31

But if some space debris comes on its way or any of the extra planetary objects comes on its way then how it changes its path? Not only won't Voyager 2 change it's path, it can't change it's path. Suppose you drop your cellphone from the top of a tall building. Your cellphone is going to fall and hit the ground, hard. Your cellphone has no sensors to ...


28

No, 75 meters is not exceptionally close — several satellites show predicted passages that close or closer every single week of the year. But it is close enough to potentially appear in the top 10 list of satellite conjunctions for the week: http://celestrak.com/cgi-bin/searchSOCRATES.pl?IDENT=NAME&NAME_TEXT1=&NAME_TEXT2=&ORDER=MINRANGE&MAX=...


27

Exceptionally rare? No. Uncommon, well, yes. From what I can recall, these happened about once every 10 years per satellite for the constellation of satellites I worked with, at least, prior to doing a collision avoidance maneuver. That of course included debris/ satellite close approaches. Of course, I note that the two you listed are both live satellites,...


27

Space is almost completely empty. The voyager probes are exceedingly unlikely to collide with anything (as demonstrated here: What is the possibility of Voyager 1/2 colliding with matter (Asteroids or planetoids) present in space?) larger than a mote of dust. If they did collide with anything at 15 km/s, then it slowing them down would be the least of their ...


26

No spacecraft has been yet lost to the asteroid belt. In fact, we have the opposite example of missing an asteroid when it was even targeted, like was the case with MINERVA lander of the JAXA's Hayabusa deep space probe, missing the 25143 Itokawa asteroid. Why haven't we lost any spacecraft due to collision with asteroids in the asteroid belt is also pretty ...


23

There's no real distinction once you're in orbit; a northbound LEO orbit at a given longitude at a given time is a southbound orbit at nearly the opposite longitude 45 minutes later. The rotation of the Earth brings any chosen launch site under the ground track of every polar-orbit satellite, in both directions, daily. Therefore, the choice of northerly or ...


23

Spacecraft rely on information from earth to avoid space debris, they don't have instruments for scanning and detecting debris. There's a few reasons for this: Power: most spacecraft don't have enough electrical power to run a radar powerful enough to detect small debris far enough away to matter Weight: in order to be useful for detecting debris the radar ...


21

The Voyager probes are outside the Kuiper belt now, and have a very long way to go before entering the Oort cloud. They are now in a place that is almost completely devoid of matter. Or at least I couldn't find any estimates as to how dense the solar system is there. But what about when they where still in the Kuiper belt? If Wikipedia is to be believed, ...


16

When Voyager was a shiny new probe just heading out back in 1977 (or Pioneer, Apollo, or really anything else we've sent beyond low earth orbit) it didn't have the ability to avoid hazards. It's trajectory was more-or-less fixed the moment the Titan booster cut it loose. The fuel it carried was for course corrections - gentle nudges to go past Jupiter at ...


13

Let me tell you how a typical satellite avoids debris, which I believe will answer your question about how Soyuz does it. All space objects are tracked by a US military organization called JSPOC. They also release data to those operating satellites via https://www.space-track.org/ . Note that they will not release information about US classified payloads ...


12

75 meters isn't all that rare - for the full public catalog there are 75 meter predictions about 2-3 times per day. What you have to consider is the uncertainty in that number. For TLE data, that's 75 meters +- several kilometers. The 75 meter miss distance is from the nominal position of each object at closest approach. But TLE data has a significant ...


11

As far as I know, other than for the GEO ring satellites are not assigned slots prior to launch. In the United States various regulatory bodies approve the launch of Earth-orbiting satellites depending on their mission (e.g. the FCC approves frequencies and communications, NOAA approves Earth-imaging satellites, etc.). Part of this licensing process ...


10

The main people who oversee this (at least in the US) is the Joint Space Operations Center (JSpOC), From Wikipedia: The purpose of the JSpOC is to provide a focal point for the operational employment of worldwide joint space forces and enable the Commander of JFCC SPACE (CDR JFCC SPACE) to integrate space power into global military operations. The JSpOC ...


8

Douglas Adams summed it up perfectly "Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." So first up, orbit is quite large, any individual orbiting item is fairly small. (ISS is a singular counter example as probably ...


