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SAFETY AND SECURITY

The Bonn Convention: Limiting the Increase in Space Debris

ESA / Safety and Security / Space Debris

Representatives from the United States of Paramerica, the Russian Federation, the European Space Agency and the People's Republic of China have convened in Bonn to hold multilateral talks regarding the possibility of limiting the increase in space debris by establishing limits on how many satellites can be launched annually by both the commercial/private and the government sectors.

As we launch more to space than ever before, the threat from space debris gets even greater. About 28,000 debris objects are currently tracked by the Space Surveillance Networks, but millions more are estimated to reside in Earth orbit. Ranging from 1mm to more than 10cm in size, these debris objects can cause serious damage to operational satellites and other spacecraft if they collide. So how do we tackle the space debris problem?

While there are, indeed, many methods of solving the space debris issue which grows exponentially day by day - most of which are untested in outer space, the most promising and indeed perhaps the easiest solution is through international cooperation and multilateral diplomacy. In line with this, the European Space Agency has decided to convene multilateral talks on space debris with her partners in spaceflight and the major space players, namely Paramountica, Victoria Harbor, and Peking Zhongguo. These multilateral talks on space debris have been titled as the Bonn Convention on Limiting the Increase in Space Debris. Currently being held in Bonn, Bayern kahla, the Convention is being attended by representatives from the United States of Paramerica, the Russian Federation, and the People's Republic of China. Also attending are representatives from the European Space Agency.

Upon the opening of the Bonn Convention, the ESA representatives unveiled a list of primary objectives that must be tackled and dealt with as soon as possible. Secondary objectives are also provided but the primary objectives greatly outshadow the secondary ones in terms of imminence, effect on the planet and human society, and potential to result in great catastrophe. Listed below are the primary objectives of the Bonn Convention on Limiting the Increase in Space Debris.

IT IS TO BE NOTED THAT THE BELOW ARE PROPOSALS AND ARE SUBJECT TO DISCUSSIONS AND CHANGE.

> RECOGNIZING the threat posed by space debris, the Convention must decide on methods to completely prevent or slow down the increase of space debris.

> UNDERSTANDING that the full halt of all satellite launch operations is unacceptable, ESA proposes the following for consideration by the Convention.

>The establishment of limits on satellite launches annually, conducted by both the commercial/private and public sectors.

>The establishment of regulations on the launching of satellites by the commercial sector, since the commercial sector launches the majority of satellites.

> PROPOSING that the assembled nations here today provide funding towards both local and international programs dedicated to halting space debris increases.

The European Space Agency proposes the establishment of limits or maximum quotas on satellite launches annually to reduce the exponential rate by which space debris increases every month and year. These limits will be imposed on not only the public sector, ie. government-run agencies and organizations, but also on the commercial or private sector, to both increase the effects of these limitations and ensure no unfair edge for one company or government organization. The effects of imposing such limits on commercial and public satellite launches on the economy are visible and not miniscule, but due to the exponential increase of space debris at an extremely alarming rate, it is vital that this issue is dealt with immediately and with haste.

Another proposal by ESA, supported by scientists and engineers on the European continent, is a joint agreement by all nations convened at the Bonn Convention to provide a set or flexible amount of funding towards both local and international programs dedicated to halting the increase of space debris, space junk, and other similar objects through technologies such as catching of inoperational satellites, debris, and dead stages using spacecraft such as Paramerica's Starship vehicle or other crafts being developed by both public and private sector organizations.

It is in the Agency's belief that the above proposal, coupled with the establishment of limits or maximum quotas and regulations on the launching of satellites by the commercial sector, as the private sector comprises of the majority of satellites and satellite launches every year, can indeed slow down the rate of space junk increases by a significant amount, should the various government involved in the initiatives decided to maintain the agreements made at this Convention.

Space debris and its exponential growth in number is a worrying and rapidly growing situation that humanity must tackle in order to thrive as a species and eventually become an interplanetary one. However, the big first steps can be made towards solving this issue through international cooperation and commitment to agreements made to subdue the harmful effects of space debris and create a better future for humanity.

