Rocket Body Research Articles

Quality Diagnosis for Rocket Body Structure Manufacturing Process Based on Product Quality DNA

ABSTRACTIn the current multivariety and small‐batch production mode, it is difficult to fully reflect the evolution law of the sampling population due to incomplete sample information in the manufacturing of the rocket body structure. By referring to the principle of biological DNA, a knowledge‐based quality diagnosis strategy is adopted, and a quality diagnosis method for the rocket body structure manufacturing process based on product quality DNA is proposed in this paper. The accumulated experience or knowledge in the past is stored in the product quality DNA knowledge base in the form of cases. Through knowledge retrieval, historical cases with the highest similarity to the product quality DNA to be diagnosed are found, and reasonable control and rectification schemes are provided for the quality problems in the production process, so as to avoid the same quality problems in the future. The feasibility of the method is verified by two case studies of two welds. The results show that the method can effectively and accurately diagnose weld quality.

Quality prediction for rocket body structure manufacturing process based on improved ELM

In the current multi-variety and small-batch production mode, this paper proposes a quality prediction method for rocket body structure manufacturing process based on improved extreme learning machine (ELM). Aiming at the non-optimal problems caused by random selection of input layer weights and hidden layer bias of ELM, particle swarm optimization (PSO) is combined with gravitational search algorithm (GSA) to form a hybrid algorithm to optimize the random parameters of ELM. Taking a weld in a rocket body structure as an example, the weld width prediction model based on improved ELM is established and verified. The results show that compared with the prediction model based on the standard ELM and the prediction model based on PSO-ELM, the prediction model based on improved ELM has higher prediction accuracy, and its prediction deviation does not exceed 2.5%, which can effectively predict the weld width.

Computer Vision Based Areal Photographic Rocket Detection using YOLOv8 Models

Advances in aerospace engineering and aerodynamics have pioneered space exploration and helped support telecommunication infrastructure. But these same developments have also aided in the creation of weapons of devastating impact. This necessitates the development of ways for detecting and tracking rockets. While several methods, mostly based on Doppler radar exist, the need for active radio emissions limits the applicability of these systems. A passive system has several advantages over traditional techniques, however their potential is largely unexplored. This work seeks to tackle this research gap by exploring the potential of emerging computer vision townies applied to rocket detection and tracking. The advantages of such a system are the relatively low cost as well as passive nature making observation stations harder to detect and easier to deploy. This work explores the potential of pre-trained, lightweight YOLOv8 architectures for rocket detection in real-world situations. A publicly available dataset is utilized and a comparative analysis is carried out between nano and small models. Both models demonstrate favorable outcomes with an accuracy of 0.90 for rocket body detection and 0.93 for engine flame detection. Nevertheless, rocket detection into space is still difficult, with a precision of 0.64 for this class. This paper indicates areas for additional refinement and demonstrates the potential of computer vision technology in passive rocket detection.

Context and perspectives of sub-orbital activities and transit through airspace/ground support activities

This paper provides some considerations on the current context and perspectives concerning the sub-orbital activities and transit through airspace/ground support activities issued in the frame of the IAF-IAA-IISL Working Group on Space Traffic Management (STM). The group brought together experts from different backgrounds and countries in order to analyze the different aspects of these activities, namely, technically, programmatically, and legally.The rise in space activities, both orbital and suborbital, increases the number of possible interactions with national airspace, inducing potential problems of traffic management. Spacecraft transiting through airspace (both international and national) involve different objects (satellites, launch vehicles, rocket bodies, suborbital vehicles, aircraft …) and missions with varied associated risks. These risks can be generally characterized by the time in airspace, the velocity of spacecraft, and its altitude. Despite the increase in space activities, there are currently no binding international rules specific for spacecraft traversing through airspace. However, there are guidelines, national frameworks, recommendations from organizations (e.g. UN-COPUOS, OSI) covering part of the interaction of space activities and transit through airspace. Additionally, some may argue customary international law exists in the current practice of preventing fallout during launch/re-entry activity into sovereign airspace.The rising number of spaceports, both for orbital and suborbital missions, contribute to increase of space traffic in terms of location of the launch sites and of widespread type of launch and re-entry missions.The working group focused on the identification of the objects to be considered for this interaction, the current available rules and guidelines, the recommendations issued by specific organizations on the subject, and the experts’ advice in order to have a global view of the context and summarize some general recommendations for future operations.

