Los Angeles has plenty of sunny weather, and rain is pretty unusual. But recently, it was pouring rain, and we had taken a day off work. What to do? We took the opportunity to check out the local California Science Center! We had never been before, and it had a lot of great exhibits. I was primarily interested in the Air & Space exhibit, and the museum is also the permanent home of the Space Shuttle Endeavor.
replica of the viking lander on mars
The space exhibit is broken out into a few sections: air and aircraft; humans in space; the solar system and planets; and telescopes and stars. The “humans in space” part of the exhibit has some really impressive things on display, including an actual Apollo command module, a Gemini capsule, and a Mercury-Redstone capsule.
apollo command module
For those who are less familiar with the details, the US space program back in the 1950s and 60s involved the creation of NASA and several successively ambitious projects designed to accomplish specific goals or milestones:
gemini capsule
Project Mercury. Beginning immediately after the Soviet Union launched the first satellite into orbit (Sputnik in 1957), Project Mercury was the first human spaceflight program in the US and ran from 1958 to 1963. The goal was to put a man into orbit and, of course, return him safely. The program involved 20 spacecraft launches with no crew (some with an animal), and eventually it successfully launched humans into orbit.
Project Gemini. The purpose of Gemini (1961 to 1966) was to develop space travel techniques to support the ability to eventually land astronauts on the moon (which was ultimately done with Apollo). These techniques included things like extra-vehicular activity, rendezvous of spacecraft, and docking. The name Gemini comes from the fact that the spacecraft carried a two-person crew, named after the Gemini twins in Greek mythology.
Project Apollo. Running from 1968 to 1972, the goal of Apollo was to land the first astronauts on the moon. It involved a three person spacecraft and was originally conceived during the Eisenhower administration in the 1950s, but later dedicated to JFK’s goal of landing a man on the moon, and of course eventually achieved its goal with Apollo 11 in 1969.
space shuttle endeavor on display, front view
The highlight of the museum (for me, at least) was the Endeavor exhibit. The US only produced a total of six space shuttles, which were in operation from the first flight in 1981 through the last flight in 2011: Enterprise, Columbia, Challenger, Discovery, Atlantis, and Endeavor. The first shuttle, Enterprise, was only used for testing purposes. Two of the six shuttles, Challenger and Columbia, were lost in two disasters when they disintegrated during their missions, in 1986 and 2003, respectively. That means only four of the six shuttles are still in existence, and the California Science Center houses one of them. The Endeavor was gifted to the museum and, through seemingly herculean efforts, transported to southern California back in 2012.
It was pretty amazing to learn about the difficult journey to physically move the shuttle through the streets of Los Angeles, and to see one of the few remaining shuttles up close.
space shuttle endeavor on display, rear view
The space shuttle is currently on display in this building, but the museum is in the process of building another even larger building where the shuttle will sit vertically, attached to the booster tanks as if it were ready for launch. This will be the only place in the world where the shuttle will be displayed in this manner. I’m not sure when the exhibit will be completed, but it should be pretty impressive.
I didn’t grow up during the space race in the 1950s and 60s, but rather during the 1980s and 90s when the space shuttle program seemed like the future. Now, of course, it’s been retired and NASA is developing the Space Launch System, and private companies like SpaceX, Blue Origin, and others are building massive rockets to put humans into space (which SpaceX has already successfully done). But this exhibit really hit home for me; I was in awe at the experience of seeing one of the only space shuttles in existence. If you live in LA or are planning to visit, I’d definitely recommend a trip to the California Science Center.
New year’s day: seems like a good time for some updates.
during a brief trip to ojai
To say I’ve been busy lately would be a dramatic understatement. Even aside from the pandemic and the general chaos it has created, 2021 has been a pretty crazy year for me. At this time 1 year ago, we were living in the Seattle area and our daughter hadn’t been born yet. Fast forward to today, and she is 11 months old, and we are living in Los Angeles (with another big cross country move to come in another few months).
During 2021 I can’t say I accomplished much in rocketry, but I did take several classes at local community colleges: a chemistry prep course; the full chemistry course with lab; a geology class about dinosaurs; and linear (matrix) algebra. In 2019, I took the three-part calculus series, and linear algebra was the first post-calculus math class I’ve ever taken. I’d like to eventually get an engineering degree and these are just math and science pre-requisites, but regardless of whether I ultimately get the degree, I just enjoy learning – and these are some tough classes that really force me to do some hard work and expand my mind.
