Root Cause Classification of Breakup Events 1961-2018

This paper uses the updated NASA History of On-Orbit Satellite Fragmentations 15th Edition, to examine and categorize the root cause of historical breakup events to the greatest degree possible. Classes of debris progenitors have evolved, as many classes of Cold War-era spacecraft are now extinct, only to be replaced by new classes of payloads and rocket bodies statistically likely to experience debris-producing events. The efficacy of international debris mitigation implementation and root cause/fault tree analyses and lessons learned is examined in relation to the breakup of satellite classes or specific events. In select cases, the remaining on-orbit inventory of specific classes is identified in the context of possible future events. The environmental impact of these specific classes is examined and compared to nominal space environment projections. When appropriate, recommendations for debris remediation are made for specific satellite classes

An 82 Inclination Debris Cloud Revealed by Radar

The statistical debris measurement campaigns conducted by the Haystack Ultrawideband Satellite Imaging Radar on behalf of the NASA Orbital Debris Program Office are used to characterize the long-term behavior of the small, low Earth orbit (LEO) orbital debris environment. Recent analyses have revealed the presence of a persistent LEO small debris cloud, which has no accompanying large component, cataloged by the U.S. Space Surveillance Network. This cloud, at an inclination of approximately 82 and below 1200 km in altitude does, however, correspond to the heavily trafficked region of space that has suffered several known, accidental collisions, e.g., Cosmos 1934 and Cosmos 2251. In this paper, we describe the observed cloud and model it using the NASA Standard Satellite Breakup Model. Key features of the cloud model, including source attribution and debris mass constraints, are presented to enable further observations and characterization

Orbital Debris Quarterly News

No abstract availabl

The Updated GEO Population for ORDEM 3.1

The limited availability of data for satellite fragmentations and debris in the geosynchronous orbit (GEO) region creates challenges to building accurate models for the orbital debris environment at such altitudes. Updated methods to properly incorporate and extrapolate measurement data have become a cornerstone of the GEO component in the newest version of the NASA Orbital Debris Engineering Model (ORDEM), ORDEM 3.1. For the GEO region, the Space Surveillance Network (SSN) catalog provides coverage down to a limit of approximately 1 m. A more statistically complete representation of the GEO population for smaller objects, which can pose a high risk to operational spacecraft, is thus dependent on dedicated observations by instruments optimized to observe debris smaller than the SSN cataloging threshold. For ORDEM 3.1, optical data from the Michigan Orbital DEbris Survey Telescope (MODEST) provided the input for building the GEO population down to approximately 30 cm (converting absolute magnitude to size). For smaller sizes, the size distribution of debris in the MODEST dataset was extrapolated down to 10 cm, and orbital parameters were estimated based on the orbits of the larger objects. When compared to previous versions of the model, significant improvements were made to the process of building the GEO population in ORDEM 3.1, both in the assessment of fragmentation debris in the data and assignment of orbital elements within the model. A so-called debris ring filter, based on a range of angles between an orbits angular momentum vector and that of the stable Laplace plane, was applied to the data to reduce biases from non- GEO objects, such as objects in a GEO-transfer orbit. In addition, a new approach was implemented to assign noncircular mean motions and eccentricities to the fragmentation debris observed by MODEST because the short observation window (5 min) in GEO limits orbit resolution to a circular orbit assumption for assigning orbital parameters. For ORDEM 3.1, non-circular orbital elements were assigned using relationships that were identified between mean motion and the angle between the orbit plane and the stable Laplace plane, as well as between mean motion and eccentricity, based on breakup clouds modeled by the NASA Standard Breakup Model. This approach has yielded a high-fidelity GEO model that has been validated with data from more recent MODEST observation campaigns

