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Darasen
2005-Feb-08, 02:08 PM
I was lookind at APOD today and wondered if anyone here had any input on todays image. I am sure the woo woo-s are salivating.
http://antwrp.gsfc.nasa.gov/apod/image/0502/HLmystery_nsl.gif

Doodler
2005-Feb-08, 02:11 PM
I was lookind at APOD today and wondered if anyone here had any input on todays image. I am sure the woo woo-s are salivating.
http://antwrp.gsfc.nasa.gov/apod/image/0502/HLmystery_nsl.gif

Asteroid?

Wally
2005-Feb-08, 03:23 PM
Iridium flare perhaps? (granted, it appears to be a pretty long lasting one, but I think if you're in the right spot, they can last several seconds. . .).

sarongsong
2005-Feb-08, 03:42 PM
Maui's sun snare (http://maui.aloha-hawaii.com/hawaii/haleakala/). 8)

Iris
2005-Feb-08, 04:07 PM
They ARE salivating! You should see a couple posts in the forums the APOD tell the people to discuss into! :wink:

Either way, what else than a very close missed asteroid could this be? I never saw an iridium flare lasting several minutes like that!

Still, it's so bright...

Grand Vizier
2005-Feb-08, 04:28 PM
Well, if it's an Earth orbiter, Iridium or whatever, it should be possible to calculate its orbital inclination from that path at that latitude. (The west-east motion is actually consistent with a regular prograde orbit). Then perhaps candidates might pop up by comparison with databases. After that, the angular velocity should help to finger the correct one.

But if no candidates fit, then who knows? There have been cases (detected on radar) of meteors skipping off the top of the atmosphere. Maybe we've got a 'flat stone on a pond' phenomenon here :wink:

Argos
2005-Feb-08, 04:46 PM
Edited as bellow

Argos
2005-Feb-08, 04:47 PM
Well, if it's an Earth orbiter, Iridium or whatever, it should be possible to calculate its orbital inclination from that path at that latitude. (The west-east motion is actually consistent with a regular prograde orbit).

Yes, it actually looks like something thatīs been launched from Cape Canaveral.

Weird Dave
2005-Feb-08, 04:57 PM
An unidentified satellite-like object could well be a spy satellite, I suppose.

8-[
:-$

Maddad
2005-Feb-08, 05:40 PM
We don't know what the streak was on December 17, 2004. Two different Hawaiian continuously updating web cameras recorded it, one at Haleakala and the other at Mauna Kea. It's not a satellite either because there's no record of it at http://www.heavens-above.com/

The woo-woos are out in force. This particular APOD is overloading the NASA server.

peedeejones
2005-Feb-08, 05:46 PM
This "object" was recorded back in December.
Did it hit us? Were we invaded? Were we zapped?
No? Then I am ging back to bed.
Wake me when the E.T. gets here.

A Thousand Pardons
2005-Feb-08, 05:50 PM
Iridium flare perhaps? (granted, it appears to be a pretty long lasting one, but I think if you're in the right spot, they can last several seconds. . .).
Do I read that right, the notes in the corner, that it lasted for twenty minutes at least? If so, Iridiums don't last that long. Asteroids neither.

We don't know what the streak was on December 17, 2004. Two different Hawaiian continuously updating web cameras recorded it, one at Haleakala and the other at Mauna Kea. It's not a satellite either because there's no record of it at http://www.heavens-above.com/
As Weird Dave said, it could be a spy satellite. I don't think there are any records of those at Heavens Above. It would have to be fairly high to have such a slow orbit--and bright.

Doodler
2005-Feb-08, 05:59 PM
If its an intelligence bird, there are people at the NRO doing alkaseltzer cocktails. Especially if the information posted from those two observatories is enough to work out a basic orbital track.

A Thousand Pardons
2005-Feb-08, 06:04 PM
Especially if the information posted from those two observatories is enough to work out a basic orbital track.
they'd just put it somewhere else :)

still, it seems pretty bright. I bet it turns out to be a helicopter

peedeejones
2005-Feb-08, 06:11 PM
Whatever it is, I'm sure The History Channel is working on an investigative program to air any day now.

Were any cows found mutilated in Hawaii after the streak was seen?

Grand Vizier
2005-Feb-08, 06:17 PM
I've been reading through the APOD bulletin board and I thought the most convincing story seemed to be that it was fuel dumping from the Centaur stage of the Atlas booster that launched the AMC-16 comsat to GTO (Cape Canaveral, 17 Dec, 12:07 UT).

One observer reports that he personally observed the phenomenon and that stars were faintly visible through it, which is consistent with it being a series of dissipating gas clouds. But, as I said, it should be possible to pin this down with a bit of maths - for those who are better at it than me, of course :)

[Edited to add...]

Reinforced by a quick Google:

Centaur fuel dump (http://www.google.co.uk/search?hl=en&safe=off&c2coff=1&q=centaur+fuel+dump &btnG=Search&meta=)

Check some of the images - looks convincing to me.

Argos
2005-Feb-08, 06:28 PM
The sequence spans almost 20 minutes. A copter should go faster, shouldnīt it?

