"thor" Mars Mission To Seek Underground Water Options

[lyford]

the thunder god went for a ride
upon his favorite filly
"i'm thor!" he cried
and the horse replied
"you forgot your thaddle, thilly!"

hadn't remembered that since I was a kid

Thor-Able at astronautix.com

[Guest_AlexBlackwell_*]

It's certainly an interesting Mars Scout idea, and one I would never have dreamed of...

Folks, you heard it here first. And I'll go ahead and bookmark this message. If this mission concept is ever selected, I'll need ammunition to refute any claims that Christensen "stole" the idea from you, or that you were a driving force behind the mission.

[nprev]

...I actually was thinking of an old Mother Goose & Grimm strip captioned "Suddenly, Thorro realized that he should change his name" as he struggled to carve "TH"...

In all theriousness, though, Thor is an exciting concept. BTW, will Phoenix or MSL carry a seismometer? I'm guessing that an impact of this magnitude might be enough to yield at least a little core/mantle structural data, especially since it will be so predictable...

[Guest_BruceMoomaw_*]

No seismometer on Phoenix or MSL; but there currently IS a plan to include one as part of a detechable package of geophysical instruments that will be left behind at the landing site by the ESA's ExoMars rover in 2011 -- the first of a hoped-for series of replacements for the Netlanders. if the ESA actually funds ExoMars and it lands successfully before the Mars Scout (which are very big "ifs"), it might be able to pick up the thud.

[Guest_BruceMoomaw_*]

Folks, you heard it here first.  And I'll go ahead and bookmark this message.  If this mission concept is ever selected, I'll need ammunition to refute any claims that Christensen "stole" the idea from you, or that you were a driving force behind the mission. 

Laugh while you can, monkey boy. Yesterday I had a protracted phone conversation with Paul Lucey at U-Hawaii, as a result of which I may start pushing the Europa penetrator idea again. More on this later.

[ljk4-1]

No seismometer on Phoenix or MSL; but there currently IS a plan to include one as part of a detechable package of geophysical instruments that will be left behind at the landing site by the ESA's ExoMars rover in 2011 -- the first of a hoped-for series of replacements for the Netlanders.  if the ESA actually funds ExoMars and it lands successfully before the Mars Scout (which are very big "ifs"), it might be able to pick up the thud.

I know the Viking landers' seismometers did not detect very many marsquakes (and in fact the Viking 1 instrument never got its pin out). Is this why they never put one on any Mars lander after that, if I am correct here? Will they change that policy in the future?

I hope some day we can have a long endurance seismometer on Venus. And imagine one on Io: It would probably wear out in a month.

[Guest_BruceMoomaw_*]

The inability of the Viking 2 seismometer to detect any provable quake at all over 2 1/2 years was indeed the reason why the US put the kibosh on seismometers since then. It made it clear that Mars' seismicity level was low enough that you need a highly sensitive seismometer directly coupled to the ground, with a low profile to avoid wind noises -- that is, a lander or package specifically designed for the purpose. Also, you must lay at least two or three down simultaneously to locate any epicenters -- and, except for the 2003 rovers (which were obviously unsuitable), all Mars landers since the Vikings have been singletons except for the disastrous Russian attempt to set up network science (including five seismometers) with Mars 96. (The original design for Mars Pathfinder DID call for the rover to deposit a tiny seismometer on the surface -- linked to the lander by a cable -- as well as for a neutron spectrometer on the rover; but those two instruments very quickly got the boot due to weight problems.)

The new US Mars plan calls for a Mars science network mission in 2020; but there was some interest at MEPAG in trying to advance it to 2016 (an idea I aftually oppose for reasons I won't go into here). And of course it's possible that the 2011 or 2018 Mars Scout might consist of a network of very small seismic landers, or that the ESA might succeed in gradually laying down a network. (The Network Science Mission would also seem an obvious choice for an international effort, and MEPAG has suggested just that.)

