Terra Bella Blog: March 2014

Blog

The latest news from the Terra Bella team

SkySat-1 Launch Campaign: Behind the Scenes

Friday, March 28, 2014

Google

Building the World's Most Capable Microsatellites, Part 2

Wednesday, March 19, 2014

In Part I we explored why the time is ripe for small imaging satellites. While building SkySat-1 and the data infrastructure that surrounds it, we have developed a set of design principles that are steeped in the fast-paced, creative engineering culture of Silicon Valley but also draw extensively from 60 years of US space experience.

Here in Part II we expound upon these principles, explaining how they enable us to build phenomenally capable products within tight time and resource constraints. We start with one that sounds obvious…

Do the right thing

Striking the balance between time to do the right thing and the need to move faster, faster, faster is difficult but can be make-or-break for a small organization. We challenge our team every day to do the right thing.

That dimension matters

Simplicity

There is a famous saying (often attributed to Einstein):

Make things as simple as possible but not simpler.

Starting with the goal of simplicity has huge implications as a design matures. It makes debugging and testing easier. It keeps cost down and it allows for easier evolution of the design.

Simplicity doesn’t just happen - it requires deep thought, discipline and many iterations. “Can we make it simpler?” is a question you will hear in almost every design review at Skybox.

Modularity

Modularity is an aspect of design that takes discipline and a long view, but enables fast progress in the face of uncertainty. It is absolutely necessary in a startup environment because it allows the team to react quickly to changing business requirements and postpone decisions.

A truly modular system (software or hardware) allows for change in a component or subsystem without large, system-wide impact. This flexibility makes it possible to postpone decisions until better information is available. Turns out that in a startup better information flows in every day.

Let's swap this one out

Hiring hands-on engineers that build on a modular architecture makes it cheap to try things, fail and try again. The goal of testing is not necessarily to succeed - it is to uncover points of failure early and fix them. That is how you find weaknesses in a design and create true robustness.

Our hardware engineers are itching to get out from behind a computer monitor and our software engineers build tests before they implement features. One of our core beliefs is that there’s no such thing as too much testing if you can afford it.

Where does this screw go? A little to the right…

In fact, we find excuses to integrate and test things early in a design cycle. Even if contrived, the time spent putting things together early is paid back many times over as the design matures.
Balance

Much of engineering is about striking balances. Recognizing that is an important first step. But we also need guidelines to help us in finding those balances. Here’s a snapshot of some of the balances we weigh in engineering everyday at Skybox.

Right-sized analysis

George E. P. Box wrote that “… all models are wrong, but some are useful.”

Analysis is critical to design - without it quantifying the merit of design choices is practically impossible. However it is all-to-often that design teams spend inordinate time and resources on complex models that nature shows to be inaccurate anyway

Your timestep is too large

You can’t do everything yourself… Do everything yourself!
This is one of the hardest balances for us and one we wrestle with every day. We care more than anyone else about what we’re building and we have the best team in the world. So why shouldn’t we make it all?

But with a small team building a large and complex system, it is simply unrealistic to do everything in-house.

Can you hear me now?
A corollary to this is to have good in-house infrastructure. Being able to build things ourselves enables quick hardware iteration cycles and the flexibility to pull something in-house if we need to. To that end, we’ve built lab and shop space here to make everything from quick-turn prototypes to parts that will fly in space.

Making chips Ford or Ferrari?

Engineers love performance - squeezing as much capability out of a system as is possible. And while optimization is important for building small, tightly integrated systems with tight resource constraints, it can also lead to a fragile design. Effective design optimization balances performance in an ideal case with resiliency in the face of off-nominal conditions.

Redundancy is NOT the root of all evil

Redundancy is a powerful tool in the fight to build a robust system. It is also seemingly in direct conflict with the simplicity maxim. Thus redundancy has become a bad word in many scaled-down aerospace systems.

We believe redundancy is a good thing, it just has to be applied intelligently. A modular architecture enables targeted redundancy without permutational complexity and we make redundancy a goal not a requirement.

