Akin's Laws of Spacecraft Design
spacecraft.ssl.umd.edu
spacecraft.ssl.umd.edu
> #20 A bad design with a good presentation is doomed
> eventually. A good design with a bad presentation
> is doomed immediately.
It's an amenity, though.
There are quite a lot of items on this list that applies to any kind of project management, software development.
This is too close to home, will enjoy responsibly.
I guess one aspect why "agile" stuff is effective, is that the "last day" (on which it becomes surprisingly easy to make all the decisions that couldn't be made until now) happens multiple times and earlier in the project.
Sources: - SLS - Orion - James Webb Telescope - constellation/Ares V project
At least, that's what I assume, since I've heard this sentiment expressed in the much clearer phrasing "If you haven't got the time to do it right, when will you find the time to do it over?".
That's apparently the title of a popular book by a management consultant named John Wooden, but I'm not sure of the provenance of the quote.
Being the one learning through failure in an organisation not tolerating it isn’t fun.
Including "maiden flight with astronauts".
Several test pilots, and astronauts died and we still went to air/space.
Requiring no risk of failure for people is a large part of why we don’t launch astronauts much.
Space is risky. Setting the expectation that astronauts can never be lost, as opposed to that they are on an exciting frontier that has its dangers, is out of line with astronauts’ own risk preferences. This has been a failure of expectations setting by NASA.
Practically grounding astronauts for three decades is not much better.
This one probably the best:
36:Any run-of-the-mill engineer can design something which is elegant. A good engineer designs systems to be efficient. A great engineer designs them to be effective.
This statement reminded me of the popular quote on teacher, “The mediocre teacher tells. The good teacher explains. The superior teacher demonstrates. The great teacher inspires.”
I don't think you will find this in any dictionary, but the meaning is incredibly consistent, even on different engineering areas and different languages.
Mediocre: pick one. Adequate: pick two. Outstanding: pick three. And customers are happy too.
Of course, only really feasible for 1-1 teaching.
"39. (alternate formulation) The three keys to keeping a new human space program affordable and on schedule: 1) No new launch vehicles. 2) No new launch vehicles. 3) Whatever you do, don't develop any new launch vehicles."
edit: If we count back to the first successful propulsive landing, the technology was only 5 years old. Falcon Heavy had been planned since way back in 2005.
The central tank is kind of like Shuttle’s, to justify building it in the same factory in Louisiana, but it’s a different diameter, so it had to be a clean-sheet design and all of the tooling had to be created from scratch. The solid rocket boosters are similar to Shuttle (the good Senator from Utah, with all his engineering expertise, required SLS to use solid fuel boosters that only one company in Utah can make), but a different number of segments in length, requiring them to be designed from scratch.
Early in the process of SLS (under its original name, Ares V), a group of NASA engineers lobbied for a true Shuttle-derived version, which would have been much cheaper and quicker to create, with the benefit of lots of flight heritage. Of course they got nowhere, because none of that was why SLS was the way it was. Everything about SLS is designed for the sole purpose of funneling the maximum amount of money to the right contractors in the right states for as long as possible. Thus, it is acceptable that it has never flown even after so many years and so many billions—indeed it’s desirable! If the costly design phase goes on for as long as possible, the money spigot will dispense much more than if it proceeded into operations.
But, just in case, SLS will undergo two costly redesigns after coming into service: a whole new upper stage and new boosters. That should keep the gravy train running for a good long while.
In addition to the Shuttle-industrial complex which must be kept running with make-work, there is now a Station-industrial complex which must receive the same treatment, in the form of an utterly useless lunar-orbit station called Gateway. I’m not sure if you can tell but I’m fairly bitter about all this.
DC-X: First flight (and first successful propulsive landing) 18 August 1993
https://en.wikipedia.org/wiki/McDonnell_Douglas_DC-X
"In December 2015, a Falcon 9 accomplished a propulsive vertical landing."
https://en.wikipedia.org/wiki/SpaceX
See also:
https://en.wikipedia.org/wiki/VTVL
Not mentioned in the above link was an amateur group developing VTVL tech around the San Francisco bay area in the 90's. IIRC, it was EPRS. FWIW, they also invented a multi-rotor platform to test their conrol system that evolved into the modern drone.
However, #39 doesn't say “don't ever develop new launch vehicles”, rather “don't develop new launch vehicles if staying in budget and on timeline is your priority”.
And developing their crewed launches has been over a billion dollars cheaper than Boeing, and successfully launched years earlier.
Starship, however, is in fact designed for humans. But it is not part of a "human space program", rather it is a multi-purpose vehicle. It is yet to be seen towards which human space programs it will be applied, but even with the Artemis bid many aspects of Starship were clearly designed without the Artemis bid as a specific target.
What has likely changed is that there is sufficient demand for cargo flights to bootstrap an affordable human flight program on top of it.
I wish I'd learned this a long while ago. Going on some of my current projects, it seems that a good portion of my brain still hasn't!
That’s interesting. I generally have strong opinions about things I care about and would much rather be the one making decisions so I can own the outcome, ESPECIALLY negative outcomes. Maybe it’s just a control thing... I’d rather fix my own mess
This has largely been my experience.
