Kergarin

The history of Eve SSTOs and reusables

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The history of Eve SSTOs and reusables

For a long time it was said, Eve SSTOs are impossible.

Even going there and back reusable was unthinkable.

But then a hand full of brave Kerbonauts put all their efforts in proving this wrong.

 

This is their story.

 

03.09.2015 - V1.0.4 - First SSTO plane from Eve's surface to Orbit

@astrobond was the first to do the impossible. He created this SSTO which was capable of getting from surface to orbit using stock parts and physics. To stay in the narrow margin, the control was given to KOS.

 

05.07.2016 - V1.1.3(?) - First reusable trip from Kerbin to Eve's surface and back

@Stratzenblitz75 was the first who managed to do the entire trip from Kerbin to Eve's surface and back completely reusable. He is using a spectacular and never seen before suborbital catch of the lander, as well as massive SSTO launch systems.

 

19.08.2016 - V1.1.3 - SSTO rocket from Eve's surface to Orbit

@Kergarin (I) was inspired and motivated by @astrobond's SSTO to start playing around with different SSTO designs. Coming to the conclusion, that SSTO rockets actually seem to work better than planes, giving a larger margin and payload.

 

23.08.2016 - V1.1.3 - First SSTO Lander from Eve's orbit to surface and back 

@Kergarin (I) was then able to scale it up to a bigger version, with enough payload to equip it with isru and seats for all our 4 brave Kerbals. Resulting in the first ever SSTO wich can not only launch from Eve but also land on its own in one piece. By being refuelled in low Eve orbit, this craft could have done the entire trip Kerbin to Eve and back reusable. My plan was, to do a reusable trip to all landable bodys in the Kerbol system based on this lander plus an orbiter, but this plan should be crossed soon...

 

11.10.2016 - KSP 1.2 release - an increase in Eve's atmospheric pressure changes the rules

The pressure of Eve's atmosphere was increased, resulting in even higher drag and giving all engines lower thrust and Isp, making Eve SSTOs even harder... it seemed. 

The change in the Mammoth engine thrust for example:

S7xD9DN.jpg

For reference Eve's atmospheric pressure in 1.2.2:

mHeS8LL.png

After this change my SSTO lander stopped working, at least with the needed payload for ISRU.

While the change in pressure made SSTO rockets harder, it will soon turn out that SSTO planes now work better again.

 

29.10.2016 - V1.2.2 - the first asteroid refuelling assisted SSTO plane from Kerbin to Eve's surface and back

@EvermoreAlpaca built this craft initially in 1.1.3., and when 1.2 came out, this plane worked even better, opposed to SSTO rockets. This craft can get from Kerbin to Eve's surface and back to Eve's orbit independent. It then needs orbital refuelling, to get back to kerbin, which is realized by the craft itself moving an asteroid to low Eve orbit in before, which is then used for ISRU refuelling.

 

28.01.2017 - V1.2.2 - SSTO rocket from Eve's surface to orbit achieved again

@Kergarin (I) managed to make my small SSTO rocket work again in 1.2.2. But scaling it up did not work as good as back in previous versions. The ISRU lander would have become unhandleable large. So I cancelled this concept.

 

20.05.2017 - V1.2.2 - infinitely reusable trip to Eve (and first ever to everywhere else) and back

Since my Eve SSTO lander doesn't work in 1.2.2 anymore (and I didn't want to do this in an old version), I adoptet @Stratzenblitz75's concept of suborbital docking and developed it to a single ISRU ship wich splits in two for the Eve landing with his friendly permission (thanks again!). (Creating the first ever ship which can independently and forever travel between all 14 landable bodys. But that's on another page.)

Skip to 3:40 for Eve landing (caution: flickering scenes in fast forward)

 

07.03.2018 - V1.3.1 - smallest ever SSTO plane from Eve's surface to orbit

@astrobond the creator of the first ever Eve SSTO comes back to the game. Presenting us the smallest ever seen Eve SSTO. Also it's the first not to use the Mammoth engine, but the Vector with a slightly lower twr.

