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Questions tagged [comet]

Questions to do with celestial comets.

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How likely is it that a ternary cometary object forms from a binary one?

Binary comets, like 67P/Churyumov–Gerasimenko and MU69 Ultima Thule and at least a couple of others, have been observed. How likely would it be for a binary comet to again join with another object to ...
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Evidence of Water D/H Ratios of Kuiper Belt Comets

I was wondering, are the comets 67P/Churyumov-Gerasimenko and 103P/Hartley 2 the only Kuiper Belt comets to date that have their water D/H (deuterium-to-hydrogen) ratio measured?
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Puzzler; “who” are the members of this family of comet-visiting spacecraft?

In the video Once upon a time... Rosetta's grand finale (also in ESA Space Videos) mentioned in this answer there is a "family portrait" showing Rosetta along with previous comet-visiting spacecraft. ...
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What speed did the (interstellar) comet C/2017 U1 PANSTARRS have at perihelion?

C/2017 U1 PANSTARRS is a comet with an eccentricity of close to 1.2, so it is a strong candidate for having interstellar origin. It's perihelion was at 0.25 AU. What speed did it have relative to the ...
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Comet at Mars L1

If we placed a comet at Mars L1 point would we get a coma and tail that would add volatiles to the Martian atmosphere? I've also read comets create a bow shock with the solar wind, slowing it down, ...
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How long could a satellite orbit a comet without any control?

As a follow up of the comments here: Why was the Rosetta probe programmed to "auto shutoff" at the moment of hitting the surface? I'm fairly convince that a satellite cannot maintain an ...
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Did Rosetta improve on models of non-gravitational effects on comet 67P's orbit?

Question: Since the presence of the Rosetta spacecraft near comet 67P allowed for a detailed mass measurement, extremely precise position and velocity determinations, and physcal measurement and ...
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Could Rosetta find its way back to Earth?

Obviously, it's now an essentially inert artifact not going anywhere under its own thrust. The perihelion of 67P is about 20% larger than Earth's aphelion. Assuming its orbit is stable, neither the ...
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Why is Rosetta not going to hover or descend multiple times before crashing into 67P/Churyumov–Gerasimenko?

Currently Rosetta is on a free fall collision course with 67P/Churyumov–Gerasimenko. If I understand correctly the probe will send back data and pictures during the descent, and once it has crashed ...
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What forms of water ice have been observed and verified in the solar system?

The cool plot in this answer (from here) got me thinking about the more than sixteen distinct forms of ice, and how many of them have been actually seen to occur naturally in the solar system. There ...
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Why not use Halley's Comet as a probe?

Halley's Comet comes around every 75 years. From what I can gather on Wikipedia the comet is not spinning that fast, has a large elliptical orbit, and has been recorded since 240 BC returning on a ...
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Which are the main challenges for sample return mission from an asteroid and a comet?

The first sample return mission from a comet has been achieved by NASA's Stardust spacecraft, and the first sample return mission from an asteroid has been achieved by JAXA's Hayabusa spacecraft. What ...
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Why is comet deflection so hard (and how does a fusion rocket help)?

I just read an article arguing that we need very fast rockets for the deflection of comets, since we will probably detect them just several months before impact. So we need to hurry in order to pick ...
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What is different about the orbits of Pluto and the comets around the Sun? [closed]

What is different about the orbits of Pluto and the comets around the Sun?
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How could the gravitational pull of a comet affect spacecraft and astronauts landing on it?

When I researched the gravity on comets like on 67P/Churyumov-Gerasimenko's surface I found that it was several hundred thousand times weaker than on Earth source: www.esa.int/Our_Activities/...
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Could a planet, moon, or comet having a high concentration of a certain metal disrupt radio transmission?

I have been researching how metals affect radio transmission but have not found anything conclusive to the specific scope about planet density if it is mostly metal. One of the posts that I found ...
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How close can Rosetta come to the 67P/Churyumov-Gerasimenko comet?

ESA publishes quite a few images from the 67P comet, sent by Rosetta, from various distances away to collect as much as possible and as varied as possible. As I write, Rosetta is 6 Km away from the ...
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Why did Philae the comet lander bounce?

After Rosetta released the lander, it bounced several times upon hitting the comet's surface and its two harpoons did not deploy. Why did the Philae's grabbing mechanism fail?
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Valuable materials in Saturn rings and comets vs. Carbonaceous chondrites

Most common type of asteroids in inner solar system are carbonaceous chondrites while most common type of object in outer solar system are comets. Carbonaceous chondrites are very rich on carbon and ...
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How to use “HORIZONS” tool by NASA to get orientation of comet 67P/Churyumov-Gerasimenko axis?

I found this powerful online tool from NASA: http://ssd.jpl.nasa.gov/horizons.cgi#top It allows getting orbital data for the comet, but what I actually need is the orientation of the axis of the ...
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Philae Lander - Were drilling samples collected and analysed?

Were drilling samples taken by SD2 and analysed by Ptolemy, COSAC, and ÇIVA?
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May underestimation of 67P's mass have helped Philae?

It appears that we underestimated comet 67P's mass significantly (see What was known about 67P/C-G's mass before the arrival of Rosetta?) during the initial planning. I wonder if this ...
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What was known about 67P/C-G's mass before the arrival of Rosetta?

