Early next week, sleepy Monday morning commuters along the United States’ eastern seaboard will be jarred fully awake by a roar of rocket engines whose intensity has never been witnessed or heard in almost five decades. NASA’s mighty Space Launch System (SLS)—a 322-foot-tall (98-meter) behemoth, higher than the Statue of Liberty stands from her Liberty Island pedestal to the tip of her torch—is set to rise from historic Pad 39B at the Kennedy Space Center (KSC) for the uncrewed Artemis I mission of an Orion spacecraft to the Moon and back. It will mark the first voyage of a human-capable vehicle to lunar distance since Apollo 17, way back in December 1972.
It is astonishing to contemplate that Orion has been in development, and waiting for this first lunar flight, for longer than the entire Apollo Program from its start in the early 1960s to its finish in the mid-1970s. Orion arose from the ashes of tragedy, following the February 2003 loss of shuttle Columbia and her STS-107 crew. In January 2004, President George W. Bush announced a new Vision for Space Exploration (VSE) to complete the International Space Station (ISS), retire the aging shuttle fleet and return astronauts to the Moon and onward to Mars.
The president’s intent was for NASA to develop and test a new spacecraft, the Crew Exploration Vehicle (CEV), “by 2008” and execute an initial crewed flight “no later than 2014”. The CEV would deliver astronauts both to the ISS and Beyond Low-Earth Orbit (BLEO) destinations, supporting a return of boots to the lunar surface by 2020.
Organizational change within NASA Headquarters in Washington, D.C., to accommodate the VSE began immediately and Bush established a Commission on Implementation of the United States Space Exploration Policy to recommend future scientific agendas and requisite technologies, demonstrations and strategies to accomplish them. The results indicated broad public and state support for the VSE, on a ratio of 7:1.
“Our economy can certainly afford an effort of this magnitude, but the public must believe that the benefits to society deserve the investment,” cautioned Neil Armstrong in the commission’s June 2004 final report. “The rate of progress is proportional to the risk encountered. The public at large may well be more risk-averse than the individuals in our business, but to limit the progress in the name of eliminating risk is no virtue.”
NASA issued a draft statement of work for the CEV in December 2004, followed by a request for proposals in March 2005, with a potential for two contractors in a two-phase program. Phase I would entail risk-reduction demonstration flights no later than September 2008, ahead of a down-select to a single contractor for Phase II by late 2008.
In June 2005, NASA picked Lockheed Martin and a joint Northrop Grumman/Boeing team for Phase I. A month later, contracts worth $28 million apiece were awarded to the two competitors to mature their designs, but NASA Administrator Mike Griffin deemed the process unacceptably slow and eliminated the “fly-off” demonstration missions. Eager to shorten the “gap” between the end of the shuttle era and the first flight of the CEV, Griffin advanced the Phase II down-select by two years to August 2006, hopeful that it would shave off $1 billion in costs and achieve a first flight by June 2011.
Central to Griffin’s strategy was the Exploration Systems Architecture Study (ESAS), published in September 2005, which advocated launching the CEV on a shuttle-derived vehicle and cited the “superior safety, cost and availability” of the RS-25 Space Shuttle Main Engine (SSME) and the four-segment Solid Rocket Booster (SRB). Payloads for deep-space exploration would fly atop a Cargo Shuttle Derived Launch Vehicle (SDLV), with crewed CEVs launching via a booster based upon an extended, five-segment SRB.
In its January 2006 Phase II request for proposals, NASA identified the CEV as a blunt-bodied, capsule-type spacecraft, capable of transporting up to six astronauts to and from the ISS or up to four astronauts to and from the Moon. In a sense, it borrowed its shape from the space capsules of yesteryear, whilst leveraging modern technologies in the fields of computers, electronics, life-support systems, propulsion and thermal protection.
On 22 August 2006, the new spacecraft was formally named “Orion”, in honor of “one of the brightest, most familiar and easily identifiable constellations”. NASA noted that many of Orion’s stars had been used for centuries for navigation, helping to guide explorers to new worlds. And the architecture of Orion—which included the Ares I booster to lift crew and the giant Ares V for heavy-lift cargo—came to be known as “Constellation”.
Nine days after naming Orion, Lockheed Martin won the contract to build the spacecraft, with the initial design, development, testing and evaluation phase totaling $3.9 billion and extending seven years from September 2006. The following April, the contract was modified to $4.3 billion, with two years added to the design phase and two test flights of Orion’s Launch Abort System (LAS) built into the schedule for added robustness.
Work got underway in short order. Initial testing of parachute systems began at the U.S. Army’s Yuma Proving Ground, near Yuma, Ariz., whilst Boeing was selected in September 2006 to support the design of Orion’s heat shield, which would guard the capsule at lunar-return re-entry velocities over 25,000 miles per hour (40,000 kilometers per hour). Options for the shield included Phenolic Impregnated Carbon Ablator (PICA), with alternate technologies also explored in subsequent contracts.
For more than three years, NASA worked on eight candidate heat shield materials, before narrowing them to the flight-proven PICA and Avcoat, the latter of which had been utilized on the Apollo Command Module (CM). In April 2009, Avcoat’s system was selected.
It comprised silica fibers with an epoxy-novalic resin, filled in a fiberglass-phenolic honeycomb and manufactured directly onto Orion’s heat shield substructure. This would then be installed as a complete unit onto the base of the Crew Module (CM).
