InSight mission Options

[Paolo]

the GEMS Discovery finalist has been renamed InSight and now has its own website: http://insight.jpl.nasa.gov/

[Greg Hullender]

I was going to say I was amazed that we've reached the point where a Mars lander can be attempted on a Discovery budget. Then I found out that Pathfinder did it too: http://www.marsnews.com/missions/pathfinder/ That got me to wondering how much progress we've made in 20 years. I note that InSight should weigh about 350 kg--almost exactly the same as Pathfinder did.

A side-by-side comparison is a little tough, since InSight is about studying the interior of Mars while Pathfinder was focused on the surface. Also, the info on Insight is a little sketchy (from what I could find). A lot of it's derived from Phoenix, so that's a start I guess.

--Greg

[vjkane]

I was going to say I was amazed that we've reached the point where a Mars lander can be attempted on a Discovery budget.

Phoenix could fit into a Discovery budget only because the lander and instruments were mostly built. It turned out that the development team had to do a lot of testing and modification to the original design, but they had a solid starting place.

With the Phoenix lander a proven design, InSight can reuse it and hopefully fit within a Discovery budget.

[nprev]

Hmm. I read through the site & the poster, and saw no mention at all of any sort of cameras.

[Greg Hullender]

Oh I definitely love the idea of building new probes on proven platforms. I'm just wondering how much more advanced the instruments are now. I realize that's hard to quantify. Maybe just stats like GHz, megabytes, and bits-per-second would be enough. It just seemed that we're putting the same amount of mass on Mars as we did 20 years ago, but I'll bet we're getting 100x the data.

--Greg

[vjkane]

I read through the site & the poster, and saw no mention at all of any sort of cameras.

I believe the only camera is on the arm that deploys two of the instruments. It might also be able to be used for a panorama, but its primary use is to examine the area within reach and to determine where to place the seismometer and heat probe. This is a stripped down mission carrying only the instruments essential to the geophysical questions.

If they were to do an added capability for outreach, my vote would be to carry the duplicate of the Sojourner rover (with new CCDs for the cameras).

[Fran Ontanaya]

Is there a big difference between this mission and the canceled payload for the Exomars lander?

[djellison]

If they were to do an added capability for outreach, my vote would be to carry the duplicate of the Sojourner rover (with new CCDs for the cameras).

New CCD's means new backend electronics, new storage, new CPU, new radios.....basically, a new rover. It would cost a fortune. I adore Marie Curie - but bolting it onto InSight and deploying it 2001 style would be a bad idea. Moreover - without a stereo camera onboard InSight itself - you don't have the 3D terrain data on which to plan the driving.

[Phil Stooke]

One additional point about cameras... it is essential to know the exact location of a lander - the interpretation of seismic and heat flow data will be very much tied in with knowing what it landed on. Phoenix was located with HiRISE images but we can't guarantee the availability of images with that resolution in 2016. So precise location will depend, at least as a back-up, on locating the lander with respect to horizon features. So some degree of ability to survey the site will be necessary to guarantee the quality of the science. For Phoenix, the RAC camera on the arm was not used as a site-mapping instrument (except underneath the lander), but it could have been, if necessary.

Phil

[vjkane]

I adore Marie Curie - but bolting it onto InSight and deploying it 2001 style would be a bad idea.

And there would be the cost of requalifying now 'ancient' parts for flight for which spares may be hard to find. So I mentioned it as a what if day dream, not as a realistic proposal.

Also, I've heard that the goal is to put the lander down in flat, boring landscape to ensure a safe landing, so there is likely to be relatively little to see or for a small rover to poke around in. Still, it would have been nice for Marie Curie to eventually make it to Mars.

As for the question of how InSight compares to the cancelled ExoMars geophysical station, a quick search on Google didn't bring up the latter's instrument list. However, as I remember, it was fairly extensive, more so than InSight. InSight is a tightly focused proposal that does less than most proposals for Mars geophysical stations/networks. That focus gives probably gives it a better shot at flying than previous proposals, none of which flew.

[vjkane]

One additional point about cameras... it is essential to know the exact location of a lander - the interpretation of seismic and heat flow data will be very much tied in with knowing what it landed on.

I haven't seen this discussed, but they may have a descent camera to meet this need. Phoenix carried a descent camera that wasn't used because, if memory serves me correctly, software issues discovered in flight. The InSight mission could make the necessary changes.

[Greg Hullender]

Here's a completely different question: to get earthquake locations, don't you need three, separated seismic stations? Without location, you don't really have magnitude, do you? What will InSight be able to tell us?

--Greg

[djellison]

You don't need a descent imager to exactly locate a spacecraft on the surface of Mars. We have HiRISE for that.

[Phil Stooke]

But we may not have it in 2016. Almost certainly it will land in an area of HiRISE coverage, but surface images may still be needed, as a backup if there is no working HiRISE, to match the site with the orbital images. Without images the best we can expect to locate it would be within 1 or 2 km, but it's still useful to know if you are on a small crater's ejecta deposit, or on one side or the other of a terrain boundary or sediment deposit.

I wondered about a descent camera as well. That would be useful, indeed. I seem to recall the problem last time was about moving the descent camera data into the spacecraft computer during a critical time. Hopefully the next descent camera will have its own memory to make that data transfer unnecessary.

Phil

[Drkskywxlt]

Here's a completely different question: to get earthquake locations, don't you need three, separated seismic stations? Without location, you don't really have magnitude, do you? What will InSight be able to tell us?

--Greg

All of the previous Mars network mission concepts, which are focused on interior structure as well, rely on multiple stations so they can triangulate locations in the interior and get a better 3-D picture of the structure. From what I've been told and heard at conferences, InSight will STRONGLY rely on modeling to validate it's measurements. InSight seems to have the inside track as the low-risk option of the 3 finalists, but they need to make the case that their results will be robust when they're depending on modeling to interpret their signal.