[Re-entry RSS/RO: random (?) explosions]

Hey guys,

I have to admit I'm quite new to RO and RSS.

I'm currently trying to reenter simple craft from LEO and having some troubles with it.

 

I tried PE'S around 55-80km (AP around 250km), but I always explode at the end of reentry. What troubles me is the fact,

that the craft explodes pretty late, after the reentry heat effects and ablator usage is down again. At this state most of the velocity reduction is already done.

I end up thinking it was a succesfull re-entry and the suddenly the craft explodes. Sometimes for heating and sometimes because of g-forces.

One time it happened at 12 kms altitude and 140 m/s velocity (I was just waiting for the parachute to open). The log said MK1 exploded because of g-forces, but how can that happen if the craft is traveling at 140m/s?

Actually agressive re-entrys with EP's of around 35-45 km seem to work better than softer ones around 70 km. Although I experience very high g-forces here (around 13g's), the craft doesn't explode.

 

As the craft itself is quite simple (just an MK1 pod with an MK16 parachute on top) I don't think the problems is a wrong design. MK1 description sais it has an integrated LEO-heatshield, and I activated "descent mode".

 

Is this some kind of a bug or am I missing something essential here?

(For my general understanding: reentering at lower EPs (and therefore steeper angles) will increases g-loads and maximum heating. Reentering at higher EPs (and therefore shallower angles) will reduce maximum temperatures and g-loads by extending the atmospheric breaking and bleeding off the orbital velocity slower.) 

[ARC - Rocket Science]

„Scientists unveiled: ancestors worked on Rocket Science”

Mr. President,

we, the Ancestors Research Committee (ARC), recently discovered a new branch of technology the ancestors have been working on. This so called “rocket science” used breaking edge technology to extend the ability of high speed, high altitude flights. Their goal was to extend ancestorkind to other celestial bodies. We don’t know about the outcome of this project, but as it seems, building big cities all over the place wasn’t the only thing the ancestors were capable of. In order to find out, what has happened to their society, we highly recommend funding a space program. For this and…for the BOOM!

The Ancestors Research Committee

 

So here we are, gazing at the stars. Equipped with some funds, a huge load of determination... and some crazy Kerbals willing to jump on everything that might be flammable. Rocket Science…that’s basically strapping good stuff on top of a huge pile of high explosives, hoping the good stuff won’t become scrap. How hard can that be?

 

This series is played in KSP 1.2.2 with RO, RSS, RP-0 (and a lot of other mods). With a bit over 100h of “vanilla” KSP it’s my first time of playing RO and RSS, so it might turn out to be quite a challenge. In fact, I expect many things to go BOOM, but that’s part of it isn’t it? To make this even more of a challenge and to keep things interesting I’ll follow a quite strict “no reloads/reverts” philosophy, especially regarding crewed missions. What is dead may never die, but also never live again (sorry fellas from the Iron Islands). I love all the other mission reports here and hope some of you will have some fun while following my progression!

Beginning with sound rockets. Let’s see which altitude we can achieve and collect some scientific data.

 

Spoiler

Slingshot I:

Standing proud on the piece of dirt the R&D guys call a launchpad: The Slingshot I!

This spin stabilized rocket is our first try to launch something entirely powered by jet propulsion. As Kerbalkind may have never reached altitudes as high as what might possible here we added some scientific payload to measure flight telemetry, temperature and barometric pressure.

At t-0 the engines ignite with an aggressive hiss and boost Slingshot I upwards at astonishing velocity.

Slingshot I shortly after lift-off.

Mission Control later confirms an altitude of more than 17km and an estimated velocity of Mach 1,2. The scientists from R&D immideatly jump to action, anaylzation of the recorded data has top priority.

Spoiler

Scorpion I:

After the impressive and successful launch of Slingshot I the collected scientific data was used to develop an impressive new rocket motor. The resulting upscaled rocket was called Scorpion I and promised setting new altitude and speeds records. As the R&D guys still hadn’t found out how to control an unmanned vehicle properly the Scorpion I was spin stabilized again. The payload remained the same but was upgraded with a prototype of a newly developed parachute, which gave a chance to actually bring back things in one piece from up there.

Scorpion I in flight.

Launch and ascent of the vehicle proceeded nominal and raised our uncrewed speed record up 1200m/s. This lead to a pretty rough ride up, as high velocities seem to induce great stress on structural parts of the vehicle. Thankfully our engineers used advanced materials and the vehicle successfully withstood all aerodynamic forces, setting a new altitude record of 108km.

False programming of the parachutes predeployment sequence lead to it getting destroyed at an altitude of 20km and a loss of the payload duo to high velocity impact.

Scientists cheered, as the data collected by Scorpion I confirmed, that it is indeed not possible to perform aerodynamic flights at high altitudes because of the decreasing atmospheric density.

Spoiler

BSR 1 (Biosample Return):

With the Scorpion Ia we’re witnessing the next milestone in kerban spaceflight: the first multi-stage launch vehicle. After being accelerated through the atmosphere by the first stage’s heavy rocket engine, the second stage is separated and then ignited. As someone from the engineering team stated: “dumping the scrap away seems like a good idea”.

Launch of the Scorpion Ia proceeded as planned and the first stage lifted the vehicle out of the dense parts of the atmosphere.

After separation the second stage ignition sequence failed. Duo to low feeding pressure mission control was not able to ignite the second stage engine, which left the upper stage on a parabolic trajectory. After reentry with high g-loads and slight heating, the parachute suspension snapped at an altitude of 25km. The complete loss of the high altitude biosamples was confirmed later.

Spoiler

BSR 2:

The problem with Scorpion Ia’s upper stage was quickly found by our clever engineers. Fuel tanks were switched out for pressurized ones which should deliver correct feeding pressure.

Mission BSR II was ready for launch!

After successful lift-off Scorpion Ia seems to work pretty well, but mission control soon registered a deviation from the planned trajectory. The vehicle was accelerating way to fast, but as everything else seemed to work, nobody wanted to hear concerns about “a rocket going to fast”. Separation proceeded as planned, yet again the second stages ignition failed. The payload was still able to reach a new altitude record of 368km. The requested biosamples were recovered after landing some kilometers away from the space center. The parachute worked this time.

BSR-2 biosamples returning home.

After analyzing flight telemetry, the cause of error was discovered soon. Apparently, someone forgot to load fuel into the seconds stages new tanks after they had been switched out. If the responsible subject is ever found, he/she might find himself at the top position of the “test pilots for ambitious projects” - list.

 

New episodes already done and will be uploaded when I find the time  

[The Space Program With No Name (updated Jan 12, 2019)]

Nice work @SBKerman, keep it up!

It's also always interesting to read about (partial) failures (like  SCAR-5). Can't count on how many times I blew things up in the last months