Author Topic: LIVE: Ares I/SD HLV Five Segment DM-2 Test - Aug 31, 2010 (Read 64841 times)

Chris Bergin · « **on:** 08/31/2010 12:55 pm »

Live coverage of the ATK firing in Utah.

Article:
http://www.nasaspaceflight.com/2010/08/live-atk-dm-2-test-inline-sd-hlv-nasa-support/

====
Please note, this will be a live thread for screenshots and coverage - so only post updates during the business end of the countdown.

Space Invaders · « **Reply #1 on:** 08/31/2010 01:01 pm »

Is there any live video feed available? Thanks.

Chris Bergin · « **Reply #2 on:** 08/31/2010 01:04 pm »

Quote from: Space Invaders on 08/31/2010 01:01 pm

Is there any live video feed available? Thanks.

Will be on NTV:

http://www.nasa.gov/multimedia/nasatv/index.html?param=public

Chris Bergin · « **Reply #3 on:** 08/31/2010 01:05 pm »

Also note previous thread for DM-2:
http://forum.nasaspaceflight.com/index.php?topic=20350.0

And DM-1's coverage:
http://forum.nasaspaceflight.com/index.php?topic=15701.0

ATK's promo:

rsnellenberger · « **Reply #4 on:** 08/31/2010 01:42 pm »

Quote from: Chris Bergin on 08/31/2010 01:05 pm

ATK's promo:

That was kinda painful...

daveglo · « **Reply #5 on:** 08/31/2010 02:05 pm »

The article says 9:26 MDT (3:26 GMT), but the promo video said 9:05 MDT? Is that webcast start time or just an out-of-date reference?

Calphor · « **Reply #6 on:** 08/31/2010 02:17 pm »

Quote from: daveglo on 08/31/2010 02:05 pm

The article says 9:26 MDT (3:26 GMT), but the promo video said 9:05 MDT? Is that webcast start time or just an out-of-date reference?

It's an out of date reference. The time was recently changed to 9:26 MDT.

Ancient · « **Reply #7 on:** 08/31/2010 02:21 pm »

Why was the engineer standing right behind the nozzle at the end of the video while the audio track has the test conductor calling, "fire"?

psloss · « **Reply #8 on:** 08/31/2010 02:31 pm »

Some notes, links, updates here:
http://twitter.com/NASA_Ares

And here:
http://twitter.com/ATKRocketNews

(Lots of "cross-tweeting", so one or the other may work by itself.)

Ronsmytheiii · « **Reply #9 on:** 08/31/2010 02:35 pm »

t-49 minutes, one hold expected at t-9 min for 5 min

Space Pete · « **Reply #10 on:** 08/31/2010 02:38 pm »

Some components of DM-2 were used to launch the HST (STS-31) and Node 1 (STS-88)! The most recently flown components are from STS-126!

(Via Robert Pearlman/collectSPACE.)

Comga · « **Reply #11 on:** 08/31/2010 02:39 pm »

Quote from: Ancient on 08/31/2010 02:21 pm

Why was the engineer standing right behind the nozzle at the end of the video while the audio track has the test conductor calling, "fire"?

Because
1) There are things in there to be discovered?
2) There is no better way to remove that two day stubble?
3) He has decided that the future they are buiding is not really better?

Yes rsnellenberger, pretty painful to watch

psloss · « **Reply #12 on:** 08/31/2010 02:41 pm »

OK, maybe some better updates here:
http://twitter.com/MarkKirkman

kch · « **Reply #13 on:** 08/31/2010 02:43 pm »

Quote from: Ancient on 08/31/2010 02:21 pm

Why was the engineer standing right behind the nozzle at the end of the video while the audio track has the test conductor calling, "fire"?

Those two never did get along -- "problem solved" ...

Chris Bergin · « **Reply #14 on:** 08/31/2010 03:04 pm »

15 minutes to live coverage.

Chris Bergin · « **Reply #15 on:** 08/31/2010 03:16 pm »

Chris Bergin · « **Reply #16 on:** 08/31/2010 03:21 pm »

T-7 minutes.

Chris Bergin · « **Reply #17 on:** 08/31/2010 03:21 pm »

psloss · « **Reply #18 on:** 08/31/2010 03:22 pm »

Don't hear any commentary, per se, yet. Just the test personnel with the countdown. (Probably works for many in the audience here.

