シャドーイング練習: Why SpaceX and NASA Rockets Are So Different - 動画で英語スピーキングを学ぶ

Let’s start by acknowledging something crucial.  Although NASA and SpaceX are both at the forefront of space travel, their rockets look entirely  different, and that is mainly due to the fact that they have very different goals. Imagine packing  for a trip to the edge of the solar system- that is the kind of durability NASA is thinking  about. They need materials tough enough to withstand the “unknown”. That is why NASA relies  on advanced materials like aluminum-lithium alloy, known for being both lightweight and incredibly  strong. This allows their Space Launch System (SLS) to survive intense forces of a rocket  launch, and the hostile environment of deep space.

Meanwhile, SpaceX isn’t playing that same  long game, and are taking a completely different approach. Instead of one time  use rockets like NASA’s, they are laser focused on getting rockets to fly multiple times  without starting from scratch. Their Starship, made from stainless steel, can handle extreme  heat, especially during re-entry. That’s why you’ll often hear Elon Musk comparing space  travel to airplanes. Think of it like your car. You wouldn’t drive it once and then  throw it away right? You don’t throw away a plane after one trip, you fly it again.  With Starship, the goal is to reduce the cost of launching into space by using the same  hardware over and over, and that’s not all.

NASA’s SLS uses heat shields that burn away during  re-entry, like peeling off a layer of skin each time it comes back to Earth. SpaceX’s Starship?  It uses heat-resistant ceramic tiles that stay intact, giving the spacecraft multiple chances  to prove itself. This isn’t just a difference in materials; it’s a completely different design  philosophy. But what makes SpaceX so obsessed with getting more bang for your buck, while  NASA sticks to its more traditional designs?

The answer lies in how they both operate,  and of course, where they get their money.

Now you may ask: how does the funding of  a government agency like NASA differ from a private company like SpaceX? Well, here’s a  question for you. What if your entire business model was based on never running out of money?  Think of NASA as the slow and steady marathon runner. Its funding comes from the U.S government,  which gives them a steady stream of resources, allowing NASA to pursue ambitious long term  projects like sending humans to and from the moon, or even to Mars. But the trade off? NASA has to  align with government priorities and justify its spending to taxpayers, which can make their  process slower and more political. But here’s the thing. That level of funding allows NASA  to dream big without worrying too much about immediate profits. It's like having a safety net  that lets you try and try again, without the fear of losing balance and falling off. It allows  them to invest in groundbreaking technology and conduct extensive research, ultimately paving  the way for future generations of explorers.

On the other hand, SpaceX is more like a  high-speed sprinter, constantly racing to innovate and stay ahead. As a private company,  they don't have the luxury of guaranteed funding.

Every launch and new contract has to bring  in enough money to keep the lights on. So while NASA can afford to play the long game,  SpaceX has to be scrappy and efficient. They need to keep their costs low and find ways to  make their rockets cheaper to build and fly, which is where the reusability comes in. Using  the same rocket multiple times isn’t just a neat trick; it's a necessity. SpaceX’s financial  model depends on this to stay competitive, which has now become a constant pressure to  innovate, and has forced them to do things differently. This drive for efficiency  also extends their launch schedules, allowing SpaceX to conduct frequent missions, a  flexibility that NASA sometimes lacks due to the politics involved. But how does that impact their  rocket engines, the heart of any space mission?

Have you ever heard of NASA’s Saturn V Rocket?  You know, the one that took astronauts to the moon? That rocket had just five engines. Those  F-1 engines were massive, each one powerful enough to lift a skyscraper. But once the job was  done, they were discarded. A one time deal. Now, compare that to SpaceX’s Super Heavy Rocket,  which has 33 engines. Why so many? Well, it’s not only about raw power. Each individual  Raptor engine is smaller and less powerful than the F-1 engines NASA used, and generates a third  of the power required to achieve the necessary total thrust, so multiple engines are needed. Also, with that many smaller engines, SpaceX can afford to lose one or two during  launch and still make it to space. It’s like having a fleet of backup generators. If one  fails, no problem. The others can just pick up the slack. This gives SpaceX more flexibility  and control during launch and landing, which is critical for their focus on efficiency. Each  engine is designed to be fired multiple times, making Super Heavy the ultimate multi-use rocket  booster. This engineering allows SpaceX to rapidly test and create new technologies each time. But NASA must have seen how successful SpaceX is, spending less and getting more. Why does it insist  on sticking to larger, more powerful engines? It is mainly because NASA’s missions prioritize power  and reliability, especially for deep space. They are thinking about sending humans to distant  planets, not just getting them into orbit. The Saturn V engines, while single use, provided  unmatched power and reliability for that era.

