Blue Ghost (NASA) and Hakuto-R (ispace)

On 15 January 2025, a SpaceX Falcon 9 rocket launched two probes on different low-energy trajectories to the Moon. As of early February, both probes and the second stage of the launch vehicle were in orbits some 200 x 350,000 km, which take them to the distance of the Moon. The probes are as follows:

NASA's Blue Ghost Mission 1 is planned to land on 02 March. On the Moon, the probe will test and demonstrate lunar drilling technology, soil sample collection capabilities, navigation capabilities, radiation tolerant computing, and lunar dust mitigation methods.
ispace’s Hakuto-R M2 Resilience lander will arrive at the Moon in May or June after a four-five month journey. Its orbit will take it past the Moon and out to about 1 million km from Earth before it returns to the Moon to land. The probe carries a five-kilogram micro-rover called Tenacious.

On 01 February, I was able to capture both Blue Ghost and the second stage of the Falcon 9 in separate fields. Hakuto was too faint for me. Blue Ghost was challenging as it was moving about 0.4 arcsecond per second, limiting the exposure time. I took 600 ten-second frames. I found the second stage of the Falcon 9 to be tumbling with a period of about 4 minutes.

Another opportunity to observe the second stage of the Falcon 9 occurred on 05 February, when it was at a distance of 165,000 km. The object was in a 10-day eccentric orbit that takes it from 200 km to 350,000 km distant from Earth. This is very unusual, as most booster stages either deliberately re-enter the atmosphere within hours or are flung into a heliocentric orbit. Predictions from projectPluto.com indicated that the object would be visible at magnitude 12 but moving quickly at some 0.5 arcsecond per second. I elected to take a series of 10 second exposures and found the object to vary in brightness between magnitudes 12 and 15 with a period of 238 seconds (slightly shorter than during the earlier observation).

SpaceX Falcon 9 Carrying Four Probes

At 00:17 on 27 Febuary 2025, a SpaceX Falcon 9 rocket blasted off from Kennedy Space Centre's Launch Complex 39A carrying four probes:

Intuitive Machine's Athena or IM-2 probe bound for the Moon (following just over a year after the company's historic first mission to the Moon),
NASA's Lunar Trailblazer will enter lunar orbit and map ice deposits on the lunar surface,
AstroForge's Odin is bound for an asteroid flyby with 2022 OB5,
Epic Aerospace's Chimera GEO 1 will place cubesats into geosynchronous orbit.

On 28 February, I attempted to image the craft (some or all of them!) The biggest challenge was caused by the poor viewing angle: all the craft were only some 40° distant from the Sun, visible after sunset.

The following image captures the second stage of the Falcon 9, at a magnitude of 15.5-16.0. The stage is white and measures 13.8 m long and 3.7 m in diameter. Athena is considerably smaller, some 4.7 m tall, and the other rideshares are much smaller still. The poor viewing angle meant that only the carrier stage was visible.

On 05 March, with an improved elongation from the Sun (~70°), I tried again to see the Falcon 9. ProjectPluto.com predicted a magnitude of 15.3, which should have been relatively easy to observe, even though motion of the stage would limit exposure times to 10 s. However, I could see nothing in individual images. Tracking and stacking revealed the Falcon 9, but it was very faint: see image below.

But how faint was it? Everything else in the above photo is a streak. However I can estimate the apparent "volume" of the Falcon 9 and compare that to stars of known brightness in another single frame. The composite frame can see about 6.5 magnitudes fainter (2.5*log10(408)) than a single frame. This gives an estimated magnitude of 17.8. If I had known in advance that the Falcon 9 was so faint, I'm not sure that I would have tried to image it! The following is a movie version: each frame is a sum of one hundred 10 s sub-frames.

Nigel Evans