Very funny, Alex. If it makes anyone feel better, I don't have anything to do with planning MOI.

jmknapp has performed a valuable public service by highlighting that those three kernels produce significant orbital timing changes; I hadn't appreciated that the MOI performance could induce that large a change, but now we're prepared. We weren't given any context about what those kernels might mean -- they just showed up on the NAIF website. They may be for training purposes, or they may be physically realistic.

That result sounds pretty close to ours, so I'd say your code is working well. Those kernels just appeared on the NAIF website and I don't know what sort of burn performance differences they represent; it would surprise me if plausible burn variations would change the orbit timing so much.

That's true, we haven't completed that. Our MRO, MSL and LRO work has cut into the hobby time I used to make the B&W mosaics, and the color mosaics are much more labor-intensive to make.

http://www.arcscience.com/face.htm has a colorized Mars map, but it appears to be a commercial product.

We were doing this planning several weeks ago, so the kernel I used was from mid-January. In those kernels, we were near periapsis at 6:00 UTC. Looks like we're looking at some replanning if the MOI performance makes this much difference. I would try rerunning with ideal and see what that looks like.

BTW, what software are you using for this?

I think your software is confused, or ours is. What SPICE kernel are you using?

Try looking (hint, hint) closer to 6:00 UTC.

Because it is, pretty much; at least as closely as an R-C Cassegrain system can be. As for your point about HiRISE having better SNR; that's certainly true, although the TDI will degrade the MTF at Nyquist, especially if the spacecraft attitude control has any jitter in it at all. I stand by my original assertion: HiRISE will have better image quality than MOC, but not by as much as a simple ratio of their ground sample distance would suggest.

No, just look at the diffraction limit. HiRISE has a 50 cm aperture and is sampling 30 cm from 300 km. MOC has a 35 cm aperture and is sampling 140 cm from 400 km. All other things being equal, you can't get 3.5x better resolution at the same image quality by increasing the aperture by less than 2x. (HiRISE has 12 micron pixels and MOC 13 micron, but that only helps HiRISE a little.) HiRISE will have better image quality than MOC, certainly, but not 3.5x better; it's not physically possible.

For starters, the maximum data rate that is being assumed is more like 4 Mbps. For an 8-hour pass, the s/c is only in Earth view about half the time, so two passes a day at 4 Mbps would return about 115 Gbits assuming no time to lock up, no retransmits, etc. So the graph seems roughly correct.

But the max data rate is only doable when the Earth-Mars distance supports it, which is why the graph goes up and down. And yes, at the low data rate periods you shouldn't expect to see many full-size max res images from HiRISE.

I suspect that most HiRISE images will be summed down from the maximum resolution, both to save volume and because the HiRISE MTF may not be all that great at full-res.

Some of those are astonishingly good. I wonder if someone with a real Web site could host these in a more browsable form.




Tough question. Since we've imaged such a small fraction of the planet at MOC resolution there could be another major discovery in an image we just took today. In terms of papers in SCIENCE, on the other hand, the discovery rate has tailed off, but that might be in part because of the science analysts also working on other stuff (MRO, MSL, etc.) I don't think you could find very many LPSC abstracts about Mars that didn't use MOC data, though.

Interesting stuff. Such a spacecraft at Jupiter would have been able to concentrate on particles and fields stuff, and
left Galileo free to concentrate on imaging and remote sensing, instead of the overly-complex,
spun/despun section, do-everything-poorly design it was ultimately stuck with.

Of course, the money wasn't there to do this mission. It's hard to get a straight answer about the ultimate scientific return
of the Galileo mission. Certainly it didn't provide the sort of eye candy that Cassini has; I was recently looking through
a coffee-table book about the Galileo mission (MOONS OF JUPITER by Kristin Leutwyler) and was struck at how poor
most of the imaging was. Obviously the mission was terribly constrained by the antenna failure, but all the happy talk about
how well mission objectives were recovered seems hard to support with the end product.

I'm sure there's a fascinating book to be written about the Galileo mission (infighting between Ames and JPL, all of the delays,
all of the in-flight problems) but I've not seen it yet.

http://pds-rings.seti.org/volumes/COISS_00...port/index.html looks useful if the PDS volumes don't answer your questions, though the tables are all PDF files and would be painful to extract.

For Galileo, the GO_0001 CD is supposed to have this stuff; I haven't looked.

Your post implies that spending more money decreases risk. It ain't necessarily so, at least not at all times and not linearly. There have been plenty of failures in programs where few expenses were spared: Hubble and Galileo, just to name two.

The MPL failure had little or nothing to do with parachute or thruster testing, and it's really hard to estimate how much more money would have been needed to find the problem. If a couple of people had been thinking just a little harder, a few more lines of code would have been written and there's a good chance we wouldn't be using MPL as a negative example.

Lexan isn't a good choice due to outgassing and optical quality. It's fairly hard to make a cover that doesn't screw up optical performance, especially for a fixed-focus system.
That said, the Galileo SSI did have a transparent cover (I'm guessing it was glass). All of the systems I've worked on (MOC 1&2, THEMIS, CTX, MARCI 98&05) had no covers at all -- we were too mass-constrained.

Seems like the technical problems are the fault of Orbital or their subs, not the science team or the instrument providers. My guess is it'll be a while before Orbital gets picked to do a planetary mission again.

