Sweeney describes his conversations with the Tesla founder about the account and what he says Musk offered him to take it down.
By 2031 the ISS will have served as a continuous human habitation and microgravity lab in low-Earth orbit for more than 3 decades.
The ISS is 1,000 times closer to us than the Moon, and 600,000 times closer than Mars. To get to the latter and back safely, we need faster rocket propulsion systems.
Using the conventional chemical rocket technology we have perfected at this time, a single mission to Mars will require the launch of a mass equal to 10 ISS to be put into space. It will involve at least 30 and as many as 40 of the largest rockets we have today to put the spacecraft, crew and fuel needed for the mission. That doesn’t include adding reserves of fuel placed strategically along the route should a problem arise going to Mars and coming back. Brown states that the total cost of a single mission using this approach would exceed $80 billion using the yet-to-be-launched SLS as the primary vehicle. With SpaceX and the Starship and Heavy booster, the cost could be cut by half. But even $40 billion for a single mission seems excessive.
Using nuclear-powered propulsion systems, however, would eliminate the need to put megatons of fuel into orbit. The only time chemical rockets would be used would be in launching the crew and spaceship components to Earth orbit. That could be done in as few as three launches with the final assembled ship going to Mars and back and then being parked in Earth orbit to be used again on future missions.
What additional advantages can be derived from using nuclear? Thermal-powered nuclear is at least twice as efficient as current chemical rockets and requires a tiny fraction of the fuel to get the job done. Electric-powered nuclear starts moving the rocket slowly away from Earth and then continuously accelerates to attain peak speeds of 200,000 kilometres (120,000 miles) per hour. An electric-powered nuclear propulsion system would use even less fuel than thermal-powered nuclear and would shorten the voyage to a month.
It has elasto-magnetic properties that cause it to react to external forces or energy acting like a super rubber band.
Paroxysmal AF occurs when the upper chambers of the heart beat irregularly. Instead of initiating normal sinus rhythm, the two atria fibrillate or quiver. That doesn’t stop blood flowing from the upper to lower chambers, but it does upset the normal heartbeat causing the heart to race. In my case, the paroxysmal reference meant that my heart was going in and out of AF. Sometimes everything was normal. At other times I would experience a racing heartbeat exceeding 120 beats per minute and lasting from minutes to hours.
When an AF episode ends what happens inside the heart? An apt analogy is the electric control panel in every home that either contains circuit breakers or fuses. When lights go out you can go to the box to reset a tripped circuit or replace a blown fuse. In Paroxysmal AF that reset is automatic with the heartbeat returning to normal sinus rhythm.
So where does conversion come into the conversation? I had worn a Holter Monitor (a portable ECG device) for 14-days back in the latter part of November of last year. In this pandemic-disrupted world, it took a while before a cardiologist got back to me about what the Holter showed. In a video call last week I learned about conversion in an entirely new context. The cardiologist told me that over the two weeks of wearing the Holter Monitor I had been in AF for 8.5% of the time and had experienced seven conversion pauses lasting between 3.5 and 5 seconds. A pause is exactly what you think it means. If we carry the analogy of the fuse box, it is as if a power fluctuation caused the lights to go out and it took five seconds to reset the circuit breaker for them to come back on. The cardiologist said the AF occurrences were less of a concern than the conversion pauses, particularly one lasting 5 seconds (apparently happened in my sleep).
Researchers using crushed concrete from demolished buildings to make calcium carbonate cement. Could reduce GHGs in the atmosphere by 2%.
The Sun’s solar activity cycle moves into high gear and knocks down 40 Starlink satellites. Peak is 2025. How many more could be impacted?
Researchers from Stanford University developed a robotic gripper that uses gecko-inspired adhesives to pick up both delicate and robust objects. An earlier concept was tested aboard the International Space Station in May 2021 to see its potential.
