Dam, nprev how badly did it scare you?, did you crap your pants or take it with a more “Well no need to commit suicide now, the bomb going to do it for me” kind of stride?

By the way how do you know what’s in Stardust flight path… if that info in a link you provided already, sorry I’m lazy.

It was something else. I was in Butte, MT at the time, nine years old. My younger brother & I were walking home in the early afternoon, and we heard this LOUD double sonic boom; shook the whole city. We looked up, and here's this white teardrop of a fireball hauling across the sky towards the north and leaving a long trail. My brother asked me what it was, and all I could think was that it was an incoming missile. So, we ran home & hid in the basement!

As it turns out, we weren't the only ones that thought that. NORAD originally interpreted it as a probable launch from a hostile submarine due to its odd vector (and the fact that it was heading pretty near Malmstrom AFB, MT), and began running the EWO (emergency war order) process...brrr. I think that event marked when NORAD got serious about tracking large meteors...

I also wonder what that would have rated on the Torino scale. If I remember correctly, the object was estimated to be around 100m in diameter, and the relative velocity was around 20 miles per second. Its closest approach was 35 miles above the Montana/Idaho border before it skipped back out of the atmosphere again.

So, I guess I can claim the dubious honor of being one of the few living people almost killed by an asteroid (or comet?) impact! 35 miles is a pretty close miss...

----

On a different note, as far as those targets I mentioned...I'm just talkin', I don't know if they're feasible or not. However, it looks like 3200 Phaethon probably won't work; its perihelion is well inside Mercury's orbit, and the aphelion is beyond Mars...sounds like too much differential velocity for an effective flyby, even if the geometry turned out to be favorable.

The article on Space.com about a capsule return abort contingency, where the spacecraft would divert with the capsule and return in 3 or 3 1/2 years for another try suggests that Stardust may be close to a "free return" trajectory, much the same as was planned for Contour.

Basically, they have 2 options: Flyby of something within the post-swingby trajectory cone available using most of their propellant, whatever the best available target is, or put the vehicle on the Earth-swingby trajectory, and use the swingby to provide a much larger trajectory change and put it on a course to something more specifically interesting.

Regarding the 1972 fireball. I was in Yellowstone at the time with a brother and 2 friends on "the Great 1972 Western Trip".... a 20'ish day loop-vacation trip around the western US. No I <expletive deleted> didn't see the <expletive deleted> fireball. We were driving around Yellowstone making foul comments about tourists who'd cause "bear jams" by stopping in the middle of the road to take pictures and dodging spatter-showers. We heard about it the next day and made the appropriate comments of total frustration.

Oh.. and I'd be quite surprised if the fireball was at all associated with a comet. That thing was undergoing significant ram-pressure force (it did make big sonic booms), and probably had to have had the mechanical strength of rock, at least.

There NEVER has been a meteor shower fireball that's reached low enough altitude to make sonic booms, and *** NEVER *** been one that dropped a meteorite.

A basic description of meteor material somebody made maybe 2 decades ago, and which holds up today, is that they have all the mechanical strength of cigarette ash. Small Kuiper-belt objects are probably giant cosmic dust-bunnies, loosely packed together, but ultimately made of clots and clumps of aggregates of sub-micrometer dust. Bigger ones in the many of kilometers size range may have had enough radio-isotope heat to melt or sinter ices and turn into a hard block of dirt-ice inside, but we've had little evidence anything we see as comets have had that much thermal processing.

Zdenek Sekaninana <sp?> some 15 years ago analyzed the Tunguska fireball's parent body's entry path and mechanical forces acting on it. The entry angle below the horizon is poorly constrained... some Zero to 15 degrees, which doesn't help modeling, but the object disintegrated and did it's airburst when it was being subjected to a ram-pressure enough to crush softish rock, plus-or-minus some amount. It was probably (if I remember right) stronger than the crumbly varieties of carbonaceous chondrite, but much softer than nickle-iron. Maybe an ordinary chondrite, maybe a less metamorphosed one.

I'm all for a all out Ceres flyby!



* Looks around room at Disbelief stares*

Well since we are all dreaming, and this craft seems to have acquired some amazing capabilities, I'd prefer a flyby of Alpha Centauri. I'd also like a peek at the mass at the galactic center.

