LCROSS Science result deferred

0 views
Skip to first unread message

cano...@yahoo.com

unread,
Oct 10, 2009, 12:34:48 AM10/10/09
to LCROSS_Observation

The LCROSS impact was a bust from the amateur imaging perspective.
The plume did not follow the pre-impact prediction model and was not
visible. Amateurs and large professional telescopes (Palomar) did not
report any contemporaneous visible plume. At the LCROSS press
conference, a Spex guidescope image from the NASA Infra-red Telescope
Facility was displayed as part of the press conference materials. It
contained a time index about 40 seconds after impact (11:32UT) and was
labeled "no plume detected yet."

While the results for amatuers and the general public were non-
existant, with respect to the important science objectives of the
mission at the LCROSS post-impact press conference -

http://www.youtube.com/profile?v=MEV4IoUh_Gk&user=NASAtelevision

- key LCROSS team members stated that even with the reduced plume,
basic LCROSS science goals can be achieved with what limited data was
collected. Although the LCROSS Team has done some preliminary
analysis of spacecraft spectroscopy, they are holding up on releasing
any results for about a week in order to do a full analysis.

Positive first look data collection results reported at the post-image
press conference:

1) Colaprete indicated he felt that they collected shepherding
satellite spectroscopy sufficient to give an answer to the basic water
question.

2) A chart shown during the conference illustrated that the MMT
Observatory ( http://www.mmto.org/ and archived streamed video
http://www.mmto.org/lcross/ ) captured a good before and after
spectrogram.

The post impact press conference was a little comical with the
scripted portion of the presentation straining credibility by overly
pressing a positive spin message against a backdrop of a negative
plume result. (This in part has to be attributed to the fact that
most of the team members had been awake for about 24 hours and were
doing the public and newsmedia a favor by solidering one last press
conference just after impact.) The main presentation didnot squarely
address the failure of the plume model. The failed plume model issue
was left for follow-up press questions.

The negative plume result hopefully will spur improvements in future
models. There are many potential causes of the negative plume result
that have well-discussed, including:

1) The model used for low-density spheres is wrong (a point that Jim
Mosher has argued for sometime in the LCROSS observation group).

2) Modeling using low-density spheres does not capture the behavior of
a "belly flopping" "hollow-tube" impactor.

3) The booster hit angled terrain, so the plume angled to one side.
(One of the early release slides from a near-infra red camera showed
the impact flash may have been non-circular. But principal
investigator Colaprete noted that the "t-shaped" set of pixels that
define the impact flash may be an imaging artifact.)

The lesson learned from public outreach for the LCROSS event and the
Deep Impact event is that public communications concernign impact
predictions should be distributed in the form of Bayesian probability
statements. NASA public communications policy of issuing blanket
"you'll be able to see it" statements along with taking a "we are
NASA, we know what we are doing" stance, and then rallying the public
to attend observing events, impeaches the credibility of the agency in
the public's mind where it meets the potential for experiment
failure. Issuing probability estimates for the observability of such
public events would communicate to the public the uncertain nature of
conducting experiments. A public outreach practice of "point your
telescopes and take our word for it" is not in the agency's self-
interest.

Amateur imaging before the event brought out some amazing imaging
examples. Probably the one of the best in the "personal spaceship
portal" category was by an amateur under the handle "Heller
Observatory" who uploaded to the LCROSS Citizen Science site:

http://apps.nasa.gov/lcross/observations/details/61/
http://apps.nasa.gov/media/lcross/photologue/photos/gheller_20091007060158.jpg
http://apps.nasa.gov/lcross/observations/details/60/
http://apps.nasa.gov/media/lcross/photologue/photos/gheller_200909070612_.jpg

- and in _Selenology Today_ no. 15.

http://digilander.libero.it/glrgroup/selenologytoday15.pdf

In Utah, a small group of about 6 personal telescopes watched along
with the club's 8" Clark 1919 refractor, a 1960s vintage 16" Ealing,
and the club's 32" constructed Cassegrain. The 20 or so attending
club members, being experienced amateurs, were understanding of the
negative imaging result and in general had a good time.

For my own part, I enjoyed and learned alot from following LCROSS for
the last year. The question of lunar polar water-ice remains an
important one that ultimately will require ground truthing of positive
remote sensing results. I hope to be reading about a positive water-
ice science result for the LCROSS mission sometime in the next couple
of weeks. If the science result is positive, hopefully the next lunar
polar mission will be a lunar rover with deep drill capability, e.g.
something along the lines of the concept Mars deep-drill lander. I
hope the LCROSS team members' careers progress to be part of such a
future mission.

I acquired an ImageSource camera just a day before the impact and took
it for a test run on impact day - with marginal results due to
inexperience. Those poor images are linked here in the hopes of
encouraging others amateurs to get started in lunar imaging. Gotta
start somewhere -

http://www.youtube.com/watch?v=yce2dxdUt80
http://www.slas.us/gallery2/main.php?g2_itemId=2439

See ya the next time NASA does something cool. Here's hoping for a
wet report in a couple of weeks.

Clear Skies - Kurt

Patrick Wiggins

unread,
Oct 10, 2009, 1:00:57 AM10/10/09
to lcross_ob...@googlegroups.com
Thanks for a great report Kurt.

One minor correction: The club's refractor is a 200mm Brandt mounted
on a 1915 Clark pier. I only wish the scope _was_ a Clark. :)

But regarding this morning's new conference, I agree that NASA
probably could have handled it and the releases leading up to it a bit
better.

But I was even less happy with the "I want it now!" attitude of some
members of the media.

I mean, the LCROSS team members had only had an hour or so to prepare
visuals and, for the most part, had not even had a chance to look over
the data. And other data, like those from LRO had not even been
received yet.

There's just no such thing as instant science.

patrick

Reply all
Reply to author
Forward
0 new messages