Dennis Schlutter University of Minnesota

The following interview occurred on February 3, 2006 between Dennis Schlutter
and Jacinta Behne, McREL Genesis education and public outreach team.

JB: Is sample return/collection something that NASA should continue to invest in?

DS: Yes, it’s a good idea. They can send rovers out, but to do a lot of the science, you need to bring it back to Earth. A lot of it is instrumentation. You cannot put a high resolution mass spectrometer out there to do isotope analysis — you simply can’t.

JB: Can you identify reasons why sample return missions offer benefits that other classes of missions can’t?

DS: Samples that are brought back are here for future study and can be archived for future analysis. There are instruments that aren’t even invented yet that we haven’t conceptualized. When those are invented, the sample analysis gain will be significant. One of the things that comes to my mind is the NANOSIMS — something that just a few years ago wasn’t even conceptualized. Imagine cutting samples from micron size, cut in half, and analyzing them using NANOSIMS instrumentation.

JB: What was it about this mission that said to you, “I need to be a part of this!”?

DS: I came into it in the perspective of working with Bob Pepin, who leads our work here at the university. He was involved and the work pulled me in. He has the original proposal in his office — back when it was Seuss-Urey.

JB: When you observed the hard landing on September 8, 2004, what was your second reaction?

DS: First reaction is, “It’s gone.”

Second reaction is relative to Don Burnett, who said, “The samples are still there.” Do we have problems? Of course. But once we saw the gold foil intact we were relieved. We weren’t that concerned about the dirt because of the amalgamation process. The thing that makes it unique is that the mercury does not attack the dirt. It only goes after the gold. It’s chemistry, and part of that chemical process is that there are not that many things that amalgamate.  Gold is one...and silver and platinum. And if there are others, I’m not aware. This is what makes this process unique.

JB: How would you characterize the mission’s approach to sample retrieval and ultimate dissemination?

DS: Carefully.

JB: How would you characterize the overall condition of the samples?

DS: We have received two gold on sapphire and some gold foil — 4 or 5. The foil was great—but had some brown stain. All samples were heavily scratched and broken for the gold and sapphire.

JB: At what point did you join the team?

DS: I’ve been at this since really early on—1997 I believe.

JB: Were you a part of the initial, pre-flight, collector identification team?

DS: Yes, we started with gold on sapphire and we got simulated implanted samples from Los Alamos National Laboratory. Adding the gold foil came later in the game. We thought there was a contamination problem between sapphire and gold film, which turned out not to be the case.

JB: Tell me, why gold?

DS: You can purify it. It doesn’t react with the nitrogen. It’s a good substrate. There’s a downside to it though: high backscatter. The little buggers don’t stick.  Thirty percent of nitrogen bounces off. It makes the amount of stuff we get to look at 30% less. However, it doesn’t compromise the integrity of the 70% sample we get.

JB: What is SRIM?

DS: SRIM, or stopping and range of ions in matter, shows how a high energy particle slows down and stops when it enters a solid. It has to do with the density of the collection material — the higher the density, the more slowing happens, because of the chance of it hitting things.

The higher the mass, the more it slows down because higher mass elements have more electrons/charges; the effect is that the charges slow down the incoming particle.

The situation right now is that we’re not yet prepared to run a large sample to get good numbers. We’ve run small sample tests. What we get are hints as to whether what we get will be reliable. We want to verify with small samples.

JB: When did you receive your first samples for analysis?

DS: The very first sample we got was a clip of the gold foil. That was mid-March of 2005.

JB: Is “identify, characterize, verify, and extract” your process?

DS: Our role is focused on extraction and analysis.

JB: What was your first breakthrough?

DS: I had amalgamation on the back burner. We tried heating it up, but that didn’t produce the results that we wanted. You have to realize that we’re trying measure tiny, tiny amounts of nitrogen.

JB: If today you were to characterize the chemical picture of your Genesis work for me, what would it look like?

Read more interviews with Genesis team members that tell you about their lives, their jobs, and about the important role they play in the Genesis mission.

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