Is there is any possibility to observe comets in near future from surface of Mars and/or from Mars orbiters. Which types of instruments are possible to use?

For example (http://ssd.jpl.nasa.gov/horizons.cgi - position Mars 0deg Longitude, 5deg south Latitude, time UTC):
1) Comet C/2012 S1 (ISON)
2013-Oct-01 17:19UTC RA 23 07 44.73 DE +69 27 46.0 MAG 2.93 r 1.637007919902 delta 0.07246306543080

So there is relativly very close encounter in October 2013, about 11 million km from Mars..

2) Comet C/2013 A1 (Sidding Spring)
2014-Oct-19 20:59UTC RA 10 49 50.64 DE -60 38 09.5 MAG -8.29 r 1.401218071277 delta 0.00070643344409

There is still maybe not so precise orbit BUT, there is ONLY about 105 000 km (65 000 miles) encounter from Mars.
Especially the second comet, if this orbit will be OK, is very interesting target to observe.

The sight from mars on C/2013 A1 should be spectacular! I tried to simulate it with Celestia, its appearance in the sky should be huge!

I think it's a safe bet that any extremely bright comet will get imaged. Dimmer objects will likely not be visible and at some brightness the attempt probably won't be made.

Update.

"Today, at the ISON-NM observatory, new astrometric measurements were received for this comet. Based on the existing measurements, more accurate orbital elements were calculated. The results of the second calculation for the close approach show that the comet might pass just 41,000 km (0.000276 a.u.) from the planet’s centre, that is less than 37,000 km from its surface!"

From that site:

I'm thinking this is unlikely to be a threat to the rovers and probably not to orbiters either.

Less than the apoapsis for India's Mars Orbiter Mission (80,000km).

I'm still missing more excitement about this.
If flyby distance will be really around ~50 000 kilometers, than this event is comparable to the encounter of Halley comet with so called Halley armada.
We can have up to five orbiters with superior instruments which can probe Hale Bopp class cometary nucleus with cameras and spectrometers in multiple wavelengths.
Some orbiters (MEx, MAVEN, Mangalyaan) have instruments for direct examination of atoms, ions and another particles.
We have flyby worth of one billion dollars for free!

Thing is, none of the orbiters have been designed for a comet encounter. I'm a little worried about sandblasting, but also wondering how much ACS fuel expenditure would be needed to do a good job of observation; every burn shortens their operational lifetimes, and this thing will be really moving at closest approach.

I dunno; as the oldest orbiter, might be a good job for MODY. MRO could do something amazing, no question, but doubt that the mission's management would go for more than a set or two of obs, if that.

All that said: Yeah, I'm actually pretty pumped!!!

Yes, it will not be easy. But I think that all teams, which have spacecrafts around Mars, are very experienced and they will handle it.
BTW, It's even more fantastic. It can be our first close observation of long period comet visiting us directly from Oort cloud!

How long is MAVEN's commissioning phase anyway? Hopefully a month is long enough to get ready and calibrated.

This whole thing reminds me of Shoemaker-Levy and Galileo all over again, but multiplied many times; including ISON it's less than one Mars year between two close comet encounters; looks like these sorts of coincidences aren't limited to Earth...

Meh. The wonder of statistics (which are tedious to compute, but always quite fascinating to grasp).

Both cameras with any resolution on MRO are linescan anyway, so the target moving is a feature, not a bug. It may only be necessary to repoint the s/c, which can be done on the reaction wheels with very little fuel usage. Even if scanning is needed, the wheels can likely do it. A more substantive problem is that the resolution isn't that great -- 125x worse than what we get on Mars (750 meters/pixel for CTX, around 40 m/pxl for HiRISE.)

That said, this is still more than 1.5 years away and the ephemeris and even the size of the comet are uncertain, so detailed planning is premature.

We've made (and survived) many comet encounters with several spacecraft, at distances of several hundred km down to a couple hundred km (Deep Impact, Stardust, etc). Those were smaller comets, but Giotto survived the Halley encounter at about 600 km. Of course those missions were designed for comet encounters, not for Mars orbit.

