov refused.

He navigated the spacecraft past the station and docket to the port on the other side.

Soon after that the crew opened the airlock and began their mission to repair the station.

Now here's your mission: replicate the most daring docking operation! Dock to an uncontrolled station/vehicle with nothing but the distance measurement!

So the rules are:

* No controlling the station. No automatic control systems either. It's broken.

* No navball target mode - the navigation is not working without response from the station. Just close the navball when approaching the target. Also don't use the map when closer than 2 km to the station.

* No other docking navigation or autopilots!

* The rescue craft must be manned.

* You can use the map to arrange the rendezvous, but don't get it below 500m. Bonus points if not used the targeting on the map or closest arranged approach is above 2km.

Bonus objective - docking port on another side (more than 90 dergees from your original approach direction.

* If the station has multiple docking ports, select the furthest from you initial approach

* You must get direct approach from the wrong side (let's say less approach less that 250 m) before starting the flying around the station.

The leaderboard objective: Soyuz-T still had peroxide RCS with fairly limited amount of monopropellant. Complete the bonus objective with least RCS spent!

* Only monopropellant RCS. Don't use small liquid-fueled engines oriented differently than your main engine instead of liner RCS.

* Also don't use RCS with higher than stock ISP.

* Your score is RCS spent (screenshot with resource tab just before docking) per mass of your spacecraft (screenshot from map mode with craft info open when you achieve orbit) - lowest score wins!

Additional bonus (separate leaderboard): do this with no torque-producing parts! (disable the gyroscopes of your capsule - Soyuz uses RCS for attitude control) How much RCS will it take now?

Proof that it is possible: many people experimented with docking since 0.14. When there was no rendezvous and docking navigation...

Leaderboards:

Freeplay (no scoring):

Docking expert - normal docking:

...

Docking master - safely navigate around the station:

...

Scored:

Docking grandmaster - minimal RCS spent per mass of the spacecraft

1. Kasuha - 0 RCS fuel spent! 16,3 t ship.

Dzhanibekov's level - no gyroscopes!!!

1. Aphobius - 5.72 (103 RCS / 18 t) + rendezvous without map and navball!

Edited March 27, 2014 by Alchemist

[Naten]

Wow, this looks fun! Will try.

[Kasuha]

Sounds interesting but too vague for me. I sure am not supposed to get my craft to orbit with nothing but RCS so the question is at which point am I supposed to drop conventional engines and use RCS?

Also monopropellant usage depends a lot on mass of the craft, is there any limit on how heavy/light the craft should be? Are command seats ok? Do we even have to bring any Kerbals?

Maybe the best would be if you prepared that as downloadable scenario so everybody's starting conditions are the same. Because without that, the "minimal RCS spent" category does not have much sense.

[Aphobius]

Kasuha is right, this is mostly about who can make the smallest ship. I'm not very interested in that.

Just a video to show off, made it a little harder than it was required, tell Scott Manley I give free lessons.

EDIT: Just uploaded it, wait a second if you want better quality, it's full hd.

Edited March 26, 2014 by Aphobius

[Alchemist]

Sounds interesting but too vague for me. I sure am not supposed to get my craft to orbit with nothing but RCS so the question is at which point am I supposed to drop conventional engines and use RCS?

You're not supposed to go on RCS alone, you can and should have main engine. I just meant you should'nt have some kind of bipropellant RCS, like putting differentily orienter small engines with action groups (because then RCS amount spent won't mean anything). I should have written it more clear.

Also monopropellant usage depends a lot on mass of the craft, is there any limit on how heavy/light the craft should be?

I know, that's why the scoring is: "Your score is RCS spent per mass of your spacecraft".

However I suppose someone will pull out a no-RCS docking with extensive craft rotation, that's why there is the next level with no gyroscopes.

[Aphobius]

Last video I missclicked M instead of N and that turned the navball on, but I didn't had the station set as target, so I don't think it matters. But made another video just in case.

I had some problems during the launch, the rocket rolled 90 degrees without me noticing. Anyway, I guess it's better this way. so you can see that I don't learn the buttons like a monkey and follow my "internal rhythm" to press them in order, like some popular disc jockeys around.

[Kasuha]

You're not supposed to go on RCS alone, you can and should have main engine. I just meant you should'nt have some kind of bipropellant RCS, like putting differentily orienter small engines with action groups (because then RCS amount spent won't mean anything). I should have written it more clear.

When docking with my orbital station I am usually able to bring my ship within 60 m from it (and match speeds) using the main engine. And no, I don't need any directional engines mounted, I'm not even wildly turning my ship around in space, it's all just about controlled braking. So really, this needs more detailed specification of what the starting conditions are supposed to be.

