Post by: Just thinking on 11/07/2021 12:12:55
Post by: evan_au on 12/07/2021 11:00:52
- This means that many large pieces of de-orbited space junk will come down in the South Pacific (between New Zealand and Chile), where there is almost no-one to see them
- For boosters, they often come down in a known zone down-range of the launch pad. All shipping and airlines are warned to stay clear of the landing zone. (The extreme case is the reusable boosters, where they return to launch site, or to a barge in the open ocean...)
- Most meteors come in known meteor showers (debris from Near Earth comets), which can be predicted well in advance, and have a known source, or "radiant".
It is the sporadic meteors and the uncontrolled space junk that causes surprises.
- Fortunately, telescopes are getting better at detecting large rocks as they are approaching Earth (although often by just a day).
- That should improve dramatically when the Vera Rubin Observatory comes online around 2023. See: https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory
Here is the final path of a Chinese Long March rocket that did not have a workable reentry plan. Observers knew with reasonable accuracy the ground track of the booster, but they couldn't tell where it would land along that ground track.
Chinese_Long_March_Booster_Reentry_May-21.jpg (68.12 kB . 970x486 - viewed 5926 times)
Post by: Just thinking on 12/07/2021 11:18:26
It is the sporadic meteors and the uncontrolled space junk that causes surprises.You make a number of very good points I should have mentioned that space junk is by far more rarer than meteorites.
Post by: Europa on 25/07/2021 01:59:27
Current space launches are supposed to have plans for safe re-entry of the vehicle at end of life, so they don't contribute to a cascade of space junk (as portrayed in the movie Gravity).What would the plans be for a satellite without thrusters be for reentry after a decades long life? Even if the satellite is new
- This means that many large pieces of de-orbited space junk will come down in the South Pacific (between New Zealand and Chile), where there is almost no-one to see them
- For boosters, they often come down in a known zone down-range of the launch pad. All shipping and airlines are warned to stay clear of the landing zone. (The extreme case is the reusable boosters, where they return to launch site, or to a barge in the open ocean...)
- Most meteors come in known meteor showers (debris from Near Earth comets), which can be predicted well in advance, and have a known source, or "radiant".
It is the sporadic meteors and the uncontrolled space junk that causes surprises.
- Fortunately, telescopes are getting better at detecting large rocks as they are approaching Earth (although often by just a day).
- That should improve dramatically when the Vera Rubin Observatory comes online around 2023. See: https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory
Here is the final path of a Chinese Long March rocket that did not have a workable reentry plan. Observers knew with reasonable accuracy the ground track of the booster, but they couldn't tell where it would land along that ground track.
Post by: Bored chemist on 25/07/2021 11:39:17
What would the plans be for a satellite without thrusters be for reentry after a decades long life?There would not be one.
And we know that
Current space launches are supposed to have plans for safe re-entry of the vehicle at end of lifeSo we deduce that satellites are supposed to have thrusters at the ends of their lives.
Do you find the inability to combine pieces of information and make deductions is a problem for you in your everyday life?
Post by: Petrochemicals on 26/07/2021 00:41:08
Post by: Just thinking on 26/07/2021 09:17:01
X rays. Get yourself an xray gun and have a look being as metal will reflect the xray much better.And a speed gun see how fast it's going.
Post by: evan_au on 26/07/2021 10:18:26
Quote from: bored chemist
So we deduce that satellites are supposed to have thrusters at the ends of their lives.Not necessarily. If the satellite is in a low orbit, it will naturally deorbit due to friction with the upper atmosphere.
- Guidelines recommend that satellites should be removed from orbit within 25 years of their end-of-life
- This is especially useful for cubesats. They have very little space for electronics, let alone thrusters.
- But depending on atmospheric friction can be unpredictable - an outburst from the Sun can suddenly expand the outer atmosphere, and result in premature termination of the satellite mission.
See: https://en.wikipedia.org/wiki/Space_debris#Dealing_with_debris
Post by: Just thinking on 26/07/2021 10:38:10
Not necessarily. If the satellite is in a low orbit, it will naturally deorbit due to friction with the upper atmosphere.I believe that satellites are designed to fragment to allow for a compleat burnup most probably the larger ones.
