Spacecraft a Week

Some of you know that I’m a longtime fan of Jonathan Coulton.  Great songs on a variety of topics, including space.  At one point he gave up his job as a software engineer and set himself the goal of writing and recording a song a week.  That year-long effort provided the basis for several of his albums and live shows for what is now close to a decade.

I have no plans to leave Cornell and hit the road with my guitar.  However, I am going to design a new spacecraft every week. Then I’ll blog about it.  You can read them at

One reason for my doing so is a conversation I had with a former chief technology officer for a large government agency. No, not NASA. A different one. He asserted that his time at the agency had already addressed the remaining open problems in space technology, that there was nothing fundamentally new to be done. Only incrementalism remained. We agreed to disagree.

Another has to do with the two years I recently spent at NASA. I served as the agency’s Chief Technologist. From time to time I would encounter a similarly dreary perspective among some members of the world’s space community. But, as I had hoped, I also found the opposite. There is a lot of enthusiasm out there for innovating in space. Many of us believe that the best days are ahead, that there are inventions to make, adventures to experience, and science to discover. NewSpace companies are popping up all over California. Some have their sights set on asteroids, mining them to create a self-sustaining space economy and space infrastructure, and some are going to image the Earth in unprecedented temporal and spatial detail. Some of my academic colleagues are setting out to explore space on their own: discovering new planets, understanding the Earth, and maybe heading to Mars in the next few years, all without waiting for the science community to catch up.

I offered some additional thoughts on this topic in the first post. Let me emphasize one in particular here.  There is simply not enough money available for research on these topics to allow my group to pursue every idea (good or otherwise) that we come up with.  That’s true even if mine were the only ideas we tried to work out, but students come up with great stuff too.  So, rather than let them spend the next few decades mouldering in the back of a old notebook on a shelf, or scribbled on a piece of paper in the stack of unfinished business on my desk, or listed in an Excel spreadsheet that will eventually become obsolete and unreadable, I thought I’d just put them out there.

This week I was reminded again how out-of-sorts people can become if they feel the haven’t got enough credit for their work, whether or not desired credit is in proportion to what they contributed.  SSDS’s projects include the contributions of many people, some of whom go unnamed. I hope that the most influential are acknowledged on the website somewhere or in our publications, as appropriate.  As an example, our early work on Lorentz Augmented Orbits was conducted with the help of dozens of undergrads and master’s students, several Ph.D. students, after many conversations with colleagues all over the U.S. domain name values and in the U.K., and with the sponsorship of several government agencies whose program managers and contracts people all had a part to play.  It’s just not feasible to cite every little contribution every time someone asks about a project.  In my experience, there tend to be only one or two people who really bring the projects to life, and I tend to give them the credit when I talk about the projects to others.  I think that’s OK.  For instance, Brett Streetman and Justin Atchison are the two former SSDS members whose work I cite when I’m talking about LAOs.  My doing so should not imply that everyone else’s work is of no value or that their participation is being intentionally, conspiratorily purged from the record.

So, I’ll try to give credit for innovations I’m aware of.  If I neglect to mention someone with whom I talked about these spacecraft already, or who affected my thinking on a subject years ago, however slightly, I sincerely apologize.

Equations and Spheres

As I mentioned last week, some of the resources we can utilize in space are orbital dynamics themselves.

The Clohessy-Wiltshire equations describe how a small ‘chaser’ spacecraft will behave in the reference frame of a larger target in a near-circular orbit. Fortunately, these conditions do a good job describing a small inspection satellite crawling the surface of the ISS. The equations describe the chaser’s dynamics in the reference frame fixed to the target’s center of mass.

The Clohessy-Wiltshire equations are traditionally written in Cartesian Coordinates:

    \[\ddot{r}_x = 3n^2x+2n\dot{y}\]

    \[\ddot{r}_y = -2n\dot{x}\]

    \[\ddot{r}_z = -n^2z\]

Where n is a constant of the target’s circular orbit \sqrt{\frac{\mu}{R^3}}

Is it possible for this chaser to ‘stick’ to the target? Yes, if you’re in the right place. The CW equations are not new, so one would expect this question to have a well-established answer. However, without a contactless actuator allowing the chaser to safely maneuver close to the target, you didn’t want satellites anywhere near each other, let alone ‘sticking’ to one another. web search history Where does this relative attractive acceleration occur? Wherever the radial component of the relative acceleration is negative – that is, orbital mechanics cause the chaser to accelerate towards the target.
The radial component of acceleration in spherical coordinates is complex if the chaser is moving in the target frame (that is, \dot{x},\dot{y} \neq 0. However, if the radial acceleration of a stationary chaser on the surface of a spherical target of radius r is

    \[\ddot{\rho} = n^2 r\left( 3 \sin^2{\theta}\cos^2{\phi}-\cos^2{\theta} \right)\]

This leads to the condition that if 3\tan^2{\theta}\cos^2{\phi} \leq 1 a stationary chaser will constantly accelerate towards the target.

