marsokod

Part of the discussion on the drag sails was that while they are decreasing the time in orbit, they are increasing the collision area and therefore the general risk of collision remains the same.

Tethers are somewhat better but hard to work with. Propulsion is the best bet at the moment.

One consequence of this ruling could also be in the orbit insertion strategy. Currently agencies are not too worried about your satellite being in working condition in orbit as long as you demonstrate the risk of collision is low enough through natural means. Now that we are likely required to use active deorbiting system (and possibly active collision avoidance), the rules may be more tightened regarding testing and analysis.

There is some confusion with different issues, you are right. There are several problems that create a perfect storm:

1. As you said, the water issue is just temporary. This is a non-issue for this winter. 2. The next generation NPP, the EPR, is late and is currently only planned for 2023 3. The current NPPs have been authorised to be used up to 50 years, under the condition of doing fairly important upgrades. This is what is ongoing. And because the decision to push these to 50 years was late, the upgrade schedule is quite tight. 4. This upgrade, and other normal maintenance have been impacted by COVID 5. As someone else said, corrosion was discovered during the maintenance of an NPP. Since the cause of the corrosion could not be explained, the operator decided to shut down all the NPPs with the same design. This is being currently analysed and it looks like the nuclear authority is happy with the proposal. The current work is to develop a reliable system to detect and monitor this corrosion, not a change in the design 6. The main operator is in the process of being fully nationalised and is suffering financially as it was basically asked to bail out its competitors this year due to the energy crisis. 7. The backup to NPPs in France is currently gas. And you may be aware of a small constraint on gas due to some issues with a country located further East. If Russia stops the delivery completely, gas supply could be an issue and therefore we need to plan to reopen coal plants that were closed because they were no longer useful.

> Its reactors are getting old enough that their capacity factors have declined - in 2020 down to 62%. This isnt much ahead of the capacity factor of the best wind turbines (57%).

The situation is a bit more nuanced than that. Yes the capacity factor has reduced but not only because they are getting old:

1. Wind and solar have priority access to the grid in France. If they are producing a lot, the NPPs have no choice but to cut their power output, reducing artificially their capacity factor. 2. The NPP reached their end of planned life, meaning they had to do an extensive refit to get a life extension. This is a bit more than just regular maintenance, these are upgrades to more current security standards. 3. As you said, the older the NPP become, the more maintenance is required

It can follow the fluctuations during the day. That's what is done in France. It is not efficient at all since a NPP cost mostly the same regardless of its power generation, and is technically a bit more complex, but perfectly doable.

The whole papers revolves around this claim:

> Marine plants like diatoms produce omega 3 oil which acts like a cap on the surface of the water to slow down evaporation

There are no numbers about this, no reference, nothing. And this claim is quite extraordinary. This absolutely needs to be quantified in order to go further. How does omega 3 oil, rejected by sea life on a limited portion of the sea, a product that can be oxidized easily, be a significant barrier to evaporation.

Maybe this is true, I don't know. But this is definitely counter intuitive and any counter intuitive claim should be supported by something, not just hand waived like that.

That's not really the intention behind the initial concept. If you are able to update a plane to make it more efficient while keeping the same behaviour and the same interfaces for the pilot, then it is great and there are no safety concerns with that.

The only issue on the Max is that as part of the refresh, they were not able to keep the same behaviour. And then, instead of fixing it with additional engineering or requiring new training, they hid that under the carpet and made sure the FAA accept itq, leading to crashes and deaths. Plus the denial after the first crash was really disgusting.

It depends on what you are talking about. If you are talking about a battery car, then it is better to use a number that makes sense for the end user, and number of charge cycle is not an easy one. If you recharge from 70% to 90% every day, is that a cycle, is that 1/5th of a cycle?

The main problem is the number of full capacity cycling a battery cell can do can change widely based in how it is used. So it depends on how it is integrated into a car and how the car is being used. A typical Li-Ion cell will last a few hundred cycles if cycled completely at a high rate without proper thermal control. But this number can easily be multiplied by 10 with proper thermal management, not charging it to max voltage and doing shallower cycling. If you want to give a number for a final product, you are bound to make assumptions on how it will be used. And at this point you just have an equivalence between distance driven and cycling count.

Also, age has less impact than cycling count in the context of a properly designed battery pack. The two main factors for battery degradation are time spent at high temperature and high state of charge, and cycling count (with speed and depth being the key elements). EV manufacturers are keeping a buffer for that purpose and their batteries do not spend a lot of time at high state of charge where the chemical degradation is more effective.

Not only that, but Volvo is procuring their batteries in China and the footprint for battery production is deeply impacted by the carbon intensity of the grid where it is produced. So using a Volvo is already close to a worst case for the battery production.

Any reduction in this can have a big effect. The EV here is 10.7tons more intensive to build, and the battery counts for 7 tons.

It is exactly the same. You have many modules for Home Assistant (through HACS, none is an official module yet) that will use a similar setup.

I use it mostly to track and keep a record of my Niro status.

