Welcome!

Java IoT Authors: Yeshim Deniz, Pat Romanski, Liz McMillan, Elizabeth White, Zakia Bouachraoui

Related Topics: Java IoT

Java IoT: Article

Software Testing Shouldn't Be Rocket Science

Software Testing Shouldn't Be Rocket Science

Earthdate: October 15, 1997, and the Cassini spacecraft is launched. Mission: to boldly go and explore the planet Saturn.

Saturn is about 10 times farther away from the Sun than the Earth, and to get there required two orbits of the inner solar system, receiving gravitational kicks from Venus and Earth before doing a flyby of Jupiter to get a final assist toward Saturn.

Piggy-backed to Cassini was the Huygens probe that would be dropped onto Saturn's moon, Titan. Unlike most other moons in the solar system that are barren, cratered rocky places, Titan has an atmosphere covering it. The purpose of the probe was to parachute through this, capturing data as it descended onto the planet's surface. The data would be transmitted from the probe up to the Cassini craft, which would act as a relay and transmit back to earth where the experiments' results would be analyzed.

On January 14, 2005, Huygens successfully landed on Titan's surface and provided some fantastic pictures of the moon (www.esa.int/SPECIALS/Cassini-Huygens/index.html). Despite this, there were two major problems on the mission.

The first is that one of the radio channels that the Huygens craft was going to use to transmit data to Cassini failed. The remaining channel was used successfully, although due to this problem only half of Huygen's pictures have come back and some experiments have had all their data lost. The reason for the problem is described as a "software commanding error." The reality is the receiver on Cassini was never programmed to switch on.

The second problem is related to the premise that Huygens transmits its collected data to the Cassini orbiter, which then relays it back to earth. Three years after the launch one of the space agency's employees became uneasy about the fact that this feature hadn't been tested enough in realistic conditions. The story is described in detail at www.spectrum.ieee.org/WEBONLY/publicfeature/oct04/1004titan.html and provides a sobering lesson in the importance of testing. This employee worked hard to convince colleagues and superiors of the importance of testing the link in real conditions, so a simulation was done by sending data from earth to Cassini mid-mission while it hurtled toward Saturn. This mimicked the separation conditions that would be encountered between the craft and Titan and the raw data sent was echoed back to earth by Cassini and analyzed. It showed a fundamental flaw.

Because of the difference in the relative speeds at which Cassini was traveling in space relative to Huygens, there was a Doppler shift. A Doppler shift is when waves are effectively compressed if the receiver and source are moving toward each other and expanded if moving apart. As the wavelength decreases, the frequency increases, meaning that Cassini would have to adjust its listening frequencies to account for its velocity relative to the Huygens transmitter. In addition, the decoding would be affected. Digital data is split into ones and zeros and compared against a base signal to decipher; however, the Doppler shift would stretch and compress the lengths of the payload actual bits in the wave, meaning the digital signal couldn't be analyzed correctly. A fix was required to rescue the $3.26 billion project.

Despite the fact that Cassini's hardware allows its receiver to receive over a range of shifted frequencies, the firmware program was unable to be modified after launch, even though a small fix would have sufficed. The solution they used was to alter the trajectory of Cassini's orbits of Titan so that the craft's approach allowed the radio transmissions to travel perpendicular to its direction of motion, thereby reducing the Doppler shift.

The cost of the two Cassini bugs is huge. Coming down to earth it provokes questions about testing in general. A trait I've encountered at times in my career is for a program to be released knowing it is flawed because the programmer hopes to release the working version in a subsequent fixpack, hopefully before the user has encountered the errant feature. Upgrading releases is easy for developers, but for a user who has to migrate data and schedule business downtime it's frustrating and must contribute to the perception that the latest release is not a set of fully baked features but a rollup of the previous version's fixes bundled with new features that perpetually introduce their own set of bugs.