My guess, based on flux conservation, is that the density of particles in the coma drops like roughly the inverse square of the distance from the coma nucleus. So even if C/2013 A1 turns out to be Halley class, at a distance of 40 000 km, the density of particles would be thousands of times lower than what Giotto experienced. The latest ephemeris gives 7th magnitude at its brightest from earth, so that sounds like it isn't Halley class, which means the particle density would be even lower. On the other hand, the encounter velocity will be considerably higher for C/2013 A1 than for previous comet encounters, so any dust hits would have a greater impact.

Of course this is still early days, and brightness estimates will be improved. Most crucially, as mcaplinger said, orbital elements will be improved. The big question now is what is the uncertainty in the close-approach Mars distance? The blog quoted above stated that the comet "might pass just 41,000 km... from the planet’s centre". Is that a lower limit? What's the upper limit? That would give us a better sense of what the Mars close-approach distance will be.

Anyway, based on these numbers, I'd expect no real concern for the orbiters, and even less for the rovers.

And I too can't wait for this encounter!

Looking forward to those Kodak moment pictures this site is famous for!! Even Hubble might snap some compelling images during the passage?

Maybe too much to hope for but possibly there is some fragmentation close to the sun to make an even better show at Mars.

And for those wondering about an impact, remember: Mars is an even smaller target than Earth, in a very large solar system!
I expect this to go rather like it did with Apophis; the probability of a collision will go up as predictions get more refined, and than it will drop when the error ellipse no longer includes the planet. See here: http://en.wikipedia.org/wiki/File:Apophis_ellipse.svg

In other words, the news might get worse (for Mars's health) before it gets better. Merely passing through the coma/tail seems far more likely.

Well, based on the earlier observations (thru 20 Feb, giving nominal 105000 km close approach) JPL estimated miss distance could be anywhere from 0 to 1.18 million km with a 3-sigma time uncertainty of 260 minutes. If I'm reading it right the 3-sigma error ellipse at close approach is 735000x139000 km across, with the intersection around the 1-sigma contour... so it will take a bit more refining indeed! Of course,we have some time; that link should continue to be updated whenever they update the orbit.

Mostly. With a Whipple shield.

http://tech.groups.yahoo.com/group/mpml/message/28195

Some new astrometric data has been collected. There should be a recalculation of the closest approach distance from Leonid Elenin soon.

A brief discussion of imaging prospects with MRO in this S+T story.

Mont Carlo solution of approach to Mars at Minor Planets Mailing List .

I just find it extraordinary that an object of 10 to 50km diameter has a non-negligible possibility of hitting any of the terrestrial planets. The very idea seems in complete opposition to the principle of mediocrity. This thing would dig a crater at least twice as big as Copernicus on the Moon, and even that is so old that it predates the evolution of complex life on Earth. That we should be here at just the right time to see something like this slam into our neighbour just strikes me as astronomically unlikely.

Playing around with the current trajectory (from MPEC 2013-E06 issued a few hours ago) in Celestia:

The nucleus of C/ 2013 A1 rises above the local horizon at Curiosity at around 19:30:42 UTC @ 334 deg. (NNW) when the comet is 54,387 km from the rover. That's a couple of minutes after closest approach. This is in the late afternoon for the rover. The comet continues to rise in the northern sky. When the comet is 100,000 km from the landing site at 19:53:40, the nucleus is 46.5 degrees above the horizon at an azimuth of 344 deg. When the sun sets at 20:26:49 UTC, the comet's nucleus is 202,840 km away (AZ=338 deg, ALT=61 deg). The nucleus sets in the western sky on October 20 @ 02:12:08 UTC when it is at at distance of 1,359,200 km.