Since arriving in Los Angeles about six months ago, we’ve also made an effort to get out and explore the local area – with the important caveats that this is taking place during a global pandemic and we have a baby. We’ve made it to San Diego, Santa Barbara, Ojai, and Big Bear Lake within a few hours’ drive of LA; several beaches, many hikes, and a few botanical gardens; and much more. Most recently we just visited the California Science Center, which has an awesome space exhibit and actually houses one of the (now retired) space shuttles. I’ll post more about this exhibit shortly!
Can you have property rights in space? Can an individual, or a private company, or a government, claim territory on the moon, or on Mars? What about asteroid mining?
can you own this?
The short answer is: there isn’t settled law on these questions. And nobody has actually attempted it yet, so the law is all theoretical. But given aerospace developments in recent years, the question is increasingly important. Blue Origin, SpaceX, and other private/ commercial space launch companies have publicly stated they intend to land humans on the moon or Mars, or mine asteroids for resources. Other countries’ governments are developing and launching large commercial rockets (e.g. China). Property rights in space may become very significant.
International law and treaties
One complicating but fundamental starting point is that different countries (i.e. states) have their own laws. There isn’t a single overarching legal framework, but rather just individual countries’ laws. Sometimes, multiple countries sign a mutually binding treaty and create an “international” law, but this is a fuzzy concept. Some might argue that there’s no such thing as international law, really, since there’s not a single international or world government. For that reason, it frequently may not be properly enforced. The United Nations is an example of this.
Furthermore, each country can choose to sign onto an international agreement or treaty, and not every country does – so some countries may not join the agreement, and can effectively do whatever they want.
That said, agreements and treaties among countries do exist, and are treated as binding with legal obligations. Below, I mention a few of the key treaties.
The 1967 Outer Space Treaty
Back in 1967, when the United States and the Soviet Union had competing space programs but neither had yet landed a human on the moon, a treaty was entered into among both countries and the United Kingdom. Formally known as the “Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies,” it is generally shorthanded as the 1967 Outer Space Treaty, and it forms the basis for international space law. The treaty was entered into and became effective in 1967 with the US, USSR, and UK, but as of 2021, well over 100 countries are parties to the agreement (about 111 have signed and ratified it, while another 23 have signed but not yet ratified). The United States is one of these parties.
In general, this is an arms control or “non-armament” treaty, meaning that it basically prohibits countries from putting weapons of mass destruction (including nuclear weapons) in space or establishing military bases on celestial bodies. Instead, it limits use of the moon and other celestial bodies to peaceful purposes only.
The treaty is actually fascinating and, in some respects, way ahead of its time. Key passages from Article I include:
The exploration and use of outer space, including the Moon and other celestial bodies, shall be carried out for the benefit and in the interests of all countries, irrespective of their degree of economic or scientific development, and shall be the province of all mankind.
Article I, sentence 1
Outer space, including the Moon and other celestial bodies, shall be free for exploration and use by all States without discrimination of any kind, on a basis of equality and in accordance with international law, and there shall be free access to all areas of celestial bodies.
Article I, sentence 2
There shall be freedom of scientific investigation in outer space, including the Moon and other celestial bodies, and States shall facilitate and encourage international cooperation in such investigation.
Article I, sentence 3
Section II discusses the principle of non-appropriation:
Outer space, including the Moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.
Article II
Finally, worth highlighting here, section VI of the treaty discusses international responsibility:
State Parties to the Treaty shall bear international responsibility for national activities in outer space, including the Moon and other celestial bodies, whether such activities are carried on by governmental agencies or by non-governmental entities, and for assuring that national activities are carried out in conformity with the provisions set forth in the present Treaty.
Article VI, sentence 1
The activities of non-governmental entities in outer space, including the Moon and other celestial bodies, shall require authorization and continuing supervision by the appropriate State Party to the Treaty.
Article VI, sentence 2
It’s not really clear whether an activity like asteroid mining would be permitted under this treaty. It states that the moon and other celestial bodies are not subject to appropriation, but it also says that they must be free for exploration and use.
