New ventures into rocket reusability

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Alex van Stekelenborg (

Alex van Stekelenborg (

The main problem with today’s rockets is the enormous waste of material. Most parts of a rocket fall off and either burn falling through the atmosphere, crash land into the ocean, or float off into space forever. To put this into perspective, the Saturn V rocket weighed 6,540,000 pounds, but only had a payload of 310,000 pounds [1]. That’s 95.52 percent of the rocket going to waste by falling off into space, never to be used again, turning into space debris. It’s like having to buy a new car every time you want to drive somewhere. Saturn V, perhaps the U.S.’s most famous rocket, had to be rebuilt thirteen times to be launched thirteen times. A total of 6.417 billion dollars (approximately 41.3 billion dollars in 2015) were allocated to the production of the Saturn V rockets. That’s almost 500 million dollars (more than 3 billion dollars in 2015) per launch. [1] After the U.S. managed to land on the moon before any other country, the space race had ended and the government had much less of a justification to fork out the tremendous of money it was spending on NASA. Since 1966, NASA’s budget has decreased by 89 percent. NASA only has 0.5 percent of the U.S. budget to use which has staggeringly slowed the motivation for space exploration. This is where Elon Musk stepped in. Initially, Musk had wanted to buy rockets from Russian space companies to take the first steps towards colonizing mars and to regain public interest in space exploration. The only setback was the price of the rockets that the Russians were selling.
“The vodka shots started -'To space!' 'To America!' - and, a little buzzed, Musk asked point-blank how much a missile would cost. 'Eight million dollars each, they said. Musk countered, offering $8 million for two. 'They sat there and looked at him,' Cantrell, Elon’s associate that was with him at the meeting, said. 'And said something like, 'Young boy. No.' Musk stormed out of that meeting, and on the plane home began devising a plan to create his own rockets.”[2]

Eight million dollars was seen by Musk as much too expensive for an old rocket, so he had the ambitious idea to build his own rockets. He figured out that the materials for a rocket were only three percent of the sales price. On that notion, he founded SpaceX. He had a new idea: the reusable rocket. First began production of his own rocket, the Falcon 9. The Falcon 9 was a completely expendable rocket very similar to the Saturn V, but production costs were a fraction of what they were compared to NASA’s rockets. The cost per launch of the Falcon 9 is 61.2 million dollars,[3] which pales in comparison to the Saturn V’s 500 million dollars per launch. Being able to reuse thrusters from previously used rockets cuts down enormously on production costs, as it is no longer necessary to create new parts for every rocket launch. After being the first company to successfully dock and resupply the International Space Station in 2012, SpaceX began work on the reusable versions of its rockets. The Falcon 9-R was born [3]. The 9-R is the final step in creating the perfect rocket. SpaceX had to create a special rocket that would not only be able to withstand the destructive power of the earth’s atmosphere, but also be able to land vertically on a barge in the ocean. SpaceX is extremely close to finishing this technology. In development since 2011, the Falcon 9-R functions on an attitude control system that keeps the rocket in a vertical position throughout its entire descent with the use of horizontal thrusters. Many problems can occur while in the extreme descent of the rocket. In a test in September 2013, the rocket began spinning at high speeds, which in turn turned the gas chamber into a centrifuge, slung the gas against the walls of the chamber, and shut down the engine. [3] A new heatshield that was able to resist higher temperatures than NASA’s was developed to withstand the atmosphere’s extreme frictional heat. SpaceX had to figure out how to how to reignite the Falcon 9-R’s thrusters at supersonic and transonic velocities, and successfully did so by creating the restartable ignition system which slowed the Falcon 9-R down completely during tests. All these new technologies, once perfected, will create a Falcon 9-R that can resupply the international space station, send astronauts to the international space station, and then come back down to earth safely to do the same thing again.

As an engineer working on the Falcon 9, there are two pros and cons to the use of a reusable rocket. The pros obviously are reusability and massively decreased productions costs due to not having to reproduce every part of the rocket. However, it’s the cons that always have to be taken into account when engineering a new idea and actually bringing it to life.

I am a mechanical engineer working on the creation of the fully reusable Falcon 9 for SpaceX. I’m working with a seven person team of some of the best chemical, electrical, and mechanical engineers in the United States who are collaborating with me to come up with a perfect system. The two chemical engineers are developing a lightweight metal body for the rocket so less energy is used in moving the rocket, the two electrical engineers are installing the circuits that control the rocket’s programming, and the three mechanical engineers, including me, are modelling the rocket in a 3D computer modelling program to create the most efficient and aerodynamic rocket body. We are putting such an effort into creating a reusable rocket because there is no other ethical way to continue space travel.