In Ithaca, NY, where Carl Sagan once lived and worked, there is an educational memorial to the man called the Sagan Planet Walk. The Sol system is scaled down to one mile, with informational monuments depicting the main worlds from our Sun to Pluto (the number of moons data is already terribly out of date for the Jovian planets).

The nearest star, Alpha Centauri (actually Proxima Centauri), would need a representative monument in Hawaii. And that is the nearest star to Sol.

http://sciencenter.org//saganpw/

Realistically..... they'll look at the current spacecraft trajectory, and run forward to see what encounters are possible given the available dV and/or future flyby trajectory adjustments using Earth, and the power situation given how carefully they had to manage the spacecraft when it was out at aphelion.

It'll be a case of what can we visit with Stardust, not can we visit XXX with Stardust. Potential candidates will select themselves based on the orbital mechanics of it all.

Doug

I saw something about the 1972 fireball having a close orbital similarity to Encke in Sky & Telescope a long, long time ago...that info might have since been superseded. Still, if this is accurate, couldn't it have been a stony or iron/nickel mass that had been blown clear of the comet's nucleus by outgassing at some time? I'm not sure that we understand the structure of cometary nuclei well enough at this point to rule that out, or even to apply a "one-size-fits-all" standard to them as a class. Lots of variety observed in the nuclei we've examined to date...

Also, the diameter estimates for the object are in the 5-10m range now, not 100m as I originally wrote. Getting old now, so of course I exaggerate!

Sorry that you missed it, Ed...I just wish that I'd understood what it was at the time well enough to stay outside & watch it as long as I could!

Actually, I just missed a small amount of feasible viewing; it was almost right at zenith when I heard the boom & looked up, and it was moving...it was probably over the northern horizon in less than twenty seconds.

We really *don't* understand the structure of comet nucleii, but our best understanding is that the normal comet nucleus never really heated up inside enough to melt water ice, and the gravity is so low that they are "underdense" objects with a very high porosity level.

Indications of this is the fluffy-aggregate-of-submicrometer-grains nature of what we believe to be comet dust collected in the upper atmosphere, the ability of nucleii to totally dissipate into dust clouds, the mass (and with diameters roughly known, the density) of comets inferred from their orbital changes due to "non-gravitational-forces", and the lack of evidence for any meteorites or high-density metoroids from comet-associated meteor schowers. Hardly "rock-solid" evidence, but all pointing in the same direction.

That may totally not apply to mega-comets in the form of 100 or 200 or 500+ kilometer KB objects, or fragments of any formed by collissions. I have no idea what the modelling currently indicates is a size where Kb objects will squeese the porosity out of their cores, where they'll sinter cores into solid low-temperature ices plus water-ice and dust "cryo-rock", where the water itself will sinter solid, with low density ices driven out, where water will melt, or where in even larger objects you might get water driven entirely out of cores.

Add questions on the role of Aluminum-26 and other short-lived isotopes in heating small bodies like asteroids, and questions on the time scale of asteroid accretion vs KB object accretion... I don't know where the models have gotten to and what could be a minor part of the Earth-intersecting population from the outer solar system. But, so far, comet stuff seems to have all the "guts" of freeze-dried ice-cream.

Interesting that your description of a comet compares it to ice cream:

"In honor and anticipation of humanity's first direct contact with a comet, folks at the nearby Cornell Dairy Bar created something special called Cornell Comet Swirl. A large poster in the room described this as a combination of "kaluha ice cream, dark fudge swirls, and swirls of creamy caramel and pecans."

"The poster continued that this confection "represent[ed] the fusion and cosmic swirling of a myriad of components," just like how scientists think comets are made up of a preserved celestial mix of ice, rock and complex organic molecules formed during the early days of our Solar System's creation. Comets may even have played an important role in the formation of Earth's atmosphere, oceans and life. This is why scientists wanted to sample a comet, to discover what was going on in our cosmic neighborhood five billion years ago."

http://www.zwire.com/site/news.cfm?newsid=...id=216620&rfi=6

An interesting review on Universe Today:

http://www.universetoday.com/am/publish/bo...rse.html?912006

I've always had a soft spot for Fred Hoyle (and Tommy Gold). They may have been wrong more often than they were right, but they were both *interesting*!

Oh, and some of Hoyle's theories *were* accepted, so when can we gather round to watch a certain broom stick's Star Trek moment ('To boldly go, where...')?


