Earth-based navigational capabilities for planetary missions.
Baseline navigation system for planetary missions using two way Doppler
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Baseline navigation system for planetary missions using two way Doppler
This paper presents the findings of planetary mission studies which supported development of the Space Science Strategic Plan.
Results presented are intended to assist planners and the mission analysis community in assessing the performance impact (pro or con) of launching planetary missions from an orbiting space station as compared to the usual, ground-based Shuttle launch of such missions. The analyses comprising this assessment include: (1) a basic understanding and description of the space station launch problem; (2) examination of alternative injection strategies and selection of the most appropriate strategy for minimizing performance penalties; and (3) quantitative comparison of station-launched and Shuttle-launched performance over a wide energy/mass range of planetary mission opportunities. Data for each mission covers a full 360 deg of possible nodal location of the space station orbit. The main results are that planetary missions can be launched from a space station within acceptable penalty bounds, and that the station serving as a staging base/propellant depot can benefit some missions requiring large payload mass or high injection energy.
An overview of the missions operations systems (MOS) used to support NASA planetary missions is given. The principal factors governing the design characteristics of MOS are discussed, including: the communications requirements of spacecraft over long distance from the earth, the fragility of the scientific payloads, and the inability to carry out planetary missions more than a few times a decade. The uplink and downlink parts of the MOS of Galileo and Voyager spacecraft are illustrated as examples of successful MOS design. A black and white photograph of the operations control center of JPL is provided.
Several interesting planetary missions are either enabled or significantly enhanced by nuclear electric propulsion (NEP) in the 50 to 100kW power range.
Space radiation hazards for manned planetary missions in terms of Van Allen and solar flare proton radiation
Experimental program planning for manned planetary missions using Mars landing mission for illustration
The paper deals with the concept of a small planetary mission that might be described as one which: (1) focuses on a narrow set of discovery-oriented objectives, (2) utilizes largely existing and proven subsystem capabilities, (3) does not tax future launch vehicle capabilities, and (4) is flexible in terms of mission timing such that it can be easily integrated with launch vehicle schedules. Three small planetary mission concepts are presented: a tour of earth-sun Lagrange regions in search of asteroids which might be gravitationally trapped, a network of spacecraft to search beyond Pluto for a tenth planet; and a probe which could be targeted for infrequent long period 'comets of opportunity' or for a multitude of shorter period comets.
Space station requirements for lunar and planetary missions are discussed. Specific reference is made to projected Ceres and Kopff missions; Titan probes; Saturn and Mercury orbiters; and a Mars sample return mission. Such requirements as base design; station function; program definition; mission scenarios; uncertainties impact; launch manifest and mission schedule; and shuttle loads are considered. It is concluded that: (1) the impact of the planetary missions on the space station is not large when compared to the lunar base; (2) a quarantine module may be desirable for sample returns; (3) the Ceres and Kopff missions require the ability to stack and checkout two-stage OTVs; and (4) two to seven manweeks of on-orbit work are required of the station crew to launch a mission and, with the exception of the quarantine module, dedicated crew will not be required.
Trajectory design and computer programs for planetary mission analysis
Observation requirements for unmanned planetary missions
Solar electric propulsion /SEP/ for automated planetary missions, discussing system characteristics, capabilities and costs
Solar electric propulsion /SEP/ for automated planetary missions, discussing system characteristics, capabilities and costs
Some of the planetary missions using microspacecraft of mass on the order of 10 kg which are presently being considered at JPL are discussed. The primary benefits offered by this type of spacecraft is the small and relatively inexpensive launch vehicles and short program development schedules. A mission presently considered by the Asteroid Investigation with Microspacecraft (AIM) study is described with special attention given to the spacecraft configuration; the AIM mission will launch three spacecraft from a single Pegasus vehicle, achieving separate flybys for three near-earth asteroids. Attention is also given to the salient features of the Mars Rover Sample Return mission, the Venus Atmospheric Sounder, and the Comet Nucleus Mission, for which the application of microspacecraft technology is considered.
Target: Europa lander mission, plus future NASA outer planetary missions in radiation environments
The NASA Discovery Program of small planetary missions will provide opportunities to continue scientific exploration of the solar system in today's cost-constrained environment. Using a multidisciplinary team, JPL has developed plans to provide mission operations within the financial parameters established by the Discovery Program. This paper describes experiences and methods that show promise of allowing the Discovery Missions to operate within the program cost constraints while maintaining low mission risk, high data quality, and reponsive operations.
There is currently a vigorous investigation underway of low-cost planetary missions using small, inexpensive spacecraft. In order to keep the total mission costs down either a medium class launch vehicle such as a Delta II or an intermediate class launch vehicle such as an Atlas IIA or Atlas IIAS would be required for these planetary missions.
This paper summarizes a portion of the planetary mission analysis results of past and present studies conducted by Rockwell International for NASA-MSFC (Contract NAS8-27360) dealing with the feasibility of a Solar Electric Propulsion Stage (SEPS). The SEPS is envisioned as an upper stage of a transportation system capable of delivering either separable payload spacecraft or attached science packages to various planetary targets. The purpose of the paper is to demonstrate that, from a payload performance capability standpoint, a common SEP Stage can deliver various payloads to a host of planetary targets including inner and outer planets, asteroids, and comets.