Author Topic: Orbital's Antares Discussion Thread (to Hotfire Test and debut flight)  (Read 31190 times)

Offline Chris Bergin

Specific discussion thread for Antares flow to hotfire and Antares' Debut Flight.

FOR THE SPECIFIC UPDATES (NOT Discussions), SEE THIS THREAD:
http://forum.nasaspaceflight.com/index.php?topic=30921.0

Please note the difference between this thread and the update thread.

For everything else, here's the Party Thread:
http://forum.nasaspaceflight.com/index.php?topic=30923.0

Resources:

Orbital GENERAL Forum Section:
http://forum.nasaspaceflight.com/index.php?board=46.0

Orbital (Antares/Cygnus) News Articles (Recent):
http://www.nasaspaceflight.com/tag/antares/


L2 Antares/Cygnus Section:
http://forum.nasaspaceflight.com/index.php?action=tags&tags=antares
(Includes updates, videos, graphics, presentations and specific interactive posts).

As always, stay on topic and use the correct threads.

Offline Lars_J

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Exciting... But does anyone know any more detail time frame for the hot fire, other than sometime in February?

Offline Chris Bergin

Not yet (as of yesterday), but we'll be eager to know too.

Probably relates to the final cold test in the coming days and the results of it.

Offline Joffan

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I'll be surprised (and impressed) if the COTS 2+ demo goes ahead before July. Similarly I think Orbital's CRS-1 might just about sneak into 2013, but not Q3.
When I say "Jump!", you say "To which orbital inclination?"

Offline yg1968

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Good article, Chris. It's great to have updates on Orbital.
« Last Edit: 01/22/2013 09:47 PM by yg1968 »

Offline Andy DC

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Good article, Chris. It'S great to have updates on Orbital.

Agreed. Another new vehicle and spacecraft in the mix is very positive.

Offline Chris Bergin

Thanks YG and Andy! The good thing about these baseline style articles is it usually shakes the tree for more info.

Offline mr. mark

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I'll be surprised (and impressed) if the COTS 2+ demo goes ahead before July. Similarly I think Orbital's CRS-1 might just about sneak into 2013, but not Q3.
It's already 2013 :o think you meant sneak into 2014.

Offline Lurker Steve

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I'll be surprised (and impressed) if the COTS 2+ demo goes ahead before July. Similarly I think Orbital's CRS-1 might just about sneak into 2013, but not Q3.
It's already 2013 :o think you meant sneak into 2014.

No, that would be slipping. I think his estimate is Q4.

Offline Joffan

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I'll be surprised (and impressed) if the COTS 2+ demo goes ahead before July. Similarly I think Orbital's CRS-1 might just about sneak into 2013, but not Q3.
It's already 2013 :o think you meant sneak into 2014.
It's sometimes hard to convey these things with text only! No, I meant 2013, as Lurker Steve said, and in fact I was thinking Nov/Dec 2013, but please do share your opinion on future Antares activities timing... :)
When I say "Jump!", you say "To which orbital inclination?"

Offline mr. mark

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I think that there was a backlog of activities based on the launch site slip. The schedule though seems to be lining up now and I think that the schedule should be close to the projections.

Offline CNYMike

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Good luck to OSC during Antares' hot fire test and debut flight.
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Offline Prober

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Looking forward to the hot fire test.  Sure the excitement with Orbital will continue to build after that.

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Offline Salo

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http://www.nasa.gov/missions/highlights/schedule.html
Quote
Date: May 3
Mission: Orbital Sciences Corporation Test Flight
Launch Vehicle: Antares/Cygnus
Launch Site: Wallops Flight Facility, Va.
Launch Pad: 0A
Description: The Cygnus spacecraft is scheduled for a demonstration flight on an Orbital Antares launch vehicle under NASA's Commercial Orbital Transportation Services agreement with the company. Cygnus will make an attempt to rendezvous and berth with the International Space Station.

Offline yg1968

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Interesting presentation by Orbital (starts at 34 minutes of the video):
http://www.livestream.com/spaceuphouston/video?clipId=pla_4fa74cb3-ac14-4ee3-a953-d3cc4d5ff87c
« Last Edit: 02/11/2013 03:04 AM by yg1968 »

Offline belegor

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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?

Offline strangequark

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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.

Offline belegor

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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.

Ah, thanks a lot  :)

Offline Phyto

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Just finished reading Orbital tentatively realign Antares hot fire to next week following scrub, good article Chris. Well ahead of postings at the Orbital site.
The choice of the NK-33 has made me nervous for quite a while, though that hasn't been part of Orbital's reported problems as far as I know.
I decided to inform myself about the original engine by reading up on its history at http://www.aerospaceweb.org/question/spacecraft/q0196.shtml
Since both of ULA's rockets (Atlas V and Delta IV) have had good success with ex- & rebuilt Russian/Soviet engines.
Hopefully Orbital hasn't purchased the jinx attached to this engine that eliminated the Soviet Lunar Program.

Offline Jim

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Since both of ULA's rockets (Atlas V and Delta IV) have had good success with ex- & rebuilt Russian/Soviet engines.

Which engine on Delta IV is Russian/Soviet?  And which is one on Atlas is rebuilt?

Offline Phyto

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Since both of ULA's rockets (Atlas V and Delta IV) have had good success with ex- & rebuilt Russian/Soviet engines.

