Farscape Atmospheric push maneuver?!

[Arugela]

Is it possible to do the maneuver from Farscape where you glide across the atmospheres surface and push into deep space in this game? Or in general for that matter?

[Randazzo]

AFAIK, you cannot bounce off atmosphere in KSP. If you do hit it, all it will do is slow you down, unless you have DRE, in which case it might rip your ship apart.

You can perform low gravity assist maneuvers to slingshot yourself out of a SOI, but I have no idea if that's what the farscape maneuver is.

[Alshain]

Is it possible to do the maneuver from Farscape where you glide across the atmospheres surface and push into deep space in this game? Or in general for that matter?

Not really, no. While you can come in too shallow and bounce off the atmosphere*. Any trip through the atmosphere will eventually see you back in the same place re-entering the atmosphere in the next orbit (unless you are already traveling fast enough to leave orbit, but I'm assuming that isn't the question). The only way to be ejected into deep space would be to encounter another body like the Mun or Minmus and get a gravity assist.

However, if you are in orbit of Kerbin below the orbit of the Mun and encounter the atmosphere at ANY angle you will either re-enter or go around for another orbit, possibly a shorter one due to aerobraking.

*The phrase "bouncing off the atmosphere" is an old phrase that doesn't technically mean bouncing off anything. It just means you will be too shallow to successfully re-enter.

Edited April 24, 2015 by Alshain

[EtherDragon]

Not really, no. While you can come in too shallow and bounce off the atmosphere*. Any trip through the atmosphere will eventually see you back in the same place re-entering the atmosphere in the next orbit (unless you are already traveling fast enough to leave orbit, but I'm assuming that isn't the question). The only way to be ejected into deep space would be to encounter another body like the Mun or Minmus and get a gravity assist.

However, if you are in orbit of Kerbin below the orbit of the Mun and encounter the atmosphere at ANY angle you will either re-enter or go around for another orbit, possibly a shorter one due to aerobraking.

*The phrase "bouncing off the atmosphere" is an old phrase that doesn't technically mean bouncing off anything. It just means you will be too shallow to successfully re-enter.

Actually skip reentries wouldn't have been a problem for the vessel, at all. In fact it would have been more graceful and heat-friendly, especially for the Apollo missions returning from the moon. The issue cames because the capsule had limited supplies of power and CO2 scrubber capacity, and a skip would have taken too long for the batteries and crew to safely survive.

[Randazzo]

Hypersonic Waveriders utilize atmospheric skipping to travel farther than possible with ballistic reentry while expending no extra energy to do so. The word used to describe it really doesn't matter.

They will, as mentioned, ultimately reenter, but the elasticity of the atmosphere exerts a force on the craft allowing it to "skip" off.

[Hodo]

The "Farscape atmosphere push" maneuver would only work in RO RSS. Where the scales and gravities are the correct scale. Basically the idea is you come into a gravitic SOI at a really steep angle where your PE is just within the atmosphere of the largest gravity body, and use that acceleration to overcome the loss of velocity from atmospheric drag, and slingshot yourself back out into space.

[KerikBalm]

What?

I have no idea what thi Farscape thing is... but this makes no sense:

Basically the idea is you come into a gravitic SOI at a really steep angle where your PE is just within the atmosphere of the largest gravity body, and use that acceleration to overcome the loss of velocity from atmospheric drag, and slingshot yourself back out into space.

Do you basically mean that you fail to aerocapture?

I've had multiple failed aerocaptures at Duna when I come in from a really fast trajectory (like using 4km/s from LKO, instead of the 1 km/s needed when doing it at the proper transfer window).

But that doesn't sound like what the OP is describing... but if I had to guess, what the OP is describing sounds like impossible BS from a soft-sci-fi game

[Alshain]

Actually skip reentries wouldn't have been a problem for the vessel, at all. In fact it would have been more graceful and heat-friendly, especially for the Apollo missions returning from the moon. The issue cames because the capsule had limited supplies of power and CO2 scrubber capacity, and a skip would have taken too long for the batteries and crew to safely survive.

