NASA’s flawed plan to return humans to the Moon
by Gerald Black
|The plan is flawed, and it is deeply troubling that NASA is discouraging innovation by only awarding study contracts and the related funding to companies that follow the NASA plan.|
The three vehicles would be launched separately and assembled at the Gateway. The Gateway is a space station of sorts that NASA is planning to construct in a highly elliptical near-rectilinear halo orbit (NRHO) around the Moon. This space station was originally called the Deep Space Gateway, but later was renamed the Lunar Orbital Platform-Gateway and is now generally referred to simply as the Gateway.
The transfer vehicle would propel the lander from the Gateway to a low lunar orbit, where it would separate from the lander and return to the Gateway for refueling. The lander would land on the Moon using the descent stage rocket engines. Astronauts would return from the lunar surface to the Gateway using the ascent stage. The goal is for the first crewed landing to occur in 2028.
There are two positive aspects of the new program. First, the three new vehicles would be developed using public-private partnerships, whereby the companies contribute money to the development in the hope of future profits. The final contracts will be fixed-price contracts, as opposed to cost-plus contracts that are always much more expensive. NASA has learned its lesson well in this regard from the abysmal performance of the Space Launch System (SLS) and Orion spacecraft, both with cost-plus contracts.
The second positive aspect is that the three new vehicles will be reusable. The goal is for the transfer vehicle and the ascent stage to be reusable from the get-go. Refueling of these vehicles would be done at the Gateway, initially using propellants transported from the Earth. However, the goal is that eventually the propellants would be obtained from lunar resources using in situ propellant production. The descent stage would initially be expendable, but eventually will evolve to be reusable using in situ propellant production.
However, the NASA plan has a major flaw, and that is that its architecture is built around the Gateway. The Gateway is a diversion that would delay the return of astronauts to the lunar surface by many, many years (see “The Lunar Orbital Platform-Gateway: an unneeded and costly diversion”, The Space Review, May 14, 2018.) Stopping at the Gateway on the way to the Moon is not needed and is in fact detrimental, since it requires more propellant than simply going directly to the Moon. The need for the third new vehicle in NASA’s plan, the transfer vehicle, exists in part because of the extra delta-v (change in velocity) required to stop at the Gateway.
Both the Space Launch System (SLS) and the Orion spacecraft, which will service the Gateway, utilize cost-plus contracts, where there is no incentive to reduce the costs. This is the kind of contract that resulted in $640 toilet seats, a $,7600 coffee pot, and $24 million dollars for refrigerators on Air Force One. The SLS, which will be used to launch most of the Gateway modules and possibly some of the new vehicles, is 100 percent expendable. The cost penalty for being expendable increases with the size of the launch vehicle, and the huge SLS will cost between one and two billion dollars per launch. Ouch!
|My estimate is that it would be the late 2030s or 2040s before America returns humans to the lunar surface if all we do is blindly follow the current NASA plan without significantly increasing NASA’s budget.|
The Gateway would drain at least $3 billion a year from the NASA budget, in large part because it relies heavily on the SLS and Orion for transportation between Earth and the Gateway. Since the NASA budget is unlikely to increase significantly, this leaves inadequate funding to develop the three new vehicles. Hence, the lander’s descent and ascent stages would be developed in sequence rather than in parallel. In the Phase A studies that the companies will soon be submitting proposals for, only the descent stage, transfer vehicle, and refueling elements are eligible for funding, with the lion’s share of the funding going to the descent stage. Zero funding will be allocated for the ascent stage.
Inadequate funding, coupled with sequential rather than parallel development, is a prescription for schedule delays and cost overruns. Just look at the SLS. Because NASA didn’t have enough funding to develop all the desired elements of the SLS in parallel, NASA decided to develop consecutively three SLS configurations with increasing capability. But the initial Block 1 configuration is already years behind schedule, and the Block 1B and Block 2 configurations are distant visions that may never be built. The Apollo program was successful because it had adequate funding and all hardware was developed in parallel.
