Comment by gravypod | Hacker News Reader

Comment by gravypod | Hacker News Reader

I'm pretty sure you don't need to de-orbit CubeSats manually. The drag on the satellite will slowly decay the orbit of CubeSats much faster then most satellites.

We also already use "de-orbiting" systems in real satellites: we just burn their remaining fuel in the RCSs to either push them back into space (the normally talked about junk cloud) or we pull them into a decaying orbit (what already happens with CubeSats). The only reason this is done in the big-leagues is because the average "normal" satellite is about the size of a small car.

A CubeSat will effectively be taken out by gravity/drift very quickly (most missions are 2 months to 2 years) and it is perfectly safe to do so.

I don't see how this is a "Space Junk Solution" and from the article:

> "The planned demonstration is an important milestone to develop and promote the use of this technology," Krag told Space.com. [Space Junk Explained: How Orbital Debris Threatens Future of Spaceflight (Infographic)]

1. This is already something we do

2. This is no needed in CubeSats

> That's where D3 comes in. The device has independent power supply and communication systems. That means that D3 can deorbit a satellite even if the rest of the spacecraft is completely unresponsive, D-Orbit representatives said.

Totally independent system to provide redundancy for de-orbit in case control to the main satellite is lost, which is a problem.

Yes, and D3 it's also an active removal sistem, that means that you can deorbit the satellite in pre selected locations and moment (like an ocean) in a matter of minutes, being in control of it. This does not happen when using tether or solar sail for deorbiting purpose and it may take years, depending on the orbit. Its basically the difference between parking a car and jumping out of it waiting for drag and friction to stop it.

See SES's geo bird, which seems to have slightly blown up over the weekend.

removing satellites from orbit quickly will be needed when constellation programs will start. Guys like Eelon Musk plans to launch thousends of cubesats and deorbiting norms and techniques will be needed and probably mandatory. Launching a cubesat costs a fraction compared to launching a 1 ton satellite, so you can end up launching 50 satellites instead of 1 and make them work tigether.

today we count something close to 1700 active satelite and dubling this number in a year (and maybe again the year after) it is a step that have to be done right, the first time because space is big but the good orbits are few; and a kessler syndrome scenario is possible. It is imaginable that to keep the whole carousel running, you need to be able to launch and dispose satellites quickly and safely.

And even though tethers are not exactly the quicker or safer system, there is a lot of work to be done and is interesting that PSLV C-38 launched many deorbiting devices.

I don't think the point is to deorbit cubesats, it's as an independent module to deorbit larger satellites.

It's not for cubesats, it's just the easiest way to test it.

Also, many satellites are not deorbited. Most satellites in medium to high orbits, especially those in geostationary orbit, are moved into graveyard orbits near their end of life when they are still operational, but they lack sufficient propulsion to deorbit or bring their perigees low enough for their orbits to degrade in a meaningful amount of time.

The point of this experiment is to test out a device that doesn't add significant extra mass to a satellite but would be able to deorbit it in a timely manner after it has reached the end of its usefulness. This would be a big step in keeping Earth orbit clean from space junk and is a worthy research endeavor, especially considering the low costs involved.

People want to send CubeSats higher than LEO, and, this is a prototype of something they want to build much larger versions of. Do you know if any existing satellites have a dedicated power and communications system for just deorbiting? Something that doesn't necessarily fail if the rest of the satellite has a problem.

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