Seven things you need to know about NASA’s new $4.9 billion mission to Saturn’s tiny moon Enceladus

NASA goes to Enceladus! Last month, the National Academy of Sciences finally released its 10-Year Survey of Planetary Science and Astrobiology – widely seen as a “to do” list for NASA – and the star of the show was the recommendation NASA to develop the Enceladus Orbilander mission to explore Saturn’s sixth satellite. bigger moon.

Enceladus has a warm, salty ocean beneath its icy surface. It also has plumes or geysers that spew this liquid into space. It means unprecedented access to an alien ocean, which is why some planetary scientists and astrobiologists rank it as the most exciting object in the solar system. However, Orbilander won’t be reaching Enceladus anytime soon.

Here are seven things you need to know about Orbilander’s jaw-dropping plans to orbit and land on Enceladus:

1. Orbilander will land and take pictures

Orbilander will orbit Enceladus, essentially sampling its plumes – as ice particles in space – twice a day for 200 days. Then it will land. Enceladus has about a hundredth the gravity of Earth, so landing should be relatively easy compared to Mars. It will then remain at the surface for at least a few years, occasionally changing position, to collect (probably much larger) samples of this plume material that has settled.

It will also have cameras on board to send back photos from orbit and from the surface, as well as a seismometer to capture possible “ice quakes”. At the end of the mission, Orbilander will remain on the surface of Enceladus.

2. It won’t happen until 2050, and that’s perfect

Orbilander’s concept suggests a launch in October 2038 (with a backup in November 2039) to arrive in 2050. That’s a long time, Orbilander not expected to be launched by NASA until 2029 at the earliest. Of course, 2050 – at least – is a very long time to wait for the first scientific results from a NASA mission.

That’s exploring the outer solar system for you.

Still, there’s a good scientific argument for waiting until then anyway. Beginning development of Orbilander in the late 2020s means arriving at Enceladus in the early 2050s when its south pole enters the austral summer. This means more of the moon will be illuminated as the mission progresses.

3. It could be launched on a SpaceX Starship spacecraft

To reach Saturn in seven years – which would be followed by a four-year “circle of the moon” to “reduce” its speed so it can orbit its target – the Enceladus Orbilander requires a super launch vehicle. heavy. This likely means NASA’s Space Launch System (SLS), although it could also mean the SpaceX Starship vehicle. Both are still in development.

However, it could be launched on a heavy lift vehicle – like the SpaceX Falcon Heavy – if it also included a solar-electric propulsion stage and/or Jupiter gravity assist. Assists to Venus and Earth’s gravity would also be possible. But for either one, then we’re talking about nine or 10 years just to reach Saturn.

4. He will seek life

Enceladus is an icy rock world with active plumes of gases and particles coming from its subterranean ocean. Thus, Orbilander will be able to study the materials in its plumes as if it were directly sampling its subterranean ocean for signs of habitability.

The main scientific objectives of Orbilander are:

  • look for evidence of life.
  • to obtain geochemical and geophysical context for life detection experiments.

5. Enceladus is tiny

The main problem with the Orbilander mission concept is that Enceladus is so small. It’s only 311 miles/500 kilometers in diameter, the same distance between London and Edinburgh, so physically breaking out of Saturn’s orbit and orbiting Enceladus won’t be easy.

Cue a four-year lap of Saturn’s moons to slow it down and put it on the right course to intercept Enceladus.

6. It will cost $4.9 billion…that’s $900 million

If NASA just can’t afford to begin development of the $4.9 billion Orbilander mission, it has a plan B from the committee. Also on the list is the Enceladus Multiple Flyby (EMF) concept, a more affordable “New Frontiers” mission costing less than $900 million. EMP is a flyby mission that would require a spacecraft to collect plume samples while traveling at 4 km/s – which is not ideal – and it would gather 100 times less material than Orbilander. The EMF would also lack life detection capability and be unable to provide geological or geophysical context.

If Orbilander starts by 2030, on target, then EMF is history, the 10-year survey report says. “When we generate a 10-year survey, we don’t know what the budget will be over those 10 years, and there are a lot of funding draws,” said Amy Simon, senior scientist for planetary atmospheres research in the division. of Solar System Exploration at NASA Goddard Space Flight Center, and a member of the committee that prepared the report. “While we’d like to see two new Flagships launch over the decade, this may or may not be affordable, so allowing Enceladus to remain in New Frontiers allows for additional flexibility.”

7. Enceladus Orbilander is not guaranteed

Although it has beaten rival concept missions – in particular the Europa Lander, Mercury Lander, Neptune-Triton Odyssey Flagship and Venus Flagship – Orbilander is only the second highest priority flagship mission after the Uranus Orbiter and Lander.

Given that NASA has already embarked on the Mars Sample Return mission to fetch the rocks currently being collected by its Perseverance rover – and that the Uranus orbiter and lander were ranked third in the 2010 decadal survey and were never built – the chances of Orbilander becoming a reality still hang in the balance.

“Orbilander offers a unique opportunity to explore the astrobiological conditions of ocean worlds and will revolutionize our understanding of these worlds,” the Decadal Survey report states.

It must be worth the wait.

I wish you big eyes and clear skies.

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