Can NASA develop a heavy-lift rocket?
by Jeff Foust
|“While the Authorization Act sets a goal of 2016, a first flight this early does not realistically appear to be possible” for NASA’s proposed HLV design, according to its report to Congress.|
Last week, NASA concluded that, given the language in the report, developing such a rocket wasn’t possible: it would cost more and take longer. That’s an answer some members of Congress seem unwilling to accept, pushing back on the agency go back and try again. The real questions may not be about the agency’s capabilities but instead whether there are too many constraints—capabilities, budget, schedule, and design—for NASA to develop an HLV, as well as the mission for such a rocket.
What kicked off the latest debate about HLV development was a report delivered to Congress by NASA on January 11, titled “Preliminary Report Regarding NASA’s Space Launch System and Multi-Purpose Crew Vehicle”. The document is also known as the “Section 309” report after the section of the authorization act that required NASA, within 90 days of the legislation’s enactment, to provide a “detailed report” on the development of the SLS and Multi-Purpose Crew Vehicle (a successor to, if not outright continuation of, the Orion spacecraft), including a description of the current reference design for each and various technical, contractual, and other issues.
Ninety days isn’t long to come up with a new vehicle design, but NASA had a head start in that it had been examining concepts for HLVs with its Human Exploration Framework Team (HEFT), established last year. In the Section 309 report, NASA notes it carried out a “Figures of Merit” study of various HLV concepts last fall at the Marshall Space Flight Center, looking at various concepts. From that, NASA selected one of those concepts as its Reference Vehicle Design: a vehicle with a core stage with the same 8.4-meter (27.5-foot) diameter as the shuttle’s external tank, powered by five Space Shuttle Main Engines (SSMEs) and two five-segment SRBs; a J-2X engine would propel an upper stage that would give the vehicle its ultimate 130-metric-ton capability. It is quite similar to the Ares 5, which used five-and-a-half-segment SRBs and six RS-68 engines in its core stage.
The new HLV design, the report states, complies with direction in the authorization act to make maximum use of Shuttle and Constellation hardware and capabilities. There are just two problems: the design doesn’t fit into the budget, nor can it be ready by the 2016 deadline in the act. “[N]one of the design options studied thus far appeared to be affordable in our present fiscal conditions, based upon existing cost models, historical data, and traditional acquisition approaches,” the report states in the introduction. And a bit later in the report: “While the Authorization Act sets a goal of 2016, a first flight this early does not realistically appear to be possible based on our current cost estimates for the Reference Vehicles and given the levels proposed in the Authorization Act.”
That conclusion didn’t sit well with key members of the Senate, where the authorization act originated last summer. In a brief statement jointly issued by Sens. Jay Rockefeller (D-WV), Kay Bailey Hutchison (R-TX), Bill Nelson (D-FL), and David Vitter (R-LA)—the chair and ranking member of the full Senate Commerce Committee, and chair and ranking member of its space subcommittee, respectively—they reminded NASA that meeting the 2016 deadline in the bill was a requirement. “[T]he production of a heavy-lift rocket and capsule is not optional. It’s the law,” they said. “NASA must use its decades of space know-how and billions of dollars in previous investments to come up with a concept that works. We believe it can be done affordably and efficiently—and, it must be a priority.”
In a separate letter Thursday to NASA administrator Charles Bolden, Hutchison and Nelson went into further detail about their concerns with the Section 309 report. “The report contains no specific justification or analyses to validate the claim that ‘none of the design options studied thus far appeared to be affordable in our present fiscal conditions,’” they wrote, referring to the lack of detail, including estimated costs, in the report.
|“[T]he production of a heavy-lift rocket and capsule is not optional. It’s the law,” the senators said.|
The senators argued in their report that NASA should focus on existing, shuttle-derived technologies and focus more energies in refining the techniques they use to manage the program, rather than study new technologies—as NASA is currently doing with a series of trade studies awarded late last year to 13 companies. “Previous studies by both NASA and industry have indicated that, by building on past investments and available technologies, NASA can reach initial operating capability of a scalable heavy-lift launch vehicle with the funds authorized, especially if the agency refines its procurement, contract management, and oversight processes,” they wrote.
In the Section 309 report NASA did indicate it was “exploring more innovative procurement and development strategies” for the SLS development. “It is clear that innovative, lower cost ways of doing business and expedited processes at all levels must be implemented for SLS to achieve the first flight milestone anywhere near” the end-of-2016 deadline in the authorization act. The report contained few details about those management innovations, beyond providing incentives for contractors to find ways to reduce costs and “address cultural changes within the Agency to focus more on affordability rather than just performance factors.”
NASA’s claim that an HLV meeting the specifications laid out in the authorization act can’t also meet the cost and schedule requirements in the same legislation opened the agency to criticism in recent days from those who believe that there are alternative designs that can be done on budget and schedule.
In a blog post Friday at the web site of Air & Space magazine, Paul Spudis of the Lunar and Planetary Institute made the case for a shuttle-derived HLV concept known as a “sidemount”. Unlike “inline” vehicles like the reference design in the report or the Ares 5, where the payload is atop the vehicle, the sidemount concept places the payload, as well as its main engines, on the side of the vehicle, just as the shuttle is mounted on the side of its external tank. Such concepts date as least as far back as “Shuttle-C” in the mid-1980s.
