# Z.J. Folcik's research while affiliated with Massachusetts Institute of Technology and other places

**What is this page?**

This page lists the scientific contributions of an author, who either does not have a ResearchGate profile, or has not yet added these contributions to their profile.

It was automatically created by ResearchGate to create a record of this author's body of work. We create such pages to advance our goal of creating and maintaining the most comprehensive scientific repository possible. In doing so, we process publicly available (personal) data relating to the author as a member of the scientific community.

If you're a ResearchGate member, you can follow this page to keep up with this author's work.

If you are this author, and you don't want us to display this page anymore, please let us know.

It was automatically created by ResearchGate to create a record of this author's body of work. We create such pages to advance our goal of creating and maintaining the most comprehensive scientific repository possible. In doing so, we process publicly available (personal) data relating to the author as a member of the scientific community.

If you're a ResearchGate member, you can follow this page to keep up with this author's work.

If you are this author, and you don't want us to display this page anymore, please let us know.

## Publications (10)

The goal of the Draper Semi-analytical Satellite Theory (DSST) Standalone Orbit Propagator is to provide the same algorithms as in the GTDS orbit determination system implementation of the DSST, without GTDS's overhead. However, this goal has not been achieved. The 1984 DSST Standalone included complete models for the mean element motion but trunca...

Verification of the java Orekit implementation of the Draper Semi-analytical Satellite Theory (DSST) is discussed. The Orekit library for space flight dynamics has been published under the open-source Apache license V2. The DSST is unique among analytical and semi-analytical satellite theories due to the scope of the included force models. However,...

An initiative within the realm of Space Surveillance Awareness (SSA) is to create an open source software suite that can provide all space actors access to the basic SSA analysis tools needed to operate safely and efficiently in space. These applications include observation compression, orbit propagators, state transition matrix, weighted least squ...

The technology of map projections is used to provide a new, reduced-distortion color visualization of the coverage characteristics of a multiple-satellite constellation vs. user earth-fixed latitude and longitude. While global visualization plots are exhibited in this paper, the method can also be "zoomed" to provide regional plots, such as only ov...

The development of electric propulsion technology for spacecraft has led to reduced costs and longer lifespans for certain types of satellites. Because these satellites frequently undergo continuous thrust, predicting their motion and performing orbit determination on them has introduced complications for space surveillance networks. One way to imp...

This study used Optimal Control Theory to model the perturbations caused by continuous thrust. Fuel-optimal trajectories were calculated using numerical optimization techniques. Software was developed to calculate the optimal trajectories and associated thrust plans. A new force model was implemented in GTDS to accept externally generated thrust pl...

Satellite maneuver detection is an important component of Space Situational Awareness. This report summarizes work done in an effort to develop a near-real time automated maneuver detection algorithm. Discussion and results for intermediate algorithms leading up to a chosen hybrid maneuver detection algorithm are included. Results for the hybrid al...

This study is intended to improve orbit determination accuracy for 3-axis stabilized geosynchronous satellites via an improved radiative force model. The macro-model approach, developed earlier at NASA GSFC for the TDRSS spacecraft, has been adapted for the UNIX version of the Goddard Trajectory Determination System (GTDS) at the MIT Lincoln Labora...

This paper begins an effort to compare the accuracy and timing characteristics of the Draper Semianalytical Satellite Theory (DSST) developed in the USA and the Universal Semianalytical Method (USM) developed in Russia. The DSST and the USM share several characteristics: Both employ the Generalized Method of Averaging (GMA) Perturbation Theory Both...

An improved accuracy model for the J2 zonal harmonic second order terms, J 2 2 , in a general semi-analytical satellite theory is described. The new model is implemented as an option in the Draper Semi-analytic Satellite Theory (DSST) orbit propagator; the DSST is one of the several orbit propagators included in the Linux version of the R&D Goddard...

## Citations

... It is an interesting tool for a fast and accurate orbit propagation, close to current needs. Its development started in the mid-1970s at the Computer Sciences Corporation of Maryland by a team led by Paul J. Cefola [5]. ...

... Yurasov and Nazarenko also developed a semi-analytical method comparable to the DSST: the Universal Semi-analytical Method (USM). 13,14,15 However, we won't discuss it in the paper. ...

... Detection of GEO satellites is complicated both by maneuvers and noise in optical and radar observation data. The ability to differentiate between maneuvers and observational outliers has been the impetus for the development of many algorithms, including those found in a 2007 maneuver detection paper written by Folcik et al. [1]. Up until now, commonly-accepted algorithms have been based on statistical methods where the model is predetermined and then applied to real-time data. ...

... Due to the increasing complexity of space systems, and thus of the related engineering problems (Falcone, Garro, and Tundis 2014;Fortino et al. 2007;, there is a consistent investment in the development of new methods, tools and software libraries able to provide a robust and flexible way for defining, building and simulating them Fortino et al. 2006;Ido 2012;Rogovchenko-Buffoni et al. 2014;San-Juan et al. 2011). ...

... During its development, Orekit DSST has been conscientiously validated against the original FORTRAN version. 22,23,24 The current version of Orekit DSST provides a lot of features which are summarized in Table 1. Partial derivatives computed for both mean elements and shortperiodic terms using automatic differentiation ...

... where c i¼1...6 : ½ a; h; k; p; q k ðmean equinoctial elementsÞ R : averaged disturbing potential for the conservative forces n : mean mean-motion A model for the J 2 -squared AOG terms for highly eccentric cases was developed by Folcik and Cefola (2012). This model employs numerical quadrature. ...

... The current study focuses on the extension of Orekit DSST orbit determination capabilities by adding a recursive filter theory, the Extended Semi-analytical Kalman Filter (ESKF). 13,14,15 The classical (i.e., based on numerical propagation) Extended Kalman Filter (EKF) algorithm is already available in the library. However, the re-initialization of the EKF underlying orbit propagator at each measurement epoch is a major constraint for semi-analytical satellite theory. ...