Good testing is about attitude, where a developer takes pride not just in the elegance or volume of his or her code, but in whether it meets the user's requirements and performs reliably in its first incarnation. I once heard a developer say that releasing buggy code was part of agile programming to allow you to have more cycles of code/release//fix/code. Apart from not grasping the methodology maturely, it showed a basic lack of pride in their work that they were trying to justify. The same excuses can also lead to bloatware, where code is thrown upon code without any tight design or following the basic principles of software engineering. Is the problem that some developers are incapable of taking pride in the complete quality of their work, or that education and teaching, or marketing pressures in a commercial environment still mean that buggy software is released. Next time you release code without proper testing, keep in mind the Cassini programmers who had to physically alter their craft's passage to find a solution. While we might have the next fixpack or release available to us, in space no one can hear your excuses.

More Stories By Joe Winchester

Joe Winchester, Editor-in-Chief of Java Developer's Journal, was formerly JDJ's longtime Desktop Technologies Editor and is a software developer working on development tools for IBM in Hursley, UK.

Comments (1)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


IoT & Smart Cities Stories
Dion Hinchcliffe is an internationally recognized digital expert, bestselling book author, frequent keynote speaker, analyst, futurist, and transformation expert based in Washington, DC. He is currently Chief Strategy Officer at the industry-leading digital strategy and online community solutions firm, 7Summits.
Digital Transformation is much more than a buzzword. The radical shift to digital mechanisms for almost every process is evident across all industries and verticals. This is often especially true in financial services, where the legacy environment is many times unable to keep up with the rapidly shifting demands of the consumer. The constant pressure to provide complete, omnichannel delivery of customer-facing solutions to meet both regulatory and customer demands is putting enormous pressure on...
IoT is rapidly becoming mainstream as more and more investments are made into the platforms and technology. As this movement continues to expand and gain momentum it creates a massive wall of noise that can be difficult to sift through. Unfortunately, this inevitably makes IoT less approachable for people to get started with and can hamper efforts to integrate this key technology into your own portfolio. There are so many connected products already in place today with many hundreds more on the h...
The standardization of container runtimes and images has sparked the creation of an almost overwhelming number of new open source projects that build on and otherwise work with these specifications. Of course, there's Kubernetes, which orchestrates and manages collections of containers. It was one of the first and best-known examples of projects that make containers truly useful for production use. However, more recently, the container ecosystem has truly exploded. A service mesh like Istio addr...
Digital Transformation: Preparing Cloud & IoT Security for the Age of Artificial Intelligence. As automation and artificial intelligence (AI) power solution development and delivery, many businesses need to build backend cloud capabilities. Well-poised organizations, marketing smart devices with AI and BlockChain capabilities prepare to refine compliance and regulatory capabilities in 2018. Volumes of health, financial, technical and privacy data, along with tightening compliance requirements by...
Charles Araujo is an industry analyst, internationally recognized authority on the Digital Enterprise and author of The Quantum Age of IT: Why Everything You Know About IT is About to Change. As Principal Analyst with Intellyx, he writes, speaks and advises organizations on how to navigate through this time of disruption. He is also the founder of The Institute for Digital Transformation and a sought after keynote speaker. He has been a regular contributor to both InformationWeek and CIO Insight...
Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settlement products to hedge funds and investment banks. After, he co-founded a revenue cycle management company where he learned about Bitcoin and eventually Ethereal. Andrew's role at ConsenSys Enterprise is a mul...
To Really Work for Enterprises, MultiCloud Adoption Requires Far Better and Inclusive Cloud Monitoring and Cost Management … But How? Overwhelmingly, even as enterprises have adopted cloud computing and are expanding to multi-cloud computing, IT leaders remain concerned about how to monitor, manage and control costs across hybrid and multi-cloud deployments. It’s clear that traditional IT monitoring and management approaches, designed after all for on-premises data centers, are falling short in ...
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
Dynatrace is an application performance management software company with products for the information technology departments and digital business owners of medium and large businesses. Building the Future of Monitoring with Artificial Intelligence. Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more busine...