Which engine on Delta IV is Russian/Soviet?  And which is one on Atlas is rebuilt?
Boy, now I've got to go do some more (re)search. (Edit) Maybe I'm confusing the common 2nd stage for linking the two; an Atlas V launch having been delayed due to a problem with a Delta IV launch. (end Edit) I'll get back to you with the answer  :-\ , or stand corrected  :-[ .
(2nd Edit)
Phew! that wasn't so hard. Please check: http://www.nasa.gov/pdf/427652main_PMC_2010_Pech_Russian.pdf
Russian RD-180 Rocket Engine for Atlas V Launch Vehicle - Slide date: 10 Feb 2010

So, it looks like I was wrong about the rebuilt part.  So much info, so little time. . .
I know, excuses, excuses.
« Last Edit: 02/14/2013 07:06 PM by Phyto »

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?

Offline ugordan

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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?

Why should they tell us all the details?

Offline Lars_J

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I'm not saying they should. Just noting the apparent discrepancy between the problem and the fix time.

Offline ugordan

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How long would you expect a "helium purge level" or nitrogen purge as actually mentioned in the release should take to fix? Neither of us has the slightest idea on what, specifically, went wrong so neither of us should assume a given turnaround time is too long.

Offline yg1968

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Quote from: Chris Bergin
Should the next hot fire attempt prove to be successful, the first stage test article will be returned to the Horizontal Integration Facility where the core and two engines will be refurbished for a later flight.

Sorry if this is a dumb question but the engines need to be refurbished after a hot fire test? How long does that take? Is it extensive work?

« Last Edit: 02/14/2013 07:54 PM by yg1968 »

Offline Lurker Steve

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How long would you expect a "helium purge level" or nitrogen purge as actually mentioned in the release should take to fix? Neither of us has the slightest idea on what, specifically, went wrong so neither of us should assume a given turnaround time is too long.

Right, when the computers shutdown the SpaceX hot fire test due to some parameter being out of range, SpaceX just changed the ranges on that parameter instead of determining why it was out of range.

Orbital is trying to learn about the performance of their rocket, and are taking their time to investigate all of the issues.

Offline PreferToLurk

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How long would you expect a "helium purge level" or nitrogen purge as actually mentioned in the release should take to fix? Neither of us has the slightest idea on what, specifically, went wrong so neither of us should assume a given turnaround time is too long.

Right, when the computers shutdown the SpaceX hot fire test due to some parameter being out of range, SpaceX just changed the ranges on that parameter instead of determining why it was out of range.

Orbital is trying to learn about the performance of their rocket, and are taking their time to investigate all of the issues.

That comparison is not fair, the problem with the Spacex hotfire was not the value, but an incorrectly set range.  In such a case fixing the range is proper, and also happens to be easy to do.  There has been no indication that Orbital's problem was simply a bad range. 

Offline kevin-rf

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Just because they identified the cause does not mean the fix is easy. For all we know it might indicate that the purge system is not able to deliver enough N2 for purging. Instead of a software tweak, it may require new plumbing, which will take time.

Orbital has been doing this for a long time, if they say it will take a week to get all the ducks in a row, then Antonioe will have all his ducks in a row before they try again. They decided to not fix it on the fly and try again.

Though I do suspect the Antares could be used to make a mean Peking Duck!
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Offline LouScheffer

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For all we know it might indicate that the purge system is not able to deliver enough N2 for purging. Instead of a software tweak, it may require new plumbing, which will take time.

Not enough N2 would be very odd - I can't believe they would try this for the very first time with 1.5 seconds to go in the countdown - surely they tested the purge before.  I'd suspect some sort of interaction, perhaps with cold/ice from the oxidizer, though this is just a wild guess.

Offline Antares

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Orbital has been doing this for a long time, if they say it will take a week to get all the ducks in a row

Orbital has been doing cryo engines that need purge for a long time?  This was the first attempt at starting a liquid engine at an Orbital launch site.  I could see a couple more of these aborts before it's successful.
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Offline russianhalo117

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Just because they identified the cause does not mean the fix is easy. For all we know it might indicate that the purge system is not able to deliver enough N2 for purging. Instead of a software tweak, it may require new plumbing, which will take time.

Orbital has been doing this for a long time, if they say it will take a week to get all the ducks in a row, then Antonioe will have all his ducks in a row before they try again. They decided to not fix it on the fly and try again.

Though I do suspect the Antares could be used to make a mean Peking Duck!
The purge system worked nominally during the cold flow fluids testing series. So may be something else. AFAIK, GN2 purge system used on AJ-26.62 engines is actually the original NK-33 Heritage GN2 system and so at least on the engine side it dates back a few decades. Outside of the engine all GN2 is new design.
« Last Edit: 02/15/2013 03:19 PM by russianhalo117 »

Offline KSC Sage

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I'm not saying they should. Just noting the apparent discrepancy between the problem and the fix time.

They need to totally understand what the problem was and make sure there is nothing more.  They're retesting the valve and plan the next hotfire test NET next Thursday.

Offline cordor

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Since both of ULA's rockets (Atlas V and Delta IV) have had good success with ex- & rebuilt Russian/Soviet engines.