There is a common English saying that goes “just because you can, doesn’t mean you should.” In other words, not every idea that someone has should actually come to fruition. That common English saying is the premise upon which all engineering ethics and codes of conducts are built upon. It is that code of ethics that is giving me and my team of mechanical engineers at SpaceX a very hard time at completing the development of the Falcon 9.

The codes of ethics that keep me from completing the rocket are the NSPE and ASME codes. Although they are obstructing me from easily finishing my project, it is these codes of ethics that are necessary to uphold the safety and usability of everyday products. “Engineers shall hold paramount the safety, health and welfare of the public in the performance of their professional duties.” [4][5] This the first and most and important of six fundamental canons of the both of the engineering societies that I belong to: the National Society of Professional Engineers and the American Society of Mechanical Engineers. As of now, it is only the first canon that currently applies to my situation. The rest of the code of ethics do not apply to my work: I’m working in my field, have no reason to commit any deceptive acts, I’m not required to make any public statements, I would never betray SpaceX and I trust my employer, and I work honorably, responsibly, and ethically.

The difference between me and an engineer that doesn’t follow any code of ethics is that the engineer without a code of ethics is not even an engineer in the first place. Taking shortcuts, bypassing safety precautions, and creating new things simply for self-gain does not make you an engineer; it makes you someone who’s willing to put others at risk for their own advantage.

I noticed how grave ethical problems can be in the engineering world through discovering and reading about several case studies. The one took that I took the most from was the Engineering Ethics in Spain: The Risky Tank. The situation is quite similar to mine, where an engineer is faced with a problem that would put the livelihood of others at risk. Continuing with his project could put the workers in danger. It is easily avoidable but his employer needs the project done as soon as possible. I would never put any one in danger, and that’s what I took away from the case study. More than 20 percent would have told the authorities about the business malpractice and another 20 percent would have put in additional safety measures. The majority of engineers that participated in the case study would not have continued with the work. This showed me how well almost all engineers follow the codes of ethics and the case study only cemented my belief that any ethical problems with the Falcon 9 must be fixed.

The idea for the Falcon 9 was first proposed in 2006. [5] The project has already been in development for nine years now and we only have come up with a partially reusable rocket. Even though the rocket is only partially reusable so far, it has already cut costs of rockets immensely, as stated previously. But that is the problem that we are running into as engineers that live by a code of ethics. The definition of a partially reusable rocket as of now is that our rockets come back down to earth, but not in one piece. Actually, they come down in half a piece. The rocket launches into space, drops off one of its booster-thrusters in orbit, and the rest of the rocket comes down. This might not seem too bad, however, the consequences of dropping of space junk could be disastrous, especially with the introduction of the Falcon 9 rocket. In the current day and age, the frequency of rocket launches per year is small, with an average of 75 for the past ten years. [6] With the introduction of the reusable falcon 9, the amount of flights per year could quadruple [5]. Some see this as a breakthrough in spaceflight, but as engineers we have to see the situation from every possible angle.

When in orbit around the earth, any object will object will have an average velocity of around 10 kilometers per second, or 6.2 miles per second. [7] This means that any object orbiting our planet has an enormous amount energy, so even with small objects, like a fleck of paint that could have peeled of a rocket, can behave like kinetic missiles. In fact, that is exactly what happened in 1994, when a fleck of paint struck the front the Challenger Space Shuttle’s windshield, creating a crater halfway through the entire windshield. [8] That was just a fleck of paint. There are currently more than 19,000 pieces of space junk greater than five centimeters and more than 300,000 pieces of space junk greater than 1 cm. It is impossible to track the amount the amount of debris the size of paint flecks as there are so many and they move at such a high velocity.

Sometime satellites themselves are threats to each other. In 2009, the Russian satellite Kosmos-2251 collided with the commercial satellite Iridium at 26,170 miles per hour. The collision resulted in more than 2,000 pieces of debris more than 4 inches across, which increased the amount of large space debris by ten percent. [9] As you can see, just one collision can return catastrophic effects.

In fact, this was exactly what NASA scientist Donald J. Keppler had predicted in 1978. His theory, now appropriately know as Kessler syndrome, was that the in space debris would eventually accumulate enough to start colliding with itself, resulting in even more space debris. More and more debris is created, creating a runaway chain reaction that could clutter low earth orbit entirely. This would make it almost impossible to send out any more satellites as they’d immediately get destroyed by space debris of any size. [10]

All of the space debris we have now is from the past 50 years of space exploration through the use of expendable rockets. The way this ties into the Falcon 9 rocket is that the Falcon 9 rocket is partially reusable. This means that the Falcon 9 will drop off its primary thruster every time it reaches space. The thrusters are extremely large parts of the rocket that are very heavy, so with the massive increase in possible rocket launches, the space around the earth will become massively cluttered with all the thrusters that will separate from.

