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#200
by
ugordan
on 31 Jul, 2011 22:22
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Messenger orbits that Sun at ~48 km/s, simply by virtue of being in orbit around Mercury.
One can take this to silly proportions and measure that speed relative to Earth instead. Depending on where Mercury and Earth are in their orbits, that relative speed can approach 90 km/s. This is why I'm not a big fan of these "fastest ever" games. A snail's pace in one system can be Ludicrous Speed (TM) in another frame of reference.
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#201
by
Rocket Guy
on 31 Jul, 2011 23:16
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No, as stated above, the Helios probes hold the record with a relative velocity [to the sun] around 160,000 mph.
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#202
by
Jim
on 31 Jul, 2011 23:18
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From the NASA tweetup agenda, Thursday we'll go on a tour of KSC and CCAFS, including the Atlas V Spaceflight Operations Center and Launch Complex 41. Where exactly is the former?
I will be in the ASOC every day until launch
Any live web cam feed we could watch you work?
Nope, I will be in a small support room
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#203
by
Rocket Guy
on 31 Jul, 2011 23:18
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http://www.nps.gov/cana/planyourvisit/park-closure-notices.htm
That page will be updated with any closure notice usually about 3 or 4 days before they close. Shuttle launches they closed about 3 days prior to launch, but I don't think they do that with the unmanned. Honestly haven't watched it close enough to be sure.
That page frequently lacks info for anything but the shuttle. The people who run the place tend not to even know there is a launch ("what launch?" the day before). In the past Playalinda has, for whatever reason (examples include MRO and NRO L-30 in June 2007), been closed last minute by security despite them saying they aren't closing. Those along with New Horizons are the only closures I recall for Atlas V, though I have not checked every time.
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#204
by
Antares
on 31 Jul, 2011 23:39
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NASA doesn't determine whether an area is open for launch or not. Air Force Range Safety does.
On the fastest object debate, recall that Pluto had a Star 48 on it too. This one is just the Centaur.
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#205
by
just-nick
on 01 Aug, 2011 19:11
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The New Horizons Atlas 551 did some pretty fancy throttle work, ducking power down during the SRM burn to delay max-q, up again to maintain control requirements, etc. Then the standard 2.5g and 5.0g segments (are those closed loop?).
Anyway, any info if the Juno launch will do similar early throttling? The press kit mentions the 2.5g and 5.0g segments.
--Nick
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#206
by
ugordan
on 01 Aug, 2011 19:16
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Anyway, any info if the Juno launch will do similar early throttling?
I would assume so. The vehicle configurations are the same. That thing will jump off the pad faster than you can say "liftoff" so early throttling for max-q reasons is likely.
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#207
by
just-nick
on 01 Aug, 2011 19:22
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Anyway, any info if the Juno launch will do similar early throttling?
I would assume so. The vehicle configurations are the same. That thing will jump off the pad faster than you can say "liftoff" so early throttling for max-q reasons is likely.
NH was just beautiful to watch come off the pad...
This thing should be *slightly* faster - without the Star 48, it is just a little bit lighter.
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#208
by
ugordan
on 01 Aug, 2011 19:45
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This thing should be *slightly* faster - without the Star 48, it is just a little bit lighter.
Not quite, NH was a very light spacecraft, while Juno is not. In any case, payload mass is indistinquishable in the initial acceleration profile as it makes up only a fraction of GLOW.
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#209
by
Jim
on 01 Aug, 2011 20:51
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This thing should be *slightly* faster - without the Star 48, it is just a little bit lighter.
Not quite, NH was a very light spacecraft, while Juno is not. In any case, payload mass is indistinquishable in the initial acceleration profile as it makes up only a fraction of GLOW.
The PNH payload included the STAR-48 and spin table.
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#210
by
ugordan
on 01 Aug, 2011 20:57
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What was the total mass of that setup?
NH itself is under 500 kg and Juno is over 3600 kg.
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#211
by
Ben the Space Brit
on 01 Aug, 2011 21:00
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What was the total mass of that setup?
NH itself is under 500 kg and Juno is over 3600 kg.
I'm sure a lot of the difference is down to the differing delta-v requirements for Pluto (which much further away and is also out-of-plane) and Jupiter.
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#212
by
ugordan
on 01 Aug, 2011 21:01
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I'm sure a lot of the difference is down to the differing delta-v requirements for Pluto (which much further away and is also out-of-plane) and Jupiter.
I understand all that, I was addressing the point Juno is lighter since it doesn't have a Star 48. My point was even with the kick stage, the NH setup could still be lighter than Juno.
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#213
by
Jim
on 01 Aug, 2011 21:02
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Star-48 is about 5000 lbs.
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#214
by
ugordan
on 01 Aug, 2011 21:04
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I got that, so the spin table would need to be a tonne to match Juno's payload system weight. Doesn't strike me as likely.
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#215
by
just-nick
on 01 Aug, 2011 21:54
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There is also the fairing - Juno is flying with the short fairing (3,524kg per the user's guide) and I think NH used the medium (4,003kg).
I suspect it'll all come out to a wash - or near enough as to make no difference to the naked eye.
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#216
by
Comga
on 01 Aug, 2011 22:37
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Anyway, any info if the Juno launch will do similar early throttling?
I would assume so. The vehicle configurations are the same. That thing will jump off the pad faster than you can say "liftoff" so early throttling for max-q reasons is likely.
NH was just beautiful to watch come off the pad...
(snip)
That it was!
My advice: Don't blink! Pray for clear skies.
And don't take photos, unless that is your main goal. Buy professional ones and enjoy the very, very brief time you can see the rocket flying. It will move like the proverbial bat-out-of-Hell.
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#217
by
yinzer
on 01 Aug, 2011 22:42
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People, think about this. The Atlas V core booster holds over 250,000 kg of propellant. Each SRB weighs nearly 47,000 kg. A difference of 1,000 kg in payload out of a 500,000 kg in gross weight is going to be completely invisible.
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#218
by
Chris Bergin
on 02 Aug, 2011 01:54
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ULA:
L-4:
All launch preparations are progressing well in support of the Atlas V Juno launch set for Friday, August 5 for NASA. The launch window opens at 11:34 a.m. EDT and extends until 12:43 p.m. The L-4 forecast shows a 70 percent chance of favorable weather for launch.
Mission Booklet:
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#219
by
lsullivan411
on 02 Aug, 2011 02:32
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Just an FYI for people going to the launch -- putting this here as we don't get the viewing/going to threads for these launches (at least not yet!).
Informal get together for anyone coming for the launch in Titusville. Chris Gebhardt and I will be at Dogs R Us -- it's a sports bar/restaurant on Rte. 1, Thursday evening
We should be there from about 6:30 Thursday night for a couple hours anyway. Don't want to tie up this thread with a lot of posts for this, so PM me for any directions or info you need. Food is pretty decent, and beer is pretty cheap as it goes these days. Hope to see you there!