The cost of nuclear energy is actually in the law since EDF has to sell some of its production at cost to other providers. The evaluation is done by the CRE.

It's not only a launcher issue (and given the timeline, switching launcher is unlikely feasible even if the rocket is available). The descent module is russian made (with ESA bits in it), so the rover is now stuck. This launch window is dead.

Stopping the partnership with Roscosmos means redeveloping a descent module and either collaborate with NASA/JPL or develop new technologies from scratch in Europe. Even 2 years is optimistic for this.

You've got loads of hydroelectricity in Québec, that's fairly cheap. In Europe most of the electricity was (and still is) generated with fossil fuel so if you are going to heat a place, you might as well use the gas directly, that's more efficient.

There are a few special cases though: if you go in southern Europe, especially in Greek islands, you will find a lot of solar water heating. And France has a higher than average electric heating due to its nuclear grid.

For LEO missions, the source is now typically a GNSS receiver outputting a PPS line. Otherwise, you try to have a precise clock (TCXO, OCXO, and now CSAC are available) as a reference distributing the time to all the subsystems, and you correct the satellite time offset from the ground (similar to NTP).

The EV6 and the Ioniq 5 are at the same level as the Model Y. They charge as fast, if not faster, are slightly cheaper (at least on the UK market) and have a better range.

I can think of the e-niro, but that's about it. Maybe the Peugeot e-208.

But yes, these are exceptions.

There are many simulations like that when sadistic engineers (sorry, simulation engineers) will inject errors in the simulator and see how the operators react. Then the operators have to find a way out. This is also used to make sure that monitorings and procedures cover all the errors.

Amperage is set by the resistance of the human body. That's in the order of 2kOhm, so at 50V, you get a current of 25mA. That's in the zone where it becomes quite intense for you.

At 12V, we are just talking about 6mA, where you can feel the electricity but it should not be hurting too much.

Yes, and the x2 figure is the usual estimation when checking this at a company level.

Have a look at how many http queries it is sending. It's like they are sending a unique query for every word used in each page. This is horrendous.

That's a bit of an exaggeration for sure. But dust can be an issue in connectors, making the connection not as stable as expected or even break the connection on a pin if there is enough.

There is also the risk of short circuit on non-coated PCB, increased ESD risk. And beyond PCB, there are a lot of other risks mitigated by clean room environments: dust on sensors, dust on bearings or gears, dust on optical cameras... And any deposit of dust will float around everywhere once in orbit, especially after being shaken and vented during launch.

Could you make a satellite in your garage without a clean room environment? Yes sure, and you would even have a decent chance to have a working satellite once in orbit if you know what you are doing. Would you accept a 50% failure rate if you are flying a payload worth a few millions and need to spend a similar amount on launch cost? Probably not.

They do, but for small scale projects like satellites we tend to push con-coat until we have a good confidence the unit is working. Removing conformal coating to replace a failed component or change a resistor can be quite tricky, especially for epoxy based coatings. So there is a long time without any coating (up to spacecraft assembly).

Here Facebook is not targeting anti-lockdown accounts here. It's just the shortcut used by the article's title but the targeting is different. They are targeting accounts that are coordinating themselves to spread misinformation and incite violence.

Do we actually have costs for the boreholes? Looking at the IDDP (geothermal deep borehole at 5km), I see costs of $22M. So we are talking about around $20B for the 800 boreholes forecasted for all the waste ever generated in the US. That sounds quite cheap to me.

My theory is more that they will add the functionality to Starlink. Worst case, you just plug the RF part of the swarm cubesat on the outside of a Starlink. This way Starlink immediately supports low power devices, has a ground segment for the end-users readily available, and solves the latency/backhaul problem that all these cubesat constellations have.

It was closer to $6B, still more than twice than SpaceX though.

Yes, but the problem with Li-Ion fire in a confined environment is that it generates a lot of toxic gas (doable but you need equipment for that), a lot of hydrogen which will react with everything near by, and the risk of explosion (in the sense of rapid fire expansion with a thermal run-away of most cells) is higher.

My guess is that the floor was poorly ventilated with complex access, rendering the access to the fire unnecessarily hazardous.

It is a fully automated vehicle. They have done a few flights and the capsule is actually landing with a parachute so they don't have to worry about the rocket landing being a failure.

Not anymore. Now it's almost everything is EAR, and ITAR is restricted to a smaller subset nowadays. EAR is still painful but much less than ITAR - if you just want to use an EAR product and you are in a NATO country, handling the restriction is fairly smooth.

No need for that actually. They will deorbit within a year if left completely dead, and within a couple of month if they have a single button "start deorbiting" that uses the electric propulsion.

But more importantly, their propulsion allows them to launch at a very low orbit. This is a very good method for a constellation as they can see all the early failures (the beginning of the bathtub curve) happen at a very low orbit and reduce the cost of ground testing.

Their orbital debris management strategy is one of the best I have seen.

I've had a few where the skip button was not available. Clicking on the button would just pause the ad.