 

11.06.2018 - V1.3.1 - reusable two stage plane from Eve's surface to orbit and back to surface

@OHara created this reusable two stage plane, which can be used for crew rotations of 4 Kerbals per flight. It launches horizontal and then transitions to vertical ascend pushing the ap far above Eve's atmosphere. The second stage then undocks and accelerates to orbital speed before the first stage reenters and glides back to its starting position. The second stage can also be landed and then redocked to the first stage. The craft then needs some external refueling to be reused.

hY9vhWM.jpg

Spoiler

Original post:

PelicanFish.jpg

I am happiestmyself with a two-stage design (craft file) using horizontal takeoff and landing forthe sake ofcontrol, especially for the landings.

 Fueled mass is 175 tonnes and TWR starts at 1.1 at Eve's high-point.  I can hold an AoAaround 3° and gradually transition to vertical.  I take off heading west, then rotate just past vertical to exit the atmosphere, so that the first-stage re-enters not toofar east of thehigh-point, withingliding distancefor landing, without needing to save any fuel for boost-back.  

The second stage then needs to provide essentially all the orbital speed to circularize, but it can do so with 2--4 G acceleration before the first stage gets too deep in the atmosphere, so I can switch back to land the first stage, without any stage-recovery mods.  The orbital stage took its canard with it, so the booster stage is left with wings further back, closer to its unfueled CoM.

When it is time for the orbital stage to return to the surface, it has wing-strakes forming a feathered tail and deployable control surfaces for drag, all of which were shielded in the cargo ramp during ascent.

For re-docking, both craft point slightly uphill, the orbiter rolls into the cargo ramp, and then the lifter gulps it down, like a pelican swallowing a fish.  The module-manager patch to enable angle-snap on docking ports is very helpful to make the joined craft fly straight.  After docking, the cargo ramp can close around the orbiter, shielding its tail feathers and engine from drag during the next ascent, but leaving its nose and canard active (and causing drag, which is only fair).  I am happy to imagine this is some custom fairing that the Kerbals can fit while they are preparing the craft for flight.

Not that I'm finally happy with the shuttle in 'the simulator' (hyperedit) I can time-warp to the transfer window and send the full expedition.

 

 

29.10.2018 - V1.5 - First completely independent SSTO plane from Kerbin to Eve and back

SSTOs to Eve's surface and back to orbit were now proven to be possible, and they seemed to be the limit of possibilities. All of them need some kind of orbital refuelling or catch to escape from low Eve orbit.

But then @EvermoreAlpaca did the unthinkable. A massive independent SSTO from Kerbin to Eve's surface and back to Kerbin. He managed to raise the payload on Eve ascend that much, that there was enough margin to fit an ion drive with enough dV to escape Eve's gravity and then send the ship back to Kerbin using some gravity assists, without any dependencys.

 

04.12.2018 - V1.5 - First stock electric prop SSTO plane from Eve's orbit to sea level and back to orbit (plus from and to Kerbin by external refuelling)

@EvermoreAlpaca continues doing the impossible by presenting us this stock electric propeller assisted Eve sea level SSTO. It ascends from sea level to above 19km sole on electric props, then continues its way to orbit on conventional rocket engines.

It can also launch and land at Kerbin, but needs external refueling to do so.

This craft uses clipping for the stock props as well as engine clipping, but is honored in this list for being the first of its kind. 

