US Aerospace Agency NASAconsiders, as an alternative to its own super-heavy SLS carrier rocket, which has been developed for at least the last decade, the idea of using a commercial carrier to launch the very important mission for the agency to send the Orion spacecraft around the moon next year. The decision can be not only fateful for the designated mission, but in general can have a serious impact on how ambitious space missions will be carried out into deep space in the future, according to the Internet publication The Verge.
The incentive for the “hold nose” agency to the sidecommercial orientation may be a desire to fulfill his promise to them according to the schedule of planned launches, the publication considers. Completing the development of a super-heavy Space Launch System (SLS) will take the agency much longer than expected, and the media will not have time to prepare for the launch planned for June 2020. At the same time, the market already has ready-made commercial solutions that are ready to fly to the moon right now.
For NASA, a change in plans anywayprove to be a difficult choice. After all, the agency will need to choose not one, but two launch vehicles, so that in this case the mission could be made a reality. In addition, it will be necessary to develop new technologies and methods for docking certain spacecraft without which this idea can be thrown directly into the bin.
In other words, the process will require a lottime and effort, and at the same time no guarantee that everything will be prepared for the next year, no one can give. However, if the agency decides to take such a step, then by its actions it will be able to demonstrate the absence of the need to use ultra-expensive and extra-large rockets for successful implementation of ambitious space missions to deep space - it will be easier to rely on more compact carriers, performing several launches at a time.
According to current plans for the upcoming mission, NASAnext year, he wants to send two spacecraft to the three-week trip around the moon: the empty ship Orion (in the future it will be used as a manned spacecraft), as well as a cylindrical European Service Module with power and life support systems for the ship. It will take a lot of rocket fuel to overcome the force of attraction, to bring both vehicles to Earth orbit and send them to the Moon. However, the SLS capacity is enough to send both modules to a destination within one launch.
If NASA decides to use for delivery“commercial approach” to the Moon, you will have to use two commercial carriers, since there is simply no sufficiently powerful private rocket that can cope with this task in one go. At the moment, the most powerful American commercial rockets are Falcon Heavy from SpaceX and Delta IV Heavy from the United Launch Alliance. Both carriers are certainly impressive, but even they do not compare with the capabilities that SLS will have when it is finally completed.
In this case, one carrier will be used.to bring the Orion spacecraft and the European Service Module to the near-earth orbit, where they linger for a while. The second launch vehicle will be used for delivery to the Orion and the space tug service module. Once in orbit, this tug, equipped with its fuel reserves and engines, will dock with Orion and, having started the engines, will pull both vehicles towards the Moon.
"This is similar to agricultural technology,pulling a trailer or special equipment. Only in this case we are talking about a separate module, which is a propulsion system, ”commented The Verge Dallas Bienhoff, head of the private space company Cislunar Space Development Company, which develops technology for missions to deep space.
A similar concept of space tug wasdeveloped in the last century. For example, NASA began exploring this idea back in the 1960s and 1970s as a "promising method for accelerating other spacecraft." Its use can change the approach to manned space missions, which has not changed for many decades.
"One of the reasons that ultimately ledThe US’s development of the Space Launch System is that we’ve become accustomed to getting the maximum possible payload within one launch, ”adds Bienhoff, who also worked on space tug technology at Boeing.
However, this approach greatly complicates the launch. Earth gravity is very strong. Therefore, to bring very heavy equipment into space requires a lot of energy (read - a lot of rocket fuel). And the launch of a large amount of fuel requires the use of a large rocket. And the larger the rocket itself, the more fuel is required to bring the payload to near-earth orbit. This is a real vicious circle.
An artistic presentation of the future SLS booster
As rockets get bigger and biggertheir production and launch is becoming more expensive. And this is just one of the main problems of the new SLS rocket. Only one of its development over the past decade, NASA has spent more than 14 billion dollars. In this case, the carrier is still not ready. As soon as this happens, it is expected that the agency will be able to launch it no more than twice a year, since the cost of each launch will be about $ 1 billion. For comparison, the launch of a private carrier of a heavy class Delta IV Heavy costs about 350 million, and the launch cost of the same Falcon Heavy starts with an amount below $ 100 million. Even if both carriers are launched together, the cost will not even come close to the SLS launch price anyway.