Elsewhere, other aspects of Orion’s development continued. Reviews of launch vehicle and spacecraft systems requirements were conducted, with more than 1,700 performance, design and qualification issues closed out by May 2007. This cleared the road for major systems definition reviews, leading to the Preliminary Design Review (PDR) then targeted for mid-2008 and the Critical Design Review (CDR) in mid-2010.
In April 2007, NASA partnered with the Air Force’s Space Development and Test Wing at Kirtland Air Force Base, near Albuquerque, N.M., to stage a series of six LAS tests in 2008-2011 for an escape mechanism to pull the Orion CM to safety in the event of a launch failure. Groundbreaking for construction of the abort test pads began at the Army’s White Sands Missile Range, near Las Cruces, N.M., in November 2007.
And early the following year a full-scale, 20,000-pound (9,000-kilogram) Orion CM test structure was shipped to the Dryden Flight Research Center at Edwards Air Force Base, Calif., for the “Pad Abort-1” test.
Concurrently, in April 2008 a solid-fueled motor to jettison the LAS during ascent was static-fired by Aerojet at its facility in Sacramento, Calif. And ATK Thiokol performed tests of the LAS igniter system and test-fired the motor for 5.5 seconds at its Promontory, Utah, site in November 2008.
This paved the way for Pad Abort-1, which took place at White Sands on 6 May 2010. The abort motor, generating a momentary 500,000 pounds (226,800 kilograms) of thrust, burned for six seconds to lift the Orion CM test structure away from the pad. It achieved peak velocity of 540 miles per hour (870 kilometers per hour).
A 7,000-pound-thrust (3,170-kilogram) attitude-control motor provided steering and a jettison motor pulled the LAS away from the capsule to permit parachute deployment and a safe landing. All told, Pad Abort-1 lasted 135 seconds and brought the capsule to a smooth touchdown about a mile (1.6 kilometers) north of the test pad.
In tandem with these highly visible tests, the performance of Orion in other areas was being steadily proven and brought nearer to flight readiness. In March 2009, a full-scale mockup of the spacecraft was emplaced in a test pool at the Naval Surface Warfare Center’s Carderock Division in West Bethesda, Md., to understand the motions astronauts might experience after a water landing.
Orion swept through its PDR with flying colors in August 2009. This prompted Cleon Lacefield, vice president and Orion Project Manager at Lockheed Martin, to remark that its design was far more robust than would normally be expected at the PDR checkpoint. By this stage, the design of the new spacecraft had seen Lockheed Martin and NASA labor through 300 technical reviews, 18 subsystem design reviews and a hundred peer reviews.
Designing the rocket that Orion would ride was also well into development. From February 2006, engineers at NASA’s Marshall Space Flight Center (MSFC) in Huntsville, Ala., began wind-tunnel testing of what came to be known as the Ares I Crew Launch Vehicle (CLV).
This two-stage rocket, with a payload capacity of 50,000 pounds (22,300 kilograms), featured a first stage fabricated by ATK Thiokol—builder of the shuttle’s SRBs—to be topped off with a Boeing-built second stage, fed by Pratt & Whitney Rocketdyne’s J-2X engine. The latter represented an evolved, modernized version of the selfsame engine used by the Saturn IB and Saturn V boosters in the Apollo Program.
The J-2X, it was intended, would not only power the Ares I CLV’s second stage, but also the much larger Ares V Cargo Launch Vehicle (CaLV). The “Ares” nomenclature honored the Greek syncretism of the ancient Roman god of war, Mars, whose planetary namesake was the major eventual destination of the VSE.
Construction of a 300-foot-tall (90-meter) test stand at NASA’s Stennis Space Center (SSC) in Bay St. Louis, Miss., commenced in mid-2007 for full-scale tests of the J-2X hardware, including its powerpack and gas generator. The engine itself passed its CDR in November 2008, which allowed it to move into manufacturing. And Boeing began work on the development of the Ares I avionics.
Meanwhile, ATK Thiokol inked a $1.8 billion contract with NASA in August 2007 to build a five-segment SRB for the Ares I first stage and as side-boosters for the Ares V. Under the terms of the contract, a high-altitude test flight of the booster—“Ares I-X”—would be performed, using a standard four-segment SRB and a dummy, “ballasted” fifth segment to render an aerodynamically accurate analog for the real thing.
Hardware for Ares I-X began to arrive at the KSC in November 2008, followed by the Solid Rocket Motors (SRMs) in March 2009. Launch was targeted for July 2009, but found itself delayed until October when historic Pad 39B could not be handed over by the Space Shuttle Program to the Constellation Program for modification until late May.
Although the “Orion” to be flown on Ares I-X was actually little more than a boilerplate CM, topped by the 46-foot-tall (14-meter) LAS, it was nevertheless instrumented with over 150 sensors to measure temperatures and pressures and understand vehicle performance. A further 550 sensors were mounted onto the Ares I-X airframe itself.
The 327-foot-tall (100-meter) booster roared aloft at 11:30 a.m. EDT on 28 October 2009, pushing uphill with 2.6 million pounds (1.2 million kilograms) of thrust. The six-minute flight, from launch through parachute deployment and splashdown of the booster, was an unbridled success.
But sadly, the following year, 2010, would bring the Constellation Program to the brink of cancelation as a whole new architecture for BLEO exploration assumed center-stage. Although the year began well with the Pad Abort-1 test in May, and ATK Thiokol test-fired the five-segment SRB in Utah for a full mission duration of two minutes on 31 August, President Barack Obama had already signaled NASA to terminate Constellation, end work on Orion, Ares I and Ares V and adopt a new space exploration agenda. It was a decision which earned the new president both praise and vilification.
The second part of this article will appear tomorrow.Missions » SLS »