How to protect your parachutes?

[Loren Pechtel]

I'm quite new to the game, so far I've only gone suborbital.

I'm trying to do two contracts at once--a tourist mission and a parts test.  The parts test is leaving me with a lot of velocity (really now, why do they want me to test a solid booster at 200km up??) but still suborbital--and when I re-enter my chutes are burning off no matter how carefully I hold the tail into the fire.  Obviously I could skip the parts test (I was able to bring the same hardware down minus a couple of bits of science and a lot of velocity earlier) but if I can't survive from high suborbital velocity how will I ever survive from orbit?  Or is the problem that I'm carrying the ton of crew cabin?

 

Also, have I found a bug?  I accepted a pad-test parts contract for a Rockodyne separator--and I can't find any way to do it.  All the conditions are true but there's no test button and firing the decoupler doesn't fulfill it.  Yes, it's 2.5m rather than 1.5 but I can build a 2.5m "rocket" (not that it could actually move) that should work.

[fourfa]

Welcome to KSP!  

On solid rockets - you can adjust how much solid rocket fuel they get filled up with.  By default, they are full to the max.  But place one on your rocket in the VAB, right-click on it, and you can drag the Fuel slider back and forth to change the fuel load.  In fact, you can turn it down to zero and the part test contract will still complete when you fire the (empty) SRB stage.

That should help on your suborbital velocity some.  How to make your craft draggier is a longer topic - lots of people have this problem too.

On the separator contract - right-click on the part when you launch and go to the launch pad.  You should see a Run Part Test button (or something like it) there.

[Loren Pechtel]

8 minutes ago, fourfa said:

Welcome to KSP!  

On solid rockets - you can adjust how much solid rocket fuel they get filled up with.  By default, they are full to the max.  But place one on your rocket in the VAB, right-click on it, and you can drag the Fuel slider back and forth to change the fuel load.  In fact, you can turn it down to zero and the part test contract will still complete when you fire the (empty) SRB stage.

That should help on your suborbital velocity some.  How to make your craft draggier is a longer topic - lots of people have this problem too.

On the separator contract - right-click on the part when you launch and go to the launch pad.  You should see a Run Part Test button (or something like it) there.

That solves the part test contract but doesn't deal with the bigger problem of the chutes burning off.  Note that the problem is not from popping them too early, they are being physically burned off the capsule long before safe deployment speed.  I don't know if my capsule is draggy enough or not--I've reverted the flight when the chutes depart and haven't seen if it ever gets down to safe speed or not.  The ablator seems to be protecting the capsule itself but the airflow past it is still getting to them.

 

As for the separator--I've had that before.  It's not showing up in this case.

[PnDB]

Hate to answer a question with questions, but...

Can you describe your rocket for the SRB test?  What does your ascent profile look like (straight up to 200k and straight back down?  a near-orbital-but-not-quite arc?)  If you can get up to 200km in a graceful arc that puts your perapsis around 20-30km, you may reenter in a more friendly and less hot manner, losing sufficient speed in the upper atmosphere before you get too low and hot.

What does your separator "craft" look like?  Is it just the separator sitting on the pad?

[Snark]

 

3 hours ago, Loren Pechtel said:

The parts test is leaving me with a lot of velocity (really now, why do they want me to test a solid booster at 200km up??) but still suborbital--and when I re-enter my chutes are burning off no matter how carefully I hold the tail into the fire.  Obviously I could skip the parts test (I was able to bring the same hardware down minus a couple of bits of science and a lot of velocity earlier) but if I can't survive from high suborbital velocity how will I ever survive from orbit?  Or is the problem that I'm carrying the ton of crew cabin?

You should have no problem reentering from suborbital, with the right trajectory and ship design.  It would help if you could post a screenshot so we could see what it looks like.

A couple of things:

First, if you're having heating problems for suborbital flights:  what kind of trajectory are you using?  Straight up and down?  That can be problematic.  Try launching on a long, shallow trajectory so that you go way far downrange; that way, during reentry you travel a farther distance through the thin upper regions of the atmosphere, and can shed more velocity there before you get down into the charbroil zone.  Depending on the shape of your ship, you may also be able to leverage a trajectory like that to give body lift, which can seriously ease reentry if done right.

