While the US-led Project Artemis programme is suffering continued delays in its attempt to return humans to the Moon – the Artemis 2 lunar orbital mission originally set for late 2024 being delayed until April 2026, while Artemis 3, the first mission to land on the Moon appears increasingly unlikely to meet its planned mid-2027 launch date due a number of reasons, perhaps most notably the current non-existence of the SpaceX lunar landing vehicle and much of the technology required for it to actually work – China’s project to deliver humans to the Moon and establish an operational base there is continues to roll along at a pace suggesting it will be more than ready to meet its initial goal of delivering two taikonauts to the surface of the Moon by 2030.
As I’ve previously covered in this column, China’s route to the Moon – managed by the China National Space Agency (CNSA) – is a lot less technically complicated than Artemis. In some ways it harkens back to NASA’s own Project Apollo of the 1960s and 1970s; at its core, it relies on sending two pairs of vehicles directly to the Moon. The first is the Mengzhou (“Dream Vessel”) crew vehicle, China’s “next generation” vehicle intended to both ferry crews to and from the Tiangong space station (up to 6 at a time) and to and from the Moon (3 at a time). Supported by a service module, Mengzhou is at an advanced stage of development and testing, and could start crewed flights to orbit in 2027.
The other half of the equation is the lunar lander. Called Lanyue (“embracing the Moon”) takes its cues from the Apollo Lunar Module. Designed to carry a crew of two to and from the lunar surface, Lanyue is a two-stage vehicle comprising the actual lander together with a propulsion module.
For lunar missions both Mengzhou and Lanyue are designed to be launched separately and directly to the Moon by China’s in-development Long March 10 booster, with the two craft docking in lunar orbit to allow the transfer of two of the crew to the lander, which will then be assisted in its lunar descent by the propulsion module used to power it to the Moon, before the lander separates to make its powered landing.
This week CNSA took a further significant step towards the goal of a human landing on the Moon by 2030 with the first powered test of Lanyue’s descent motors using a full-scale structural test article of the lander. Whilst only 30 seconds in length, the tethered test successfully demonstrated the integration and performance of key systems, simulating descent, guidance, control and engine shutdown, all of which are critical to undertaking a successful lunar landing.
The full sized test article was hoisted into the air within a special test stand which then lowered the vehicle at a rate consistent with a fall towards the Moon, the test article firing its primary braking / propulsion motors and using its attitude control thrusters, allowing engineers to assess the effectiveness of both systems in maintaining vehicle control. The test concluded with a verification of the craft’s landing and take-off systems and lunar surface contact propulsion shutdown procedures.
For our manned space missions, we must ensure that astronauts land on the lunar surface very smoothly, which necessitates high standards for the lander’s cushioning and performance. Every bit of weight has to play a role in several functions, so we have to achieve ultimate in integrated design and lightweight construction.
– Huang Zhen China National Space Agency (CNSA)
Lanyue still has a multitude of tests to undergo, but given the relatively short development time frame and with several test articles and prototypes already undergoing tests, including simulations of launch vibrations and stresses on the craft, investigations into the craft’s response to the thermal environment of cislunar space, it is not unfair to say its overall development is fairly advanced, potentially putting that “by 2030” deadline well within reach.
Artemis 2 Update
Despite its delays in terms of its original timescales as noted above, Artemis 2 is making progress. The Orion Multi-Purpose Crew Vehicle (MPCV), mated to its European-built Service Module (ESM) was transferred from NASA’s Multi-Payload Processing Facility (MPPF) to the Launch Abort System Facility (LASF).
Whilst at the MPPF, Orion and its Service Module were loaded with propellants, high-pressure gases, coolant and other essential fuels for its upcoming flight. In addition, the crew for Artemis 2 – NASA astronauts Reid Wiseman, Victor Glover and Christina Koch and Canadian Space Agency (CSA) astronaut Jeremy Hansen – carried out the first on-board tests of their flight pressure suits (aka the Orion Crew Survival System suits) with Orion’s life support and communications systems for a variety of simulated ground and flight conditions.
Now it is at the LASF, Orion will be mated to its 13.4-metre launch abort system tower. This is the system which tops the SLS and Orion stack during launch and the initial ascent to orbit. It is designed to propel the crew capsule away from the launch vehicle in the event of an emergency, and steer the capsule from any potential danger, allowing the crew to return to Earth under the Orion’s parachute system.
