Author Topic: Chances of Launches being Scrubbed?  (Read 3347 times)

Chances of Launches being Scrubbed?
« on: 10/31/2015 09:26 PM »
Hey guys, I'm the president of my model rocketry club and I was planning on doing a field trip to see a  rocket launch sometime between March to June. I've checked around and saw there  are some Atlas V launches and a Delta IV heavy launch around that time and I was wondering which will be a better choice. I know the Delta IV might be better since its bigger but my main concern is that it'll launch. So my question is which rocket has less chances of being scrubbed? I know the past 3 Atlas V launches have been fully successful without any delays or anything but I don't know of any before that. The Delta IV on the other hand I only actually followed one of them and that's when I went to see EFT-1 but i couldn't since it got scrubbed. I'm not sure if that was just something uncommon that has only happened a few times or if that happens all the time.

I know all rockets have a chance of being scrubbed, but I would prefer to go for the one with the least chances of it, so that the 4.5 hour drive to Kennedy wouldn't have been a waste of time (I wouldn't consider it that but most of the people in the club will).

Offline Steven Pietrobon

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Re: Chances of Launches being Scrubbed?
« Reply #1 on: 11/01/2015 12:07 AM »
I think Atlas V has a smaller chance of being scrubbed since the fuel of its first stage is kerosene compared to liquid hydrogen at -253 C for Delta-IV. The low temperature can cause many things to go wrong.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline vapour_nudge

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Re: Chances of Launches being Scrubbed?
« Reply #2 on: 11/01/2015 05:40 AM »
According to SFN, prior to yesterday's GPS launch, there were 25 consecutive Atlas 5s that were fuelled and launched on the first attempt, a string stretching back to 2012.

So I agree with Steven, Atlas is a good one to go with

Re: Chances of Launches being Scrubbed?
« Reply #3 on: 11/04/2015 02:14 AM »
According to SFN, prior to yesterday's GPS launch, there were 25 consecutive Atlas 5s that were fuelled and launched on the first attempt, a string stretching back to 2012.

So I agree with Steven, Atlas is a good one to go with

Ok Thanks for the info. That just convinced me on the Atlas. I didnt know they had so many without scrubs. Thanks for that.

Offline mdeep

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Re: Chances of Launches being Scrubbed?
« Reply #4 on: 11/24/2015 05:02 PM »
Which is not to be confused with delays! Also according to SFN, GPS 2F-11 moved at least three times, going from mid-September to the end of October. That's what will throw a wrench in your travel plans more than anything. A scrub is easy to plan for - just add an additional day. So I'm going to go the other way and say try for that Delta IV Heavy in May.*

* subject to change
Mike

Offline MarekCyzio

Re: Chances of Launches being Scrubbed?
« Reply #5 on: 11/24/2015 05:53 PM »
I know all rockets have a chance of being scrubbed, but I would prefer to go for the one with the least chances of it, so that the 4.5 hour drive to Kennedy wouldn't have been a waste of time (I wouldn't consider it that but most of the people in the club will).

1. Choose Atlas V
2. Pick a launch that has a large window
3. Keep your fingers crossed
4. Be prepared to stay overnight


Offline c3infinity

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Re: Chances of Launches being Scrubbed?
« Reply #6 on: 11/24/2015 07:25 PM »
I know all rockets have a chance of being scrubbed, but I would prefer to go for the one with the least chances of it, so that the 4.5 hour drive to Kennedy wouldn't have been a waste of time (I wouldn't consider it that but most of the people in the club will).

1. Choose Atlas V
2. Pick a launch that has a large window
3. Keep your fingers crossed
4. Be prepared to stay overnight

A futher note on item 1. An Atlas V 401 configuration (no solid boosters) will have the best chance for being green on any given day's high-altitude winds.

Offline mheney

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Re: Chances of Launches being Scrubbed?
« Reply #7 on: 11/24/2015 07:48 PM »
The other thing to watch (obviously) is the weather.  I've done road trips from Ann Arbor (STS-4, STS-41D, STS-29)
and Washington, DC (STS-50 (on my honeymoon!) and STS-135) to watch launches; late scrubs are usually weather, not hardware.  I turned around once in central Kentucky at 3 am when one mission had a computer issue that caused a one week delay....  With only a 4.5 hour drive, you'll have a bit more flexibility on making a go/no-go decision on whether to head for the launch or not.

Offline MarekCyzio

Re: Chances of Launches being Scrubbed?
« Reply #8 on: 11/24/2015 08:07 PM »
For some rockets (such as Atlas V), most of the scrubs are related to external causes (weather, stupid boaters). For others, it is a mix of external causes, rocket causes and launch pad causes (SpaceX hellium leaks, Space Shuttle hydrogen leaks, Delta IV hydrogen valves, LC-41 water valves and so on). So picking Atlas V gives you the best chance of seeing a launch. Picking Atlas V with daytime launch also gets you the best viewing positon (Playalinda Beach).


Offline xcel102

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Re: Chances of Launches being Scrubbed?
« Reply #9 on: 11/25/2015 07:11 AM »
Picking Atlas V with daytime launch also gets you the best viewing positon (Playalinda Beach).
Marek, how far is Playalinda Beach from the Atlas V pad?

I've always wondered which active launch pad allows the closest public viewing (both for free and with ticket). I haven't seen any launch in Florida; here in California the closest I've seen is Atlas V, 3 miles from SLC-3E (although the hills block the bottom so moment of ignition cannot be seen). Is there another pad in either Vandenberg or Cape that will allow me to get even closer (either free or with ticket)?

Offline MarekCyzio

Re: Chances of Launches being Scrubbed?
« Reply #10 on: 11/25/2015 12:04 PM »
Playalinda is about 5 miles from the launch pad. Great, unobstructed views. My favorite spot for Atlas V.

The best paid place to watch Atlas V launch is LC-39 Gantry - 2.2 miles from the pad. $45 + KSC ticket (around $100 total). KSC offers it from time to time, it sells out fast (only 400 or so tickets). KSC also offers Saturn V Building lawn viewing - 5.5 miles. Not recommended - Playalinda is much closer for day launches and night launches are beter viewed from some distance - my favorite spots are Cape Canaveral beach for things going to GEO and Titusville Max Brewer bridge for things going to ISS.

Offline laika_fr

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Re: Chances of Launches being Scrubbed?
« Reply #11 on: 11/25/2015 01:08 PM »
nice waves in Florida  8)

Considering the atmosphere is a bit unstable, the forecast can't be carved in stone.
But the overall weather is not bad.

Current risks for the upcoming Atlas V flight would be :

- surface wind (moderate/intermediate)
- upper level wind (moderate)
- thick clouds (moderate)

I don't live in FL nor i'am a meteorologist, but monitoring the weather in this peculiar area became sort of a hobby. >:D
a shrubbery on Mars

Offline Sam Ho

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Re: Chances of Launches being Scrubbed?
« Reply #12 on: 11/25/2015 05:34 PM »
Refer also to the following thread, which is mostly restaurant reviews for the area, if you plan to watch a launch.

http://forum.nasaspaceflight.com/index.php?topic=18970.0

Offline laika_fr

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Re: Chances of Launches being Scrubbed?
« Reply #13 on: 11/27/2015 01:34 AM »
update

Current risks for the upcoming Atlas V flight (dec 3) :

- upper level wind (intermediate)
- surface wind (moderate)
- thick clouds (moderate)
a shrubbery on Mars

Tags: Atlas V Delta IV