)

Chris Bergin · « **Reply #19 on:** 08/31/2010 03:22 pm »

Chris Bergin · « **Reply #20 on:** 08/31/2010 03:22 pm »

Water boost pump is on.

Chris Bergin · « **Reply #21 on:** 08/31/2010 03:23 pm »

T-5 minutes. High speed cameras on.

Chris Bergin · « **Reply #22 on:** 08/31/2010 03:24 pm »

Chris Bergin · « **Reply #23 on:** 08/31/2010 03:24 pm »

Chris Bergin · « **Reply #24 on:** 08/31/2010 03:25 pm »

Polling is go.

Chris Bergin · « **Reply #25 on:** 08/31/2010 03:25 pm »

Aft skirt conditioning to off.

Chris Bergin · « **Reply #26 on:** 08/31/2010 03:26 pm »

High speed cameras now recording

Chris Bergin · « **Reply #27 on:** 08/31/2010 03:26 pm »

Ignitor joint heater to off.

Chris Bergin · « **Reply #28 on:** 08/31/2010 03:27 pm »

Commit the motor.

Chris Bergin · « **Reply #29 on:** 08/31/2010 03:27 pm »

T-60 seconds. Sirens blaring.

Chris Bergin · « **Reply #30 on:** 08/31/2010 03:28 pm »

T-30 seconds

Chris Bergin · « **Reply #31 on:** 08/31/2010 03:28 pm »

Ignition!

Chris Bergin · « **Reply #32 on:** 08/31/2010 03:28 pm »

Chris Bergin · « **Reply #33 on:** 08/31/2010 03:28 pm »

Chris Bergin · « **Reply #34 on:** 08/31/2010 03:29 pm »

T+1 minute.

Chris Bergin · « **Reply #35 on:** 08/31/2010 03:29 pm »

Chris Bergin · « **Reply #36 on:** 08/31/2010 03:29 pm »

Big crowd

Chris Bergin · « **Reply #37 on:** 08/31/2010 03:30 pm »

Chris Bergin · « **Reply #38 on:** 08/31/2010 03:30 pm »

Burnout..

Chris Bergin · « **Reply #39 on:** 08/31/2010 03:31 pm »

robertross · « **Reply #40 on:** 08/31/2010 03:31 pm »

Wow, quite a smoke plume after the fact!

Space Pete · « **Reply #41 on:** 08/31/2010 03:32 pm »

Now THAT was awesome!

Chris Bergin · « **Reply #42 on:** 08/31/2010 03:32 pm »

robertross · « **Reply #43 on:** 08/31/2010 03:34 pm »

the smoke coming out of the SRB now looks like a dry ice making machine (as it hugs the ground).

Chris Bergin · « **Reply #44 on:** 08/31/2010 03:34 pm »

Six minutes after ignition:

Chris Bergin · « **Reply #45 on:** 08/31/2010 03:35 pm »

Test area appears to be in a nominal state. Some gassing from the north side, but they believe that's the cold conditions.

Chris Bergin · « **Reply #46 on:** 08/31/2010 03:35 pm »

Shutting down the testing hardware.

Chris Bergin · « **Reply #47 on:** 08/31/2010 03:36 pm »

Crews to check for hydrazine, fires and hot spots.

psloss · « **Reply #48 on:** 08/31/2010 03:36 pm »

Quote from: robertross on 08/31/2010 03:34 pm

the smoke coming out of the SRB now looks like a dry ice making machine (as it hugs the ground).

Yeah, that arm that goes into the motor is pumping CO2 in.

Chris Bergin · « **Reply #49 on:** 08/31/2010 03:37 pm »

T+9 mins.

robertross · « **Reply #50 on:** 08/31/2010 03:37 pm »

Quote from: psloss on 08/31/2010 03:36 pm

Quote from: robertross on 08/31/2010 03:34 pm
the smoke coming out of the SRB now looks like a dry ice making machine (as it hugs the ground).
Yeah, that arm that goes into the motor is pumping CO2 in.

Well that explains that...thanks.

psloss · « **Reply #51 on:** 08/31/2010 03:39 pm »

Report of hydrazine indications in the parking lot; planning to evacuate the instrument room.

Chris Bergin · « **Reply #52 on:** 08/31/2010 03:40 pm »

They are detecting hydrazine. Evacuating the room being used by the fire crew - when they see some clear air.

Assume they will be in SCAPE suits anyway!