Bob Shaw

I prefer to call this the currently, generally accepted theory. The results from Deep Impact suggesting clays and carbonates in Tempel 1 haven't been published yet, but this is consistent with the aqueous minerals seen in carbonaceous meteorites.
This implies comets did undergo sufficient heating to form liquid water.


- Bob Clark

Anyone seen any images other than the two nasa-tv caps of the capsule since they opened it out. I'm a bit disapointed that we've not had any new pics etc.

There's a press conf scheduled for 1900 UT tomorrow, but that will clash with NH launch.

Doug

Bob Shaw,

Sure Fred Hoyle theories are intrusting... but that was about it. Basically he lacked a major understanding of evolution and biochemistry, I can go into detail but don’t have the time now. Also I was thinking of Fred’s more outlandish theories in general, if viruses from space are the source of all evolution on earth, that there was no bigbang and the universe is steady state, etc. so if those are proven right then I will do as Carl on ATHF did and have the wooden end of a broom stick poking out the top of my skull!

See http://www.msnbc.msn.com/id/10908902/

WOAH
The largest is around a millimeter, Brownlee added, and the biggest track is nearly large enough to insert your little finger. In the largest aerogel tracks, investigators can see the black comet dust at the end of the track.

Webcam of the analysis site
http://stardust.jpl.nasa.gov/mission/webcam.html

DOug

"Stardust is a phenomenal success," Brownlee said.

Fantastic - congratulations to everyone involved with Stardust. I am eagerly awaiting my stardust@home "call-up papers". Hopefully I'm not 4F

Doug:

WOAH indeed! That's a thousand times larger than I'd expected - we're not just talking chemistry there, we're into the realms of mineralogy!

Great news!

Bob Shaw

If you get that 1mm slice, your hunt should be easy going.

Great images again on the main Nasa site of the inspection of the sample collector (some might have spotted the team photographing the collector earlier in the webcam). You can see great big splotches of comet particle hits:
Nasa Stardust site

Also announced was a science press conference for tomorrow (Jan 19th) about the samples. It will be on Nasa-tv at 11 am EST (16:00 UTC)

Wow

http://www.nasa.gov/images/content/141267m...e01007_high.jpg

Doug

SPLAT! wow there's enough material there to do GC/MS and NMR on let alone ion microprobe analysis!

Incredible!!! I can't believe that impacts of that size didn't have a MAJOR effect on the spacecraft's trajectory, to say nothing of its structural integrity...score 100 pts. for Ed's "ice cream" analogy!!!


I don't see any legs or wings or anything in the splats...not that comet bugs would need them!

An odd view for someone who calls himself exobioquest.


- Bob

At least they're wearing surgical masks here!

- Bob

The photos are great, I see plenty of splattered bugs (use your imagination), can we get some photos of impacts of dust particle on the aluminum grid? I wonder if by analyzing the damage done to the frame of the collection grid we can guess at how effective the whipple shields were and if we can design lighter weight/smaller whipple shields without sacrificing performance.



Well I beleive pre-biotic panspermia is viable, but thats about as far as I go.

Somehow this just briefly struck me as amusing.

"Allright!!! We got a few grams of dust! DUST!!!!!"




Definitely looks like it was a very good collection mission. Next such mission can go Genesis-style, and have several of these collection things swing out, and bring back a few handfuls of dust or even some genuine chunks.

One thing that , oddly, has totally NOT been discussed is that Stardust has undoubtably collected a third population of samples: interplanetary micrometeoroids.

While the flyswatter (tennis racket, my <deleted>) was extended for interstellar dust collection, the forward facing side intercepted populations of interplanetary dust particles travelling slower around the sun than the spacecraft (many near aphelion), as well as Oort cloud dust particles in retrograde orbits, etc. The rear facing side, beside the interstellar grain population, must have collected populations of particles travelling faster than the spacecraft (many near perihelion). I have heard absolutely no mention of these "background" populations of particles that were collected, I'd assume decidely more abundant than the interstellar particles.

The Comet grains will have hit the collector nearly perpendicular to it's surface in essentially parallel trajectories. The interstellar dust grains, again, will have hit the collector nearly perpendicular to it's surface (by the design of the collection geometry and the known arrival of interstellar material in the solar system), but will have some "dispersion" around parallel impacts to to (I suspect poorly known) random grain velocities.

