18 November 2015

Series Development: A 1969 Plan to Merge Shuttle and Saturn V to Spread Out Space Program Cost

Apollo 4, the first Saturn V rocket to fly, departs the Vertical Assembly Building bound for Pad 39A, 26 August 1967. LUT 1 rides beside the rocket on a crawler-transporter; a second LUT in the background awaits its first launch. Image credit: NASA
A red-painted Launch Umbilical Tower (LUT) was the Saturn V'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 S-IC's engines ignited on one of the twin Launch Complex (LC) 39 pads. At the moment of liftoff, 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 atop one of Kennedy Space Center's two enormous crawler-transporters and assembly 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 serviced by a fully reusable crew rotation and logistics resupply spacecraft (a "Space Shuttle"). A fully functional 6-man or 12-man core station would reach Earth orbit on a Saturn V rocket; later, Saturn V rockets would launch multiple large Space Station modules which would be brought together to form a 50- or 100-man "Space Base." 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 surface base and men on Mars by 1990.

The Nixon White House and the Congress 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 Program build-up - space planners had begun to seek tactics that they could use to achieve ambitious goals while spreading out costs. One of those tactics was "series development."

Booster-first development: in this artist concept, a reusable Space Shuttle Booster carries an expendable Saturn S-IVB stage and payload to the edge of space. Image credit: NASA
As applied to the Space Shuttle, series development could take either of two forms. In the first, the Space Shuttle's fully reusable piloted Booster would be developed and brought into service, then development work would begin on its fully reusable piloted Orbiter.

Until the Orbiter became available, the suborbital Booster would lift off from Cape Kennedy, Florida, carrying on its back an unmanned payload attached to an expendable upper stage based on an existing stage design - the Saturn V S-IVB third stage was one attractive candidate. The upper stage would ignite high over the Atlantic, boosting the payload to Earth orbit - or beyond. The astronauts, meanwhile, would pilot the Booster back to a runway at Cape Kennedy, where it would be refurbished, mated with a new upper stage and payload, and flown again.

Three-stage Saturn V rocket with Apollo spacecraft payload on top, Orbiter with Saturn S-IC first stage, and LUT with nine Apollo Saturn V servicing arms. Image credit: Bellcomm/NASA
More attractive to space planners 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 would stand in for the Booster during the first few years of 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 [and expensive] 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 Apollo Saturn V.

Eley found that LUT servicing arms 1, 2, 4, 8, and 9 would remain useful for Orbiter/S-IC pre-launch servicing. 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, launching Saturn V rockets - at some point). Arms 1 and 2, which would service the S-IC stage, would remain completely unchanged in form and function.

Orbiter-first development: a reusable Shuttle Orbiter with an expendable Saturn S-IC first stage stands beside a modified LUT. Image credit: Bellcomm/NASA
All Orbiter servicing - for example, propellants loading - would employ arm 4, close by the Orbiter's tail. Arm 8 would provide services - for example, cooling - to the payload in the Orbiter's payload bay, but would not enable access to the payload because the Orbiter's top side, where its payload bay doors would be located, would face away from the LUT on the pad. Eley assumed that the Mobile Servicing Structure used during Apollo to reach parts of the Saturn V located out of reach of 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 its crew cabin.

Eley then examined the probable launch rate of the Orbiter/S-IC stage Space Shuttle. He made three assumptions about the Orbiter and the LUT: that the Orbiter would include an "autonomous checkout capability" that would help to reduce to from five to 10 days time spent on the launch pad prior to launch; that all three Apollo LUTs would be modified for Orbiter/S-IC launches; and that experience would prove that a LUT could be fully refurbished within 15 days of taking part in a launch.

If these assumptions were shown to be correct, Eley found, 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 per 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. Shuttle Orbiters, not Saturn V rockets, would launch NASA's future Space Station. The Station would be launched in pieces in the Shuttle Orbiter payload bay and assembled in Earth orbit.

Two of the Apollo 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 80-foot-tall lightning mast), then permanently mounted them on the two LC 39 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.

Sources

"Feasibility of Shuttle (Orbiter)/S-IC Launches at LC-39 - Case 320," C. Eley, Bellcomm, Inc., 31 December 1969

Welcome to the Save the LUT Campaign - http://www.savethelut.org/ (link accessed 19 November 2015)

More Information

What if an Apollo Saturn Rocket Exploded on the Launch Pad? (1965)

An Alternate Station-Shuttle Evolution: The Spirit of '76 (1970)

McDonnell Douglas Phase B Space Station (1970)

Where to Launch and Land the Space Shuttle? (1971-1972)

5 comments:

  1. Always thought that Shuttle-Saturn was the way to go. So much infrastructure could be reused, and imagine what a modern F-1 engine that was the product of nearly 50 years of use, design, tinkering, etc could do.

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    1. I think Shuttle-Saturn might've come along in the 1990s as the Apollo Program evolved, though probably not with such a big Orbiter. I think eventually the CSM would have constrained the program, so NASA would have pitched for something better. Same with Skylab-type stations. Eventually they would have become restrictive. I can imagine an MDA with berthing ports for big modules and rearranged solar arrays.

      dsfp

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  2. Here's a study of what a modernized F-1 engine might be like: http://arstechnica.com/science/2013/04/new-f-1b-rocket-engine-upgrades-apollo-era-deisgn-with-1-8m-lbs-of-thrust/2/

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    1. There's some really interesting stuff there. Thanks, Phil.

      dsfp

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    2. You're welcome, sir.

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