MikeMi. · « **Reply #53 on:** 08/31/2010 03:40 pm »

Quote from: robertross on 08/31/2010 03:37 pm

Quote from: psloss on 08/31/2010 03:36 pm
Quote from: robertross on 08/31/2010 03:34 pm
the smoke coming out of the SRB now looks like a dry ice making machine (as it hugs the ground).
Yeah, that arm that goes into the motor is pumping CO2 in.

Well that explains that...thanks.

Here is seen :

Chris Bergin · « **Reply #54 on:** 08/31/2010 03:43 pm »

Looks like they cut the live feed and are replaying the event from T-6 mins.

Chris Bergin · « **Reply #55 on:** 08/31/2010 03:49 pm »

Managed to grab a shot right at ignition from the replay

robertross · « **Reply #56 on:** 08/31/2010 03:50 pm »

Quote from: Chris Bergin on 08/31/2010 03:49 pm

Managed to grab a shot right at ignition from the replay

Quite a shock wave too! (when it hit the camera)

John44 · « **Reply #57 on:** 08/31/2010 03:57 pm »

Development Motor 2 Static Test Fire
http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=6128

psloss · « **Reply #58 on:** 08/31/2010 03:58 pm »

Quote from: Chris Bergin on 08/31/2010 03:43 pm

Looks like they cut the live feed and are replaying the event from T-6 mins.

And again from the top. They may be running it in a loop until the press conference.

Chris Bergin · « **Reply #59 on:** 08/31/2010 03:59 pm »

They went all the way through that replay but then stopped before the hydrazine leak was noted on the loop. And we're back into another run of the same replay, for a third time, from T-6 minutes.

rcoppola · « **Reply #60 on:** 08/31/2010 04:25 pm »

DM 2 Youtube:

Chris Bergin · « **Reply #61 on:** 08/31/2010 04:32 pm »

Doug: Nothing better for an engineer than to see a test like this. So far looks like an excellent and successful test.

Chris Bergin · « **Reply #62 on:** 08/31/2010 04:33 pm »

Doug on funding: "This is funded under our current project. We're in an uncertain period right now. It will need the kind of tests we see today."

Chris Bergin · « **Reply #63 on:** 08/31/2010 04:34 pm »

Alex: "Prelim data looks good."

Chris Bergin · « **Reply #64 on:** 08/31/2010 04:36 pm »

ATK boss is happy, nothing critical skills within the workforce.

Chris Bergin · « **Reply #65 on:** 08/31/2010 04:40 pm »

Doug notes it takes this sort of capability to get beyond LEO. It's all contributing towards the decisions.

Mark K! Asking about mapping out the future tests.

Doug notes future depends on funding. Alex notes four DMs and then QMs (qualification motors). Next, DM-3 is a hot fire test, compared today's cold fire test. DM-4 cold test. QMs are indentical.

Downix · « **Reply #66 on:** 08/31/2010 04:41 pm »

I understand the weight loss of the new design, has any hard numbers as to the weight loss shown up?

Chris Bergin · « **Reply #67 on:** 08/31/2010 04:42 pm »

Still executing the POR with 4 DMs (two more) and three QMs.

Lars_J · « **Reply #68 on:** 08/31/2010 04:47 pm »

Quote from: Chris Bergin on 08/31/2010 04:40 pm

Doug notes it takes this sort of capability to get beyond LEO.

Ha!

MarsMethanogen · « **Reply #69 on:** 08/31/2010 04:49 pm »

OK, so what's the difference between a hot-fire test and a cold-fire test? Today's test looked pretty hot to me.

Chris Bergin · « **Reply #70 on:** 08/31/2010 04:54 pm »

All very much the same sort of questions (apart from Mark Kirkman who asked a specific question). ATK head noting that nothing compares with the booster's capability.

Doug notes they have been studying SD, RP-1 etc HLVs for over half a year. Getting a pretty good understanding.

James Dean asks about costs:

Test costs around $75m. About one billion dollars spent to date on the five seg.

Mark asking on future I-X type tests under POR:

Doug notes possibilities are being considered, but it's up in the air and nothing concrete.

Chris Bergin · « **Reply #71 on:** 08/31/2010 04:55 pm »

Aug. 31, 2010

RELEASE: 10-202

CORRECTION -- NASA AND ATK SUCCESSFULLY TEST FIVE-SEGMENT SOLID ROCKET MOTOR

CORRECTION - Number of flights of DM-2 motor cases and specific
missions flown
(The number of flights the DM-2 motor cases had flown was erroneously
reported. The correct number is 59. The earliest mission the cases
flew was STS-3. Please use the corrected version of this news
release.)

