Comet observation from Mars, comets close encounters to Mars in 2013 and 2014 Options

[MaG]

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.

[fredk]

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!

[stevesliva]

but Giotto survived the Halley encounter at about 600 km

Mostly. With a Whipple shield.

[SFJCody]

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.

[SteveM]

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.

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

[SFJCody]

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.