Which engine on Delta IV is Russian/Soviet?  And which is one on Atlas is rebuilt?
Boy, now I've got to go do some more (re)search. (Edit) Maybe I'm confusing the common 2nd stage for linking the two; an Atlas V launch having been delayed due to a problem with a Delta IV launch. (end Edit) I'll get back to you with the answer  :-\ , or stand corrected  :-[ .
(2nd Edit)
Phew! that wasn't so hard. Please check: http://www.nasa.gov/pdf/427652main_PMC_2010_Pech_Russian.pdf
Russian RD-180 Rocket Engine for Atlas V Launch Vehicle - Slide date: 10 Feb 2010

So, it looks like I was wrong about the rebuilt part.  So much info, so little time. . .
I know, excuses, excuses.

yup, that's RD-180 on Atlas V, Delta IV doesn't use any russian engine. NK family is cursed, N1 was a disaster. Rpk tried to use it and went bankruptcy. Antrares got delayed, how many time exactly?

Offline Jim

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NK family is cursed,

Can't say that.  Antares delays are minor.

Offline russianhalo117

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Since both of ULA's rockets (Atlas V and Delta IV) have had good success with ex- & rebuilt Russian/Soviet engines.

Which engine on Delta IV is Russian/Soviet?  And which is one on Atlas is rebuilt?
Boy, now I've got to go do some more (re)search. (Edit) Maybe I'm confusing the common 2nd stage for linking the two; an Atlas V launch having been delayed due to a problem with a Delta IV launch. (end Edit) I'll get back to you with the answer  :-\ , or stand corrected  :-[ .
(2nd Edit)
Phew! that wasn't so hard. Please check: http://www.nasa.gov/pdf/427652main_PMC_2010_Pech_Russian.pdf
Russian RD-180 Rocket Engine for Atlas V Launch Vehicle - Slide date: 10 Feb 2010

So, it looks like I was wrong about the rebuilt part.  So much info, so little time. . .
I know, excuses, excuses.

yup, that's RD-180 on Atlas V, Delta IV doesn't use any russian engine. NK family is cursed, N1 was a disaster. Rpk tried to use it and went bankruptcy. Antrares got delayed, how many time exactly?
N1 launchers using NK-15 engines were underpowered and NK-15 served as developmental test engine for unflown but more powerful NK-33. NK-33 is a major improvement in terms of design and capability. Yes, its is unflown, but it has continuously proved over decades of testing its overall reliability and performances. The portion of the GN2 Purge system at issue here is not believed to involve the engine itself, but rather portion of the GN2 purge system that ends up connecting to the engine GN2 flow which is the stage one aft compartment GN2 Lines and the interface connecting that stage to its ground-side GN2 GSE. ATM they are trying to figure out where in the GN2 system the off-nominal lack of high pressure occurred when stage one aft compartment and engine final purge was commanded to execute.

Offline cordor

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if i remember correctly, Antares supposed to make first flight last summer, spacex rushed to launch f9 on feb. As soon as osc announced delay to winter, spacex rescheduled f9 to april/may. And then Antares had another delay to this year, and then delay to march.

Im not saying NK is bad engines, they just cause bad luck to whoever use it. call me superstition, hey nasa still pass peanuts every space launch.

Offline sdsds

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NK-33 engines may be finicky, and that may make them tricky to integrate into a vehicle. Although Orbital doesn't have much experience with big liquid engines they have lots of general skillz in dealing with tricky integration issues. They're using those to make sure that when the NK-33 engines on this test unit light up, they behave exactly as expected. If anyone can break the "curse" of a finicky engine design, I'm betting it's Orbital!
-- sdsds --

Offline pippin

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Antrares got delayed, how many time exactly?

If delays are a curse, what does this mean for SpaceX? What was the factor between "SpaceX time" and "real time"? 2.5?
And yet they do fly and even somewhat reliably right now (although still always late)

No, delays for a new launcher are simply normal business.
« Last Edit: 02/17/2013 03:52 AM by pippin »

Offline kch

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call me superstition, hey nasa still pass peanuts every space launch.

Somebody should tell them -- it's bad luck to be superstitious ... :D

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.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

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. :)
When I say "Jump!", you say "To which orbital inclination?"

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?
AD·ASTRA·ASTRORVM·GRATIA

Offline 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 big-@$$ 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.
AD·ASTRA·ASTRORVM·GRATIA

Offline 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.

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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?
AD·ASTRA·ASTRORVM·GRATIA

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.)
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

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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Offline Lurker Steve

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Is there anything significant remaining untested, other than the Cygnus, after the demo flight ?

This flight includes the fairing separation event, and the mass simulator (which should be at least equal to the Cygnus mass) makes it all the way to orbit, right ? So we get a complete test of the first and second stage engines, and all the staging events ?

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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.)
Agreed!
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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?

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


I may have the details wrong...

I can confirm I *DID* have the details wrong... pure flight unit serial numbers start at 0000, not 1000, but there are "6000" series flight units also... perhaps this was a clever tactic developed during the Cold War to keep the US intelligence services confused as to the number of ICBMs they had (ROTFL)... it certainly worked on me!

About the only thing I'm sure is that the "5K/7K" nomenclature derives from the Ukrainian serial number "families" used for test articles...
ARS LONGA, VITA BREVIS...