Second, regarding the parachutes burning off:  Where are you putting them?  Try moving them to where they're out of the airflow.  For example, the Mk1 command pod has nicely sloped sides.  If you're entering butt-first (i.e. with the command pod's pointy end pointing retrograde), put the chutes on the sloped sides of the command pod, not down on the cylindrical sides of the rest of the rocket.  That way, they're out of the airflow and won't get heated so much.

3 hours ago, Loren Pechtel said:

Also, have I found a bug?  I accepted a pad-test parts contract for a Rockodyne separator--and I can't find any way to do it.  All the conditions are true but there's no test button and firing the decoupler doesn't fulfill it.  Yes, it's 2.5m rather than 1.5 but I can build a 2.5m "rocket" (not that it could actually move) that should work.

Are you sure you have exactly the right part that you're supposed to be testing?  For "test <specific decoupler> on the launch pad," all you should need would be the decoupler attached to a command pod.  Launch, hit the stage button, you're done.  What exactly does it tell you to test (the exact words in the contract), and what exactly is the part that you're testing?

(I note that there's no such thing as "Rockodyne".  There's Kerbodyne, and there's Rockomax, those are two different things.)

Edited January 28, 2016 by Snark

[Loren Pechtel]

27 minutes ago, PnDB said:

Hate to answer a question with questions, but...

Can you describe your rocket for the SRB test?  What does your ascent profile look like (straight up to 200k and straight back down?  a near-orbital-but-not-quite arc?)  If you can get up to 200km in a graceful arc that puts your perapsis around 20-30km, you may reenter in a more friendly and less hot manner, losing sufficient speed in the upper atmosphere before you get too low and hot.

What does your separator "craft" look like?  Is it just the separator sitting on the pad?

Test problem:

Mk1-2 capsule

Decoupler

2.5m service bay

There are two test conditions, both with what look like green checks (I have some red-green issues, while I'm sure the checks aren't red I won't swear they are green):  Kerbin, Launch site.

However there is no Test button on the decoupler, just Decouple and Enable crossfeed.  I've done parts tests with non-flyable contraptions before, it's always worked.

 

Parachute problem:

No, I am tipping over.  IIRC I had several hundred m/s of horizontal velocity and topped out somewhere around 150km on my first run--successful.  The second time the horizontal was something under 2000 m/s and I was falling back from something over 200km.  I wasn't paying attention to perapsis as it was a suborbital flight anyway.  The last time I'm sure my horizontal velocity was less as I tried going straight up until my apoapsis was like 210km and then discarding the booster.  I then burnt the SRB pointing horizontally when I crossed the 200km point--it had over 900 m/s of delta-v.  The re-entry vehicle is slightly heavier as I threw a thermometer and barometer in the service bay and I had a Probodododyne OKTO on the nose as I didn't have a pilot on board.

[Loren Pechtel]

5 minutes ago, Snark said:

 

You should have no problem reentering from suborbital, with the right trajectory and ship design.  It would help if you could post a screenshot so we could see what it looks like.

A couple of things:

First, if you're having heating problems for suborbital flights:  what kind of trajectory are you using?  Straight up and down?  That can be problematic.  Try launching on a long, shallow trajectory so that you go way far downrange; that way, during reentry you travel a farther distance through the thin upper regions of the atmosphere, and can shed more velocity there before you get down into the charbroil zone.  Depending on the shape of your ship, you may also be able to leverage a trajectory like that to give body lift, which can seriously ease reentry if done right.

Second, regarding the parachutes burning off:  Where are you putting them?  Try moving them to where they're out of the airflow.  For example, the Mk1 command pod has nicely sloped sides.  If you're entering butt-first (i.e. with the command pod's pointy end pointing retrograde), put the chutes on the sloped sides of the command pod, not down on the cylindrical sides of the rest of the rocket.  That way, they're out of the airflow and won't get heated so much.

