Arly Black, Purdue University; Carolin Frueh, Purdue University
Keywords: cislunar, SSA, fragmentation
Abstract:
Cislunar space, the region beyond the geostationary belt of near-Earth objects all the way up to the near-Lunar domain, has increasingly become of interest for mission designers and spacecraft operations. An increase in launches to this region heightens the risk of fragmentation events, through collisions, failed passivation of propellant tanks, battery explosions, or deterioration of aging or damaged spacecraft, among other causes.
Various studies of cislunar breakups have been performed, using, in some cases, versions of the NASA Standard Breakup Model (SBM) [1] and simulating assorted fragmentation events at distinct locations, such as select members of the Lyapunov or Halo orbital families [2, 3, 4]. This first series of papers showed impressively how widespread the impacts of a single collision can be and that fragments may easily migrate onto trajectories that interact with the near-Earth region, including Low and Medium Earth orbits and Geosynchronous orbits.
The challenge when evaluating breakup events in the cislunar region is that, even when employing the circular re- stricted three-body problem (CR3BP), which is considered relatively computationally inexpensive, and excluding other relevant forces such as solar radiation pressure and gravitational effects of Jupiter and the Sun, the parameter space is vast. Fragmentation events differ by: type and intensity; mass of the parent object; number, size, and energy of generated fragments; the trajectory or orbital family on which the event takes place (planar, non-planar, transfer, etc); and where on a given trajectory the event occurs, to name a few factors. Tremendous computational resources have been expended to even glimpse at a subset of possibilities in a single orbital family [3]. In turn, many of the relevant scenarios remain unexplored and no method so far exists to survey the parameter space or to extrapolate from a given set of initial conditions to a different, even neighboring, set of initial conditions.
In this paper, we introduce methods to utilize the dynamical structures in the CR3BP to classify and characterize the effects of fragmentation events a priori without extensive propagation. Techniques are established to constrain feasible regions of travel and predict viable fragment trajectories and locations for a given event. Through isolation of trajectories by Jacobi constant, employment of orbital family manifolds, identification of patterns in Poincare ? maps, and implementation of a modified version of the SBM, these methods provide a comprehensive characterization of breakup events in the cislunar region.
This work first examines constant Jacobi and delta-v cases to evaluate the range of travel opportunities for frag- ments with given initial conditions. Nearby orbital families are assessed for similar energy level ranges, and three- dimensional manifolds are produced as plausible pathways for fragmented objects. Additional cases employ the SBM to simulate more realistic fragmentation events with a broad range of energies and delta-vs, which are correlated to the earlier constant parameter cases. Modifications to the SBM include mass and momentum conservation, updates based on ESAs MASTER-8 debris environment model [5], and an optimizer designed to control the uniformity of breakup in an explosion. The results illustrates a priori the portion of fragments that will remain in the vicinity of their originating orbit, leave the direct sphere of influence of the CR3BP, or embark on Earth-bound trajectories. The application of Poincare ? maps provides insight into the available solution space of a given fragmentation event via a reduction in dimension, such that patterns in the motion are more easily visualized.
Date of Conference: September 19-22, 2023
Track: Cislunar SDA