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NASA intends to squander billions of dollars for a "lunar toll in orbit." A private spaceship could offer faster and cheaper moon boots.
This editorial was published in SpaceNews magazine on April 8, 2019.
NASA proposed to build a space station in lunar orbit, called the moon gate, to use as a base for lunar exploration. This plan is seriously flawed.
The Gateway project can be compared to a contract in which you can rent an office in Thule, Greenland, under the following conditions: 1. You pay for the construction of the building. 2. You accept a 30 year lease with high monthly rents and no exit clause. 3. You agree to spend one month a year for the next 30 years. 4. You agree to fly by Thule from now on.
Few would find such a proposal attractive. The moon gateway project is not better. It will cost a fortune to build, a fortune to maintain and will increase the costs, risks and time constraints of all subsequent missions on the Moon or Mars by adding an unnecessary stop along the way.
To understand how suboptimal a Moongate plan is, we need to compare it to what would be done as part of a well-designed effort to get the job done as quickly and efficiently as possible. The plan to do lunar exploration this way is called Moon Direct.
Here's how it would work: In the first phase, which precedes any human mission, we deliver habitat modules and other cargoes to the intended base on the lunar surface.
The SpaceX Falcon Heavy can lift about 60 tonnes in LEO. From this point, a cargo landing gear powered by a hydrogen / oxygen rocket could provide 10 tons of payload to the lunar surface.
We proceed by sending two of these undercarriages to our planned base location. The best place for this would be at one of the poles, as there are places at both poles of the moon where sunlight is permanently accessible, as well as permanently shaded craters nearby, where the water ice has accumulated. Such ice could be electrolyzed to make a hydrogen-oxygen rocket booster, to power both land-return vehicles and flying rocket vehicles that would provide the base crew with exploratory access to most of the aircraft. rest of the moon. We will not just have a local station: we will have full global access to a whole world.
The first goods lander carries a load of equipment, including a group of solar panels, high-speed communication equipment, a microwave transmission facility with a range of 100 km, an electrolysis / refrigeration unit, two crew vehicles, a trailer and a vehicle. group of robotic rovers teleoperated. After landing, some of the rovers are used to configure the solar panel and the communication system, while others serve to explore in detail the landing zone, by placing radio beacons on the locations. precise targets for landings to follow.
The second cargo lander offers a 10-ton housing module, loaded with food, spare combinations, scientific equipment, tools and other supplies. This will serve as home of astronauts, laboratory and workshop on the moon. Once it has landed, mobiles connect it to the power supply and all systems are checked. This done, the rovers are redeployed to make detailed photographs of the base and its surroundings. All of this data is sent back to Earth to help mission planners and science and engineering support teams. They ultimately form the basis of a virtual reality experiment that will enable millions of members of the public to participate in missions by proxy.
The base is now operational, so it's time to send the first crew. A Falcon Heavy is used to bring another landing gear into orbit, whose payload consists of a fully powered lunar excursion vehicle. This vehicle consists of a 2-ton cabin similar to that used by the Apollo-era lunar excursion module, as well as an 8-ton hydrogen / oxygen propulsion system, capable of transport from the lunar surface to the Earth's orbit. A human-sized SpaceX Falcon 9 rocket then takes the crew into a LEO Crew Dragon capsule where it is transferred to the LEV. Then, the lander carries the LEV, with the crew on board, on the Moon, while the crew's Dragon stays behind.
After landing at the lunar base, the crew completes the necessary configuration and begins exploration. A key goal will be to visit a permanently shaded crater and, using the power returned to them from the base, use telerobots to extract the ice from the water. By bringing this treasure back to the base in their caravan, the astronauts will inject the water into the electrolysis / refrigeration unit, which will turn it into liquid hydrogen and oxygen. These products will then be stored in the empty cargo-level tanks for future use – primarily as a rocket propellant, but also as a fuel source for fuel cells and an abundant source of life-sustaining consumables.
After spending a few months launching such operations and engaging in other forms of resource exploration and scientific exploration, the astronauts will enter the LEV, take off and return directly to Earth orbit. They will then be greeted by a crew dragon – either the one who would have brought them into orbit at first, or another who has just been launched to lift the crew that was following them – which will serve them well. return capsule for the last leg of the trip back home.
Once several missions of this type have been completed, a large propellant stock will be put in place at the base and water and propellant manufacturing operations will have been reduced to practice. so that they can be performed in a fully automated way. We will also have several LEVs used, available, floating in Earth orbit. This being the case, the third phase missions can be carried out simply by using a mid-size Falcon 9 (or Blue Origin New Glenn or United Launch Alliance Vulcan) to lift the crew into orbit in a capsule. LEV with 7.5 tons of refueling propellant, then fly to the moon. In addition, once on the moon, the LEV can be refueled at the base booster depot for outbound flights at remote locations, before being refueled for the return flight.
