Extraction technology: We successfully tested the keystone extraction system in October, using a stainless steel arm. It was clear, however, that a vibration isolation table is required in the Cosmic Dust Lab. The table was ordered in October, and just arrived at JSC on Dec. 5.
Mike Zolensky, Ron Bastien and Jack Warren are now switching CDL over from IDP work to Stardust interstellar work. This will be complete before 1 Jan.
We have completed and tested the laser safety stop. This consists of two pieces of retroreflective tape on the micromanipulator head and two laser heads. If either laser beam walks off of either tape, the micromanipulator is powered off. This is in place as a safety net in the event of a software or hardware malfunction in the micromanipulator that might cause it to more incorrectly and damage the collector.
One of the recommendations of the Stardust Oversight Committee of CAPTEM during the discussions of the ISPE was to be sure to preserve the aerogel around the tracks, in case any volatile material from the projectile diffused into the aerogel and was trapped. Dave Frank has developed a neat technique for doing this without adding significantly to the time required for keystoning. The sections of aerogel flanking the “pico” part of the picokeystone are mostly cut but ~10 microns is left as an attachment, so that they are not lost but can be plucked off using microtweezers after extraction. A picture is worth a thousand words here — we will include this in the next blog.
We have developed a technique that will greatly improve the speed of scanning when this resumes, but eliminating the time-consuming step of making a manual focus map before each scan. This will enable UCB to initiate and control scans remotely, thus reducing the burden on Jack and Ron at JSC.
Plan
Extraction:
UCB will provide a map of IS candidates and off-normal tracks to be extracted over the next few months.
JSC will scan these tiles at low magnification in the Stardust Lab using the same photodocumentation techniques used for the cometary tiles.
JSC will also scan the foils around these tiles.
In parallel, UCB will install the laser safety system on the extraction system in Cosmic Dust.
UCB + JSC will do practice keystoning on the flight spare, and will extract at least five successful blank keystones and picokeystones.
The flight tray will be returned to CDL from the Stardust lab. We will then extract several blanks (at least three) from the flight tray to ensure that keystoning is not a problem on the flight aerogel (that was in space for seven years).
We will then extract five high-angle tracks as regular keystones. These will be mounted on micropickleforks and imaged. Based on these images, we will decide on the next steps.
We will then extract ~10 of the interstellar candidates in picokeystones. We will choose candidates to maximize the diversity in their appearance in the imagery that we have now. We will learn a great deal just by looking at them from the side. These will be mounted in clamshell TEM grids, then put on “APS” mounts. We are working on acquiring from Ladd Research custom clamshell TEM grids made of Al, Mo or Nb.
As we extract keystones, we will post images of them to the blog.
As there is time in the schedule between extractions, we will resume scanning of the tray.
We tentatively plan to do the following first steps on the extracted keystones, after imaging.
FTIR analysis of these keystones on beamline 1.4.3 at the ALS. This is a long-shot since these are not likely to contain significant organics, but it is very low risk, since FTIR is the only technique beside optical microscopy that is completely non-destructive. (There is always a handling risk, of course.)
We will send one of the tracks to each group, more or less in the order in which they have synchrotron time, to do XRF/XANES/XRD analysis on them. The goal here is to see what major elements (except H, C, N, O and Si) are present, and if there is crystalline material. The baseline plan for the interstellar plan should be similar to that for the high-angle tracks.
Andrew Westphal