A red-painted Launch Umbilical Tower (LUT) was the Saturn V rocket's constant companion from the moment technicians lowered the rocket's 138-foot-tall S-IC first stage into place beside it within a Vertical Assembly Building (VAB) high bay until shortly after the the S-IC's engines ignited on one of the twin Launch Complex (LC) 39 pads. The nine servicing arms linking the 398-foot-tall LUT to the 363-foot-tall Saturn V would retract or swing out of the way; then, between 1.4 and 9.4 seconds after liftoff, the rocket would perform a LUT clearance yaw maneuver, its five F-1 engines bathing the launch pad in flame. After that, the LUT would stand alone, awaiting transport back to the VAB and the arrival of a new Saturn V.
By late 1969, with the Apollo 11 and 12 lunar landing missions successfully accomplished, it had become clear that only a few more Saturn V rockets would depart LC 39 for the moon. The $25-billion Apollo Program had achieved its goal of humbling the Soviet Union, and many outside of space industry and the fledgling planetary science community saw little cause to continue it.
Meanwhile, NASA Administrator Thomas Paine aspired to replace the moon program with a large Earth-orbiting space station (a "Space Base") serviced by a fully reusable crew rotation and logistics resupply spacecraft (a "Space Shuttle"). By the beginning of the 1980s these would, it was hoped, become elements in an Integrated Program Plan that would lead to a manned lunar base and men on Mars.
The Nixon White House would have none of it, however. By the time Congress passed the $3.75-billion Fiscal Year 1970 NASA budget - the lowest since 1962, the first year of the Apollo build-up - space planners had begun to look for tactics that they could use to achieve ambitious goals while spreading out costs. One of these was "series development."
As applied to the Space Shuttle, series development could occur in either of two ways. First, the Space Shuttle's fully reusable manned Booster could be developed and brought into service, then work could begin on its fully reusable manned Orbiter. Until the Orbiter became available, the suborbital Booster would lift off from Cape Kennedy, Florida, carrying an expendable upper stage based on an existing stage design (perhaps the Saturn V S-IVB third stage) and an unmanned payload. The upper stage would ignite high over the Atlantic, boosting the payload to Earth orbit and beyond. The astronauts, meanwhile, would pilot the Booster back to Cape Kennedy, where it would be refurbished and flown again.
More attractive to planners who were eager to see astronauts continue to fly into orbit (that is, almost all of them) was development of the Shuttle Orbiter followed by development of the Booster. In this "Orbiter first" scenario, an expendable Saturn V S-IC first stage would stand in for the Booster during early Shuttle flights.
On the last day of 1969, C. Eley, an engineer with Bellcomm, NASA's Washington, DC-based planning contractor, published a memorandum in which he examined how the Orbiter/S-IC combination might be serviced and launched using a LUT "without extensive modifications." Eley assumed that the S-IC would fly virtually unmodified (apart from a 10-foot-long streamlined shroud linking its dome-shaped top to the Orbiter's tail) and that the Orbiter would measure 183 feet long. This would make the combination 331 feet tall, or 32 feet shorter than the Saturn V.
Eley found that LUT servicing arms 1, 2, 4, 8, and 9 would remain useful. He recommended that arms 3, 5, 6, and 7 be removed and stored to prevent them from becoming damaged (implying, perhaps, that the LUT might be restored to its original form and purpose - that is, to launch Saturn V rockets - at a later date). Arms 1 and 2, which would service the S-IC, would remain completely unchanged.
All Orbiter servicing - for example, propellants loading - would occur via arm 4, close by the Orbiter's tail. Arm 8 would provide services - for example, cooling - to the payload in the Orbiter's cargo bay, but would not enable access to the payload because the orbiter's back, where the bay doors would be located, would face away from the LUT on the pad. Ealy assumed that the Mobile Servicing Structure used on the launch pad to reach parts of the Saturn V located away from the LUT arms would not be used with the Orbiter/S-IC. He suggested that a special arm be added to the LUT if payload access on the launch pad were judged to be necessary. Arm 9 would reach out from the LUT to cap the Orbiter's nose, permitting access to the Orbiter crew cabin.
Eley then examined the Orbiter/S-IC stage's probable launch rate. He assumed that the Orbiter would include an "autonomous checkout capability" that would dramatically reduce the time it would need to spend on the launch pad prior to launch. Assuming that all three Apollo LUTs would be modified for Orbiter/S-IC launches, that a LUT could be refurbished within 15 days of a launch, and that pre-launch Orbiter/S-IC preparations on the launch pad would last only five to 10 days, then more than 40 Orbiter/S-IC launches could take place in a year. If, on the other hand, only a single modified LUT, a 30-day LUT refurbishment period, and an on-pad preparation time no less than 30 days were assumed, then only six or seven Orbiter/S-IC flights could occur in a year.
A little more than two years after Eley completed his memorandum, budget shortfalls forced NASA to postpone Space Station development until after the Shuttle flew - another example of series development. Two of the Apollo-era LUTs were put to use in the Space Shuttle Program, though not as Eley envisioned. NASA partially dismantled them, reducing their height to 247 feet (not counting a new 100-foot-tall lightning mast), then permanently mounted them on the two LC 39 launch pads. The third LUT was dismantled sometime after 1982 and scrapped in 2004 after its peeling red paint was judged to be an environmental hazard.
Reference:
Feasibility of Shuttle (Orbiter)/S-IC Launches at LC-39 - Case 320, C. Eley, Bellcomm, Inc., 31 December 1969.
Beyond Apollo chronicles space history through missions and programs that didn't happen.
