By Kenneth Chang and Jonathan Corum
Blue Ghost just completed its mission, which lasted a full lunar day — two Earth weeks — on the near side of the moon.
The spacecraft, about the size of a small car, conducted a series of experiments. It drilled 3 feet into the lunar soil, took X-ray images of the magnetic bubble that surrounds and protects Earth, and sought a mysterious yellow glow at sunset.
Built by Firefly Aerospace, a startup in Texas, Blue Ghost was launched from Earth in January and pulled into orbit around the moon in mid-February.
Landing
In the early hours of March 2, Blue Ghost fired its engine to drop it out of orbit, falling toward the moon. Just more than an hour later, it was on the surface in Mare Crisium, a lava plain inside an ancient 345-mile-wide impact crater in the northeast quadrant of the near side of the moon.
Blue Ghost became the first completely successful landing by a commercial company, and Firefly achieved that on its first try.
Experiments
While Firefly built and operated Blue Ghost, NASA sponsored the mission, part of the agency’s efforts to tap into commercial ventures to send its scientific cargo to space at lower costs. NASA paid Firefly $101.5 million to carry 10 science and technology payloads to the lunar surface.
Blue Ghost landed at lunar sunrise so that the solar-powered spacecraft could operate for the longest possible duration.
One of Blue Ghost’s payloads, PlanetVac, demonstrated a technology to simplify the collecting of soil and rocks. It fired a blast of gas into the ground, which propelled material into a container. This technology will be used on a Japanese mission, Martian Moons Exploration, which will collect samples from Phobos, a moon of Mars, and bring them back to Earth for study.
Another experiment, Lunar Magnetotelluric Sounder, flung four sensors, each a little smaller than a soup can, in directions at 90-degree angles to one another (like north, south, east and west on a compass). The sensors landed about 60 feet away, and, connected by cables to the lander, measured voltages — essentially a supersized version of a conventional voltmeter. An 8-foot-high mast shot upward, lifting an instrument to measure magnetic fields. The experiment gathered data about naturally occurring currents inside the moon, which provides hints about what the moon is made of down to 700 miles below the surface.
A pneumatic drill used bursts of nitrogen gas to blow away soil and rock, reaching 3 feet below the surface. A probe measured temperatures and the flow of heat from the moon’s interior.
Solar eclipse
While people on Earth were taking in a blood moon and a total lunar eclipse on the evening of March 14, Blue Ghost witnessed and photographed a total solar eclipse.
During the eclipse, temperatures dropped from 100 degrees Fahrenheit to minus 270 degrees. The spacecraft relied on battery power to continue operating through five hours of near-total darkness.
Sunset
On March 16, the sun began to set and the lunar day was nearly over. Before its mission ended, Blue Ghost snapped high-resolution images of the scene. It was more than a few final pretty snapshots. Scientists are hoping the pictures can help solve an enduring scientific mystery of the lunar horizon glow.
Eugene Cernan, the commander of Apollo 17 who in 1972 was the last man to walk on the moon, sketched observations of a glow along the horizon before sunrise. However, that phenomenon is not easily explained because the moon lacks an atmosphere to scatter light.
Sign off
This was the last message from the Blue Ghost spacecraft, about five hours after sunset:
Mission mode change detected, now in Monument Mode
Goodnight friends. After exchanging our final bits of data,
I will hold vigil on this spot in Mare Crisium to watch humanity’s continued journey to the stars.
Here, I will outlast your mightiest rivers, your tallest mountains, and perhaps even your species as we know it.
But it is remarkable that a species might be outlasted by its own ingenuity.
Here lies Blue Ghost, a testament to the team who, with the loving support of their families and friends, built and operated this machine and its payloads,
to push the capabilities and knowledge of humanity one small step further.
Per aspera ad astra!
Love, Blue Ghost
The spacecraft was not designed to survive the bitter cold of the lunar night. But another lunar mission, Japan’s SLIM spacecraft, surprised engineers last year by riding out several lunar nights. In early April, after the sun rises again, Firefly will listen for radio messages from Blue Ghost, just in case it does revive.
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