 

 

28.01.2020 - V1.8.1 (+ Making History + Breaking Ground) - First Breaking Ground electric prop multi engine SSTO plane from Eve's orbit to sea level and back to orbit

@realseek was the first to show us a working sea level SSTO using electric rotors and blades from Breaking Ground, packed into cargo-bays to reduce their drag, after switching to rocket engines.
It reaches 16km on electric props (two EM-64S rotos with 16x R25 blades on each. The rotors run at 60% power and a max RPM of 400).
To escape Eve's still dense atmosphere, it uses a combination of 3 Vector engines and 2 Nervs to circularize.
As if an Eve sea level SSTO would not be enough, this craft can land fully fuelled from orbit , also carries the extra weight of ISRU
quipment without even needing it, because it can launch from Eve below 100% fuel and stiff make it to orbit with hundreds of m/s dV left to spare, while the craft even looks good. This is just insane!
More pictures and details: 
https://imgur.com/gallery/afVyAv1
 

 

 

15.02.2020 - - V1.8.1 (+ Making History + Breaking Ground) - minimalistic Breaking Ground electric prop single engine SSTO plane from Eve's orbit to sea level and back to orbit (+ to and from Kerbin with a separate tug)

@Kergarin i was a little to slow on this, and humbly take the second place.
Props alone work great, and rockets alone work great. But in combination the drag of props after igniting the rockets is horrible.
The way to deal with this, is placing them inside cargo bays, to shield their drag when they are not used.
It would be beautiful to use hydraulic cylinders to make them stick out, and while this would be possible in term of weight and drag, they sadly the flex way to much to even lift off.
I've tried a lot of designs for this since BG came out, and while @realseek found the mixed engine design work best for him, I found a single enige design work best for me.
This craft uses two EM-32 Rotors with 6 R25 blades on each which run at 100% torque and max RPM to climb to 17km.
To escape the dense atmosphere, this craft uses a single vector Engine on full thrust, and then carefully throttle adjustment to not overheat and circularize.
This was done as grand finale in my reusable career playthrough:

 

28.05.2020 1.9.1(?) First stock (no DLC) electric prop SSTO helicopter rocket to sealevel and back without clipping (+ from Kerbin and back)

@Stratzenblitz75 returned to Eve, almost 4 years after he was the first to do a completely reusable roundtrip from Kerbin to Eve and back using suborbital docking. 

This time he uses an SSTO rocket which is first lifted by insanely large counter rotating koaxial like props to 39km, and then ignited to get to orbit on rocket power in a single stage. 

The props consist of stock bearings, but they are not powered by the usual way of using reaction wheels. To reach the record height of 39km, large rover wheels power the props, which is obviously way more efficient.

The craft features ISRU, and can therefore land and launch unlimited often and completely independent on Eve.

The craft takes of from Kerbin using a single reusable launcher, and is pushed to Eve and back by an orbiter. 

 

 

 

This far Kerbalkind conquered the purple monster as of the middle of 2020.

Can they go even further? 

 

 

 

Disclaimer:

Spoiler

This was made to have a reference for the steadily upcoming question and challenges for Eve SSTO.

I did not plan to write a this large thread, but somehow this escalated quickly. :D (well, 5 hours actually)

It was made by my best knowing and interpretation. Please correct me if I got something wrong or missed something.

I'm pretty sure, there was a reusable two stage launcher, with a safe landing first stage and orbiter. But I can't actually find it.

The text actually is dominated by my approaches, naturally because I can tell more about my own experiences. Please let me know, if I should change or add something, or change it to your personal story and view. I hope that's ok to you all?

@astrobond @Stratzenblitz75 @EvermoreAlpaca

 

 

 

Edited by Kergarin

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Hi @Kergarin and all :)

More than ok for me, it's a very good idea to put all the Eve's SSTO videos on a single story trade !!!

Thank you very much for this excellent work :D 

Fly safe with Valentina ;)

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Hi @astrobond glad you like it :)

The newest Eve SSTO challenge brought me to this idea.

If you want me to add or change something, or write your own description, just let me know. :)

Edited by Kergarin

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Thanks for taking the time to find and explain all these missions. I think lots of people will be interested to read it.

1 hour ago, Kergarin said:

I'm pretty sure, there was a reusable two stage launcher, with a safe landing first stage and orbiter. But I can't actually find it.

