Illustration of a Gemini B reentry vehicle separating from the Manned Orbiting Laboratory (MOL). (Source: US Air Force)

The Advanced Project Gemini Concepts That Could Have Been

August 29, 2025 by Maya Posch 1 Comment

Looking back on the trajectory leading to Project Apollo and the resulting Moon missions, one can be forgiven for thinking that this was a strict and well-defined plan that was being executed, especially considering the absolute time crunch. The reality is that much of this trajectory was in flux, with the earlier Project Gemini seeing developments towards supplying manned space stations and even its own Moon missions. [Spaceflight Histories] recently examined some of these Advanced Gemini concepts that never came to pass.

In retrospect, some of these seem like an obvious evolution of the program. Given both NASA and the US Air Force’s interest in space stations at the time, the fact that a up-sized “Big Gemini” was proposed as a resupply craft makes sense. Not to be confused with the Gemini B, which was a version of the spacecraft that featured an attached laboratory module. Other concepts, like the paraglider landing feature, were found to be too complex and failure prone.

The circumlunar, lunar landing and Apollo rescue concepts were decidedly more ambitious and included a range of alternatives to the Project Apollo missions, which were anything but certain especially after the Apollo 1 disaster. Although little of Advanced Gemini made it even into a prototype stage, it’s still a fascinating glimpse at an alternate reality.

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Ask Hackaday: Where Are All The Fuel Cells?

August 21, 2025 by Tom Nardi 56 Comments

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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Hackaday Links: August 10, 2025

August 10, 2025 by Dan Maloney 11 Comments

We lost a true legend this week with the passing of NASA astronaut Jim Lovell at the ripe old age of 97. Lovell commanded the ill-fated Apollo 13 mission back in 1970, and along with crewmates Jack Swigert and Fred Haise — along with just about every person working at or for NASA — he managed to guide the mortally wounded Odyssey command module safely back home. While he’s rightly remembered for the heroics on 13, it was far from his first space rodeo. Lovell already had two Gemini missions under his belt before Apollo came along, including the grueling Gemini 7, where he and Frank Borman undertook the first long-duration space mission, proving that two men stuffed into a Volkswagen-sized cockpit could avoid killing each other for at least two weeks.

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The Apollo–Soyuz Legacy Lives On, Fifty Years Later

July 17, 2025 by Tom Nardi 11 Comments

On this date in 1975, a Soviet and an American shook hands. Even for the time period, this wouldn’t have been a big deal if it wasn’t for the fact that it happened approximately 220 kilometers (136 miles) over the surface of the Earth.

Although their spacecraft actually launched a few days earlier on the 15th, today marks 50 years since American astronauts Thomas Stafford, Vance Brand, and Donald “Deke” Slayton docked their Apollo spacecraft to a specifically modified Soyuz crewed by Cosmonauts Alexei Leonov and Valery Kubasov. The two craft were connected for nearly two days, during which time the combined crew was able to freely move between them. The conducted scientific experiments, exchanged flags, and ate shared meals together.

Politically, this very public display of goodwill between the Soviet Union and the United States helped ease geopolitical tensions. On a technical level, it not only demonstrated a number of firsts, but marked a new era of international cooperation in space. While the Space Race saw the two counties approach spaceflight as a competition, from this point on, it would largely be treated as a collaborative endeavour.

The Apollo–Soyuz Test Project lead directly to the Shuttle–Mir missions of the 1990s, which in turn was a stepping stone towards the International Space Station. Not just because that handshake back in 1975 helped establish a spirit of cooperation between the two space-fairing nations, but because it introduced a piece of equipment that’s still being used five decades later — the Androgynous Peripheral Attach System (APAS) docking system.

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History Of Forgotten Moon Bases

June 16, 2025 by Al Williams 37 Comments

If you were alive when 2001: A Space Odyssey was in theaters, you might have thought it didn’t really go far enough. After all, in 1958, the US launched its first satellite. The first US astronaut went up in 1961. Eight years later, Armstrong put a boot on the moon’s surface. That was a lot of progress for 11 years. The movie came out in 1968, so what would happen in 33 years? Turns out, not as much as you would have guessed back then. [The History Guy] takes us through a trip of what could have been if progress had marched on after those first few moon landings. You can watch the video below.

The story picks up way before NASA. Each of the US military branches felt like it should take the lead on space technology. Sputnik changed everything and spawned both ARPA and NASA. The Air Force, though, had an entire space program in development, and many of the astronauts for that program became NASA astronauts.

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Repairing A Real (and Broken) Apollo-era DSKY

January 14, 2025 by Maya Posch 6 Comments

Presumably the same DSKY unit installed in the simulator at MIT.

The Display/Keyboard unit – DSKY for short – is the primary way that Apollo-era astronauts communicated with the onboard computers. Not all DSKYs ended up in space, however, with the MIT hosting a simulator that features one of these units. Unfortunately the unit that ended up at [CuriousMarc]’s lab had seen better days, with the assumption being that it was the same DSKY that was installed in a photo of the old simulator. In addition to the busted EL display and two (improper) replacement keys, the insides show signs of damaged modules and possibly worse.

Without bothering to hook the unit up to the (previously restored) guidance computer, a full teardown was begun to assess the full extent of the damage. Considering that the DSKY uses latching relays for memory and two modules were ominously marked as being defective, this made for a tense wait as the unit was disassembled.

Fortunately making new DSKY-style EL displays has first been replicated in 2019, meaning that a replacement is possible. Perhaps surprisingly, the busted display still fires up in the test rig, as a testament to how robust the technology is. At the end of the teardown, the assessment is that the unit can be restored to its original condition, which will be done in the upcoming videos in this series.

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Apollo-era PCB Reverse Engineering To KiCad

November 25, 2024 by Chris Lott 24 Comments

Earlier this year [Skyhawkson] got ahold of an Apollo-era printed circuit board which he believes was used in a NASA test stand. He took high quality photos of both sides of the board and superimposed them atop each other. After digging into a few obsolete parts from the 1960s, he was able to trace out the connections. I ran across the project just after making schematics for the Supercon badge and petal matrix. Being on a roll, I decided to take [Skyhawkson]’s work as a starting point and create KiCad schematics. Hopefully we can figure out what this circuit board does along the way.

The board is pretty simple: