 Artist's impression of the Enceladus Orbilander | |
| Mission type | Enceladus Orbiter and Lander |
|---|---|
| Operator | NASA |
| Website | https://space.jhuapl.edu/projects-and-studies/enceladus-orbilander |
| Mission duration |
|
| Spacecraft properties | |
| Manufacturer | APL (proposed) |
| Launch mass | 6610 kg[1]: 18 |
| Dry mass | 2690 kg |
| Power | 741 W (at launch) 589 W (landing) |
| Start of mission | |
| Launch date | October 2038 (proposed)[1]: 33 |
| Rocket | Space Launch System Block 2 (proposed) |
| Launch site | Kennedy Space Center,Pad 39B |
| Contractor | NASA |
| Flyby ofJupiter | |
| Closest approach | October 2040 (proposed) |
| Distance | 4,730,000 km (2,940,000 mi) |
| Saturn orbiter | |
| Orbital insertion | August 2045 (proposed) |
| Orbital departure | early 2050 (proposed) |
| Enceladus orbiter | |
| Orbital insertion | early 2050 (proposed) |
| Orbital departure | mid 2051 (proposed) |
| Enceladus lander | |
| Landing date | mid 2051 (proposed) |
Large Strategic Science Missions Planetary Science Division | |
TheEnceladus Orbilander is a proposedNASAFlagship mission toSaturn's moonEnceladus. The Enceladus Orbilander would spend a year and a half orbiting Enceladus and sampling itswater plumes, which stretch into space, before landing on the surface for a two-year mission to study materials for evidence of life.[1] The mission, with an estimated cost of $4.9 billion, could launch in the late 2030s on aSpace Launch System orFalcon Heavy with a landing in the early 2050s. It was proposed in the2023–2032 Planetary Science Decadal Survey as the second highest priority Flagship mission, after theUranus Orbiter and Probe.[2][3]
At 500 kilometres (310 miles) in diameter, Enceladus is the sixth largest moon of Saturn and the 19th largest in theSolar System.[4] Enceladus has been visited and imaged in detail by three other probes: the twinVoyager spacecraft, and the Saturn orbitingCassini spacecraft. Out of these,Cassini investigated Enceladus in the most detail and contributed the most to the current scientific understanding of Enceladus. Cassini's 23 targeted close flybys[5] helped discover that Enceladus is a geologically active world, with young (recently formed/solidified) terrain. The flybys also showed active, warm water plumes, along with evidence hinting at a subsurface ocean.[6] Cassini also provided evidence of hydrothermal processes driving both the geysers and Enceladus's active geology, making the moon one of the most attractiveplaces to find life within the solar system.
After Cassini's mission, a variety of proposals to follow-up on Cassini's findings at Enceladus.[7]Journey to Enceladus and Titan, anastrobiology mission to Enceladus and Titan, competed for the 13thDiscovery Program mission but was not selected.[8][9] Later, In 2017, two Enceladus focused astrobiology missions,Enceladus Life Signatures and Habitability andEnceladus Life Finder competed for the 4thNew Frontiers mission, but were ultimately not selected.[10][11]
The Enceladus Orbilander proposal was created by a team led by Shannon MacKenzie to support thePlanetary Science Decadal Survey.[12] While previous mission studies had investigated multiple flybys to study Enceladus, MacKenzie's team, studying aFlagship mission architecture with a greater budget cap, decided to study an orbiter, lander, or a combination thereof.[13] Ultimately, the decision to combine the orbiter and lander into one spacecraft was informed by Enceladus's small size and negligible gravity, which results in trivial delta-v to land.[14]
In the2022-2032 Planetary Decadal Survey, the Enceladus Orbilander was recommended as the second highest priority new flagship mission.[15] The selection was motivated by proposal'sexobiology andplanetary habitability focus.[16]
Due to Enceladus's small size, the amount of energy required to land compared to capturing into orbit is negligible. Therefore, the Enceladus Orbilander is envisioned uniquely combine both the functions of an orbiter and a lander into a single spacecraft.[17]
The proposed spacecraft will carry three separate instrument suites and a sampling system. Each instrument suite is tailored towards a different regime of science operations.
The proposed instruments are:[1]: 10, B7-B10
| Instrument | Heritage Instrument (Mission) | Science Suite |
|---|---|---|
| High-Resolution Mass Spectrometer (HRMS) | MASPEX (Europa Clipper) | Life Detection Suite |
| Separation Mass Spectrometer (SMS) | Sample Analysis at Mars (Curiosity) | |
| Electrochemical Sensor Array (ESA) | Wet Chemistry Laboratory (Phoenix) | |
| Microcapillary Electrophoresis-Laser Induced Fluorescence | N/A | |
| Microscope | MECA Atomic Force Microscope (Phoenix) | |
| Solid State Nanopore Sequencer | N/A | |
| Narrow Angle Camera (NAC) | Long Range Reconnaissance Imager (New Horizons) | Remote Sensing and Reconnaissance Suite |
| Wide Angle Camera (WAC) | ECAM-M50 (Janus) | |
| Thermal Emission Spectrometer (TES) | Mercury Radiometer and Thermal Infrared Spectrometer (BepiColombo) | |
| Context Imager | Stereo Surface Imager (Phoenix) | In Situ Suite |
| Seismometer | Seismic Experiment for Interior Structure (Insight) |
Additionally, three separate sampling systems are proposed for each stage of flight: a 1 square meter funnel to passively collect particles, a scoop for active particle collection on the surface, and a gas inlet for gas emissions.[1]: 10, B11
The Enceladus Orbilander is proposed to be launched in October 2038.[1]: 4 The spacecraft is proposed to be launched by aSpace Launch System Block II variant with aCastor 30B upper stage, although aFalcon Heavy has also been considered but would require the spacecraft to launch on a slower trajectory with flybys of Venus.[1]: 7 The spacecraft's proposed launch is timed so that a Jupitergravity assist can be performed in October 2040 to save propellant for Saturn orbital insertion in August 2045.[1]: 19 In Saturn orbit, the spacecraft will embark on a complex, 4.5 year long tour of themoons of Saturn, using gravity assists off moons such asTitan,Rhea,Dione, andTethys to lower theorbital inclination of the spacecraft.[1]: 21-22 After a series of flybys with Enceladus itself, the spacecraft will enter Enceladus orbit.
The spacecraft will spend 1.5 years in a 12 hours longelliptical orbit around Enceladus.[1]: 20 The closest point of the orbit to the surface will pass over the south polartiger stripes to collect plume particles and remote sensing data. Whilst orbiting Enceladus, mission planners will use high resolution images and other data to determine a safelanding ellipse.[14] When mission planners decide to land the spacecraft, the Enceladus Orbilander will lower its orbit and begin a powered descent towards the surface. The spacecraft will use terrain-relative navigation similar to systems used onOSIRIS-REx to avoid hazards during the descent.[17] When the spacecraft is 10 metres (33 ft) above the surface, the main engine shuts off to avoid contaminating the area, and the spacecraft pitches to its side before soft landing.[1]: 16
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