Space Sunday: a bit of JUICE, a flight test & celebrating 50

What is widely regarded as one of the most important space missions has been successfully launched to much acclaim and excitement.

No, I’m not talking about the SpaceX Starship / Super Heavy orbital test flight – of which more anon – but that of the European Space Agency’s JUpiter ICy moon Explorer (JUICE) spacecraft, a 1.6 billion Euro (US $1.7 billion) mission designed to gain a more thorough understanding of Jupiter’s three major icy moons – Europa, Ganymede and Callisto.

JUICE started life in 2008 as part of a joint NASA/ESA mission which had the rather clunky name of Europa Jupiter System Mission – Laplace (EJSM-Laplace), a US $4.7 billion mission to study Jupiter’s moons with a focus on Europa, Ganymede and on Jupiter’s magnetosphere. The mission would have comprised at least two independent elements, NASA’s Jupiter Europa Orbiter (JEO) and ESA’s Jupiter Ganymede Orbiter (JGO), with the potential for involvement on the part of Japan and Russia.

By 2011, it was clear to ESA that NASA would not have the budget to fulfil its part of the mission by the 2020s, and the JGO element morphed into JUICE, which was selected for the agency’s first L-class mission in May 2012, with ESA being proven correct in regards to NASA’s involvement in EJSM-Laplace in 2015, when the US agency reformulated its plans into the Europa Clipper mission.

JUICE was launched on 14 April 2023 at 12:14:36 UTC on the penultimate flight of an Ariane 6. The launch has been delays by 24 hours due to weather concerns, but on the 14th, the launch vehicle lifted-off smoothly, the satellite successfully separating from the rocket’s upper stage some 26 minutes after launch prior to commencing an internal systems check, after which it was due to ‘phone home and say, “Hi there!”

This call came a little later than the mission plan had estimated at some 40 minutes after launch, but still within the overall expected time frame. Following confirmation from ground control, the 6-tonne space vehicle deployed its 27-metre spans of solar arrays, completing the task a little ahead of schedule, reporting the arrays to be fully deployed and active.

The deployment marks the start of a complex 8-year coast to Jupiter which includes four gravity-assists from the inner planets to both boost the spacecraft’s velocity and to help swing it onto the required trajectory required for a successful Jupiter rendezvous (and a possible fly-by of the asteroid 223 Rosa in October 2029. These flybys will comprise:

• August 2024 – a return to Earth, using both the Moon and Earth to accelerate and adjust course. This will be the most accurate gravity assist manoeuvre ever carried out by an interplanetary vehicle.
• August 2025 – a flyby of Venus whilst travelling around the Sun, again accelerating the spacecraft whilst angling it onto a trajectory that will see it swing by Earth
• September 2026 a second flyby of Earth (confusingly called “Earth flyby I”, which will throw it out into the solar system almost as far as Mars before it swings back around the Sun.
• January 2029 – a third flyby of Earth (“Earth flyby II”) which will slingshot JUICE on a two year journey to Jupiter, with the possible asteroid flyby along the way.

On arrival in the Jovian system, in July 2031, JUICE will first perform a flyby of Ganymede in preparation for Jupiter orbital insertion about 7.5 hours later. This will place the vehicle in an elongated orbit around the planet, allowing it to perform some 35 flybys of the target Moons. The orbit around the planet will gradually becoming more circular over time, and will have an inclination that will allow JUICE to also study Jupiter’s Polar Regions and its magnetosphere.

The flybys will allow JUICE to observe its targets over a 3.5 year span of time, with a major focus on Europa. However, in December 2034, the focus of the mission will shift as JUICE enters an extended, 5,000 km elliptical orbit around Ganymede. This will be rapidly circularised to 500 km in 2035, allowing the vehicle to carry out an in-depth study of Ganymede’s composition and magnetosphere.

It is anticipated that the vehicle’s fuel reserves will be depleted to a point where accurate guidance and manoeuvring cannot be maintained by the end of 2035, and the last remaining reserves will be used to impact the craft on Ganymede at the end of that year or possibly very early in 2036.

The primary aim of the mission is to more fully characterise the overall surface and (particularly) sub-surface conditions on (notably) Europa and Ganymede, and also on Callisto. As regulars to this column (and to space exploration in general) will know, Europa is believed to have a surface crust of ice covering what could well be a deep liquid water ocean, heated and kept in a liquid (or near-liquid) state by the moon being constantly “flexed” by the gravitational influences of the other Galilean moons as they orbit Jupiter, and Jupiter itself.

