Seger shrugged. “We may have built the thing, but we haven’t yet spent the money to make it fly.”

“We can’t go to the fucking Moon,” Chuck Jones said. “We’re still waiting on the J-2S.” Lunar-orbital workshops were planned, but a few years down the road, following extensive modifications to the S-IVB: the upgraded J-2S main engine, additional payload capacity, a self-ullaging system, electrical heating blankets and Mylar insulation, additional batteries, upgraded electronics… “The fucking S-IVB doesn’t have the power to inject itself into lunar orbit.”

“No, it doesn’t. But it doesn’t need to. Look at this.” Seger had a glossy presentation on his desk; he handed them copies.

Stone looked quickly. It was a summary of an old McDonnell Douglas study called LASSO — Lunar Applications of a Spent S-IVB Stage (Orbital). It showed how Saturn components could be used to establish lunar orbit workshops of varying complexity and weight. It was full of cutaway isometric diagrams and color pictures and big bold bullet-point blocks of text, and — naturally, as it came from the manufacturers of the S-IVB — it was relentlessly optimistic: some of the projected dates were already in the past.

“Look at Baseline 1.” Seger pointed to sections of the presentation. “That shows how we can take a workshop to lunar orbit without the J-2S upgrade, or any of the rest of it…”

A Saturn V would be launched looking superficially like those for the Apollo landing flights. But instead of a Lunar Module, the booster would carry an airlock module, fixed to the front of the third stage.

The S-IVB would send the spacecraft toward the Moon. Just like the landing missions. But, once exhausted, the third stage wouldn’t be discarded. The Apollo would decouple and dock with the empty stage via the airlock adapter. The stack would follow a long, lower-energy trajectory to the Moon: a day and a half more than the three-day landing flights. Then the Apollo Service Module’s main engine would be used to brake the whole stack into lunar orbit.

The empty stage would have the same weight and dynamic characteristics, roughly, as a loaded LM. So an Apollo would indeed be able to deliver it to lunar orbit. The only modifications needed for the S-IVB would be the usual passivation and neutralization kit — equipment to turn the stage from a dry fuel can into a working station — and equipment brackets and pallets. Enough supplies could be carried for a four-week stay in lunar orbit, and the station would be refurbished for later crews.

As he read, Stone began to see the feasibility of it. It could, he realized, be done. But…

“Why?”

Jones looked up from his own reading; Seger fixed Stone with a glare.

“Why what?”