Author Topic: Orbital's Antares Discussion Thread (to Hotfire Test and debut flight)  (Read 35190 times)

Offline Antares

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I thought the major space news outlets (NSF and SN) have indicated that the pacer for this vehicle has been the launch site.  Engine integration is a challenge for a company that has always launched solids (and builds neither the stage nor the engine itself), but it wasn't the source of delays, AIUI.
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Offline Jason1701

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Why is the pad called 0A?

Offline russianhalo117

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Why is the pad called 0A?
Before MARS was created and these pads were "civilianized" it was known as LC-0 and SLC-0.  SLC-0 has two active pads 0A and 0B. 0C and 0D were not used or built (that needs some verification since I'm running off my own memory).

Offline Skyrocket

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Why is the pad called 0A?

The launch pads at Wallops were numbered Launch Area (LA) 1 to 5 from south to north. When the new launch pad for Conestoga was added in the 1990ies south of LA-1, it was called LA-0A. Then a second commercial pad was added as LA-0B.

Offline Joffan

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Great news on the successful hotfire. Based on that performance and my gut feeling, my predictions for the next steps are:

COTS 1 (demo launch): April 2013
COTS 2/3 (demo resupply): August 2013
CRS 1: Dec 2013-Jan 2014

I stand ready to be impressed if Orbital beat these dates, disappointed if they slip past them, and smug if they hit them all. :)
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Offline R7

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Sorry if a faq but was this the first time these particular NK-33 AJ-26 engines have been fired?
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Online ugordan

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All the engines were acceptance-fired first, AIUI. However, this may well be the first time an NK-33 engine was fired simultaneously with another one.

Offline antonioe

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This has been bugging me for a while:

Can someone tell me what the "7K" in "7K hot fire test" stands for?

It's short for "7000", which is just a milestone number in someone's Gantt chart somewhere.

IIRC, it comes from the traditional Yushnoye/Yushmash nomenclature for their rocket cores: flight units have serial numbers starting with "1000" (many other companies, e.g. car and GA aircraft do something similar.... avoid "low" ser nos.) then static test articles have serial numbers starting with "5000" to make room for a lot of flight units (I guess if they build more than 3,999 thats a great problem to have.)

Then static fire units are "7000" units... can't remember if "6000's" are dynamic tests or pressure tests units...

Hence the "5K" and "7K" tests...

I may have the details wrong... any of our Ukrainian friends care to correct them?
« Last Edit: 02/23/2013 12:14 PM by antonioe »
ARS LONGA, VITA BREVIS...

Offline antonioe

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I can only assume that Orbital is not telling us all the details, because it seems odd that a helium purge level (?) issue would lead to a two week delay until the next hotfire attempt. Or am I missing something?

Not really: took a few hours to realize the problem was with the valve actuator (not the valve itself) whose torque was marginal, a day or so to find a more powerful actuator that fit in the space available in the ground panel (wanted to avoid re-routing the line to make room for a bigger one - THAT would have taken longer... every time you open a line you have to clean, re-certify it, etc), another day or so to test the result (including stress-testing it to make sure we had plenty of margin) then we also had to replace the engine's throat weather seals that were blown open by the partially-opened valve, inspect the engines to make sure nothing was out of place, close things up, etc. etc...

Oh, and then we had president's day in the middle...

So, overall, pretty standard.

BTW, it was nitrogen, not He.
ARS LONGA, VITA BREVIS...

Offline antonioe

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Here's an interesting piece of trivia:  Bill Wrobel was at the viewing site graciously hosting a bunch of visitors (instead of warm and cozy in the control room like the rest of us... Oh, a Center Director's job is never done...) and he reported that the firing was unusually, eerily quiet... maybe it was because the flame trench pointed away from the stands (about 3 miles away IIRC) and the light wind was blowing behind their backs, but they were all surprised (you can actually hear them talking over the rocket's sound in one of the YouTube videos...)

Of course, this is a BIG problem.  Tourists EXPECT chest-thumping bass undertones in a rocket firing.  Perhaps an actual launch WILL be louder, perhaps the sound will propagate better North-East towards Assatigue (probably the best viewing site.)

As a last resort we can contact Maryland Sound (the Rock Concert AV guys we hire to do the spacecraft acoustic testings at Dulles) and ask them to set microphones around the pad and their [email protected]$$ speakers around the stands for the viewer's benefit...
ARS LONGA, VITA BREVIS...

Offline R7

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firing was unusually, eerily quiet... maybe it was because the flame trench pointed away from the stands (about 3 miles away IIRC) and the light wind was blowing behind their backs, but they were all surprised (you can actually hear them talking over the rocket's sound in one of the YouTube videos...)

The nature's water deluge system was on? Sounded like it was really pouring from the sky.
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Online ugordan

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Perhaps an actual launch WILL be louder

That's a pretty safe bet. Once it clears the pad and noise and exhaust starts bouncing off of the surrounding ground it's bound to get REALLY loud.

Offline antonioe

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firing was unusually, eerily quiet...

The nature's water deluge system was on? Sounded like it was really pouring from the sky.

Well, the rain was officially "light" on the Wx board at the CC (it was barely drizzling when I got outside around 1845) but over 3 miles, I guess that could do it...
ARS LONGA, VITA BREVIS...

Offline Elmar Moelzer

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Urls to the videos, for those who havent found them yet.
« Last Edit: 02/23/2013 02:18 PM by Elmar Moelzer »

Offline R7

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What is the white jet that shoots to the right from the top of the tower couple seconds after ignition, then sputters rest of the burn and stops with the engines?
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Offline Jim

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What is the white jet that shoots to the right from the top of the tower couple seconds after ignition, then sputters rest of the burn and stops with the engines?

GOX vent

Offline Nittany Lion

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Why is the pad called 0A?

The launch pads at Wallops were numbered Launch Area (LA) 1 to 5 from south to north. When the new launch pad for Conestoga was added in the 1990ies south of LA-1, it was called LA-0A. Then a second commercial pad was added as LA-0B.

Offline Lars_J

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I can only assume that Orbital is not telling us all the details, because it seems odd that a helium purge level (?) issue would lead to a two week delay until the next hotfire attempt. Or am I missing something?

Not really: took a few hours to realize the problem was with the valve actuator (not the valve itself) whose torque was marginal, a day or so to find a more powerful actuator that fit in the space available in the ground panel (wanted to avoid re-routing the line to make room for a bigger one - THAT would have taken longer... every time you open a line you have to clean, re-certify it, etc), another day or so to test the result (including stress-testing it to make sure we had plenty of margin) then we also had to replace the engine's throat weather seals that were blown open by the partially-opened valve, inspect the engines to make sure nothing was out of place, close things up, etc. etc...

Oh, and then we had president's day in the middle...

So, overall, pretty standard.

BTW, it was nitrogen, not He.

Thanks for the update, antonioe! And another round of congratulations for the successful test. We are all eagerly awaiting the launch.

Offline Antares

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I'm laying down the following marker:

As long as an EVP/GM from Orbital is posting here for follow up:

Orbital PR >> SpaceX PR

It would be nice to see similar from SpaceX management.  (NSF is probably the most even-handed space portal available for you.)
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Offline kevin-rf

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https://twitter.com/OrbitalSciences/status/306051386011967488

Quote
Prelim inspection shows MARS launch complex in good condition after Friday's 29-second #Antares hold down test.
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