Where does this acceleration occur? Darker blue areas on this plot show negative/inward radial accelerations.

acceleration surface

This initial exploration leaves a lot of unanswered questions: What happens when these forces are mapped onto the surface of a real target like the ISS? Is it possible for an inspection satellite to take advantage relative velocity to safely enter the red ‘repulsive’ zones? If so, what would those trajectories look like?

Massless Exploration


NASA’s various technology programs are investing in a wide range of additive-manufacturing technologies. Some focus on the terrtestrial problem of how to manufacture aerospace parts. Others focus on the NASA-unique problem of how to fabricate hardware in space. It’s not just NASA-unique. It’s also revolutionary. If done right, these technologies may revolutionize space science and human exploration.  The image above is from Deep Space Industries.  It’s a concept in which a sort of 3D Printer sucks mass out of an asteroid and prints it into a deep-space habitat.  That would be revolutionary, no doubt about it.

Here’s where we could start. In 2012 the National Research Council identified the top technology-development priority for NASA: improving access to space. (“NASA’s Space Technology Roadmaps and Priorities” (2012) ). So, late last year Air Force Space Command and NASA partnered to sponsor a study with the following goals:

1) Lower the cost of space research and exploration in the long term through targeted, sustained investments that start immediately.
2) Identify new space-system architectures that can be realized only if in-situ manufacturing is possible.

For this first goal, even with a new generation of lower-priced launch vehicles, e.g. from SpaceX, the economics of space will continue to deter most commercial and government organizations from using space for the nation’s scientific and economic benefit. Unless someone creates a killer app to kickstart commercial use of space, we will need a paradigm shift. That new paradigm is what I’m calling “massless exploration:” change the ratio of mass launched from earth to mass used in space. In the limit, the mass we use in space all comes from space. So, we would be exploring space without mass from Earth, i.e., masslessly–at least from the launch perspective. But you see that this perspective gets around the access-to-space barrier, if it could be made real.

As for the second objective, imagine if we could fabricate in space all the spacecraft components, structures and instruments for human exploration, and expendables (such as propellant, food, and oxygen) to support those efforts.
In such a future, what would space-system architectures look like? What would we be fabricating if we had the means to do so? Spacecraft, habitats, even human-specific operations would likely look very different and be composed of unfamiliar materials.  And for the U.S. to realize such architectures, what are the advanced-manufacturing technologies we must develop now?  That’s the real question, in my opinion.

Massless Exploration provides a purpose, a direction for what are at best uncoordinated technology-development activities in additive manufacturing.  At worst, some of them are duplicative or poorly motivated.  We need a substantive roadmap that takes us from where we are now–3D printed plastic–to space-systems architectures conceived in a way that is consistent with an in-orbit manufacturing capability.

So, let me try to state it again succinctly.  Massless Exploration is the NASA and AIr Force working title for the paradigm that answers this unique question:

“What science and exploration architectures are made possible by in-situ fabrication and assembly of space systems, whether from new raw material brought from earth, unused components already in orbit, or in-situ material, and what advances in additive-manufacturing technologies much be achieved in order to lower the ratio of mass launched from Earth to mass used in space?”

As we learn to reuse and extract resources from the space environment, we may be able to increase this ratio to the point where access to space is no longer the driver for the size, weight, and power of spacecraft.  At that point, we may be launching only humans and the particularly hard-to-manufacture components, such as integrated circuits and exquisite components for scientific instruments.  I joked about this idea in a Reddit AMA I did a few months ago, and the humor associated with manufacturing humans went right on past most folks.  It would be an interesting science-fiction story, though, printing up humans. Or maybe it’s too real to be funny.  But I digress.