The Moon Agreement
This agreement applies to the moon, but also to all other celestial bodies within the solar system (i.e., everything other than the earth), and it went into effect in 1984. What’s perhaps most important to note is that as of 2021, there are only 18 countries that are parties to the Moon Agreement (and another 4 that have signed it, but have not yet ratified). None of them are spacefaring countries capable of orbital flight. This means, of course, the United States is not a party.
Similar to the 1967 Outer Space Treaty, the Moon Agreement states that the moon is not subject to any national appropriation. It says that the parties have the right to exploration and use of the moon. However, it goes further and says that neither the surface or the subsurface of the moon, or any of its natural resources, shall become property of any state, or any non-governmental organization, or any individual person. And placing any personnel, space vehicles, equipment, facilities, etc. on the moon’s surface or beneath its surface does not create any right of ownership over the moon. Again, these provisions apply to all celestial bodies, as well as the moon itself, which would include Mars and asteroids. But it wouldn’t be binding on the US or any individuals or organizations within the US.
The US Commercial Space Launch Competitiveness Act
In the US, private space launch companies started to lobby Congress to pass a law clarifying that they would be able to mine or harvest resources in space, whether from the moon, other planets, or asteroids. As a result of these efforts, Congress passed this statute in 2015. In an obvious and eye-rolling attempt to reverse engineer the law’s name to arrive at the desired acronym, it is also known as the Spurring Private Aerospace Competitiveness and Entrepreneurship (“SPACE”) Act. It expressly allows US citizens and companies to “engage in the commercial exploration and exploitation of space resources,” including water and minerals. The law states:
A United States citizen engaged in commercial recovery of an asteroid resource or a space resource under this chapter shall be entitled to any asteroid resource or space resource obtained, including to possess, own, transport, use, and sell the asteroid resource or space resource obtained in accordance with applicable law, including the international obligations of the United States.
Section 51303, Asteroid resource and space resource rights
As you might suspect, some people have argued that this US law violates the 1967 Outer Space Treaty. Right now, this is all very theoretical since nobody is actually mining or exploiting resources from space (yet). Which leads me to…
The Artemis Accords
In 2020, the Artemis Accords were signed as an international agreement between countries participating in the Artemis Program, which is the US-led program to return humans to the moon. About a dozen countries, including the US, have signed this agreement. The Artemis Accords state, in relevant part:
The Signatories emphasize that the extraction and utilization of space resources, including any recovery from the surface or subsurface of the Moon, Mars, comets, or asteroids, should be executed in a manner that complies with the Outer Space Treaty and in support of safe and sustainable space activities. The Signatories affirm that the extraction of space resources does not inherently constitute national appropriation under Article II of the Outer Space Treaty, and that contracts and other legal instruments relating to space resources should be consistent with that Treaty.
Section 10 – Space Resources
This is an attempt to bridge the gap between the 1967 Outer Space Treaty (which prohibits appropriation of the moon and other celestial bodies) and the 2015 US SPACE Act (which allows extraction of resources), by stating that “extraction of space resources does not inherently constitute national appropriation” under the Outer Space Treaty.
The 2015 US SPACE Act and the US-backed Artemis Accords have drawn some criticism for being too US-centric and protecting American interests in space. The bold assertion that extraction of space resources does not constitute appropriation (a violation of the Outer Space Treaty) is an interpretation of the treaty, but not necessarily the only or best interpretation. And importantly, the Accords are not really considered a “treaty” because they did not go through the United Nations’ treaty process – rather, they are just a series of bilateral agreements between the US and various other countries. In other words, they may or may not have any value in terms of being an official interpretation of the Outer Space Treaty.
Asteroid Mining
In conclusion – the 1967 Outer Space Treaty is the primary international law on point here, and it is not clear whether it allows or prohibits extracting resources in space. More recent and more specific US law says that it is allowed – but this could be challenged as a violation of the international treaty.
Assuming for practical purposes that mining or extracting resources from the moon or asteroids were attempted by an individual or private company in the US, additional questions would arise. Would you be required to obtain a permit or license from the US government? If so, which agency or department would grant the license – the FAA, which generally regulates air and space flight? The Department of Commerce, which regulates economic activity? Another agency?
None of this is clear today. But these are just some of the important questions that will need to be answered as companies like SpaceX or Blue Origin expand their space launch programs over the next few years.