PROMONTORY, Utah -- With a loud roar and mighty column of flame, NASA
and ATK Aerospace Systems successfully completed a two-minute,
full-scale test of the largest and most powerful solid rocket motor
designed for flight. The motor is potentially transferable to future
heavy-lift launch vehicle designs.

The stationary firing of the first-stage development solid rocket
motor, dubbed DM-2, was the most heavily instrumented solid rocket
motor test in NASA history. More than 760 instruments measured 53
test objectives.

Prior to the static test, the solid rocket motor was cooled to 40
degrees Fahrenheit to verify the performance of new materials and
assess motor performance at low temperatures during the full-duration
test. Initial test data showed the motor performance met all
expectations.

"For every few degrees the temperature rises, solid propellant burns
slightly faster and only through robust ground testing can we
understand how material and motor performance is impacted by
different operating conditions," said Alex Priskos, first stage
manager for Ares Projects at NASA's Marshall Space Flight Center in
Huntsville, Ala. "Ground-testing at temperature extremes pushes this
system to its limits, which advances our understanding of
five-segment solid rocket motor performance."

The first-stage solid rocket motor is designed to generate up to
3.6-million pounds of thrust at launch. Information collected from
this test, together with data from the first development motor test
last year, will be evaluated to better understand the performance and
reliability of the design.

Although similar to the solid rocket boosters that help power the
space shuttle to orbit, the five-segment development motor includes
several upgrades and technology improvements implemented by NASA and
ATK engineers. Motor upgrades from a shuttle booster include the
addition of a fifth segment, a larger nozzle throat, and upgraded
insulation and liner. The motor cases are flight-proven hardware used
on shuttle launches for more than three decades. The cases used in
this ground test have collectively launched 59 previous missions, the
earliest being STS-3.

After more testing, the first-stage solid rocket motor will be
certified to fly at temperature ranges between 40-90 degrees
Fahrenheit. The solid rocket motor was built as an element of NASA's
Constellation Program and is managed by the Ares Projects Office at
Marshall. ATK Aerospace Systems, a division of Alliant Techsystems of
Brigham City, Utah, is the prime contractor.

For more information about NASA, visit:

http://www.nasa.gov

Chris Bergin · « **Reply #72 on:** 08/31/2010 04:56 pm »

That does it for coverage.

John44 · « **Reply #73 on:** 08/31/2010 05:15 pm »

Post Development Motor 2 Static Test Fire News Conference
http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=6130

Jim · « **Reply #74 on:** 08/31/2010 05:54 pm »

Quote from: MarsMethanogen on 08/31/2010 04:49 pm

OK, so what's the difference between a hot-fire test and a cold-fire test? Today's test looked pretty hot to me.

outside environment. This one was cold soaked

rcoppola · « **Reply #75 on:** 08/31/2010 06:19 pm »

At some point very soon, ATK will be told to make adjustments to facilitate the 5seg for HLV use and not as a first stage for A1. I wonder exactly what would need to be altered in the current design? The throat? The vectoring? Any thoughts?

Pheogh · « **Reply #76 on:** 08/31/2010 06:49 pm »

Quote from: rcoppola on 08/31/2010 06:19 pm

At some point very soon, ATK will be told to make adjustments to facilitate the 5seg for HLV use and not as a first stage for A1. I wonder exactly what would need to be altered in the current design? The throat? The vectoring? Any thoughts?

right off the bat you could lose the vectoring? I would suspect 3 or 4 SSME's have enough control authority to turn the stack, no?

I would suspect it would save some money as well?

PahTo · « **Reply #77 on:** 08/31/2010 07:07 pm »

There has been discussion about reducing or removing TVC from the SRMs in a SDHLV (was this true of AresV as well?). I'm curious what kind of performance can be expected from a (R)SRM with reduced mass due to less/loss of TVC, and use of HTPB (in Isp). And is the 5-seg still being considered for re-usability? I reckon those 'chutes weigh quite a bit too...

rcoppola · « **Reply #78 on:** 08/31/2010 07:14 pm »

Quote from: PahTo on 08/31/2010 07:07 pm

There has been discussion about reducing or removing TVC from the SRMs in a SDHLV (was this true of AresV as well?). I'm curious what kind of performance can be expected from a (R)SRM with reduced mass due to less/loss of TVC, and use of HTPB (in Isp). And is the 5-seg still being considered for re-usability? I reckon those 'chutes weigh quite a bit too...

