LCROSS Science result deferred
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 concerning 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.j... http://apps.nasa.gov/lcross/observations/details/60/ http://apps.nasa.gov/media/lcross/photologue/photos/gheller_200909070612_.jp... - 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
participants (1)
-
Canopus56