Two spacecraft are set to make lunar milestones, a celestial spyglass with an Israeli angle, the Martian day length holds surprises, and the Starship malfunctions saga continues. This Week in Space

Approaching the Moon

This week, Chandrayaan-3, India's lunar mission, makes significant progress towards its landing near the moon's south pole.  The Vikram lander has separated from the final module of its launch rocket. This propulsion module has carried the lander since its launch on July 14th, put it into lunar orbit, and will continue to orbit the moon and serve as a relay station for the lander. Following the successful separation, the Indian space agency announced that the landing attempt will take place on August 23 (Wednesday) near the moon's south pole. The lander, roughly the size of an average family car, carries with it a small rover, Pragyan ("wisdom" in Sanskrit). After landing, both are expected to operate for about two weeks, probing the lunar surface for its composition and physical properties, particularly hunting  for traces of frozen water, as suggested by research.

The Russian spacecraft Luna-25, launched last Friday, has also entered lunar orbit as planned this week. The Russian space agency, Roscosmos, published a relatively low-quality photo taken by the spacecraft from a distance of about 310,000 kilometers from Earth, before it entered lunar orbit. The image shows Earth and the Moon alongside a part of the spacecraft itself. Russia has yet to announce when the spacecraft will attempt to land. According to the original plan, the landing was supposed to take place 5-7 days after entering lunar orbit, so it seems that the planned date will be very close to the Indian landing attempt. Unlike the Indian lander, the Russian one is expected to operate on the moon for a longer period. Its research objectives are quite similar, and its instruments will also focus on searching for evidence of ice.

A private American company is also expected to join the race to the moon's south pole by the end of the year. Intuitive Machines announced this week that its spacecraft will be ready for launch in September. However, due to SpaceX's busy launch schedule, it seems the launch could only take place in November. The company responded earlier this year to NASA's request to change its mission plan and move the landing from the moon's equator to the south pole area, where Artemis' manned landings are also planned. Although the change resulted in a few months’ delay, no privately-owned spacecraft has landed there yet, and the last attempt resulted in the crash of a Japanese lander in April this year. Therefore, IM-1's mission still stands a chance of making the first successful private moon landing.

Closing in on the target. Earth (left circle) and the Moon (right circle) photographed by the Luna-25 spacecraft on its way to a landing attempt at the moon's south pole. Source: IKI RAS.

The Japanese Telescope and the Israeli Angle 

The Japanese space agency, JAXA, is set to launch its new space telescope, XRISM, in about a week. This is an X-ray telescope intended for exploring questions related to the composition of matter in the universe, such as how galaxy clusters developed, how matter dispersed in the universe (the ‘missing baryons’ problem), and the processes that allow the formation of new elements during stellar explosions, or supernovae. 

This will be Japan's fourth attempt at successfully operating such a space telescope. Already in 2000, Japan has launched the ASTRO-E telescope, but the launch missile exploded less than a minute post-launch.  Its successor, Suzaku, was introduced in 2005, but a malfunction led to the depletion of all its vital helium, essential for cooling the telescope to its necessary low temperature. In its place, Japan launched the Hitomi telescope in 2016, but it disintegrated in space due to a control mechanism malfunction. The current telescope, XRISM, is smaller compared to some of its predecessors and is also equipped with systems designed to overcome certain malfunctions, such as a mechanical backup for the cooling system, which operates independent of helium. 

The XRISM space telescope carries only two scientific instruments: one is the telescope itself, which includes the X-ray sensors and the photography system, and the other is a spectrometer that allows for precise analysis of radiation composition. This spectrometer, a product of a collaborative venture between NASA's Goddard Research Center and JAXA, will offer NASA scientists the opportunity to be the first to use this tool and dissect data collected by it during its initial six months of scientific operation. Subsequently, the global research community will be able to pitch in their requests for telescope observation time slots.                

