Introduced in , the Model T made gasoline-powered cars widely available and affordable. That same year, Charles Kettering introduced the electric starter, eliminating the need for the hand crank and giving rise to more gasoline-powered vehicle sales. Other developments also contributed to the decline of the electric vehicle.
By the s, the U. With the discovery of Texas crude oil, gas became cheap and readily available for rural Americans, and filling stations began popping up across the country. In comparison, very few Americans outside of cities had electricity at that time.
- Thermal efficiency.
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In the end, electric vehicles all but disappeared by Over the next 30 years or so, electric vehicles entered a sort of dark ages with little advancement in the technology. Cheap, abundant gasoline and continued improvement in the internal combustion engine hampered demand for alternative fuel vehicles. Fast forward to the late s and early s. Soaring oil prices and gasoline shortages -- peaking with the Arab Oil Embargo -- created a growing interest in lowering the U.
Congress took note and passed the Electric and Hybrid Vehicle Research, Development, and Demonstration Act of , authorizing the Energy Department to support research and development in electric and hybrid vehicles. Around this same time, many big and small automakers began exploring options for alternative fuel vehicles, including electric cars.
Even NASA helped raise the profile of the electric vehicle when its electric Lunar rover became the first manned vehicle to drive on the moon in Yet, the vehicles developed and produced in the s still suffered from drawbacks compared to gasoline-powered cars. Electric vehicles during this time had limited performance -- usually topping at speeds of 45 miles per hour -- and their typical range was limited to 40 miles before needing to be recharged. Fast forward again -- this time to the s.
In the 20 years since the long gas lines of the s, interest in electric vehicles had mostly died down. But new federal and state regulations begin to change things. The passage of the Clean Air Act Amendment and the Energy Policy Act -- plus new transportation emissions regulations issued by the California Air Resources Board -- helped create a renewed interest in electric vehicles in the U. During this time, automakers began modifying some of their popular vehicle models into electric vehicles. This meant that electric vehicles now achieved speeds and performance much closer to gasoline-powered vehicles, and many of them had a range of 60 miles.
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Instead of modifying an existing vehicle, GM designed and developed the EV1 from the ground up. With a range of 80 miles and the ability to accelerate from 0 to 50 miles per hour in just seven seconds, the EV1 quickly gained a cult following. But because of high production costs, the EV1 was never commercially viable, and GM discontinued it in Depending on whom you ask, it was one of two events that sparked the interest we see today in electric vehicles. So which is better? For a single stage to orbit, hydrogen is the best option. If, on the other hand, your rocket uses multiple stages during its climb to orbit, RP-1 might be a better bet for the core stage.
The efficiency of a rocket engine—essentially, how much change in velocity it delivers per quantity of propellant consumed—is measured in seconds of specific impulse, a metric known as Isp. The RS, burning hydrogen, is more efficient, at seconds. An in-between option is liquid methane. Glenn Case told me that in theory, methane offers about ten more seconds of Isp over RP Methane doesn't need to be as cold as hydrogen, which makes it easier to work with.
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It also burns cleaner than RP-1, making it attractive for reusable engines. Both of those engines will also employ closed-cycle designs, giving them increased performance.
Coincidentally, that's about the same price SpaceX advertises for an entire Falcon 9 flight. SLS and the Falcon 9 are two very different launch vehicles bound by separate programmatic and technical constraints. But there's no way around the glaring truth that SLS is incredibly expensive. Aerojet says they plan to reduce the cost of the RS by 33 percent. The savings will come from modernizing production lines to increase efficiency, as well as advances in materials science. Steve Wofford said engineers can now forge and cast large engine parts more precisely, rather than casting rough shapes and spending thousands of hours machining them to their final forms.
Another cost-saving technique is the utilization of additive manufacturing, or 3-D printing. So is a 33 percent cost reduction realistic? There's one more engine selection factor that arguably carries as much weight as all others combined: politics. The NASA Authorization Act of legally requires SLS to be built using space shuttle-derived technology, and to utilize the shuttle program's workforce where practical.
The story behind the Act is complex, but it passed the Senate unanimously, cleared the House by a margin of to , and was signed into law by President Obama. This combination of requirements narrowed the engine selection field significantly. But the engine has never carried astronauts. NASA and Aerojet would have had to find ways to make it safer and more reliable, adding costs. NASA also could have started from scratch, but that would have been even more costly and time-consuming. Plus, there was the whole shuttle workforce aspect of the Authorization Act to contend with, and the law said SLS should be operational by the end of —a deadline NASA is already going to miss.
That really left only one option: the RS So you've got to balance that investment with developing a whole new engine. Glenn Case agreed. While he preferred not to side with any particular rocket configuration, he said it was hard to argue against the RS For now, those spacecraft will remain tethered to low-Earth orbit, ferrying crews back and forth to the International Space Station.
But SpaceX recently announced the Crew Dragon won't be bound there for long. The company is on the cusp of debuting the Falcon Heavy, essentially three Falcon 9 rockets bolted together, capable of launching a whopping 54 metric tons to low-Earth orbit. That will eclipse the capability of all current launch vehicles except SLS. Details have yet to be publicized, and the space firm's timelines often slip.
But given SpaceX's continuing run of impressive successes, it's hard not to take the pledge seriously. The law was a compromise between a presidential administration that wanted to radically change NASA's direction and a Congress that was unwilling to strongly deviate from business as usual. Space policy doesn't play a large role in presidential elections.
But soon, a new administration will have the opportunity to tweak NASA's direction. Rocket science, when greenlit to proceed, is largely immune to politics. Two more RSs will be in the test stand this year at Stennis, and next year, the Space Launch System's entire core stage will rumble to life for a test in the Mississippi bayou. For now, the RS remains the current heavyweight champion of the rocket engine world, and it looks to keep that title for the foreseeable future. Read more: SLS , Orion , human spaceflight. Become a member of The Planetary Society and together we will create the future of space exploration.
My objection is to the use of solid rocket boosters instead of liquid boosters, and would love to see an article on the genesis of that decision, focusing on other factors than "because we legally have to give the business to Morton-Thiokol.
The Thiokol name hasn't been used for a decade. Nominally the system is supposed to allow for changing to other boosters, the politics prevents that at least for the initial two design blocks. I hope that some day that political requirement goes away before Block 2 gets locked in stone. Imagine, as boosters, using Falcon Heavys with side-reinforced core stages for the attachment, one Falcon Heavy for each side. Or, more simply, just six of the Falcon Heavy's boosters arranged in a ring around the core. And they're lighter.follow link
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And significantly higher ISP. And you get them back afterward, if you have enough landing infrastructure. I know some people would worry about that many engines, because of the N1.