Author Topic: FAILURE: IRNSS-1H, PSLV C39, SLP, August 31, 2017 (13:30 UTC)  (Read 61784 times)

Offline ZachS09

So sorry that PSLV did not get into the proper orbit today.

Hopefully, ISRO will find some way to ensure that the heat shield separates properly next time.
« Last Edit: 08/31/2017 04:11 PM by ZachS09 »
"Liftoff of Falcon 9: the world's first reflight of an orbital-class rocket."

Offline jcm

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The third stage was meant to get to the east Pacific off Chile. The underspeed means that won't happen - be
on the lookout for reentry reports in Borneo or New Guinea.
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Offline AJA

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The third stage was meant to get to the east Pacific off Chile. The underspeed means that won't happen - be
on the lookout for reentry reports in Borneo or New Guinea.

Has the fourth-stage+satellite combo been given a tracking number yet? Will it be visible? It's a fairly reflective (given that it's all white, and big) thing, no?

Offline jcm

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The third stage was meant to get to the east Pacific off Chile. The underspeed means that won't happen - be
on the lookout for reentry reports in Borneo or New Guinea.

Has the fourth-stage+satellite combo been given a tracking number yet? Will it be visible? It's a fairly reflective (given that it's all white, and big) thing, no?

Not yet, but it will be 42927  (2017-051A)
Remember it will low on the horizon for observers in temperate latitudes - apogee is 6500 km over the equator
but I'm too lazy right now to caclulate how far north that remains visible...
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Offline AJA

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The ISRO chairman announced on podium that due to heat shield seperation failure , mission unsuccessful on DD national tv.

That wasn't the ISRO Chairman. That was the RCO (Range Control Officer).
Acting as per the instructions of the ISRO Chairman of course.

Like Sea Launch.... if it fails, kill the webcast.

Deeply disheartening. Not that they'd be able to do live-troubleshooting - but they've taken off the links referring to this launch from the webpage. Including the links to the photo-gallery, and the launch brochure. No official press-release so far either(?)

Offline AJA

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The third stage was meant to get to the east Pacific off Chile. The underspeed means that won't happen - be
on the lookout for reentry reports in Borneo or New Guinea.

Has the fourth-stage+satellite combo been given a tracking number yet? Will it be visible? It's a fairly reflective (given that it's all white, and big) thing, no?

Not yet, but it will be 42927  (2017-051A)
Remember it will low on the horizon for observers in temperate latitudes - apogee is 6500 km over the equator
but I'm too lazy right now to caclulate how far north that remains visible...

I was asking for Indians, mostly, but will it be lit at that altitude?

Offline input~2

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Object A has been cataloged:

2017-051A/42928 in 166 x 6556 km x 19.16

Offline ZachS09

With a 167 km perigee, won't this fall from orbit fairly soon?

 - Ed Kyle

Eventually, the fourth stage & IRNSS 1H will decay from orbit. Don't know when exactly.
"Liftoff of Falcon 9: the world's first reflight of an orbital-class rocket."

Offline Star One

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FAILURE: IRNSS-1H, PSLV C39, SLP, August 31, 2017 (13:30 UTC)
« Reply #128 on: 08/31/2017 04:22 PM »
With a 167 km perigee, won't this fall from orbit fairly soon?

 - Ed Kyle

Eventually, the fourth stage & IRNSS 1H will decay from orbit. Don't know when exactly.

I'd of thought fairly rapidly in that orbit and being quite a large item.

Matter of days?
« Last Edit: 08/31/2017 04:22 PM by Star One »

Offline vineethgk

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This is definitely too early to say, but perhaps this *may* have been a relatively minor fault during manufacture or integration (or even the software) that escaped the QA. ISRO might even launch the under-construction IRNSS-1I as a quick replacement soon. But the fact that a mission to replace a failed satellite (IRNSS-1A) has itself was a LOM due to launch failure might likely result in the agency facing probing questions from Govt auditors.

Offline Lars-J

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It's a bit embarrassing that the announcer kept repeating that performance was normal/nominal even though we could see that the altitude and velocity graphs were diverging from their expected plots. It seemed like he was reading off a script rather than examining the data. And especially given that they should have known by that point (minutes before) that the fairing failed to separate.
« Last Edit: 08/31/2017 05:01 PM by Lars-J »

Offline eeergo

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With a 167 km perigee, won't this fall from orbit fairly soon?