Are they in it for the title or the prestige? Their desire will as some point run in conflict with the larger program goals.
Do they do it because they enjoy bringing a diverse set of viewpoints together to create something that couldn't be created in isolation? That might have a better chance of success.
Unfortunately it's very difficult to determine this externally without a significant investment in time or otherwise.
That reminds me of the phrase:
If you want to go fast go alone. If you want to go far go together.
Is it contentious to say we're going through a point in time where this is not commonly held?
What I really want to figure out is am I mis-remembering or were the late 90s / early 00s pretty strongly centre biased?
It's not clear that this is a good rule. If you want to get mass from ground to orbit, the rocket equation means that you want the least quantity of infrastructure mass that will work, maximizing the payload fraction. If you're in charge of safety equipment on an orbital station, you want the most effective things you can cram in to your mass budget.
Life support? Whenever possible, eliminate it in favor of automation. But if you need it, you either want minimal (emergency only) or maximal (resilient against disasters) to the extent of your available space/power/mass.
https://en.wikipedia.org/wiki/Argument_to_moderation
Particularly as “the middle” can be dependent on where the ends are. The middle ground of American politics is different to the middle ground of European or Chinese politics for example.
Such an amazing place to be.
https://www.centauri-dreams.org/2006/11/24/barnards-star-and...
See also, #1 and #12 that should be considered in your example too.
I’m guessing it’s because of the need to go through our atmosphere first.
Wouldn’t an omnidirectional saucer-like shape (or spherical for larger ships) be more practical in 3D vacuum?
Because they have directional main engines. That does not strictly necessitate them to be pointy on the opposite end, but it at least requires some design that can distribute the force through the ship's body with the minimal amount of structural mass. E.g. an axial design that only has to withstand compressive forces, not shear forces.
A bigger issue is the lack surface area for cooling. Not even The Expanse gets that one right.
Care to elaborate? What's "lack surface area" and how does the Expanse get it wrong?
This question is not 'Expanse'-related but inspired by David Brin's 'Sundiver'.
The last option techie that I've ever heard for rejecting heat already onboard on a spaceship (and this is pure technobabble from proposals about Star Wars ships massive power generation needs) would be some magical way to convert heat into neutrinos, which, since neutrinos can pass though most matter, could be inside the ship and still function as a heat rejection mechanism. [2]
[1] https://www.laserfocusworld.com/lasers-sources/article/16547...
https://toughsf.blogspot.com/2019/10/the-expanses-epstein-dr...
The author suggests creating a fusion reaction well behind the ship, but channeling the useful parts of it in an electromagnetic field tunnel to create thrust while dissipating the heat more effectively. Vaguely like Project Orion, but with a more-or-less continuous external fusion reaction instead of a series of nuclear explosions. I am not a physicist, but they seem to have done their homework.
You need 3-10 m^2 of radiators for every kW of power you use. If your ship is powered (I mean internal power, not engine exhaust) by a 1MW reactor, then you need radiators close to the scale of a football field pushing out waste heat, no matter what tech that reactor uses.
https://www.wolframalpha.com/input/?i=1+kW%2F%28Stefan-Boltz...
Based on that, you need 3-10 m^2 of radiative surface area per kilowatt, but that's assuming your equilibrium temperature is 203 to 275 K (-70 to 2 °C). Assuming I haven't made some basic mistake, couldn't you decide to heat part of your surface to some much higher temperature and radiate most of your internal power out of that part?
Of course, you could have a heat pump pushing heat to a higher temperature surface, some current radiators do that, but it has its limitations requires more energy for the pump the higher temperature difference you want to sustain.
This depends on the working temperature of the radiator too. In theory if area needed to be optimized a (series of) heat pumps could shed more power from a hotter radiator.
If future designers want to be cute about it they could stick a high temperature radiator at the front of the ship as a headlight and lower temperature radiators in the back for a tail light.
As for the real world: there are plenty designs that are not pointy and flying: every satellite, the ISS, the lunar lander... however, all the designs that interact with earth's atmosphere have to respect aerodynamics. Thus, just about every ascent vehicle becomes pointy. Landers are different. The Soyuz return module doesn't look particularly pointy, for instance.
* There would often be a need to separate human areas from more energy rich areas. A pointed solution often allows for this separation.
* Current engine design has a "rear end" of some sort, which then implies "pointing"
1. You can look back on projects you’ve done or projects you’re working on and try to see how they fit with your work.
2. Trim the list down and add the remaining items to a list or documented ordered by what you work on. Keep the remaining items in a handy place you can reference when you’re in appropriate steps of your project.
For example, the rules in the article can possibly be grouped as follows: 1. Project timelines, 2. project accountabilities, 3. Engineering requirements and design. I would then refer to these in the corresponding phase of a project.
It would be nice if there was a store attached to each law. Knowing the source of the law would be helpful in knowing how to apply it.
Yes, sexist, I know. I recall this from many years ago but have not been able to find an official source. Anyone know?
With or without numbers, it's still an opinion?
Numbers that come from measurements are often not precise enough, measure additional things, massaged until they fit the preconceived etc. So its still the opinion pretending to be engineering.