Besides developing the three new vehicles, the Gateway must also be completed before it all comes together. The history of the ISS shows that it takes much longer to construct space stations than originally planned. In Ronald Reagan’s 1984 State of the Union address, he set the goal of completing the ISS within a decade. However, it wasn’t completed till 2011, 27 years after the program was initiated. My estimate is that it would be the late 2030s or 2040s before America returns humans to the lunar surface if all we do is blindly follow the current NASA plan without significantly increasing NASA’s budget.
Fortunately, there are better alternatives to NASA’s plan that do not rely on the Gateway. Robert Zubrin’s Moon Direct is one such plan. This plan can be accomplished using existing launch vehicles such as the Falcon Heavy. Only two new vehicles, a cargo lander and a Lunar Excursion Vehicle (LEV), would be needed. The LEV would be reusable, travelling back and forth between low Earth orbit and the lunar surface. It would initially only be refueled in low Earth orbit, but eventually would also be refueled on the lunar surface using in situ propellant production. Until such time that in situ propellant production is operational, the LEV would be transported to the Moon fully fueled aboard the cargo lander. Thereafter, the LEV would land on its own and conduct exploration by performing point-to-point sortie missions to most of the Moon.
United Launch Alliance (ULA) has been developing its own plan that utilizes its Vulcan rocket, its ACES reusable upper stage, and the Xeus lunar lander it has been studying with Masten Space Systems. Blue Origin has been developing yet another plan that utilizes its New Glenn rocket (and perhaps its New Armstrong rocket) and its Blue Moon lunar lander. Unfortunately, to secure NASA funding, ULA and Blue Origin will be compelled to alter their plans to fit the NASA architecture.
|The best strategy is to encourage innovation by funding studies of alternative plans as well as the NASA plan.|
However, Elon Musk’s bold plan is head and shoulders above any other. This plan would utilize SpaceX’s massive Big Falcon Rocket (BFR), comprised of the Super Heavy first stage and the Starship second stage. The Starship would be refueled in Earth orbit using Starships modified to act as tankers. The refueled Starship is capable of transporting cargo and/or crew to the lunar surface and return to Earth without the need to refuel on the Moon. This plan has the advantage that everything is fully reusable from the start, making it the lowest cost plan by far. Each mission would also land far more cargo and crew than alternative plans, which would help speed up construction of a lunar base.
Test flights of a subscale Starship “hopper” vehicle are scheduled to begin in the first half of this year. A full-scale Starship vehicle and the Super Heavy booster may be ready for testing in 2020. Although rapid progress is being made by SpaceX using its own funds, SpaceX needs funding from NASA to maintain this progress and to exploit the lunar transportation capabilities of the BFR.
The best strategy is to encourage innovation by funding studies of alternative plans as well as the NASA plan. It is also important to develop two independent means of returning humans to the lunar surface. We now have two (soon to be three) American companies supplying cargo to the ISS, and we will soon have two American companies transporting crew to the ISS. Likewise, we should have at least two American companies providing independent systems to transport crew to a lunar base.
Competition keeps the cost down. More importantly, independent systems provide a backup in case a rocket or spacecraft failure forces one system to stand down. Having multiple companies supplying cargo to the ISS was of critical importance during the period from October of 2014 through December of 2016, when four different resupply missions to the ISS failed. With the current NASA plan, it will be impractical to fund two independent systems, since we can’t even afford a single system without a lengthy development program.
The current plight began in 2010 when the US Senate mandated development of the SLS. Hence the SLS is sometimes referred to as the Senate Launch System. Perhaps SLS should stand for stop, look, and squander. In order to give the SLS something to do, NASA invented the Gateway. Now to justify the Gateway NASA wants to develop three new vehicles that use the Gateway to transport humans to the lunar surface. The folly is exposed since better plans to land humans on the lunar surface have been formulated that don’t require use of the Gateway. If we’re serious about returning humans to the lunar surface in the next decade, then we must cancel the SLS, Orion, and Gateway boondoggles so we can fully fund one or, better yet, two alternative plans.
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