MUSE (spacecraft)

Mission to Uranus for Science and Exploration (MUSE)

Mission type	Reconnaissance, atmospheric probe
Operator	European Space Agency
Spacecraft properties
Spacecraft	MUSE
Launch mass	4,219 kg (9,301 lb)
Dry mass	2,073 kg (4,570 lb)
Payload mass	Orbiter: 252 kg (556 lb) Probe: 150 kg (330 lb)
Dimensions	cylindrical bus 3 m × 1.6 m
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) is a European proposal for a dedicated mission to the planet Uranus to study its atmosphere, interior, moons, rings, and magnetosphere. 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.

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. The mission addresses the themes of the ESA Cosmic Vision 2015-2025.

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.

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.

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. The propulsion system for the Earth-Uranus transfer would be chemical: Monomethylhydrazine and Mixed Oxides of Nitrogen (MMH/MON) propellant combination is used.

Atmospheric probe

See also: Atmosphere of Uranus

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. 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.

Proposed instruments

Instrument	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

• The total mass budget for scientific instruments is 150 kg (330 lb); if all of proposed instruments are selected, they would sum a total payload mass of 108.4 kg (239 lb)
• Green background denotes entry probe instruments.

See also

• Atmosphere of Uranus
• Exploration of Uranus
• Moons of Uranus