Launching Rockets Is Hard, Bringing Them Back Is Harder

Since the first V2 rocket sailed above the Kármán line back in 1944 and right up until the modern era, the trajectory of most space-bound rockets was more or less the same: after expending their propellants they would either crash into some desolate steppe or plunge into the ocean. In either event, the rocket was disposable. The important bit up top might go on to explore the stars or send a human crew off on their mission, but the booster rocket that lifted the spacecraft out of the atmosphere was always going to be sacrificed for the cause.

But in the 1970s NASA had a wild idea: what if we didn’t smash a brand-new rocket valued at millions of dollars into the ocean every time we wanted to put something in orbit? Instead, they would build a hybrid space vehicle that blended the vertical takeoff and raw power of a rocket with the capabilities of an airplane, allowing it and whatever it was carrying to make a gentle runway landing at the end of its mission. As such, the Space Shuttle was born.

With the benefit of hindsight, we now know the Shuttle wasn’t quite the spaceflight revolution that NASA had hoped for. The age of reusable rockets didn’t truly begin until 2015, when SpaceX landed the first stage of their Falcon 9. To date they’ve repeated the feat nearly 600 times, all the while increasing the reliability and speed of their operations. Today the Falcon 9 is the most prolific launch vehicle in history, and nearly every other rocket in active development is being designed to include some element of reusability.

Most recently, China demonstrated that they could recover their Long March 10B rocket by gently bringing it down into what amounts to a giant butterfly net. While it might seem a bit quaint compared to rockets that land on their tails like something out of a 1950s sci-fi movie, the idea offers considerable promise.

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Spacelab’s Mitra 125 MS

[Ken Shirriff] does some of the most interesting teardowns. This time, he’s looking at a French-built minicomputer called the Mitra 125 MS from around 1980. In particular, it was the computer inside Spacelab, a European lab that could fit in the back of the Space Shuttle.

As you might expect, the computer doesn’t contain a microprocessor. Instead, it is a series of cards and, in this post, [Ken’s] looking at the ALU that allows the computer to perform math operations.

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Ask Hackaday: Where Are All The Fuel Cells?

Given all the incredible technology developed or improved during the Apollo program, it’s impossible to pick out just one piece of hardware that made humanity’s first crewed landing on another celestial body possible. But if you had to make a list of the top ten most important pieces of gear stacked on top of the Saturn V back in 1969, the fuel cell would have to place pretty high up there.

Apollo fuel cell. Credit: James Humphreys

Smaller and lighter than batteries of the era, each of the three alkaline fuel cells (AFCs) used in the Apollo Service Module could produce up to 2,300 watts of power when fed liquid hydrogen and liquid oxygen, the latter of which the spacecraft needed to bring along anyway for its life support system. The best part was, as a byproduct of the reaction, the fuel cells produced drinkable water.

The AFC was about as perfectly suited to human spaceflight as you could get, so when NASA was designing the Space Shuttle a few years later, it’s no surprise that they decided to make them the vehicle’s primary electrical power source. While each Orbiter did have backup batteries for emergency purposes, the fuel cells were responsible for powering the vehicle from a few minutes before launch all the way to landing. There was no Plan B. If an issue came up with the fuel cells, the mission would be cut short and the crew would head back home — an event that actually did happen a few times during the Shuttle’s 30 year career.

This might seem like an incredible amount of faith for NASA to put into such a new technology, but in reality, fuel cells weren’t really all that new even then. The space agency first tested their suitability for crewed spacecraft during the later Gemini missions in 1965, and Francis Thomas Bacon developed the core technology all the way back in 1932.

So one has to ask…if fuel cell technology is nearly 100 years old, and was reliable and capable enough to send astronauts to the Moon back in 1960s, why don’t we see them used more today?

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A Look Inside The Space Shuttle’s First Printer

There was even a day not too long ago when printers appeared to be going the way of the dodo; remember the “paperless office” craze? But then, printer manufacturers invented printers so cheap they could give them away while charging $12,000 a gallon for the ink, and the paperless office suddenly suffered an extinction-level event of its own. You’d think space would be the one place where computer users would be spared the travails of printing, but as [Ken Shirriff] outlines, there were printers aboard the Space Shuttle, and the story behind them is fascinating.