Are you sure you have exactly the right part that you're supposed to be testing?  For "test <specific decoupler> on the launch pad," all you should need would be the decoupler attached to a command pod.  Launch, hit the stage button, you're done.  What exactly does it tell you to test (the exact words in the contract), and what exactly is the part that you're testing?

(I note that there's no such thing as "Rockodyne".  There's Kerbodyne, and there's Rockomax, those are two different things.)

Maybe the fact that I'm going up past 200km for the parts test is the problem then--there's no way to be all that shallow that way unless I carry almost enough fuel for orbit.

I am putting the chutes as high on the capsule as I can.  I wouldn't expect them to survive on the sides where the ablator doesn't do any good.

And you're right--it's Rockomax.  I'm getting check marks on the contract parameters, it certainly acts like I've got the right stuff.

 

Contract:  Test Rockomax Brand Decoupler

The part I'm using is a Rockomax Brand Decoupler.

[Snark]

7 minutes ago, Loren Pechtel said:

However there is no Test button on the decoupler, just Decouple and Enable crossfeed.  I've done parts tests with non-flyable contraptions before, it's always worked.

Decoupler tests just require you to stage the decoupler.  If all your green check marks are checked, then staging it should work-- as long as you actually have the correct decoupler that matches what the contract is asking for.

Would be handy to see a screenshot of your SRB test ship-- I'm still having trouble picturing it from your description, are you saying you used the Mk1-2 command pod on it?  That's the big 3-kerbal capsule, and it's a beast, it's crazy stupid heavy (weighs FIVE TIMES what the Mk1 command pod does), so it's best avoided unless either 1. you have a strong reason to need it (like it's specified in a contract), or 2. it's part of a much bigger ship so the pod mass doesn't matter much.

If you can make it so your reentry vehicle is just a Mk1 pod trailing an (empty) SRB behind it, that should be easy with a shallow-arc trajectory:  enter nose-first and use your command pod's torque to keep the nose pointed 20-30 degrees above prograde.  This will generate lots of body lift and you should come in nice and easy.

6 minutes ago, Loren Pechtel said:

Maybe the fact that I'm going up past 200km for the parts test is the problem then--there's no way to be all that shallow that way unless I carry almost enough fuel for orbit.

Well, that's true.  But you could lob it up high and keep a bit of fuel in reserve to slow yourself on the way down, just before hitting atmosphere.

[GDJ]

Another way to protect the parachutes is to come down at a shallow angle and take more time to aerobrake. I've done this many times, but turn the auto assist off (T) and let the pod naturally centre itself (it will). As long as the pod keeps itself centered the parachute won't burn up.

Also with the auto assist off you can do a rotation of the entire pod, and it will use gyroscopic action to keep it centered. The rotation will slow down as the atmosphere gets thicker, but so far doing it this way I've had excellent success.

[SSgt Baloo]

1 hour ago, Snark said:

Try launching on a long, shallow trajectory so that you go way far downrange; that way, during reentry you travel a farther distance through the thin upper regions of the atmosphere, and can shed more velocity there before you get down into the charbroil zone.

"Charbroil zone". I like that. I've been calling it the "thermal thicket".

[Loren Pechtel]

10 hours ago, Snark said:

Decoupler tests just require you to stage the decoupler.  If all your green check marks are checked, then staging it should work-- as long as you actually have the correct decoupler that matches what the contract is asking for.

Would be handy to see a screenshot of your SRB test ship-- I'm still having trouble picturing it from your description, are you saying you used the Mk1-2 command pod on it?  That's the big 3-kerbal capsule, and it's a beast, it's crazy stupid heavy (weighs FIVE TIMES what the Mk1 command pod does), so it's best avoided unless either 1. you have a strong reason to need it (like it's specified in a contract), or 2. it's part of a much bigger ship so the pod mass doesn't matter much.

If you can make it so your reentry vehicle is just a Mk1 pod trailing an (empty) SRB behind it, that should be easy with a shallow-arc trajectory:  enter nose-first and use your command pod's torque to keep the nose pointed 20-30 degrees above prograde.  This will generate lots of body lift and you should come in nice and easy.