Opportunity gets to look at the comet on the inbound leg with the comet setting at 19:31:53 UTC @ 28.5 (NNE) when the comet is 55,283 km from the rover. That's three minutes after closest approach during mid-morning for Oppy. At 19:26:44 UTC, the nucleus will make its closest pass to Opportunity when it is 52,539 km away (AZ=20.75 deg, ALT=16.5 deg). When the sun rises at 17:48:17 UTC, the comet's nucleus will be 334,450 km away (AZ=56.9 deg, ALT=87.3333 deg). The comet rises in the eastern sky on October 19 at 11:34:19 UTC (middle of the night) when it is 1,590,000 km away. It rises again on October 20 at 23:45:26 UTC (ENE) when the comet is 867,230 km from Oppy.

Closest approach to Mars according to JPL Horizons data ported into Celestia is on October 19, 2014 @ 19:27:37 UTC. The distance from the surface is 50,130 km. The Comets C/A distance to Phobos is 53,326 km and to Deimos it's 51,618 km. From Mars' perspective, the comet is inbound over the planet's dawn hemisphere and outbound over its dusk hemisphere.

Click to view attachment

Shoemaker-Levy 9 passed within 70,000 km of the center of Jupiter and collided with the planet. Even in the past 20 years there is another case of a kilometer scale object coming this close to a planet. I think that the rate of large impacts at Mars and beyond may be a great deal higher than people had previously assumed.

This thing is a planet killer. If it hit Mars, it would make at least a Gale Crater size hole.

The other comets to be well imaged are all short period comets with an aphelion of under 6 AU. C/2013 A1 comes from the Oort cloud, so it may look significantly different from the others. Hopefully HiRISE can get a 40m/px images of this thing, and CRISM can detect the minerals on the surface. THEMIS may be able to resolve the nucleus in the thermal IR and measure its temperature. MAVEN can do fields and particles science on the coma. Mars Express may also get low resolution images, spectra and particles data.

Yes, that's a good point. First ever Oort object to be seen even remotely close up. Observations from Mars surface/orbit should be planned for basically that reason alone, even ignoring the visuals....

The VEGAs actually fared less well in some respects, even though they were 10 times further out than Giotto (maybe encountered a jet?)
http://www.lpl.arizona.edu/~rlorenz/solararraydamage.pdf

Belatedly realised that what I said above was pretty silly. Was trying to think of young (<100Ma) craters in the inner solar system that are around 200km in diameter or greater, and for some reason the word 'Chicxulub' never occurred to me...

Just because it's pretty

Click to view attachment

Checked the flyby on NASA's Horizons and found that the elongation of the comet from the Sun remains in the range 84° to 90° throughout the encounter.

According to the current model, Mars will never be "downstream" from the comet so won't be as strongly impacted by the outflow of the coma as it would be if it passed directly through the tail.

Steve M

"This thing is a planet killer." (Don1)

It might not kill Mars but it might be a rover killer. Depending on location it could darken the skies long enough to really hurt Opportunity. But the chance of that happening is very small - luckily for us rover-lovers.

Phil

The jpl database now lists the "nominal" close-approach distance at a bit over 50 000 km. But they list the "maximum" distance as over 300 000 km. I can see no definition for the "maximum" distance, but elsewhere they refer to 1-sigma uncertainties. So if that "maximum" distance corresponds to the 1-sigma upper limit, then it will be a much better indication of the likely close-approach distance than the "nominal" value, if the errors used in the calculations aren't overestimated. In fact, for a gaussian error distribution, the odds are something like 32% that the actual value will be greater than 300 000 km!

The "minimum" distance is listed as zero, which presumably means the error ellipse still intersects Mars. But the area of Mars is an incredibly tiny fraction of the area of a 300 000 km (or 600 000 km?) error ellipse, so the chance of collision is extremely small.


That's interesting - it would mean that the comet would be viewed perpendicularly to the tail throughout the encounter, which is great news for getting good tail views (or at least views that aren't very foreshortened). But if the error ellipse still includes Mars, the comet could as easily be on one side of the planet as the other during encounter. It could also be sunwards or outwards, presumably by as much as something like the 1-sigma value, 300 000 km. So all options still seem to be open. It looks like we'll need lots more observations before we can pin down the encounter specifics.