Online Galactic Penguin SST

http://www.orbital.com/Antares/

Map of the Wallops Island, VA Launch Facilities

July 2012

 In preparation for Orbital's cargo resupply missions to the International Space Station, which will use our Antares rocket and Cygnus spacecraft, significant launch site development has taken place at NASA's Wallops Flight Facility on the eastern shore of Virginia. The aerial map below shows the location of the Mid-Atlantic Regional Spaceport's (MARS) Pad 0A, from which our COTS and CRS missions will launch, as well as the Horizontal Integration Facility (pictured in the previous entry), and Building H-100 Payload Processing Facility on the Wallops main base where Cygnus will be integrated prior to mating with the Antares rocket. The legend on the lower right of the map details all of the facilities that Orbital will utilize in support of the COTS and CRS missions (listed in red). Download a PDF of the map.



Unfortunately this and many other Antares/Cygnus related documents has went missing lately. Anyone got that PDF in hand?
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline Lee Jay

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Given this pad's location, is this vehicle going to fly over a lot of land, and in fact fly to the West of some houses on its way to an ISS orbit?

Online Galactic Penguin SST

Given this pad's location, is this vehicle going to fly over a lot of land, and in fact fly to the West of some houses on its way to an ISS orbit?

They are launching on the descending node for ISS flights (essentially south-east), so it flies straight towards the sea.  :)
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline Lee Jay

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Given this pad's location, is this vehicle going to fly over a lot of land, and in fact fly to the West of some houses on its way to an ISS orbit?

They are launching on the descending node for ISS flights (essentially south-east), so it flies straight towards the sea.  :)

Why didn't I think of that?   :D

Offline baldusi

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Tweet

@OrbitalSciences PR just now: Official Antares Test Flight Date Range: NET April 16, targeted date range of April 16 to 18.[/quote]
« Last Edit: 03/15/2013 09:03 PM by Chris Bergin »

Offline jcm

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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.

And just to amplify that, at LA2 and LA3 there were secondary launch areas called LA2A and LA3A (and possibly LA3B). My understanding is that the Scout orbital launchers were the Mk I tower at LA3 and the Mk II rail at LA3A.
So if WFF were going to be consistent they would have called the new pads 0 and 0A, not 0A and 0B. But these things are rarely consistent.

Hoping someone will correct me if I'm wrong about this.
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Offline ChrisC

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Tweet : @OrbitalSciences PR just now: Official Antares Test Flight Date Range: NET April 16, targeted date range of April 16 to 18.

Confirmed by NASA media accreditation email that went out this evening. "Launch is targeted to occur between April 16-18 at approximately 3 p.m. EDT, the day of launch. "
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Offline ugordan

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Finally, an actual launch date!

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MEDIA ADVISORY: M13-046

NASA MEDIA ACCREDITATION OPEN FOR TEST FLIGHT OF ORBITAL'S ANTARES ROCKET

WALLOPS ISLAND, Va. -- Media accreditation is open for a test flight
of Orbital Sciences Corporation's Antares rocket from the
Mid-Atlantic Regional Spaceport's Pad-0A at NASA's Wallops Flight
Facility in Virginia. Launch is targeted to occur between April 16-18
at approximately 3 p.m. EDT, the day of launch.

Antares is undergoing testing that will enable the rocket to
eventually carry experiments and supplies to the International Space
Station aboard a Cygnus cargo spacecraft. This test flight will not
launch a Cygnus spacecraft or rendezvous with the space station. A
demonstration flight of Cygnus to the orbiting laboratory is planned
for later this year.

International news media representatives without U.S. citizenship must
apply for credentials to cover the prelaunch and launch activities by
March 29. Early accreditation is necessary to process international
media credentials. For media representatives who are U.S. citizens,
the deadline to apply is April 10.

Media should email their accreditation requests to Keith Koehler at
keith.a.koehler@nasa.gov.  For questions about accreditation or
additional information, contact Koehler by email or call him at
757-824-1579.

NASA also is inviting 25 social media users to apply for credentials
for the Antares launch. Social media users selected to attend will be
given the same access as journalists. All social media accreditation
applications will be considered on a case-by-case basis. Registration
for social media accreditation is open online. Because of the
security processing deadline, registration is limited to U.S.
citizens. For U.S. social media, the application deadline is 5 p.m.
March 29. For more information about NASA social media accreditation
requirements and to register, visit:

http://www.nasa.gov/social 

Orbital Sciences Corp. is building and testing its Antares rocket and
Cygnus spacecraft under NASA's Commercial Orbital Transportation
Services (COTS) program. After successful completion of a COTS
demonstration mission to the station, Orbital will begin conducting
eight planned cargo resupply flights to the outpost through NASA's
$1.9 billion Commercial Resupply Services contract with the company.

NASA initiatives, such as COTS, are helping to develop a robust U.S.
commercial space transportation industry. NASA's Commercial Crew
Program also is working with commercial space partners to develop
capabilities to launch U.S. astronauts from American soil during the
next several years.

For more information about the upcoming Orbital test flights and links
to NASA's COTS and Commercial Crew programs, visit:

http://www.nasa.gov/orbital 

For information on Orbital's Antares launch vehicle, visit:

http://www.orbital.com

Offline Danderman

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Tweet : @OrbitalSciences PR just now: Official Antares Test Flight Date Range: NET April 16, targeted date range of April 16 to 18.

Confirmed by NASA media accreditation email that went out this evening. "Launch is targeted to occur between April 16-18 at approximately 3 p.m. EDT, the day of launch. "


The first target launch date for an NK-33 engine, after over 40 years of waiting.