In this regard, the use of space tugswill also allow NASA to save a lot of money in the future. For example, if the agency nevertheless decides to use a tug to deliver spacecraft to the Moon, then it can be returned back to near-earth orbit and simply left there. When it is needed again - just refuel and reuse.
Assembly in space
Of course, for this approach to work, NASAIt is necessary to develop a new docking system with such tugs. At the Senate hearing, the head of the agency, Jim Brydenstein, said that in its current form, the Orion capsule does not have the technical capabilities to dock with space tugs, “therefore, from now until June 2020, NASA will need to develop a docking system ".
Still, the technology that will be neededfor the implementation of such a system - are not new. For example, the Russian Soyuz spacecraft, which is being delivered by new crews to the ISS, have been using the automatic docking system for a long time. As part of the first test launch of the Crew Dragon spacecraft, SpaceX also demonstrated the ability to dock with the station in automatic mode, using a system of sensors and lasers to safely approach the ISS docking gateway.
"LIDAR system and machine vision technology,which were used by the Crew Dragon spacecraft for automatic docking with the ISS - these are the technologies and equipment that can be assembled and installed on spacecraft directly in space, ”says Andrew Rush, head of Made In Space, who developed a 3D printer for printing in microgravity, which was tested on board the ISS.
The first docking of the SpaceX spacecraft Crew Dragon from the ISS, held on March 4, 2019
There is another option that will simplify the task ofthe withdrawal of heavy spacecraft into orbit. At least in the future. The question of the need to use large missiles could be solved by assembling equipment in parts directly in space. Instead of sending some bulky equipment in one launch, it would be easier to make several space launches of smaller payload missiles (and cost) with several payloads, and then put all the pieces together in orbit. The same approach (at least partially) could be used in the assembly of spacecraft. In addition, NASA has already faced the problems of assembling very large spacecraft and their location inside the rocket. Take at least the same space observatory of the new generation of “James Webb”, which does not quite fit into the launch vehicle, which will have to deliver it to space. The device turned out so large and complex that it would have to be launched inside the PH when folded, and then deployed in space for two weeks. And if something goes wrong, the telescope may not work at all, putting an end to a project worth almost 10 billion dollars, which in fact does not even have time to begin.
When it is possible to assemble spacedevices directly in space, as well as the use of technology of additive production, there is no need for the initial assembly of vehicles on Earth.
"Distributing the load on several starts, andthen using space production and assembly technologies, we could really create space vehicles in a more profitable way from an economic point of view, ”says Rush.
Risks and difficulties
All these changes will certainly require their price. And not only financially. Automatic docking and assembly in space, according to Brydenstein, still carry too big risks for NASA.
"Using a special docking systemmanned spacecraft in orbit with the prospect of further movement towards the moon adds undesirable complexity and risks of a future mission, ”the head of the agency wrote in an open address to NASA staff.
In addition, the launch of equipment in parts and itsFurther assembly in space for only one mission implies multiple missile launches, with which some state officials responsible for these missions may not agree. According to some experts and officials, multiple launches increase the risks of a complete failure of the mission - if one of the launches fails, the whole mission will be at risk.
The use of commercial launch vehicles is alsowill not necessarily solve all the problems. Currently, engineers are testing the Orion spacecraft using computer simulations based on the current design of the SLS launch vehicle. In order to change the vector in the direction of commercial launch vehicles, they will have to postpone this work and begin to conduct new simulations with regard to new commercial launch vehicles. In addition, this will completely change the timeline of the flight, which in turn will require additional time to prepare. To do all this in a year and have time for the planned launch is an impossible task.
"When changing the flight plan, that will inevitablygiven the fact that all commercial media are not compared with SLS, almost all the work that was done before will be useless. In that case, Orion’s launch in June 2020 is out of the question, ”one of Lockheed Martin employees working on the Orion spacecraft commented The Verge anonymously.
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