LIVE: Delta II - GRAIL - September 10, 2011

[TJL]

I remember Delta 178 too. Lisa Malone - who was with us at the press site today since she heads KSC Public Affairs - did the launch commentary for the GOES-G mission. Definitely not the best thing to have happen on NASA's first post-Challenger launch.

I too remember the launch failure of Delta 178.
Ironically, we were driving back from Washington, D.C. after attending the funeral that morning for Challenger pilot Michael Smith, when it came over the radio.

[TJL]

This being the last (scheduled) Delta 2 launch from LC-17, I thought this link may be interesting.
It actually includes photos of every Delta (except Delta 4) launch to date...enjoy!

http://kevinforsyth.net/delta/

[robertross]

I've got a few shots from our remote camera which we had located to the southeast of the launch pad on the perimeter of the concrete apron. I'm not sure why Mike edited them rather dark, but the Sun's shadow was pretty much directly in front of the rocket, above, at launch time.

Sharing is caring, so I hope you enjoy!

Matt
http://www.aresinstitute.org

Fantastic images, all around. Thanks so much for sharing!

[jacqmans]

STATUS REPORT: ELV-091211

EXPENDABLE LAUNCH VEHICLE STATUS REPORT

Spacecraft: GRAIL (Gravity Recovery and Interior Laboratory)
Launch Vehicle: Delta II 7920 Heavy
Launch Site:  Cape Canaveral Air Force Station, Fla.
Launch Pad:  Space Launch Complex 17B
Launch Date:  Sept. 10, 2011


Atop the Delta II rocket, GRAIL was launched successfully from Pad 17B
on Sept. 10 at 9:08:52 a.m. After GRAIL-A and GRAIL-B separated from
the Delta II's second stage, the Deep Space Network's Goldstone
tracking station acquired them as planned. It verified that solar
arrays were deployed and both GRAIL spacecraft were operating
normally.

GRAIL's primary science objectives are to determine the structure of
the lunar interior, from crust to core, and to advance understanding
of the thermal evolution of the moon.

[jsmjr]

I wondered about the way the exhaust plume swept up over the vehicle on the pad at launch (per Chris B's screen cap attached).  Seemed off-nominal.  But here's a twitter-sourced explanation:

@ottaross: @NASA_LSP Question: were #GRAIL pre-liftoff launch moments nominal? There seemed to be excessive exhaust accumulation around the vehicle.

@ottaross: @NASA_LSP ... Would have thought this was failure of sys that clears exhaust. Smoke, hot gases not a risk to vehicle? http://t.co/W3EtECs

@nasa_lsp: @ottaross Thanks for the Q. I'm waiting on a technical response from our engineer. Hope to give you a better answer than what I know

@nasa_lsp: @ottaross exhaust was due to pad design & ducting/water suppressant system on 17B & DIIH uses 46" GEMS vs. 40". Everything is nominal

Now, can someone interpret the answer for me?

[Jim]

It is standard for that pad.  The larger GEMs cause it.

[edkyle99]

I wondered about the way the exhaust plume swept up over the vehicle on the pad at launch (per Chris B's screen cap attached).  Seemed off-nominal.  But here's a twitter-sourced explanation:

@ottaross: @NASA_LSP Question: were #GRAIL pre-liftoff launch moments nominal? There seemed to be excessive exhaust accumulation around the vehicle.

@ottaross: @NASA_LSP ... Would have thought this was failure of sys that clears exhaust. Smoke, hot gases not a risk to vehicle? http://t.co/W3EtECs

@nasa_lsp: @ottaross Thanks for the Q. I'm waiting on a technical response from our engineer. Hope to give you a better answer than what I know

@nasa_lsp: @ottaross exhaust was due to pad design & ducting/water suppressant system on 17B & DIIH uses 46" GEMS vs. 40". Everything is nominal

Now, can someone interpret the answer for me?

The attached image provides part of the answer.  Look closely and you'll see several important details.  Two angled exhaust ducts that were added to SLC 17B to handle the GEM-46 exhaust plumes (for Delta 3 originally) are visible (with rollaway sections that allow the mobile service tower to roll up to the vehicle.  A vent covered with louvers is visible on the downrange (away from the mobile tower) side of the vehicle (in the case Delta 323 from 2007).  This vent was added, as I recall, to prevent RS-27A flames from being sucked back toward the vehicle when the SRMs ignited (but I may be mis-remembering this).  It could be that they were added merely to vent exhaust from the two downrange ground-lit SRMs.  Now, when the SRMs ignite, some of their gases escape from the vent, rising to embrace the rocket as it starts to rise.  Launches from SLC 17A - and SLC 2W at Vandenberg AFB - don't produce this effect.

 - Ed Kyle

[Prober]

Noticed @ T-4.0 that a scramble looked like it took or takes place.

Talking about the Lox area.  Noticed that (if memory serves) they were like at 79 % filled?   Anyhow, at the count you could hear the updates to get Lox up to full.

From a viewr POV it looked like the LoX just made the time with a couple of secs to spare.

[Liryc]

The attached image provides part of the answer.  Look closely and you'll see several important details.  Two angled exhaust ducts that were added to SLC 17B to handle the GEM-46 exhaust plumes (for Delta 3 originally) are visible (with rollaway sections that allow the mobile service tower to roll up to the vehicle.  A vent covered with louvers is visible on the downrange (away from the mobile tower) side of the vehicle (in the case Delta 323 from 2007).  This vent was added, as I recall, to prevent RS-27A flames from being sucked back toward the vehicle when the SRMs ignited (but I may be mis-remembering this).  It could be that they were added merely to vent exhaust from the two downrange ground-lit SRMs.  Now, when the SRMs ignite, some of their gases escape from the vent, rising to embrace the rocket as it starts to rise.  Launches from SLC 17A - and SLC 2W at Vandenberg AFB - don't produce this effect.

 - Ed Kyle

Thanks for your inputs !
These exhaust ducts look very impressive.
Is the main duct completely "flat" or is it going deep under the Delta 2 rocket and then coming back to the ground surface towards the exit ?

And I was also wondering how were made the lateral ducts...
On the first image attached we can clearly see that the fixed part of the lateral duct is "closed" towards the rocket but open on the sides. Looks like concrete or something, but not a door.

On the 2nd image, though, it is clear that the lateral part has been closed to open the duct and let the exhaust flow.
Here, it looks more like doors.. but with the temperature of the GEM plume i'm quite surprised that a door could be sufficient.

+ we don't really see doors on the other pictures, I can imagine them installing doors for each flight, but it seems quite constrainful what do you think ?

[Jim]

The doors swing inward and close off the duct at both openings.  The exhaust isn't that hot and it is for a short duration.

Look at the other pad and you will see the main duct is missing.  The trench does not go much past ground level.

[Liryc]

Yeah I saw that the 17A was much lighter and didn't have the lateral ducts.
Do they have a water deluge like on many launchers ? (to cool down the exhaust and noise ?)

[Jim]

Yeah I saw that the 17A was much lighter and didn't have the lateral ducts.
Do they have a water deluge like on many launchers ? (to cool down the exhaust and noise ?)

A little.  The ducts were added to B for the noise of the 46" SRMs.  Water is only for cooling

[Liryc]

Oh, ok I see.
I was trying to see where is the water thrown.. but it might be well hidden into the duct...