Offline Targeteer

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http://www.orbital.com/Antares-Cygnus/files/AONE-Mission-Overview.pdf

"The “upper stack” (Stage 2, the payload fairing and the payload) will continue on an unpowered trajectory for 93 seconds"

I can't recall an ascent profile that coasts for that long.  Is this just for the test or the normal profile?  Why would such a profile be used? ???
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Offline kevin-rf

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I would assume, since it's a solid and can not be restarted, the ignition is delayed to put in in the correct position to do the orbital insertion burn. The delay allows it to gain some altitude.

I suspect if it ignited immediately after staging you would end up with a very low perigee.
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Offline dunderwood

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Holy gravity losses batman.  Only thing I can surmise is that you don't want to waste impulse pushing the fairing, and don't want to separate the fairing at the lower altitude.  Otherwise I would think you'd accept the higher-but-more-elliptical orbit and let the payload circularize (Cygnus service module in many cases). 

Offline sdsds

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Holy gravity losses batman.

There aren't true gravity losses incurred during a coast phase, since no propellant is expended. (A "true" gravity loss is best exemplified by a vehicle with a T/W ratio of 1.0. It is burning propellant, but going nowhere because of gravity.) If instead of this plan, Antares throttled back the AJ-26 and thus had a longer first stage burn, fighting gravity that longer time ... then it would incur greater gravity losses. AIUI. YMMV. Etc.

What this tells me is that Antares could easily work with a more massive second stage. But then we already knew that....
-- sdsds --

Offline Kabloona

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Holy gravity losses batman.  Only thing I can surmise is that you don't want to waste impulse pushing the fairing, and don't want to separate the fairing at the lower altitude.  Otherwise I would think you'd accept the higher-but-more-elliptical orbit and let the payload circularize (Cygnus service module in many cases). 

This excerpt from the Wikipedia article on "gravity turn" explains why a shorter stage 1 burn and longer coast period can actually be beneficial:

"If the rocket is a multi-stage system where stages fire sequentially, the rocket's ascent burn may not be continuous. Obviously some time must be allowed for stage separation and engine ignition between each successive stage, but some rocket designs call for extra free-flight time between stages. This is particularly useful in very high thrust rockets where if the engines were fired continuously the rocket would run out of fuel before leveling off and reaching a stable orbit above the atmosphere.[2] The technique is also useful when launching from a planet with a thick atmosphere, such as the Earth. Since gravity turns the flight path during free flight the rocket can use a smaller initial pitch over angle, giving it higher vertical velocity, and taking it out of the atmosphere more quickly. This reduces both aerodynamic drag as well as aerodynamic stress during launch. Then later during the flight the rocket coasts between stage firings allowing it to level off above the atmosphere so when the engine fires again, at zero angle of attack, the thrust accelerates the ship horizontally, inserting it into orbit."

See also the Limitations/Max engine thrust paragraph in that article.
« Last Edit: 03/17/2013 12:26 AM by Kabloona »

Offline Antares

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Ugh.  Poor explanations hurt my head.  Solid motors have a fixed impulse so the performance margin is built into the first stage.  Any excess performance is deliberately lost by adjusting (the flight computer onboard does this) the ignition MET for the second stage.  For an underperforming first stage, the ballistic coast will be shorter than 93 seconds.  I guess it's rocket science, but it seems intuitive to me.  In one of these threads, IIRC, the manner in which excess performance of a solid final stage is managed has been discussed.
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Offline Kabloona

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What this tells me is that Antares could easily work with a more massive second stage. But then we already knew that....

The Castor 30A on this flight weighs about 30,000 lbs and the Castor 30XL on later launches weighs about 58,000 lbs, so presumably the S1/2 coast will be shorter with the heavier 30XL.

 Also, when the optional S3 is used they would likely ignite S2 right after staging and trim out performance dispersions by recalculating S3 ignition time as Antares mentioned. So future ascent profiles will be different once they switch to the 30XL and optional third stages.
« Last Edit: 03/17/2013 03:30 PM by Kabloona »

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Tweet : @OrbitalSciences PR just now: Official Antares Test Flight Date Range: NET April 16, targeted date range of April 16 to 18.

Confirmed by NASA media accreditation email that went out this evening. "Launch is targeted to occur between April 16-18 at approximately 3 p.m. EDT, the day of launch. "


The first target launch date for an NK-33 engine, after over 40 years of waiting.


like counting the days.
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Offline arachnitect

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What's the difference between the Castor 30A and 30B motors? Propellant?

Offline Kabloona

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What's the difference between the Castor 30A and 30B motors? Propellant?

According to the ATK catalog, the primary differences are a 26" longer nozzle and a change in propellant. Also, there's about 300 lbs more propellant in the 30B, either because the new propellant is denser or because they tweaked the grain geometry or possibly case insulation thickness to pack a bit more propellant in.