Per http://ssd.jpl.nasa.gov/?horizons_doc#ca the Max/Min values are "formal 3 standard-deviations with linearized covariance mapping" so pretty much inclusive given the HORIZONS error model.

For fun and knowing as above that it's probably entirely wrong, and is certainly not right given the unknowns, here's how the current nominal orbit of C/2013 A1 could look from MSL's position.
Click to view attachment Click to view attachment

As far as I have read, nobody else said something about size of nucleus, only Leonid Elenin. I think, it's very hard to predict it now, but Jakub Cerny (my friend) wrote an article in czech, that the size of nucleus must be much smaller. For example if you remember comet Hale-Bopp, it was much much brighter in the same distance. And we hope, that it's nucleus is 40 +/- 20 km. So comet's Sidding Spring nucleus is maybe much smaller, Jakub said about 3 to 8 km (derived from their nucleus brightness).

I hope there will be no collision in the future, but if so, even 5 km nucleus is very much. There is no doubt..

Thank you for information about possibilities of imaging by orbiters and rovers.

To SFJCody's interesting thoughts about the unlikelihood of seeing a very large impact in our lifetime, I think the key points are:

1) Near misses, if you define them as having about 250x the cross section of the planet, will happen almost 250x more often than actual events. If Chicxulub events occur every 50 million years at Earth, there will a Chicxulub-sized near miss every 200K years.

2) If you count four bodies (Venus, Earth, the Moon, and Mars) as targets of interest, you divide that roughly by four, so every 50K years.

3) The martian cratering rate, per unit surface area, is about 2x the Moon's. But for near misses of a given distance, surface area is irrelevant, and we get a martian rate of about 8x the Moon's. So for Mars alone, we expect one such event every 25K years.

4) The pass is not known to be this close and we'd have to integrate over the possible trajectories to rate it fairly, but this may be considerably further, and so we get further reduction.

5) A generalization/extension of (3): There's a logical fallacy of taking the most unlikely thing that you observe/forecast and noting how weird it is that it happen. What was the probability that you would receive the phone number you were assigned at random? Near zero for that precise number, but the probability that you would get A number about which you could make that comment is near unity.

The solar system allows for many weird catastrophic events that could happen, and cumulatively the probability of one of them happening is much higher than the probability of any one of them. We could have seen a collision form Saturn's rings, but we didn't. We could have seen volcanic activity repave Venus's whole surface during our lifetimes but we didn't. We could be seeing a nearby red giant go supernova but we're not.

Given that the Mars event is looking like a once-every-few-thousand-years event and there are innumerable comparably striking (no pun intended) events we could make the same comment about, it doesn't seem so strange that we're seeing one of them.

Thanks for pointing out that documentation, Greenish. So 3-sigma means that the odds are only about 0.3% for the actual value to be greater than 300 000 km. This assumes gaussian errors and that the linearized error propagation is accurate.

The view from Earth may offer an interesting twist; assuming that the coma is extensive enough, Mars itself may project its shadow on it.
In addition, a particle in the coma moving at 56 km/s would clear the shadow in, say, 100 sec so small enough particles should cool down considerably
during that time. Thermal infrared, anyone?

Even if the nucleus of C/ 2013 A1 doesn't hit Mars, it will still have an effect on the Martian atmosphere. The coma and maybe the tail will cause a great meteor storm on the Martian sky. Most of the meteors would be very tiny specks of dust, but they would still be visible as shooting stars.

Meteor showers on Earth are caused by trails of comets long past, so the approach of an actual cometary coma must be a much more significant event in this sense.

I am doubting the 50 km size as well, though for a different reason. While most comets we've seen upclose are very dark, they have also been close to the sun repeatedly. This is likely this comet's first trip close to the sun and it probably retains a significant amount of ice on its surface. So it probably much higher albedo. Assuming, an albedo of 0.5, its diameter should be around 16 km. Assuming a diameter close to 1, its diameter would be closer to 10 km.

http://neo.jpl.nasa.gov/news/news179.html
Comet 2013 A1 (Siding Spring) will make a very close approach to Mars in October 2014
NASA/JPL Near-Earth Object Program Office, March 5, 2013

Also includes illustration of brightness curve.

