A CASE STUDY: AGI Software for NASA LADEE Flight Dynamics System

STK and ODTK-Based FDS used Operationally for Mission to Moon

Solution | Space Missions

Challege:

Build a flight dynamics system (FDS) for LADEE that supports trajectory design, maneuver planning, orbit determination and acquisition data and product generation.

Solution:

Space Exploration Engineering (SEE) and Applied Defense Solutions (ADS) built an FDS based on AGI’s STK, STK Astrogator and Orbit Determination Tool Kit software, which has already been proven on various operational NASA, commercial and military deep space missions.

Results:

Reusing proven software reduced development time and risk and enabled easy collaboration among NASA centers. The LADEE FDS was tailored to operational workflows and built to support multiple mission rehearsals and operations simultaneously.

NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft launched on September 7, 2013, from Wallops Flight Facility on a mission to orbit the Moon to gather detailed information about the structure and composition of the thin lunar atmosphere and determine whether dust is being lofted into the lunar sky. Its Flight Dynamics System (FDS) was built by Applied Defense Solutions (ADS) and Space Exploration Engineering (SEE), in close coordination with NASA Ames Research Center. The FDS uses AGI software for trajectory design, maneuver planning, orbit determination and acquisition data and product generation.

ADS has used AGI products to operate well more than 20 military, NASA and commercial spacecraft, including IBEX, LCROSS and the Radiation Belt Storm Probes. Because the software has been proven in so many operational NASA missions and is in use at most centers, the LADEE team was confident in using it for their FDS, and it made collaboration that much easier. Reuse also helped reduce technical risk and testing time. “We factored in all of the orbit analyst decision points in advance, so the whole system is tailored for operational workflows,” said John Carrico, senior scientist at ADS and part of the FDS team at Ames with SEE’s Mike Loucks. The user interface is available on multiple machines (up to 8 simultaneously with flexible licensing to add more as needed), and users can configure it to run “automatically” or in an interactive mode. The LADEE FDS was built so that it can support multiple mission rehearsals and operations simultaneously, making it mission-independent.

STK and STK SatPro
STK is used for all acquisition data and product generation—pointing products, constraints, eclipses, etc. It’s also used to plan all attitude maneuvers for the entire mission. STK is also used to perform attitude constraint violation checks such as ensuring that the Sun does not enter the field of view of the star trackers.

STK Astrogator
Astrogator was used to plan a series of maneuvers using a set of phasing orbits to target arrival at the Moon. It was also used to plan a series of “lunar orbit acquisition” maneuvers to get into orbit about the Moon, as well as maneuvers to lower LADEE’s orbit for science collection and to perform orbit stationkeeping. Astrogator also provided unique capabilities for initial orbit determination.

Orbit Determination Tool Kit
ODTK is being used to perform orbit determination for the entire mission, from launch and early operations to cislunar phasing loops to lunar orbit. AGI worked closely with the LADEE team to ensure that the lunar gravity field was modeled in a sufficient manner to meet requirements before launch.

Learn more: agi.com/space