Offline a_langwich

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...
Look up "apex predictor" for that mission - a device that Ernst Stuhlinger built in his garage at home (with the help of a few friends) at von Braun's quiet request before the orbital attempt was approved.. 
http://www.thespacereview.com/article/1224/1
https://docs.google.com/viewer?a=v&q=cache:FrZXUtXXdRcJ:www.jsc.nasa.gov/history/oral_histories/StuhlingerE/ES_5-7-99.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESgCcNobD4kDRJz1s_waDWAZ9aFk32F16vNHlVnbmTsf15tEIsQqcLi9jK_673-f1JlEsXnf-1Qkuotc6wRPfarBQHpeXoMasJRDFRz-wxh5w0qHELFAYzKGnXcRZSRbW_8oBrax&sig=AHIEtbS6se8W3dlGSy3Dpd1EFW8D9eK3CA

 - Ed Kyle

Oooh, thank you very much.  Links like that are nuggets of gold.

Offline Lurker Steve

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Ugh.  Poor explanations hurt my head.  Solid motors have a fixed impulse so the performance margin is built into the first stage.  Any excess performance is deliberately lost by adjusting (the flight computer onboard does this) the ignition MET for the second stage.  For an underperforming first stage, the ballistic coast will be shorter than 93 seconds.  I guess it's rocket science, but it seems intuitive to me.  In one of these threads, IIRC, the manner in which excess performance of a solid final stage is managed has been discussed.

That's part of it.  Another part is the fact that solid motors have relatively short burn times (and higher thrust) compared to most liquid upper stages.  The physics of typical ascent trajectories means that several minutes (eight or nine or more minutes) must pass before the final thrust can be applied at the proper altitude to reach orbital velocity.  If it is a long-burning, low thrust liquid engine, that thrust can be applied all the way up.  If it is a short-buring, high thrust solid, there needs to be a coast period.

 - Ed Kyle

Out of curiosity, given equivalent thrust, which weighs more, a solid upper stage like the Castor 30 or a fully fueled LH2(or RP1)/LOX upper stage utilizing a "generic" US engine like the RD-0124 or AJ-10 ?

Offline Kabloona

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Out of curiosity, given equivalent thrust, which weighs more, a solid upper stage like the Castor 30 or a fully fueled LH2(or RP1)/LOX upper stage utilizing a "generic" US engine like the RD-0124 or AJ-10 ?


For comparison here are Centaur specs from the 2010 Atlas V user's guide and Castor 30B specs from the ATK catalog:

Centaur
Prop mass: 45,922 lbm
Engines: 1/2
Thrust: 22,300/44,600 lbf
Burn time 926/463 sec

Castor 30B
Prop mass: 28,412 lbm
Thrust: 67,370 lbf (avg)
Burn time: 127 sec

For comparably sized upper stages, the solid will burn with higher thrust and shorter burn time due to the different physics of solid and liquid propellants. Solids have an inherent mass flow (hence thrust) advantage because the propellant doesn't have to be pumped through injectors, and their mass flow rate is limited only by the grain surface area and burn rate.
« Last Edit: 03/18/2013 02:14 PM by Kabloona »

Offline baldusi

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Let me make a slight point about three first stages that are quite "comparable": Zenit-2, Atlas V and Antares:

RocketZenit-2Atlas V (4xx)Antares
Wet Weight (kg)354,582306,274248,400
SL Thrust (MN)7.2523.8273.265
T/W (wet stage)2.091.281.34
SL isp (s)309.5311297
pmf (%)90.89%92.76%96.38%
Width (m)3.9m3.8m3.9m
Height (m)32.90m32.46m27.60m
W/H Ratio8.448.527.26

If you look at it you'll see that the Antares 100 first stage is pretty close to an 85% of an Atlas V 400 first stage. Thus, it can't really take "too" big an upper stage, because the total T/W would be too low. And it has worse isp (but better pmf).
I believe that it couldn't take an US bigger than 20,000kg (or so). A Centaur would likely be the limit. Else it would fall below 1.2 T/W. A whole Blok I would be slightly "too big". When you look at it, the ideal US for the Antares would have been the Centaur.

Offline Kabloona

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I believe that it couldn't take an US bigger than 20,000kg (or so). A Centaur would likely be the limit.


Castor 30XL is around 26,300 kg, heavier than Centaur, and one would assume that, since the 30 XL is a stretch version designed for this purpose, they went to the limit of stage 1 capacity. So Castor 30XL is likely the limit, I would think.
« Last Edit: 03/18/2013 03:59 PM by Kabloona »

Offline baldusi

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I believe that it couldn't take an US bigger than 20,000kg (or so). A Centaur would likely be the limit.


Castor 30XL is around 26,300 kg, heavier than Centaur, and one would assume that, since the 30 XL is a stretch version designed for this purpose, they went to the limit of stage 1 capacity. So Castor 30XL is likely the limit, I would think.
Yes. I'm starting to suspect my first stage numbers. But it's also true that a 27tonnes plus 3tonnes of fairing plus 7tonnes of payload was about 1.15 T/W. Which probably is the true limit.

Offline Kabloona

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Yes. I'm starting to suspect my first stage numbers. But it's also true that a 27tonnes plus 3tonnes of fairing plus 7tonnes of payload was about 1.15 T/W. Which probably is the true limit.

