0

Remembering Challenger at 30 Years

space-shuttle-challenger-crew

On January 28th, 1986, I was sitting in a hardware lab at the WVU engineering sciences building tinkering with an old 16-bit computer system, a DEC PDP variant with a floating-point processing module called a “SKYMNK-M” installed, when the news came over the radio that the Challenger launch of mission STS-51L had exploded two minutes after liftoff.  I ran to the elevators and went down to the student lounge to see the TV coverage for pretty much the rest of the day.  There was some discussion among the students and staff at the time as to what had happened.  We had covered issues such as the launch temperature and if an SRB blew up or the main fuel tank ruptured.  This discussion would end up being the major topic and assignment of my EE343 class.  We were asked to study the problem and provide solutions and to assign blame for what had happened so steps could be taken that it would never happen again.

Dr. Feynman’s famous demonstration of how the SRB O-rings became brittle in freezing weather was a point of interest, but the primary revelation we had that semester is that the SRBs were based on a Atlas booster design, but the casing was inverted, meaning that the expansion pressure meant to close the O-ring seals did not in fact work as the inner ring was situated on the lower casing, and the lift pressure caused the outer ring of the joint to expand, defeating the O-ring seal in freezing temperatures.  Blame was easy to assign: Morton-Thiokol, designer of the Atlas booster, won the SRB contract in the mid-1970s, being the cheapest of the contracts in competition and were found at fault in the months after the disaster.  Allan McDonald, the NASA engineer in charge of the SRB project with Morton-Thiokol in fact had refused to sign off on the launch recommendation, citing concerns over O-ring seal integrity in freezing temperatures.  McDonald recounts his experiences in his Book, Truth, Lies and O-rings: Inside the Space Shuttle Disaster, which is recommended for anyone in the design field.

Allan McDonald on SRBs post-Challenger

Challenger represents one of the lessons people tend to forget: aerospace design is hard.  Most of what has been done is still considered experimental, and experiments fail all the time.  The “problem” with the shuttle program of the 1980s leading up to Challenger is that it got perhaps a little too confident and started to make decisions based more on politics and less on protocol. Robert Crippen and John Young were in full pressure suits for the first launch of Columbia in 1981, and by the time the Challenger disaster happened, people were in shirt sleeves and we were sending senators up into orbit (I will allow a pass for John Glenn, a senator who was an astronaut first).

So even if Challenger at 30 seems a distant memory, look no further than the SpaceX barge landing issues to realize that while we’re making great advances in aerospace, it is still an experiment, and everything has to be rigorously tested every single time.

 

Crow

/**/


Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Join 12,000+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython 2019!

Have an amazing project to share? The Electronics Show and Tell with Google Hangouts On-Air is every Wednesday at 7:30pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Follow Adafruit on Instagram for top secret new products, behinds the scenes and more https://www.instagram.com/adafruit/


Maker Business — Trade war rolls on, effects will have lasting implications

Wearables — Block the light

Electronics — Stay disciplined with ERC

Biohacking — Focus Building Meditation with Michael Taft

Python for Microcontrollers — Consumers Should Immediately… Python the Circuit! #Python #Adafruit #CircuitPython #PythonHardware @circuitpython @micropython @ThePSF @Adafruit

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !



2 Comments

  1. This source says Morton Thiokol wasn’t the cheapest option:

    http://www.tsgc.utexas.edu/archive/general/ethics/boosters.html

    It also goes on to say that United Technologies (bid the same cost as Morton Thiokol) had much more experience with building large solid rockets.

  2. Thanks for the correction. I am going mostly from memory here.

Sorry, the comment form is closed at this time.