There was a thread on re-usable staged craft about one year ago.  Using two stages opens up a lot of choices, in stock KSP.

 

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1 hour ago, Kergarin said:

Hi @astrobond glad you like it :)

The newest Eve SSTO challenge brought me to this idea.

If you want me to add or change something, or write your own description, just let me know. :)

'Challenge'. I feel a little dim for posting that thread now. I will try not to underestimate this player base ever again lol.

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8 minutes ago, M_Rat13 said:

'Challenge'. I feel a little dim for posting that thread now. I will try not to underestimate this player base ever again lol.

Don't mind, this challenge comes up a few times every year, and sometimes it still leads to new achievemets. As you can see, the newest achievement is just 4 month old. So who knows what will happen this time. :)

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14 minutes ago, M_Rat13 said:

'Challenge'. I feel a little dim for posting that thread now. I will try not to underestimate this player base ever again lol.

To be fair, Eve SSTOs were thought to be impossible in vanilla KSP for the longest time. It was the holy grail. You're not wrong in your line of thinking, you're just a bit late.

The question becomes, what is the holy grail now? Jool SSTO?

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4 minutes ago, Ultimate Steve said:

To be fair, Eve SSTOs were thought to be impossible in vanilla KSP for the longest time. It was the holy grail. You're not wrong in your line of thinking, you're just a bit late.

The question becomes, what is the holy grail now? Jool SSTO?

I only recently came back to KSP, so yes, I have some catching up to do.

Also, while there is the Jool 5 mission, I have yet to see someone do it in one launch/craft ;)

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1 minute ago, M_Rat13 said:

Also, while there is the Jool 5 mission, I have yet to see someone do it in one launch/craft ;)

That's been frequently done. I think someone managed it under 20 tons, using lots and lots of ion engines... I did a similar mission once where I visited the moons of Jool and the moons of another gas giant (modded) in one launch, but with refueling.

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Just now, Ultimate Steve said:

That's been frequently done. I think someone managed it under 20 tons, using lots and lots of ion engines... I did a similar mission once where I visited the moons of Jool and the moons of another gas giant (modded) in one launch, but with refueling.

Again, I'm a little behind. I need to start thinking more extravagant...

My challenge will be to challenge others lol.

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1 hour ago, OHara said:

Thanks for taking the time to find and explain all these missions. I think lots of people will be interested to read it.

There was a thread on re-usable staged craft about one year ago.  Using two stages opens up a lot of choices, in stock KSP.

 

That's what I was looking for :D

I hope you don't mind I have added it to the list? Please check if I should change something.

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 It is important to note that the level of aerodynamic trickery employed greatly impacts the level of challenge here.  With full abuse of fairing occlusion, a chemical rocket single stage from sea level is more than possible.  I mostly refrained from this with my propeller assisted single stage from sea level, but still used fairing occlusion for the chemical engines specifically.  A craft that can do single stage from sea level without the use of ANY abusive fairing occlusion would merit a new and distinct achievement.

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On 3/29/2019 at 7:37 PM, EvermoreAlpaca said:

 It is important to note that the level of aerodynamic trickery employed greatly impacts the level of challenge here.  With full abuse of fairing occlusion, a chemical rocket single stage from sea level is more than possible.  I mostly refrained from this with my propeller assisted single stage from sea level, but still used fairing occlusion for the chemical engines specifically.  A craft that can do single stage from sea level without the use of ANY abusive fairing occlusion would merit a new and distinct achievement.

The only way I could imagine to do this, is optimizing your stock prop design. I don't know if that's even possible.

Seabed return would be next. :D

 Also landing a fully fuelled SSTO from orbit which can return to orbit without ISRU or any other refuelling at the ground would be a verry interesting achievement.