The background population should hit the flyswatter at all sorts of angles, on the average, not parallel to the target comet's dust and on the average not parallel to the interstellar dust.

It will be very interesting to see what they collected, how much on each side of the flyswatter, and of how many populations of material can be identified.

Indeed, quite impressive !!

Remember - except for the comet encounter, and two specific interstellar collecting periods, the array was tucked up in bed in the capsule

Doug

The interstellar collection periods <two of them> were a few months long, each. The interstellar flux is very low and constant (other than statistics of small numbers fluctuations) and that's for damn small particles, there are few if any bigger ones. I suspect the random interplanetary flux is considerably bigger, it took a long time of studies to even be able to detect the interstellar dust flux above the background.

Did LDEF pick up any interplanetary and interstellar debris during its time in Earth orbit? Just thought it might be useful for comparisons to Stardust's catches.

I think the skepticism in general on this question is because of our lack of knowledge about the interiors of comets.
Let me ask you a hypothetical: suppose it is confirmed that clays and carbonate occur in the interior of comets as Deep Impact suggests they do and suppose it is found they formed from liquid water (the presence of both clay and carbonate strongly implies this is the case).
Given that it has already been long known that organics are abundant in comets, do you think it is likely life exists or existed in comets?



- Bob

Well it all depends on how long those clays and carbonates formed. If it was given many millions of years under liquid water (probably water and ammonia mix) life may have formed, most likely bacterial or nanobacterial (unlikely), if there is a ecosystem on comets then viruses are possible, but could they infect earth life, extremely unlikely: as a virus is very specific to a small set for host organisms, it could only infect native comet life, earth life would not have the proper receptors or biochemistry considering the billions of years of evolution that separates us… unless you don’t believe in that kind of thing.

Like Jon Stewart said a few days ago, its either dust formed billions of years ago, or ~6000 (roughly calculated biblical date) depending on who is wrong. Welcome to the era of "sound" science.

For a detailed Web site on panspermia, see:

http://www.panspermia.org

And directly related to Stardust, this just came from the BBC:

The successful return to Earth of NASA's Stardust capsule offers scientists a first chance to handle cometary dust. The probe bearing it flew close to comet Wild-2 in January 2004.

http://news.bbc.co.uk/1/hi/sci/tech/4627770.stm

One theory for the beginnings of life on Earth is that our planet was seeded by chemicals delivered by a comet. It's a concept known as panspermia.

http://www.bbc.co.uk/science/space/life/be...ngs/comet.shtml

Stardust also managed to collect rare interstellar particles on its seven-year trip. A substance called Aerogel - which is 99.8% empty volume - was used to collect microscopic dust without damaging it. Researchers want the help of people the world over to examine photographs and spot traces of the particles.

http://news.bbc.co.uk/1/hi/sci/tech/4607318.stm

That web site is very bias, I would say http://en.wikipedia.org/wiki/Panspermia
is better.

There is a whole whole range of panspermia theories, some of which are not consider likely or viable by scientific consensuous (like Fred Hoyle's).

Did Stardust bring back water from the comet Wild 2?

http://www.msnbc.msn.com/id/10927236/

Another Stardust press confeence coming up next week, I wonder if they've found something unusual :

NASA ANNOUNCES STARDUST MISSION MEDIA UPDATE

The next Stardust comet mission media briefing is at 1 p.m. EST (noon,
CST), Tuesday, Jan 24 in room 135, Building 2, Johnson Space Center,
2101 NASA Parkway, Houston.

The briefing will be live on NASA TV with questions also from
reporters at participating agency centers. NASA experts will discuss
the analysis of comet and interstellar dust samples returned by the
Stardust spacecraft.

Participants:
-- Dr. Donald Brownlee, Stardust Principal Investigator, University of
Washington, Seattle
-- Dr. Peter Tsou, Deputy Principal Investigator, Jet Propulsion
Laboratory, Pasadena, Calif.
-- Dr. Michael Zolensky, Stardust Curator and Co-investigator, Johnson
Space Center

I don't think so. If there was a big finding, there would be NASA brass there as well.

Hmm. Sure hope so!

I have a silly aerogel question, BTW: How does that stuff stay stable in space? Based on its stated composition, I can't understand why it doesn't outgas like crazy in vacuum & subsequently collapse... Also, is it expected to contaminate the samples in any way?