Have you ever wondered what the rules are when it comes to rocket launches? A rocket is basically a bomb with a hole poked in one end, and they sometimes fail catastrophically. Are there any laws governing this activity, or is it a total free for all? Aside from exploding on the pad, what if your rocket (or parts of it) land on someone else’s private property or injured someone? Do you need some sort of clearance from the government to launch a rocket?
Volumes of books could be written with answers to these questions, but I will just highlight a couple of important federal laws and regulations that govern large commercial rockets and space launch activity in the United States. My background is in law, so it’s only natural for me to pay extra attention to the laws and regulations for space flight.
rocket lab launch. image credit: new york times
International Traffic in Arms Regulations
One fundamental set of requirements is the International Traffic in Arms Regulations (“ITAR”). These regulations restrict the export of defense or military related technologies, as a part of US national security. Here’s a quick rundown:
What type of technologies are covered under ITAR? Defense-related articles and services, which are on the United States Munitions List (“USML”). This is basically a list of services or technologies that have been designated as defense or space related by the US government.
What’s a defense-related “article”? An article is basically either a physical item or technical data.
What does it mean if a technology is on the USML and subject to ITAR? In order to export one of these technologies (i.e., to give it to a non-US person), you would have to get an export license from the US State Department. In other words, in general, these technologies can only be shared with another US person, unless you get special approval from the State Department.
What are the categories in the United States Munitions List?
Firearms, Close Assault Weapons and Combat Shotguns
Explosives and Energetic Materials, Propellants, Incendiary Agents, and Their Constituents
Surface Vessels of War and Special Naval Equipment
Ground Vehicles
Aircraft and Related Articles
Military Training Equipment and Training
Personal Protective Equipment
Military Electronics
Fire Control, Range Finder, Optical and Guidance and Control Equipment, Night vision goggles
Materials and Miscellaneous Articles
Toxicological Agents, Including Chemical Agents, Biological Agents, and Associated Equipment
Spacecraft and Related Articles
Nuclear Weapons Related Articles
Classified Articles, Technical Data, and Defense Services Not Otherwise Enumerated
Directed Energy Weapons
Gas Turbine Engines and Associated Equipment
Submersible Vessels and Related Articles
Articles, Technical Data, and Defense Services Not Otherwise Enumerated
Who legally enforces ITAR? The US Department of State Directorate of Defense Trade Controls (“DDTC”) interprets and enforces ITAR.
Who physically enforces ITAR? The US Department of Homeland Security enforces ITAR. Specifically, Special Agents under the Immigration and Customs Enforcement (“ICE”), along with US Customs and Border Protection Officers physically inspect imports and exports at US border crossings and international airports.
Registration. All manufacturers (as well as exporters and brokers) of defense articles are required to register with the State Department.
Satellites and their components. Prior to 1992, satellites components were considered munitions, subject to ITAR and enforcement by the State Department. However, during the mid-1990s, the US Commerce Department took on responsibility for regulating communications satellites, under the Export Administration Regulations (“EAR”).
Arms Export Control Act
Another major related law is the Arms Export Control Act (“AECA”). This law gives the US President the authority to control imports and exports of defense articles. It requires foreign governments receiving any weapons from the US to use them only in self-defense. The law also places certain restrictions on US arms traders and manufacturers. If they sell sensitive technologies to “trusted” parties, thorough documentation is required, and they are completely prohibited from selling those technologies to certain other parties.
Export Administration Regulations
One other significant set of requirements governing rocket launches and space activity is the Export Administration Regulations (“EAR”). These regulations govern whether something may be exported from the US, and whether it may be transferred from one person to another in a foreign country. The US Commerce Department administers these regulations.
Similar to the US Munitions List under ITAR, the EAR has its own Commerce Control List (CCL). This is a list of items that may have military use and not just commercial use. The vast majority of what’s covered under the EAR are just commercial exports and are not on the CCL.
What counts as an “export”? An export could be any of the following:
1.An actual shipment of an item outside the US;
2. Releasing or transferring technology (including source code) to a foreign person within the US;
3. Transferring registration, control, or ownership of spacecraft, in certain circumstances.
General Prohibitions. The EAR contains a list of 10 General Prohibitions. I won’t list them all in excruciating detail here, but basically there are certain things that are prohibited when it comes to exports, and they’re all more or less common sense. Unless you have a license or an exception applies, you cannot export anything to certain countries (e.g. North Korea, Iran, Syria, etc.), or to an end-user (or end-use) that is specifically prohibited. You can’t export things that are on the CCL (i.e., that have potential military use). You cannot perform certain activities that are related to nuclear explosives, missiles, chemical weapons, or biological weapons. You also cannot export things that even pass through a list of certain countries (e.g. North Korea again, Cambodia, Laos, Vietnam, and about a dozen others) without a license. Finally – you cannot violate the terms or conditions of a license, license exception, or any order issued under the EAR, and you also cannot export, transfer, forward, or do anything else with an item subject to the EAR with the knowledge that a violation of the EAR would occur.
