@Martin: Earth space debris navigation and future versions of Orbiter

[ar81]

If Orbiter is to simulate real space flight, it may simulate not only low thrust navigation (which is likely to be near future technology) but also space debris navigation (not like a Star Wars asteroid field) around Earth.

Nowadays space navigation is quite a challenge with all those objects in orbit. Inside Cheyenne mountains there is a center that gather data on space and aerial objects. There is the Space Control Center (SCC) that tracks all objects. In time fragments have their orbits being disturbed and they end up extending all around the globe.

Debris are produced by:

• Malfunctioning sats or sats that ended their useful life. There are more than 2000. They may remain in orbit for at least 10,000 years.
• Objects that are in orbit when putting sats in orbit. They include upper rocket stages, fairings, covers of certain optical systems, screws, attachments, cables that are used to attach parts, small particles of solid rockets.
• Fragments of accidental explosions. The first exploding rocket was used to launch US sat Transit 4-A in 1961. The explosion at 900km produced 294 detectable objects. Sometimes it happens after some time, like it happened to Arianne I in 1986 that exploded and produced 465 fragments. They explode necause of remnants of fuel, corrosion, or thermal fatigue, or other causes that cause leaks and mixture. Some sats may also explode, but this is a less frequent problem, caused by nickel-hydrogen batteries.
• Intentional explosion of satellites (caused by antisat satellites). For example Cosmos 249 produced 109 detectable objects. Also, some damaged or malfunctioning military satellites which atmospheric entry could not be controlled and that had secret equipment were destroyed so they could not bein the hands of enemies.
• Fragments caused by colisions. Each one may produce thousands of undetectable particles that may remain in space for thousands of years.

The real numbers are mostly unknown. Only the biggest objects are tracked.

The most efficient radars may detect objects of 10cm until 2000km. From 5000km optical systems are better. But how detectable an object might be depends on the distance. For geostationary orbit it is hard to detect objects smaller than 1 meter.

The most polluted orbits range from 800 to 1000 km ASL and also around 1500 km. In terms of mass they account for 99% of the mass. However a small particle could work as a very dangerous bullet at hypersonic speed.

They move between 28,000 km/hr and 40,000 km/hr. Space Shuttle windows have been hit by such particles, producing small craters. A 1 mm particle could kill an astronaut. This is why during EVA the bottom of the ship faces prograde and the nose points towards Earth to offer the best protection.

• In 1981 at 97 km ASL, Cosmos 1275 satellite was hit by debris and 306 fragments were produced.
• In 1996 french sat CERISE in polar orbit colided with fragments of an Arianne rocket at a relative sped of 50.000km/hr. It destroyed a satellite mast that was 6 meters long and it was cut in 2.
• In 1992 Cosmos 1508 passes 300 meters away from MIR space station.
• In 1999 an object passed 7 km away from ISS. In 2000 an object passed 2 km away from the station, according to SCC. If hab modules or duel tanks are hit, gyros, there might be critical damage.

Some sats are using screens of Kevlar and Nextel for objects smaller than 1 cm. For objects bigger than 1 cm there is no possible protection. Objects between 1 cm to 10 cm are the most dangerous for there is no suitable protection. Bigger objects are detectable and are tracked.

Travelling at 10 km/s it would be equivalent to an explosion of 12 times its mass in TNT.

Orbiter does not simulate debris cleaning operations yet. But it may at least simulate space debris field navigation in future versions.

This is just a suggestion for Martin, not a planned feature.

But it also should open the debate about the importance of space debris for space operations in the near future here in this forum.

 

[MeDiCS]

Why Martin? I'm sure he's busy fixing and enhancing the Orbiter core, and an addon implementing this should be fairly trivial and not everyone who downloads Orbiter may be interested on it.

 

[to be]

Why Martin? I'm sure he's busy fixing and enhancing the Orbiter core, and an addon implementing this should be fairly trivial and not everyone who downloads Orbiter may be interested on it.

I don't see how this could possibly be modeled in the current version of orbiter (it is certainly not "fairly trivial"), and even an update to orbiter would be very difficult. The only option I see is to model it as a percentage chance of collision, which I don't think would be terribly interesting to simulate.

 

[MeDiCS]

I don't see how this could possibly be modeled in the current version of orbiter (it is certainly not "fairly trivial"), and even an update to orbiter would be very difficult. The only option I see is to model it as a percentage chance of collision, which I don't think would be terribly interesting to simulate.

[ame="http://www.orbithangar.com/searchid.php?ID=3338"]Orbital Scenery v. 0.1[/ame]

Collision is another story altogether, but a debris field is easy to implement. Why do you say it's hard to do?

 

[N_Molson]

Very interesting. The first step would be a collision detection (even crude) between vessels. That is possible with the current SDK. (What we need is to detect if any vessel gets closer from a X distance from any other vessel (excepting the vessel itself of course), and then delete the 2 vessels).

