History is a set of lies agreed upon. – Napoleon Bonaparte
Now that the Space Shuttle’s been retired, we’ve witnessed nearly universal agreement within the space commentariat on its legacy: Failure. Take your pick of descriptors – a mistake, a bad design, “the end of an error,” the wrong path, a death-trap, and/or “Nixon’s destruction of Apollo.” It doesn’t matter whence this criticism comes; the same words and phrases are recited again and again. Are these denunciations independent convergence on the truth or simply echoes in a canyon?
In part, it’s the image of the Space Shuttle that suffers in comparison to its immediate predecessor, Apollo. The Saturn V was magnificent – a gleaming white monument pointing to the stars, a Teutonic beauty rising above Earth, carried aloft on a glorious blinding pillar of orange flame while thunderous super-bass, low frequency pounding of engines vibrated inside your chest up to five miles away. The Apollo spacecraft took people to the Moon, hundreds of thousands miles beyond low Earth orbit. From that lofty perch, we saw the full globe of the lovely blue-and-white planet Earth, hanging before us like a masterpiece in the Louvre. For space buffs, the Apollo program was a spectacle to remember and savor.
Contrast that vision with the Space Shuttle – squat and ugly, the vehicle defaced Pad 39A by its ignoble presence. It was a kludged-together conglomeration – an airplane standing on its tail, overwhelmed by the presence of the big, ugly orange hulk of the ET and two giant Roman candles strapped to its side. When it lit, you held your breath, waiting for the inevitable catastrophic fireball explosion. Then by some miracle it reached orbit, but no further. What a disappointment – a thrown-together launch vehicle that only reached low Earth orbit (barely). It even had to open its cargo bay doors to radiate internal heat so the crew could remain aloft. The Shuttle ugly duckling suffered greatly in comparison to the beautiful Saturn V swan.
Why should it matter that Shuttle is gone? What have we really lost? In fact, just about everything. Outside of leasing seats on regularly flying Russian Soyuz spacecraft, America has no way to get humans to and from space. We cannot launch large replacement parts for the International Space Station (good thing that it’s fully assembled; let’s hope it does not develop any serious difficulties that require replacement of any of the major pieces). We no longer have the ability to access and service the Hubble Space Telescope, or any other satellite for that matter. We will remain without this capability even after the new Orion spacecraft becomes operational. The Shuttle stack had a throw weight of more than 100 tons; nothing in the world’s stable of launch vehicles remotely approaches that capability.
The Shuttle program came about because NASA was looking for a path to make spaceflight affordable and routine. Although proven, Apollo was simply too expensive to continue. Parts of the Saturn V were (literally) hand-made. Recently I’ve been reading commentary about the Shuttle program that’s appeared in the last few years and certain tropes repeatedly appear. In this piece, I want to examine and address some of them. I reserve the right to revisit this topic later for more rumination on other issues.
One canard often mentioned in the Apollo-Shuttle comparison is that for what the Shuttle program cost, we could have launched dozens of Saturn Vs. Perhaps, but what would we have launched? The Shuttle payload was about 25 tons; Saturn V could carry 120 tons. If we’d flown the same manifest, Saturn would have wasted 4/5 of its capacity on each launch. Of course, we could have combined some payloads – if they were ready at the right time and they all needed to be delivered to the same orbit.
It’s often alleged that Nixon cancelled the Apollo program because it was a Kennedy initiative. In fact, it was Lyndon Johnson who shut down the Saturn V production line in 1968 to finance the war in Vietnam and expand entitlements. True enough, the last three Apollo missions to the Moon were cancelled, but it was NASA that wanted that. The Apollo program managers thought that having accomplished their primary goal (“man-Moon-decade”), they were simply tempting fate (and a possible catastrophic loss of crew) to continue the program. As a lunar scientist, I am more grateful that we got the six landings that we did than resentful that the last three were cancelled.