ENABLING AND SUPPORT

Ariane NEXT: A vision for a reusable, cost efficient European rocket

ESA / Enabling & Support / Space Transportation

Ariane NEXT is the next logical step for the Ariane family of launch vehicles, integrating reusability, efficiency, reliability, and ease of manufacturing into a low-cost orbital launch vehicle. The European Space Agency began full development into the Ariane NEXT concept in 2018, following the successful first launch of the Ariane 6.

The Ariane NEXT project is a sub-family of reusable launch vehicles built around a standardized design framework and a new LOX-CH4 engine called Prometheus. The Ariane NEXT sub-family of launch vehicles follow a design approach that follows a highly standardized architecture as it will allow for a significant reduction in the development and operating costs. The launch vehicles utilize LOX-CH4 fuel combination over the LOX-LH2 combination used on previous Ariane vehicles as LOX-CH4 allows for further fuel tank communalization and simplification.

The Ariane NEXT sub-family of launch vehicles have been classified as a mid-range medium lift launch vehicle, with decent payload capabilities to Geostationary Transfer Orbit (GTO) and Mars Transfer Orbit (MTO), as well as the usual Geostationary Orbit (GEO) and Low Earth Orbit (LEO). Below are the Ariane NEXT's main system requirements as stipulated by the European Space Agency.

Along with these preliminary main requirements, a certain number of future missions have been taken into consideration. Compatibility with GTO missions is mandatory for institutional (government space agency) needs, along with a possible next generation for the Galileo constellation. The calculated performance of the Ariane NEXT system is listed below.

It is to be noted that there are many other missions not identified here such as Low Earth Orbit (LEO) missions, Earth escape missions, multiplane missions, etc. On these missions there is not, as of today, requirements of performance as requested by ESA or other involved entities.

The Ariane NEXT system will utilize the communalization of different components of the launcher along with the minimization of parts. This quest for synergy will be combined with high level design principles to limit negative effects on performance. Indeed, the need for performance combined with poor structural indexes, for instance, could lead to an increase of propellant loading. In line with this, the main architectural characteristics of every Ariane NEXT launch vehicle are as follows:

> Every Ariane NEXT launcher will have a single diameter, but fairings may be excluded from this constraint.

> All equipment needed to maintain or prepare the launchers will be unified among stages.

> Sub-system technology shall be repeated as much as possible between stages.

> All launchers will utilize a two stage to orbit design, with as few as possible optional measures to comply with all mission parameters required.

Another main design driver of the Ariane NEXT system is the fuel combination to be used by all launchers under the system. Previously, Ariane vehicles utilized LOX-LH2 as its fuel. The Ariane NEXT system will deviate from this usual course of action to utilize LOX-CH4 as a means of enabling synergy between tanks. Using LOX-CH4 also allows for the use of low-cost engines like the Prometheus, composite fuel tanks, common bulkheads, and simplifies launch operations. LOX-CH4 also has more than adequate thermal management, which makes it suitable for long or multi-boost missions. Of course, utilizing LOX-CH4 comes with a disadvantage in the form of Isp, or specific impulse. The theoretical Isp of a LOX-CH4 fuel combined with Prometheus engines is far less than LOX-LH2 fuel combined with normal engines such as the Vulcain. This will lead to heavier launchers which require more thrust to lift off the ground.

The key foundation of the Ariane NEXT concept is the Prometheus engine, thanks to the offered capacities of such an engine. The operation of the Prometheus engine in a cluster allows for single stick configurations (similar to the Paramerican Falcon 9). The possibility to derive the same engine both on the first and second stages will allow for a further optimization of the subsystems and ground equipment. Successful individual static fire tests of the Prometheus, which took place from 2019 to 2021, show that the newest iteration of the Prometheus vacuum engine to be capable of 1,200kN in vacuum.