Infrared photometry and spectrometry of satellites and debris at UKIRT

The characterization of deep space debris poses a significant challenge in Space Domain Awareness (SDA). Multi-color photometry and the resultant color indices offer the potential to rapidly discriminate between debris and intact space objects such as rocket bodies and satellites. These multi-color techniques can also identify anomalous members of objects in certain groups and cue higher fidelity data collections and studies. However, multi-color photometry can be difficult to interpret, as the effects of phase and rotation become conflated with the more fundamental material properties of the satellite. Additionally, the broad astronomical photometric bands may not identify key spectral features that can be diagnostic for SDA applications. With our recent observational campaign we have been able to collect 5-color photometry in the near-IR with WFCAM as well as overlapping near-IR spectra with the UKIRT 1–5 μm Imager-Spectrometer (UIST). On a small set of objects, we also have mid-IR spectrophotometry with the Mid-IR esCHELLE (Michelle) imaging spectrograph.Our previous measurements with the United Kingdom Infrared Telescope (UKIRT) Wide Field Camera (WFCAM) characterized a wide range of space objects with the goal of developing techniques to rapidly discriminate between different classes of objects and to identify anomalous members of these groups. The survey has produced a comprehensive database of 5-color photometry in the Z, Y, J, H, and K bands, analogous to the bands that are anticipated to be exploited by future U.S. ground-based SDA systems. Our current data set includes:(a)United States Centaur rocket bodies (RBs),(b)Molniya communication satellites including the −1 K, 1T, −2, and −3 variants,(c)Russian FREGAT and SL-6 upper stage RBs in Molniya orbits,(d)Russian Breeze-M rocket bodies disposed of in GEO-crossing graveyard like orbits, and the Angara-5/Breeze-M mass simulator, also disposed of in a near-GEO orbit,(e)Intact payloads selected from satellites using the Boeing HS-376 buses—including four different generations of solar panel technology.Many of the objects we have studied have significant orbital inclination or drift in the GEO belt. The interpretation of photometry of these objects is especially difficult as phase angle can no longer be considered simply as a single-dimensional quantity. During 2023, we have endeavored to expand our phase angle coverage of a handful of objects and comprehensively sample brightness and color in both components of phase angle. In this paper we present exemplary “phase-phase” diagrams demonstrating this technique and highlight some of the practical and observational difficulties in achieving comprehensive phase angle coverage and interpreting these results.

Determination of the spacecraft’s spin axis orientation. Photometric patterns method

Near-Earth space is becoming increasingly congested; the number of satellites in low Earth orbit (LEO), where there is already the greatest spatial density of objects (including man-made debris), is increasing rapidly. Knowing the status of non-cooperative space objects is one of the requirements of space situational awareness (SSA). Assessing the dynamic properties of large inactive satellites and rocket bodies, such as their rotation period and the spatial location of the rotation axis, is necessary to predict their orientation. This information is critical to both the success of active debris removal (ADR) missions and improved orbital propagation of objects in LEO. Monitoring the state of RSO is carried out by various means, including using ground-based optical sensors by collecting photometric data, processing it and analyzing light curves. This paper presents a new method for estimating the orientation of the RSO rotation axis in space. This method relies on structural analysis of RSO light curves and the search for similar fragments, called ”photometric patterns,” in observations obtained from one or several sites simultaneously or over a short period of time. The method does not require knowledge of the RSO shape and does not impose strict requirements on the quality of photometric observations.

Uncontrolled reentries of space objects and aviation safety

There is a growing risk to aircraft in flight from collisions with debris produced by the breakup of uncontrolled rocket bodies and satellites during atmospheric reentry. On one hand, the aviation industry has grown to almost 39 million flights per year, with a 63 % increase between 2004 and 2019. On the other hand, the number of successful rocket launches more than doubled between 2015 and 2023, from 87 to 212, respectively. During those 212 launches in 2023, 128 rocket bodies were abandoned in orbit, left to reenter uncontrollably. Such uncontrolled space object reentries are hard to predict, making mitigation measures difficult. In November 2022, a reentering Long March 5B rocket caused the closure of airspace over Europe, delaying 645 flights and having a plausible economic impact of millions of Euros. There are international and domestic laws that might enable the recovery of economic losses resulting from uncontrolled reentries, but such losses should not be allowed to occur in the first place. Instead of leaving the location of a reentry to chance, controlled reentries can be achieved with existing technologies and mission designs, directing reentries away from areas of high aircraft traffic. Moving to a controlled reentry regime would create a cost to space operators – but that cost is currently being externalized to the aviation industry. Multilateral solutions to create a controlled reentry regime should be pursued, as recommended in the 2023 Montreal Recommendations on Aviation Safety and Uncontrolled Space Object Reentries, before there is a tragedy caused by an aircraft collision with debris from a rocket body or satellite.