Spudis presented a chart derived a report with the cryptic title “SSP Study NSTS 60583”, developed at the Johnson Space Center last summer. That chart shows the estimated development costs and schedules of a few HLV concepts, including both a sidemount vehicle and one effectively identical to the reference SLS design. According to that study, the reference design would cost $14.9 billion to develop and not be ready for operations until 2018. (Adding an upper stage to increase its payload to 130 metric tons adds $2 billion to its development cost and delays its introduction to 2021.) The sidemount vehicle, though, would cost nearly 50 percent less to develop—$7.6 billion—and be ready by 2017, as required by the authorization act.
|“Overall, you have to be completely blind not to see that the budget and implementation time window simple doesn’t support any HLV that doesn’t have most of its elements already flight qualified and in production,” Metschan said.|
“The advantage of SSM [Shuttle Side-Mount] is that, as it is a minimal modification of the existing stack, it uses all of NASA’s existing launch and processing infrastructure—launch pads, mobile crawlers, scaffolding in the VAB and fabrication facilities in Michoud and Utah,” Spudis wrote. The vehicle easily meets the requirement of launching 70–100 tons to LEO and can be modified—through the use of five-segment SRBs, an additional main engine, and a stretched tank—to meet the 130-ton goal. “So in fact,” he concludes, “SSM meets all the technical, budgetary, safety and schedule requirements set out in the NASA Authorization Act of 2010.”
However, a sidemount design might be tripped up by other legislative language. The report accompanying the Senate version of the authorization bill (the one later passed by the House and signed into law) went into more details about what the authors of the legislation see as the preferred concept for an HLV:
The [Senate Commerce] Committee anticipates that in order to meet the specified vehicle capabilities and requirements, the most cost-effective and ‘evolvable’ design concept is likely to follow what is known as an ‘in-line’ vehicle design, with a large center tank structure with attached multiple liquid propulsion engines and, at a minimum, two solid rocket motors composed of at least four segments being attached to the tank structure to form the core, initial stage of the propulsion vehicle. The Committee will closely monitor NASA’s early planning and design efforts to ensure compliance with the intent of this section.
That language, including the explicit reference to an inline design, suggests that a sidemount vehicle design might be an issue for some senators, such as those complaining to NASA about the current reference concept. Report language does not contain the force of law, but not being responsive to it would likely raise questions among those in Congress who got that section into the report (as noted by the “closely monitor” language in the same section).
While a sidemount design might not strictly meet the report language, another alternative design would: the Jupiter family of shuttle-derived vehicles that comprise the DIRECT architecture, developed in recent years by a team of engineers and others. They were so satisfied with the NASA authorization act that they effectively declared victory in a press release shortly after the bill was signed into law.
“From our perspective you couldn’t have asked for an authorization that was any closer in alignment than what we have been promoting now for many years,” said Stephen Metschan, one of the key people with DIRECT, in an email interview last week. He said he wasn’t surprised the NASA report concluded that their reference design couldn’t fit into the act’s budget and schedule. “Overall, you have to be completely blind not to see that the budget and implementation time window simple doesn’t support any HLV that doesn’t have most of its elements already flight qualified and in production.”
|“In the absence of any specific mission, the payload capacity of your launch vehicle is entirely academic,” Spudis wrote.|
(Both Metschan and Spudis complained about one aspect of the NASA report: its use of metric tons, or tonnes, instead of tons. Both noted that the legislation put its performance requirements in tons, which NASA has since interpreted as metric tons. One metric ton is 1,000 kilograms or 2,205 pounds, about ten percent more than a ton (2,000 pounds). “Going above the minimum 70 ‘ton’ requirement is spending more money than we need at this point in time regardless of the derivative platform,” Metschan said.)
Metschan said that DIRECT’s Jupiter-130 vehicle concept—which uses shuttle SRBs and three SSMEs mounted on an external tank—could be built on the budget and schedule of the authorization bill provided that NASA had a “hands-off” management of the project. He cited in particular SpaceX’s development of its Falcon 9 rocket, which was financially supported in part by NASA’s Commercial Orbital Transportation Services (COTS) program, but without the level of oversight of a typical agency program.
“It should be wakeup call to everyone that if an inexperienced organization developing all its hardware from scratch can achieve what it did in record time and cost with so little oversight from NASA, then the oversight we currently heap upon experienced companies flying existing hardware is overkill to the extreme,” he said.
The debate about how to build an HLV will likely raise another question: why build one now? The main reasons for building one as specified in the act are to “access cislunar space and the regions of space beyond low-Earth orbit” as well as provide a government backup to commercial and international systems to transport cargo and crews to and from the ISS. In the case of the latter the SLS is considerably oversized—the Ares 1 that had been under development for Orion was designed to place about 25 tons into LEO—while in the former case the specific transportation needs aren’t clear since NASA hasn’t settled on a specific exploration architecture.
“In the absence of any specific mission, the payload capacity of your launch vehicle is entirely academic,” Spudis wrote in his blog post. He proposes that at least the upper limit of the SLS’s capacity, 130 tons, is taken from the Saturn V, which could carry a similar payload. “One might suspect that the calculus was that heavy lift in days of old (Saturn V) meant 130 tons, so that’s what ‘heavy lift’ should be.”
But, of course, it’s not the old days, and a new era may require new justifications for spending billions on an HLV, particularly in the current, more fiscally conservative budget environment. NASA alludes to this in the report, noting that it still does not have a final budget for 2011, three and a half months after the fiscal year started. “[I]t is clear that final funding levels will drive many other key decisions NASA still needs to make, including schedule projections and acquisition plans,” the report states.
While that suggests it is up to Congress to adequately fund NASA in order for it to develop SLS, Metschan believes that it’s NASA that needs to come up with an adequate design that will win support—and funding—in Congress. “In the end it’s up to NASA: do they want to build upon what they have achieved thus far or do they want to start all over again with a smaller political support base and budget to match?”