Returning KSP player with a 1.0.4 re-entry question

[archnem]

Hi all:

I haven't played KSP in a while, since the early days of the 1.0.2 update. I got the itch and started a new career, but now all my craft seem to be exploding on re-entry! Especially the materials bay! I've also noticed that even if something as simple as a surface-mounted battery explodes, it will usually take multiple parts with it. Honestly, I don't really have a problem with this, as I felt re-entry was too "easy mode" before, but after scanning the update notes, I see no mention of this. Plus I seem to remember testing out 1.0.4 with a couple of craft and not having any problems. I just wanted to check and see if re-entry is "for reals" now, or if maybe my install is screwy?

Thanks in advance.

Edited July 20, 2015 by archnem

[mrclucks]

Re entry is harder now. There is also altitudes where if you're going certain speed (interplanetary speeds) then instead of heating up very rapidly, you'll just explode as if you hit a brick wall.

I believe ablator is much more important now. In 1.0.3 it was said that you could return from the mun and even minmus without an ablator shield, but in .4 you need a shield even from the mun. Personally I've always used ablator since reentry hearing became stock, but my ablator is being used alot more in .4 than in .2.

.I do miss .2 in that I could return a probe from jool and even with a periapsis of 10 km, it didn't completely explode as long as I had ablator and was pointing it prograde

[Sharpy]

One simple approach is to always survive (unless you use Life Support and have limited resources...) is to skirt the edge of the atmosphere.

I don't know what would need to happen for Kerbin to kill you with 52km periapsis; if you are within Kerbin orbit you can reduce to 48km and it will keep ejecting you through the other side until you're down to a safe speed. On Eve that's 85km. Aerocapture + landing didn't even use up any ablator with these parameters, although it took a good dozen orbits to finally enter the descent. I don't know about Duna, but I imagine 40km should be quite safe.

Seriously, since 1.0 I never really had any use of heatshields. I just stick to a very shallow periapsis and everything except the most aerodynamic shapes lands just fine (and I stick a pair of airbrakes on the latter, deployed in space they work wonders.)

[Evanitis]

Before 1.0.4 I though that gravity assists are pretty hard and really pro things to do for conserving a bit of dV. Reentry heat made me realize that it's easy and very efficient - even if I don't count that I don't have to take tonnes of heat-shield with me for interplanetary missions.

[Warzouz]

I don't know about Duna, but I imagine 40km should be quite safe.

Coming from Kerbin :

- I did a 25km aerobraking without heatshied at Duna (a space station). I only retracted the solar panels.

- Then I did a 17km aero-braking (engine first) with then "mission" ship (return vehiclke + landers). Temp didn't rise higher than 40% (of the lowest max temp)

Duna aero-braking is safe, even for ships not designed for that.

Finally, landing on Duna from orbit won't even raise temp above 20% (no airbrakes), no flame effect. Regular chutes can be open at 600m/s safely (I didn't try higher speeds). NB : The lander was just a regular Mun lander with 6 radial chutes. dV = 2700m/s, 7.3T, capable of 1 hop on Duna before takeoff.

[FancyMouse]

Duna is a place you really need airbrakes. It's a matter of easy aero landing versus narrow (if not nonexistent) margin of not capturing and too low.

[Reactordrone]

A steep entry in 1.0.4 will put you at risk of exploding, heat shield or no heat shield. The combination of high speed and low altitude will cause a the boundary layer to separate and the turbulent flow will rapidly heat and destroy even the highest temperature rated part. A normal entry with 30-35km periapsis on kerbin should be safe for an unshielded craft and straight up and down sub orbital hops of less than 215km altitude should be safe (but it will leave you with a very narrow window to deploy your parachutes).

Anything to increase your drag to slow you down will increase your safety margin and drogue chutes are quite useful now since they can be deployed safely at 500m/s rather than the 250m/s of the main chutes.

[Godot]

One simple approach is to always survive (unless you use Life Support and have limited resources...) is to skirt the edge of the atmosphere.

I don't know what would need to happen for Kerbin to kill you with 52km periapsis; if you are within Kerbin orbit you can reduce to 48km and it will keep ejecting you through the other side until you're down to a safe speed. On Eve that's 85km. Aerocapture + landing didn't even use up any ablator with these parameters, although it took a good dozen orbits to finally enter the descent. I don't know about Duna, but I imagine 40km should be quite safe.

Seriously, since 1.0 I never really had any use of heatshields. I just stick to a very shallow periapsis and everything except the most aerodynamic shapes lands just fine (and I stick a pair of airbrakes on the latter, deployed in space they work wonders.)

Similarly here ...

I just bring the Apoapsis to below 200 km (via one or more rounds of Aerobraking + retrograde thrusts) and then do a shallow reentry at ~40-50 km Periapsis.

No heatshield required (and I am even able to recover the last motor stage, by having it equipped with chutes and only separating it, when speed are below 260 m/s ).

And that´s with Deadly Rentry active (which is said to tweak the 1.0.4. rentry values to make rentry harder than with stock 1.0.4.)

[Warzouz]

Duna is a place you really need airbrakes. It's a matter of easy aero landing versus narrow (if not nonexistent) margin of not capturing and too low.