[Aphobius]

When docking with my orbital station I am usually able to bring my ship within 60 m from it (and match speeds) using the main engine. And no, I don't need any directional engines mounted, I'm not even wildly turning my ship around in space, it's all just about controlled braking. So really, this needs more detailed specification of what the starting conditions are supposed to be.

What's not clear? Bringing your ship within 60m using only the main engine is going to be slightly harder without navball (I do kinda bad in the video, but with a little training, I'm sure I could do almost as good as having the navball).

The only thing to improve this challenge would be to add a save file so everyone use the same ship, else, building the lightest crap you can is not very fun. But the rules are clear enough.

[Kasuha]

I'm pretty sure Dzhanibekov did not use his main engine anywhere near the station. So I am sensing certain divergence between the "replicate the most daring docking operation" idea and actual rules. If we should replicate that, we should be put on trajectory which gets us somewhere near the station and take on it using RCS only from there. Not "do whatever you want and spend least RCS on it"

[Alchemist]

Kasuha is right, this is mostly about who can make the smallest ship. I'm not very interested in that.

Just a video to show off, made it a little harder than it was required, tell Scott Manley I give free lessons.

Congratulations on the first successful entry! And pretty impressive, too!

RCS fuel spent: 103

Mass of the craft (since you didn't show it, I recreated the craft to check): 18 t

End score:5.72

Last video I missclicked M instead of N and that turned the navball on, but I didn't had the station set as target, so I don't think it matters. But made another video just in case

Not a problem. The rule about the map during docking is only because it can be abused to estimate and compensate relative velocity.

Still your first attempt is better.

[KvickFlygarn87]

Just make a scenario, starting with a pod in a 75*75 orbit and the station in, say, 250*250. Have a plentiful fuel reserve and disallow LFO to be used within 500m of the station (using the rules of the challenge). Simple as pie!

[Alchemist]

I'm pretty sure Dzhanibekov did not use his main engine anywhere near the station. So I am sensing certain divergence between the "replicate the most daring docking operation" idea and actual rules. If we should replicate that, we should be put on trajectory which gets us somewhere near the station and take on it using RCS only from there. Not "do whatever you want and spend least RCS on it"

There's big difference between modern and older Soyuz. Modern versions (since Soyuz-TM used for Mir) have bipropellant RCS feeding from engine's tank - with these it's most efficient to stay aligned and use linear RCS. With older ones (Including Soyuz-T, despite it being the first of the new series), however, it was the usual procedure to use 90 degree turns and small pulses from main engine during approach to stay on target, the linear RCS were used only during last minutes. Peroxide RCS never had enough delta v for any extensive maneuvering. Of course, you wouldn't point your main engine to the station, but other than that... "ÑÂñûøöðющõ-úþррõúтøрующøù ôòøóðтõûь" means that it was not only for orbit corrections, but also for maneuvering when approaching the station.

[Kasuha]

I still think some kind of common starting point would make this challenge better because it would allow more reliable comparison of results.

Anyway: here is my attempt, using adapted Kerbal X (with docking port instead of chute) and no monopropellant used.

I switched to visual steering 14 km away from the station. Rendezvous was quite simple, docking took a while as you can see on MET timer up till next to last image (in the last image it's the station's timer).

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[Cmdr. Arn1e]

um, how is it possible to dock with an un-kerballed (or non-robotic) space station in KSP? I thought there HAD to be at least one crew member aboard or a remote-unit...

Having said that, .23.5 ARM patch will make it more realistic, in that the 'Claw' can be used instead of a docking port, so you could have a station without crew or remote unit, just drifting in orbit, with a 'real' docking port one side (the 'active' docking port) and just a radial docking connector on the other side as the 'inactive' docking port, and the challenge will be to dock onto the passive port using the claw...

just a couple of ideas that popped into my head while I read comments so far!

[Alchemist]

um, how is it possible to dock with an un-kerballed (or non-robotic) space station in KSP? I thought there HAD to be at least one crew member aboard or a remote-unit...

Having said that, .23.5 ARM patch will make it more realistic, in that the 'Claw' can be used instead of a docking port, so you could have a station without crew or remote unit, just drifting in orbit, with a 'real' docking port one side (the 'active' docking port) and just a radial docking connector on the other side as the 'inactive' docking port, and the challenge will be to dock onto the passive port using the claw...

just a couple of ideas that popped into my head while I read comments so far!

If it has a docking port you can dock to it. Even if that's a piece of debris.

And no, this is not about the claw.