Well, that's true.  But you could lob it up high and keep a bit of fuel in reserve to slow yourself on the way down, just before hitting atmosphere.

I've never flown the Mk1-2 pod, only used it for the test.  I unlocked it thinking it would be a better way to haul tourists around but then saw that I have no way to possibly use it at present--I don't have the 2.5m heat shield.

As for the SRB--I've always jettisoned it after the test.  It doesn't have a shield, it's going to burn anyway.  The reentry vehicle is a probe body, pod, crew cabin (tourist mission), service bay with power and a couple of light experiments and shield.

For my next attempt I'm going to try to put the periapsis into the atmosphere rather than the lithosphere.

[Plusck]

200km suborbital trajectory for an SRB test?! That is a vicious contract. I hope it pays well because yes, your options are limited to:

a) making it part of a much bigger mission (Mun fly-by or something) and pointlessly lug an SRB high into a Mun-encounter-without-circularising burn or something like that;

b) expensively making it very nearly orbital so that you can recover your people in one still-moist piece;

c) slightly less expensively abandoning a probe to certain death.

[Loren Pechtel]

3 minutes ago, Plusck said:

200km suborbital trajectory for an SRB test?! That is a vicious contract. I hope it pays well because yes, your options are limited to:

a) making it part of a much bigger mission (Mun fly-by or something) and pointlessly lug an SRB high into a Mun-encounter-without-circularising burn or something like that;

b) expensively making it very nearly orbital so that you can recover your people in one still-moist piece;

c) slightly less expensively abandoning a probe to certain death.

Yeah, I didn't realize the re-entry problems it was going to cause.  I took my previous tourist rocket, added fuel and the SRB (and some science) and figured it would work.  As I envisioned it, cheap--it would only add fuel and the part itself to the launch.  It's not going to take that much more to make it nearly orbital.  I could do it with fuel alone if I was sure of the numbers.

[Snark]

25 minutes ago, Loren Pechtel said:

I've never flown the Mk1-2 pod, only used it for the test.  I unlocked it thinking it would be a better way to haul tourists around but then saw that I have no way to possibly use it at present--I don't have the 2.5m heat shield.

The Mk1-2 pod is the worst possible way to haul tourists around.  It masses nearly 1400 kg per kerbal.  The Mk1 crew cabin is barely a third of that-- meaning you only need 1/3 the rocket to loft it, and (lots of folks don't appreciate this) it's much more forgiving on reentry, too, since less mass = less kinetic energy = less heat to bleed off.

The ideal tourist vehicle is basically just a Mk1 command pod, with enough Mk1 cabins slung behind it to carry the desired number of kerbals.  (If you've got a probe core with SAS unlocked (like a HECS), you could dispense with the command pod and fly it pilotless.)  Put some steerable fins on the back end-- the AV-R8 winglet is great for this, it's unlocked fairly low in the tech tree.  This will make the craft nicely steerable while in atmosphere.

A craft like that can enter just fine from LKO without any heatshield at all:  it's light, draggy, and generates lots of body lift.  Just enter nose-first, keep it pointed 30 degrees or so above prograde, and body lift will be your friend.

If you're reentering really steeply, to the point where it's actually more punishing than return-from-orbit even though the velocity's a lot lower, then reentry heat could be an issue.  Options include:  1. stick a heat shield on the front end, with a nosecone on top to help with drag during takeoff (the nosecone can just burn off during reentry), and/or 2. have a little bit of fuel and a small rocket engine left over, which you can use for retro-thrust to slow to manageable speed before reentry.  Just a few hundred m/s of dV should be plenty.

32 minutes ago, Loren Pechtel said:

As for the SRB--I've always jettisoned it after the test.  It doesn't have a shield, it's going to burn anyway.

Except that with proper design, it can actually be helpful for slowing down, because it's large, light, draggy, and good for body lift.  You want your ship to resemble an empty soda can as closely as possible, in terms of shape and density, and an empty SRB is pretty good that way.

20 minutes ago, Plusck said:

200km suborbital trajectory for an SRB test?! That is a vicious contract.

