Jump to content

decelerating breaking rockets?


Pawelk198604
 Share

Recommended Posts

[quote name='Pawelk198604']I wonders does we have some rocket breakers, i mean something like Soyuz rockets breakers before landing, so we can decelerate before deploying parachute.[/QUOTE]

Seperatrons mate. stage them before you hit the ground. There is no way to automate this with stock though.
Link to comment
Share on other sites

I'm pretty sure Scott Manley has done this in one of his older videos.

[COLOR=silver][SIZE=1]- - - Updated - - -[/SIZE][/COLOR]

here it is - as a launch escape system [URL]https://www.youtube.com/watch?v=-89LENUwvxo[/URL]
(actual landing at around 4:40) Edited by obsidian_x
Fixed url
Link to comment
Share on other sites

Sepratrons are certainly useful, but I do wish that there were some inline versions of the same. Some little light structural rockets would be ideal, like ones that thrust laterally so you can push the nose of boosters away from the ship, and ones that thrust in parallel with their axis so you can (for example) eject a heatshield and trigger breaking rockets at the same time before deploying chutes.

The external ones have flexibility, sure, but with the atmospheric and heating overhauls recently, some that can be neatly "tucked-in" to the ship's fuselage would be welcome.
Link to comment
Share on other sites

[quote name='Fearless Son']Sepratrons are certainly useful, but I do wish that there were some inline versions of the same. Some little light structural rockets would be ideal, like ones that thrust laterally so you can push the nose of boosters away from the ship, and ones that thrust in parallel with their axis so you can (for example) eject a heatshield and trigger breaking rockets at the same time before deploying chutes.

The external ones have flexibility, sure, but with the atmospheric and heating overhauls recently, some that can be neatly "tucked-in" to the ship's fuselage would be welcome.[/QUOTE]

Might give [URL="http://forum.kerbalspaceprogram.com/threads/37138-0-24-2-Wolf-Aerospace-Perfectrons-L-E-S-Pack-11-08-2014"]Perfectrons [/URL]a try. It hasn't been updated in a while, but seeing as how it's just a part (And workd in 1.0.4 last I checked) it might be worth looking into.
Link to comment
Share on other sites

I find sticking some Puff engines on does the job (I always overbudget on the RCS fuel anyway). Three Kerbal command pod, hitchhiker, service bay and heat shield coming straight in from Minmus with a Pe in the 25-29km range give a nice controllable braking burn . Very handy if you suddenly realise you're heading for lumpy terrain......
Link to comment
Share on other sites

It's a neat idea but I don't ever bother. It would be neat if there were a stock part that was a laser altimeter and you could trigger action groups when the altimeter reads certain altitudes. So set up a bunch of Sepatrons on a heavy return vehicle to fire when the altimeter reads 10 m say.
Link to comment
Share on other sites

Don't forget, most command vehicles also have built in mono. I suspect it would be an insufficient amount to provide proper breaking, or just enough Puff engines to create enough instant impulse. Either way, it would be easy enough to supplement assuming the pod's reserves are insufficient.

I'm thinking a Mk1-2 Command vehicle with a large SAS module bolted under it and four Stratus Roundified tanks clipped into it. You could nestle at least eight puffs in there as well for the impulse. Add an XL Stack separator under the Large SAS and an Ablator beneath that-- Instant soft landing capability without chutes. If you wanted to be tricky, throw up some airbrakes onto the capsule. They're pretty good about surviving reentry deployed in my experience and I can fit at least three before things get horribly crowded.

Separate capsule, deploy airbrakes, reenter atmo, jettison shield, enjoy a brisk decent and begin counterburn at 500m to get a feel for the performance. I suspect you can probably wait until 200m safely, but am really guessing at this point. And maybe pack a chute and some sepratrons, because I'm at work and have no way to verify this beyond rough experience :D
Link to comment
Share on other sites

Hnn. Or a Rockomax separator (arrow pointed down) bolted to the bottom of a Mk1-2 with Sepratrons clipped in and an ablator below that. 4 of them can pull a Mk1-2 away from about 400ms. Probably more weight efficient, too.

A roundified tank is about .3 mass (full). x4=1.2 mass
A Puff engine is .09 mass.
Large reaction wheel .2 mass. x1

vs

Rockomax Decouple, .4 mass.
Separatron .01 mass.

Even if you added a silly amount of them (You could clip at least 16 to the inside if you really wanted to) you'd still come out way ahead on weight, but like somebody mentioned, your timing better be good. Still, it's not that impossible. A Mk1-2 can survive a 45ms impact and you only need to bleed about 150ms (ish) off by the time it gets that far into Kerbin.