I am honestly not sure what in the world you are talking about. What vessel? The Farscape vessel?

[Arugela]

Farscape was a Sci fi show from around the turn of the century. It's premised around a 20 something(I think) who works at NASA "IASA"(I = International) and was doing a project to use the earths atmosphere to escape into deep space. It revolves around his friends theory(DK?!), who also works at IASA, which has something to do with the idea that if you correctly dive into an atmosphere you could pull back off and get enough energy to go into deep space or out into the solar system with virtually no fuel. In one of the episodes they finally do it on the ship "Moya" and it works. I was curious if it's realistic or worked in this game. It's not aerobraking. It's the opposite.

I was trying to find the clip of Moya diving past the command carrier and going into the atmosphere to escape. But I couldn't find it. In the show the first episode starts with the main character "John" doing this maneuver also.

http://www.henson.com/fantasy_scifi.php?content=farscape

Thinking about it, the module he was in was very small. I wonder if you would need a very tiny ship with very fast acceleration.

As you may or not be able to tell form the video, he got much farther into deep space than he imagined. 8)

The preview of this video goes into the dialogue describing the test.

Edited April 25, 2015 by Arugela

[BDelacroix]

The actors are my age and when the show came out I was around 30. If they were portraying younger people, well they did a good job appearing 10 years younger.

Regardless, I was always suspicious of that maneuver as it sounds impossible. Hitting the atmosphere would bleed energy. Gravity would indeed pull you but you can't create energy. You have a force decreasing your velocity (atmospheric buffeting) you aren't using thrust from your engine (or else it isn't a fuel less maneuver). All you have is gravity pulling you, but not at a direct vector toward the center so some of that energy is lost in altering your vector (unless you used some fuel to keep the vector relatively straight). If you keep a straight vector, your lose energy pulling you due to the distance squared rule. Luckily the show only used it as a ploy to get John to where he needed to be for the story arc. They used it only that one time to get him there and once with Moya and then dropped the whole idea as it served its purpose.

You don't get anything for free.

However, if you try it and end up in a wormhole and meet a good looking valkyrie, good on ya and enjoy the adventures. PS: don't lead the bad people back here.

[Arugela]

I don't think it was fueless. Just used alot less. In the video his module is using an engine in the back to go quick fast. And Moya is a very big powerful ship. It was definitely applying force.

Edited April 25, 2015 by Arugela

[impyre]

You *could* bounce out if using NEAR/FAR... but as others have said, it would still just slow you down a little... wouldn't speed you up or benefit you in any real way. The only time I can think that this might be useful is if you're highly elliptical and need to rotate your orbit around to get an encounter... and you wanted to do it as cheaply as possible. Bouncing out of atmosphere is somewhat like performing radial-out burn. Not sure if it'd actually save you any fuel, but it could be handy.

[KerikBalm]

Yea... that farscape thing makes no sense and was impossible...

[Admac]

Yeah, the show is great, and I'm a fan but the science isn't science. anytime you touch an atmosphere you lose energy, there is no way to make it a positive.

Other things that would be SUPER hard to also do in Kerbal;

-They land on planets by thrusting prograde

-The encounter things in interstellar space, with a relative velocity in the 10s of m/s (motras!)

-They can go from orbit to a specific spot on a planet in under a minute (that implies 8-15km/s->0 in just a few seconds)

-Peacekeepers dock while the command carrier has primary engines thrusting

Short answer is all sci fi is guilty of a lot of bad orbital mechanics, since it's not written by people that really know space science.

[Srpadget]

Basic rule of thumb: If you see ANYTHING in a fictional movie or TV show that involves using SCIENCE! to get the heroes either into or out of trouble, you should always assume the Hollywood writers got it wrong. And do NOT try it at home.