Doesn't have to be.  Just empty it out.  An empty SRB doesn't weigh much, it's not even required to get up to orbital speed, and the shape + mass are ideal for optimizing body lift on reentry.

[FullMetalMachinist]

15 hours ago, Loren Pechtel said:

when I re-enter my chutes are burning off no matter how carefully I hold the tail into the fire.

Sorry if this has been mentioned and I missed it, but I have a question about this bit. Are the actual parachute parts exploding off of your ship, or is it just that the parachute icon in the staging list has turned red? I only ask because if you're using the mk 1 pod with 'chutes on the sides and reentering tail first, they really shouldn't blow up, especially if you have a heat shield. 

If that's not the case, and it's just the icons turning red, then your chutes are fine. Don't worry, you wouldn't be the first to be fooled by this. All the red icon means is that if you deploy them at that moment, they will be burned up. All you have to do is wait until drag slows your ship down enough for the icons to turn green. 

Hope this helps. 

[Loren Pechtel]

10 minutes ago, FullMetalMachinist said:

Sorry if this has been mentioned and I missed it, but I have a question about this bit. Are the actual parachute parts exploding off of your ship, or is it just that the parachute icon in the staging list has turned red? I only ask because if you're using the mk 1 pod with 'chutes on the sides and reentering tail first, they really shouldn't blow up, especially if you have a heat shield. 

If that's not the case, and it's just the icons turning red, then your chutes are fine. Don't worry, you wouldn't be the first to be fooled by this. All the red icon means is that if you deploy them at that moment, they will be burned up. All you have to do is wait until drag slows your ship down enough for the icons to turn green. 

Hope this helps. 

They are actually exploding.  I see the chutes stream (I did not deploy them) and then get the message about them being destroyed.  It even gets the one on the nose cone.

[Loren Pechtel]

34 minutes ago, Snark said:

The ideal tourist vehicle is basically just a Mk1 command pod, with enough Mk1 cabins slung behind it to carry the desired number of kerbals.  (If you've got a probe core with SAS unlocked (like a HECS), you could dispense with the command pod and fly it pilotless.)  Put some steerable fins on the back end-- the AV-R8 winglet is great for this, it's unlocked fairly low in the tech tree.  This will make the craft nicely steerable while in atmosphere.

A craft like that can enter just fine from LKO without any heatshield at all:  it's light, draggy, and generates lots of body lift.  Just enter nose-first, keep it pointed 30 degrees or so above prograde, and body lift will be your friend.

If you're reentering really steeply, to the point where it's actually more punishing than return-from-orbit even though the velocity's a lot lower, then reentry heat could be an issue.  Options include:  1. stick a heat shield on the front end, with a nosecone on top to help with drag during takeoff (the nosecone can just burn off during reentry), and/or 2. have a little bit of fuel and a small rocket engine left over, which you can use for retro-thrust to slow to manageable speed before reentry.  Just a few hundred m/s of dV should be plenty.

Except that with proper design, it can actually be helpful for slowing down, because it's large, light, draggy, and good for body lift.  You want your ship to resemble an empty soda can as closely as possible, in terms of shape and density, and an empty SRB is pretty good that way.

Doesn't have to be.  Just empty it out.  An empty SRB doesn't weigh much, it's not even required to get up to orbital speed, and the shape + mass are ideal for optimizing body lift on reentry.

Yeah, once I unlocked the Mk1-2 I saw that Mk1 + cabin(s) was lighter.  I don't understand the advantage of leaving the SRB on, though--more mass, same cross section.

[FullMetalMachinist]

7 minutes ago, Loren Pechtel said:

They are actually exploding.  I see the chutes stream (I did not deploy them) and then get the message about them being destroyed.  It even gets the one on the nose cone.

I hate to come off as dense or annoying by saying this, but are you sure that you don't stage them by accident while you're above the atmosphere? The only reason I ask is because of that bit that I put in bold. What exactly is the message that you get when they're destroyed? Something along the lines of "parachute was destroyed due to heating and atmospheric forces"? If so, then they were staged at some point, and deployed automatically when they got to the set atmospheric pressure. You change this to a higher number (which means lower altitude) while in flight or in the editor by using the right click menu. 