Aerogel is like a nylon scrubbing pad.. all interconnected web of silica forming a very open sub micrometer spongework. It's not like closed cell foam rubber. It outgassed quickly enough to not blow up, and refills with air sometime on entry fast enough it doesn't get collapsed by pressure.

Okay, that makes sense; I thought that it was "foamy", with trapped air bubbles throughout. Thanks, Ed!

huh, is this not already a common hobby for many people?!

I hope that title is a typo...

LAUNCH ALERT

Brian Webb
Ventura County, California

E-mail: kd6nrp@earthlink.net

Web Site: http://www.spacearchive.info

2006 January 22 (Sunday) 19:28 PST
----------------------------------------------------------------------

STARDUST REENTRY OBSERVATIONS

In response to my request for Stardust reentry observations, I
received the following reports from Gary Baker and Rick Baldridge.

Gary Baker:

"FYI, I viewed the Stardust reentry in cloud-free skies from
Roseville, CA (northeast of Sacramento), no closer than 180 miles from
the reentry ground track. The reentry was on time and its brightness
was impressive given its distance. It was at least as bright as mag -2
(Jupiter), and probably approached -4 (Venus). Its apparent brightness
peaked when the SRC was closest to my location (within 10 seconds of
acquisition), and then held roughly constant as the SRC ventured
further east and lower in my sky. It first appeared pure white, and
then took on a subtle reddish hue that it kept until finally fading
out rapidly at about 2 deg elevation, just above the Sierra Nevada. It
was really moving -- I've seen Shuttle reentries, and the SRC was very
obviously moving faster than the Shuttle returning from LEO. The SRC
appeared very much like a natural meteoric fireball."

Rick Baldridge:

"Yeah, we saw it. William Phelps, Brian Day and I ended up NE of Red
Bluff in the foothills about 880ft elevation on Highway 36 that goes
to Lassen (N40.268, W122.130). I screwed up on the timing by one
minute (too tired and misread the plot I had), so we weren't as
prepared as we would have liked to have been. If Brian hadn't seen
Stardust in the northeast sky and yelled to us, I think all three of
us would have missed it. From our location, it should have first
become visible in Perseus and gone just slightly under Polaris as it
headed toward the east. William and I were looking west of Polaris
when Brian spotted it well to the east of us. We saw it for maybe 25
seconds, and video taped it for much less than that. I sent a
preliminary report to Peter Jenniskens (Ames) via the Stardust
website giving our coordinates, equipment and basic results.

It was moving real fast -- about twice as fast as a Shuttle re-entry
but two to three times slower than a typical meteor. It was definitely
red-orange but showed little or no plasma wake at that point. It did
get fairly bright (about zero-magnitude - Saturn's brightness) and was
increasing in intensity as it descended toward Lassen Peak as viewed
from our location. It all happened so fast that we all said, "What the
__ ? Was that it?" simply because we had driven 5 hours to get out in
the middle of nowhere and it was over in 30 seconds, plus we still had
another 5 hours to drive back to the Bay Area. But we knew that. I'm
glad we saw it. Seeing the fastest re-entry of the man-made object WAS
certainly something, and I'm happy for NASA that it landed
successfully.

The videos I took came out pretty well. Will try to post them soon.
The photos so far are disappointing. One of mine BARELY shows a streak
as the trail heads into the horizon near Mt. Lassen. Haven't seen
Brian's shot yet or William's stuff, but William did get a video and
Brian mentioned last night that one of his photos does barely show the
streak.

Kevin went out on the tarmac at Moffett (NASA/Ames) to get a good
northern horizon but he didn't see anything naked-eye. My brother
Brian was in Fort Bragg but I haven't spoken to him yet to find out
whether he saw it or not.

Some stuff is slowly being posted at:

http://dgilbert3.home.mindspring.com/stardust.htm

http://reentry.arc.nasa.gov/index.html

http://reentry.arc.nasa.gov/firstreactions.html"

Stardust's Return Points NASA Toward More Deep Space Missions
By Michael Mecham
Aviation Week & Space Technology
01/22/2006 09:21:34 PM

The media briefing has now been postponed...

http://www.nasa.gov/home/hqnews/2006/jan/H..._postponed.html

I hope they didn't find the mutilated corpses of teeny tiny little people buried in the aerogel...