Summary
These are just a few of the laws or regulations that govern the aerospace industry and space activities, but they are three of the biggest and most important to know about.
I recently finished reading an excellent biography about Wernher von Braun. While browsing a used bookstore in Victoria, BC last year, I picked this book up on a whim. I really didn’t know anything at all about the man or his life, prior to this. In retrospect, I cannot believe I didn’t know anything, and I have to say I’m absolutely floored.
The book is Von Braun: Dreamer of Space, Engineer of War, by Michael J. Neufeld.
Werner von Braun, the German-born American rocket engineer, with model rockets
The title really does a great job of summarizing the theme of the book. Von Braun’s life was in many ways a dichotomy between, on the one hand, his lofty intentions, a fascination with rockets and plans to use them for spaceflight and travel to the moon and distant worlds, and on the other hand, the darker side of his achievements, which were the creation of a weapon of immense destruction and war.
Pre-1945: German background and the Nazi regime
Von Braun straddled two worlds in many different ways, both literally and metaphorically. He was born and raised in Germany, received an education as an engineer and became an extremely effective and capable leader in engineering management – that is, leading large, complex engineering projects and organizations involving hundreds or even thousands of people.
As the Nazi regime came to power, von Braun was gradually pulled into its orbit (or intentionally gravitated towards it, depending on your view). He saw that the military and government were a powerful source of funding for the research and development of rockets, and von Braun seized the opportunity.
At Peenemunde, he developed rockets for the Nazi regime, including the infamous V-2, the world’s first long-range guided ballistic missile. The Germans used the V-2 during World War II to attack Allied cities, as retribution for Allied bombings of German cities (thus the German name for the rocket, Vergeltungswaffe 2, meaning “Retribution Weapon 2”). The V-2 was also the first rocket to travel outside the earth’s atmosphere into space. The rocket von Braun brought to fruition was therefore used to bring destruction during the war, but also for pioneering spaceflight, a familiar duality in von Braun’s life.
Von Braun joined the Nazi party and even met Hitler on several occasions. He rose in the party’s ranks and became an SS officer. And yet he never seemed particularly enthusiastic or dedicated to the Nazi ideology or cause. It was clear that his only passion was rocketry, and the Nazi regime was willing to pour vast amounts of money into his organization at Peenemunde. At the same time, he never seems to have strongly objected to what the Nazis were doing, although he likely wasn’t aware of the full horrors of the Holocaust at that time. Years (and decades) after the war ended, von Braun condemned the regime, but of course that was much easier to do in retrospect and seems opportunistic.
William Pickering, James Van Allen and Wernher Von Braun hold a model of Explorer 1 in triumph after the successful launch of a US satellite
Post-1945: Spaceflight program leadership in the United States
After World War II ended in 1945, von Braun emigrated to the United States, one of several dozen scientists brought over as part of “Operation Paperclip.” He settled with his wife in Huntsville, Alabama, and with many other German workers as part of his organization. Von Braun lived in Huntsville for the next twenty years, raising a family there, and working for the US Army. He played a lead role in developing the Redstone rocket, which was used for the first live nuclear ballistic missile tests for the US, as well as the Jupiter-C rocket, which launched the first US satellite, Explorer 1, in 1958 (although this was not the world’s first satellite, which was the USSR’s Sputnik 1, in 1957).
Von Braun may have been opportunistic, but he thoroughly embraced his new American identity and believed that the US should lead the “free world” in the space race against the Soviet Union.