If that's not the case, and the actual parachute base part (the one that you attach to the ship in the editor) is exploding (with the noise and the fire and the Oh The Humanity) then that's a trickier problem. One that will be easier to track down if we could see a screenshot of your ship, preferably a few. One in the editor, and one or two during reentry that shows how you're coming in, and maybe one in the map view at the start of reentry so we can see what you're flight profile is. 

[Plusck]

45 minutes ago, FullMetalMachinist said:

I hate to come off as dense or annoying by saying this, but are you sure that you don't stage them by accident while you're above the atmosphere? The only reason I ask is because of that bit that I put in bold. What exactly is the message that you get when they're destroyed? Something along the lines of "parachute was destroyed due to heating and atmospheric forces"? If so, then they were staged at some point, and deployed automatically when they got to the set atmospheric pressure.

I quite agree. It's embarrassing having to ask but that "streaming" and "message about them being destroyed" does sound very much like they have been staged.

The parachutes should not be cyan at any time. If they are cyan, they have been staged. If you get a message that they have been destroyed then (AFAIK) they have been staged. If they are cyan, right-click them and disarm them, then rearrange their icons into a new unstaged stage so that you can release them later.

If you hear an explosion and see fireworks and you shake all over the place and suddenly you don't have any parachutes, then it is indeed an overheating problem. But it doesn't sound like this is what is happening. Instead, it sounds like a staging problem.

Edited January 28, 2016 by Plusck

[Loren Pechtel]

5 minutes ago, Plusck said:

I quite agree. It's embarrassing having to ask but that "streaming" and "message about them being destroyed" does sound very much like they have been staged.

The parachutes should not be cyan at any time. If they are cyan, they have been staged. If you get a message that they have been destroyed then (AFAIK) they have been staged. If they are cyan, right-click them and disarm them, then rearrange their icons into a new unstaged stage so that you can release them later.

If you hear an explosion and see fireworks and you shake all over the place and suddenly you don't have any parachutes, then it is indeed an overheating problem. But it doesn't sound like this is what is happening. Instead, it sounds like a staging problem.

I wouldn't have accidentally staged them repeatedly.  I don't think I had my headset on when I was doing this so I wouldn't have heard an explosion but it certainly seemed to me like the housing burned away releasing the chutes which were of course promptly destroyed.

[Plusck]

OK. Well, the only things that I've had explode recently has been batteries mounted too close to the heatshield, so my memory of what happens to parachutes is hazy. I seem to remember being trapped in a nose-down configuration not too long ago, and when the parachute exploded there was simply nothing left of it. I don't recall the housing being destroyed but just the whole parachute part exploding and leaving the top of the pod bare.

However, if you're holding your "tail to the fire", there really should be no way that a top-mounted parachute heats enough to be destroyed. Radial-mounted ones perhaps, but not the top.

So it gets even more embarassing to have to repeat myself because I don't want to be a pain, but I'm still finding it hard to believe that this is what is happening. Could you upload a pic?

[Snark]

1 hour ago, Loren Pechtel said:

I don't understand the advantage of leaving the SRB on, though--more mass, same cross section.

It's because an empty SRB is such low density that it's only a little more mass, and it's a lot more cross-section.

"What the dickens do you mean, 'more cross-section'?" I hear you cry.  "It's still just 1.25m diameter, right?"

Here's where we come back to the mantra I've been chanting all along: body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, body lift, ...

There are basically two ways to reenter atmosphere to avoid burning up:  Heatshield-style, and spaceplane-style.

A heatshield-style entry relies on drag only.  It follows the premise that the heat is really going to be terrible, and anything other than a heatshield is going to overheat and explode if it touches airflow.  So the entire ship needs to be as radially compact as possible, so that it can huddle safely behind the heatshield.  When reentering, you need to stick as perfectly retrograde (or prograde, depending on where you have the heatshield mounted) as possible, to keep that precious heatshield between your dainty bits and a raging blowtorch.

