Tuesday, March 2, 2010

Why Bush Cancelled the Space Shuttle


President George W. Bush announces his Vision for Space Exploration on January 14, 2004. His proposal included the end of the Space Shuttle program in 2010.



The Shuttle's chief purpose over the next several years will be to help finish assembly of the International Space Station. In 2010, the Space Shuttle — after nearly 30 years of duty — will be retired from service.

— President George W. Bush
January 14, 2004

Many falsehoods and misconceptions are being circulated around the Space Coast in the wake of the Obama Administration's release of its proposed 2011 NASA budget.

One common fallacy I've seen and heard is that "Obama cancelled the Space Shuttle."

No, he didn't.

The Bush Administration cancelled the Space Shuttle program in the wake of the Columbia accident.

On January 14, 2004, President Bush gave a speech in which he announced "a new focus and vision for future exploration."

The elements of that speech were:

  • Complete the assembly of the International Space Station (ISS) by 2010, then retire the Shuttle from service.
  • "... Develop and test a new spacecraft, the Crew Exploration Vehicle, by 2008, and to conduct the first manned mission no later than 2014." The CEV would be used to ferry astronauts first to the ISS, and later to "beyond our orbit to other worlds."
  • "... Return to the moon by 2020, as the launching point for missions beyond."
  • "With the experience and knowledge gained on the moon, we will then be ready to take the next steps of space exploration: human missions to Mars and to worlds beyond."

Click here to read the entire Vision for Space Exploration proposal.

The program to execute Bush's proposal eventually became known as Constellation. We'll discuss Constellation's fate in another blog entry.

In any case, it's clear that the process for shutting down Shuttle began under the Bush administration. Obama's first budget, for fiscal year 2010, continued the shutdown.

Why was Shuttle cancelled?

Some people assume it's because the Shuttle is "old" but that's not the case.

"Shuttle" refers to the entire Space Transportation System — the Orbiter, the orange External Tank and the two white Solid Rocket Boosters. The SRBs fall back into the Atlantic and are recovered for reuse. The ET is destroyed as it falls back into the atmosphere. So age is an issue only with the orbiters.

Each orbiter was designed for a projected lifespan of 100 launches. They are regularly refurbished. Aging is not an issue.

Bush cancelled Shuttle because its design is considered unsafe.

The fundamental problem is that the orbiter is mounted on the side, where it's exposed to nearby flame and falling debris. Earlier manned launch vehicles had the crew compartment atop the rocket, which could be jettisoned using an abort mechanism. Shuttle has no abort capability during the first two minutes of launch, until the SRBs detach, at which point the orbiter can theoretically glide to a landing at an abort site — a theory that's never been tested.

Fourteen astronauts have been lost during the Shuttle program. Seven died when Challenger was destroyed 73 seconds into the launch of Mission STS 51-L on January 28, 1986. Another seven died on February 1, 2003, when Columbia broke up over Texas as it returned from its science mission.

In retrospect, both accidents were preventable.


Challenger launches on January 28, 1986.

The Presidential Commission on the Space Shuttle Challenger accident, commonly known as the Rogers Commission after its chairman, found that a solid rocket booster seal leak exploded the external tank, taking Challenger with it. "The failure was due to a faulty design unacceptably sensitive to a number of factors," the Commission's report concluded. "These factors were the effects of temperature, physical dimensions, the character of materials, the effects of reusability, processing, and the reaction of the joint to dynamic loading."

The Rogers Commission also cited faulty decision-making by management.

The decision to launch the Challenger was flawed. Those who made that decision were unaware of the recent history of problems concerning the O-rings and the joint and were unaware of the initial written recommendation of the contractor advising against the launch at temperatures below 53 degrees Fahrenheit and the continuing opposition of the engineers at Thiokol after the management reversed its position.

The Commission chose not to address the issue of Shuttle's fundamental design.

The events of flight 51-L dramatically illustrated the dangers of the first stage of a Space Shuttle ascent. The accident also focused attention on the issues of Orbiter abort capabilities and crew escape. Of particular concern to the Commission are the current abort capabilities, options to improve those capabilities, options for crew escape and the performance of the range safety system.

It is not the Commission's intent to second-guess the Space Shuttle design or try to depict escape provisions that might have saved the 51-L crew.


The Shuttle system had been flying for less than five years. The nation had made an enormous investment in the program. Had the Rogers Commission called out Shuttle's fundamental design flaw, the President and Congress would have been left with the delicate task of convincing Americans to resume launches of an inherently unsafe system.

And so Shuttle flew again.

STS-107 launched on January 16, 2003. A large piece of hand-crafted insulating foam came off its external tank and struck the left wing of Columbia 82 seconds after launch, creating a breach in its leading edge. When the orbiter re-entered the atmosphere on February 1, superheated air penetrated the cavity and destroyed the left wing from within, eventually causing Columbia to break up at 10,000 MPH as it sped over Texas.

Another investigating commission was formed, called the Columbia Accident Investigation Board, or CAIB.

Unlike their predecessor, the CAIB members didn't pull their punches on Shuttle's fundamental design flaw. In Chapter 1 of their report, they outlined the political compromises made to satisfy all those with a stake in designing the sequel spacecraft to Apollo, including the military.

It is the Board's view that, in retrospect, the increased complexity of a Shuttle designed to be all things to all people created inherently greater risks than if more realistic technical goals had been set at the start. Designing a reusable spacecraft that is also cost-effective is a daunting engineering challenge; doing so on a tightly constrained budget is even more difficult. Nevertheless, the remarkable system we have today is a reflection of the tremendous engineering expertise and dedication of the workforce that designed and built the Space Shuttle within the constraints it was given.

