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					   GENESIS DISCOVERY MISSION – STATUS AND LESSONS LEARNED. D. S, Burnett, and the Gene-
   sis Project Team. California Institue of Technology (burnett@gps.caltech.edu).


    Introduction:       The Genesis Discovery Mission      recovered, the rest being dust that coats all the remain-
placed a spaccraft at the L1 LaGrangian Point and ex-      ing fragments.
posed high purity materials to the solar wind for 27           Having recovered all possible fragments, the major
months. The collected samples of solar matter were         challenge to the Science and Curation Teams is to deal
returned to Earth for isotopic and elemental analysis in   with the particulate contamination from the crash and
terrestrial laboratories.                                  the necessity to analyze smaller samples than antic-
    Despite experiencing typical delays, the Aug. 2001     ipated.
lauch and subsequent mission were essentially nomin-            At present, the status of the science analysis phase
al. The biggest in-flight issue was the overheating of     of the mission is that, despite serious challenges, we
the Li-SO2 batteries which had a maximum termpera-         are not giving up on any of our original science objec-
ture requirement of 23oC, but by initiating a rigorous     tives, although we have been significantly slowed down
and realistic testing program, in co-operation with        by the various contamination issues.
LMA, we had great confidence in the batteries even             The rest of this abstract is devoted to a summary of
though the final temperature achieved was 60o C. This      science accomplishments to date.
was a case where greater up-front effort to set a more         Beyond saving some material for posterity to ana-
realistic technical requirement would have been highly     lyze (a goal for all sample return missions), the science
cost-effective.                                            objectives of Genesis are: (1) measure the isotopic
    Despite great concern about the navigation risks in    composition of solar matter, with O, N, and noble gas
returning to UTTR, and especially the Project’s ability    analyses having the highest priority; (2) Provide great-
to evaluate of these risks, this part of the misson was    ly improved solar elemental abundances (factor of 3
flawless. As is well known, re-entry however did not       compared to those obtained from solar spectral analys-
go well. An incorrect g-switch installation prevented      es): (3) Measure the compositon of separately-
parachute deployment, causing the crash of the re-entry    collected samples of the three different kinds of solar
capsule (SRC). There were redundant g-switches, but        wind (regimes).
in this case hardware redundancy did not provide func-         Genesis sample analysis proceeds on a broad front
tional redundancy. Because of concern about collector      with 28 participating laboraties around the world. A
breakage if the SRC was parachuted to the ground, we       major advantage of sample return missions is that re-
were set up to do helicaptor mid-air capture. There is     dundant analyses are affordable, in many cases by dif-
no question in the mind of the Project that this would     ferent techniques. Thus not only are data obtained but
have worked very well, but unfortunately we did not get    the accuracy of the data can be independently verified.
a chance to prove it. The cause of the Genesis re-entry    This is critical to a mission like Genesis where every-
failure had nothing to do with using parachutes for        thing we measure is quantitative.
sample mission SRC recovery and this approach should           The figure below shows the fortunate survival of
not be avoided because of the Genesis experience.
    If a spacecraft is doomed to crash, the best planet
upon which to crash is the Earth. In our case, because
of excellent contingency planning by LMA and JSC,
we were promptly able to recover the SRC, which al-
though mangled, was essentially in one piece, and to
recover a large number of broken pieces of collector
materials. Several high priority samples were fortu-
nately recovered intact (see below).
    We expected to have 271 10 cm hexagonal collec-
tors, but instead we now have over 15,000 pieces of
collector materials (greater than about 3 mm in size).
The losses varied greatly among the various collector
materials with many large (multi-cm) samples of sap-
phire recovered, but with only a few small pieces of Ge
of the only sample of “bulk metallic glass” (BMG) This                           result that the solar N isotopic composition is close to
material was used becaused it could be etched uniform-                           that of the Earth and very different from that for the
ly to permit the depth distribution of Ne to be meas-                            atmosphere of Jupiter. General expectations were that
ured. Lunar sample analysis had indicated that the                               atmospheric loss had greatly modified the Earth’s N
isotopic composition of Ne at energies beyond the solar                          isotopic composition, but this appears not to be true;
wind was very different. Surprisingly, the variations in                         moreover there are previously unrecognized major dif-
Ne isotopic composition observed in lunar samples                                ferences in the isotopic compositions of at least one
were exactly reproduced by the BMG analyses at the                               element between the inner and outer solar system.
ETH, Zurich showing that the lunar variations could be                                     For elements, as opposed to isotopes, it was
explained by implant isotopic fractionation, solving a                           expected based on spacecraft data, that elemental frac-
long-standing lunar science problem.                                             tionations would be present between the Sun and the
    The figure below shows very precise Genesis data                             solar wind. However, for elements with low first ioni-
on the isotopic composition of Ar from Washington U,                             zation potentials (FIP<9eV) the spacecraft data are
St. Louis (this work) compared to previous analyses.                             consistent with no fractionations between the Sun and
                                                                                 the solar wind. Genesis data on relative elemental ab-
               6                                                                 undances can test the hypothesis of unfractionated low
                                                     Lunar Reg.                  FIP elements with much higher precision.
                                                                                           A considerable effort has been made to meas-
    Ar/38Ar