Rolling active load relief technology for launch vehicle bundled with common booster core in face

The aerodynamic interference forces and moments of different windward surfaces of a launch vehicle bundled with a common booster core in the face vary considerably. The servo mechanism is laid out to maximize the control capability of the rocket at a certain angle. The dominant surface of the rocket is determined by aerodynamic interference and control capability. For the problem of large interference and asymmetry during the flight of a nominal rocket, a rolling active load relief control law based on the optimization of the spatial interference vector is proposed. The direction with the largest spatial interference vector is obtained online by visual acceleration information. By adjusting the rolling program angle, the rocket will align the dominant face with the direction of the largest interference when flying through the windy area. And then, the rocket obtains a good control effect. The simulation results show that the control law proposed in this paper can effectively improve the adaptability of the rocket control in the case of sudden changes in wind direction. It achieves the purpose of reducing the static load of the rocket body structure during the flight.

Space activity and environmental quality

ABSTRACT Space exploration has gained momentum over the last few decades. But what are the environmental impacts of space activity? While climatologists have a keen interest in this question, economic research into it is limited. In this paper, we investigate the impact of U.S. space activity on the quality of the environment. We apply the two-stage least squares method to time series data collected between 1981 and 2021. The results indicate that objects, payloads, and rocket bodies launched into space degrade the quality of the environment. Specifically, the results show that the launch of objects into space has a positive impact on footprint levels, CO2 footprint levels, non-CO2 footprint levels, global temperature, CO2 emissions, and greenhouse gas emissions. These results are corroborated by payloads and rocket bodies activities in space. Overall, the results suggest that objects, payloads, and rocket bodies increase demand for natural resources, contribute to climate change, and increase pollution.

Satellite Visibility During the 2024 April Total Eclipse

On 2024 April 8, tens of millions of people across North America will be able to view a total solar eclipse. Such astronomical events have been important throughout history, but with nearly 10,000 satellites in orbit, we question whether total eclipses will now reveal a sky full of satellites, fundamentally changing this experience for humanity. Using the current population of Starlink satellites, we find that the brightest satellites would be naked-eye visible in dark skies, but the high sky brightness during totality will make them undetectable to the unaided eye. Our model does not take into account the effects of chance reflections from large, flat surfaces like solar panels, which we expect will cause glints and flares that could be visible from large satellites and abandoned rocket bodies. Time-lapse all-sky imaging might reveal satellites during the eclipse.

Challenges in Identifying Artificial Objects in the Near-Earth Object Population: Spectral Characterization of 2020 SO

Since the dawn of the Space Age, hundreds of payloads have been launched into heliocentric space. As near-Earth object (NEO) surveys search deeper for small asteroids, more artificial objects in heliocentric orbits are being discovered. We now face a challenge to identify the true nature of these objects and avoid contaminating the NEO catalog. Here, we present the methods used to characterize one such object. 2020 SO was discovered by the Pan-STARRS1 survey on 2020 September 17. Originally classified as a NEO, the object’s artificial nature became evident due to its low velocity relative to Earth and solar radiation pressure affecting its orbit about the Sun. Based on a backward propagation of its orbit, 2020 SO is thought to be a Centaur rocket body (R/B) from the launch of the Surveyor 2 mission to the Moon. We characterized 2020 SO using a range of ground-based optical and near-infrared telescopes to constrain its true nature. We find that its reflectance spectrum is consistent with that of other Centaur R/B launched during a similar time frame, and we identify 1.4, 1.7, and 2.3 μm absorption bands consistent with polyvinyl fluoride used on the aft bulkhead radiation shield exterior of Centaur-D R/B at the time.