NASA’s current portfolio needs a coordinated vision to establish an Agency-wide path to the future.  It needs connectivity to other activities at the agency and elsewhere at a strategic level.  If the NRC points the way, it is my hope that NASA and the Air Force will take on the much harder problem of developing science- and exploration-unique capabilities that will end NASA’s, and the nation’s, dependence on high-cost space launch. In doing so, I expect that transformational new technologies will spin off to the benefit of sectors of the economy beyond aerospace.

In this time of declining budgets for technology research, NASA must focus and synergize its technology investment dollars on high-priority areas that produce fundamental and required capabilities that NASA cannot acquire through other means. NASA cannot justify investing resources in capabilities already being advanced by others.  That need for focus is what motivates this study.


This image shows just a few of the ingredients of Massless Exploration that are already being brought together.  Whether it’s painting lunar habitats into existence with a sort of toothpaste-like lunar-regolith cement or simply fabricating CubeSat components with the goal of doing so in orbit, there is a wide range of applications and solutions.  I’m not alone in thinking about this problem.

I believe that the Maker Community has a big role to play here.  As I said in my previous post, we’ve reached a point in history where an individual can hope to build and launch his or her own spacecraft.  The impulse to make space, or make space work for us, informs Massless Exploration as well, through business-development incentives as well as simply the desire for adventure.  In my opinion, the role of government is to establish and nurture these grand visions for the sake of the nation’s citizens and businesses.  If the right policies are in place, if we can consider space more of a national park (a “land of many uses”) than a sacred shrine, an object of mere detached scientific study, or the military high ground, we’ll see Massless Exploration all the sooner.

Like a Fly on the Ceiling

I realized recently that space engineers have to ask two big questions that don’t bother our ground-based counterparts nearly as much. “What happens when the computer turns off?” and “How do we create a system that won’t result in utter disaster if it does?”

There are two big thorns that prevent you from just wrapping a control loop around the system and calling it solved:

In space, a body in motion really does stay in motion. On earth, there are lovely things like drag and friction that put a cap on the motion of an uncontrolled system.

In space, the computer turning off is a far more likely event. Between power loss, radiation damage and glitches computers have to jump many hurdles in space. The inability of an IT guy to pop in and troubleshoot from a linux CD doesn’t help.

The flip-side to the ways space makes our job harder is that the same environment also provides many more ways to take advantage of natural phenomena. The rigid body dynamics of satellites that would otherwise be damped out or hard to model can be used to keep water flowing to an electrolysis mesh without pumps. Electromagnetic forces that would otherwise be overwhelmed by gravity and friction can actuate a spacecraft.

And just the other day, a back-of-the-envelope (ok a few sheets of paper) calculation confirmed that the difference in Earth’s gravity across a large satellite like the ISS is enough to ‘pull’ a small spacecraft towards its surface. It’s totally counterintuitive because this would happen on the *bottom* of the ISS. To take advantage of this gravitational ‘pull’ the small satellite would need a way to push back and drag itself parallel to the surface. Luckily, there may be a way to do just that …

Lunar Regatta

I’m gone from NASA only a month, and already they’re doing better without me.  It looks like NASA may kick off a new prize competition, their first space prize to involve actual spaceflight!  It may seem surprising that it has not happened before; after all, the X Prize Foundation and NASA’s own Centennial Challenges Program are already in their second decades of existence.  But, it is now happening.

I want to ask for your help, for the sake of the space technology community.  It’s very important for NASA to hear from us—some of the folks who may in fact compete for this $5M purse–that the prize is worth offering.  Please respond to NASA’s Request for Information and express your enthusiasm and commitment.  Here’s the URL:  If you agree that this approach incentivizes the development of technologies that will transform space exploration, say so.  Ask your colleagues to do the same.

That’s not hyperbole.  This competition would send an fleet of CubeSats past the moon, with prizes going to the best-propelled and the best communicating ones.  Call it a lunar regatta, maybe, or the first exhibition of space barnstorming.  I think you’ll agree that propulsion and communications are likely the greatest barriers to interplanetary CubeSats.  If we eliminate those barriers, we’ll open up the solar system to university research, citizen science, and even commercial development in a far more democratic way than is currently the case.  Democratization of access to the solar system is what’s ultimately at stake here.  And it’s going to happen, if NASA recognizes that such a competition will attract enough interest to advance the technology.