The determination of the mass of a celestial object is usually between hard and impossible unless one can observe something that orbits it. In the case of comet 67P/Churyumov–Gerasimenko, one of ...
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How close was Philae to escape velocity during its first bounce?

ESA indicates that the first bounce lasted two hours and reached a height of 1 km. With the extremely weak surface gravity and low escape velocity of the body (< 1 m/s), and other publicly ...
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Was the gravitational pull at Philae's landing site known prior to landing?

How well was the gravitational field of Philae's landing spot known before the landing? I am referring to the absolute value of the pull, the direction of pull, and the tidal forces.
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Is it feasible to put a comet into a Lagrangian point?

How feasible would it be to put a large comet, like the one that Philae landed on, into a Lagrangian point, or some other spot that would make it convenient & SAFE for mining, colonization, ...
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How important are Philae's harpoons?

There is currently a question as to if the harpoons fired, that is undergoing review. But I have to ask, how important are they? From what I've heard, a single leg touching the right spot could be a ...
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Did we expect Comet 67P/Churyumov-Gerasimenko to be dusty?

I just saw the pictures from Philae I was very surprised to see that the surface looks like it is covered in dust, not that much different than our moon. I personally was expecting it to be big ...
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If Philae lander had bounced off the comet and become uncontrollable, could we still have seen some of the descent photos?

In other words, are the photos transferred "live" to Rosetta or did they plan to transfer them after landing? (and would they have been lost had the landing failed) (yes, I am aware that "nice photos"...
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Did the tail of Siding Spring distort communication between Mars, and Earth?

This article writes to say There was an hour’s communication blackout during the comet’s fly-by ... What happened here? Did the tail of Siding Spring serve to block/distort communication between ...
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Could the Philae comet lander “hop”?

"Lander" is maybe not a good job description for the Rosetta sub probe Philae. I understand that there is no practically useful gravity there. Philae will try to hook itself onto the comet surface in ...
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Will kicked-up “dust” be a problem for Rosetta and lander Philae?

I see that escape velocity on 67P/Churyumov–Gerasimenko is 0.64 m/s. (Contrast Earth's 11,186 m/s.) With such light gravity I imagine any material kicked up would take hours to land, or orbit ...
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Rosetta's lander, Philae will “anchor” itself on Comet 67P. What level of control can we have over this?

Rosetta's lander, Philae is scheduled to land on Comet 67P in November 2014. This will involve use of "harpoon" to anchor itself to make sure Philae remains attached to the surface despite weak ...
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Can a single-apparition comet be used to propel a deep space probe outside of our solar system?

It seems this would be an economical way to explore anything beyond the heliopause, given that the probe would carry limited fuel.
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What is the smallest body that has sufficient gravity for another body to orbit it?

In the question Will Rosetta have to adjust its orbit around Chury due to the comet's coma and tails? and related answers it is implied that the Rosetta spacecraft will actually orbit 67P/...
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Where is Giotto now?

Launched in 1985, ESA's Giotto became the first spacecraft to visit a comet. Since then it has done at least some Earth flybys/slingshots to visit other comets. This image from the Wiki article ...
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Are any precautions in place to prevent loss of the Rosetta Lander the way Hayabusa's MINERVA was?

Back in 2005, Hayabusa carried a mini-rover 'MINERVA'. MINERVA was a Solar Powered entity designed to hop around on Itokawa, and capture images. Unfortunately (perhaps due to the time-lag) MINERVA was ...
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Is there a significant compositional difference between Oort Cloud comets and Kuiper Belt comets?

Comets can come from two sources, the Oort Cloud, or the Kuiper Belt. Is there a significant compositional difference between the two?
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Does any space program / government have an official stance on a procedure for handling collision-trajectory comets?

. ^ A Bad Idea. (You will now have a whole bunch of little asteroid pieces headed for you). Still, has any government or space program issued an official statement on what it would do if a large ...
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What was/is the Minor Body Exploration Forum?

I just finished reading the Japanese hard science fiction novel Ouroboros Wave. In the afterword, the author writes the following. For context, the book goes into quite a large amount of detail of ...
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Can the rovers on Mars see the comet flyby?

Within a few days Comet ISON is going to make a close flyby of Mars. Will the rovers on Mars have a chance to take a look at the comet as it approaches Mars?
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Would gold in space tend to collect in pockets like it does on Earth?

I was reading Does gold come from outer space?(BBC News). If the majority of gold on Earths surface does come from space would it tend to be equally distributed on comets and asteroids, or would tend ...
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Has water ever been confirmed on comets?

I am watching a documentary called "The Electric Comet," and the narrator claims that water has never been collected or detected from comets. This should be a surprising result as standard theory ...
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Will Rosetta have to adjust its orbit around Chury due to the comet's coma and tails?

ESA's Rosetta spacecraft is scheduled to orbit 67P/Churyumov–Gerasimenko after it reaches the comet by mid-2014: Rosetta's main objective is to rendezvous with, and enter orbit around, comet 67P/...
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Could a comet-trailing “scoop” be practical for mining?

It seems that most mining proposals involve landing on the body (blasting pieces of asteroids up from the surface for measurement has been proposed), would it be practical to exploit the volatile ...