Viewing profile — ggreer

I'm trying to address one very specific point: Whether Starlink is profitable. I'm not trying to litigate other business practices. The development timeline for a different's compa…

The income/profit numbers I used include depreciation, and even if you subtract all space capex from Starlink income, the program would still have a profit of $482 million last qua…

The article about atmospheric pollution from deorbiting satellites leaves out the biggest source of stratospheric aluminum oxide: Solid rocket boosters. A single Ariane 6 launch cr…

How is Starlink financially unsustainable? In 2025, Starlink generated $4.42 billion in income from $11.39 billion in revenue. Last quarter Starlink generated $1.6 billion in incom…

I thought the idea behind exoskeletons and fancy wheelchairs was that they allow handicapped people to go more places, not to substitute for better infrastructure. I haven't seen a…

I was obviously referring to the surface of the moon, where impacts happen. It is impossible for liquid water to exist on or near the surface, as the lack of atmosphere means that …

Yes. There is no liquid water on the moon. There is no atmosphere. No life can exist there. The moon is struck by meteors quite frequently. The Lunar Reconnaissance Orbiter noticed…

Like most upper stages, Falcon 9 makes itself inert after a mission by venting any remaining propellant. Otherwise there's a risk that propellant could boil off, increasing pressur…

The moon is a lifeless rock with nobody on it. That seems like a better place for garbage to go than the earth. And since it's going to impact the moon at 2.43km/sec, I don't think…

The ship had a little over 34 tons of payload, but there should be almost no difference in thrust to weight ratio at launch for an empty vs full payload bay. The stack itself weigh…

Does this mean you think Starship HLS will fail? It will use a steel structure and is planned to be part of future Artemis missions. Also are you willing to stake money on that cla…

Aluminum alloy and carbon fiber, because both have high strength to weight ratios. Steel is denser, so its specific strength isn't as high. But it retains strength at both lower & …

Solid motors are simpler, but I wouldn't say they're more reliable. It was the solid booster failure that caused the Challenger disaster, and solid booster failures that have cause…

I'm not sure how that would help. If you're descending it's probably to land, and then you can recharge the batteries with electricity from the ground. That would be more efficient…

The talk about AI water usage exists because in Karen Hao’s book Empire of AI , she got water usage wrong by three orders of magnitude.[1] For data centers that use water cooling, …

Increasing global electricity production by 1.5% (or 500 terawatt-hours) would also be a solution. Production from solar power increased by 600TWh from 2024-2025 and its rate of ad…

I agree with those comments and my vehicles are a 1990 Mazda Miata that I fixed up[1] & and a Model 3 Performance. The Model 3 looks boring, but is ridiculously fast. The Miata has…

Are they fast DC chargers or level 2 chargers? If it's the former, then that is cheap. If it's latter, then that is some expensive electricity. I'm in Washington where electricity …

I can think of several practical uses. It would be very useful immediately after a disaster. Lighting up the night would make search & rescue much more effective. It would also all…

I picked 30mph because that's the current threshold for what is considered a motorcycle in the state of Washington. Until recently, e-bikes were exempt from this because the old la…

The law doesn't ban them. It classifies fast e-bikes as motorcycles (which require registration, insurance, and a motorcycle endorsement).[1] This seems reasonable to me. The previ…

For sprints, shoes give additional traction for faster starts, but don't increase running efficiency. For distance events, shoes were just extra weight, and barefoot runners have w…

This quirk of competition is why swimmers can win a ridiculous number of medals. If swimming only had freestyle, Michael Phelps would have 7 gold medals instead of 23.

Allowing a bicycle would be like if swimming competitions allowed fins. A more accurate mapping to the swimming strokes would be race walking, which is widely ridiculed.

Space gets you 24/7 solar power. To run a data center for 12 hours without sunlight, you'd need massive batteries. Also oceans have weather and corrosion. The issue with putting st…