Published in the December 2014
issue of the Canadian
Nuclear Society Bulletin, Vol.35, No.4.
A Shot in the Dark
by Jeremy Whitlock
Dear European Space Agency,
Congratulations on landing a spacecraft on a comet. Well done. You deserve all the accolades for successfully flying a machine 6.4 billion kilometres to the depths of our solar system, and landing on a four-km wide piece of ice hurtling at 135,000 km/h.
The opportunity for knowledge that you have given the human race is as monumental as it is rare: a once-in-a-lifetime chance, when you consider not just the vagaries of the mission itself, but the fickle winds of policy and bureaucracy that converged on a successful launching of Rosetta over a decade ago.
What, in the name of Arthur C. Clarke, were you thinking when you powered Rosetta and its lander, Philae, with solar cells?
It's not so much the sheer distance from earth, where the sun's energy is four per cent what it is at home - but the almost complete randomness of the landing. What you did was like investing your life's savings in a bank of solar panels to power your retirement home, and then giving the panels one big spin and locking them down in whatever orientation they came to rest.
Are you surprised that poor Philae settled in the shadow of a cliff, and had two glorious days of data acquisition before its batteries died out?
"Yeah but... hey, we still landed on a comet!" - the desperation in this cup of lemonade squeezed from a truckload of lemons was palpable.
Half a century ago we invented something called a Radioisotope Thermoelectric Generator (RTG) - a way to generate power independently of the sun.
It's what powers (and warms) the Cassini probe, orbiting Saturn since 2004 - where sunlight is as rare as common sense in a German energy plan.
It's what keeps the Curiosity rover ploughing over the surface of Mars, even as its solar-powered cousins, Spirit and Opportunity, sputter and stall with each passing dust storm.
A few kilograms of plutonium-238 would have lessened your anxiety over the final orientation of your Philae lander - think of the extra nights' sleep you all would have had without that added uncertainty. With its batteries on continuous charge Philae would have ridden 67P/Churyumov-Gerasimenko all the way to the sun, like a nuclear-powered Slim Pickens from Dr. Strangelove, hooting and hollering its game-changing data all the way.
Instead, you find yourselves gambling on one last-minute nudge before the batteries died, a hope that Philae can be awoken in a year's time, and a prayer that its PV cells won't be damaged by dust and gas of the type that ... well ... spews copiously from a comet as it nears the sun.
Now I know that the EU is not enamoured with nuclear power, but we're not talking about a nuclear fission reactor here - surely the brilliant minds that planned and executed the Rosetta/Philae mission could put politics aside for one moment of unquestionable relevance to the success of a 1.4 billion Euro shot in the dark.
In a way, this outcome is not too surprising - perhaps a cautionary tale about letting idealism and fear guide technical decisions. Especially technical decisions with potentially show-stopping repercussions.
But I can't help imagining poor Philae, all alone in the dark on that dust-covered ice ball, so far from the Euro hand-wringing over nuclear politics - its last thought as it slips into deep sleep (perhaps forever): a wish that the sun-worshippers back home who built its useless power source could see just how small the sun appears in the black, cold distance...
Best of luck with the mission.