MacCallister Higgins’s Tweets

· Sep 1

Guys don’t tell my girlfriend but I’ve found the holy grail of government auctions.

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Martin Austermuhle

@maustermuhle

· 20h

Interesting: @charlesallen has an emergency bill that would empower the D.C. Department of For-Hire Vehicles to ticket Uber and other drivers who double park, block bike lanes, and otherwise break traffic laws when delivering food and the like. lims.dccouncil.gov/Legislation/B2

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Sep 19

Been to my local Thai place 8 times in the two months that I’ve been here, and today is the first time they’ve trusted me with their non-American spicy levels. I am shook. This feels like taking pepper spray to the face. I love it.

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Josh Gondelman

@joshgondelman

Sep 17

Maine feels like it’s constantly on the border of a farmers market and a militia. The whole vibe is: “You can pry these locally grown blueberries from my cold dead hands.”

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Actual ad for anyone interested:

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Pratt & Whitney

@prattandwhitney

· Jun 30

F135 EEP meets the needs of Block 4 and beyond for all F-35 operators – while saving the taxpayer $40B in lifecycle costs. It’s a no brainer.

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Part of the fun of living in DC is receiving ads that are clearly targeted at federal policy folks, but that tangentially overlap with your interests.

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Balaji Srinivasan

@balajis

A head of PR without a social media following is like a head of engineering that can’t code.

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Sebastian Bille

@TastefulElk

The single most expensive phrase in software engineering: "Maybe we should just build it ourselves instead?"

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Amjad Masad ⠕

@amasad

Sep 15

Announcing: History++ a better way of doing version control. blog.replit.com/history2-relea

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ROS1 robots in a ROS2 world

Black Coffee Robotics

@bcrllp

Sep 15

ROS1 or ROS2? Why not both? We built a lean communication bridge to run ROS1 robots in a ROS2 ecosystem (and open sourced it!). Read on! link.medium.com/n16pwQloltb #fleetmanagement #amrs #opensource #robotics #ros #ros2

link.medium.com

ROS1 has borne the burden of supporting applications for robots for well over a decade. May 2025 will be the EoL for ROS Noetic — the…

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Sad you missed out on this and want to fill that airstream-sized hole in your heart? How about buying a real rocket engine?

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· Sep 16

Need an oxygen/hydrogen rocket engine that produces 300,000 pounds of thrust? Maybe you're building your own SLS and need a boost for that second stage? Make your dreams reality and bid on the J2X engine from NASA, with auctions closing today (links and parts breakdown in

)!

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Luke Beard

@LukesBeard

Turns out, I do need one. Thanks

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· Sep 16

Need an oxygen/hydrogen rocket engine that produces 300,000 pounds of thrust? Maybe you're building your own SLS and need a boost for that second stage? Make your dreams reality and bid on the J2X engine from NASA, with auctions closing today (links and parts breakdown in

)!

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J-2X Rocket Engine Gimbal Test | NASA Stennis Space Center Science...

J2X breakdown sheet from NASA (2011):nasa.gov/pdf/528269main

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Full video of the J2X gimbal test, where I got the gif in the first tweet:

youtube.com

Visit my website at http://www.junglejoel.com - a J-2X rocket engine is gimbal tested at Stennis Space Center, June 14, 2013. The J-2X will power the upper s...

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Extra links: Here's an old newsletter from Michoud about SLS progress, specifically citing the J2X as the intended second stage engine: nasa.gov/centers/marsha

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Here's the link to Lot 1, and you can find the rest just by typing "J2X" into the search bar on the GSA site. Good luck, and let me know if you win anything! gsaauctions.gov/gsaauctions/au

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The auction that is ending today is incredibly comprehensive, with the lots for sale containing everything from "the smallest bolt to the combustion chamber for the engine." The best part? These are completely unused, just waiting to be displayed and assembled.

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Today, the SLS is assembled at Michoud, and the reused Space Shuttle Main Engine RS-25s can be seen on this image of the core stage at the assembly facility. The J2X was originally going to be used for the SLS upper stage, but it was replaced by the RL10 (also Aerojet Rocketdyne)

The first SLS core stage, nearing completion at the Michoud Assembly Facility late last year. With the center moving down to Stage 3 of NASA's response framework, some work on the second SLS core stage will be able to resume there. Credit: NASA/Jude Guidry

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So what are these J2X parts doing in Louisiana? The Michoud Assembly Facility! Originally built by Higgins Industries (no relation) for WW2 manufacturing, and used throughout America's space program - here's a few Saturn V primary stages being assembled there with J2 engines.

By NASA - http://www.nasa.gov/centers/marshall/moonmars/apollo40/saturnV_stages.htmlhttp://mix.msfc.nasa.gov/abstracts.php?p=1113, Public Domain, https://commons.wikimedia.org/w/index.php?curid=443475

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If you're looking for something specific, like the combustion chamber or the gimbal assembly, I've obtained a complete breakdown of parts from each lot from the housing facility. I've uploaded it in a searchable format on google drive, so go crazy: bit.ly/3QQAZVx

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A "lot" is how they separate out what is being bid on, so you're going to be pretty busy today jumping between auctions to get the full collection of all the the J2X assembly components that are broken up into 8 different (!) auctions.