Re-usability continues to be a definite. As for the TVC, I just wonder what the new center of gravity with an in-line does to the TVC needs of the SRB's. Just not sure the SSME can do all the vectoring on their own. But I just don't know. Unfortunately, not a rocket scientist, unlike some other fellow NSFers....

robertross · « **Reply #79 on:** 08/31/2010 07:27 pm »

Quote from: rcoppola on 08/31/2010 07:14 pm

Quote from: PahTo on 08/31/2010 07:07 pm

There has been discussion about reducing or removing TVC from the SRMs in a SDHLV (was this true of AresV as well?). I'm curious what kind of performance can be expected from a (R)SRM with reduced mass due to less/loss of TVC, and use of HTPB (in Isp). And is the 5-seg still being considered for re-usability? I reckon those 'chutes weigh quite a bit too...

Re-usability continues to be a definite. As for the TVC, I just wonder what the new center of gravity with an in-line does to the TVC needs of the SRB's. Just not sure the SSME can do all the vectoring on their own. But I just don't know. Unfortunately, not a rocket scientist, unlike some other fellow NSFers....

This was recently talked about in another thread (the Direct thread IIRC). Jim had indicated a potential problem with the lackof TVC at SRB tail-off, where you really need to have a sufficient thrust off-center to adjust a change in course. Now of course with a change from 104.5% to 'potentially' 109%, it changes things a little bit, but not that much.

It will be interesting to see how this plays out.

robertross · « **Reply #80 on:** 08/31/2010 07:30 pm »

Quote from: rcoppola on 08/31/2010 06:19 pm

At some point very soon, ATK will be told to make adjustments to facilitate the 5seg for HLV use and not as a first stage for A1. I wonder exactly what would need to be altered in the current design? The throat? The vectoring? Any thoughts?

That has yet to be determined. It could be we stick with 4-segment, or we get a 4+dummy Ares I-X style for future requirements (doubtful), or yes it could go all the way to a 5-segment for a J-246 variant. Time will tell, but in any case ATK won't be hurting.

rcoppola · « **Reply #81 on:** 08/31/2010 07:38 pm »

Quote from: robertross on 08/31/2010 07:30 pm

Quote from: rcoppola on 08/31/2010 06:19 pm
At some point very soon, ATK will be told to make adjustments to facilitate the 5seg for HLV use and not as a first stage for A1. I wonder exactly what would need to be altered in the current design? The throat? The vectoring? Any thoughts?

That has yet to be determined. It could be we stick with 4-segment, or we get a 4+dummy Ares I-X style for future requirements (doubtful), or yes it could go all the way to a 5-segment for a J-246 variant. Time will tell, but in any case ATK won't be hurting.

Ok, so I have a question for you. With 5 Seg doing so well in testing and HLV slated to be able to make great use of it and the timelines for development seem to match up very well, why wouldn't we go straight to 5 seg on a Block I HLV? Design it with 5 seg at inception for loads and ET attachment points...

jacqmans · « **Reply #82 on:** 08/31/2010 08:59 pm »

News Release Issued: August 31, 2010 12:42 PM EDT

ATK and NASA Successfully Test the Second Five-Segment Ares Development Motor (DM-2)

DM-2 Test Collected More Data than any Previous Solid Rocket Motor Test
Test Data Will Provide Valuable Information for the Development of Future Launch Vehicles

PROMONTORY, Utah, Aug. 31 /PRNewswire/ -- Alliant Techsystems (NYSE: ATK) and NASA conducted a successful ground test earlier today of the second Ares five-segment Development Motor (DM-2). The successful test is an important milestone in the development of America's next generation of launch vehicles.

Initial test data indicated that the motor, which was chilled to a 400 F core temperature since early July, performed as designed, producing approximately 3.6 million pounds of thrust, or 22 million horsepower, and burned for just over two minutes. The test collected 764 channels of data to accomplish 53 test objectives. This is the most data ATK has ever collected in a static fire test.

"The information collected from this test, used together with data from DM-1 and the Ares I-X flight test, will help further validate the five-segment design leading to critical design review next year," said Charlie Precourt, vice president and general manager, ATK Aerospace Systems, Space Launch Systems. "The data will also confirm the performance and reliability of this solid rocket, which can be configured for use on multiple launch vehicles."