SpaceX on the other hand, needs the flexibility  for frequent launches and landings. This is where the differences in their philosophy  about how space exploration should be done, shine. So now that we know how their engines  differ, let’s have a deeper look at the most vital difference between both organization’s  goals, which are reusability vs single use.

NASA’s older rockets like the Saturn V were  built for single use. After getting to space, their parts were discarded, like an expensive  one way ticket. But NASA wasn’t entirely stuck in this model. They did experiment with reusability  through the Space Shuttle program. The shuttle’s orbiter and solid rocket boosters were designed to  be reused, unlike the massive external fuel tank, which was discarded and lost after each flight. But here’s where things get tricky. While the Space SHuttle was groundbreaking in its attempts,  it wasn’t as cost effective as NASA had hoped. The high costs of refurbishing the shuttle after each  flight, combined with the tragedies of Challenger in 1986 and Columbia in 2003, led to the program’s  retirement in 2011. NASA had ventured into the world of reusable spacecraft, but found the  execution far more difficult than anticipated.

On the flip side, SpaceX has been all in on  reusability since day one. Their Falcon 9 and Starship rockets are built with the specific  goal of flying multiple missions. Like Elon said: “You can imagine that if planes were  not reusable, not everyone would fly”.

This mentality allows SpaceX to launch more  frequently and at a lower cost, appealing to commercial customers eager to cut expenses. Now, it’s interesting to note that NASA is starting to adopt some of these ideas, working  with SpaceX on reusable technologies for future crewed missions. This collaboration  could mark a significant shift in how both organizations approach rocket  design, potentially combining NASA’s reliability with SpaceX’s innovative spirit. But what’s intriguing is that SpaceX’s approach to design is influenced by more  than just economics. There’s yet another factor that just might surprise you, and  that, believe it or not, is pop culture.

Elon Musk admitted that part of the design  for SpaceX’s rocket was inspired by a comedy movie. Yes, you heard that right.  Specifically the scene from The Dictator, 2012, where the dictator critiques his engineer’s  missile design, prompting Musk to consider making SpaceX’s rockets more aesthetically pleasing. This playful attitude speaks to something bigger.

They aren’t afraid to take risks and challenge  norms, even if it means drawing information from unexpected sources. This is a huge contrast to  NASA’s more traditional, no nonsense approach.

While NASA follows tried and true methods to  ensure the safety of their missions, SpaceX is more willing to experiment and push boundaries. But, both approaches have their place in the evolving world of space exploration, and have  each led to breakthroughs that have significantly reduced the cost of access to space. NASA’s legacy  of meticulous engineering and SpaceX’s daring designs can encourage rapid progress for us humans  in general, and as they learn from each other, the potential for collaboration grows. But  let us not mistake collaboration with one being better than the other. In this world,  they can equally thrive in their differences.

NASA’s goal is clear: long term  missions, deep space exploration, and the technology to survive the unknown.  Their Artemis program aims to establish a lasting human presence on the Moon, preparing  us for the distant planets beyond. SpaceX on the other hand is racing to make space travel more  accessible to everyone, not just astronauts.

Two paths, two visions, and  both driving the future of space. But will they compete? Or will they  collaborate to reach the stars? Either way, buckle up cause the race is only  just beginning. Bye for now!

In this video, we delve into the fascinating  world of rocket design philosophy, specifically looking at the pros and cons of two  organizations at the forefront of space travel: SpaceX and NASA. While NASA focuses on deep  space missions with durable single use rockets, SpaceX prefers reusability, aiming to make  space travel as accessible as flying on a commercial airplane. We explore how these  differing philosophies shape their designs, from the materials used to  the engines that power them.

Discover how NASA’s commitment to safety and  reliability influences its engineering choices, leading to rockets like the Space Launch System  (SLS) designed for extreme conditions. In contrast, learn how SpaceX’s innovative approach  prioritizes flexibility and cost efficiency.

As we look to the future of space travel,  we wonder whether one approach will prevail, or if a partnership between the two is  inevitable. Join us on this journey as we explore what’s next for space exploration  and the exciting possibilities that lie ahead.