Lithobraking in 1.05

[PPR]

After some testing, I've found the airbrakes make lithobraking  a real possibility. When de-orbiting, if you deploy air brakes immediately upon entering the atmosphere it reduces the increase in velocity from gravity to the point where heat shields are not needed.  While they do not reduce ground impacts to the point where kerbals would survive, with the proper design one can land a probe with no parachutes or engines.  The craft I've used have landed at less than 30 m/s & survived.  A set of landing gear or a sturdy landing structural will both work.

Parachutes may be more useful for a soft landing, but the air brakes have some advantages:

1) Reusable

2) Instant deployment

3) Reduces mass.

4) Deployable at any altitude.

5) Reduces re-entry heating

As for disadvantages, they require more parts to work effectively, are bulky, and tend to be more expensive.  They don't work well for crewed or heavy craft.

But now it's viable a design option.  I've only tried it on Kerbin, but I look forward to testing it on Eve.

[RA3236]

What you are talking about is aerobraking, not lithobraking.

Lithobraking is using the planets surface to slow down, aerobraking is using the atmosphere.

[problemecium]

^ Actually he IS talking about lithobraking, if you read all the way to the end.

Anyway, parachutes are also reusable if you have a Kerbal aboard: it can EVA, go near the parachutes, and use the right-click menu to repack them. I think it needs to be an Engineer to do this.

Also, air brakes can be deployed at any altitude, but not really at any speed. If you're going too fast and too low, they can easily overheat and blow off, as I've had occur on several occasions.

[Moar Boosters]

Well every landing has a small amount of lithobraking at the end. If the technique doesn't work on non-atmospheric bodies it's not really lithobraking.

[sardia]

Don't be a hater, it's pretty cool. 

[PPR]

Try it.  It's an interesting option.

[PPR]

For the record:

 

Lithobraking is a landing technique used by unmanned space vehicles to safely reach the surface of a celestial body while reducing landing speed by impact with the body's surface. (Wikipedia)

It can use parachutes, rockets, airbags, shock absorbers, or airbraking to reduce speed prior to impact.  It applies to bodies with or without atmospheres, which may require different techniques for reducing speed.

As for losing the airbrakes, if you deploy them at 70km, they won't break because the atmosphere is too thin,  but speed is still reduced.  By the time you get deep enough into the atmosphere where heating/pressure would become a problem, your speed has been reduced enough where it isn't.

That aside, it actually pretty fun--which is kind of the point of KSP.  Like I said, try it.

[FancyMouse]

Looking forward to your Eve testing. My old 1.0.4 testing showed that airbrakes are completely useless for Eve at interplanetary speed because they're the first part to explode. They explode way before they become effective. I doubt this changes in 1.0.5, but still need testing to confirm.

[fourfa]

The original post is about de-orbiting, not capturing from interplanetary speed?  In my experience so far, they definitely have a place in de-orbiting to Eve, even though they may not survive being deployed 100% of the way down.  Try cycling on and off as needed.

[PPR]

Just tried it one Eve.  Worked even better.  The airbrakes worked so well I was able to microwave a couple of potato skins while waiting for it to land (and let them cool off enough to eat).  The Airbrakes did heat up in the upper atmosphere enough for me to worry, but nothing was destroyed.  Only  one of the four landing gears was even damaged.

 

Next goal: Duna!

Edited February 6, 2016 by PPR

[AbacusWizard]

I have occasionally used lithobraking to kill horizontal velocity when landing on the flats of Minmus. Come in from a really low suborbital trajectory, use engines and/or RCS to decrease vertical velocity to almost zero, extend landing gear, touch down gently and commence rolling forward at high speed, use brakes (gently!) to gradually slow down and stop. Works pretty well, and if the craft is designed right it can take off from a rolling start as well.

 

Edited February 6, 2016 by AbacusWizard

[SpaceplaneAddict]

Aerobroke at 115 M/S at Duna using airbrakes, and many structural parts, here!

[PPR]

Okay, Lithobraking at 115 m/s with a kerbal surviving?  That was amazing!

[Number R09]

Soo.. aerobraking enough to land vertically at a safe speed.  If you are lithobraking vertically for zero seconds, we call that type of lithobrake, landed.  Otherwise, skidding across the ground, by wheels or other means, to lose the last amount of horizontal movement after impact would be lithobraking.