The five-segment rocket was designed to maximize astronaut safety while providing the United States with an affordable and reliable launch capability for both crew and cargo missions. For example, a single five-segment solid rocket motor first stage, coupled with a liquid upper stage, would be able to lift more than 55,000 pounds of payload directly to Low Earth Orbit.

The main test objectives from today's static motor firing were measuring the first-stage rocket's performance at cold temperatures, and verifying the performance of new materials in the motor joints at the lowest range of operational temperatures.

"Testing at these extremes aids us in fully understanding all operating conditions for this motor," said Precourt, a former shuttle astronaut. "This data, along with information we have collected over the past three decades, confirms that this is the most powerful and reliable solid rocket motor ever designed, and it is the right motor to ensure the safety of our astronauts."

DM-2 is the largest human-rated solid rocket motor built today, measuring 12 feet in diameter and 154 feet in length. The five-segment motor is based on the design heritage of the flight-proven Solid Rocket Boosters on the Space Shuttle Program, and has been upgraded to incorporate modern technologies and materials. These include the addition of a fifth segment, changes to the propellant grain, a larger nozzle opening and upgraded insulation and liner.

The five-segment cases remain the same as those used for more than three decades on the Space Shuttle Program. Just like shuttle cases, the cases for this rocket are designed to be recovered and reused. This enables NASA and ATK to collect vital post-flight information and performance data, confirming a safe and robust design. The cases used in this ground test have collectively flown on 57 previous shuttle missions.

As the prime contractor, ATK continues to perform on schedule and on cost in support of NASA's space exploration programs. The next test for the program, Development Motor-3, will be a hot temperature test conducted next year.

ATK is a premier aerospace and defense company with more than 18,000 employees in 24 states, Puerto Rico and internationally, and revenues of approximately $4.8 billion. News and information can be found on the Internet at www.atk.com.

mkirk · « **Reply #83 on:** 08/31/2010 09:15 pm »

Quote from: psloss on 08/31/2010 02:41 pm

OK, maybe some better updates here:
http://twitter.com/MarkKirkman

Thanks for the mention Phil.

Some of us (actually most of us) were having serious internet/phone signal problems way out there in the middle of no-where with all those iPhones taking up bandwith - so twitter coverage was hard to execute today and not as timely or informative as I would have preferred.

Mark Kirkman

kermit · « **Reply #84 on:** 08/31/2010 10:36 pm »

the motor, which was chilled to a 400 F core temperature since early July

I think that should be 40 F

JosephB · « **Reply #85 on:** 09/01/2010 12:19 am »

Curious how they chilled it down?
Check it out.
http://www.nasa.gov/multimedia/videogallery/index.html?media_id=17916723

robertross · « **Reply #86 on:** 09/01/2010 01:29 am »

Quote from: rcoppola on 08/31/2010 07:38 pm

Quote from: robertross on 08/31/2010 07:30 pm
Quote from: rcoppola on 08/31/2010 06:19 pm
At some point very soon, ATK will be told to make adjustments to facilitate the 5seg for HLV use and not as a first stage for A1. I wonder exactly what would need to be altered in the current design? The throat? The vectoring? Any thoughts?

That has yet to be determined. It could be we stick with 4-segment, or we get a 4+dummy Ares I-X style for future requirements (doubtful), or yes it could go all the way to a 5-segment for a J-246 variant. Time will tell, but in any case ATK won't be hurting.

Ok, so I have a question for you. With 5 Seg doing so well in testing and HLV slated to be able to make great use of it and the timelines for development seem to match up very well, why wouldn't we go straight to 5 seg on a Block I HLV? Design it with 5 seg at inception for loads and ET attachment points...

1. It wouldn't be ready as quickly as a straight 4-segment

2. Unnecessary additional $M/flight

As stated on the Direct thread in the past, you really don't need that extra performance for some time to come. Keep everything as cheap as possible, especially at the beginning. The greater the per launch costs, the less you have to work with for other things.

But in the end it will be a political decison, from somwhere.

MP99 · « **Reply #87 on:** 09/01/2010 07:33 am »

There is also a large flight history for the 4-segs, which is good for an HR'd SD HLV.

cheers, Martin

TheFallen · « **Reply #88 on:** 09/01/2010 08:43 am »

Quote from: JosephB on 09/01/2010 12:19 am

Curious how they chilled it down?

Strong air conditioning units inside the hangar where the DM-2 motor was stacked and prepped for the test. ATK workers had to wear winter coats inside the building while the A/C units were activated. The air was cold enough that ice even formed along parts of the motor and the structure holding it.