- Guidelines recommend that satellites should be removed from orbit within 25 years of their end-of-life
- This is especially useful for cubesats. They have very little space for electronics, let alone thrusters.
- But depending on atmospheric friction can be unpredictable - an outburst from the Sun can suddenly expand the outer atmosphere, and result in premature termination of the satellite mission.
Post by: Bored chemist on 26/07/2021 11:07:44
X rays. Get yourself an xray gun and have a look being as metal will reflect the xray much better.You seem to have picked the wrong wavelengths.
Metals are shiny.
They typically reflect light well.
And they are conductive, so they typically reflect radio waves well.
But they aren't particularly opaque to. or reflective of, X-rays.
If they were then we could make X-ray telescopes using ordinary mirrors (rather than grazing angle ones).
True; but I'm not sure how it applies to a satellite with a "decades long life".Quote from: bored chemistSo we deduce that satellites are supposed to have thrusters at the ends of their lives.Not necessarily. If the satellite is in a low orbit, it will naturally deorbit due to friction with the upper atmosphere.
- Guidelines recommend that satellites should be removed from orbit within 25 years of their end-of-life
- This is especially useful for cubesats. They have very little space for electronics, let alone thrusters.
- But depending on atmospheric friction can be unpredictable - an outburst from the Sun can suddenly expand the outer atmosphere, and result in premature termination of the satellite mission.
See: https://en.wikipedia.org/wiki/Space_debris#Dealing_with_debris
Post by: Bored chemist on 26/07/2021 19:51:35
I am guessingYou should stop; your guesses are so silly that you are embarrassing yourself.
What scale was your 173 IQ achieved on?
My guess is the Stanford–Binet scale
2nd or 3rd edition.
Post by: TommyJ on 27/07/2021 15:30:01
Occurrences like large asteroids are rare, but natural activities, such as solar storms, strike from space much more frequently. These have a direct effect on electronic systems, especially satellite-based technologies.
The burst of human-made satellites has created a space hazard of its own, as the loads of orbiting debris have the potential to destroy other satellites.
In the US both NASA and the U.S. Space Force tracks space debris, the National Oceanic and Atmospheric Administration monitor space weather, Planetary Defense Coordination Office coordinates the search for potentially hazardous asteroids and other near-Earth objects (NEOs).
The European Space Agency (ESA) has pulled all these activities together under the umbrella of its Space Situational Awareness program.
The key should be in collecting all the data together and handling it with the help of Data Science methods.
Post by: Just thinking on 16/08/2021 12:46:32
The key should be in collecting all the data together and handling it with the help of Data Science methods.This is something to consider but not necessary for space junk and meteors.
Post by: TommyJ on 18/08/2021 12:43:10
2008 TC3 (ateroid though), exploding over Sudan.
https://en.wikipedia.org/wiki/2008_TC3
One of examples.
The asteroid was discovered by Richard A. Kowalski at the Catalina Sky Survey (CSS) 1.5-meter telescope at Mount Lemmon, north of Tucson, Arizona, US, on October 6, 06:39 UTC, 19 hours before the impact.
'as they burn crossing the sky' already might be a matter of a second to take note of time and place and try to find out later.
One of the largest junk piece is about double decker size. But the most dangerous on the orbit itself are ones from 1 to 10 cm, which can easily make working satellite into a junk waiting to make surprise in atmosphere.
Post by: Just thinking on 18/08/2021 18:41:36
One of the largest junk piece is about double decker size. But the most dangerous on the orbit itself are ones from 1 to 10 cm, which can easily make working satellite into a junk waiting to make surprise in atmosphere.That is of big concern if a satellite is impacted by either a small meteor or a piece of space junk it will become a runaway problem. I think this has happened before and we have so far avoided moor. Just wait till space X is complete it could become a train reck.
Post by: TommyJ on 19/08/2021 08:10:28
And one bright satellite collision that was in the news before.
For new launches, yes, avoided so far, but for what is there only owners might know.
