MUSE (spacecraft)

Mission to Uranus for Science and Exploration (MUSE)
Mission type Reconnaissance, atmospheric probe
Operator European Space Agency[1]
Spacecraft properties
Spacecraft MUSE
Launch mass 4,219 kg (9,301 lb)[2]
Dry mass 2,073 kg (4,570 lb)
Payload mass Orbiter: 252 kg (556 lb)
Probe: 150 kg (330 lb)[3]
Dimensions cylindrical bus 3 m × 1.6 m[3]
Power 436 W
Li-ion batteries: 3,376 Wh
Generator: four ASRGs
Start of mission
Launch date September 2026 (proposed)
November 2029 (if delayed)
Rocket Ariane 5 (proposed)
Uranus orbiter
Orbital insertion 2044 (proposed)
2049 (if delayed)
Orbits 36
Uranus atmospheric probe
Spacecraft component Entry probe
Atmospheric entry 2044 (proposed)

MUSE (Mission to Uranus for Science and Exploration[3]) is a European proposal for a dedicated mission to the planet Uranus to study its atmosphere, interior, moons, rings, and magnetosphere.[2][4] It is proposed to be launched with an Ariane 5 in 2026, travel for 16.5 years to reach Uranus in 2044, and would operate until 2050.[4]

The European Space Operations Centre would monitor and control the mission, as well as generate and provide the raw data sets. In 2012, the cost was estimated at €1.8 billion.[2] The mission addresses the themes of the ESA Cosmic Vision 2015-2025.[2] This was designed as an L-Class flagship level mission.[5] However, it is constrained by the need for RTGs.[5] MUSE was also analyzed in the USA as an Enhanced New Frontiers class mission in 2014.[6]

Orbiter

Uranus and its six largest moons compared at their proper relative sizes and relative positions. From left to right: Puck, Miranda, Ariel, Umbriel, Titania, and Oberon

The orbiter science phase would consist on the Uranus Science Orbit (USO) phase of approximately 2 years in a highly elliptic polar orbit to provide best gravimetry data, during which 36 Uranus orbits are performed.[4]

Subsequently, the orbiter will continue to the Moon Tour (MT) phase, which would last three years. During this phase, the periapsis would be raised, facilitating nine flybys of each of Uranus' five major moons: Miranda, Ariel, Umbriel, Titania, and Oberon.[2][4]

Because of the long distance from the Sun (20 AU on average), the orbiter would not be able to use solar panels, requiring instead four Advanced Stirling Radioisotope Generators (ASRGs) to be developed by ESA.[2][4] The propulsion system for the Earth-Uranus transfer would be chemical: Monomethylhydrazine and Mixed Oxides of Nitrogen (MMH/MON) propellant combination is used.[4]

Atmospheric probe

Understanding why Uranus emits such a small amount of heat can only be done in the context of thermodynamic modeling of the atmosphere (density, pressure, and temperature). Therefore, the atmosphere needs to be characterized from both a composition and a thermodynamic point of view.[2] The chemical information to retrieve is the elemental concentrations, especially of disequilibrium species, isotopic ratios and noble gases, in combination with information regarding the distribution of aerosol particles with depth.

Twenty days before entry, the atmospheric probe would separate from the spacecraft and enter the outer atmosphere of Uranus at an altitude of 700 km at 21.8 km/s. It would descend by free fall and perform atmospheric measurements for about 90 minutes down to a maximum of 100 bars (1,500 psi) pressure.[2][4]

Proposed instruments

Instrument[2][4] Heritage Description Range
VINIRS Dawn VIR Visible and Near Infrared Spectrometer λ: 0.25 - 5 μm
96 bands (1.8 nm per band)
IRS Cassini CIRS Thermal Infrared Spectrometer λ: 7.16 - 16.67 μm
1 × 10 array of 0.273 mrad squares
UVIS Cassini UVIS Ultraviolet Imaging Spectrograph λ: 55.8 - 190 nm
RPW Cassini RPWS Radio and Plasma Wave Instrument 1 Hz - 16 MHz (various channels)
MAG Juno MAG
Swarm VFM		 Fluxgate Magnetometer Dual 3 axis, <1 nT accuracy range of 0 - 20000 nT
TELFA C/NOFS
VEFI antennas		 TLF band and ELF Antenna Schumann resonances
ICI Rosetta ICA Ion Composition Instrument Positive ions from 25 eV to 40 keV (dE/E = 0.07)
EIS Rosetta IES Electron and Ion Sensor Electrons and ions from 1 eV/e to 22 keV/e (dE/E = 0.04)
EPD New Horizons
PEPSSI		 Energetic Particle Detector Protons: 15 keV - 3MeV
Alphas: 25 keV - 3 MeV
CNO: 60 keV - 30 MeV
Electrons: 15 keV - 1MeV
NAC Cassini ISS Narrow Angle Camera Res: 6 μrad/pixel
Spectral range: 350 - 1050 nm
WAC Cassini ISS Wide Angle Camera Res: 60 μrad/pixel
Spectral range: 350 - 1050 nm
RSE Cassini ISS Radio Science Experiment Allan deviation at T= 100 s of 1 × 10−13
Transponders operating at S, X and Ka band.
MWR Juno MWR Microwave Radiometer 0.6 – 22 GHz
Gain up to 80 dB
Temperature profile up to 200 bar
DC Cassini CDA
New Horizons SDC		 Dust Analyzer Particle mass range: 10−15 to 10−9 kg
Particle size range (radius): 1 - 10 μm
DWE Huygens DWE Doppler Wind Experiment dv = 1 m/s
Depth: 20 bar
AP3 Huygens HASI Atmospheric Physical Properties Package Temperature, pressure and density profiles
Depth: 0 - 20 bar
GCMS Huygens GCMS Gas Chromatograph and Mass Spectrometer Heavy elements, noble gases, key isotopic ratios (H2/He, D/H, PH3, CO) and Disequilibrium Species
AS & NEP Huygens ACP
Galileo GPNE		 Aerosol Sampling System and Nephelometer Particle size range (radius): 0.2 to 20 μm,
at concentrations of < 1 m³

MUSE as new New Frontiers mission

In 2014 a paper was released considering MUSE under the constraints of an enhanced New Frontiers mission.[6] This included a cost cap of 1.5 billion USD, and one of the big differences was the use of an Atlas V 551 rocket.[6]

See also

References

  1. ↑ Kane, Van (25 September 2013). "Europe Will Select Its Next Major Science Mission in November". The Planetary Society. Retrieved 2016-03-31.
  2. 1 2 3 4 5 6 7 8 9 Costa, M.; Bocanegra, T.; Bracken, C.; et al. (June 2012). Mission to the Uranus System: MUSE. Unveiling the evolution and formation of icy giants (PDF). 2012 Post Alpbach Summer School. Madrid, Spain.
  3. 1 2 3 Saikia, S. J.; Daubar, I. J.; et al. (2014). Na new frontiers mission concept for the exploration of Uranus (PDF). 45th Lunar and Planetary Science Conference.
  4. 1 2 3 4 5 6 7 8 Bocanegra-Bahamón, Tatiana (2015). "MUSE Mission to the Uranian System: Unveiling the evolution and formation of ice giants" (PDF). Advances in Space Research. doi:10.1016/j.asr.2015.01.037.
  5. 1 2
  6. 1 2 3
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