This source has S1 wet mass of 260,700 kg and vehicle liftoff mass of 282,00 kg (presumably that is the Castor 30A/B config). Don't know how accurate it is.

http://www.spaceflight101.com/antares-launch-vehicle-information.html
« Last Edit: 03/18/2013 05:41 PM by Kabloona »

Offline tnphysics

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Let me make a slight point about three first stages that are quite "comparable": Zenit-2, Atlas V and Antares:

RocketZenit-2Atlas V (4xx)Antares
Wet Weight (kg)354,582306,274248,400
SL Thrust (MN)7.2523.8273.265
T/W (wet stage)2.091.281.34
SL isp (s)309.5311297
pmf (%)90.89%92.76%96.38%
Width (m)3.9m3.8m3.9m
Height (m)32.90m32.46m27.60m
W/H Ratio8.448.527.26

If you look at it you'll see that the Antares 100 first stage is pretty close to an 85% of an Atlas V 400 first stage. Thus, it can't really take "too" big an upper stage, because the total T/W would be too low. And it has worse isp (but better pmf).
I believe that it couldn't take an US bigger than 20,000kg (or so). A Centaur would likely be the limit. Else it would fall below 1.2 T/W. A whole Blok I would be slightly "too big". When you look at it, the ideal US for the Antares would have been the Centaur.


One interesting consequence of the Antares 100 first stage's very large mass ratio is that it is capable of lifting about 2,891 kg to orbit as an SSTO, assuming a delta-V of 9250 m/s. This number is before the first stage guidance systems, payload fairing, etc. are included.

Offline anik

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If I understood correctly, there will be Soyuz-2-1V first stage's hotfire test in Russia close to April 16. Are Orbital guys waiting for results from NK-33A hotfire test? Or is it just coincidence that Antares's debut launch is planned after hotfire test in Russia? :)
« Last Edit: 03/21/2013 05:35 PM by anik »

Offline strangequark

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Let me make a slight point about three first stages that are quite "comparable": Zenit-2, Atlas V and Antares:

RocketZenit-2Atlas V (4xx)Antares
Wet Weight (kg)354,582306,274248,400
SL Thrust (MN)7.2523.8273.265
T/W (wet stage)2.091.281.34
SL isp (s)309.5311297
pmf (%)90.89%92.76%96.38%
Width (m)3.9m3.8m3.9m
Height (m)32.90m32.46m27.60m
W/H Ratio8.448.527.26

If you look at it you'll see that the Antares 100 first stage is pretty close to an 85% of an Atlas V 400 first stage. Thus, it can't really take "too" big an upper stage, because the total T/W would be too low. And it has worse isp (but better pmf).
I believe that it couldn't take an US bigger than 20,000kg (or so). A Centaur would likely be the limit. Else it would fall below 1.2 T/W. A whole Blok I would be slightly "too big". When you look at it, the ideal US for the Antares would have been the Centaur.


As a general LV design comment, that is kind of the purpose of strap-on solids; to boost initial T/W while the rocket is fully loaded.

Don't forget too that Aerojet has publicly committed to 500klbf for domestically produced AJ-26s. There's "easy" upgrade paths out there, if there's ever a desire.
« Last Edit: 03/21/2013 06:35 PM by strangequark »

Offline Prober

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If I understood correctly, there will be Soyuz-2-1V first stage's hotfire test in Russia close to April 16. Are Orbital guys waiting for results from NK-33A hotfire test? Or is it just coincidence that Antares's debut launch is planned after hotfire test in Russia? :)
Not related, different setup
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Offline Lurker Steve

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Let me make a slight point about three first stages that are quite "comparable": Zenit-2, Atlas V and Antares:

RocketZenit-2Atlas V (4xx)Antares
Wet Weight (kg)354,582306,274248,400
SL Thrust (MN)7.2523.8273.265
T/W (wet stage)2.091.281.34
SL isp (s)309.5311297
pmf (%)90.89%92.76%96.38%
Width (m)3.9m3.8m3.9m
Height (m)32.90m32.46m27.60m
W/H Ratio8.448.527.26

If you look at it you'll see that the Antares 100 first stage is pretty close to an 85% of an Atlas V 400 first stage. Thus, it can't really take "too" big an upper stage, because the total T/W would be too low. And it has worse isp (but better pmf).
I believe that it couldn't take an US bigger than 20,000kg (or so). A Centaur would likely be the limit. Else it would fall below 1.2 T/W. A whole Blok I would be slightly "too big". When you look at it, the ideal US for the Antares would have been the Centaur.


As a general LV design comment, that is kind of the purpose of strap-on solids; to boost initial T/W while the rocket is fully loaded.

Don't forget too that Aerojet has publicly committed to 500klbf for domestically produced AJ-26s. There's "easy" upgrade paths out there, if there's ever a desire.

Is there going to be a significant change in ISP with the Aerojet AJ-26-500s ? I was wondering if the new engines would require stretching the first stage a little bit, putting it even closer to the size/weight of the Atlas V first stage.

Offline russianhalo117

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If I understood correctly, there will be Soyuz-2-1V first stage's hotfire test in Russia close to April 16. Are Orbital guys waiting for results from NK-33A hotfire test? Or is it just coincidence that Antares's debut launch is planned after hotfire test in Russia? :)
No, 16-18 are the earliest dates approved by USAF for Antares test flight A-One from US Eastern Test Range. AFAIK, Soyuz 2-1V moved their previous hotfire date due to on same day after the first Antares hotfire test abort. A TsKB Delegation was present for both Antares hotfire attempts because of engine commonality as was the presence awhile back of a joint US Orbital/Aerojet delegation at last years failed Soyuz 2-1V first stage hotfire attempt and this years last NK-33A standalone hotfire test. The engine purge system for AJ-26.62 is almost identical to that NK-33A. So that is one of the reasons why TsKB moved their next hotfire test to April so that they could perform verification work on the test stand and stage one. I have not found confirmation of this Anik, but they are to rollout the 2-1V test article first to conduct a full test of the test stand's emergency systems as well as the stand's repaired systems ahead of the planned hotfire test. The 2-1V test article is currently ready for its tests and might rollout as early as Monday next week and remain at the test stand for the hotfire test if no major problems crop and force its rollback. That is what I know to date.