Orbital Debris Quarterly News

No abstract availabl

Orbital debris environment for spacecraft designed to operate in low Earth orbit

The orbital debris environment model is intended to be used by the spacecraft community for the design and operation of spacecraft in low Earth orbit. This environment, when combined with material-dependent impact tests and spacecraft failure analysis, is intended to be used to evaluate spacecraft vulnerability, reliability, and shielding requirements. The environment represents a compromise between existing data to measure the environment, modeling of this data to predict the future environment, the uncertainty in both measurements and modeling, and the need to describe the environment so that various options concerning spacecraft design and operations can be easily evaluated

The NaK Population: A 2019 Status

The statistical debris measurement campaigns conducted by the Haystack Ultrawideband Satellite Imaging Radar (HUSIR) on behalf of the NASA Orbital Debris Program Office are used to characterize the long-term behavior of the small, low Earth orbit (LEO) orbital debris environment. A long-recognized, unique component of the LEO environment is composed of small Sodium-Potassium (NaK) eutectic nuclear reactor coolant droplets associated with the Soviet Radar Ocean Reconnaissance Satellite (RORSAT) program. Beginning with the flight of Cosmos 1176, RORSAT vehicles would nominally separate their reactor core at end of mission, thereby venting the NaK coolant and producing the NaK droplet population. In this paper, we describe the methodology by which NaK are segregated from the statistically sampled general debris population and their sizes inferred; the current NaK environment; how it has changed over time; and a potential new source of NaK: RORSAT vehicles that did not separate their reactor core by either design or apparent malfunction

Recent Results from the Goldstone Orbital Debris Radar: 2016-2017

Since 1993, the NASA Orbital Debris Program Office has used the Goldstone Orbital Debris Radar (Goldstone) to sample statistically the orbital debris environment. Due to the sensitivity of this radar, which can detect an approximately 3 mm-diameter conducting sphere at 1,000 km, it has filled an important role in the characterization of the sub-centimeter-sized orbital debris population. Through the years, the capabilities of this system have increased recent updates include increased receiver bandwidth and a change in the bi-static observation geometry both of which enhance the radars ability to estimate orbital parameters. In 2016, dual polarization capability was added, making this the first year where both right- and left-hand circularly polarized information was available from this sensor. This additional polarization information may enable better characterization of sub-centimeter-sized particles in low Earth orbit, particularly since the receiver triggers on reflected energy from both left- and right-handed circular polarizations independently. In this paper, we present measurements and results derived from data taken during the calendar years (CY) 2016-2017 by Goldstone and compare this dataset to measurements taken by the Haystack Ultra-wideband Satellite Imaging Radar (HUSIR) during a similar timeframe

Orbital Debris Quarterly News

The Indian spacecraft Microsat-R (International Designator 2019-006A, U.S. Strategic Command [USSTRATCOM] Space Surveillance Network [SSN] catalog number 43947), launched on 24 January 2019, was intentionally destroyed in a test of a ground-based, direct-ascent Anti-Satellite (ASAT) weapon system at 0640 GMT on 27 March 2019. At the time of breakup the 740 kg spacecraft was in an approximately 294 x 265 km altitude, 96.63 orbit. A total of 101 debris have entered the public satellite catalog (through object 2019-006DF), of which 49 fragments remain on-orbit as of 15 July 2019. However, over 400 fragments were initially tracked by SSN sensors and cataloging is complicated by the low altitude of the event and the concomitant rapid orbital decay. A Gabbard plot of this debris cloud is presented in the figure on page 2. A Centaur V Single-Engine Centaur (SEC) rocket variant (International Designator 2018-079B, SSN number 43652) fragmented in early April 2019. At the time of the event the stage was in an approximately 35,092 x 8526 km altitude, 12.2 orbit. This Centaur V upper stage is associated with the launch of the USA 288, or Advanced Extremely High Frequency 4 (AEHF 4), spacecraft from the (U.S.) Air Force Eastern Test Range on 17 October 2018. The cause of the event is unknown. No debris have entered the catalog at this time, but the ODQN will provide updates should they become publicly available