Fieldwork in the Atacama Desert, Chile

Friday, 21 June 2019

The Nemesis Project


I’ve repeatedly heard that every academic, at some stage in their career, has that one project that just won’t behave itself and become a nice little publishable package. Experimental results lead to more questions than answers. Reviewers say the ides are interesting but are unconvinced by the conclusions or have issues in the reliability of the method. You're rejected but encouraged to re-submit. The whole thing drags on for years, quietly ticking away in the background, while research avenues with more promise for short-term gain are chased instead. But the nemesis project never dies, it stays there at the back of your head. Too much time and effort has already been invested, you’re in too deep to give up on it now.

My own mini-version of this has just ended. My nemesis project has just been published in Astrobiology (link, and link to non-paywalled pre-print) 3 years after my supervisor scribbled down a ‘cool idea which won’t take much time to test’ (I may be paraphrasing there, it was a long time ago). This is not my usual post-publication summary of my work, I will hopefully write that soon, instead this is a story of how much behind the scenes failure can have gone into one, small, relatively insignificant, successfully published paper.

The idea for the project came out of the PlanetaryProtection of the Outer Solar System project, which I have written about before (link). In one of the early meetings back in 2016 my supervisor, clearly paying full attention to whatever was being discussed at the time, scribbled a vague experimental idea onto a scrap of paper. This idea was to see if we could use a well-established environmental sampling technique (solid phase micro extraction, SPME) to test spacecraft hardware surfaces for organic contamination.  Now this was interesting as organic contamination is a big issue in planetary protection, we don’t want to send dirty spacecraft with highly sensitive instruments to the (currently) pristine icy moons of the outer solar system. We’d end up only detecting muck from Earth and so either getting all excited over nothing, misinterpreting it for evidence of alien life, or, a real interesting extra-terrestrial signal would be missed, lost in background noise from the contaminants. Current methods employed for detecting contaminants on surfaces tend to be time consuming, complicated and may involve multiple solvents being used in the process – themselves potential contaminants.

The premise was therefore simple: Get some stainless steel to use as a budget stand in for a spacecraft surface, contaminate it, see if SPME (coupled with GC-MS) is sensitive enough to detect contaminants at the levels of cleanliness required for life-detection missions.

The first version of this study just involved leaving some stainless steel L-shaped brackets (bought from a hardware store) out in the lab to collect fallout contamination from the air and also handling them with and without gloves to see if they picked up anything detectable from hand transfer.
To be scientifically valid a study like this must be reproducible, so many repetitions of everything being tested are needed, simple, but monotonous, time consuming work – perfect for an undergraduate summer internship! Georgios, a 2nd year undergraduate and now co-author on the final paper, gave up 6 weeks of his summer in 2017 to do this, creating loads of data for me to work up afterwards. Now initially we thought this first version of the study was pretty good, however the reviewers had other thoughts.

Reject but encourage re-submission.

The issues basically boiled down to our method being a bit woolly and bullsh#t (again, paraphrasing). How could we know what was on the surface to detect and therefore how sensitive the method was if we hadn’t specifically contaminated it ourselves at a known concentration? We’d basically skipped the proof of concept stage and gone straight to real-word testing (well as real as you can get without a real spacecraft)...So yeah, fair enough.

Not having scope to dedicate 6 weeks of lab time to completely redo the experimental side of this study myself, the project had to get shelved until the following summer (2018) when I could get a second student, Yuting, who was keen to get some experience in the mind-numbing, soul destroying boredom of repetitive lab work.

In the meantime, I took the reviewer comments, which despite being rather critical were all very valid and helpful, and developed a whole new method for testing the sensitivity of this technique. This was to be much more scientific, creating a whole range of solutions of astrobiologically-relevant contaminants to contaminate a surface with much better-defined properties (although it was still basically just a steel nut).  

Once again, the student project seemed a success. Yuting produced a shed load of nice replicate data over the summer, which I turned into a completely new manuscript. None of the data set from Georgios’s original experimental run even made it into the new work, and after a few weeks of tidying up and writing we re-submitted.

Again, however, the reviewers didn’t quite agree, while they did think the method was now (mostly) sound, they didn’t agree the results were as promising as we did and wanted more and better data. Almost annoyingly this wasn’t a rejection this time, there was now a time pressure involved with a re-submission deadline. I could have ignored it and waited another year, but there was an end in sight, a way to kill this thing. Jon just needed to work some magic to tweak the mass spec settings to decrease the noise and make the data more convincing. Unfortunately, this meant I now had to repeat all the experimental work with the new settings myself, replicating a whole summer student project in about 3 weeks.

This was not fun, but it worked.

Now at the end of it all, it is clear that without the multiple knock backs and the intermediary time periods to just think about how to improve the methodology, this study would’ve been pretty rubbish. This is definitely a case where the review process has greatly improved an original idea and has shown me that rejections don’t always have to be a bad thing, they can be an opportunity. However, this only took 3 years to take down, I’m not sure how I’d feel if this had grown into some 5 or 10 year, or even career-spanning, monster.

Maybe that’ll be the next quick project…