I don't know much about the economics of IMAX in general or of non-commercial IMAX theaters like those at museums. The commercial theaters have 35mm IMAX blowups of Hollywood movies competing with science productions, and that probably makes science a tough sell. I suspect that showing ROVING MARS is fairly costly for a museum theater, but I don't know how much. And I understand that even running an IMAX theater is pretty expensive; $150K just for annual maintenance.

Of course, in San Diego the only IMAX option we have is the dome at the Fleet Space Theater, which makes watching most IMAX films a painful experience anyway, IMHO.
But it's surprising that the California Science Center in LA isn't getting it either.
Maybe the release was timed too closely with MAGNIFICENT DESOLATION.

HiRISE has an IFOV of 1 microradian, so the pixel scale is the distance times 1e-6.
MRO is probably about 7 million km out right now (the simulations on the MRO site don't show the range) so that's 7 km/pixel. Mars is about 7000 km in diameter, so that's about 1000 pixels.

Of course, there are no plans to take such images that I'm aware of. The opnav camera is pointed in a direction almost 180 degrees away from the rest of the science instruments.

Actually, the Mars Observer/MGS data architecture is amazingly clean -- each instrument gets its own allocation of downlink rate (most of it goes to MOC) and there's no need to adjudicate downlink usage; it's all pre-allocated. There's no waste because everyone uses their entire allocation (in the MGS case we have a lot of planning and sequencing software that insures this.)

Odyssey and MRO use "APIDs" -- ways of prioritizing how all the various data products are prioritized and sent down. It may have some benefits, but it also requires more coordination between data producers. Both systems work but the MGS scheme is simpler.

Odyssey can send more data simply because it has more memory -- its RAD6000 has 128 MB whereas MOC has 12 MB -- and its downlink is faster (about 128Kbits/sec max, compared to MGS's ~80 Kbps.)

There were two factors. First, Odyssey has more a lot more memory onboard for UHF data, and it can send it to Earth 2-3x faster than MGS. So Odyssey was much preferred for UHF passes. Also, when MOC is used for UHF data it can't do much else, whereas the Odyssey science instruments can carry on pretty much normally through a UHF pass.

Second, the design of the Mars Relay on MGS didn't include any handshaking, so a small amount of data was probably dropped every 16 seconds, and this might have impacted image processing. I'm not really sure how the MER UHF handled the lack of handshaking, if at all.

You can read a lot more info about the MR on the MSSS website, http://www.msss.com/mars_images/mars_relay/mer/



That was Elsa Jensen, the MOC operations supervisor at MSSS. She got a credit in Squyres' book and I didn't.

We took global maps on the landing orbit for both rovers. See http://www.msss.com/mars_images/moc/2004/01/07/
(doesn't look like we did a similar release for MER-B.)

Wow, thanks Doug! And thanks also for including the time indices so I didn't have to listen to all of the commentary. (sorry Donna)

Frankly, what I said seems clearer than I remember it being -- I'm not sure why the JPL people continued to be in suspense as much as they did.

It's funny, we had NASA TV on in San Diego but with the volume turned down, and Wayne Lee's commentary wasn't on the voice loop we were on, so we really didn't have much sense of what the mood was at JPL. After they got the tones back the loop went nuts, so much so that I couldn't get a word in edgewise to indicate that we were pushing the UHF data back to JPL -- hence my "I assume you see your data" after it had come up on their screens.

If I had heard him, I would have asked the flight director to tell Wayne Lee I wasn't Malin...

I did get a call about a half hour after this point saying that our processing software had incorrectly time-tagged the EDL data, so I was in the office for a few hours after that making sure the next MGS pass would have good time tags. (It turned out the problem was due to the non-standard way we were processing the EDL data so as to tell how much we were getting in as close to real-time as possible.)

Yeah, sorry about that. For the MER-B landing we tried to pre-script our report for more clarity, but they got the tones quickly so it didn't matter. I don't think many of the MER people understood how the MGS link was going to tell them and on what timescale.

Aviation Week got it mostly right, but identified me as Mike Malin. Grrr.

"At 8:44 p.m. Michael Malin of MGS reported that the satellite had received more than 240 kilobytes of UHF data--so much data that most of it must have come from the surface. But from the anxious looks on controllers' faces it appeared no one heard him. Malin made more increasingly positive reports over the next several minutes that also seemed to fall on deaf ears."

From your blog:

"They spent several minutes building up the tension that surrounded Spirit's landing, and the horrible 10 minutes of silence that followed it."

I don't suppose they left in any of the voice traffic from MSSS (call sign "MGS MOC") reporting during that period (in admittedly cryptic terms) that we had enough data from the UHF pass that the rover had to have survived the landing? I feel a bit cheated out of my place in history by JPL's failure to understand what I was saying, and I've never seen a transcript or heard a recording that included that traffic. Oh well

It's standard JPL practice to design and test things for 3x the expected mission life. So they planned for a 90-day mission but had test data that said they could last for 270 days if conditions were as expected.

Clearly the NH payload is much more capable than Voyager's. That said, I don't think NH would have flown if Voyager 1 had visited Pluto, assuming that it had worked as well as Voyager 2 did at Neptune. We would have 1 km resolution visible color images of the illuminated faces of Pluto/Charon and probably some occultation data (I'm not sure that IRIS could have gotten anything useful.) That would have made spending the NH budget on " just another flyby" a pretty hard sell.

Very true. You might be better off using JPL Horizons, which can generate ephemeris information on MRO -- http://ssd.jpl.nasa.gov/horizons.html

Of course, you can only generate heliocentric states with it, so you can't directly look at velocities in the Mars frame.