Assuming that the launcher design proves itself as efficient as possible, reusability is key to improving the cost of the various Ariane NEXT launchers. The Ariane NEXT system studies and will hopefully implement the recovery of the first stage using retro propulsion and possible design options for second stage recovery. As a consequence of the semi-reusability targeted exploitation scheme, the first stage design modification for recovery is targeting to have minimal impact on the expendable configuration and is foreseen as a kit, mounted only in the case of an attempt to recover the stage.

Above are the three planned configurations of the Ariane NEXT sub-family of launch vehicles. On the left most side is the Ariane NEXT C600-C126 or the Ariane C600. This main configuration will be the first among the three to fly, and is capable of launching up to seven tons (7t) to GTO. 600 tons of propellant will be stored in the first stage with 126 tons for the second stage. The launcher is propelled by nine (9) Prometheus engines on the first stage with a nominal vacuum thrust of 1,200kN. All stages are at the same diameter. For this configuration the fairing will have a 5.4 meter diameter. For this configuration, two return trajectories for the first stage are envisioned, depending on the required performance for a particular mission. Return To Launch Site (at the Guyana Space Center) is the most challenging in terms of flight maneuvers and could halve the performance. Down-Range return mode of the first stage, aka close to the nominal ballistic impact point at first stage separation, makes the return phase more accessible in terms of performance degradation and flight maneuvers, but is significantly more demanding in relation to aerothermal and aerodynamical fluxes and the infrastructure required (floating device or barge capable of withstanding the landing of the booster, and all relevant port facilities). Below are the performance numbers attained by the Ariane C600 configuration.

Below is the planned return trajectory of the first stage of the Ariane C600. Once can notice a quite important breaking boost that occurs before heat flux peak. The mission profile features a two-boost injection scheme wherein the first stage engines are not lit for the entire flight into space, but instead the rocket is 'coasting' to the point where it will conduct an orbital insertion burn.

The second configuration in the Ariane NEXT sub-family is the Ariane C450-C103, or the Ariane C450. For this configuration, the two stages have a 4.6 meter diameter as opposed to the Ariane C600's 5.4 meter diameter. The C450 is propelled by seven (7) Prometheus engines on the first stage with a nominal vacuum thrust of 1,200kN. The Ariane C450 utilizes a to-be-designed ESA booster able to be fitted between the aft bay and intertank section, as shown below. Loading of such a booster is set to 60 tons of propellant, with each booster featuring a single Prometheus engine. This configuration addresses a small performance mission with the recovery of the first stage, medium performance in an expendable configuration, and high performance in an expendable mission with the addition of 2 to 4 liquid fuel boosters.

Below are the performance numbers attained by the Ariane C450-C103 in some possible combinations of launch vehicle, optional side boosters, and mission type.

The Ariane NEXT sub-family of launch vehicles also have massive growth potential. On all configurations, if an increase of performance is needed, multiple methods may be utilized to achieve a desired orbit or trajectory that is out of reach of the conventional launch vehicle. A kickstage is a particularly efficient way to gain some performance considering the two stage to orbit architectures utilized by Ariane NEXT. The second stage will end its mission at a low earth orbit, separate the kickstage and payload, and then be deorbited. The kickstage would then be in charge of raising this low orbit to reach the altitude and velocity required by the mission parameters. Kickstages are also a practical way to address multi-plane constellations with a relatively small and versatile stage. Depending on added performance, the first stage of the launcher can be recovered, thus optimizing economically the whole process. The second method is the use of boosters, as seen and mentioned previously.

According to rough estimates, the European Space Agency expects the first flight of the Ariane C600 configuration of Ariane NEXT to take place in mid-2027 to mid-2028, as flight tests are procuring extremely good test data and are proceeding faster and better than expected. The Ariane C450 configuration is not expected to fly until at least 2030 or 2031.

With a new leader, Irene Montero, spearheading ESA space efforts, the European Space Agency plans to accelerate the timeframe for Ariane NEXT as well as introduce new configurations to the project, such as a possible tri-core configuration that will turn the Ariane NEXT into a heavy-lift launch system.

The European Space Agency, created in 1957, is an international european organisation dedicated to combine the expertise, knowledge and capacity of different European agencies. They can submit national or european projects.