Not only will this result in a cluttered space but the risk of injury and even death of every astronaut will increase to the point where it will simply be too dangerous to send any rockets at all into space. With empty thrusters orbiting at extremely high velocities, the chance of getting struck by an entire thruster or even just a piece of a thruster increases and that is not something that the engineers here at SpaceX can be responsible for. These are the types of problems that on runs into often when following the code of ethics. One could simply ignore the problem that detaching the thrusters creates and continue with the rocket launches for profit. Of course I have thought of doing that, but I would never actually be able to do it as being a true engineer takes all of the six canons of the code of ethics into account with any new possible ideas.

To satisfy the ASME and NSPE code of ethics, the Falcon 9 would have to be fitted with a completely reusable body that does not leave behind any debris in space whatsoever.

Luckily, since the production of the Falcon 9 has been slowed down due to the problem of space debris being ejected, we’ve had many years to think of new ideas for a completely reusable rocket. Initially, we thought a simple parachute would be able to slow down the rocket’s descent through the earth’s atmosphere. Unfortunately, we were wrong and on several different trials we our idea was disproven as the rocket burnt up due to the massive amount of friction from the air.[11] Our CEO Elon Musk proposed a new idea for the realm of rockets: the VTVL system. The VTVL system, which stands for vertical takeoff vertical landing, would enable the Falcon 9 rocket to not only take off like a normal rocket, but also land in the same position that it started at. Currently, we have a prototype called the Grasshopper that is much smaller than the Falcon 9 but successfully has taken off and landed several times. We have tested the same system on the Falcon 9 rocket and have come very close to a successful controlled landing, but haven’t yet completed a true full landing. [12] Nonetheless, every day we are getting closer and through the more tests we are taking.

There have been many other ideas proposed as alternatives to reusable rockets, like space elevators, [13] but these are simply not feasible with the technology we have today.
With the Falcon 9’s current system of dropping off its thrusters into orbit, it would not be ethical to send any more of the rockets into space. The debris in space can pose a deadly threat to any future astronauts and to the missions that they are set to carry out. The development of a completely reusable Falcon 9 rocket is essential to any future rocket launches as it will not only lower the cost of launches, but halt the increase of debris in the space around our planet, making space travel much safer and reliable for any astronauts of the future. This should be an example to learn from for any future engineers. I learned that the easiest way to accomplishing a great feat is not always the correct way to go about doing something. One must consider every aspect of what one is engineering and how those aspects will affect the world around, not only in the present, but also in the future.

[1] Rogers, Simon. "Nasa Budgets: US Spending on Space Travel since 1958 UPDATED." The Guardian. 1 Feb. 2010. Web. 6 Oct. 2015. (Newspaper)

[2] Zolfagharifard, Ellie. "Russian Space Bosses SPAT on Elon Musk When He Tried to Buy a Rocket." Dailymail. Associated Newspapers, 14 May 2015. Web. 6 Oct. 2015. . (Blog)

[3] "Capabilities & Services." SpaceX. Web. 6 Oct. 2015. . (Website)

[4] Code of Ethics. (n.d.). Retrieved November 2, 2015, from

[4] Ethics in Engineering. (n.d.). Retrieved November 2, 2015, from

[5] Frankel, D. (2010). Meeting Minutes.

[6] Space Calendar. (n.d.). Retrieved November 2, 2015, from

[7] NASA Orbital Debris FAQs. (2012, March 1). Retrieved November 2, 2015, from

[8] Christiansen, E. L., J. L. Hydeb and R. P. Bernhard. "Space Shuttle debris and meteoroid impacts." Advances in Space Research, Volume 34 Issue 5 (May 2004), pp. 1097–1103

[9] Iannotta, Becky (February 22, 2009). "U.S. Satellite Destroyed in Space Collision". Archived from the original on 13 February 2009. Retrieved 12 February 2009.

[10] Donald J. Kessler and Burton G. Cour-Palais (1978). "Collision Frequency of Artificial Satellites: The Creation of a Debris Belt". Journal of Geophysical Research 83: 2637–2646.

[11] Bergin, C. (2009, January 12). Musk ambition: SpaceX aim for fully reusable Falcon 9. Retrieved November 3, 2015, from

[12] Norris, G. (2014, April 28). SpaceX Plans For Multiple Reusable Booster Tests. Retrieved November 3, 2015, from

[13] ISEC. (2012, April 11). Retrieved November 3, 2015.

[14]Case 1041 Engineering Ethics in Spain
Stanford Biodesign - Resources. (n.d.). Retrieved November 3, 2015.

K.S. Mangan. (2006). Chronicle of Higher Education. January 27. "Professor Sued for Revealing Data."


Alex Johnson for answering any questions I had.

Pitt Excel for helping me push through the difficult times I’ve had.

University of Pittsburgh

Swanson School of Engineering

2015-11-03 1

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