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This auction is less of a mystery than the NVCC: "This sale is a group of 8 lots of material that will assemble the J2X rocket engine" -- pretty straight forward, unless of course you are looking for something specific. This photo is just from a single lot!

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While cost was a design goal, the Space Launch System (aka SLS, the launch that scrubbed earlier this month) hasn't exactly been a paragon of frugality, and the J2X was no different. It cost $1.2 BILLION to design this engine -- and it can now be yours for probably less than $20k

A-1 Test Stand Houses First Full Engine in Nearly a Decade. Image credit: NASA/SSC

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Back to the rocket engine. The J2X was intended to be an evolution of the Apollo-era J2 engine, used on Saturn Rockets (photo). Due to thrust requirements and a desire to make a cheaper engine than the RS-25, Aerojet started from scratch in 2007 on this new design for the SLS.

By Torsten Bolten - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=7319986

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First, I had no idea my previous thread on the NASA Convoy Command Vehicle would get so much traction. I do this stuff for fun, so why not make it a thing? Give me a follow to keep seeing these kinds of auctions and weird government liquidations.

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· Sep 12

Ok, I’m not going to be able to buy and restore this due to logistics so I figured I’d throw it up on Twitter. Long story short, I found the @NASA Convoy Command Vehicle for the Space Shuttle program up for auction, with almost zero indication of what it is (link at end of

) twitter.com/macjshiggins/s…

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Need an oxygen/hydrogen rocket engine that produces 300,000 pounds of thrust? Maybe you're building your own SLS and need a boost for that second stage? Make your dreams reality and bid on the J2X engine from NASA, with auctions closing today (links and parts breakdown in 🧵)!

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Latest in space

@latestinspace

Sep 15

BREAKING 🚨: NASA's Perseverance rover has found organic matter in rock samples on Mars

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Replying to

I'm still of the old school hacker opinion that totalitarian hellscape vs cyberpunk anarchy depends entirely on whether p=np, and the odds are in our favor

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Suhail

@Suhail

Sep 14

Every. Single. Week. There's. A. Breakthrough.

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Adept

@AdeptAILabs

· Sep 14

1/7 We built a new model! It’s called Action Transformer (ACT-1) and we taught it to use a bunch of software tools. In this first video, the user simply types a high-level request and ACT-1 does the rest. Read on to see more examples

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Faraz Khan

@faraz_r_khan

Sep 14

What I'm working on these days: A full suspension long tail all-wheel drive electric cargo bike since carrying your kids to school should not only be safe on bumpy roads but fun. Throttle only to allows safe starts on hills, integrated BT lock, giant 2kwh batt for 80mi range

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Garrett Scott

@thegarrettscott

Sep 14

We just reopened our wildcard role! Most of our team are former founders for a reason, what we’re doing a lot of outside-the-box thinking. It doesn’t matter to us what your background is, if you’re naturally curious & good at figuring things out quickly, PLS APPLY!

Pipedream Labs

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I solemnly hope, no — pray, that zero startups make a decision on their tool chain based on this information. Unless you are doing massively distributed embedded hardware from day 1 (hint: you aren’t), please don’t optimize like this.

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Alex Xu

@alexxubyte

· Sep 12

/1 𝐖𝐡𝐚𝐭 𝐀𝐫𝐞 𝐭𝐡𝐞 𝐆𝐫𝐞𝐞𝐧𝐞𝐬𝐭 𝐏𝐫𝐨𝐠𝐫𝐚𝐦𝐦𝐢𝐧𝐠 𝐋𝐚𝐧𝐠𝐮𝐚𝐠𝐞𝐬 [1]? The study below runs 10 benchmark problems in 28 languages. It measures the runtime, memory usage, and energy consumption of each language. The abstract of the paper is shown below.

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What a story by

! This should be in a museum, I don't understand why the government is even selling it.

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· Sep 12

Ok, I’m not going to be able to buy and restore this due to logistics so I figured I’d throw it up on Twitter. Long story short, I found the @NASA Convoy Command Vehicle for the Space Shuttle program up for auction, with almost zero indication of what it is (link at end of

) twitter.com/macjshiggins/s…

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· Sep 14

Replying to @macjshiggins and @NASA

Hi MacCallister, thanks for the story, effort, and thread. Way cool! I worked on the Shuttle Launch and Landing Team at KSC for 23 years, and was a landing team member at EAFB for many missions. As an orbiter move director, I walked behind that RV on the tow back, and she's real!

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and

Hi MacCallister, thanks for the story, effort, and thread. Way cool! I worked on the Shuttle Launch and Landing Team at KSC for 23 years, and was a landing team member at EAFB for many missions. As an orbiter move director, I walked behind that RV on the tow back, and she's real!

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Canon Reeves

@ReevesCanon

Sep 13

Pipedream Tech Update: August 2022

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This is absurdly exciting. Underground robots here we come.

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Drew

@drew_bellcock

· Sep 13

Pipes in the ground. This year. twitter.com/drew_bellcock/…

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Drew

@drew_bellcock

Sep 13

Pipes in the ground. This year.

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Drew

@drew_bellcock

· Jan 3

Pipes in the ground this year.

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Sep 13

A follower reached out with a story from their father, a former Flow Director that regularly worked out of this Convoy Command Vehicle. Absolutely worth the read.

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