With this in mind, JUICE will specifically study Europa to understand the formation of surface features and the composition of the non-water-ice material. In particular, it will attempt to gather information on any chemistry essential to life which may be present on Europa’s surface, including organic molecules, and it will carry out the first sub-surface soundings of the moon in order to try to determine the thickness of the icy crust over the most recently active regions of the moon, and attempt to gain a clearer understanding of what lay beneath it – such as liquid water or icy slush.

While further away from Jupiter and with a more one-side “pull” being exerted on them, it is believed that both Ganymede and Callisto might also have oceans of liquid water (or perhaps icy slush) under their surfaces, so the main science objects for these moons – with the particular emphasis on Ganymede comprise:

• Characterisation of the ocean layers and detection of putative subsurface water reservoirs.
• Topographical, geological and compositional mapping of the surface.
• Study of the physical properties of the icy crusts.
• Characterisation of the internal mass distribution, dynamics and evolution of the interiors.
• Investigation of Ganymede’s tenuous atmosphere.
• Study of Ganymede’s intrinsic magnetic field and its interactions with the Jovian magnetosphere.

In all, the information gathered on the three moons should help scientists better assess their potential as havens of basic life within any warm oceans which may exist within them.

I think this is something that Europe can be extremely proud of. This is a mission that is answering questions of science that are burning to all of us.

– Josef Aschbacher, ESA Director General

The launch was the sixth Ariane 5 flight to carry an ESA mission, a total that includes the December 2021 launch of NASA’s James Webb Space Telescope that features significant ESA contributions. It was the 116^th Ariane 5 launch overall, dating back to 1996. However, it was also the last flagship mission launch for the ESA workhorse; after an upcoming launch of two communications satellites, for the French and German governments respectively, Ariane 5 will make way for its Ariane 6 successor, with the first launch of the new rocket – which has had a troubled development cycle – is due towards the end of 2023 or early 2024.

Starship / Super Heavy Orbital Test Flight

The other big news for the week is that the Federal Aviation Administration (FAA) granted the long-awaiting license for the first orbital flight attempt of the SpaceX Starship / Super Heavy – although the exact date for the flight is not entirely clear.

The FAA issued the license on April 14th, for the launch from the company’s Starbase test site in Boca Chica, Texas. The launch window opens at 13:00 UTC on Monday, April 17th, and extends through until 14:30 UTC that day. This has led to a fair amount of speculation that the launch will come on the 17th – which is the date SpaceX are currently aiming for, although the license covers a period through until April 22nd, and SpaceX CEO Elon Musk has suggested the launch attempt could come more towards the end of the week than the start, possibly anticipating issues during any attempt on Monday that might call a halt to things are require a re-try.

In the meantime, and following stacked tests, Ship 24 was removed from the top of Booster 7 on the Orbital Launch Mount, allowing engineers to install the Flight Termination Systems (FLS). These are the packages which can be used to destroy the vehicle during flight if it veers off its intended flight track or suffers some other anomaly. FTS units have a limited battery life – around 30 days – again indicating that even if not on April 17th, the launch attempt will be relatively soon.

With the granting of the license, SpaceX has issued an updated mission plan for the flight which includes some differences to the originally-stated flight test. Most notably, Ship 24 will not use its engines during descent at the end of its flight to slow itself or swing itself into an upright position for a “soft” landing in the ocean off of Hawai’i, but will instead literally belly flop into the water.

The overall flight is expected to last 90 minutes from launch through the Ship 24 hitting the water – assuming things proceed smoothly; as a first time flight test, nothing is guaranteed. Highlights include:

• + 00:00:55: Max Q (Moment of Peak Mechanical Stress on the Rocket).
• +00:02:49: Booster 7 Main Engine Cut-Off.
• +00:02:52: Ship 24 separates from Booster 7.
• +00:02:57: Ship 24 engine ignition.
• +00:03:11: Start of Booster 7 Boost Back burn.
• +00:04:06: Booster 7 Boost Back burn shutdown.
• +00:07:32: Booster 7 in transonic descent.
• +00:07:40: Booster 7 landing burn start-up
• +00:08:03: Booster 7 landing burn shutdown.
• +00:09:20: Ship 24 engine cut-off; coast phase of orbit commences.
• +01:17:21: Ship 24 enters the denser atmosphere.
• +01:28:43: Ship 24 in transonic descent.
• +01:30:00: Ship 24 hits the water.