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After weeks of tuning and design work, I humbly submit my own creation in this topic:

A Single Stage To Orbit that can take off from Eve at sea level. This is made possible by using propellers from Breaking Ground to first climb out of the thick atmosphere. The SSTO is fully functional, contains ISRU, seats for two Kerbals, science equipment and two LV-Ns for interplanetary travel. It can land fully fuelled and has infinite range inside Eve's atmosphere. No modded parts, clipping or aerodynamic trickery was used.

Leaving a small amount of LF in orbit around Eve and refuelling on the surface, it should be possible to do a full round trip from Kerbin to Eve's oceans and back.

 

Hope you will find this interesting, as this is the first time I made a video to share!

https://www.youtube.com/watch?v=FSzZ4CYb0LE

Edited by realseek

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18 hours ago, realseek said:

After weeks of tuning and design work, I humbly submit my own creation in this topic:

A Single Stage To Orbit that can take of from Eve at sea level. This is made possible by using propellers from Breaking Ground to first climb out of the thick atmosphere. The SSTO is fully functional, contains ISRU, seats for two Kerbals, science equipment and two LV-Ns for interplanetary travel. It can land fully fueled and has infinite range inside Eve's atmosphere. No modded parts, clipping or aerodynamic trickery was used.

Leaving a small amout of LF in orbit around Eve and refuelling on the surface, it should be possible to do a full round trip from Kerbin to Eve's oceans and back.

 

Hope you will find this interesting, as this is the first time I made a video to share!

https://www.youtube.com/watch?v=FSzZ4CYb0LE

Amazing! @Kergarin, has this been done before? I mean, this is the first new submission to the thread using either of the DLCs, so I don't believe so!

 

@realseek (welcome to the forums, btw!), you may have just completed a forum first, congrats!

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On 3/24/2019 at 3:56 PM, Ultimate Steve said:

That's been frequently done. I think someone managed it under 20 tons, using lots and lots of ion engines... I did a similar mission once where I visited the moons of Jool and the moons of another gas giant (modded) in one launch, but with refueling.

so what's next, a kerbol SSTO?

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24 minutes ago, Dirkidirk said:

so what's next, a kerbol SSTO?

Not without ignore max temp. I don't think anyone's done a Kerbol ascent vehicle, period. The dynamics of Kebrol's hot atmosphere are also not very well understood.

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4 hours ago, Ultimate Steve said:

Not without ignore max temp. I don't think anyone's done a Kerbol ascent vehicle, period. The dynamics of Kebrol's hot atmosphere are also not very well understood.

I don't know if it's possible at all even with ignore max temp.

Kerbol has 1.75g and you need more than 50km/sec of dv.

Sadly Kerbol will remain the only body in the system that you cannot SSTO from.

Edited by Lt_Duckweed

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On 1/28/2020 at 7:01 PM, Kerballing (Got Dunked On) said:

 

@realseek (welcome to the forums, btw!), you may have just completed a forum first, congrats!

Thanks! This post was very helpful and a big inspiration.

I was already playing around with stock propellers before, but seeing what @EvermoreAlpaca had to go through with his Eve propeller design made me quit... :D
Since Breaking Ground this became viable again because electric motors are so much lighter than dozens of reaction wheels.

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On 1/28/2020 at 12:57 AM, realseek said:

After weeks of tuning and design work, I humbly submit my own creation in this topic:

A Single Stage To Orbit that can take off from Eve at sea level. This is made possible by using propellers from Breaking Ground to first climb out of the thick atmosphere. The SSTO is fully functional, contains ISRU, seats for two Kerbals, science equipment and two LV-Ns for interplanetary travel. It can land fully fuelled and has infinite range inside Eve's atmosphere. No modded parts, clipping or aerodynamic trickery was used.

Leaving a small amount of LF in orbit around Eve and refuelling on the surface, it should be possible to do a full round trip from Kerbin to Eve's oceans and back.