Once the installation of the Launch Abort System is complete, Orion will be moved to the Vehicle Assembly Building (VAB), where it will be stacked atop its Space Launch System (SLS) launch vehicle. The rocket itself is currently going through its final assembly within the VAB. Once Orion is mated to it, the two vehicles will go through a series of final integration tests in readiness for their launch.
The Artemis 2 mission is currently scheduled for a no later than April 2026 launch date, and will comprise six key phases:
- Launch to a Low-Earth orbit for initial vehicle check-out on arrival in orbit prior to an orbital boost.
- 24-hour eccentric orbit with an apogee above that of typical communications satellites, where further vehicle check-outs are performed and proximity operations with the (detached) upper stage of the SLS launch vehicle.
- TLI (trans-lunar injection) – firing the service module’s main engines to put it on a course for a Moon rendezvous.
- Lunar fly-by – passing around the Moon with a closest approach of around 7,400 km, during which the crew will continue to monitor and test Orion’s systems.
- Earth return trajectory – Orion will use the Moon’s gravity to swing it into a free-return trajectory to Earth.
- Re-entry and splashdown in the Pacific Ocean.
In all, the mission is expected to last some 10 days.
Hubble Images 3I/ATLAS – and guess what? It is a Comet
A couple of Space Sundays back, I wrote about 3I/ATLAS, the third known interstellar traveller to pass through our solar system, and the (frankly silly) idea that that it is an alien probe, possibly sent here on a spy mission.
In that piece (see: Space Sunday: daft alien theories and a space shuttle) I noted that some of the claims about the object being “alien technology” were due to the fact that as an interstellar comet (as initial analysis suggested was the case), it “had no tail”; this despite the fact the object was already developing a gaseous cloud of ejected dust as it started to get warmed by the Sun.
Well, guess what? As it continues to close on Sun in is inward journey through the solar system, 3I/ATLAS has started to develop a tail – and it has been imaged by the Hubble Space Telescope. Given the images were captured at a time when 3I/ATLAS was 3.8 AU from the Sun – some four times the average distance between Earth and the Sun – the fact that it is starting to evidence a tail indicates it is rapidly becoming active under the Sun’s influence.
Tails generally form on comets as they close on the Sun, when the heat and energy of the latter directly affects the surface of the latter, causing it to outgas volatiles – dust, water vapour, etc., – in sufficient quantities that they are caught in the solar wind to form a trail of matter pointing away from the Sun.
Given 3I/ATLAS is still a long way from the Sun, to see it start to form a tail of outgassed material – even if relatively weak in visual terms – would suggest that it has a lot of volatile materials within it which are already being dramatically affected by the Sun’s energy. What’s more, it is entirely possible that this tail will become more pronounced as the object continues to approach the Sun and reaches perihelion.
However, not only does the appearance of this tail on 3I/ATLAS further undermine claims that it is “alien technology”, it offers a means for astronomers to better understand its composition and likely size. Using Hubble’s exceptional resolution, a research team from UCLA led by David Jewitt has been able to estimate how much material 3I/ATLAS is losing now, putting the amount at between 6 and 60 kilos per second at its current distance from the Sun – or roughly the amount of a small car even few minutes – a not significant amount.
The team also attempted to estimate the likely size of the nucleus of the object; no easy task, given the surrounding cloud of outgassed dust. To achieve this, they instead analysed the brightness distribution of the surrounding dust cloud (coma), and concluded 3I/ATLAS has a likely less than 2.8 km across, assuming it reflects only 4% of the light that hits it (similar to charcoal), but unlikely to be less than 0.32 km in diameter.
This size constraint is crucial because it helps astronomers understand the object’s composition and history. Different materials require different amounts of solar heating to begin sublimating, so by observing when and how vigorously 3I/ATLAS becomes active, it’s possible to make educated guesses about what it’s made of. Further, through this analysis of the Hubble images and data, it is possible for astronomers to gain insight into the nature of 3I/ATLAS, and by extension, the stellar system from which it originated, as objects like 3I/ATLAS carry with them the chemical signatures and physical characteristics shaped by alien environments billions of kilometres away – although sadly, it will be extremely difficult to determine where the object actually originated.
Inara Pey: Living in a Modemworld 