portillo

Exactly, that is the real problem, the lack of competition from terrestrial networks. In the US the ISPs operate as a monopoly. In most big cities in Europe you have 3/4 providers to choose from, which reduces costs and increases the quality of service.

I am not talking fiber to the home, I am talking a fiber backed infrastructure, like cell towers and such.

If the solution was to provide Internet wirelessly, we would have that right now. The cell phone infrastructure provides much higher data-densities than any satellite network will ever be able to provide.

I don't think that latency is a decisive factor for most people / networks (as long as its below certain threshold). Most people will tell you it's a price-based decision.

On the other hand, roughly 85% of the population worldwide is already covered by 3G or 4G networks. I am not sure that space will be able to offer lower prices for backhaul if the infrastructure is already there. A fiber PoP / tower has much lower OPEX than launching, operating a constellation of satellites.

Good luck making a business case with ARPUs of 3-4 USD / month from those people.

They have nothing to do in big cities, they cannot deliver the required data-rate density (bps/km2).

This is complete nonsense. There is not enough demand for all those satellites and capacity, so it's very hard to understand why they are making such a filing.

As of today, there is probably ~ 1 Tbps of usable capacity in space (wordlwide). With such a big constellation they could provide 100x this capacity, but who is going to buy it? How are they going to compete with fiber-delivered Internet in big cities? They cannot offer the same QoS, so you do not want space delivered Internet if you can have it through terrestrial networks.

If all the constellation + GEO systems proposals end up being launched, there will be an oversupply of capacity from space.

Rural areas are a viable market only in the US and Canada, where people can afford to pay $50+/month for connectivity. Elsewhere in the world, they are not going to sell to any end-users.

The 4,425 and the 7,500 satellite constellations proposed by SpaceX are way oversized and simply put, a waste of money and efforts.

1.- As an individual, the cheapest and simplest options would be to use Nanoracks, Spaceflight, or a similar company that handles most of the launch process. Their price is ~$100k for a 1U Cubesat. I have serious doubts that they would be OK with a 3x3x3 cm satellite, as these are really hard to track and they are big enough that, if there is a collision, they can cause some serious damage. See for example https://spacenews.com/fcc-fines-swarm-900000-for-unauthorize...

2.- Yes, there are. For example, in terms of materials, you can check http://nanoracks.com/wp-content/uploads/standard-materials-a.... Yes, in satellites there are several things that normally unfold (i.e., solar panels, antennas, sensors)

3.- They normally undergo (at least) outgassing, vacuum, vibration, and thermal testing. Not sure if all of them are mandatory. I would say that outgassing is a must in most places. See http://nanoracks.com/wp-content/uploads/flammability-offgass...

4.- Yes, some people have launched things much much smaller than a Cubesat (like Chipsat), but normally you would be required to decay/deorbit quite quickly since as I mentioned, space people don't like small things flying around.

5.- If you use a launch provider, you normally do integration at their facilities. Then they handle the rest of the process for you. I would say that a normal deadline for integration is ~3 months before launch?

Yes, it is all solar power.

5.5 kW is not a lot of power, modern buses for geostationary satellites (i.e., 720HP) can produce close to ~18 kW, of which ~80-90 % are normally used by the payload in a communications satellite.

I agree with you. I should have said that I think they were not looking to maximize the system throughput when designing the system, instead wanted to test this new technology. Seems the 450 kg Quantum payload has a 5.5 kW power consumption, so yeah, that phased array seems to be drawing quite a lot of power.

I am curious about your thoughts on future satellite architectures since it looks like some players are betting in full flexibility by means of DRA / phased-arrays technology (SES, SpaceX, Telesat), whereas others (Viasat) seems to be betting on fixed-spot beams + flexibility in spectrum, bandwidth, and power allocations.

Seems that those 8 beams can be further subdivided in different spot beams (not sure how many subdivisions are possible though). Also, a previous article [1] mentions that they are actually limited to a maximum of 1 GHz/beam (I understand each of the 8 beams is limited to 1 GHz).

My impression is that this is more of a tech demonstration satellite (to test the new payload, resource management software, etc) rather than an actual commercial satellite, as the total throughput seems to be much lower than state-of-the-art spacecraft from other companies.

[1] https://spacenews.com/eutelsat-adding-two-more-quantum-satel...

Initially, in 2015, they were talking about ~6-7 Gbps [1] but my guess is that the current design allows for a little bit more of throughput (8 beams @ 1 GHz/beam (max. BW) x 2 bps/Hz (?) -> 16 Gbps (?)). In any case, I would say this is a technology demonstrator satellite.

I think that their main innovation might be the software to optimally allocate power, bandwidth, spectrum, and pointing and shape of each beam so that throughput/revenue /"quality of service" is maximized, which might be run on the ground and then the "instructions" sent over the TT&C link to the satellite. I doubt that the spacecraft has the autonomy level required to conduct all these tasks onboard.

[1] https://spacenews.com/eutelsat-esa-taking-a-quantum-leap-tow...

That headline is quite misleading, as there are several re-configurable "software-defined" satellites active in orbit, each one presenting different degrees of flexibility. Dynamic power and frequency allocation have been used since the first HTS (Viasat-1, Echostar 23...), while dynamic bandwidth allocation is also a standard design in new satellites (Viasat-2, for example).

Furthermore, other satellites such as Hispasat 36W-1 already have direct radiating arrays / phase-arrays (which I am pretty sure is the core technology of EUTELSAT's Quantum). Sure, Quantum might be (one of) the first satellite that makes full use of this technology, but this is the current trend and all the big satellite comms. companies are going to launch a similar satellite in the next 1-2 years (SES-17, SpaceX Starlink, mPower...).

In any case, I believe that the dynamic resource management (DRM) software (which EUTELSAT claims to have developed) will play a crucial role in all these new satellites. Given the payload flexibility, optimally configuring all these degrees of freedom will become a very very challenging task.