Time the deceleration rate and the number or rockets needed to bring you to zero and you should be golden for most landings inside an altitude of 50-100m. I'm betting it would only take 4-6 by the time you're close to ASL. I'll test tonight. Could be fun. :D Edited by Ozzallos
Link to comment
Share on other sites

Works! 12 Sepratrons and struts of steel. :D

[img]https://www.dropbox.com/s/kvb8t4yoetkeapt/screenshot43.png?raw=1[/img]

Pretty much works as advertised. I used the Rockomax to clip the Seperatrons in and hung the heat shield off of it, so it pulls double duty. Face the seperator the right way (note the arrow) and you blow off the ablator once it's usefulness has expired, exposing your final deceleration stage. I call clipping fair in this case because the separator is preserved after use and nominally empty space. 12 Seperatrons are what it took to bring a minimally equipped Mk1-2 capsule from 150ms to zero, and trust me when I say your timing has to be dead on. You've got a four second burn window to do it and about the only advice I can give is you need to be seeing texture on the ground before you pull the trigger--the splotchy stuff before actual grass blades. Even if you pull it off successfully, anything on the outside of your capsule is likely to get trashed.

I'm going to say this is landing on hardmode without some sort of radar altimeter to trigger the burn. Unless you land in the same spot at the same altitude, terrain will vary and so will the textures that you use for terminal reference. As a final note, the Rockomax screws up the flight characteristics of the pod. Landings were handled with SAS set to retrograde. All in all, it kinda reminds me of the old cowboy days of Kerbal without a lot of the flight assist, so kinda fun... And potentially a bad way to end a mission.

Good luck :D

*the three outer seperatrons were part of the escape system, not the deceleration stage
**Designated craft name Mk1-2 (H)ard (L)anding Edited by Ozzallos
Link to comment
Share on other sites

And finally, I tested a Mono/Puff deceleration scheme... That more or less fails to perform. The Mk1-2 pod doesn't have nearly enough mono and supplementing it with more increases your rate of descent. In fact, weight becomes problematic with four more mono tanks and eight nozzles; the minimum required to make create timely deceleration. In this configuration you'll find yourself with a 250ms descent- 100ms more than the seperatron config -and only enough fuel to decelerate into the 80ms range... Well outside your capsule's ability to survive. Adding more fuel or nozzles to compensate adds more weight... See where I'm going with this? You might was well build a full up landing stage at this point. Or just use parachutes.

So in the end--
Seperatron Braking: Viable, but insanely risky.
Mono Braking: Completely inefficient.
Parachutes: Unless you're an adrenaline junky, use these.
Link to comment
Share on other sites

I have decelerated a landing pod from LKO with just airbrakes and sepatrons. It was fun :)
Fast forward to about 10:00 minutes for a successful manned landing.

[video=youtube;tDgtFswpFaI]https://www.youtube.com/watch?v=tDgtFswpFaI[/video] Edited by ShadowZone
Link to comment
Share on other sites

[quote name='Ozzallos']
Pretty much works as advertised. I used the Rockomax to clip the Seperatrons in and hung the heat shield off of it, so it pulls double duty. Face the seperator the right way (note the arrow) and you blow off the ablator once it's usefulness has expired, exposing your final deceleration stage. I call clipping fair in this case because the separator is preserved after use and nominally empty space. 12 Seperatrons are what it took to bring a minimally equipped Mk1-2 capsule from 150ms to zero, and trust me when I say your timing has to be dead on. You've got a four second burn window to do it and about the only advice I can give is you need to be seeing texture on the ground before you pull the trigger--the splotchy stuff before actual grass blades. Even if you pull it off successfully, anything on the outside of your capsule is likely to get trashed.

I'm going to say this is landing on hardmode without some sort of radar altimeter to trigger the burn. Unless you land in the same spot at the same altitude, terrain will vary and so will the textures that you use for terminal reference. As a final note, the Rockomax screws up the flight characteristics of the pod. Landings were handled with SAS set to retrograde. All in all, it kinda reminds me of the old cowboy days of Kerbal without a lot of the flight assist, so kinda fun... And potentially a bad way to end a mission.
[/QUOTE]

Don't all pods with control have the radar altimeter measurement available in IVA mode? If the margin is 4 seconds, surely the readout from that meter has to be sufficient.

Furthermore, mod-wise, I think Kerbal Engineer Redux provides a ground altitude readout if you plop in the engineering module (or have an engineer onboard) so this could also be used if landing from IVA without a parachute is too much to stomach :)

First post by the way, hello dear forum-goers.
Link to comment
Share on other sites

[quote name='SchweinAero']See title.

Has someone made a tool to calculate burn start height based on vessel mass, thrust and aerodynamics? If the air drag equations are available as KSP models them, it wouldn't seem very hard.[/QUOTE]

check in the kOS thread
Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...