jm + nasa   11

Who Discovered Why The Challenger Exploded?
Everyone knows Richard Feynman’s famous televised demonstration that the Challenger had exploded because its O-rings got stiff when they were cold -- but it wasn’t Feynman’s discovery. It was Sally Ride’s.'

(via Tony Finch)
richard-feynman  sally-ride  history  space  challenger  o-rings  science  engineering  nasa 
26 days ago by jm
Building the plane on the way up
in 1977, Jet Propulsion Lab (JPL) scientists packed a Reed-Solomon encoder in each Voyager, hardware designed to add error-correcting bits to all data beamed back at a rate of efficiency 80 percent higher than an older method also included with Voyager. Where did the hope come in? When the Voyager probes were launched with Reed-Solomon encoders on board, no Reed-Solomon decoders existed on Earth.
reed-solomon  encoding  error-correction  voyager  vger  history  space  nasa  probes  signalling 
january 2017 by jm
Mars One finalist Dr. Joseph Roche rips into the project
So, here are the facts as we understand them: Mars One has almost no money. Mars One has no contracts with private aerospace suppliers who are building technology for future deep-space missions. Mars One has no TV production partner. Mars One has no publicly known investment partnerships with major brands. Mars One has no plans for a training facility where its candidates would prepare themselves. Mars One’s candidates have been vetted by a single person, in a 10-minute Skype interview.

“My nightmare about it is that people continue to support it and give it money and attention, and it then gets to the point where it inevitably falls on its face,” said Roche. If, as a result, “people lose faith in NASA and possibly even in scientists, then that’s the polar opposite of what I’m about. If I was somehow linked to something that could do damage to the public perception of science, that is my nightmare scenario.”
science  space  mars-one  tcd  joseph-roche  nasa  mars  exploration  scams 
march 2015 by jm
A Case Study of Toyota Unintended Acceleration and Software Safety
I drive a Toyota, and this is scary stuff. Critical software systems need to be coded with care, and this isn't it -- they don't even have a bug tracking system!
Investigations into potential causes of Unintended Acceleration (UA) for Toyota vehicles have made news several times in the past few years. Some blame has been placed on floor mats and sticky throttle pedals. But, a jury trial verdict was based on expert opinions that defects in Toyota's Electronic Throttle Control System (ETCS) software and safety architecture caused a fatal mishap.  This talk will outline key events in the still-ongoing Toyota UA litigation process, and pull together the technical issues that were discovered by NASA and other experts. The results paint a picture that should inform future designers of safety critical software in automobiles and other systems.
toyota  safety  realtime  coding  etcs  throttle-control  nasa  code-review  embedded 
january 2015 by jm
How Curiosity, Luck, and the Flip of a Switch Saved the Moon Program | Motherboard
"SCE to off?" someone said. The switch was so obscure that neither of his bosses knew what he was talking about. "What the hell's that," blurted out Gerald Carr, who was in charge of communicating with the capsule. The rookie flight director, Gerry Griffin, didn't know either.

Sixty seconds had passed since the initial lightning strike. No one else knew what to do. The call to abort was fast approaching. 

Finally, Carr reluctantly gave the order in a voice far cooler than the moment. "Apollo 12, Houston, try SCE to Auxiliary, over."
spaceflight  stories  apollo  sce-to-aux  power  lightning  weather  outages  simulation  training  nasa 
november 2014 by jm
Rope-core memory
as used in the Apollo guidance computer systems -- hand-woven by "little old ladies". Amazing
core-memory  memory  rope-core  guidance  apollo  space  nasa  history  1960s  via:hn 
april 2014 by jm
VERY high resolution scans of original Apollo 11 and Apollo 14 charts
the Apollo 11 ALO and LM Descent Monitoring charts are tidied up and downloadable
apollo  space  history  memorabilia  images  scans  science  nasa 
april 2014 by jm
JPL Institutional Coding Standard for the Java Programming Language
From JPL's Laboratory for Reliable Software (LaRS). Great reference; there's some really useful recommendations here, and good explanations of familiar ones like "prefer composition over inheritance". Many are supported by FindBugs, too.

