Iran's Fajr satellite has decayed mysteriously

[xenomorph555]

The Fajr satellite that was launched on the 2nd of February has mysteriously re-entered today. It was launched to a 420km orbit and had a thruster to keep it in orbit for 18 months. But for some reason it has lost altitude every day and is now gone. It could be solar winds but all other satellites are fine, odd. I don't know how or why this has happened.

[Sampa]

I would say that the answer is either aliens or malfunctioning thrusters.

[vger]

Maybe somebody hacked it as a thank you for that recon drone incident a year or so back.

[xenomorph555]

I would say that the answer is either aliens or malfunctioning thrusters.

Confirmed, thrusters were firing the wrong way *FACEPALM* sigh well hopefully they will get it right on Fajr-2, they have only had to rebuild it 3 times...

[Sampa]

Confirmed, thrusters were firing the wrong way *FACEPALM* sigh well hopefully they will get it right on Fajr-2, they have only had to rebuild it 3 times...

Yeah, the aliens thing was more of a joke

[xenomorph555]

Yeah, the aliens thing was more of a joke

Yeah I know, the Iranians designed this one weird (it was built by university students after all) it has 2 thrusters, one to decay and one to raise the orbit. The flight computer kept firing the decay engine.

[moronwrocket]

No, they just forgot to hit the "control from here" button with the probe core. Like we've never done that...*whistles*

[Aethon]

Floating point errors. Probably clipped parts. I blame the new offset tool.

[xenomorph555]

In all seriousness though I'm sorry if I have offended any Iranians here with my sarcastic/satirical nature, this was likely an expensive failure for you guys and probably a cra**y day anyway with stuff going on over in the East. I'm sorry this happened but keep on going I guess and eventually you can be on par with South Korea (they make good sat's, r8 8/8 m8)

[magnemoe]

Confirmed, thrusters were firing the wrong way *FACEPALM* sigh well hopefully they will get it right on Fajr-2, they have only had to rebuild it 3 times...

The wrong way, this sound weird I assumed they checked the orbit after each burn and if the orbit was lower something would be wrong.

This is an typical issue in KSP if you control from bottom docking port, however this is not an major problem for correction burn except the lost fuel, only the long ones where you wanted to go to Mun but deorbit instead.

yes I know its harder to get orbital information i real world than in KSP but still.

[-Velocity-]

Well, at least they didn't blame it on US radar emissions.

[Neil1993]

From the engineering projects I've done, these kinds of "getting it backwards" issues usually result from a lack of proper quality control and documentation. This can be caused by either a general lack of experience or, more likely, a very rushed schedule. I recently saw my friends' fire-fighting quad-copter attempt to fly upside-down because they installed the gyro the wrong way up and this was for a university project where they were most definitely pressed for time.

[tg626]

My grandfather was part of the Talos missiles project. First prototype flew off the launcher and promptly turned nose down into the ocean. Seems they installed the pitch gyro in place of the yaw gyro and vice versa.

After that they changed the connectors so they couldn't be interchanged.

;-)

[Neil1993]

My grandfather was part of the Talos missiles project. First prototype flew off the launcher and promptly turned nose down into the ocean. Seems they installed the pitch gyro in place of the yaw gyro and vice versa.

After that they changed the connectors so they couldn't be interchanged.

;-)

Wasn't there a Russian Proton rocket that had a similar issue about a year ago...? XD

[SubzeroSpartan7]

Wasn't there a Russian Proton rocket that had a similar issue about a year ago...? XD

Yep, the sensor that detected vertical movement (I do not the specific name it escapes my mind) was installed upside down. So yeah the rocket swiftly did a nose dive into the ground.

[Nibb31]

It reminds of the Energia-Polyus launch.

The 80-ton top-secret military satellite was supposed to do a 180 degree rotation to perform the circularization burn, but due to a silly programming error, it did full 360 degree rotation and promptly deorbited itself. Oops.

Edited February 28, 2015 by Nibb31

[Sampa]

Wasn't there a soviet satellite that they intended to deorbit, bu it instead put itself on a higher one?

[xenomorph555]

Wasn't there a soviet satellite that they intended to deorbit, bu it instead put itself on a higher one?

First Vostok test.

[Tommygun]

Didn't one of the missiles used during the Johnston Atoll tests detonate over the wrong island when they switch the launching and targeting islands and then forgot to reprogram the missle?

[SOHEIL]

[vger]

Well, at least they didn't blame it on US radar emissions.

...yet.

[Flixxbeatz]

I found the problem: It was launched in a 420km orbit. Maybe it wasn't launched high enough...

[Sirrobert]

This thread is just one big list of Schadenfreude

[magnemoe]

This thread is just one big list of Schadenfreude

Second page is mostly similar experiences. And yes I have done the same in KSP, however my point stand, had this been the final circulating burn by the satellite after it upper stage separation it would be very understandable. However not understanding that is wrong then the satellite orbit become lower then they do an orbit raising burns over a week sounds more like an organization issue than quality control. Don't they have an copy on ground? I thought that was pretty standard for non standard satellites and probes?

[xenomorph555]

Okay, I have learnt that the issue was not due to the thruster firing the wrong way, if fact the thruster was never fired for some reason (one theory is thermodynamics breaking pipes). This leaves the important question of how it decayed in less the a month when the previous satellite Navid lasted 2 months at the same altitude. My guess is solar winds.