Mars Microprobe entry analysis

Braun, Robert D.; Mitcheltree, Robert A.; Cheatwood, F. McNeil

doi:10.1109/aero.1997.574416

Cited by 6 publications

(4 citation statements)

References 10 publications

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“…O -nominal conditions examined are discussed in Ref. 4. To assess the e ect of these o -nominal conditions, the 3-values from Tables 4 and 5 mean value plus 3-deviation can be compared with values predicted from traditional heatshield sizing approaches.…”

Section: Angle-of-attack E Ectsmentioning

confidence: 99%

Aerothermal Heating Predictions for Mars Microprobe

Mitcheltree

DiFulvio

Horvath

et al. 1999

Journal of Spacecraft and Rockets

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A combination of computational predictions and experimental measurements of the aerothermal heating expected on the two Mars Microprobes during their entry to Mars are presented. The maximum, non-ablating, heating rate at the vehicle's stagnation point at = 0 0 is predicted for an undershoot trajectory to be 194 W=cm 2 with associated stagnation point pressure of 0.064 atm. Maximum stagnation point pressure occurs later during the undershoot trajectory and is 0.094 atm. From computations at seven overshoot-trajectory points, the maximum heat load expected at the stagnation point is near 8800 J=cm 2 . Heat rates and heat loads on the vehicle's afterbody are much lower than the forebody. At zero degree angle-of-attack, heating over much of the hemispherical afterbody is predicted to be less than 2 percent of the stagnation point v alue. Good qualitative agreement is demonstrated for forebody and afterbody heating between CFD calculations at Mars entry conditions and experimental thermographic phosphor measurements from the Langley 20-Inch Mach 6 Air Tunnel. A n o v el approach which incorporates six degree-of-freedom trajectory simulations to perform a statistical estimate of the e ect of angle-of-attack, and other o -nominal conditions, on heating is included. Nomenclature B = Ballistic coe cient, kg=m 2 C h = heat transfer coe cient M = Mach n umber P = pressure, atm q = heat rate, W=cm 2 R n = nose radius, m s = surface distance from geometric stagnation point, m t = independent v ariable time, s V = v elocity, m=s x; z = independent spatial dimensions, m = angle-of-attack, deg = side-slip angle, deg = density, kg=m 3 = standard deviation IntroductionWhen the Mars Surveyor 98 Lander is launched in January of 1999, it will transport not only its own lander to Mars, but two small soil penetrators. These Aerospace Engineer, Aerothermodynamics Branch, Aeroand Gas-Dynamics Division, NASA Langley Research Center, Senior member AIAA.y Aerospace Engineer, Aerothermodynamics Branch, Aeroand Gas-Dynamics Division, NASA Langley Research Center, Senior member AIAA.z Aerospace Engineer, Aerothermodynamics Branch, Aeroand Gas-Dynamics Division, NASA Langley Research Center, Senior member AIAA.x Aerospace Engineer, Vehicle Analysis Branch, Space Systems and Concepts Division, NASA Langley Research Center, Member AIAA.Copyright c 1998 by the American Institute of Aeronautics and Astronautics, Inc. No copyright is asserted in the United States under Title 17, U.S. Code. The U.S. Government has a r o y alty-free license to exercise all rights under the copyright claimed herein for governmental purposes. All other rights are reserved by the copyright o wner.two Mars Microprobes 1 are the second of the Deep Space missions from NASA's New Millennium Program O ce. Upon arrival at Mars, the penetrators will be released from the cruise stage and begin a free fall to the surface. This paper focuses on predicting the convective heating which the aeroshells will encounter during the hypersonic portion of that Mars entry. Knowledge of the...

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Section: Angle-of-attack E Ectsmentioning

confidence: 99%

Aerothermal Heating Predictions for Mars Microprobe

Mitcheltree

DiFulvio

Horvath

et al. 1999

Journal of Spacecraft and Rockets

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“…The forebody is a cylinder with a hemispherical nose and is 10 cm long, 39 mm in diameter, made from a steel tube and its mass is 670 g. The hemispherical nose cap, attached by a screw ®tting, is made of tungsten, in order to bring the center of mass of the forebody±aftbody assembly as far forward as possible to ensure entry stability (Braun et al, 1997). Within the steel tube is a triangular prism made from three circuit boards carrying a microcontroller and instrument electronics and inside this prism is a motor used to drive the drill for the water detection experiment.…”

Section: Flight Hardwarementioning

confidence: 99%

Penetration tests on the DS-2 Mars microprobes: penetration depth and impact accelerometry

Lorenz

Moersch

Stone

et al. 2000

Planetary and Space Science

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We describe the results of three separate sets of impact tests conducted during the development of the DS-2 Mars Microprobe mission. As well as indicating the promise of penetration to H0.5 m depth on Mars, these tests show the utility of accelerometer data in determining the penetration depth, the hardness of the surface material and the existence of layers, and the presence of coarse-grained material. Various lessons learned in instrumentation and operation, airgun testing and target characterization, and penetrator design for reliable separation, are discussed. 7

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“…7 This program has been utilized previously for similar applications. [8][9][10] The three-DOF program (which integrates the translation equations of motion) is used from spacecraft separation to atmospheric interface. The six-DOF version of POST (which integrates the translational and rotational equations of motion) is used from atmospheric interface to parachute deployment.…”

Section: Trajectory Simulationmentioning

confidence: 99%

Entry Dispersion Analysis for the Genesis Sample Return Capsule

Desai

Cheatwood

2001

Journal of Spacecraft and Rockets

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p.n.desai@larc.nasa.gov, f.m.cheatwood@larc.nasa.gov Genesis will be the first mission to return samples from beyond the Earth-Moon system. The spacecraft will be inserted into a halo orbit about the L1 (SunEarth) libration point where it will remain for two years collecting solar wind particles. Upon Earth return, the sample return capsule, which is passively controlled, will descend under parachute to Utah. The present study describes the analysis of the entry, descent, and landing scenario of the returning sample capsule. The robustness of the entry sequence is assessed through a Monte Carlo dispersion analysis where the impact of off-nominal conditions is ascertained. The dispersion results indicate that the capsule attitude excursions near peak heating and drogue chute deployment are within Genesis mission limits. Additionally, the size of the resulting 3-σ landing ellipse is 47.8 km in downrange by 15.2 km in crossrange, which is within the Utah Test and Training Range boundaries.

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Mars Microprobe entry analysis

Cited by 6 publications

References 10 publications

Aerothermal Heating Predictions for Mars Microprobe

Aerothermal Heating Predictions for Mars Microprobe

Penetration tests on the DS-2 Mars microprobes: penetration depth and impact accelerometry

Entry Dispersion Analysis for the Genesis Sample Return Capsule

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