Thursday, February 19, 2009

Various Thoughts on the Flagship Mission

One of the readers of this blog sent me a note asking why it will take almost 11 years to launch the just selected Jupiter Europa Orbiter (JEO) mission. I have not followed all the ins and outs of this, but I'll share what I think I understand. Normally, a new mission takes approximately four years to develop after it receives a new mission start. Prior to that, it is common to spend some time in pre-start mission development. If money was no issue, it would be reasonable to expect that JEO would launch in the mid 2010s. A 2007 study of a Europa Explorer (the predecessor concept to JEO) presumed the launch would be in 2015. If you look at NASA's expectation for launching the Flagship mission a year ago, the target date was 2016-2017.

After that time, NASA slipped the launch date to around 2020. The stated reason was to align NASA's schedule with ESA's schedule, which could not fit a launch before that into its funding profile. I suspect that the looming cost overruns of the Mars Science Laboratory might have made the delay on NASA's side inevitable. In any case, now that the MSL cost overrun is on the books, funding for preliminary studies of JEO are slim for the next couple of years. So, we have a 5 year push out in expected launch date over the last two years.

Could NASA pull in the JEO schedule if ESA does not select its potential contribution, the Jupiter Ganymede Orbiter (JGO) in 2011 to fly? Potentially. However, I suspect that it will take awhile for NASA to work through the problems created by the MSL slip and the earliest launch probably would be in the 2018 timeframe at best. Without access to NASA's funding expectations, this is speculation, however.

On another topic, what if ESA doesn't select JGO? How might the JEO mission change? The major loss from JGO would be the intense set of flybys of Callisto and the study of Ganymede from orbit about that moon. JEO has an excellent set of instruments for studying the moons of Jupiter during flybys. In fact, a series of flybys are planned of all four Galilean moons. JEO cannot carry enough fuel to orbit Ganymede as well as Europa, so the study of Ganymede from an orbiter would be lost. On the other hand, JEO could delay its orbit insertion at Europa to allow more time for more flybys of other moons. (More flybys than the planned handful at Io are probably out because of radiation issues.) JGO would spend approximately a year conducting 19 flybys of Callisto. JEO could spend an additional year carrying out flybys of either Callisto, Ganymede, or both. If such a plan was implemented, I would expect Ganymede to receive the lion's share of additional study. The scientific community has prioritized further study of Ganymede over Callisto.

Jason Perry has posted another excellent analysis on his website about what the selection of JEO with its planned Io flybys would mean for the proposed Io Volcano Observer (IVO). He correctly points out that IVO would conduct more flybys (at least 7, probably 14, and possibly even more) compared to JEO's 4. The flyby geometry selected for IVO would also be more optimised than JEO would be have. (JEO will use the Io flybys in part ot set up later encounters with other moons and hence is constrained in the selection of flyby geometries.) Jason points out that the proposed IVO instrumentation would be more optimized for Io studies than the proposed JEO instrumentation would be for Io. However, this may not remain the case. The proposed instrumentation for JEO is a strawman to show capabilities and allow conceptual design of the orbiter. The actual instruments will be selected from proposals submitted by scientists in several years time. It is very possible that the winning instruments will be tuned to do better at Io than the current strawman payload would.

Two missions to the Jovian system are on the official list for the next New Frontiers mission ($650M). One is an Io observer and the other a Ganymede observer. The selection of JEO and possibly JGO would seem to make the selection of the Ganymede observer unlikely in my opinion. JGO is the Ganymede observer done right.  The Io observer faces hurdles in terms of being selected, too. As Jason points out, there are still valid reasons to fly IVO. The science it would return over what JEO will and may return has to be better (and at lower risk) than the science from all other proposed missions. That may not be possible. I would love to see IVO fly, but I have strong doubts that it will. (Note: IVO is a Discovery mission ($450M) and not a New Frontiers mission. However, I think this reasoning still applies.)

As my final thoughts, I'll speculate on what may be a crowded place the Jovian system could be in the 2020s. This year (2009) is the year of the moon with Chinese, Japanese, Indian missions there now. ESA just finished a lunar mission and NASA will launch its soon (with more to come). The 2020s could be the decade of Jupiter. NASA and ESA may have orbiters exploring the moons and observing Jupiter itself. The Japanese space agency, JAXA, is considering an orbiter to explore the Jovian magnetosphere. Russia is considering a lander for Europa. Other nations likely will have the capability to send missions to Jupiter. What might those craft do? Additional craft to explore the magnetosphere would be useful. A craft in polar orbit around Jupiter could study the polar regions of Jupiter, keep an eye on Io, and explore another corner of the magnetosphere.

Unless new news comes out about JEO, I'll take a break from this topic for a bit.  In the next few weeks, the NASA FY10 budget will be released and will show the new administration's priorities for planetary exploration.  There will be meetings of NASA's scientific advisory boards for Venus where a Flagship mission will be proposed, the Outer Planets where we may learn more about the issues that led the selection of Europa Jupiter over Titan Saturn, and Mars where replanning the exploration roadmap for the next decade will begin.  I also want to complete the discussion of concepts for missions for the next New Frontiers mission selection.


  1. That would be extraordinarily challenging for the Russians. They haven't done any space probes since ... Mars 96? If they pull off Phobos-Grunt, maybe they can pull off a Europa lander. I'd have my doubts though. Did the Soviet Union ever venture into the outer system?

  2. Nope. Never beyond Mars (and never a completely successful mission there in 14 tries).

    G Clark

  3. I keep wondering whether building two identical Flagship-class vehicles might only cost as much as a Flagship plus a New Frontiers mission, but I've never seen a breakdown of what these things cost.

    I remember how at one point NASA routinely sent spacecraft in pairs, but lately, except for the two Mars Rovers, they don't seem to think that way anymore. What I'd like to see is a breakdown of how much of a mission is non-recurring engineering (which would be shared between two probes), how much is the probe itself, how much is launch vehicle (which might come down sharply with things like SpaceX Falcon 9), and how much is operations (there might be some economy of scale monitoring two identical craft).

    Perhaps these days we wouldn't expect to get 2x the data from identical spacecraft at the same target, but then perhaps they don't need to go to the same place.

    For example, suppose NASA wanted to build a Neptune orbiter. What would the cost effect be of making two and using the other as a Uranus orbiter? They'd arrive at different times, so one could imagine using the same support crew for both. Would that really essentially double the cost of the first mission, or would it only increase marginally?

    I'd imagine NASA has done this sort of calculation, but, if so, I've never seen mention of it.


  4. Greg -

    I've read that an exact duplicate of a spacecraft and it's instruments can be purchased for 50-60% of the cost of the first. I don't know if that includes the launch vehicle.

    A Titan mission would have a new set of instruments, which would be expensive for a flagship mission ($100M? $150M?). Perhaps a second craft to fly to Titan for $1.5B to $2B?

    Originally, Cassini was part of a dual spacecraft build with the second craft to rendezvous with a comet. Congress effectively forced NASA to kill the comet mission. I understand that Cassini survived only because of the international nature of the mission.

  5. Yes, I remember when it was "Cassini-CRAF".

    Still, perhaps I'm letting myself be seduced by the superficial similarity between Uranus and Neptune, but it does seem that if there are any economies of scale, NASA ought to think in terms of sending the same type of vehicle to both worlds.

    I realize I'm fantasizing about a mission that wouldn't launch before I'm 80 . . .