The push for printers in space came from the combined forces of NASA’s love for checklists and the need for astronauts in the early programs to tediously copy them to paper; Apollo 13, anyone? According to [Ken], NASA had always planned for the ability to print on the Shuttle, but when their fancy fax machine wasn’t ready in time, they kludged together an interim solution from a US military teleprinter, the AN/UG-74C. [Ken] got a hold of one of these beasts for a look inside, and it holds some wonders. Based on a Motorola MC6800, the teleprinter sported both a keyboard, a current loop digital interface, and even a rudimentary word processor, none of which were of much use aboard the Shuttle. All that stuff was stripped out, leaving mostly just the spinning 80-character-wide print drum and the array of 80 solenoid-powered hammers, to bang out complete lines of text at a time. To make the printer Shuttle-worthy, a 600-baud frequency-shift keying (FSK) interface was added, which patched into the spaceplane’s comms system.

[Ken] does his usual meticulous analysis of the engineering of this wonderful bit of retro space gear, which you can read all about in the linked article. We hope this portends a video by his merry band of Apollo-centric collaborators, for a look at some delicious 1970s space hardware.

How Different Are SpaceX Thermal Tiles From The Space Shuttle’s?

When SpaceX first showed off the thermal tiles on its Starship spacecraft that should keep it safe when re-entering the Earth’s atmosphere towards the loving embrace of the chopsticks on the launch tower, some similarity to the thermal tiles on NASA’s now retired Space Shuttle Orbiter was hard to miss.

Electron microscope image of the fibrous part of a Starship thermal tile, showing very large fibers. (Credit: Breaking Taps, YouTube)
Electron microscope image of the fibrous part of a Starship thermal tile, showing very large fibers. (Credit: Breaking Taps, YouTube)

Yet how similar are they really? That’s what the [Breaking Taps] channel on YouTube sought to find out, using an eBay-purchased chunk of Shuttle thermal tile along with bits of Starship tiles that washed ashore following the explosive end to the vehicle’s first integrated test last year.

To answer the basic question: the SpaceX engineers responsible for the Starship thermal tiles seem to have done their homework. An analysis of not only the structure of the fibrous material, but also the black IR-blocking coating, shows that the Starship tiles are highly reminiscent of the EATB (introduced in 1996) tiles with TUFI (toughened unipiece fibrous insulation) coatings with added molybdenum disilicide, which were used during the last years of the Shuttle program.

TUFI is less fragile than the older RCG (reaction cured glass) coating, but also heavier, which is why few TUFI tiles were used on the Shuttles due to weight concerns. An oddity with the Starship tiles is that they incorporate many very large fibers, which could be by design, or indicative of something else.

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Hackaday Links: February 4, 2024

Things may not have gone as planned last week for the flying cellphone on Mars, but just because Ingenuity‘s flying career is over doesn’t mean there’s no more work to do. NASA announced this week that it’s going to try a series of “wiggle” maneuvers on Ingenuity‘s rotors, in an attempt to get a better look at the damage to the blade tips and possibly get some clues as to what went wrong. The conjecture at the moment seems to be that a large area of relatively featureless terrain confused the navigation system, which uses down-facing cameras to track terrain features. If the navigation program couldn’t get a bead on exactly how far above the ground it was, it’s possible the copter came in too hard and caused the rotor tips to dig into the regolith. There seems to be some photographic suggestion of that, with what looks like divots in the ground about where you’d expect the rotor tips to dig in, and even scraps of material that look out of place and seem to be about the same color as the rotor blades. All this remains to be seen, of course, and we’re sure that NASA and JPL are poring over all available data to piece together what happened. As much as we hate to say goodbye to Ingenuity, we eagerly await the post-mortem.

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That Time NASA Built A Tiny Tank To Pop Shuttle Tires

The Space Shuttle has often been called the most complex pieces of machinery ever built, an underhanded compliment if there ever was one. But it’s a claim not strictly limited to the final spacecraft. With a project as far ahead of the technological curve as the Shuttle was in the 1970s, nearly every component and system of the legendary spaceplane required extensive research and development to realize.

A case in point is that the speed and mass of the Shuttle at touchdown required tires that could survive forces far beyond that of a normal airplane. Pumped up to an incredible 350 psi, the space agency estimated each tire had the explosive potential of two and one-half sticks of dynamite. So while testing landing gear upgrades in the 1990s, they cobbled together an RC tank that could “defuse” a damaged tire remotely by drilling holes into it and letting off the pressure. Continue reading “That Time NASA Built A Tiny Tank To Pop Shuttle Tires”