It is easy to become overwhelmed by the vastness and complexity of outer space, and many have a newfound appreciation for the immense scale of what has been achieved by NASA throughout its existence. From the first American in space to the first rover on Mars, NASA has pushed boundaries and achieved milestones which many never dreamt possible.
However, for every triumph that NASA can look back on, there are many concepts, initiatives and plans which, for various reasons, never got the chance to take shape. Whether due to technological improbability, prohibitive cost, or simply an element of timeliness, these seven now-defunct projects represent a unique insight into the changing landscapes of space exploration over the course of more than sixty years.
The first of these unrealised dreams was the AstraGate transport system, proposed by the TransAstronautics Corporation in 2018 and 2019, to create a renewable energy and momentum transfer system between Earth and the Moon. The concept proved too much for NASA to pursue, due to both its scale and the materials required, so it was ultimately shelved.
The second concept was the ambitious Mobile Geological Laboratory, or MOLAB, which was designed as a temporary habitat and exploration platform to accompany NASA’s eventual manned missions to the Moon. Eventually employed by the US Geological Survey, the MOLAB weighed a hefty 8,200 pounds and was too cumbersome to make it to space.
Thirdly, NASA ran an initiative from 1955 to 1973 to create a nuclear rocket for use in extended missions and interplanetary exploration. Named the Nuclear Engine for Rocket Vehicle Applications (NERVA), the project saw the creation of several test engines around 1966, but was eventually aborted before any could be launched.
A fourth consideration was the creation of a number of off-world colonies, conceptualised by experts and artists in a series of 1975 studies for NASA. These space habitats were imagined to suggest traditional homes, monorails, trees, grass, bodies of water and agriculture, and include a capacity for up to 10,000 people. However, the technologies necessary remained out of reach, preventing this concept from being realised until much later.
The fifth proposal was known as Project Longshot, and was an effort to have a space probe explore Alpha Centauri, the star system closest to our Sun some 4.37 light-years away. Though tested on the ground, the atomic-powered craft remained out of reach.
The sixth project was the X-34, an effort to take the Shuttle program to the next level by developing a reusable vehicle to manage orbital experiments. The X-34 progressed to the point of near-completion in 2001, but budget constraints ultimately put an end to the project.
Lastly, the Titan Mare Explorer (TiME) was proposed by Proxemy Research in 2009, as the first probe to explore Ligeia Mare, one of Titan’s methane oceans. It narrowly missed selection for NASA’s Discovery program, though its aspirations were eventually matched in the Dragonfly mission, due for launch in 2027.
Sadly, these seven projects demonstrate a cross-section of concepts that, while not unfeasible, could not be pursued by NASA due to one of the above constraints, or a combination of them. With technology rapidly evolving, we can hope that some of these dreams may one day realise themselves, and that the scope of space exploration and colonisation will continue to expand beyond what was once thought possible.
For those eager to learn more, there is a plethora of interactive resources and archives available which provide a more in-depth look at many of these projects, as well as articles and videos going over the background and reality of space exploration today. What is certain is that the history of space exploration continues to provide a vivid reminder of human endeavour and the ambition to reach the furthest reaches of our universe.