Simulating a debris field would be very interesting. Some "random" debris field generation could do the work, provided you can set the altitude, the inclination, the density, the thickness... But new functions in the SDK would be necessary for that, I think.

That would be interesting because it would make some orbits "dangerous" and others "safe", and remind to the player that LEO is far from being a cold "void". And also that orbiting debris are an environnemental threat (and that space is an environnement).

The problem is that in real life, they know before the launch which are the orbits from most objects bigger than 10 centimeters. Which seems very difficult to simulate.

Edit : I wasn't aware of Orbital Scenery. Very nice work, as usual ! :thumbup:

 

[ar81]

You may need to simulate tether and its physics.
Debris fields using spacecrafts would clutter the vessel list in Orbiter, making the list not manageable.
Also the realism of sensors should be implemented.
I see all these factors being part of the Orbiter core.

 

[MeDiCS]

You may need to simulate tether and its physics.

[ame="http://www.orbithangar.com/searchid.php?ID=3399"]Ananke Tether-Sling v0.2[/ame]

[ame="http://www.orbithangar.com/searchid.php?ID=439"]TetherMFD 0.96 release[/ame]

Debris fields using spacecrafts would clutter the vessel list in Orbiter, making the list not manageable.

The same way SRBs would clutter the vessel list, but they don't. VESSEL::SetEnableFocus() should take care of that.

Also the realism of sensors should be implemented.

How so?

I see all these factors being part of the Orbiter core.

No.

 

[ar81]

Ananke Tether-Sling v0.2

TetherMFD 0.96 release

They never worked for me in Orbiter 2006. Why should they in 2010?

 

[RisingFury]

You know... I was wondering when the next "Martin!!! New Orbiter release, please!!!" thread would pop up...

ar81, what you're suggesting can be done independently of Orbiter. I think Artlav or someone actually did something like that a while back...

As for sensors and "incomplete" and "inaccurate" data, that would probably require being coded into individual vessels themselves. The problem with pushing that right into core is that you'll kill pretty much all vessel addons...

 

[n122vu]

Potentially, a module such as Orbital Scenery could process the Google Earth satellite database file, here, maybe a few generic meshes could be made initially and populated into the sim...

 

[statickid]

Orbital Scenery v. 0.1

Collision is another story altogether, but a debris field is easy to implement. Why do you say it's hard to do?

:OMG: can you imagine the differences in the space program with that much debris around the earth?????

 

[garyw]

This could be a better option -> [ame="http://www.orbithangar.com/searchid.php?ID=3868"]Heavens traffic 090405[/ame]

It certainly will help for existing, tracked satellites. No idea about space debris though.

Personally, I don't want any of that stuff in the orbiter core. I want Physics in the orbiter core, not the mess around the Earth. If I want a mess around the Earth then I can create it myself or get an addon to do it for me.

The beauty of Orbiter AS IT IS comes from the fact that it does the physics and presents some lovely eye candy. It doesn't limit itself to a point in time, I can fly Sputnik in 1957 if I want or I can fly World of 2001 if I want.

What you are proposing AR81, would limit the ability of people imagine because it would lock them in the here and now and that would be a terrible mistake.

If you really want to see orbital debris I'd have to suggest Celestia or similar with the necessary TLE's but leave the rest of us to our beautifully uncluttered solar system.

Now, where did I leave that probe? :lol:

 

[N_Molson]

What you are proposing AR81, would limit the ability of people imagine because it would lock them in the here and now and that would be a terrible mistake.

Yeah, that's really a good point. Orbiter core as it is allows almost any add-ons. We have to be smart & creative by using the SDK functions to reach our goals. Also, too advanced functions related to visuals (debris field) would prevent from running Orbiter on "lesser-performance" systems, which would be a disaster : it would'nt be really free anymore (you would need to buy a new computer to play it).

As an exemple, I would never had thought that the whole DanSteph's UmmU concept was even possible. So imagination and creativity are essential.

I've been playing with Orbiter these 10 last years, and only understood how to write C++ .dll modules this last year. But I knew nothing about that. I think it's important that more and more people get into this. There are excellent tutorials around (thanks ComputerRex), and the SDK documentation is really complete (I'd like to have a "real" exemple for each function in it, but tutorials do the job).

Still, I agree with what ar81 said about space debris. But yeah, this can be done with the SDK, it's more a matter of skill (and time, especially if you need to refer the SDK doc for each line you write like me)

To sum up, maybe Orbiter's spirit is "I'd like to see this feature in Orbiter, that would be cool, but I did'nt found any addons on that, so let's do it my own way !"

 

[Enjo]

Edit : I wasn't aware of Orbital Scenery. Very nice work, as usual ! :thumbup:

Thank you However note that it's just a toy, which uses cruel simplifications. For example the debris are shown only to your camera to cut on CPU usage which is BTW a problem that you noticed yourself.