One of the researchers already awaiting data from the new telescope is Dr. Roi Rahin from Israel, currently undergoing postdoctoral training at the Goddard Center, near Washington. His research focuses on elements created in supernovae, and he expects to employ the telescope to scan for explosion remnants left by a supernova named W49B, located about 26,000 light-years away from Earth. "Preliminary studies observed a peculiar distribution of elements created by this supernova. It seems that one side of the explosion area contains much more iron compared to the other," Rahin told the Davidson Institute website. "With the spectrometer, we can better investigate the distribution of iron-group elements such as chromium, nickel, manganese, and others. By analyzing their dynamics, we hope to understand the phenomenon and processes occurring in such events," Rahin elaborated.

Rahin now works alongside scientists who have been involved for many years in the instrument’s development, and they await its scientific results no less eagerly than he does. "I really hope everything will work. Many people's scientific careers depend on this," he added. "There are also hardly any X-ray telescopes with high spectral resolution active today, and the few that are, are rather old. There are many things we can't see, and once we do, I assume they will provide us with new insights and results different from what we expect. It will be interesting."

 Anticipating surprising answers to fundamental questions about the universe. The XRISM space telescope in Earth’s orbit | Illustration: JAXA.

The Shortening Days of Mars 

The American Mars lander, Insight, completed its operation in December 2022, after four successful years of researching the planet's internal structure. However, even after its demise, the analysis of its data continues to provide surprising findings. A recent study found that Mars' day is shortening, albeit very slowly, likely due to a change in the distribution of the planet's mass. A Martian day, or Sol, is only slightly longer than ours, lasting 24 hours and 37 minutes. The new findings indicate a shortening by 0.00075 seconds for each Earth year.

To make such an accurate measurement, scientists used NASA's Deep Space Network, an array of large communication antennas. They transmitted a radio signal to Mars, which was received by a device named RISE aboard the lander, which then relayed back the signal. Due to the Doppler effect, Mars' rotation slightly altered the frequency of the signal. Multiple measurements were required to calculate the Sol's duration with millisecond precision. “What we’re looking for are variations that are just a few tens of centimeters over the course of a Martian year, which lasts 687 Earth days," said RISE’s principal investigator, Sebastien Le Maistre, from the Royal Observatory of Belgium. “It takes a very long time and a lot of data to accumulate before we can even see these variations.” Indeed, the researchers used data collected over more than 900 days to determine that Mars' rotation is accelerating slightly, causing the day to shorten.

Researchers do not know with certainty what is causing Mars' rotation to speed up. The leading hypothesis is that the acceleration results from a change in the planet's mass distribution. As mass becomes more concentrated closer to the center or the rotation axis, the speed increases, much like a gymnast or a figure skater who brings their arms close to their body in order to spin faster. The researchers speculate that the change in mass distribution results from the accumulation of more ice at the planet's poles, which align with its rotational axis, or from terrestrial motions in the equatorial zones.

 Delving into minute nuances: precise measurements identified a millisecond change in the Martian day's length. A rendition of the InSight lander on Mars' surface. Courtesy: NASA/JPL

Incident Report Update

Four months after the first launch of Starship, which ended in an intentional detonation after the spacecraft failed to detach as planned from the Super Heavy launch vehicle, SpaceX submitted its report on the incident to the U.S. Federal Aviation Administration (FAA),  along with the steps undertaken since to reduce environmental risks. Aside from the explosion damage in the skies of South Texas, the launch itself caused severe damage to the launch pad and its surroundings, leading the FAA to launch an investigation and environmental organizations have filed lawsuits against SpaceX

SpaceX detailed steps taken to prevent a recurrence, including installing a new water deluge system designed to inundate the launch pad. Water sprays are meant to reduce smoke and particle dispersion and to minimize the spread of heat and auditory impact from the launch. The company tested the new system on August 6th and reported positive outcomes. Furthermore, SpaceX mentioned in the report that improvements were made to the spacecraft and rocket's remote detonation system, as during the first test, about 40 seconds passed from its activation until the actual explosion, causing the spacecraft to explode too close to the ground. The FAA will now review the report, and if approved, they could authorize another launch test. As of now, no timetable has been set for this, but according to statements by SpaceX's owner, Elon Musk, a forthcoming launch could take place within 6-8 weeks.

At the beginning it still looked good. Starship upon the Super Heavy rocket after its launch from Texas in April this year, before the separation attempt.

Translated with the assistance of ChatGTP. Revised, expanded and edited by the staff of the Davidson Institute of Science Education