I plan to offer critiques of my own, but I’ll still encourage them to hold the competition.  For example, the proposed requirement to include a 1U science payload is a poor idea, in my opinion, for many reasons.  One is that it prevents teams from using that payload space to help fund their enterprises, by whatever means they may choose.  The Google Lunar X Prize made a similar mistake by keeping the media rights of the competitors.  Maybe worse is the risk that the science expectations will drive the engineering toward conservative solutions.  I say give the competitors minimal requirements, with as simple and elegant a competition as possible, and let innovation happen in its purest form.

But whatever your preferences, express interest in the prize, and encourage your colleagues to do the same.  This is going to be great!

The Journey of Data

A shrewd observer once noted: “The difference between science and entertainment is that when you blow something up, in science you take data.” It might seem trite, but the complexity of simply acquiring usable measurements about the real world is incredible and often glossed over (even by the engineers and scientists doing the gathering.)

We’ve come a long way since Galileo timed falling objects by singing to himself.

Take the state of the cart moving on the 1D air track. On the surface it would seem pretty trivial to measure it, but I’ve learned there is far more lurking below if you want fast and accurate data.

First, a stream of infrared light shines at the moving cart. It bounces off of the cart and from the phase difference between the outgoing and incoming wave, a tiny chip on the sensor sends out a calibrated voltage signal. At the same time, on the cart, a MEMS device vibrates a crystal that causes a voltage difference that changes based on its acceleration. Another chip detects, calibrates and amplifies this voltage. (MEMS stands for MicroElectroMechanical Sensor – say that ten times fast.)

Both of these continuous voltage signals are applied across the terminals of a connector box and are transmitted to a DAQ (data acquisition) card attached to the motherboard of a computer. The DAQ card converts the analog signal (actual voltage differences) to a digital signal – the ones and zeros that are useful to the computer and transmits them to the program running on the computer.

Cool! We’ve acquired the data…right? Not so fast. While the computer now nominally knows what the voltage differences across the SCB terminals, that doesn’t mean it knows exactly when each data point was measured. To guarantee that we know when those voltages happened is tricky, because most modern operating systems don’t make guarantees of accurate timing below 0.005 seconds or so. Since we want a measurement every 0.00025 seconds, the computer is running a special operating system that does nothing but acquire data and run calculations with it, guaranteeing our timing.

Finally, the real time program (having been calibrated earlier) converts the voltages into the actual units of interest, like meters.  Now, after all of that, the analysis and conclusions everybody actually cares about can happen. Whew. It’s hard to make an event science instead of just entertainment.

Thank you and hello

I’ve spent the last 2.2 years, or so, as NASA’s Chief Technologist. I’m now just getting back to Cornell, with all the freedoms and constraints that brings. Probably more of the former than the latter.

Let me share with you the last email message I sent to the NASA leadership and several other key people at the agency:

From: Peck, Mason A. (HQ-AA000)[NASA IPA]
Sent: Thursday, January 16, 2014 12:21 PM
Subject: Thank you and farewell

As you know, my time at NASA is over, and I’m at HQ at the moment helping in the transition to a new Chief Technologist. Let me take this opportunity to say that I am so grateful, and so honored, to have had the privilege to work with every one of you for the past two years. And thank you for giving this space geek a shot at offering some ideas about technology and ways to broaden its impact.

NASA continues to change the world, to inspire all of us, and being part of the team that does so was an extraordinary experience. Most of all, I appreciate the integrity and ability of NASA folks to set aside politics and pettiness for the sake of achieving something lasting and great. Doing so despite the pressures of a horrific budget environment is a reminder that NASA’s goals bring out the best in people.

I’ll be returning to Cornell University to undertake some new research and a few other non-academic projects. In fact, I’ll be teaching a graduate course this spring in spacecraft attitude dynamics and control. Feel free to drop by, sit in, and bring a very large coffee—we’ll see if I remember anything about tensor algebra after a couple of years’ worth of CJs and SPGs.

You can always find me at Please keep in touch.

There’s a lot to say about my time at NASA, including the fact that working on the inside of such an organization, especially among the leadership, illuminates the dark coreners and resolves mysteries in a way that I will find valuable for years to come.