Here's the full list:

compile with checks turned on;
apply static analysis;
document public elements;
write unit tests;
use the standard naming conventions;
do not override field or class names;
make imports explicit;
do not have cyclic package and class dependencies;
obey the contract for equals();
define both equals() and hashCode();
define equals when adding fields;
define equals with parameter type Object;
do not use finalizers;
do not implement the Cloneable interface;
do not call nonfinal methods in constructors;
select composition over inheritance;
make fields private;
do not use static mutable fields;
declare immutable fields final;
initialize fields before use;
use assertions;
use annotations;
restrict method overloading;
do not assign to parameters;
do not return null arrays or collections;
do not call System.exit;
have one concept per line;
use braces in control structures;
do not have empty blocks;
use breaks in switch statements;
end switch statements with default;
terminate if-else-if with else;
restrict side effects in expressions;
use named constants for non-trivial literals;
make operator precedence explicit;
do not use reference equality;
use only short-circuit logic operators;
do not use octal values;
do not use floating point equality;
use one result type in conditional expressions;
do not use string concatenation operator in loops;
do not drop exceptions;
do not abruptly exit a finally block;
use generics;
use interfaces as types when available;
use primitive types;
do not remove literals from collections;
restrict numeric conversions;
program against data races;
program against deadlocks;
do not rely on the scheduler for synchronization;
wait and notify safely;
reduce code complexity
nasa  java  reference  guidelines  coding-standards  jpl  reliability  software  coding  oo  concurrency  findbugs  bugs 
march 2013 by jm
Knots on Mars! (and a few thoughts on NASA's knots)
amazing post from the International Guild of Knot Tyers Forum:

While a few of the folks here are no doubt aware, it might surprise most people to learn that knots tied in cords and thin ribbons have probably traveled on every interplanetary mission ever flown. If human civilization ends tomorrow, interplanetary landers, orbiters, and deep space probes will preserve evidence of both the oldest and newest of human technologies for millions of years.

Knots are still used in this high-tech arena because cable lacing has long been the preferred cable management technique in aerospace applications. That it remains so to this day is a testament to the effectiveness of properly chosen knots tied by skilled craftspeople. It also no doubt has a bit to do with the conservative nature of aerospace design and engineering practices. Proven technologies are rarely cast aside unless they no longer fulfill requirements or there is something substantially better available.

While the knots used for cable lacing in general can be quite varied -- in some cases even a bit idiosyncratic -- NASA has in-house standards for the knots and methods used on their spacecraft. These are specified in NASA Technical Standard NASA-STD-8739.4 -- Crimping, Interconnecting Cables, Harnesses, and Wiring. As far as I've been able to identify in the rover images below, all of the lacings shown are one of two of the several patterns specified in the standard.

The above illustration shows the so-called "Spot Tie". It is a clove hitch topped by two half-knots in the form of a reef (square) knot. In addition to its pure binding role, it is also used to affix cable bundles to tie-down point.

Some amazing scholarship on knot technology in this post -- lots to learn! (via Tony Finch, iirc)
via:fanf  mars  nasa  science  knots  tying  rope  cables  cabling  geek  aerospace  standards 
september 2012 by jm
NASA's Mars Rover Crashed Into a DMCA Takedown
An hour or so after Curiosity’s 1.31 a.m. EST landing in Gale Crater, I noticed that the space agency’s main YouTube channel had posted a 13-minute excerpt of the stream. Its title was in an uncharacteristic but completely justified all caps: “NASA LANDS CAR-SIZE ROVER BESIDE MARTIAN MOUNTAIN.”

When I returned to the page ten minutes later, [...] the video was gone, replaced with an alien message: “This video contains content from Scripps Local News, who has blocked it on copyright grounds. Sorry about that.” That is to say, a NASA-made public domain video posted on NASA’s official YouTube channel, documenting the landing of a $2.5 billion Mars rover mission paid for with public taxpayer money, was blocked by YouTube because of a copyright claim by a private news service.
dmca  google  fail  nasa  copyright  false-positives  scripps  youtube  video  mars 
august 2012 by jm
The Moon Museum
a Grumman engineer, working with artist Frosty Myers, hid a tiny ceramic plate of modern art on one leg of the Apollo 12 moon lander -- including a crude penis drawn by Andy Warhol
1960s  art  culture  funny  hack  history  museums  space  nasa  apollo  andy-warhol  from delicious
november 2010 by jm

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