Post by: Just thinking on 19/08/2021 10:50:53
ISS had to take several manoeuvres last year.They must have to have plenty of notice if an object is on a posable collision course with ISS as ISS is very large and will take a bit of time to reposition.
Post by: TommyJ on 19/08/2021 10:57:13
Yes, and it is man driven and precisely observed.ISS had to take several manoeuvres last year.They must have to have plenty of notice if an object is on a posable collision course with ISS as ISS is very large and will take a bit of time to reposition.
Other 20k+ are either junk or not so sophisticated in this way, what I meant.
Post by: Just thinking on 19/08/2021 11:31:10
Yes, and it is man driven and precisely observed.I guess ISS is rather special as it is occupied and any collision will be of the greatest concern And ISS is one of the earth's greatest allies builder in space.
Other 20k+ are either junk or not so sophisticated in this way, what I meant.
Post by: TommyJ on 19/08/2021 12:02:31
Fully agree, no argue would be possible.Yes, and it is man driven and precisely observed.I guess ISS is rather special as it is occupied and any collision will be of the greatest concern And ISS is one of the earth's greatest allies builder in space.
Other 20k+ are either junk or not so sophisticated in this way, what I meant.
I think of statistically it is one of 20k+ objects (even the big one). So a math model would show thousands collisions times for the whole.
Post by: parker99 on 19/08/2021 12:49:43
Post by: Eternal Student on 19/08/2021 12:56:29
I'm guessing you're new here. Welcome. That looks like a perfectly sensible and good first post.
Yes, space junk is a great concern. Many of the earlier replies in this thread echo your opinion.
Best Wishes.
Post by: Just thinking on 19/08/2021 13:02:30
I think of statistically it is one of 20k+ objects (even the big one). So a math model would show thousands collisions times for the whole.Yes, it would be a total loss if too many collisions occur we will have to do a better job at hard wiring the world. I don't know why they haven't placed communication towers across the oceans. This won't cover all of the benefits that satellites bring.
Post by: parker99 on 20/08/2021 11:54:09
Hi @parker99.Thank you) I am happy to join this forum and discuss some science news. Also, I wanna add a few more words about space debris.There are some missions that will be launched soon in order to deal with the space debris issue.
I'm guessing you're new here. Welcome. That looks like a perfectly sensible and good first post.
Yes, space junk is a great concern. Many of the earlier replies in this thread echo your opinion.
Best Wishes.
Post by: TommyJ on 20/08/2021 12:08:26
Having 20k+ junk pieces already on the orbit for all the time, it looks inevitable as a result of Starlink, sending 15k and preparing twice more.
I assume, there must be mitigation points behind:
- Where the collision numbers become critical to hold on new launches.
- Automatic manoeuvring systems continuous calibration.
- Emergency actions for the critical collisions that might happen.
Still to have more experience of distinguishing between space junk and meteors, finding the best location for occurrences observation, may be advantageous.
Post by: Just thinking on 22/08/2021 17:56:36
Still to have more experience of distinguishing between space junk and meteors, finding the best location for occurrences observation, may be advantageous.I enjoy astrophotography and in a few years they say we won't be able to get a photo without a satellite being in it.
Post by: emelymorris on 26/08/2021 13:45:44
But as for the garbage, not everything is so good, because the problem is getting worse, it only gets bigger. The spammy.com briefed me on the current situation.
Now there are more than seven tons of debris in low-earth orbit, although this is not so significant for the scale of space, it already creates emergency situations for the MSC, satellites, and others. There are more and more ideas of technologies that are ready to work on solving this problem, such as a space vacuum cleaner, a laser, even AI.
Post by: Just thinking on 26/08/2021 14:15:34
Space debris is the work of man, it is important to understand that we have created this danger ourselves. This is probably the most significant difference between space debris and asteroids.Space junk is like sand yes very dangerous but asteroids are like a freight train very very dangerous. Space junk is more a kind to meteors the big difference between meteors and space junk is that space junk orbits and hangs around longer waiting for a victim. All are bad if they meet their target.