What if NASA chose a different plan for spaceflight after the Apollo program?
Faced with tighter budgets after the completion of the Apollo program, NASA outlined a plan that would establish a crewed space station in low orbit, while also using a small, reusable logistics vehicle to support it. An orbiter with large cargo area that used an external propellent tank was proposed, but this idea was discarded when spiraling cost projections and the maintenance schedule for such a vehicle would be prohibitive. The Air Force was lukewarm to such an orbiter, but had lately come around to the idea of getting a lifting body spaceplane back into development. The plan presented for a post-Apollo space program was a cheap, reusable lifting body that could ferry crew and cargo to a space station, while riding a powerful booster that used Saturn technology, but within the reduced budget. With this approach, NASA could develop the shuttle, a space station, and a new launch vehicle, rather than just the shuttle alone. This plan was approved and put into motion in 1972. Out of the submitted designs, Grumman was chosen to develop this new space shuttle.
The new launch vehicle was a smaller, stripped down Saturn V variant with a single F1 engine as the core stage. Development costs were kept in check with this approach, and the Saturn MO3 began static firing tests.
NASA also decided to return to improving upon the SkyLab design to save money. At this point SkyLab had faced several problems during its launch, and engineers wanted to take the lessons learned and apply it to a new, improved version. To this end, SkyLab B began modifications for later use, to be put into orbit by the last remaining Saturn V in stock.
Last but not least, a reusable, light, cheap, shuttle - dubbed at first the X-22. Testing flights were conducted, and a final wing design made the vehicle quite robust and easy to land. Two versions were developed - a crewed version that could bring 4 astronauts to the space station and back, and a cargo version with a small cargo bay that could be flown autonomously if needed. NASA leaders were excited over the estimates of the maintenance schedule and cost of the vehicle, which could be refurbished and put back into service in less than a month. While testing continued on the design and the 48-7S 'Spark' engine that would power it, the Apollo Program came to a close, and NASA had no vehicle to save the ill-fated SkyLab. Still, NASA was an optimistic enviroment about the future.