Doodler
2005-Feb-08, 06:29 PM
Especially if the information posted from those two observatories is enough to work out a basic orbital track.
they'd just put it somewhere else :)


True, but that's not something they like to do unless there's a mission critical reason for it. Whats worse, if whomever wants to know where it is works out enough to keep a long eye on it, you really can't hide it, the changes can be tracked.

Anyway, hopefully it wasn't, the NRO goes through enough heck just putting the things up in some semblance of silence that I empathize with them when these things are compromised, even accidentally.

eburacum45
2005-Feb-08, 06:45 PM
Yes, the APOD board discussion suggests it was a fuel dump of some sort. The speed of the object (very slow) and the height (roughly derived by triangulation to be about 1000 km) suggest is was not a solid object, rather a spherical cloud of gas emitted from a rocket going to geosynchronous orbit.

A Thousand Pardons
2005-Feb-08, 08:51 PM
The sequence spans almost 20 minutes. A copter should go faster, shouldnīt it?
They can hover. :)

That's why I mentioned copters, but I see that the mystery has probably been solved, as a fuel dump.

JustAGuy
2005-Feb-08, 09:28 PM
Wow. The discussion going on on the BB linked from APOD is a great example of why allowing anonymous posting on a BB is a bad idea...

sarongsong
2005-Feb-09, 02:34 AM
Tue 02.08 (http://www.coasttocoastam.com/)
"First Hour: Planetary scientist David Grinspoon and astronomer Seth Shostak of SETI will discuss the strange streak seen over Hawaii..."

Grand Vizier
2005-Feb-09, 02:54 AM
Curiously, by the way, everyone on the APOD board - even those proposing the fuel dump scenario - is referring to the AMC-16 launch as taking place on Dec 16. It didn't. From Jonathan McDowell's space report (http://www.planet4589.org/jsr.html)...



The SES Americom AMC 16 satellite was launched on Dec 17. AMC 16 is
a Lockheed Martin A2100AX hybrid Ku-band/Ka-band communications satellite
which will provide television broadcast services to North America.

AMC 16 was launched by AV-005, the fourth Atlas 5 mission to be launched.
The Atlas 521 rocket has two solid rocket boosters, the Atlas 5 core stage,
and a single-engine Centaur second stage with a 5-meter fairing.

The first Centaur burn put the vehicle in a 166 x 5239 km x 27.2 deg
parking orbit, followed by a second burn to a 4761 x 34611 km x 18.2 deg
transfer orbit. AMC 16 separated at 1355 UTC and will use its own
propulsion to reach its final orbit.


Note the Centaur stage separation timing. This is hugely consistent with the phenomenon being a fuel dump, but a Dec 16 launch wouldn't hack it at all.

vonmazur
2005-Feb-15, 05:41 PM
Thanks for the posts, I can sleep tight tonight, and not worry about aliens coming to Hawaii, and mutilating cattle or tourists....I figured the woo woo crowd would go nuts with this, and they did....

Dale in Ala

dgavin
2005-Feb-15, 08:34 PM
Well I've looked and a looked at it and have a few facts.

1. Object was not present in prior frames. Consitant with a metorite but not a satalitie.

2. Due to the timed 180sec exposures, the object appears to decelerate. Consitant with a meteorite in atmosphere, not with a satilite or fuel ejecta in space.

3. Object gets brighter as it decelerates. This might be consitant with a object breaking apart in atmosphere, but is not really consitant with meteroites or salilites.

Possiblly a chuck of ice (comet) that's hit atmosphere heating and turning to gas?

eburacum45
2005-Feb-15, 09:56 PM
I'm completely satified by the Centaur explanation; for a very good reason- it is the right one.
This was a fuel dump in Geosynchronous transfer orbit- in which the rocket concerned is climbing rapidly away from Earth.
That is the reason for the apparent slow down (which you are correct in identifying).

dgavin
2005-Feb-16, 02:02 AM
AMC 16 separated at 1355 UTC and will use its own
propulsion to reach its final orbit.

The Picutre Frame starts at 14:19 UTC and continues through 14:39 UTC.

It's possible it was a rocket or a fuel dump. But there are issues with that, the fuel dump lasted 20 minutes? From what i know -no- rockets carry that so much extra fuel it would take 20 minutes to dump it, additionally just the act of dumping fuel in space would either cause acceleration or slight changes in direction.

For the most part these are caculated so that there is only enough extra fuel for slight corrections to direction or orbits. And you don't dump the fuel because you can never be sure when a minor chage could be called for.

I think it's the burn up of the stage it seperated from, 14 minutes is about right timing for that to be pulled back by gravity into our atmosphere. As it would break up in rentry, it would appear to grow larger as it slowed down too. Nasa has provided examples of that happening before, .... I think we all saw that last one that grounded space flight for a while...

Wally
2005-Feb-16, 03:02 PM
[It's possible it was a rocket or a fuel dump. But there are issues with that, the fuel dump lasted 20 minutes? From what i know -no- rockets carry that so much extra fuel it would take 20 minutes to dump it, additionally just the act of dumping fuel in space would either cause acceleration or slight changes in direction.



The cloud itself lasted that long, not the dumping process (which probably only takes several seconds to a minute or 2).