 - Ed Kyle

Eventually, the fourth stage & IRNSS 1H will decay from orbit. Don't know when exactly.

I'd of thought fairly rapidly in that orbit and being quite a large item.

Matter of days?

The perigee is pretty low, but the ballistic coefficient should be quite low too (typical is ~150-200 cm^2/kg, but for this one I calculate it would be between 50-150 cm^2/kg, depending on ram being nose-first/minimal area or sideways/maximal area), owing to the large mass and good aerodynamics.


See the plot for illustration what a high perigee can do to orbital lifetime (source: Chobotov's "Orbital Mechanics" book). It can very well happen this stack will stay in orbit for weeks if not months.
« Last Edit: 08/31/2017 05:19 PM by eeergo »
-DaviD-

Offline eeergo

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It's a bit embarrassing that the announcer kept repeating that performance was normal/nominal even though we could see that the altitude and velocity graphs were diverging from their expected plots. It seemed like he was reading off a script rather than examining the data. And especially given that they should have known by that point (minutes before) that the fairing failed to separate.

To be fair, the "nominal performance" calls were for the engines, which did their job. Closed-loop guidance also appeared to have tried correcting for the extra weight. Of course, integrated LV performance was very off-nominal.
-DaviD-

Offline maint1234

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The ISRO chairman announced on podium that due to heat shield seperation failure , mission unsuccessful on DD national tv.

That wasn't the ISRO Chairman. That was the RCO (Range Control Officer).
Acting as per the instructions of the ISRO Chairman of course.


Definitely kiran kumar the chairman. He was the only speaker on the normal podium. Saw it on DD.

Offline input~2

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Quote
The failure is of the rocket and the satellite built by the private consortium remains untested, scientists said.
http://www.ndtv.com/india-news/indias-first-private-sector-built-satellite-launched-by-isro-from-sriharikota-1744575

Offline Mapperuo

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Launch broadcast up to cut off is on YT for those catching up

- Aaron

Offline jcm

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With a 167 km perigee, won't this fall from orbit fairly soon?

 - Ed Kyle

Eventually, the fourth stage & IRNSS 1H will decay from orbit. Don't know when exactly.

I'd of thought fairly rapidly in that orbit and being quite a large item.

Matter of days?

I would guess weeks to months
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Offline jcm

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Object A has been cataloged:

2017-051A/42928 in 166 x 6556 km x 19.16

Odd, I wonder what 42927 is being reserved for?
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Offline Ben the Space Brit

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Shouldn't there be an abort mode that can be remotely activated when MCC knows that it's a LOM so as to stop what is effectively space debris being thrown into a high orbit like this?
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Offline eeergo

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Crazy thought about re-entry I had:

-This is an unusual "spacecraft" in that it has ~half of its mass unsecured inside, with around 1/3rd of the stack envelope to move about. The aerodynamic moldline will tend to point it forward when drag is strong. This will also push 1H to the front, increasing this attitude's stability.

- Being encapsulated, 1H will have its 800 kg of propellants freeze pretty soon.

- No active control is possible whatsoever (S4 burned to depletion, sat dead soon)

- Depending on the fairing's failure mode, it could well be completely structurally intact (pyros not fired).

- Being designed for large heating and aerodynamic stresses, it will protect the stack for at least some part of the reentry if left as it is.

- Crazy part: how strong is this fairing? As far as I know it's aluminum, but has it been changed to carbon fiber? This would give it some strength to withstand some of the most stressful reentry phases. Presumably not all of it though (seams are metal and would give in, splitting it, for example). This would make a full-on "warhead-like" scenario implausible, I think.

- However, we've seen instances of other unprotected, frozen fully-fueled sats being recognized as potentially dangerous. This one will presumably be at least somewhat protected. Fairing failure will concievably happen along the separation seam first, and free the sat with little chance of big blows against the downstream structures.

Should somebody be worried about hydrazine snowballs reaching the surface? :\
-DaviD-

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