 

Hope you will find this interesting, as this is the first time I made a video to share!

https://www.youtube.com/watch?v=FSzZ4CYb0LE

Welcome to the club and congratulations! :D

Let me recap... You have build an Eve SSTO which can land from orbit fully fuelled, carries the extra weight of ISRU equipment which isn't even needed, than you takeoff with less than 100% fuel and make it to orbit with hundreds of m/s dV left to spare while the craft even looks good, and all this was done in weeks? That's just crazy! :confused:

You achieved definitely something which hasn't been done before!

I will add this to the list as soon as possible!

 

I know how hard this is, and I'm really impressed. I was working on something like this since BG came out. And all I got so far is an ugly single seater which barely and unreliable makes it from and to orbit with no margin for error. Your mixed engine design seems to be the key, mine just uses one type of engines.

What rotors do you use? They seem to have a lot of blades. For mk2 cargo bays I found the middle size rotor with 6 blades to be most efficient. Yours look like 16 or so?

Edited by Kergarin

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Thank you, Kergarin for the kind words and compliments!

It all started for me when a friend gifted BG to me because I did not want buy it initially... it made my stock propeller designs from before seem like toys :/
My first attempt in related crafts were a staged Eve lander, which used propellers for pure vertical ascend, and a Kerbin SSTO with rotating ducted propellers for VTOL. I learned a lot from those.

To answer your questions:
There are 16x R25 blades on each EM-64S motor. The motor is set to 60% power and a max RPM of 400. Testing at 16km on Eve showed that this rpm produced the most thrust, for some reason... The whole motor assembly is placed once in the front and back to help with weight distribution and aerodynamic stability. In total, this is 7 tons of dead weight for the electric stage. Sounds like a lot, but in the end its only 12% of the dry mass...

Aerodynamics optimization and TWR become the most important part once you ignite the rocket engines. Ideally you fly prograde most of the time and let the wings lift the craft out of the atmosphere while gaining decent horizontal speed. For me, the best wing incidence was at 3.5 deg. If your initial TWR is too low, then much fuel is wasted just breaking the sound barrier and climbing above 20km where the air gets thinner. Too high TWR might cause yout to accelerate quickly in the thick atmosphere just to throttle down later, or carry to much engine weight.

I have tried a single engine type before, but could not reach enough dV -- diminishing returns due to high dry weight -- without beeing too heavy to fly up to a decent altitude on electric power.
In the end, it is very tricky... It is possible to end up in a "local maxima" of a design without reaching orbit yet, where the only way to make it any better is to make big breaking changes.

Best of luck with your Eve SSTO attempts! :D

Here is a gallery of my SSTO that shows some more details: https://imgur.com/gallery/afVyAv1
I will upload a craft file later, once I had time to do a complete mission.

 

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@realseek

It's definitely deserved :wink:

Thanks for those details!

Limiting the power is an interesting idea. Have never really tried that and was running on 100% all the time, while testing different numbers of blades to find the smallest possible solution.

I use a single cargo bay for props and have focused on minimizing the weight. It can climb to almost 17km this way and reach orbit with verry little margin. Also the reentry is verry close to the edge of overheating. But it works :D

Wings are straigt forward, and I have to pull up manually. My twr seems a little higher, I have to cut throttle between 30-40kms, but else it wastes to much fuel before I can pull up (as you said too).

It will be shown in part three of my reusable career playthrough, which needs some final video editing. I hope to finish it this or next weekend. 

 

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@realseek
Thanks for the explanations regarding motor size and blade number, wing angle and ascent profile. That was far more fruitful than watching your video over and over again to reverse engineer it. ;)
EVE SSTOs are the holy grail of Kerbal Engineering, it seems. Well done.

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@realseek I've added your craft to the first post.
please check if everything is ok, and let me know, if you want me to change it :)
in wich version was it done? I've added 1.8.1 for now.


I've also finally found the time cut part 3 of my reusable career playthrough, which features my attempt on an electric prop Eve SSTO.
I humbly take the second place behind your amazing craft, with a minimalistic attempt:
 

 

 

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