Rescue from interception and excessive cost. Potential and prospects of the DARPA DRACO program
The Advanced Development Agency DARPA continues to search for technologies to increase the survivability and stability of the military orbital group. The most ambitious proposal in this area involves the creation of a DRACO nuclear propulsion system for satellites, with which they can maneuver and escape from under attack. This concept looks very interesting, but it has both advantages and disadvantages.
Perspective development
The new DRACO (Demonstration Rocket for Agile Cislunar Operations) program was launched about a year ago. General plans for carrying out certain works were drawn up, as well as key requirements and project technologies were identified. In addition, the search for performers began.
In September 2020, DARPA signed an agreement with Gryphon Technologies. Over the next few years, it will have to provide scientific and technological support to the developers of the DRACO engine. The value of the signed contract reached $ 14 million.
In April of this year, plans for the near future became known; also new agreements were concluded with the contractors. In the next 18 months, it is planned to carry out design work, divided into two directions - Track A and Track B. The goal of "Track A" is to develop a new nuclear rocket engine. As part of the parallel project "B", they will work out the appearance of an "operational" spacecraft for such an engine (Operational System - OS), and also create a technology demonstrator (Demonstration System - DS).
General Atomics was appointed as the executor of the Track A project; she will be assisted by Gryphon Technologies, previously involved in the program. Spacecraft development was entrusted to Lockheed Martin and Blue Origin. All program participants will constantly interact with each other and exchange technical and other information.
In June, another company, Ultra Safe Nuclear Technologies (USNC-Tech) from Ultra Safe Nuclear Corporation (USNC), joined DRACO. Its task will be to help with the development of both "tracks" in the context of the safety of the propulsion system and related systems.
Thus, the final list of program participants has been determined and real research and design work has begun. They are planning to spend several years and hundreds of millions of dollars on them. The first flight of the DRACO-powered DS demonstrator is scheduled for 2025. As previously reported, a chemical-powered launch vehicle will launch DS into orbit, where the propulsion system will be tested. It is not known how soon new technologies will be able to be brought to the stage of OS and implementation in practice.
New guidelines
The goal of the DRACO program is to create a nuclear propulsion system of the NTP (Nuclear Thermal Propulsion) type. The architecture and principle of operation of such an engine is well known, however, DARPA has not yet published the terms of reference and the exact characteristics of the future product.
The core element of the NTP / DRACO engine is a nuclear reactor of the required power. Reportedly, the reactor will use uranium with an enrichment level of 5-20%. (so-called HALEU - High Assay Low Enriched Uranium). The heat from the reactor will be used to heat the working fluid, which will become liquefied hydrogen or another substance. The liquid will vaporize, gain additional energy, and flow out through the nozzle at a high speed to provide the required thrust.
It is estimated that an NTP engine using hydrogen will be approximately twice as efficient and economical as a chemical engine in terms of overall performance and capabilities. This will provide known benefits in the development and operation of spacecraft. In particular, it will be possible to reduce the tanks for hydrogen "fuel" and reduce the total mass of the ship.
The main goal of the DRACO project is to improve the safety of military spacecraft in low orbits. Developed countries, viewed as likely adversaries to the United States, have or are developing anti-satellite weapons. Accordingly, in the course of a full-scale conflict, the Pentagon's orbital group runs the risk of quickly losing at least part of its equipment and capabilities.
The main result of the DRACO project should be a universal nuclear propulsion system suitable for mounting on spacecraft for various purposes. With its help, it is proposed to withdraw satellites from the strike of anti-satellite missiles or interceptors.
The principle of such protection is quite simple. When an attack is detected, the nuclear engine will have to quickly transfer the device to another orbit, incl. higher, out of reach weapons enemy. After the threat disappears, DRACO will be able to return the device to its former orbit. High efficiency in terms of nuclear fuel and working fluid will make it possible to perform such maneuvers more than once.
Project potential
At the level of key ideas and concepts, the DRACO program looks quite interesting and promising. At the same time, it is obvious that the development of all the necessary components will be associated with serious difficulties and will be quite expensive. Time will tell whether it will be possible to overcome all expected and sudden difficulties and fulfill all plans.
The idea of using an economical propulsion system to remove a satellite from impact has high potential and is of great interest. Existing and promising anti-satellite missiles and interceptor vehicles are designed to destroy orbital targets on a known trajectory, which allows you to calculate the lead point.
A sudden change in the parameters of the target's orbit will, at a minimum, reduce the effectiveness of such a weapon. The enemy will have to launch new means of interception, the successful use of which is also not guaranteed. Also DRACO will be able to raise the satellite above the interception line - this will make any missiles and combat spacecraft useless.
However, obtaining such opportunities is associated with a number of difficulties of various kinds. First of all, it should be borne in mind that engines of the NTP type, suitable for integration into rocket and space technology, still exist only at a theoretical level. Companies General Atomics, Gryphon Tech., USNC-Tech and others have yet to find all the necessary technologies and create a full-fledged working engine.
It should be noted that DARPA is showing some optimism and plans to conduct the first OS / DRACO orbital flight as early as 2025. This may indicate the completion and successful completion of part of the research work. Based on their results, the development of a full-fledged project will begin. Despite the complexity of the tasks, the program participants still have enough time before the specified deadlines.
The DRACO program, like many other promising projects, may face financial problems. The exact cost of developing a fundamentally new engine and related products has not yet been determined, although it is already clear that we are talking about hundreds of millions or billions of dollars. The high cost, combined with the complexity and technical risks, can lead to the most severe criticism or even the closure of the project.
Completing the development and testing of DS and OS with a DRACO product does not guarantee complete success either. A promising nuclear facility is being developed for use on spacecraft. How much will the serial engines cost and how they will affect the cost of updating the orbital constellation is a big question.
In the distant future, DRACO developments can find application in various areas of the rocket and space industry, where compact and economical propulsion systems are required. However, such prospects for the whole direction directly depend on the results of the current project. If it does not suit the military and the congressmen, it should not be surprising that civilian astronautics will also abandon nuclear engines.
With an uncertain future
As befits the organization of promising developments in the defense sector, the DARPA agency is again trying to create a full-fledged nuclear rocket engine, moreover, for solving specific problems and with an eye to use in real projects. The proposed ideas are of great interest and the new project is indeed capable of creating a large reserve for the future, when anti-satellite weapons become a real and serious threat.
However, the successful completion of the DRACO program is still in question. It faces very complex tasks, the solution of which is unlikely to be quick, inexpensive and simple from the point of view of science and technology. Accordingly, the program risks facing delays, lack of funding and other problems. Whether it will be possible to meet all the deadlines, meet the budget and create equipment with the required characteristics - it will become clear over the next few years.
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