A spaceplane-style entry relies on both drag and lift.  It assumes that heat is tolerable (if uncomfortable) for non-heatshield parts.  It's based on the premise that you only get fried if you're going super-fast when you're down low where the air is dense.  So you rely on lift as much as possible so that your altitude drops only very slowly, so you have plenty of time to decelerate to tolerable speeds before you get down in the thick stuff.  You have no heat shield.  What you do is, you enter nose-first, and keep yourself pointed 20-30 degrees above prograde.  This generates lots of lift and keeps you up high while you bleed off speed.

And the important thing to remember is, you don't have to have a spaceplane to do a spaceplane-style reentry.  Any long, cylindrical ship will generate plenty of lift if you keep it angled well above prograde.  Not as much as it would if it had wings, but it's still quite a bit.  This is "body lift" and it is your friend.

Since you're entering at an angle, not directly prograde, the airflow is hitting the side of your ship, which means that adding that big, light empty SRB is giving you more lift surface to work with.  It's a net advantage to keep it if the SRB is less dense, on average, than the rest of your ship.  Whether it's less dense or not depends on the makeup of your ship.  An empty Hammer, for example, has a mass of 0.75 tons, which makes it less dense than a Mk1 command pod but more dense than a Mk1 crew cabin.  So if your reentering ship has any heavy components on it (like a liquid-fuel engine, or a full fuel tank), it's likely to be a net positive, but if you've been really rigorous at keeping the mass down and it's basically just a command pod with crew cabins, then it may be a negative.  Depends on the ship design.

Anyway:  Heatshield-style reentry becomes de rigeur at very high speeds, e.g. if you're coming back from an interplanetary mission at 4 km/s or more, you pretty much have to have a heatshield.  If you're coming back from Mun or Minmus, your velocity's around 3 km/s, and it's kinda borderline-- you can get away without a heatshield, but you're skating fairly close to the edge and need to be careful (i.e. don't set Pe too low, make sure your ship is very light and draggy).  For LKO speeds, however (i.e. under 2500 m/s), you can do just fine without a heatshield, if you do an effective spaceplane-style reentry.

For example, my standard reentry vehicle for "rescue a kerbal from LKO" is basically a Mk1 command pod, a mostly-empty 2-ton LFO tank, and a Terrier.  I enter butt-first with the Terrier but keep the ship angled to maximize body lift.  It does just fine without a heatshield.  Slows down wonderfully.  I can often get down to 10 km and then actually climb a kilometer or two before it runs out of steam and falls again.

[fourfa]

"The housing burned away releasing the chutes" is not a thing I've ever seen happen, though it does sounds exactly like what happens when you accidentally stage the parachutes in space before re-entry.  We believe you are not doing it intentionally - KSP has a problem that makes this happen all too often.

If you go to outer space and stage your chutes, absolutely nothing happens (yet).  The chutes stay in their containers, and there is no visible change.  But once you enter the atmosphere with staged chutes, a couple things happen eventually.  The chutes have two tweakable bars if you right click on them: one for the atmospheric pressure at which it will initially deploy (partial deploy - dragging behind you but not fully extended), and the second for the altitude above ground at which it will fully deploy and slow you down all the way (1000m by default).  The default setting on the second is usually fine.

The first - partial deploy - by default is set to 0.05atm, which is in the very very high atmosphere where the chutes are still useless, and if deployed there, will invariably be destroyed along with a notice like "your parachute was destroyed by atmospheric forces and heat."  If you change that partial deploy tweakable before re-entry to 0.50 (well into the lower atmosphere, by which time ships will often have slowed down to the safe 250m/s deploy speed), you can safely stage your parachutes in space, and they'll just pop out automatically at a safe time. 

What's KSP's problem?  Well, its default behavior in the VAB is to stick the parachute staging on the same stage as your final ship engines and decouplers.  This whole thing sounds precisely like you made a ship that goes to space (200km part test), and when you added the chutes in the VAB, they were automatically added to the same staging event as your part test.  Unbeknownst to you, they "staged" or entered a armed, ready-to-deploy state.  Nothing changed externally, and you didn't notice the sound of the chutes staging because it happened at the same time as a decoupler and engine activation.  Then when re-entering at terrifying speed, the chute dumbly obeyed its default deploy threshold of 0.05atm, threw the chute out, and was destroyed.

