The 2018 American Solar Challenge race starts tomorrow, running from Omaha, Nebraska to Bend, Oregon. Top contenders include university teams from Michigan, Poly. Montreal, (California) Berkeley, and Western Sydney. Follow the action at twitter.com/asc_solarracing?lang=en And here is a tracking site for the cars.
Updates: (July 15): After the first stage (two days) of racing, the top three teams are Michigan, Western Sydney, and Poly Montreal. About a minute separates the top two teams. The cars are following the historic Oregon Trail, which now begins to climb gradually into the mountains.
(July 18, evening) Early tomorrow, the cars will reach Atomic City and then pass through a corner of the Idaho National Laboratory (INL) en route to Arco. Several historic nuclear reactors are located here, including the Experimental Breeder Reactor One (EBR-I), which is now a National Historic Site; and EBR-II. The INL will also host the first small modular reactor by NuScale.
(July 20, afternoon) At about 1pm PDT, Michigan and Western Sydney, the leaders, crossed into Oregon.
In about 12 hours, there is going to be an amicable shootout in the high desert of eastern Oregon between the solar car teams of Western Sydney University and the University of Michigan. After battling each other across half a continent, with Michigan leading most of the way, WSU has now pulled ahead by about 8 minutes with ~125 miles (~200 km) to go. The final sprint starts, I believe, at around 9.00am PDT tomorrow morning. (See previous comment for links.)
(Update, July 23) Western Sydney did win the American Solar Car race (Aussie, Aussie, Aussie!) followed by Michigan and ETS (Quebec), but there were few losers. On ASC's twitter page scroll down to the beginning of Jul 22, then scroll up to see pictures of each team crossing the finish line. Great cars and great people.
Here are a few samples: "pure jungle cat", "European marques perennially atop the sport sedan podium are about to have trapdoors release beneath them.", and "[magnificent, a...spaceship,] obviously representative of the next step in the history of autos."
Post by Roger Clifton on Aug 6, 2018 10:05:17 GMT 9.5
Further to the comment on the Boeing small launch vehicle program, in which an (air-breathing) aircraft would ferry a multistage rocket up to 30 km altitude and release at a sub sonic velocity. There, the (oxidant-carrying) rocket stages would accelerate the spacecraft to orbital altitudes and orbital velocity.
Orbital velocity is easy to define, if difficult to achieve, 7.8 km/s. Minimum orbital altitude is harder. Theodore von Kármán calculated that the atmosphere around 100 km becomes too thin to support aeronautical flight, since an aircraft at this altitude would have to travel faster than orbital velocity to derive sufficient aerodynamic lift to support its mass against gravity. Since he was the chap who founded JPL, he oughta know. But you have to wonder if he was joking – after all, if you're travelling at orbital speed, your centrifugal force is already matching your weight. A vehicle travelling at orbital speed doesn't need any lift at all! Nevertheless, the "Kármán line" is considered to be the boundary between atmosphere and space. (However, some satellites on elliptical orbits will dip down through 80 km, tolerating the low drag during their useful lifetime.)
The Kármán line is not necessarily the limit of air breathing flight between destinations on the Earth's surface. It is true that you need so many kilograms per second of air flowing over your wings to give enough lift, and so many kilograms per second of oxygen flowing into your scram jet to provide thrust and thus lift. However, since the vehicle is near weightless (weight minus centrifugal force) around these speeds, it doesn't need much lift anyway. It can coast. Such high altitude flight would seem to be remarkably fuel-efficient.
Conceivably, a commercial aircraft could enter a suborbital trajectory at 50 km or so, and carry its near-weightless passengers towards a distant re-entry point with the minimum consumption of fuel.
Coincidentally, in about four hours (at around 1:18 am EDT) SpaceX is going to re-launch one of its new, highly reusable rockets. Those interested can watch the launch here. If, as the article reports, the company can reuse each rocket up to 100 times, both the cost and the embedded energy of each launch will drop significantly.
Update: The satellite was successfully deployed and the first stage landed safely for use again later this year. A recap of the mission.
"Tesla took longer than expected to ramp the production of the Model 3, but now the company is finally hitting its manufacturing stride, and the electric sedan is starting to make waves in the US auto industry--some very serious waves."
"It's the second time a Tesla product has won our annual award, which was captured by the Tesla Model S in 2013.
"Many have called the Model 3 Tesla's 'iPhone moment.' But that was the Model S--the shock to an auto industry that had dismissed its very premise as unfeasible. The Model 3 looks well beyond that. It's a brave, distinct product that makes no attempt to measure up to anything else on the road. And in some ways, it's the future."
"Nearly one year ago, McLaren's top engineer departed the British supercar-maker for a relatively unknown EV startup, Rivian, located 3000 miles away in Plymouth, Michigan.... While leaving ultra-high-performance supercars behind seemed crazy at the time, a whole band of McLaren engineers have now followed Vinnels to build world-class electric SUVs and pickups at Rivian."
Ahead of it were the #1 Toyota Camry (24, 545 units), the Honda Accord, the Toyota Corolla, the Honda Civic, and the Hyundai Elantra (18,148). But among midsize sedans, the most important segment of passenger cars, the Model 3 was third, trailing only the Camry and the Accord.