Lowest Kerbin Periapsis

[Bioman222]

Title explains most of it. Basically, you need to achieve the lowest periapsis possible over Kerbin.

Rules:

1. You must be able to perform at least one full orbit with the periapsis without firing engines on your spacecraft

2. It can be inside the atmosphere

3.The apoapsis must be outside Kerbin's atmosphere.

4. Videos preferred, but multiple screenshots are okay,

5. No use of wings or control surfaces when orbiting.

6. No hyper edit!

7. You must be flying the ship when it goes through the periapsis.

Leader board:

1. mstrfalco, 26,301 m

2.

3.

4.

5.

Happy Flying!

Edited July 28, 2014 by Bioman222
Rule edit, since YOLO

[JacobT11]

I'd say this needs to be really refined. Can I drop my orbit to 1km, and then fire my engines to make sure I maintain the periapsis?

[Bioman222]

Good point. Edited.

[Dave Kerbin]

I'd say this needs to be really refined. Can I drop my orbit to 1km, and then fire my engines to make sure I maintain the periapsis?

For that matter can I attach control surfaces. What is the difference between an 'orbit' and simply gliding/infiniti-gliding around the planet with a one time dip down to 10m above the ground?

[Deejay2000]

For that matter can I attach control surfaces. What is the difference between an 'orbit' and simply gliding/infiniti-gliding around the planet with a one time dip down to 10m above the ground?

There should probably be a rule that the apoapsis can never fall into the atmosphere.

[kagurazaki]

I would vote against using wings to maintain the ship, just using trajectory's and speed should be a much betterg challange

[Bioman222]

OK, will add those things.

[Bioman222]

K, edited.

[m00nchile]

One more tip, you should always be flying the ship that does the challenge. Otherwise I can set a PE just above the ground, exit to the tracking station and the ship will be put on rails, IE not slowed down by the atmosphere.

[LostOblivion]

One more tip, you should always be flying the ship that does the challenge. Otherwise I can set a PE just above the ground, exit to the tracking station and the ship will be put on rails, IE not slowed down by the atmosphere.

Won't that cause the ship to despawn when going below 23000?

I guess the best way to do this is using a pod, aiming it so that it will generate some lift. No wing, just lift.

[Bioman222]

One more tip, you should always be flying the ship that does the challenge. Otherwise I can set a PE just above the ground, exit to the tracking station and the ship will be put on rails, IE not slowed down by the atmosphere.

Edited. 10char

[mstrfalco]

Initial Pe: 26,301m Ap: 82,525,434m

Lowest point craft reaches: 25,584m

Final Pe: Below surface Ap: 72,172m

Javascript is disabled. View full album

Edited July 28, 2014 by mstrfalco

[Cmdr. Arn1e]

My attempt: Imgur Album

Initial Pe: 26,301m Ap: 82,525,434m

Lowest point craft reaches: 25,584m

Final Pe: Below surface Ap: 72,172m

Broken one of the rules; You have entered the Atmosphere (ends at 69.something...) which is the most achievable with this challenge... so IMO, not really a challenge...

[mstrfalco]

Broken one of the rules; You have entered the Atmosphere (ends at 69.something...) which is the most achievable with this challenge... so IMO, not really a challenge...

Umm.. try hitting the next key again buddy. There are two more screenshots of it going up over 72 km that clearly show the Ap above the atmosphere. The screenshot you are referring too was just near the transition point. the atmosphere ends at (~69,077.553 m)

EDIT: Also I think you are confused. In the OP it says Pe may be in atmosphere, Ap may not. As well you must only complete one orbit, obviously the only stable orbit is above 69 km but that is not what the challenge is about.

Edited July 28, 2014 by mstrfalco

[Bioman222]

Nevermind.

Edited July 28, 2014 by Bioman222

[zarakon]

I guess the best way to do this is using a pod, aiming it so that it will generate some lift. No wing, just lift.

Pods don't generate lift

At least not in stock, and I would assume physics mods are not allowed, since they would completely change the playing field

[Mr Shifty]

My attempt: Imgur Album

Initial Pe: 26,301m Ap: 82,525,434m

Lowest point craft reaches: 25,584m

Final Pe: Below surface Ap: 72,172m

This is probably pretty close to the best you can do without an initial hyperbolic orbit. Can you start with a hyperbolic orbit? How do you count a full orbit? Maybe as long as you both enter and leave the atmosphere with an Ap above 70km.

[mstrfalco]

This is probably pretty close to the best you can do without an initial hyperbolic orbit. Can you start with a hyperbolic orbit? How do you count a full orbit? Maybe as long as you both enter and leave the atmosphere with an Ap above 70km.

I would be quite impressed if someone could top my attempt. You can't have the Ap leave kerbin's SOI so no hyperbolic orbits. The Ap I had was so close to an escape trajectory I could probably only improve Pe velocity by +0.3 m/s or so. Also the final orbit was very very sensitive to initial conditions, changing the initial pe by about 250m would often lower the final Ap by 50 km. So I had many attempts before I had one I was really happy with (pretty lucky too). Also the "Ship" I made was the lowest drag craft I could conceive without using wings or control surfaces.

Also Bioman222, you have a typo in the OP. my initial PE was 26,301 not 26,031.

Thanks,

~Falco

[zarakon]

I think there are a few other parts that would give slightly lower drag. According to the wiki, the chair is 0.05. FL-A5 Adapter is 0.04, Small Hardpoint is 0.02, and LT-5 Micro Landing Strut is 0.015. There are some other parts that are listed even lower, but they are the "weightless" parts that I think actually get treated as 0.2

[mstrfalco]

I think there are a few other parts that would give slightly lower drag. According to the wiki, the chair is 0.05. FL-A5 Adapter is 0.04, Small Hardpoint is 0.02, and LT-5 Micro Landing Strut is 0.015. There are some other parts that are listed even lower, but they are the "weightless" parts that I think actually get treated as 0.2

Wiki is a bit out of date. P.S. I did use the chair xD. Anyways the FL-A5 adapter is now "weightless"/"physics-less" and drag 0.2, Small Harpoint is 0.2 same with the landing strut. And you are spot on the physics-less parts are treated as 0.2 drag.

[Cmdr. Arn1e]

Hmmm, see your point, as you say, don't think that can be beaten very easily - hence not really a challenge, once someone has achieved the best, it's all over, and I think we already have our winner...

[Bioman222]

You know, things could get screwy if I allow hyperbolic trajectories...

Lets do it!

[MarvinKitFox]

If you allow true hyperbolic entry, I have a picture here somewhere with a Pe of -417km, with me at -233km...

Taken while doing a 55km/s flyby.

Seems the fizzics engine doesn't detect a collision if you pass through the atmosphere in less than one physics tick.

[Mr Shifty]

If you allow true hyperbolic entry, I have a picture here somewhere with a Pe of -417km, with me at -233km...

Taken while doing a 55km/s flyby.

Seems the fizzics engine doesn't detect a collision if you pass through the atmosphere in less than one physics tick.

To prevent this, you'd just have to specify that the Ap after passing by Kerbin must be inside Kerbin's SOI, i.e. if you start with a hyperbolic trajectory, it must be slow enough to allow for aerocapture.

[Bioman222]

If you allow true hyperbolic entry, I have a picture here somewhere with a Pe of -417km, with me at -233km...

Taken while doing a 55km/s flyby.

Seems the fizzics engine doesn't detect a collision if you pass through the atmosphere in less than one physics tick.

I want to see these pics.