scholarly journals Reentry response of the light weight radioisotope heater unit resulting from a Venus-Earth-Earth Gravity Assist maneuver accident

1988 ◽  
Author(s):  
J.C. Hagan
Keyword(s):  
Light Weight ◽  
Gravity Assist ◽  
Earth Gravity ◽  
Gravity Assist Maneuver

Set-oriented design of interplanetary low-thrust trajectories using Earth Gravity Assist

2019 ◽  
Vol 156 ◽  
pp. 208-218 ◽  
Author(s):  
Daisuke Tamakoshi ◽  
Hirohisa Kojima
Keyword(s):  
Low Thrust ◽  
Gravity Assist ◽  
Earth Gravity

scholarly journals Inter-Calibration of the OSIRIS-REx NavCams with Earth-Viewing Imagers

2019 ◽  
Vol 11 (22) ◽  
pp. 2717 ◽  
Author(s):  
David Doelling ◽  
Konstantin Khlopenkov ◽  
Conor Haney ◽  
Rajendra Bhatt ◽  
Brent Bos ◽  
...  
Keyword(s):  
Spectral Band ◽  
Field Of View ◽  
Space Probe ◽  
Gravity Assist ◽  
Tropical Ocean ◽  
Sensor Performance ◽  
Earth Gravity ◽  
The Earth ◽  
Current Constellation ◽  
Navigation Errors

The Earth-viewed images acquired by the space probe OSIRIS-REx during its Earth gravity assist flyby maneuver on 22 September 2017 provided an opportunity to radiometrically calibrate the onboard NavCam imagers. Spatially-, temporally-, and angularly-matched radiances from the Earth viewing GOES-15 and DSCOVR-EPIC imagers were used as references for deriving the calibration gain of the NavCam sensors. An optimized all-sky tropical ocean ray-matching (ATO-RM) calibration approach that accounts for the spectral band differences, navigation errors, and angular geometry differences between NavCam and the reference imagers is formulated in this paper. Prior to ray-matching, the GOES-15 and EPIC pixel level radiances were mapped into the NavCam field of view. The NavCam 1 ATO-RM gain is found to be 9.874 × 10−2 Wm−2sr−1µm−1DN−1 with an uncertainty of 3.7%. The ATO-RM approach predicted an offset of 164, which is close to the true space DN of 170. The pre-launch NavCam 1 and 2 gains were compared with the ATO-RM gain and were found to be within 2.1% and 2.8%, respectively, suggesting that sensor performance is stable in space. The ATO-RM calibration was found to be consistent within 3.9% over a factor of ±2 NavCam 2 exposure times. This approach can easily be adapted to inter-calibrate other space probe cameras given the current constellation of geostationary imagers.

Optimization of low-thrust trajectory for a mission to the asteroid 433 Eros with Earth gravity assist

2018 ◽  
Vol 97 (3) ◽  
pp. 163-174
Author(s):  
N. Marmo
Keyword(s):  
Low Thrust ◽  
Gravity Assist ◽  
Earth Gravity

On the feasibility of developing a single-stage acceleration/deceleration unit based on the oxygen-hydrocarbon engine 11D58M for a super-heavy launch vehicle

2021 ◽  
pp. 62-75
Author(s):  
Boris A. SOKOLOV ◽  
Nikolay N. TUPITSYN ◽  
Evgeniy N. TUMANIN ◽  
Igor A. KRYUKOV ◽  
Andrey V. KISELEV ◽  
...  
Keyword(s):  
Rocket Engine ◽  
Launch Vehicle ◽  
Single Stage ◽  
Rocket Engines ◽  
Liquid Propellant ◽  
Gravity Assist ◽  
Upper Stage ◽  
Gravity Assist Maneuver ◽  
Lunar Gravity Assist ◽  
Propellant Rocket

The paper presents results of unsolicited exploratory design studies done by the authors into the feasibility of developing for a super-heavy launch vehicle a single-stage oxygen-hydrocarbon acceleration/deceleration unit (ADU) with two liquid-propellant rocket engines 11D58M developed by RSC Energia, intended for insertion of manned spacecraft into lunar orbit, as well as for insertion of super-heavy spacecraft into geostationary orbit (including the orbital module high-apogee transfer profile using lunar gravity assist maneuver). It demonstrates that the single-stage ADU will have a number of important advantages over both a single-stage oxygen-hydrogen ADU and a functionally similar two-stage acceleration/deceleration system of an orbital module in the form of a tandem stack of an oxygen-hydrogen acceleration stage and correction and braking stage. To assure the start-ups of the main liquid propulsion system of the ADU, it proposes a new method for inertial propellant component phase separation in the tanks in zero-gravity environment using a pre-startup pre-programmed ullage separation turn maneuver of the orbital unit about its transverse axis of inertia. Key words: Integrated launch vehicle, launch vehicle, orbital module, upper stage, orbital transfer vehicle, acceleration/deceleration unit, ullage maneuver, liquid-propellant rocket engine.