Nixon was actually a huge supporter of human spaceflight. At a time of great social upheaval and turmoil, Nixon thought that the space program was a positive, forward-looking activity that could help counter the negativity then prevalent in America. However, as both a plain-cloth Republican and a political realist, he realized that there was no support for the expenditures that a human Mars mission (as his Vice-President Spiro Agnew advocated) would require. Nixon wanted a space program that we could afford. He also recognized the geopolitical importance of not allowing the Soviet Union to become the only world power with a human spaceflight program. Nixon’s judgment was that a program that could hold the line at less than one percent of the federal budget would be sustainable on a long-term basis, a supposition that the subsequent thirty-year history of the civil space program has shown to be correct.
It was on these terms that NASA began to examine possible Shuttle configurations. It was not simply a matter of being given a number and designing a program to fit that number. Cost is always a concern in any big technical project. In this case, the issue was what kind of human space program could we have given such a level of support.
Early design sketches for a space shuttle included a two-stage, fully reusable vehicle. That led to the legend that it was this obviously superior design NASA wanted but was forced by the budget bean counters to build the lower cost, partly reusable alternative. In fact, there were serious issues with the fully reusable design; many engineers thought that in technical terms, it was just a bridge too far in 1970 (and still is in 2013). According to Bob Thompson, Shuttle Program Manager during this era, it probably could not have been made to work. The decision to adopt a partly reusable design probably saved the space program from inevitable failure and subsequent collapse.
Also held up for criticism is Shuttle’s delta wing. It is often claimed that the large delta wing configuration of the Shuttle was imposed by military requirements. If Shuttle had been launched into a polar orbit, after one revolution the launch (and landing) site would no longer be under the Shuttle groundtrack. Delta wings gave the Shuttle the large cross-range capability (more than 1000 km) it needed to return to base quickly in launch abort scenarios. The massive triangularly shaped Shuttle wings reduced the payload capacity of the vehicle, but delta wing vehicles are more aerodynamically stable in the various velocity regimes through which the Shuttle traveled during re-entry from orbit to landing. If the Shuttle wing design was an “imposition,” it was a beneficial one for the ultimate design that emerged.
The sizing of the Shuttle payload bay is also held to be another military imposition. Supposedly, the 15 by 60 foot cargo bay was sized specifically to accommodate launching the then-planned reconnaissance satellites needed by the military. However, NASA also wanted a big cargo bay. They intended to eventually build a space station in low Earth orbit and Shuttle was sized in accordance with its anticipated needs. If the Shuttle stack had been much larger than it was, it might never have gotten off the ground; it certainly would not have fit through the doors of the VAB at the Cape, necessitating extensive reconstruction. If it were much smaller, a single vehicle would no longer serve all of the space program’s needs. Like Goldilocks, a “just right” Shuttle was built to satisfy all of the program requirements, as they were then understood.
Part of the great disappointment with Shuttle was that it cost more to operate than planned. Some pre-program economic studies showed that if you could fly the Shuttle 50 times a year, it might actually make money. No one seriously thought that we would ever achieve this number. Klaus Heiss, the man who did this analysis, once told me that the study was primarily an academic exercise, designed to compare the economics of a Shuttle with then-existing expendable launch vehicles. (Klaus also demonstrated that a partly reusable vehicle was better economically than a fully reusable one.) A reusable space vehicle had never been built and serious technical difficulties arose during its development. The complex thermal protection system (tiles) is one example. Upon each return to Earth, the Shuttle had to dissipate its enormous orbital kinetic energy as heat. Finding a material strong and light enough to provide this protection was extremely difficult and the system turned out to be more maintenance intensive than had been hoped.
Despite these difficulties and a lingering resentment about its origin and appearance, the Space Shuttle flew 133 successful missions, delivering over 3.5 million pounds of payload to space, including nearly the entire mass of the largest spacecraft made to date – the International Space Station. More than 350 people have traveled to space on the Shuttle. Over the course of its thirty-year history, the Shuttle program demonstrated the value of on-obit assembly, in-space repair, and maintenance of vehicles by people and machines working together. Such a step-by-step, extensible series of operations and experience must continue if we intend to pursue and successfully secure humanity’s long-term future in space.