Engineering topics

Beerer, Joseph G.

Publications and source records attributed to Beerer, Joseph G..

6 records

NASA NTRS2012

Designing Mission Operations for the Gravity Recovery and Interior Laboratory Mission

The Gravity Recovery and Interior Laboratory (GRAIL) mission has placed two orbiters in a low altitude polar orbit around the moon to study its internal structure. GRAIL mission to the Moon offered unique challenges to operatiotn: (1) operate twin-orbiters in parallel, (2) numerous maneuvers, (3) short, compact mission with six unique phases, and (4) detailed contingency planning required.

Orbital Period Reduction (OPR)↗

NASA NTRS2012

Operating the Dual-Orbtier GRAIL Mission to Measure the Moon's Gravity

The GRAIL mission is on track to satisfy all prime mission requirements. The performance of the orbiters and payload has been exceptional. Detailed pre-launch operations planning and validation have paid off. Prime mission timeline has been conducted almost exactly as laid out in the mission plan. Flight experience in the prime mission puts the flight team in a good position for completing the challenges of the extended mission where the science payoff is even greater

Moon's interior structure↗

NASA NTRS2012

Operating the Dual-Orbiter GRAIL Mission to Measure the Moon's Gravity

NASA's mission to measure the Moon's gravity and determine the interior structure, from crust to core, has almost completed its 3-month science data collection phase. The twin orbiters of the Gravity Recovery and Interior Laboratory (GRAIL) mission were launched from Florida on September 10, 2011, on a Delta-II launch vehicle. After traveling for nearly four months on a low energy trajectory to the Moon, they were inserted into lunar orbit on New Year's Eve and New Year's Day. In January 2012 a series of circularization maneuvers brought the orbiters into co-planar near-circular polar orbits. In February a distant (75- km) rendezvous was achieved and the science instruments were turned on. A dual- frequency (Ka and S-band) inter-orbiter radio link provides a precise orbiter-to-orbiter range measurement that enables the gravity field estimation. NASA's Jet Propulsion Laboratory in Pasadena, CA, manages the GRAIL project. Mission management, mission planning and sequencing, and navigation are conducted at JPL. Lockheed Martin, the flight system manufacturer, operates the orbiters from their control center in Denver, Colorado. The orbiters together have performed 28 propulsive maneuvers to reach and maintain the science phase configuration. Execution of these maneuvers, as well as the payload checkout and calibration activities, has gone smoothly due to extensive pre-launch operations planning and testing. The key to the operations success has been detailed timelines for product interchange between the operations teams and proven procedures from previous JPL/LM planetary missions. Once in science phase, GRAIL benefitted from the payload operational heritage of the GRACE mission that measures the Earth's gravity.

Moon missions↗

NASA NTRS2012

Designing Mission Operations for the Gravity Recovery and Interior Laboratory Mission

NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, to understand the internal structure and thermal evolution of the Moon, offered unique challenges to mission operations. From launch through end of mission, the twin GRAIL orbiters had to be operated in parallel. The journey to the Moon and into the low science orbit involved numerous maneuvers, planned on tight timelines, to ultimately place the orbiters into the required formation-flying configuration necessary. The baseline GRAIL mission is short, only 9 months in duration, but progressed quickly through seven very unique mission phases. Compressed into this short mission timeline, operations activities and maneuvers for both orbiters had to be planned and coordinated carefully. To prepare for these challenges, development of the GRAIL Mission Operations System began in 2008. Based on high heritage multi-mission operations developed by NASA's Jet Propulsion Laboratory and Lockheed Martin, the GRAIL mission operations system was adapted to meet the unique challenges posed by the GRAIL mission design. This paper describes GRAIL's system engineering development process for defining GRAIL's operations scenarios and generating requirements, tracing the evolution from operations concept through final design, implementation, and validation.

MOS↗

NASA NTRS1991

Mars Observer trajectory and orbit design

The Mars Observer launch, interplanetary, Mars orbit insertion, and mapping orbit designs are described. The design objective is to enable a near-maximum spacecraft mass to be placed in orbit about Mars. This is accomplished by keeping spacecraft propellant requirements to a minimum, selecting a minimum acceptable launch period, equalizing the spacecraft velocity change requirement at the beginning and end of the launch period, and constraining the orbit insertion maneuvers to be coplanar. The mapping orbit design objective is to provide the opportunity for global observation of the planet by the science instruments while facilitating the spacecraft design. This is realized with a sun-synchronous near-polar orbit whose ground-track pattern covers the planet at progressively finer resolution.

Beerer, Joseph G.↗

NASA NTRS1989

Mars Observer mission design

The spacecraft for the Mars Observer mission is described, and an interplanetary trajectory design maximizing the spacecraft dry mass delivered into its mapping orbit is presented, along with an orbit insertion strategy minimizing spacecraft propulsive requirements. Emphasis is placed on the mapping orbit designed to meet the science requirements for a low-altitude near-circular near-polar orbit which is sun-synchronous with the dayside equatorial crossing at 2 PM local mean solar time. Additional requirements on the design are that the mapping orbit have a repeating groundtrack of no more than 7 sols and comply with the NASA Planetary Protection requirements. It is planned to operate the spacecraft and instruments in a repetitive fashion to minimize mission operation complexity and cost.

Beerer, Joseph G.↗