Three ways to check or change it (forgive me if it sounds like I'm talking down here).  One - the staging of the parachute (the chute icon on the right side of the screen in the VAB, or the left side in flight) should be on its own numbered stage, with nothing else with it.  You might not yet have discovered that you can drag these icons around in flight (as well as in the VAB), re-order them, move whole stages up and down - give it a try.  Second, you can right-click the chute in space and change it to 0.50 and see what happens.  Third, since the recent 1.0.5 update, when you right-click on chutes that have been accidentally deployed, there will be a button called "disarm chute" - that will un-stage it and make it ready to deploy again at the appropriate time.  Squad added this because the situation you're describing happens a LOT.  Let us know how it goes.

Edited January 28, 2016 by fourfa

[Loren Pechtel]

5 minutes ago, fourfa said:

"The housing burned away releasing the chutes" is not a thing I've ever seen happen, though it does sounds exactly like what happens when you accidentally stage the parachutes in space before re-entry.  We believe you are not doing it intentionally - KSP has a problem that makes this happen all too often.

If you go to outer space and stage your chutes, absolutely nothing happens (yet).  The chutes stay in their containers, and there is no visible change.  But once you enter the atmosphere with staged chutes, a couple things happen eventually.  The chutes have two tweakable bars if you right click on them: one for the atmospheric pressure at which it will initially deploy (partial deploy - dragging behind you but not fully extended), and the second for the altitude above ground at which it will fully deploy and slow you down all the way (1000m by default).  The default setting on the second is usually fine.

The first - partial deploy - by default is set to 0.05atm, which is in the very very high atmosphere where the chutes are still useless, and if deployed there, will invariably be destroyed along with a notice like "your parachute was destroyed by atmospheric forces and heat."  If you change that partial deploy tweakable before re-entry to 0.50 (well into the lower atmosphere, by which time ships will often have slowed down to the safe 250m/s deploy speed), you can safely stage your parachutes in space, and they'll just pop out automatically at a safe time. 

What's KSP's problem?  Well, its default behavior in the VAB is to stick the parachute staging on the same stage as your final ship engines and decouplers.  This whole thing sounds precisely like you made a ship that goes to space (200km part test), and when you added the chutes in the VAB, they were automatically added to the same staging event as your part test.  Unbeknownst to you, they "staged" or entered a armed, ready-to-deploy state.  Nothing changed externally, and you didn't notice the sound of the chutes staging because it happened at the same time as a decoupler and engine activation.  Then when re-entering at terrifying speed, the chute dumbly obeyed its default deploy threshold of 0.05atm, threw the chute out, and was destroyed.

Two ways to check or change it.  One - the staging of the parachute (the chute icon on the right side of the screen in the VAB, or the left side in flight) should be on its own numbered stage, with nothing else with it.  You might not yet have discovered that you can drag these icons around in flight (as well as in the VAB), re-order them, move whole stages up and down - give it a try.  Second, you can right-click the chute in space and change it to 0.50 and see what happens.  Let us know how it goes.

Now, that makes sense!  I've been fighting it about where it put the parachutes in the stacking on that design ever since I deleted a cabin from it.  They aren't stacked with the SRB but I could believe something has gone wrong and it's completely consistent with what I have been seeing.

[fourfa]

Funny, I updated a third thing while you must have been reading.  Last thing is if you're really REALLY not pre-deploying the chutes, then you're just going too fast when they deploy.  Anything over 250m/s and they'll rip off with the canned "destroyed by aero forces and heat" notification.  Not being able to slow down below 250m/s before hitting the ground - that's also pretty common particularly with suborbital flights.  Early career players tend to launch those straight up, re-enter straight down hoping to land back at the KSC, and never realize that a long arcing trajectory is crucial to re-entering safely.  That long arc is what gives you enough time experiencing atmospheric braking to slow down enough.  I've done the same thing myself many times.

Edited January 28, 2016 by fourfa