He later joined the newly created NASA in 1960 and played a major role in historic NASA projects, including the Mercury Redstone, Gemini, and Apollo programs. He was dedicated to the success of the Apollo program, and under his leadership, Apollo had a flawless track record for safety and success. The Apollo 11 lunar landing – the achievement of seeing humans actually set foot on the moon in 1969 – was probably the highlight of his life.
von Braun standing in front of the engines of the Saturn V
This is of course only a summary of von Braun’s life, and in this summary I am doing him an enormous disservice. Beyond his engineering, technical, and management genius, von Braun also increasingly became a popular household name as he began appearing in Walt Disney-produced documentaries in the 1950s about the future of spaceflight, and man in space. These documentaries themselves are fascinating, in retrospect, and are the subject of an entire separate post I plan to write.
A controversial legacy
Von Braun was a lifelong spaceflight enthusiast and strongly advocated for putting humans into space and going to the moon. It is safe to say that he is one of the most important individuals of the twentieth century: he basically led the development of the liquid fuel rocket into a mature technology, and he was directly responsible for the success of NASA’s Apollo program, among other accomplishments. And yet his rockets also have the legacy of destruction. He is ultimately responsible for the development of intercontinental ballistic missiles (ICBMs) and the dangerous cloud of nuclear war that hung over the entire world for the latter half of the twentieth century, and continues to hang over us to this day.
Intriguingly, this is a man who was an SS officer in the Nazi party and built weapons for Adolf Hitler, and yet also joined the US government and obtained security clearances, rose in its ranks, and personally met with multiple presidents including Dwight Eisenhower, John F. Kennedy, and Lyndon Johnson.
I highly recommend this book for a thoughtful, balanced study of von Braun’s life in much more fascinating detail.
The epic fin-ale to the fin attachment series! (Pun intended.)
So far, we’ve attached the fins using the “through the wall” method with epoxy at several points: (1) the fin root, where it directly touches the motor mount tube, and (2) all along the inside edges of the fins and motor mount tube using a syringe to inject it. This created an incredibly strong foundation (especially by mixing some chopped carbon fiber into the epoxy), and at last we can turn to (3) the outside of the rocket to create fin fillets.
making tape to create lines
The first step here is to measure and mark approx. 3/8 inch from the joint, along both the airframe and the fin itself, and draw parallel lines on each. Then follow this up with masking tape along the full length of each line. Using this technique, you can apply the epoxy fillet, and when you remove the tape afterwards, it will leave a very clean edge. Generally you want to wait before removing the tape so the epoxy has a chance to partially cure – but it’s easiest to remove the tape if you do so before it fully cures.
aerodynamic and aesthetically pleasing
For the epoxy mixture, the difference this time will be the addition of a thickening agent so it’s not quite as runny and it maintains its shape. Specifically, this means first mixing the two part epoxy (resin and hardener), then mixing in some chopped carbon fiber as before, and finally adding the thickener.
As I mentioned earlier, I’m using West System resin and hardener, and also for the thickener. The stuff is extremely lightweight – so much that it’s almost difficult to even take the can’s lid on or off, as the slightest breeze or air movement will cause it to fly up into the air like dust. Of course, this is something that should be done only while wearing a respirator or face mask.
Once the epoxy is sufficiently thickened, it should have the consistency of peanut butter – spreadable, but will more or less hold its shape.
Finally, a round length of wood (e.g. a broomstick) or plastic (e.g. metal pipe or PVC pipe) will be very helpful at this stage, particularly one that has a 3/4″ or 1″ diameter. I happened to have some spare 3/4″ PVC pipe lying around from my earlier project running electrical wire to the shed to build the workshop. The idea here is to spread some epoxy on at the joint where each fin touches the rocket body, and then to use the PVC pipe to run along the full length, creating a nice, smooth, rounded fin fillet.
a first pass
Above is a picture showing my partial progress with this technique. It can take some practice getting the right epoxy consistency with the thickener, and also using the pipe to create the rounded fillet. But once finished, this will provide the third and final bond of the fins to the rocket body.
As noted above, you can wait before removing the masking tape, but don’t wait so long that the epoxy fully cures.
After one set of fins is complete, as shown above, you can rotate the rocket 120 degrees and repeat (although give the epoxy some time to cure, first, before rotating). Repeat a second time, and then rotate and repeat a third.
Once all the fin fillets are completed, you’re done with the actual rocket build! The rest is cosmetic work or just attaching things to this newly constructed rocket: priming and painting (which, frankly, is optional), attaching recovery harnesses and parachutes (slightly less optional but simple), and conducting ground testing.