I have a much better sense of why things get done really well and how things get bogged down. But I just have to say–for less than half a percent of the federal budget, NASA does an awesome job. It does so despite politically motivated critiques along the lines of “NASA has no plan, no mission.” All this comes from a cynical, and factually incorrect, place. I may go into detail more in a future post, but let me leave you with this: NASA has a clear plan for the future–humans to an asteroid in a decade, and humans to mars in the decade that follows. That’s pretty clear!

One issue that both hurts and helps the agency is that it does so much. It does aeronautics, science, and human space. It operates missions, conducts science, and does technology development. It’s also got one of the largest educational offices among federal agencies. I suppose that breadth and depth just confuses some people. And others use it as evidence that NASA lacks focus. But I can tell you that there is extraordinary focus. Intentionality. A sense of purpose. When you hear the political talking points to the contrary, just ask someone from NASA. They’ll be able to go on for hours about the awesome work underway right now. It’s work that will change our world and discover new ones. And it’s work that is becoming more inclusive–bringing in the commercial perspective (as opposed to the classical, bureaucracy-heavy approaches of the past) and bringing in individuals, citizen scientists and technologists.

On that point, here’s a selection from the second-to-last big message I sent out, one that I directed at the members of my (former) staff in the Office of the Chief Technologist at NASA Headquarters:

From: Peck, Mason A. (HQ-AA000)[NASA IPA] []
Sent: Thursday, December 19, 2013 11:32 AM
To:; CCTs (Updated) NASA CTC Distro List
Subject: End-of-Year Notes for the Office of the Chief Technologist

Making Space

Let me offer some end-of-year observations for the extraordinary people in the Office of the Chief Technologist. In 2013 OCT helped change the world. We innovated better ways for NASA to transfer its technology to American businesses. We established a new and profoundly transformative Grand Challenge, which has turned the nation’s attention toward protecting the Earth from asteroid impacts. We completed the agency’s first technology roadmapping process in many years with the release of the Strategic Space Technology Investment Plan, and we took the first steps toward a national policy for space-technology prioritization. We infused a prize-competition paradigm broadly across NASA to enable new kinds of public-private partnerships. And we spun off the Space Technology Program into its own mission directorate, giving it the level of visibility it deserves.

I want to thank each of you in the Office for the innovations that have enabled NASA to accomplish its mission and the extraordinary impact you have had in bringing air and space down to earth, to the public. I have referred to this process of democratizing space—access to space, space science, and space technology—as “making space,” a reference to the Maker community, where we have found an opportunity to encourage the growth of a self-sustaining economy of space.

Despite a difficult budgetary and political environment, you’ve all done outstanding work, whether through your advocacy at your respective centers through the Center Chief Technologists or through leadership at headquarters. Your efforts emphasize collaboration, consensus, and coordination, and that inclusive focus has led to considerable success in establishing a long-term vision for NASA’s technology with the broad participation of the agency’s technology community.

As my time at NASA comes to an end, I want to recognize that our office’s success is thanks to all of you: your hard work, your professionalism, and your passion for embracing change and reaching out across the agency to bring the best of NASA to bear on the agency’s strategic goals. I believe that 2014 will bring even more successes, including [a bunch of items that I will leave out of this blog post because they're too wonky].

I wish you all the best and hope you have a wonderful holiday!


So, I say “thank you and farewell” to NASA, and hello to Cornell. It’s great to be back, and I’m going to have a lot of fun.

Documentation Dilemma

A big goal of university research is to add to ‘knowledge.’ Engineers are always worrying about optimization, and how to add to the knowledge base is no exception. Specifically, there’s the tradeoff between a useful end result and making the steps to get there useful on their own.

On one end of the spectrum is the trap of ‘ta da! It works, but I can’t tell you how – no secrecy, I just literally don’t remember.’ On the other end is ‘well, I painfully documented every step I took. But that took so long I never actually got anything done.’

This tradeoff is embedded everywhere from the code you write (a quick and dirty script that gets the job done and never leaves your local machine to a beautifully documented bunch of source code on Github) to the programs you use – a format that’s less accessible (like Matlab), vs. a less efficient open-source (like python libraries) or less versatile, but commonly used program like MS Word. Hardware isn’t exempt either: an experimental setup could contain a few hundred dollars of off-the-internet parts or ten thousand dollars worth of custom components.

It’s a fine line to walk, and the correct balance varies by person and lab. In SSDS we mostly use Matlab, which is quite expensive for non-academic users, but try to document it well so that if someone was very interested, they could probably port it to something like SciPy. On the hardware side, I’m quite proud of our accessibility: you could probably replicate most of our setups with a few hundred dollars, the internet, a mill, a soldering iron, and some elbow grease.

