Philaephilia n. Temporary obsession with logistically important and risky stage of scientific endeavour and cometary rendezvous.

Don’t worry, the condition is entirely transient

Rivalling the 7 minutes of terror as NASA’s Curiosity rover entered the Martian atmosphere, Philae’s descent onto comet 67P/Churyumov-Gerasimenko Wednesday as part of the European Space Agency’s Rosetta mission had the world excited about space again.

Comets don’t have the classic appeal of planets like Mars. The high visibility of Mars missions and moon shots has roots in visions of a Mars covered in seasonal vegetation and full of sexy humans dressed in scraps of leather, and little else. But comets may be much better targets in terms of the scientific benefits. Comets are thought to have added water to early Earth, after the young sun had blasted the substance out to the far reaches of the solar system beyond the realm of the rocky planets. Of course, comets are also of interest for pure novelty: until Philae, humans had never put a machine down on a comet gently. Now the feat has been accomplished three times, albeit a bit awkwardly, with all science instruments surviving two slow bounces and an unplanned landing site. Unfortunate that Philae is limited to only 1.5 hours of sunlight per 12 hour day, but there is some possibility that a last-minute attitude adjustment may have arranged the solar panels a bit more fortuitously.

So if Rosetta’s Philae lander bounced twice, rather than grappling the surface as intended, and landed in a wayward orientation where its solar panels are limited to only 12.5% of nominal sun exposure, how is the mission considered a success?

Most likely, the full significance of the data relayed from Philae via Rosetta will take several months of analysis to uncover. Perhaps some of the experiments will be wholly inconclusive and observational, neither confirming nor denying hypotheses of characteristic structure of comets. For example, it seems unlikely that the MUPUS instrument (i.e. cosmic drill) managed to penetrate a meaningful distance into the comet, and we probably won’t gain much insight concerning the top layers of a comet beyond perhaps a centimetre or so. In contrast, CONSERT may yield unprecedented observations about the interior makeup of a comet.

In science, failures and negative findings are certainly more conclusive, and arguably more preferable, than so-called positive results, despite the selective pressure for the latter in science careers and the lay press. An exception disproves the rule, but a finding in agreement with theory merely “fails to negate” said theory. For example, we now know better than to use nitrocellulose as a vacuum propellant. Lesson learned on that front.

In addition to a something-divided-by-nothing fold increase in knowledge about the specific scenario of attempting a soft landing on a comet, I’d suggest we now know a bit more about the value of autonomy in expeditions where the beck-and-call from mission control to operations obviates real time feedback. Perhaps if Philae had been optimised for adaptability, it would have been able to maintain orientation to the comet surface and give Rosetta and scientists at home a better idea of its (final) resting place after detecting that the touchdown and grapple didn’t go through. Space science is necessarily cautious, but adaptive neural networks and other alternative avenues may prove useful in future missions.

I’ll eagerly await the aftermath, when the experimental and the telemetry data have been further analysed. The kind of space mission where a landing sequence can omit a major step and still have operational success of all scientific instruments on board is the kind of mission that space agencies should focus on. The Rosetta/Philae mission combined key elements of novelty (first soft landing and persistent orbiting of a comet) low cost (comparable to a fewspace shuttle missions), and robustness (grapples didn’t fire, comet bounced and got lost, science still occurred). Perhaps we’ll see continued ventures from international space agencies into novel, science-driven expeditions. Remember, the first scientist on the moon was on the (so far) final manned mission to Luna. Missions in the style of Rosetta may be more effective and valuable on all three of the above points, and are definitely more fundamental in terms of science achieved, than continuous returns to Mars and pushes for manned missions. In a perfect world where space agencies operate in a non-zero sum funding situation along with all the other major challenges faced by human society, we would pursue them all. But realistically, Philae has shown that not only do alternative missions potentially offer more for us to learn in terms ofscience and engineering, but can also enrapture the population in a transcendent endeavour. Don’t stop following the clever madness of humans pursuing their fundamental nature of exploring the universe they live in.


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