7

A few notes... The conjunction screening volume for ISS isn't a cube. It's a rectangular box which is longer in-track and smallest in the radial direction. It kind of sounds like you're suggesting this volume is so that the spacecraft has time to maneuver. This isn't the case - any maneuver to mitigate a predicted conjunction would have to occur long ...


6

My initial thought was that, for a small number of orbiting craft, the orbits could be selected so as to not ever intersect, but some quick checking doesn't make it obvious that this is possible, since many of the orbiters have very eccentric, highly inclined orbits. MRO, 93° inclination, 250km-316km altitude MEx, 86.3°, 298km-10107km MAVEN, 75°, 150km-...


6

The probability of Voyager colliding with any matter any time soon is unknown, but likely small. We have no way of detecting small outer solar system objects, because they are small and far away. Therefore, we don't know how many of those bodies there are, and thus we cannot begin to estimate the probability quantitatively. But, space is big, so in all ...


6

The terrain around the rover is scanned with two sets of cameras: the navigation cameras and the hazard avoidance cameras. These cameras are installed in pairs: each pair generates stereoscopic images, so the rover can measure distances to and dimensions of obstacles. The images from these cameras is converted to a 3D map of the surrounding terrain. An ...


6

No, you can't fly through the rings you can see without hitting lots and lots of dust-sized ice particles at high velocity. Your vehicle will not fare well. The ring material is not sparse in that sense. There is a wide distribution of particle sizes from boulders to dust. There's a lot more dust-sized, so that's what you need to worry about. (I wouldn'...


6

Others have already clarified that the chance of encountering another massive body in interstellar space is astronomically small. However, there is still something to consider for course corrections, which is that a very small error in velocity early in your transfer orbit to Alpha Centauri can result in a huge error in your intercept with the system. ...


6

First of all, it was a miss. Whew! The close approach predicted at 21:53:00 UTC on 7 Jan 2017 has passed without incident. The JSpOC has confirmed that both satellites are being tracked as single objects, indicating that no collision has occurred. A few tidbits that might help narrow it down: The percentage is very high, which means the objects must be ...


6

This new, and aptly-named ArXiv preprint might help: The random walk of cars and their collision probabilities with planets. They iterated 48 estimates of Roadster's orbit, each for over 1000 years. It's conclusion (my emphasis): Its first close encounter that MAY come within a lunar distance of the Earth will occur in 2091. On timescales ...


5

No. Charging of objects in low earth orbit is already a major design issue but it does nothing to prevent collisions. The relative velocities are too high for achievable charges to matter.


5

The actual speed of impacts can be up to 14 km/s, it is something quite serious, even for small issues. There are a number of procedures taken to prevent such thing. The first level is known as the "Big Space" theorem, which is that space is really big, and there isn't that many objects. We are getting to the point where this isn't good enough overall. ...


5

The polar region is congested, but there are a couple of mitigating factors that make it not as bad as it may initially appear to be: Altitude separation The periods of polar orbits at similar altitudes are similar, so the timing of conjunctions varies slowly, facilitating their prediction. No special slot assignments are made, and conjunctions are dealt ...


5

Its not that obvious that placing an object in a retrograde orbit would quickly produce a Kessler syndrome. It may happen in the long run, but could take a while: I don't think the first collision is so inevitable. At GEO the chance of a collision is much lower than LEO and the debris threat in GEO presently comes less from large tracked objects as these ...


4

I dispute the premise of the question. Two satellites pose a danger of mutual collision if they are in orbit at the same altitude, but in different orbital planes. In this case, they could possibly collide at the two points where the line of intersection of the two planes crosses the orbit. Those two points exist for any pair of satellites. The point on ...


4

Given the signal lag, is there any active collision avoidance system aboard any of these craft? No. For that matter, such an active collision avoidance system does not exist for the International Space Station, either. The Space Station moves when told to do so by the ground. The Space Station has no capability of detecting when a collision is imminent. ...


4

The effects of gravity falls off very quickly (following the inverse square law) at large distances, so the pull of other stars would be negligible on the probe. This is even more so for planets in other systems, or comets/asteroids. As they are so far away, stars and planets would not be an issue. Encountering an ejected planet, asteroid, comet, etc. ...


Only top voted, non community-wiki answers of a minimum length are eligible