Tuesday, October 25, 2011

Meanwhile at Europa, The Plot Thickens

 Divide and Conquer!
A concept for cutting JEO into two pieces brings an Europan Mission back towards the realm of the possible!

VK over at futureplanets reports on two mission proposals to Europa that were delivered to the recent OPAG meeting. The upshot is that by taking a page from the Mars Exploration Program, the outer planets folks have found that they can divide and conquer to explore. By cutting up the science goals and objectives of the US part of EJSM (known as JEO) into two missions - an Europan Orbiter and a Fly-by vehicle - it is possible to reduce the cost of the total missions by over $700 million. More importantly, it divides the program into much more manageable chunks, each of which costs less than $2 billion.

At the same time, it can't be overstated that these are pretty big chunks! It won't fit in under the Discovery Program nor under New Frontiers, so that makes them both flagships. The authors of the report themselves acknowledge that the current funding profile for planetary science as well as the recent Planetary Decadal work against this size of a mission. However, by reducing each mission down below $2 billion, it opens up the possibility that a consortium of countries working together might well be able to bring the cost down to something approaching NF boundaries, particularly if someone else can provide the launch vehicle.

Those of you who read this space frequently will know that even though I am a Martian by training, I was disappointed to see Europa fall off the end of the decadal. It's great to see that ways are being found that could make significant strides in Europa science for less money. At the same time, programmatic balance needs to be addressed, and either of these missions needs to be evaluated side by side with other outer planets priorities of similar cost such as the Uranus or Enceladus Orbiters. Still, it's a hopeful sign.

At the end of the article, vk conjures up the specter of reality. Namely that since both missions are expensive, the possibility exists that the first one to go might be the only one. Therefore it makes sense to consider which is preferred. Vk is unable to make a choice, preferring instead a slightly augmented version of the orbiter. However, given the funding envelope, perhaps we should be considering even more basic versions of these two missions.

What breaks the tie for me is the ice-penetrating radar onboard the fly-by mission. This will tell us if the putative ocean below is accessible at any point and therefore enable a lander when combined with high resolution imagery and composition data from a spectrometer. It would also collect more data and operate for longer, allowing the scientists more of an opportunity to ponder more results (one side effect of short missions is that the funding profile for the data reduction tends to fall of quickly with time). Furthermore, if the ice shell is thin, it will develop the kind of publicity and momentum that will help get the second mission or a lander funded.

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