Splashdown for Booster 7 should occur around 32 km off the Gulf of Mexico coast, and for Ship 24, approximately 100 km off the northwest coast of Kauai. During its flight, Ship 24 will not complete a full orbit of Earth, but it will reach what is being termed orbital velocity — for low Earth orbit, about 28,160 km/h — at an altitude of approximately 240 km, if all goes according to plan.

It is not clear if the flight will carry a dummy payload or not – SpaceX have a habit of launching odd loads during test  / initial flights, with past examples being a wheel of cheese and (most famously) the Tesla Roadster launched on the first flight of a Falcon Heavy. Whilst neither the booster nor the starship will be recovered, the test is seen as an important proof of concept for the system, with further flight tests to come in due course.

Further Starship vehicles and Super Heavy boosters are currently being fabricated and assembled at Boca Chica – although FAA flight restrictions under the PEA, only 5 orbital flight attempts are allowed per year. This – unless changed – would tend to put a little bit of a crimp in plans to move the system towards an operational status; however, SpaceX appear to be unwilling to step away from what appears to be an aggressive approach to Starship / Super Heavy flights.

Beyond that, and as I’ve mentioned, there are a number of major hurdles SpaceX need to clear to prove the Starship / Super Heavy system is viable. As I’ve also noted, I hope to take a look at the potentials and pitfalls of the system in the near future.

In  the meantime – and should the launch attempt take place on Monday – it can be viewed via You Tube:

Ingenuity Reaches 50

It is the little helicopter that could – and still can.

Delivered to Mars by the Perseverance rover as a part of NASA’s Mars 2020 mission, the Ingenuity drone helicopter was originally intended to make just 5 planned flights and act as a proof of concept for using small aerial vehicles on Mars.

However, in the two years since then, the little vehicle has proven itself to be more than just an experiment but a vital part of the overall Mars 2020 mission, becoming a set of airborne eyes for Perseverance whilst demonstrating the potential UAVs could provide eventual human missions on the surface of the Red Planet.

On April 13th, 2023 the helicopter achieved a new milestone, notching up its 50th flight, and did so in style. The 1.8 kg vehicle lifted-off on a 146-second flight in which it reached a altitude of 18 metres above the ground – higher than it has eve previously flown, and six times higher than it’s first flight on April 19th, 2021.

Since that first hesitant up-and-down flight, Ingenuity has continuously pushed its own envelope, carrying out more and more complex flights and carrying out a broad range of roles in helping to guide Perseverance in its missions, spotting routes for the rover to take and noting points of potential scientific interest for the rover to explore. More recently, the helicopter has been helping engineers determine how best to use the drones planned to assist in the upcoming NASA/ESA Mars Sample Return mission which is due to collect sample of subsurface materials gathered by Perseverance and return them to Earth for analysis.

As well as having its flight capabilities extended, Ingenuity has also had its systems and capabilities routinely updated. These updates include having its terrain following navigation system updated to allow it to fly at higher altitudes and to navigate over low hills and along shallow valleys, while more recently, it received a “mitigation capability”, allowing it to identify alternate landing sites along its flight path and evaluate them, should it reach a planned destination in a flight and determine it as being too dangerous for a landing.

She has blown out of the water any sort of metric of success. It’s not just a statement of our reliability design, but it’s also a statement about the technicians that can assemble this thing, right? The team has really done miraculous work that will help in getting two sample return helicopters flying on Mars a few short years from now.

– Theodore Tzanetos, Ingenuity team lead

It’s impossible to predict how long Ingenuity will continue to fly, although it remains in excellent health. Outside of unforeseen failures or accidents, The only potentially life-limiting consumables are leg dampers designed to soften each landing, the ability of the solar panels to harness enough sunlight to recharge the helicopter’s lithium-ion batteries, and the ability of the batteries to hold their charge and power Ingenuity.

As it is, the loss of the leg dampeners can be compensated for by adapting the helicopter’s flights and landing zone selection to avoid harder, heavily landings. Meanwhile, the regular flights have prevented excessive dust build-up on the solar panels, and the battery system remains within about five millivolts of where it needs to be. As such, while all of ingenuity’s flights are carried out one at a time with the view of it potentially being the helicopter’s last, the team are hopeful they can continue notching up flights and successes.