Gravity-assist maneuvers in implementation of Martian manned expedition with an electric rocket propulsion

2019 ◽  
Author(s):  
A.A. Sinitsin
Keyword(s):  
Flight Trajectory ◽  
Gravity Assist ◽  
Ballistic Performance ◽  
Rocket Propulsion ◽  
Two Body Problem ◽  
The Earth ◽  
Methodical Approach ◽  
Gravity Assist Maneuver ◽  
The Pontryagin Maximum Principle ◽  
Made In

The paper focuses on the analysis of energy-ballistic efficiency of gravity-assist maneuvers in the implementation of the Martian manned expedition in the period 2049–2050. The purpose of this analysis was to identify the opportunities for improving the energy-ballistic performance indicators of the Martian manned expedition through gravity-assist maneuvers around the Earth and Venus. The methodical approach to calculating the main energy-ballistic indicators of the Martian manned expedition is based on dividing the flight trajectory into sections. To determine the main characteristics of these sections, the statement corresponding to the restricted two-body problem was used. The heliocentric trajectory sections were optimized using the Pontryagin maximum principle. The families of solutions with a gravity-assist maneuver near Venus were obtained, differing in the direction of the flyby of Venus and the height of the flight orbit pericenter. The research shows the existence of extremals close in characteristics, which are with the fly-by orbit pericenter altitude restriction and without it. A comparison was made in terms of the duration of the expedition and the initial mass with solutions without a gravity-assist maneuver.

On the possibility of the guidance of small asteroids to dangerous celestial bodies using the gravity-assist maneuver

2013 ◽  
Vol 47 (4) ◽  
pp. 325-333 ◽  
Author(s):  
N. A. Eismont ◽  
M. N. Boyarskii ◽  
A. A. Ledkov ◽  
R. R. Nazirov ◽  
D. W. Dunham ◽  
...  
Keyword(s):  
Gravity Assist ◽  
Gravity Assist Maneuver ◽  
Celestial Bodies

Chaotic Dynamics in a Low-Energy Transfer Strategy to the Equilateral Equilibrium Points in the Earth–Moon System

2015 ◽  
Vol 25 (05) ◽  
pp. 1550077 ◽  
Author(s):  
F. J. T. Salazar ◽  
E. E. N. Macau ◽  
O. C. Winter
Keyword(s):  
Equilibrium Points ◽  
Low Energy ◽  
The Moon ◽  
Gravity Assist ◽  
Moon System ◽  
Keplerian Orbits ◽  
The Earth ◽  
Chaotic Region ◽  
Gravity Assist Maneuver ◽  
Three Body

In the frame of the equilateral equilibrium points exploration, numerous future space missions will require maximization of payload mass, simultaneously achieving reasonable transfer times. To fulfill this request, low-energy non-Keplerian orbits could be used to reach L4 and L5 in the Earth–Moon system instead of high energetic transfers. Previous studies have shown that chaos in physical systems like the restricted three-body Earth–Moon-particle problem can be used to direct a chaotic trajectory to a target that has been previously considered. In this work, we propose to transfer a spacecraft from a circular Earth Orbit in the chaotic region to the equilateral equilibrium points L4 and L5 in the Earth–Moon system, exploiting the chaotic region that connects the Earth with the Moon and changing the trajectory of the spacecraft (relative to the Earth) by using a gravity assist maneuver with the Moon. Choosing a sequence of small perturbations, the time of flight is reduced and the spacecraft is guided to a proper trajectory so that it uses the Moon's gravitational force to finally arrive at a desired target. In this study, the desired target will be an orbit about the Lagrangian equilibrium points L4 or L5. This strategy is not only more efficient with respect to thrust requirement, but also its time transfer is comparable to other known transfer techniques based on time optimization.

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