Fair warning here: I’m actually splitting the “attaching the fins” information into three separate posts. This is not out of a sense of malice or sadism, but simply because there’s a lot going on with the fins.
The prior post (part 1 of 3 in this epic fin series) was basically the prep work and first few steps to secure the fins to the rocket body by using some epoxy and inserting the fin root through the wall where it can bond against the motor mount tube inside. Along with a printed fin alignment guide and a bunch of heavy objects, this keeps the fins in place and serves as a starting point for the multi-step approach for attaching them.
This post (part 2 of 3) involves epoxy, a syringe, and a bunch of strategically drilled holes. This might sound like the setup to a bad joke, but it’s actually literal and straightforward.
If you’ve been following along so far (whether with your actual fiberglass rocket build, or just conceptually in your head), you know that inside the airframe there is a motor mount tube, held in place and centered with the aptly-named centering rings. The top and bottom of each fin should just barely be touching a centering ring, inside.
ready to inject!
The idea here is to take the syringe and inject the epoxy into each hole. There’s two holes per fin (so 12 total in this case for 6 fins), with one hole on either side of each fin, roughly 1/2 inch away from the fin. Using a typical plastic syringe that you can find at a local drugstore, you can inject 10 ml at a time, and you should inject roughly 25 ml for each side of the rocket, split evenly among 4 holes. The rocket should be positioned horizontally and completely level, as in the above picture.
Once the epoxy has been injected into these 4 holes, you tilt the entire rocket forwards and then backwards, slowly, in order to move the epoxy around inside and completely coat the area where each fin touches the motor mount. The centering rings on each side should create a “dam” to prevent the epoxy from going any further past the edge of the fin, if everything is aligned reasonably well.
(If not, well, the epoxy may ooze out some of the other holes below a little. Not a huge deal, but may require a bit of extra cleanup.)
Once the epoxy is spread evenly inside, it needs some time to cure. Come back a few hours later. At this point, you can rotate the rocket 1/3 of the way around and repeat the process for the next 4 holes, and then finally a third time after that. Ensure each time that the rocket is level as the epoxy cures, so it doesn’t slowly ooze and collect in a lopsided fashion. This would not be ideal for a uniform fin attachment, it could also throw the rocket off balance in its weight.
two part epoxy mix
Above is a picture of the two part epoxy mix (resin and hardener) when combined and thoroughly stirred in a small plastic cup. The syringe I used is pictured as well. You may need several since they can get clogged over time.
One final note here: you can also mix some chopped carbon fiber (pictured below) with the epoxy, and again mix thoroughly. The color will darken noticeably. This epoxy mixed with chopped carbon fiber will significantly strengthen the bond as it cures. In other words, those fins are never coming off.
epoxy mixed with chopped carbon fiber
This epoxy injection technique is pretty cool, and it’s been tested and used successfully for many years. Try it!
In my next post (part 3 of 3 in this series on attaching fiberglass fins) I’ll briefly cover the final step: creating external fin fillets where each fin touches the rocket airframe. It gives one final layer of protection to ensure the fins are secured, and also looks more aerodynamic.
If you’ve never put together a rocket before, well, I’m baffled that you are reading this blog. But typically, a rocket will have either 3 or 4 fins, which are placed symmetrically – equally spaced out, in the 360 degrees around the center. If 3 fins, then they’d be 120 degrees apart; if 4 fins, then 90 degree spaces.
This rocket has 3, and then another 3 aligned above them for a total of 6, each spaced out by 120 degrees. I think having 6 in this arrangement is purely aesthetic, as opposed to just having 3. Who knows?
I’ve used this two part epoxy before (resin and hardener) in one or two previous steps with this rocket construction. But this is the first time I’m using it in larger quantities.
back that up
Basically, I used a fin alignment guide (which I found online for free and printed out) to ensure that the fins were aligned properly, spaced exactly 120 degrees apart all the way around. I then prepared some of the epoxy and applied it with a popsicle stick (sophisticated technology), applying it to the edges or “roots” of each fin as if I were buttering a piece of toast. I inserted each fin into its slot, where the fin edge or root with the epoxy is pressed up against the motor mount inside. This is the first of several steps to ensure the fins are securely attached, starting with the interior.
To hold everything in place while this initial round of epoxy cures, I had a couple options. I saw some fancier solutions that other people have done involving using jigsaws and drills to cut out holes in large plywood sheets, and lots of vises and clamps.
