[Sally Le Page (OP)]

We've this question in from listener Matt:

"With three space missions currently converging on Mars how do the nations avoid orbital collisions? Do they share data, do they have transponders or space traffic control etc?"

What do you think?

[Origin]

Off the top of my head I would say, no, there is little or no coordination.  The chances of a collision is so remote as to be essentially impossible.  We are talking about 3 tiny objects orbiting an entire planet. 

[Bored chemist]

Off the top of my head I would say, no, there is little or no coordination.  The chances of a collision is so remote as to be essentially impossible.  We are talking about 3 tiny objects orbiting an entire planet. 

That's fine... until they decide to put them in circumpolar orbits synchronised to be above the bit of the ground where it's local noon or some such, but one of them chooses to orbit their craft in the opposite direction

[Zer0]

Hello Matt & thank you for your Question.

https://en.m.wikipedia.org/wiki/Space_traffic_management#:~:text=Space%20traffic%20management%20is%20defined,or%20radio%2Dfrequency%20interference.%22

Ps - The link is for a Wikipedia Article which explains the Subject in brief, hope it shall be helpful.
👍
(Do " Listeners " just have singled out questions? Once it is answered, do they then Not have follow-up Queries? Why do " Guests " shy away from registering?)

[evan_au]

There is a US-based program to scan Earth orbit for orbiting debris - one of the ground sites is at Australia's Mount Stromlo. This program issues warnings when debris is on a collision course with active satellites, so they can take evasive action. The ISS often has to make emergency orbit height increases.

I am sure that other countries have their own similar programs. At the moment, we really can't do anything about removing orbital debris, so these programs are reactive.

There are also rules about de-orbiting defunct satellites in low-earth orbit when they reach end of life, and putting defunct geosynchronous satellites into a graveyard orbit. But these will not help older satellites or malfunctioning satellites.

[alancalverd]

There has been at least one successful mission to destroy a dead satellite, but at orbital speeds I guess that microscopic shrapnel can be as worrying as a single big lump that you can see on radar.

[Origin]

That's fine... until they decide to put them in circumpolar orbits synchronised to be above the bit of the ground where it's local noon or some such, but one of them chooses to orbit their craft in the opposite direction

Seems to me the chances of a collision is still essentially zero.  I will research it, I could be wrong of course.

[fenix21]

Hello, I think that they do not communicate, rather, for sure, there is almost no chance of a collision, these are large plantets, for sure larger than the ground, so there is no chance of a collision even without communication

[Zer0]

Apologies for just posting a link & petering out.
🙏
(Certainly not the tradition for TNS)

There are Organisations set up at National as well as International level.

Global cooperation is a must for it to work.

United Nations has a specific bureau, UNOOSA.
(United Nations Office for Outer Space Affairs)

One can also simply read up about the IAA & STM...in details thru the Wikipedia link provided above.
(International Academy of Astronautics)
(Space Traffic Management)

Ps - Interesting to know Nobody can own the Moon, still folks claim to have bought lunar property online & also have valid certificates as proof of purchase.
🌚

[Zer0]

There has been at least one successful mission to destroy a dead satellite, but at orbital speeds I guess that microscopic shrapnel can be as worrying as a single big lump that you can see on radar.

Hi Sally...Hey Matt!

I should have taken Note of this before.
Don't know how i missed out on this Hint.
My Bad!

" The US has condemned Russia for conducting a "dangerous and irresponsible" missile test that it says endangered the crew aboard the International Space Station (ISS). "

Source - https://www.bbc.com/news/science-environment-59299101

Ps - I'm getting a bit tired lately of making contradictory statements.
Not that I'm doing it purposely, but it somehow feels like The Whole Universe has conspired against Mee & is now out to get me.

UNOOSA...STM...IAA...Futile!
This World only looks orderly from the outside, but inside it's really quite chaotic.

EDIT - To be Fair, Even India & China have conducted similar tests in the past, which have been deemed Irresponsibly Negligent Behaviour.
America has also conducted testing, but with Caution.

[Sally Le Page (OP)]

We answered this question on this week's show. You can have a listen here:

https://www.thenakedscientists.com/podcasts/question-week/how-do-we-prevent-space-collisions [nofollow]

[evan_au]

Could the Russian missile test really have been aimed at the Elon Musk's Starlink satellite constellation?
- The target spy satellite was reportedly at an altitude of around 480km
- Starlink has a thousand satellites in orbits around 550km altitude, with more planned for 540km

Could the cloud of debris intersect the Starlink orbital planes, and gradually trash them?
Could this end Elon's plans for global telecommunications domination?
https://en.wikipedia.org/wiki/Starlink#Constellation_design_and_status

[Ken Raisen]

Traffic control is nearly impossible in my opinion. When you try to control the objects in space to maintain it in an orderly manner so that it can prevent collision in space, it need more energy than ever.

It is true that many collision incidents may occur. Recently we heard that Russian space debris came in near collision with a working Chinese satellite.

But to implement space traffic control, and to maintain safety -> coordination among countries, excess use of energy and regulating the present satellites have to takes place, which makes it a definitely impossible thing to occur.

[evan_au]

Russian space debris came in near collision with a working Chinese satellite

I didn't hear about that incident...
- But I did hear about the Russians conducting an anti-satellite test where debris came near the manned ISS (ironically, some of the astronauts on the ISS are always Russian).
- And I did hear the Chinese complain that Starlink satellites came near the Chinese Tiangong manned space laboratory.

to implement space traffic control... excess use of energy

It takes an enormous amount of energy to place a payload into orbit.
International coordination takes a lot less energy than continually replacing satellites that get hit by space junk.

There is a real risk that some orbits will become unusable, as space junk will crash into satellites, producing more space junk...the Kessler syndrome.
https://en.wikipedia.org/wiki/Kessler_syndrome