Discovery 2012 Options

[dvandorn]

I also have to say I'm happy with the choice of InSight, as I've been seriously wanting heat flow data from Mars for a really long time, and a good, sensitive seismometer is worth an awful lot, too. (Too bad the seismometers attached to the Viking lander structures didn't work very well, if at all.)

Yet, as so many have expressed, it's bittersweet. We would all, I'm sure, love to see the vistas from a Titanian lake. However, remember that vistas are only one part of the reason for exploring our solar system. A good TiME mission would likely have given views of the ripples on the surface of the lake that are like a meter away, unless it would have had some kind of mast to raise a camera well above the top of the waves. A detailed study of the liquids in the lake would have been the primary mission, not sending back stirring images of distant shores. And as important and interesting as is that science, if we had to make a choice, I guess I'd prefer getting the heat flow and seismic data from Mars first.

Besides, a TiME-like probe could eventually be incorporated into an as-yet-undefined flagship mission to the outer planets. There likely won't be any further flagship-level missions to Mars in the near term, at least until we're ready to consider sample return. I like the idea of using a Discovery slot or two to fill in the gaps in our Mars dataset, to help us decide on the parameters of a potential MSR mission.

It will take a great deal of time to pony up the resources to explore all the places we want to explore. I guess in this case, we should rejoice in what we can get and cultivate patience for what we didn't get this time around. Because, as with orbital trajectories, what goes around, comes around.

-the other Doug

[vjkane]

I also have to say I'm happy with the choice of InSigh

This is how I put it in my post announcing the decision:

"NASA's renewed focus on Mars missions provides a compelling reason for the InSight mission. Missions over the last twenty years have greatly deepened our understanding of Mars, and several missions continue their explorations. The Curiosity rover's mission is just beginning. Starting in 2018, NASA plans to begin a new series of missions. InSight neatly plugs a gap in our exploration of Mars -- the deep interior. In many ways, the surface geology and atmospheric chemistry of any planet are consequences of the composition, structure, and activity of the deep interior. With InSight, we can begin to link the interior, surface, and atmosphere in new ways."

My only concern is that NASA's planetary program not become only a Mars program. The next New Frontiers selection will help; the mission will be selected from:

- Comet Surface Sample Return
- Lunar South Pole-Aitken Basin Sample Return
- Saturn Probe
- Trojan Tour and Rendezvous
- Venus In Situ Explorer

[rlorenz]

(Too bad the seismometers attached to the Viking lander structures didn't work very well, if at all.)

Viking 1's seismometer didnt uncage, so no data
Viking 2 data was dominated most of the time by wind noise on the lander (which Insight's deployed seismometer with wind shield
will largely eliminate) although there was a pretty low background at night when winds were low. There was one possible M3.5 event
detected, but there was no contemporaneous wind data to eliminate a gust or so as the cause of the signal.

As it happens, I have NASA funding to examine the Viking seismology record for evidence of dust devils (the seismometer was
sampled more frequently than was the meteorology package) and, with the cooperation of one of the original
investigators, to archive the data (acquired long before PDS existed, and in a rather awkward format on NSSDC) in a more
friendly format.

I guess I'd prefer getting the heat flow and seismic data from Mars first.
.........
I guess in this case, we should rejoice in what we can get and cultivate patience for what we didn't get this time around.
Because, as with orbital trajectories, what goes around, comes around.

You can do Mars geophysics now (2016), or in 2018, or in 2020......( or you could have done it in 1976, or ....) but we only discovered Titan's north polar seas in 2007, when TiME was first exposed to NASA, and good Earth view from Ligeia won't happen again until 2040. I am likely about the youngest person involved in Huygens from its beginning and I and colleagues were able to bring Huygens experience to bear on TiME.
I will be 71 years old in 2040.

NASA has its reasons for making its selection. Insight will be a good mission. But with respect, I do not agree with your programmatic reasoning.

[vjkane]

But with respect, I do not agree with your programmatic reasoning.

I thought the alignment of the planets made the compelling case for TiME. Scientifically, there were three winners among the finalists, but only one mission that couldn't be done until 2040 without considerable expense.

At least three outer planet proposals were made for Discovery -- TiME, Io Observer, and Journey to Enceladus and Titan. None were selected. Since we aren't privy to the debrief data, we can't know if they were simply too ambitious for Discovery budgets (although the PIs were experienced and should have been realistic). Alternatively, all three might have been judged to fit within the Discovery budget and the decision was to go with the lowest technical risk mission: InSight.

In the past, Discovery mission opportunities were frequent enough that teams could stay together and refine their proposals for the next competition. With five years between selections, that may prove difficult.

InSight will be an awesome mission (as Chopper would have been), but I will always regret that we didn't take advantage of the TiME opportunity.

[Explorer1]

Ontario Lacus is in the southern hemisphere. It could easily become an alternate splashdown site, right?

[rlorenz]

Ontario Lacus is in the southern hemisphere. It could easily become an alternate splashdown site, right?

No. small and shallow

[ElkGroveDan]

I will be 71 years old in 2040.

Yes, but by then 71 will be the new 51.

[stevesliva]

My real question for the future is whether this discovery selection going to Mars means the Mars budget will shrink more.

[mcaplinger]

My real question for the future is whether this discovery selection going to Mars means the Mars budget will shrink more.

Ostensibly, no. For some past Discovery AOs Mars has been explicitly excluded from consideration (when there was a Mars Scout program you proposed Discovery-class missions to that) but that wasn't the case with this AO, and my understanding is that Discovery, regardless of target, is independent of the Mars program. Of course how this really plays out, no one can say. Certainly the part of the planetary science community interested in targets other than Mars has little reason to be happy about this selection.

[Phil Stooke]

And yet it's only this month that we get the suggestion that 'ice' of some type may float on the surfaces of these lakes. Truth is we are still a long way from digesting what Cassini has to tell us - the mission is still active with more radar and VIMS mapping and much more analysis still to come. Titan science is not yet mature enough to support a mission like this. I know many ardent supporters of Titan will disagree - it sure is an enticing target - but it's premature to plan a new mission (see first sentence).

Phil

[Juramike]

That's kind of a circular argument: if we knew everything about a place, we wouldn't need send a probe there, would we?

A lot of the theoretical possibilities (floating methane ice, for example) would be constrained by having one nice in situ measurement of the composition and liquid temperature of a Titan lake. The bummer is that the sun will set too soon over Ligea Mare, so we'll have another 13+ years to ruminate over the Cassini data before could we send a mission to the northern lakes....

[And I'm an ardent Titan supporter.]

[vjkane]

The bummer is that ... we'll have another 13+ years to ruminate over the Cassini data before could we send a mission to the northern lakes....

We can do a lake mission at any time. Since we missed this Discovery mission opportunity, a mission would have to use a data relay craft, which could either be the carrier or an orbiter. Just more expensive. The Decadal Survey costed such missions out to ~$1B if I remember correctly. See here and here.

Unfortunately, the Survey members concluded, "The exploration of Titan's hydrocarbon lakes has high scientific potential and the Titan lake lander concepts appear feasible. However, based on the costs and the relatively limited science scope of a stand-alone lake probe without the orbiter and balloon elements, the stand-alone lake probe concepts were judged to be lower priority than a lake probe which was an element of a flagship mission, or some of the other mission concepts studied."