In the end, the greatest compromise NASA made was not so much with any particular element of the technical design, but rather with the premise of the vehicle itself. NASA promised it could develop a Shuttle that would be launched almost on demand and would fly many missions each year. Throughout the history of the program, a gap has persisted between the rhetoric NASA has used to market the Space Shuttle and operational reality, leading to an enduring image of the Shuttle as capable of safely and routinely carrying out missions with little risk.



President Bush addresses a memorial for the STS-107 astronauts at Johnson Space Center on February 4, 2003.

The CAIB members concluded:

... The Shuttle has few of the mission capabilities that NASA originally promised. It cannot be launched on demand, does not recoup its costs, no longer carries national security payloads, and is not cost-effective enough, nor allowed by law, to carry commercial satellites. Despite efforts to improve its safety, the Shuttle remains a complex and risky system that remains central to U.S. ambitions in space. Columbia's failure to return home is a harsh reminder that the Space Shuttle is a developmental vehicle that operates not in routine flight but in the realm of dangerous exploration.

CAIB gave Bush the political ammunition to cancel Shuttle and propose a new direction. In response, NASA conducted the Exploration Systems Architecture Study that essentially returned the U.S. manned space flight program to the design used for Mercury, Gemini and Apollo — a crew vehicle atop a rocket.


Conceptual design of a Dyna-Soar atop a Titan booster.

Early NASA and military engineers explored the idea of a "space plane" atop a rocket, instead of being attached to the side. The X-20 Dyna-Soar would have mounted a "space plane" atop a military rocket.

More recently, the Orbital Space Plane was another attempt to mount a winged vehicle atop a rocket, but the research was eventually folded into Constellation.


Orbital Space Plane concept.

Both efforts were an attempt to correct the mistake made with Shuttle — mounting the crew vehicle on the side.

And that's why Bush cancelled Shuttle.



Click here to read the Report of the Presidential Commission on the Space Shuttle Challenger Accident.

Click here to read the Columbia Accident Investigation Board report.

5 comments:

  1. Som comments to your excellent commentary:

    1. "Space Transportation System" referred originally not just to Shuttle, but to Shuttle, Station, and the Space Tug, which was never constructed. The goal was a system that could access both LEO and higher orbits.

    2. Almost all launch vehicle failures are due to unanticipated failure modes. Once the nature of the failure is understood, the problem can be corrected. Although a new generation of shuttle might be constructed differently, the Shuttle is safe. It has had no significant tile damage in over five years. Strangely the loss of Challanger is treated entirely differently by supporters of Constellation, as though the SRBs are now perfectly safe, yet the accident proves the Shuttle is dangerous.

    The CAIB stated that Shuttle could and should continue to fly until a replacement vehicle was operational.

    ReplyDelete
  2. where does he mention the Constellation program obama shut down. the Constellation program was to replace the shuttle program and obama shut that down.

    ReplyDelete
    Replies
    1. He shut it down because it was wasting money. Instead, they are working on the Orion Project, and are under budget, by a lot by the way. Also, he funded missions to asteroids as a safety system in case one comes our way. He also increased NASA's budget. So, yeah he got it right.

      Delete
  3. This comment has been removed by a blog administrator.

    ReplyDelete
  4. The President alone cannot cancel anything. Congress has to go along. Which it did.

    Constellation was not "to replace the shuttle program." The Shuttle was designed for constructing the International Space Station. Neither the Ares I or Ares V was capable of being the "space truck" that was the Shuttle. It would be proper to say that Constellation was to follow Shuttle, but it sure wasn't intended to "replace" it nor was it going to preserve more than maybe 1,000 Shuttle-related contractor jobs for many years.

    Constellation was cancelled for a very good reason. Actually, lots of reasons.

    The main reason was it was years behind schedule and billions over budget. It was the subject of a number of scathing audits over the years by the Government Accountability Office. The fatal blow was the one in 2009 which said Constellation "lacked a sound business case" because Ares I was being built to fly astronauts to the ISS no earlier than 2017, but Ares I would be funded by decommissioning the ISS in 2015. In short, NASA was spending billions to build a rocket with no place to go.

    The first test flight in 2009 was the Ares I-X, not the Ares I. It was a prototype first stage with dummy upper stages. This test had a lot of problems. The next test, Ares I-Y, wasn't scheduled until 2013.

    And if you read the next article in this series, "After Bush Cancelled the Space Shuttle," you'll find that all the problems with Constellation were known from the very beginning:

    http://spaceksc.blogspot.com/2010/11/after-bush-cancelled-space-shuttle.html

    On January 28, 2004, NASA Administrator Sean O'Keefe told the Senate Science Committtee it would be a minimum four-year gap after the end of Shuttle where NASA would rely on Russia to ferry astronauts to the ISS. By 2009, that gap had grown to 6-7 years.

    President Obama said during an August 2008 campaign stop in Titusville that he would close the gap. He's keeping that promise by using the savings from cancelling Constellation to extend the ISS, accelerate the commercial cargo program begun by the Bush administration in 2004, and expanding the program to begin commercial crew.

    The problem now is that Congress keeps cutting the funding for commercial crew to bankroll the Space Launch System -- which, like Ares I, has no place to go since Congress only told NASA to build the rocket but hasn't given NASA any missions for it.

    The first commercial cargo flight is scheduled for April 30, just 13 days from now. A NASA official yesterday said that, if NASA had built the SpaceX Falcon 9 and Dragon, it would have cost 4 to 10 times more than what it's actually cost. So I'd say the current administration and Congress made the right call in 2010 when they decided to cancel Constellation and invest in technology that will actually fly, and fly soon.

    ReplyDelete