Offline strangequark

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Is there going to be a significant change in ISP with the Aerojet AJ-26-500s ? I was wondering if the new engines would require stretching the first stage a little bit, putting it even closer to the size/weight of the Atlas V first stage.

I don't have any special knowledge on AJ-26-500 (and couldn't share it if I did). As speculation, Aerojet will almost definitely increase thrust by uprating the chamber pressure. This would allow the use of a longer expansion ratio nozzle while maintaining the same exit pressure, and would increase Isp.

So, there's definitely potential for it.

Offline Comga

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Just noticed this from the AONE-Mission Overview PDF.
The fairing is jettisoned BEFORE second stage ignition while the stack is in freefall. 
Why is this supperior to jettison while accelerating?  There is excess capacity being trimmed as gravity losses in the adjustable duration of the long coast.  Why not start accelerating earlier and jettison a few seconds later while the acceration can help the fairing halves depart?
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Kryten

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 The second stage is inside the fairing, isn't it? How could it possibly ignite before fairing separation?

Offline Silmfeanor

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The second stage is inside the fairing, isn't it? How could it possibly ignite before fairing separation?

Comga means during 1st stage flight

Offline Kabloona

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Just noticed this from the AONE-Mission Overview PDF.
The fairing is jettisoned BEFORE second stage ignition while the stack is in freefall. 
Why is this supperior to jettison while accelerating?  There is excess capacity being trimmed as gravity losses in the adjustable duration of the long coast.  Why not start accelerating earlier and jettison a few seconds later while the acceration can help the fairing halves depart?

It may be because of the way the interstage is designed. If you look closely at that graphic, you can see both halves of the PLF and the interstage ring falling away from S2. So S1 separates below the interstage, and then the PLF and interstage separate from S2.

If that is in fact how it works, then the interstage can't be separated during S2 firing because of the possibility it could contact the nozzle. So the interstage and PLF must be jettisoned first.

Plus, there's no point wasting deltaV, no matter how little, on the PLF that you're jettisoning. It's designed to jettison all by itself without needing any deltaV from S2. Only reason to delay PLF jettison is atmospherics, and apparently it'll be high enough before S2 igntion anyway.

The cutaway in this brochure shows more clearly how the interstage works.

http://www.orbital.com/NewsInfo/Publications/Antares_Brochure.pdf

Could be wrong but that's my hypothesis.
« Last Edit: 04/08/2013 11:38 PM by Kabloona »

Offline Comga

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The second stage is inside the fairing, isn't it? How could it possibly ignite before fairing separation?

Comga means during 1st stage flight

Thanks but no, I just forgot about that little interstage, and how it is what holds the fairing.  I was going to ask about that but didn't to keep the post short.

That's the answer.  The second stage would have to drag that interstage to keep the fairing with it.

It is an intersting set of system choices.  Many are the polar opposites of "the other CRS provider."
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Kabloona

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The second stage is inside the fairing, isn't it? How could it possibly ignite before fairing separation?

Comga means during 1st stage flight

It is an intersting set of system choices.  Many are the polar opposites of "the other CRS provider."

The difference from F9 being that the Castor 30 is a smaller diameter than S1, and thus you need the conical adapter ring, as opposed to F9's simpler load path through S2.

So in this case it's the dimensions of the Castor 30 that drives the interstage design and staging sequence.

Offline Lurker Steve

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I was wondering exactly how large of a payload Antares could deliver to GTO. My thinking was that Orbital could be a "single-source" supplier that eventually they would be a one-stop shop where Intelsat or SES would purchase a SAT with X amount of transpoders, and Orbital could put that into the correct orbit using Antares.

It looks like a SAT the size of SES-8 is about 3.5 mT, so that's probably out of their range at the moment.

Offline Jim

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I was wondering exactly how large of a payload Antares could deliver to GTO. My thinking was that Orbital could be a "single-source" supplier

Not usually done.  See Boeing and LM spacecraft
« Last Edit: 04/12/2013 09:22 PM by Jim »

Offline baldusi

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I was wondering exactly how large of a payload Antares could deliver to GTO. My thinking was that Orbital could be a "single-source" supplier that eventually they would be a one-stop shop where Intelsat or SES would purchase a SAT with X amount of transpoders, and Orbital could put that into the correct orbit using Antares.

It looks like a SAT the size of SES-8 is about 3.5 mT, so that's probably out of their range at the moment.
Both Boeing and LM produce satellites and LV they don't fly together, usually. And Antares has a vry high inclination launch site (Wallops) with a very low energy US, which is a very bad stack for GTO. OSC is managed as a business, and their satellite unit does what's best for their bottom line, and the LV unit makes the business they think they can get the better profit of. In the particular case of Antares they'll earn a profit if it only flies for COTS/CRS, and have a chance to get an extra buck by being a Delta II replacement.

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