October 2014 will be well into southern spring, around solar longitude 210 or 220 degrees, a time when tau at Oppy is typically getting up around 0.8 or 0.9. So unfortunately opacity will limit visibility of the tail and coma somewhat. On the other hand, Oppy won't be in the dead of winter and so may have power to do limited nighttime observations. I mention Oppy because her pancam L1 appears to be the fastest optical system on the ground. Of course if the comet gets insanely bright, opacity and optics won't matter so much...

I wonder if it would be worth having Curiosity try to shoot a minute of 720P video near the zenith at the time of maximum local exposure to the coma. Success or failure to see bright enough meteors would be informative. It could be a unique look at a super meteor storm.

I'm not sure the video-capable Mastcam is well-suited for catching meteors on account of having fairly narrow FOV. Navcam would be a better candidate, but unfortunately it can't capture high frame rates.

MAHLI is video capable and has relatively large FOV (39.4°×31.1°). It's not so big as the NavCam's FOV (45°), but it's bigger than FOV of the M-34 (20°×15°).

The more important thing is the overall camera system sensitivity (ie optical system speed plus CCD sensitivity). MH (and presumably MC, and definitely navcam) are quite slow, as the recent night sky imaging demonstrated. So if you see nothing, you can't be sure that you didn't miss many meteors below your limit.

It might be worthwhile, though. We'd need to estimate the faintest meteor that MH could detect.

Press release about Siding Spring:
http://science.nasa.gov/science-news/scien...6mar_marscomet/

Looks like MAVEN won't be fully commissioned until 2 weeks after CA, but there could be lingering effects. Everything in orbit and on the surface should get a show for the cameras. First I have heard about the aurora possibility.


The odds are a 1 in 2000 chance of impact at this point.

The nucleus has shrunk a lot. 1-3 km now? It was "upto" 50km before.

Don't confuse estimates based on constraints with actual measurements. The 50km upper limit was based on early albedo predictions; as the comet gets closer these will be refined based on observations.

In other words, the nucleus didn't shrink from 50km to 1-3km.

If Mars ploughs through the coma and/or tail SAM may do some great measurements as well. Would be interesting to see how atmospheric composition changes over time if at all.

Tails/comas are extremely tenuous. I'd be very surprized if a pass would leave any measurable effect, even in Mars's thin atmosphere.

The total amount of gas the comet might add could be a few litres of gas at ordinary atmospheric pressure at Mars - in short any addition will most likely be unmeasurable.
That said without considering the effect on one quite unlikely collision - if that happens the effect could be dramatic - possibly even result in a continuous rewriting of the textbooks for the martian atmosphere over the foreseeable future.

What's interesting is that NASA seem to be looking into the option of having any or perhaps all orbiters having a look at the comet, since the comet might be passing as close as a few 100 000 of kilometres and even closer, this could turn out to be one opportunity to get a comet exploration mission for free. =)

OK I need some expertise about spacecraft methane detection: a recent Indian news report claims that the Indian Mars Orbiter may be delayed from this year's launch window because the comet may affect the operation of one of its science instruments, the methane sensor. It quote an un-named scientist saying that "Most comets have methane, and there is a good chance that our MSN payload (methane sensor) may confuse the methane it detects from the comet as that of Mars and transmit wrong data. Such data will mislead us. Even NASA is wary. "

Somehow I think that this should never been a problem - in fact that little spacecraft is in such a high elliptical orbit that it is in the prime position to make observations of the comet tail, so it seems strange that the Indians think that there's a data contamination problem - they could just delay the instrument's observations if this really is a problem, which again I doubt (or just record the before and after comet passage data for comparison). Hmm.... does that mean something else is going on with the testing of the spacecraft?

Can any expert on trace gases shed some light on the credibility of this claim? Thanks!