It’s been a good week for planetary exploration, with NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission and ISRO’s Mars Orbiter Mission (MOM) swinging into orbit around the Red Planet on September 21st and 24th. I have nothing but undiluted delight for both missions, particularly for MOM - India’s first interplanetary mission, wonderfully executed so far. The three other spacecraft in Mars orbit - MRO, Mars Express and Mars Odyssey - are largely interested in the surface of the planet, but MAVEN and MOM will be training their instruments primarily on the thin Martian atmosphere. Some of the Big Questions about Mars are how what was once a warmer, wetter planet became the frozen desert that it is today, and whether it was or remains at all habitable. MOM and MAVEN have different but complementary instruments designed to supply partial answers to those questions. May the Sun shine warm on their solar panels, and may the ground beneath them and the air around them be ever interesting.
I write this because much of the coverage of the two missions has been rather fixated on the fact that one cost considerably less than the other, and I think that this is something of a red herring. That is to say, it is beside the point. If we’re talking costs, the major point to be made is that both missions were accomplished at a miniscule cost. Currently, NASA’s budget hovers at around 0.1 % of the GDP of the United States, and ISRO’s budget is 0.038 % of India’s GDP (the numbers are almost as small when considered as fractions of the national budgets of both countries). Keep in mind that these are the whole budgets of the two agencies - covering not just solar system exploration, but everything they do in terms of keeping watch over our own planet. Let’s be clear about this; at this time, there is very, very little to be gained by snipping away at planetary science budgets or abandoning exploration - and there is the universe to be lost.
To me, the most compelling justification for studying the planets is simply that we live on one. In that light, planetary exploration is a profoundly practical proposition. Every mission allows us to test our grasp of basic physical principles in unfamiliar surroundings. When an observation agrees with our predictions, it strengthens our understanding of the processes that shape all planetary bodies, including our own. Every time we see something that we haven’t seen before or do not understand, we widen the boundaries of what we know a little further. The Solar System, with its strange and varied worlds, resembles a grand experiment awaiting observers. It seems a shame not to observe it.
It has been said that in setting out to discover other planets, it is ultimately our own that we end up discovering, in more ways than one. I think Carl Sagan put it best:
Barely 60 years have passed since the first spacecraft ventured purposefully beyond Earth orbit. Imagine that. Only in the last 60 of the 4,600,000,000 years that our planet has witnessed, have we begun to seriously answer questions that generations before us must have asked of the night sky. Were we to turn our backs on those questions, our lives and imaginations would be infinitely poorer for it.