The delicate balance of simplicity and targeted redundancy can lead to a robust, capable and elegant system.

Leverage other industries

In engineering if there’s an easy way out of a challenge that doesn’t compromise other principles it’s foolish not to take it.

Technical problems in one industry are often similar to technical problems in other industries. And while there are factors and constraints in what we’re doing that are absolutely unique, there are also many areas where great technologies exist in other industries that are applicable to our needs and can save a lot of time. Here are a few places where we “cheat” by pulling from other industries. We have heavily leveraged technology from the consumer electronics, industrial automation, and automotive industries.

The consumer electronics industry has invested $100 billion’s over the past 50 years in packing miraculous technology in tiny footprints. Your iPhone is the direct beneficiary of this. Here are five technologies that are as enabling to a satellite imaging platform as they are to an iPhone:

Super-computer level processing performance in tiny space / power footprint

Sensitive, fast and high resolution CMOS image sensors

Compact, high efficiency solid state radio components

High energy-density lithium-ion batteries

Dense, fast and robust solid-state FLASH memory

Picture that
Unfortunately, the technology used in space electronics lags its commercial counterpart by 2-3 generations due to risk aversion and the cost of the traditional space-hardening processes. Moreover, massive investment in process control has made today’s COTS parts incredibly reliable - especially those targeted at automotive or industrial applications.

One of the most critical enablers for our satellites are proprietary design, test and screening processes that enable us to fly cutting-edge COTS parts in the space environment. Commercial parts let us prototype quickly and cheaply, utilize technology years ahead of typical space missions and still have high confidence in the reliability of the system.

Conclusion

In Part III we will show how we applied these principles to the design of SkySat-1, elaborate on the way we balanced capability vs. size, and why we think the SkySat platform is right in the sweet-spot.
Posted by Jonny Dyer, Chief Engineer

Google

In search of Malaysia Airlines Flight 370

Thursday, March 13, 2014

We are actively tasking the first satellite of our constellation, SkySat-1, to take high-resolution images and full motion video over several targets spanning between Kuala Lumpur and Ho Chi Minh city. We are currently leveraging early SkySat-1 capabilities to collect focused area targets. As our constellation grows over the coming years, our capability to collect larger areas at higher revisit rates will increase. We are engaging with subject matter experts and partners to analyze our images. If any glimmer of a clue emerges, we will publish any information here on our blog. Below is an interactive map created by Mapbox showing the imagery footprints from SkySat-1 and other satellite providers over the last 6 days.Our hearts are with the families of the passengers and crew onboard.

Google

ECAPS to Supply Green Propulsion for 12 More SkySat Satellites

Tuesday, March 11, 2014

We are pleased to announce our continued partnership wtih ECAPS, an SSC Group Company, for 12 additional high performance green propulsion (HPGP) systems for our planned constellation of 24 high-resolution imaging and video-capable satellites.The 12 HPGP system modules included in this new contract are to be delivered during 2015 and 2016. We previously awarded ECAPS a contract for a modular HPGP system for our SkySat-3 satellite, which will be the first of our satellites to be equipped with an orbit maneuvering capability.“The propulsion modules will enable us to support a wide range of mission orbits to meet our customers’ demands for high-temporal, high-resolution imagery and video,” said Mike Trela, our VP of Satellite Systems, who noted that the agreement also “extends Skybox’s company culture of environmental responsibility.” For more information on this news, please click here.

Google

Company-wide

Official Google Blog
Research Blog
Student Blog

Products

Lat Long Blog
Official Android Blog
Chrome Blog

Developers

Developers Blog
Geo Developers Blog
Android Developers Blog

Google
Privacy
Terms

Blog

SkySat-1 Launch Campaign: Behind the Scenes

Building the World's Most Capable Microsatellites, Part 2

In search of Malaysia Airlines Flight 370

ECAPS to Supply Green Propulsion for 12 More SkySat Satellites

Archive

Company-wide

Products

Developers