[nprev]

No seismometer on Phoenix or MSL; but there currently IS a plan to include one as part of a detechable package of geophysical instruments that will be left behind at the landing site by the ESA's ExoMars rover in 2011 -- the first of a hoped-for series of replacements for the Netlanders.  if the ESA actually funds ExoMars and it lands successfully before the Mars Scout (which are very big "ifs"), it might be able to pick up the thud.

Pity; Thor would be all the more beneficial if it could be used for gross internal geophysics as well.

Is it too late (or financially impossible) to add a seismometer-equipped Deep Space 2-type penetrometer on Phoenix to exploit Thor if the latter is approved, or has Phoenix PO system engineering decided to minimize mission risk by avoiding emulation of MPL as much as possible?

[edstrick]

Note that the Viking seismometer <VL-2> did not take seismic data continually, and only a fraction of the data returned was high-rate waveform data. High-rate data ate communication's bandwith to Earth, so they had a compressed mode, where they just measured the average signal amplitude and the number of "zero-crossings" the wave did during some short time interval. An even more compressed mode, I think, just measured average signal over some interval like a minute or more.

They took their highest quality data during low-wind night time periods and accumulated a fair amount of data. The conclusion was that the lander may have detected a signal similar to a terrestrial Richter 5'ish quake some couple hundred kilometers away, but they didn't have simultaneous meteorology data to prove that event wasn't an unusual quiet-period wind-gust. The lander thus was in an area with a seismicity similar to or less than a typical intra-plate area on Earth. No big surprise.

Since Viking, "network science" including seismic network, has always been a priority at Mars. The problem is that it has always been SECOND priority, so everything else flies and the geophysicists are left holding the bouquet. Pathfinder was the engineering proof-of-technology vehicle for a set of network landers, which had already been abandoned by the time the prototype flew... and so on...

[edstrick]

Oh.. and Phoenix is not expected to have an extended mission. I assume they will try to place the lander in an optimized hibernation mode with software that will let it try to revive after the CO2 snow blows away the next spring, assuming battery failure and the like, but it's rather less than likely we'll hear from it again.

But.. the Surveyors mostly survived at least one lunar night and 3 of 5 transmitted pictures on later days, despite abundant damage from thermal contraction. On the other hand, They tried to revive NEAR after a polar winter on the asteroid, but they never detected a signal.

[Guest_AlexBlackwell_*]

Laugh while you can, monkey boy.  Yesterday I had a protracted phone conversation with Paul Lucey at U-Hawaii, as a result of which I may start pushing the Europa penetrator idea again.

As long as you're thinking about "pushing," whatever that means, and assuming, of course, that has any effect, if it would not violate planetary protection requirements, maybe you could also convince Lucey to fly your ashes on that mission. Now that would be a proper way to commemorate the vital role you play in planetary exploration

[hal_9000]

opera mini test

[djellison]

Martian penetrators I can understand, a couple of hundred MPH impact - but places without an atmosphere? How do you go about bring the thing to a sensible impact?

Doug

[Bob Shaw]

Martian penetrators I can understand, a couple of hundred MPH impact - but places without an atmosphere?  How do you go about bring the thing to a sensible impact?

Doug

I think you could do something with a suitable sacrificial leading edge on a penetrator, intended to vapourise on impact and act as a shaped charge clearing the way for the main body (like a bunker-buster bomb). As for standing up to the forces involved in a large deceleration, well think of the Project HARP payloads developed by the not-so-lamented in certain quarters Gerald Bull - these didn't need to stand an instantaneous acceleration (whatever that might be) but instead one that took place over a number of microseconds, and manifestly they worked just fine. So, if artillery-launched payloads survive going up, then there's no reason for the opposite not to be possible. You'd probably be talking about a spinning high speed rod, much like Jerry Pournelle's 'Thor' kinetic blasters, but optimised for slowing down rather than just going bang.

Bob Shaw

[djellison]

Perhaps you would have to have some sort of small solid stage that takes the thing down to a much lower velocity at a few km altitude, and let it fall from there.

I wonder - would a Europa Impactor work at a Discovery budget ( unlikely I'd have thought ) or are we talking New Frontiers post-Juno ( with some small relay ability installed on Juno to handle it?)

Doug