                    Apollo foils                                                 ure the solar wind Fe/Mg ratio. The great advantage of
              5.5
                                                                  This work      sample return missions in being able to make replicate
                                 Lunar Reg.
                                                                                 measurements, in this case on different collector mate-
                                                                    air          rials, revealed a problem in that different results were
    36




                                                                                 obtained on two different materials. But another great
                                                                                 advantage of sample return missions, the ability to use
               5
                                                SOHO                             all available technology, solved the problem and we
                                                                                 now have a precise Fe/Mg ratio.
                          1974



                                       1993



                                              2001



                                                           2002



                                                                          2007




                                                                                         1.1
                                                                  Timeline
Lunar sample analyses had shown that the Earth and                                       1.0

the Sun were different, but different sets of data disa-                                 0.9
greed. The Genesis data provide a precise measuremt
                                                                                 Fe/Mg




                                                                                         0.8
of this difference which will tightly constrain models of                                                                        Genesis
                                                                                                                                 Ulysses slow
loss of the Earth’s atmosphere early in its’s history.                                   0.7                                     Photosphere


Similar Earth-Sun differences for Ne based on the                                        0.6

Apollo SWC experiment (U. Bern) are confirmed by
                                                                                         0.5
Genesis.
          The Genesis regime samples address the issue                                   0.4


of possible isotopic differences (“fractionation”) be-
tween the Sun and the solar wind. The different re-                              The above figure shows that the Genesis solar wind
gimes were formed by different solar processes and, if                           Fe/Mg ratio agrees within the photospheric ratio
fractionations were important, these should vary among                           (black) indicating that, within the errors of the photos-
the regimes. Analyses by Wash U and Zurich show                                  pheric ratio, no fractionation of these two low FIP ele-
that small fractionations do exist for He (about 6%) but                         ments has occurred and that at least for low FIP ele-
are not measureable for Ne or Ar. Our highest science                            ments, improved solar wind elemental abundances can
objectives are the isotopic compositions of O and N,                             be obtained. Similar comparisons can be obtained from
and although understanding of the He, Ne, Ar data is                             other elements and for the different regime samples
incomplete, the results suggest that any differences                             which should permit tight constraints on the possibility
between solar wind and solar isotopic compositons for                            of elemetal fractionation between the Sun and the solar
O and N will be small.                                                           wind.
          Very preliminary and relative imprecise data                                     In summary, although progress has been slow,
for the isotopic composition of N are available from                             significant accomplishments have been made since the
CNRS (Nancy, France) which give the very surprising                              Project literally hit bottom on Sept 8, 2004. With a bit
of luck, the major effect of the crash will be a delay in
when science measurement objectives are met.