Why focus on this intermediate accessibility? I think that DIY science, which faded during the early 20th century, is experiencing a resurgence driven by the Internet and both the open source and Maker movements. It’s just a hunch, but if university research can slot into this trend, everybody will win.

An easily replicable microgragravity simulator

An easily replicable microgragravity simulator

Math + Computers

Writing math with pen and paper is a pleasure. The symbols flow in just the right way. Unfortunately, you can’t just scan my handwritten notes and stick them in the middle of a conference paper. It’s so easy to forget what a pain it is to do math on a computer until I start writing up my results.

You would think that after more than a quarter century as a technical tool, computers would have an easy, or at least standard, way to input math. Just off the top of my head, I can think of at least four different ways, none of which plays particularly well with the others.

I thought I would share a list of the options (that I know of) to let you know what’s out there and solicit your thoughts on why one of these may be far superior (or the list is incomplete.)

  • LaTeX – the fabled granddaddy of keyboard math. Like all extremely versatile tools, it has a steep learning curve. You can get it to do everything, but it takes a lot of effort to get it to do anything. Additionally, it’s basically a programming language, so you don’t actually see the math as you’re writing. Unfortunately, the people who would be best at making math on a computer easier have been doing LaTeX so long they don’t understand why the rest of us can’t see the clear derivative of angular velocity in a green text on black background rendering of \dot{\omega}} It’s also terrible for collaborative editing.
  • Microsoft Word – basically the opposite of LaTeX in every way. What you see is what you get (WYSIWYG), and until recently, you couldn’t even enter equations via the keyboard. The collaborative editing is excellent and the equation editor has gotten much better. However, the designers felt the need to make the text input ever so slightly diferent from LaTeX so there is no easy reference, and there is no good way to put your equations in the paper without them sticking out like a mangled sore thumb.
  • LyX  – LyX attempts to bring together the strengths of LaTeX and Word. It succeeds, delivering a LaTeX-based (so, flexible and standardized) WYSIWYG experience. Unfortunately, it also brings together the weaknesses of LaTeX and Word, combining a steep learning curve with annoying rigidities.
  • Handwriting Recognition – a much newer entrant, there are a few emerging apps which attempt to mimic the ease of writing math on paper. My phone does a surprisingly good job (if I devote a lot of attention to making my symbols large and well spaced.) Unfortunately it will only export the equations as an image. Myscript mathpad purports to export your handwriting as standard LaTeX code, but I haven’t used it or talked to anybody who has.

Peeking Behind the Curtain

I think a big goal of a research blog like this one should be to give you a glimpse into the sausage factory of research. Too often, it seems, labs are black boxes that spit out polished papers every so often. This one-dimensional way of conveying science has its pros and cons. Regardless of how you feel about the paper system, it’s pretty clear that research labs can add value through non-paper insights. We have a group of smart people slamming their heads against cool problems every day – surely that generates more worth sharing than a couple of paper’s worth a year.

Hopefully, this value can come in several forms – what we’re doing, why we’re doing it, and how we’re going about it. Most of my posts have focused on the first two questions, looking at the big picture ‘why?’ and what we’re actually doing to tackle each challenge.

Sharing the ‘how’ is trickier. Anybody in the lab could spend hours on the nitty-gritty details of a very specific problem and the tools they’re using to tackle those details. That’s pretty yawn inducing unless you’re looking at that exact same problem or can do the mental long-jump to apply those details to your own problem. However, labs do come up with neat tools (software or hardware) all the time, but often they aren’t significant enough to publish and stay ‘in-house’ or worse, are just forgotten when whoever made them graduates.

One solution is open-sourcing these tools. Open sourcing is a much more common practice in computer science that mechanical engineering would gain from. To try to get the ball rolling, I’ve started a GitHub repository for QuIRK, the multibody dynamics simulator.  I will update it soon with QuIRK-E – my electromagnetics add-on. If you’re interested, check it out. If you’ve never heard of Git, it’s essentially a framework for many people to work on the same piece of software at once, without getting in each other’s way too badly. Zac put the code for ChipSats on GitHub as well.

Do you have ideas on how labs can share in useful out-of-paper ways? Let us know!