Thanks for a good outline. I have a fewcomments to add.
Regarding item II-D: “Should therebe a dedicated small-bodies survey mission” I think we should state thatyes, there should be, and sooner rather than later. If asteroids are a futuredestination for humans or for multiple robotic sample return missions, then a goodin-space survey telescope will pay for itself by discovering the easiestasteroids to reach, thereby reducing the cost of those future missions. Investmentin ground-based or space-based surveys is important now because of the longsynodic period for the most accessible asteroids (semimajor axis ~ 1). Such assurvey would also support impact detection goals.
Item III-H mentions ~6700 known NEAs. TheNASA NEO discovery statistics page (http://neo.jpl.nasa.gov/stats/)indicates 7082 NEAs today. The completion level is somewhere around 85%-90% for>1 km, but much lower for smaller NEAs.
I agree with Derek’s comments below.Since all the many objects SBAG covers are “smaller objects” we mayneed to be more specific about which ones he’s referring to. I would saythat for our purposes “small” could mean smaller than the 140 mthreshold defined for Potentially Hazardous Objects. Objects smaller than thisare quite numerous and therefore of interest for various reasons. They tend tobe fast rotators and so as Derek says, they are probably different from any ofthe larger objects that have been visited by spacecraft so far.
Human Spaceflight Advanced Programs
Lockheed Martin Space Systems Company, Denver, Colorado, USA
email@example.com 1 (303) 971-7928
From: Yan Fernandez[mailto:firstname.lastname@example.org]
Sent: Monday, August 02, 2010 6:14PM
Subject: EXTERNAL: Re: [SBAGPopulation Identification & Characterization] sbag roadmap - first d
Hi Derek -- Thanks for the notes, good points.
To everyone else - Any other comments? Deadline is late Tuesday night.
Dr. Yan Fernandez, Asst. Prof. of Astronomy
Department of Physics, University of Central Florida
On 29 Jul, 2010,at 08:46 AM, Derek Sears <email@example.com> wrote:
Smaller objects are also more numerous and more likely to collide withEarth. There are several reasons to expect them to have differentproperties from larger objects, spin rate, porosity, composition, degree ofinternal heating and differentiation.
I agree IR is necessary (don't forget IRTF), and currently we have IR spectrafor <2% of known NEA.
At 09:10 AM 7/28/2010, you wrote:
Hello everyone --Attached please find a rough, first-draft
of the outline for the Population Identification and
Characterization section of the roadmap.
I threw some ideas together that I thought were relevant,
but please feel free to shoot them down and change them.
Or, if you like some of the ideas, you can expand on them too.
The goal here is to have something reasonable by the time of the
SBAG meeting on August 3 and 4. The discussion about this