Multiband photometric observations of GEO objects through Sloan filters

With the precipitous growth of the population of objects in Earth's orbit, all major space agencies and companies have made space surveillance a priority to ensure the safety of space missions. With the application of the methods of space surveillance, this article aims to characterize the population of objects in the Geostationary Earth Orbit (GEO) using optical measurements across multiple spectral bands. The study takes place in a context in which the existence of space debris poses a continuous hazard to the operations of active satellites in GEO. Photometric observations of GEO objects using Sloan filters were obtained with SCUDO, a small-aperture telescope part of the Sapienza network. Observations are divided into categories, including 11 objects: rocket bodies (4), defunct satellites (3), and active satellites (4). The spectral response of these objects has been analyzed leading to the identification of a photometric signature which was repeated for two Eutelsat satellites observed under same conditions. All the observed targets resulted in a lower magnitude in the near-infrared. Color indexes also indicate that they are redder than the Sun. This is particularly evident for SL-12 rocket bodies, whose g’-z’ reaches 1.5.

Density-based evolutionary model of the space debris environment in low-Earth orbit

Lethal untrackable debris objects pose the highest risk to the sustainability of the space environment, and thus, shall be included in the assessment of the long-term effect of mitigation and remediation measures to the space debris problem. The introduction of centimetre-sized particles in the debris evolutionary models represents a challenge from a computational cost point of view. To answer this need, this work proposes a novel probabilistic debris environment propagator. The method classifies the objects population into intact objects and fragmentation debris. The evolution of the former population is retrieved through an individual definition of each object’s mission profile. A continuum approach is adopted for the characterisation of the fragments, whose density distribution in orbital elements is propagated in time through the continuity equation. The intrinsic computational efficiency of the density-based fragments cloud models is leveraged to make the method agnostic to the lowest fragments size considered. A second classification of the population of intact objects into species, such as payloads, rocket bodies, mission related objects and constellations, ensures a faithful replication of their orbit evolution. Fragmentation debris caused by intact objects explosion and accidental fragments-intact object collision are included in a probabilistic fashion at the detected fragmentation epoch, to account for their feedback effect onto the environment. The model is applied to estimate the evolution of the space debris population in low-Earth orbit up to 200 years from the reference epoch, with and without the inclusion of a future launch traffic pattern, and considering a different fulfilment of the post-mission disposal phase.

Bending of sheets and profiles on a four-roll machine for rocket bodies, pipe and frame products. Part 13

A theory of stamping is developed taking into account the anisotropy and hardening of the workpiece. The parameters of the strain-stress state of the workpiece are calculated using the example of bending a conical tube on a rolling machine or in a die. CAD/CAE modeling is used to study deformations, stresses and forces acting on the workpiece from rolls or die tools. The criteria for the formation of cracks, low accuracy and excessive springback of the part after processing are determined, and recommendations for their elimination are given. Keywords:stamping, workpiece, anisotropy, bending of a conical tube, rolling machine, die, CAD/CAE modeling dr_zharkov_v_a@mail.ru

Service load analysis and ply stacking optimization for composite tool of aerospace cryogenic tank

AbstractThe integrated manufacturing of aerospace composite cryogenic tanks is crucial for enhancing payload efficiency, reducing costs, and leading the aerospace industry upgrade. Composite segmented tool, which balances internal support and mold surface, must not only meet the requirements of disassembly and demolding but also ensure sufficient stiffness without deformation under loads like winding tension and curing shrinkage during tank formation. This article addresses the challenge faced by composite tool with uniformly thick ply stacking schemes, where the weight increases significantly with the rocket body diameter, rendering functions such as disassembly and demolding unfeasible. A global–local optimization approach aimed at achieving variable‐thickness ply stacking designs for composite tooling was proposed. Starting with a defined segmented tool design for the Φ3.35 m tank, models for calculating winding tension under complex service conditions and finite element models for curing shrinkage were established. Optimization of ply shapes, dimensions, and sequences using OptiStruct was conducted, which achieved a weight reduction of 34.48% while ensuring that deformations under loading met design standards. Subsequently, the engineering trials for the composite melon petal and wallboard corresponding to the Φ600 mm tank were conducted based on the optimized scheme. The maximum deformations for the two components were 0.43 mm and 0.15 mm, respectively, meeting the manufacturing requirements for engineering applications. The results provide a lightweight, high‐stiffness, and detachable tool design scheme for achieving the integrated manufacturing of extra‐large (Φ10 m) composite tanks.Highlights The external load was analyzed through theoretical and simulation approaches. The weight of composite tool was significantly reduced after optimization. The engineering prototypes of the segmented tools were achieved.