With more equipment arriving for each mission, basic capabilities will increase rapidly, the population that can be supported will increase and the duration of missions will increase from a few weeks to several months, or even years. When this happens, the base will move from local activity to a center supporting a vigorous lunar exploration program spanning the globe.
Now compare this plan to another involving the use of the lunar bridge. The Gateway plan is to use SLS boosters, which can be launched once every two years, to deliver four modules to build the lunar orbit station. It will take eight years and, with an SLS cost of $ 2.5 billion a year, US taxpayers will have a $ 20 billion bill, not to mention the cost of the station's equipment, which will likely cost $ 10 billion. additional dollars. (In an article published on March 11, NASA suggested using commercial launchers to build the station, in which case the space agency will pay $ 2.5 billion a year for the SLS without using it. the cost of the station's equipment, plus the cost of commercial launches.) Then, after this very costly delay, an SLS launch will be used to send a crew to the station in an Orion capsule. There, they will have to wait for another launch of SLS to provide a fully powered landing gear to the station, which they will use to get to the surface of the Moon and return, after which they will return to Earth with Orion. Two SLS launches will therefore be needed at a launch cost of $ 5 billion per mission, if it is possible to double the SLS launch rate to one per year. They will also have to perform three maneuvers of critical appointments, including an essential rendez-vous for life with the station on the way back. Since the Moon Bridge will be in an 11-day orbit, opportunities to return to Earth will rarely occur. If they miss the bus, they might not be lucky.
Of course, if someone was also establishing a polar moon base with a propeller production capability – as proposed in the Moon Direct plan – and was developing a LEV to refuel at the base, it could be used as a ferry reusable between the base of the moon and the lunar door. It would be a very smart thing to do, because in this case, it would only be necessary to use a single launch of SLS by lunar mission to route the Orion with crew from the Earth to the bridge.
However, since the round-trip propulsion required to move between the bridge and the lunar surface (a 6 km / s V-Delta) is identical to that required to fly in a lunar surface direction to a terrestrial orbit low, the same LEV that could serve as a ferry between the lunar base and the bridge could also be used to fly from the lunar base directly to LEO. There, he could be re-equipped with a crew and enough propulsion to send him back to the moon using a single launcher carrying the dragon Falcon 9, costing only $ 65 million. Not only would this reduce mission launch costs by a factor of 40, but their mission mode would be much safer, since seen from the surface of the moon, the Earth is still in the same place, so the launch window is always open. Moreover, unlike the SLS which can only hope to be launched once a year, the Falcon 9 already fly twice a month. So, not only will we have a lunar base, but we can use it.
In short, in return for delaying our arrival on the Moon eight years and our $ 30 billion spent on the construction of the bridge, NASA will allow a lunar base program costing $ 2.5 billion per flight instead $ 65 million per flight, and will be less safe and remote. less useful than would be easily possible if we had no gateway at all!
However, the NASA lunar Tollbooth in orbit problem (to use more precise terminology) goes far beyond the waste of decades and tens of billions of dollars and the damaging distortions it will impose on planning. of the mission. The deeper problem is the form of thought that it represents.
NASA's planetary astronomy and planetary exploration programs have accomplished epic feats because they goal-oriented. On the other hand, since the end of Apollo, NASA's manned space flight program has no purpose, or to speak less charitably, focused on the seller. As a result, his achievements have been negligible.
Scientific programs spend money to do things. The manned space flight program does things to spend money.
The situation is really ironic. With the success of Falcon Heavy, the United States could prepare for a breakthrough in space. The money available is enough. The Lunar Orbit Tollbooth funds, if they were used instead for entrepreneurial development contracts of landers and Moon Direct tour vehicles, could allow a return to the Moon from here. four years. With powerful lunar exploration missions requiring only one medium launch, the lunar base will be eminently sustainable and the country will be able to steer its heavy transport capabilities and ambitions towards Mars.
Instead of being unnecessarily confined to a lunar orbit, American astronauts can be explorers of new worlds. As we did in the 1960s, we can once again amaze the world with what free people can do. As we approach the 50th anniversary of the first landing on the moon, which reminds us of the kinds of things we nations have accomplished, we should strive to do nothing less.
Robert Zubrin is president of Pioneer Astronautics and the Mars Society, and author of the forthcoming book "The Case for Space: How the Space Flight Revolution Opens a Future of Unlimited Possibilities" (Prometheus 2019), from which this article is suitable.
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