Copenhagen Suborbital - Pad Abort Test - Postponed till Sunday Aug 12

[IRobot]

Is it just me or are these guys neglecting the electronics and control part a bit? I guess their background is mechanics and chemistry and they want to stay focused on that, but is that enough?

[mrhuggy]

Nice work there Morten and the rest of the team.

Looking at the video the main problem the capsule didn't release on time as a result it rotated too much and ended up much lower and in the wrong postion. As a result the parachutes didn't have time to inflate.

[Morten C.]

Is it just me or are these guys neglecting the electronics and control part a bit? I guess their background is mechanics and chemistry and they want to stay focused on that, but is that enough?

They already work on active control. They have just not flown anything yet.

In the fall of 2011 they did some static test to find what material to use for jet vane rudders. They settle with copper vane, after first tried out graphite, that could not cope with the forces.

^{Photos: Thomas Pedersen/CS}

Flemming Nyboe/CS have been working on the software to the guidance system that consists off an IMU from Analog Devices and a ARM7-microprocessor.

This is what going to be the SAPPHIRE rocket. The plan was the fly it this year, but it might be next year, because last weekend was the last launch window and CS have been working hard on the missions they already had. But who knows if they get the energy and a new window to do it this year.

There is a few videos on their site, that show a servo test, and static test with and without highspeed

http://copenhagensuborbitals.com/sapphire.php

There is more photos their gallery

Regards
Morten

[Morten C.]

Nice work there Morten and the rest of the team.

Looking at the video the main problem the capsule didn't release on time as a result it rotated too much and ended up much lower and in the wrong postion. As a result the parachutes didn't have time to inflate.

You give me way to much credits. Not a part of CS myself, but I am a member of the support group CSS, so I pay for a little part of the fun 

Well as i understand the comments on Arocket, the stack got unstable as the propellant burn it change the CG and move after the CP, and that leads to the loop. Sure other can explain it much better then me.

That is one of the reason that the Apollo LES have a ballast of depleted uranium to move the CG forward.

Been trying to look for information about the Apollo LES, but don't think there is much out there.

Not sure if they separated the LES before the loop it would have gain enough altitude. At that point there 1.5 sec or so left of the burn, that was needed to get the rest of the altitude.

Maybe if they separated just before it it reach the apogee, there would have been altitude enough to get the main parachutes fully unfolded. But that is guessing

Regards
Morten

[Morten C.]

Looking at the video the main problem the capsule didn't release on time as a result it rotated too much and ended up much lower and in the wrong postion. As a result the parachutes didn't have time to inflate.

From article on Wired

DIY Space Capsule Test Launch Ends With Crushing Splash

As their launch escape system tumbled out of control, Copenhagen  Suborbitals didn’t want to remotely trigger the explosive bolts and  separate rocket from capsule. That could have unleashed an  out-of-control rocket toward their observation ships. Instead von  Bengtson waited until the engines had almost stopped burning, then  triggered the separation and the capsule’s parachutes.

[savuporo]

4. The system ended up tumbling. It was not surprising, but unfortunately ate too much of our parachute altitude.

I am surprised, but probably out of ignorance. It's not supposed to be passively stable ?

[Morten C.]

First thought from Kristian on Wired, and with new pictures

DIY Capsule & Launch Escape System Post Flight Evaluation

Sound like more data will be looked at this weekend

More pictures added to the CS gallery

Like this one showing TDS rebounds after splashdown

[Morten C.]

4. The system ended up tumbling. It was not surprising, but unfortunately ate too much of our parachute altitude.

I am surprised, but probably out of ignorance. It's not supposed to be passively stable ?

Not sure what you mean, but if you mean it could be inherited stable, than no.
It is a little counterintuitive, as one would guess that the weight of the capsule would keep the LES pointing up.

Have a look at The Pendulum Rocket Fallacy
http://en.wikipedia.org/wiki/Pendulum_rocket_fallacy or
http://web.archive.org/web/20091018232320/http://geocities.com/jim_bowery/pendrock.html

There is a reason to why rockets have the engine in the bottom and the mass on top.

Even passive stable rocket normally have fins and spin to even out the imperfection of the thrust

Regards
Morten