Improving casualty risk estimates for uncontrolled rocket body reentries

Approximately 70 % of launches in 2022 resulted in an uncontrolled rocket body reentry, creating an unnecessary casualty risk to people on the ground, at sea, and in aircraft. Rocket bodies have masses ranging from tens of kilograms to 20 tonnes. Using known rocket body masses and correlations between mass and casualty area, we present revised estimates for the expected risk, finding a 20–29 % probability of one or more casualties over the next decade.Some states use a 1-in-10,000 threshold for accepting an uncontrolled reentry casualty risk when approving a space activity. This threshold, which is not universally agreed upon, represents a risk acceptance by one country, but imposed on the world population. As the use of space expands, with a record 180 successful launches in 2022, states and other launch providers should adopt technologies and mission designs that ensure controlled reentries. Uncontrolled reentries, particularly of large rocket bodies, constitute an unsafe and unnecessary practice.

Effects of Orbit Raising and Deorbiting in Source-Sink Evolutionary Models

The sustainability of the low-Earth-orbit (LEO) environment is threatened by the growing number of anthropogenic space objects planned to be launched in the coming years. This paper investigates the evolution of objects residing in LEO through the MIT Orbital Capacity Assessment Tool (MOCAT), an evolutionary multishell, multispecies source-sink model. The proposed novelty considers the flow of objects crossing multiple shells during orbit raising and deorbiting maneuvers, modeled through the secular variation of the semimajor axis under a low-thrust continuous applied control. To this aim, a higher-fidelity MOCAT version, including active satellites, derelicts, debris, and rocket bodies, has been developed and used. The results demonstrate that incorporating orbit transfer fluxes into the model results in a higher number of collisions, which leads to a greater quantity of debris and poses a greater threat to the safety of LEO.

Serendipitous Detection of Orbital Debris by the International Liquid Mirror Telescope: First Results

Orbital debris presents a growing risk to space operations, and is becoming a significant source of contamination of astronomical images. Much of the debris population is uncatalogued, making the impact more difficult to assess. We present initial results from the first ten nights of commissioning observations with the International Liquid Mirror Telescope, in which images were examined for streaks produced by orbiting objects including satellites, rocket bodies and other forms of debris. We detected 83 streaks and performed a correlation analysis to attempt to match these with objects in the public database. 48% of these objects were uncorrelated, indicating substantial incompleteness in the database, even for some relatively-bright objects. We were able to detect correlated objects to an estimated magnitude of 14.5 and possibly about two magnitudes greater for the faintest uncorrelated object.

“Multispacecraft to Multidebris” Space Debris Removal Strategy Based on Target Allocation Method

The combination of increased amount of “space junk”, lack of precise tracking information and control of items orbiting Earth, and debris from past collisions posed important threats to human space missions. In this study, a strategy enabling “multispacecraft to multidebris” debris removal task is proposed. By analyzing the current distribution of space debris, 282 large debris and rocket bodies are selected as target database. The traditional-density-based spatial clustering of applications with noise algorithm is innovatively modified by defining the speed increment as threshold parameter for dividing target debris into different clusters. Then, the Hungarian-algorithm-based target allocation strategy is used to assign multispacecraft to different debris clusters for the removal mission. Simulations verify the effectiveness of the proposed “multispacecraft to multidebris” strategy that is able to remove as much as 83.33% of the total 282 target debris.

Long baseline bistatic radar imaging of tumbling space objects for enhancing space domain awareness

AbstractLong baseline bistatic radar systems herald enhanced sensitivity and metric accuracy for space objects in geosynchronous orbits and beyond. Radio telescopes are ideal participants in such a system; in particular, they often feature large apertures with low‐noise temperatures and have stable, synchronised clocks. Pairing radio telescopes with high‐power radars creates new methodologies for Space Domain Awareness. This paper describes long baseline bistatic measurements using the Millstone Hill Radar in the USA, the Tracking and Imaging Radar in Germany, multiple receivers of the enhanced multi‐element remotely linked interferometer network array in the United Kingdom, and the Westerbork Synthesis Radio Telescope in the Netherlands. The authors, a Research Task Group formed by the NATO Science and Technology Organisation Sensors and Electronic Technology Panel (SET‐293), performed novel bistatic and monostatic radar imaging experiments with real on‐orbit tumbling rocket bodies. These experiments on tumbling objects at near‐geosynchronous orbits highlight successful demonstrations of advanced bistatic Doppler characterisation across diverse imaging geometries. Specialised Doppler processing on tumbling targets, such as the Doppler superpulse algorithm, enables high‐fidelity rotation period estimation and determination of minimum target size.