Well, my very recent experience (yesterday) says otherwise. Sure that depends on you ship design. But on Duna you can enter atmo with a non streamlined vehicle withour airbrakes. My entry wasn't even smooth. I deorbit for around 60m/s. The PE was in the ground. No airbrakes, no drogue only chutes open at 600m/s and deployed at 2500m, not the default 500m (The ship was designed in 1.0.2)

I even landed my Kerbin return vehicle on Duna (a XP bus for kerbals). 14 chutes, 2 hichhiker cans, MK2 command mod, rockamax fuel and Poodle. No airbrakes nor drogue. Went well too (except the ship was tall and nearly falled...).

[Sharpy]

BTW, what's the pressure to set chutes to, to deploy at reasonable altitude on Duna? I have pressed space accidentally, and now my lander will deploy the chutes as soon as the preset conditions are met, but I can still change the presets.

[archnem]

Thanks for all the replies! Good to know I haven't borked my install, and I'm actually happy that re-entry is tougher now. It just kind of amazed me that a 260km suborbital hop destroyed my craft and I was worried I'd installed too many mods or something.

[Warzouz]

BTW, what's the pressure to set chutes to, to deploy at reasonable altitude on Duna? I have pressed space accidentally, and now my lander will deploy the chutes as soon as the preset conditions are met, but I can still change the presets.

I don't know for Duna. For Kerbin, it's 0.4 for Drogue and 0.65 for chutes.

Can't you repack you chutes with an engineer ? If not, "save" is you friend.

[Sharpy]

Only after they have deployed, after an atmospheric landing (when they turned red in staging). Can't do a thing while they are light blue.

[Warzouz]

And the repack chute won't allow to redeploy them by staging (or it had been fixed for 1.0.x). you'll have to assign action group to them.

[Sharpy]

It's not such a big problem if the pressure and altitude are set right. Just rightclick-deploy each while still in orbit.

[Warzouz]

It's not such a big problem if the pressure and altitude are set right. Just rightclick-deploy each while still in orbit.

Hmm, I had bad experience with "rotating/moving context menus"

Sadly there is no real decent ship control interface. I hope that will be introduced on 1.1/Unity 5.

[FancyMouse]

Hmm, I had bad experience with "rotating/moving context menus"

Sadly there is no real decent ship control interface. I hope that will be introduced on 1.1/Unity 5.

I remember seeing a mod on ckan that unmove context menus... can't remember the name (not at computer) but it seems doing its job reasonably well.

[Sharpy]

Looking for this?

[Dr.LoveJoy]

One simple approach is to always survive (unless you use Life Support and have limited resources...) is to skirt the edge of the atmosphere.

I don't know what would need to happen for Kerbin to kill you with 52km periapsis; if you are within Kerbin orbit you can reduce to 48km and it will keep ejecting you through the other side until you're down to a safe speed. On Eve that's 85km. Aerocapture + landing didn't even use up any ablator with these parameters, although it took a good dozen orbits to finally enter the descent. I don't know about Duna, but I imagine 40km should be quite safe.

Seriously, since 1.0 I never really had any use of heatshields. I just stick to a very shallow periapsis and everything except the most aerodynamic shapes lands just fine (and I stick a pair of airbrakes on the latter, deployed in space they work wonders.)

I don't know why more people don't talk about how magical AirBrakes are for re-entry assistance, especially when you are trying to go reusable. They even give you Pitch and Yaw control in atmosphere.. you can ride your retrograde vector down on rails without RCS.

A full blossom of 8 airbrakes on an orange tank, with engine, 2% fuel, probe body, battery and safety chutes, from an orbital trajectory of 150k and an entry vector at 14k does very well. I even tried it with a service bay attached and the chutes inside the bay to make sure the chutes would not get destroyed. Even heavier, and yet still deployed the AirBrakes while in orbit, and they brought my speed down to below 250 m/s by 5k or so, From there, you just pop the chutes... done. Or, if you want to avoid the weight, land propulsively. I do this by adding one more small fuel tank and disabling it before launch, then re-enabling it on re-entry. FYI I am playing with FMRS for testing setups for this and my new career mode attempt and it is working very well.

But even without AirBrakes, if you set the deployment pressure at the right level, you can deploy the chutes in space, then wait until a bit before they will deploy and if you saved some fuel, burn off your velocity so the chutes don't get destroyed.Its trickier, but again.. possible to do if you test a few setups first.

Landing gear is another thing.. oof. I think I may try installing cubic octagonal struts to bring them down low enough. Until this point, I have been landing my orange tank stages in water because of this. I did add some linear RCS and tested it with that to prevent 'fall over destruction' as well as to give a bit more maneuverability during re-entry, but that seems a bit overkill, and adds too much weight.

My Next Step: Install vernier RCS engines and play with them to see if they are more efficient and controllable for re-entry retro burns than a MainSail. Using one large chute as well as AirBrakes, velocity can come way down, and you only need to cancel a small amount of Delta V to land safely.

[FancyMouse]

I don't know why more people don't talk about how magical AirBrakes are for re-entry assistance.

For me airbrake just seems too overpowered that I'm not going to be surprised if it's nerfed in some future version, so I'm only using it when absolutely necessarily, which doesn't include most of the Kerbin reentry.