That seemed like a lot of work, so I just used some rubber bands and propped the rocket/ fins up against some heavy objects like cans of paint or bricks while it cured (making sure nothing could move, and that the fins were aligned perfectly according to the alignment guide).
For a closer look at the epoxy, I included this photo as well, since it’s critical to this and the next few steps. I used West System epoxy as it was highly recommended, and it works great. The 105 is the epoxy resin, and 205 is the hardener. Each comes with a pump, and you just combine one pump of each into a mixing cup, and mix thoroughly for several minutes. It begins to cure pretty quickly, and the chemical reaction causes it to get extremely hot as it cures (to the point where it will burn you if you touch it, even through the plastic mixing cup, and steam is visibly coming off the top).
mixing two-part epoxy
For most of the fin attachment points, I’m also mixing in some chopped carbon fiber (pictured here as well) which is, in certain places, injected inside with a syringe. The carbon fiber greatly strengthens the epoxy as it cures.
Next, I’ll continue using the epoxy to attach the fins via this injection method, along the inside. After that, a final application of carbon fiber-infused epoxy on the outside of the rocket to create fillets (i.e., just a narrow strip of epoxy along each area where the fin touches the outer rocket body, shaped into a curve to minimize drag).
Things are really coming along – with the fins finally attached, it’s starting to look like a rocket!
Before I jump into the riveting details of rail buttons, I’ll take a step back and explain what this is, and why it matters.
Every rocket has a “center of pressure” and a “center of gravity” (or center of mass). I won’t go into detail about these concepts here, but basically, the relationship between these two things is important for a rocket to remain stable in the air. When it’s moving at a fast speed, the fins help keep it going in a straight line (i.e., up) because of the way the air pushes on them. I’m oversimplifying these concepts, but this is the point:
When the rocket is sitting on the launch pad and first lifts off, it is not moving quickly enough to be stable. If you tried launching a rocket from a pad without any kind of support, there would be a pretty good chance that it would not ascend perfectly vertically. It’s entirely possible it would not ascend at all, as it might tip over and fly horizontally (perhaps into a crowd of spectators). This is not ideal for your rocket, or for the spectators.
The solution to this is to provide just enough support for the rocket to keep going vertically as soon as it launches and just begins to (quickly) gain speed. With small model rockets, a thin metal pole is all you need, just a couple of feet high. The rocket will have a small launch lug (basically like a plastic straw) attached to its side, which slides down over the metal pole, ensuring the rocket takes off using the pole as a guide.
For larger rockets, it’s the same concept but with slightly fancier hardware. Instead of a thin pole, the launch pad will have a much bigger rail standing vertically for support. And instead of a plastic straw glued to the rocket, it will have rail buttons, made from plastic and secured by drilling a hole in the rocket body and attaching with metal screws.
the parts
The concept is extremely simple, and installation is fairly simple as well. It just requires measuring where you want the two rail buttons to be located, marking the spots, and drilling to insert the hardware. In general, you want the rail buttons exactly halfway between two fins, with one very close to the bottom (aft) end of the rocket, and another some distance up the side.
the finish
Often one or both is drilled and screwed directly into a centering ring. Whether that’s possible or not on your particular rocket, it also helps to add a small amount of epoxy just to make sure it’s secured in place. Here, you can see where I attached the rail buttons on this fiberglass rocket.
the alignment
And that’s it! Rail buttons installed, and the rocket can be flown from a standard launch rail.
The next step will require slightly more work: attaching the fins, which are of critical importance in achieving that fashionable “rocket” appearance.
After a delay of several days due to weather conditions, NASA and SpaceX made history today with a successful launch of the Crew Dragon vehicle atop the Falcon 9 rocket.
The launch took place at 3:23pm eastern time (12:23pm out here on the west coast). The two astronauts aboard the vehicle, Bob Behnken and Doug Hurley, are now well on their 19 hour journey to dock with the International Space Station, where another US astronaut and two Russian cosmonauts await their arrival.
This is a historic mission – the first time the US government is launching a manned rocket from US soil since the final Space Shuttle flight in 2011. It’s part of a new public-private partnership called the Commercial Crew program, a joint effort between NASA and SpaceX.
On top of this, after the Falcon 9 detached from the Dragon vehicle, the rocket had a successful vertical landing back on earth.
Improbable Ventures 