¶Landsat 9. As Vandenberg’s 2,000th rocket to launch, Landsat 9 was carried to orbit by an Atlas V on Monday to replace the 22-year-old Landsat 7. The combined Landsat 8 + 9 revisit time (the period between imaging opportunities for any given location on the Earth) will remain 8 days, unchanged from that of Landsat 7 + 8. Landsat 9 carries two improved science instruments: OLI-2 for observing in visible, near-infrared, and shortwave-infrared light, and the Thermal Infrared Sensor 2 (TIRS-2) for observing in thermal infrared wavelengths (TIRS-2 will also correct a “stray light” issue in Landsat 9’s TIRS instrument). Landsat is the longest continually running Earth-observation program. Landsat data is free and you can even watch it come down in real-time. Also on board were some rideshare cubesats, including CU Boulder’s CUTE which will analyze the composition of exoplanet atmospheres based on transmission spectroscopy of a host star’s light as the exoplanet passes in front. Other rideshares are CuPID, a 6U cubesat that boasts the first wide field-of-view soft X-ray telescope on orbit and will measure x-rays emitted when solar wind plasma hits the Earth’s atmosphere, and Cesium 1 and 2, which will test phased array downlink and inter-satellite links for their customer communications experiment platform. (Here’s a 1/48th scale model of LandSat 9, if you’re into making paper models of nifty satellites for your desk.)
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¶More Marsquakes. On September 18th, having just hit its 1,000th Martian day, NASA’s Mars InSight lander detected a 90 minute long, magnitude 4.2 Marsquake. Along with another magnitude 4.2 quake detected on Aug 25th, these quakes were 5x as powerful as the largest previously observed quake back in 2019. The source of these new quakes isn’t known yet—the one on Aug 25th occurred 8,500 km away, the furthest seen so far, and may come from Valles Marineris, the striking, 4,000 km long, 7 km deep canyon system located on Mars’s equator. Having already used marsquake wave propagation to measure the planet’s thin crust and large molten core, it’s exciting that InSight is continuing to produce observations, even as dust-covered solar panels significantly limit its power budget. As we highlighted previously, the InSight team has been creatively using the lander’s robotic arm to slowly drop sand next to one of its solar panels, letting the Martian wind blow the heavier sand grains across the panel, knocking free lighter accumulated dust. This operation has increased the lander’s power budget by about 30 watt-hours, or 2.4%, per sol (InSight produced 4,588 watt-hours on its first sol, and is now producing just ~27% of that). As always, we also take a moment to marvel at the lander’s seismometer, which can detect displacements at the atomic scale.
¶News in brief. Last week, we missed mentioning that China’s Tianzhou-3 autonomous cargo craft docked with their new station bringing supplies to support its next crew ● Two more Chinese launches occurred Monday—Chinese launch operator EXPACE launched a KZ-1A from Jiuquan with an imaging satellite and a Long March-3B took off with the Shiyan 10 test satellite, but the mission was lost after a nominal flight ● NASA completed umbilical testing of SLS for Artemis I (video) ● Ariane Group will cut about 600 jobs as it works to launch its ~40% less expensive Ariane 6 rocket (which will be in the same size-class as Falcon 9, JAXA’s H3, and Vulcan Centaur) sometime next year ● Starliner’s OFT-2 test flight now appears likely to slip to 2022 ● The FAA’s draft environmental report (pdf) on SpaceX Starship orbital launches is tentatively positive for the eventually licensing of those launches from Starbase in Boca Chica ● At age 90, William Shatner may go to space next month on New Shepard, breaking the record for oldest astronaut set on the last crewed flight of New Shepard by Wally Funk—this flight, currently scheduled for October 12, will also include Planet Labs co-founder Chris Boshuizen and Glen de Vries, of Dassault Systems.🖖
- According to the (somewhat biased) ARK Invest research team, the cost of satellite bandwidth has dropped precipitously since 2004, with $/Gbps decreasing 7,500x from $300M/Gbps to $40K/Gbps. ARK is bullish on a future where Starlink deployed by Starship reduces this cost a further 40x down to the neighborhood of $1,000/Gbps. 🛰 📉 💰
- Jonathan McDowell’s Astronautical Glossary.
- If you’re a university student, you could enter the Over the Dusty Moon Challenge from the Colorado School of Mines to design and build a lunar regolith transport system for construction, mineral processing, and other ISRU activities.
- Also for students, apply for the Caltech Titan Sample Return Space Challenge, a 5-day international mission design challenge next March.
- The region around the ancient city of Tall el-Hammam, located in what is now Jordan, flourished for 3,000 years before suddenly becoming unoccupied around 3,600 years ago. A highly-publicized recent paper suggests that this event was caused by a Tunguska-scale meteoric airburst, killing about 8,000 people and possibly forming the “oral tradition that eventually became the written biblical account about the destruction of Sodom.” As evidence, they cite a transition to salty soils (as if sprayed with Dead Sea water), claims of spherules of shocked quartz, melted mudbrick fragments, glassified pottery, and other signs of destruction (“extreme disarticulation and skeletal fragmentation in nearby humans”). However, other researchers are highly skeptical of these claims, with Scott Manley summarizing and pointing out that some of the same authors published a different paper about a different nearby location also being destroyed by an airburst 10,000 years earlier—the odds are strongly against both being true.
- Scott also recently published a video about Meteor Crater in Arizona, possibly the best preserved meteorite impact crater on Earth. The crater was produced by a 50 m meteorite and yielded a 10-megaton impact, similar in energy to the Tunguska airburst. However, unlike the 1908 event, its iron-nickel makeup let it hang together until impacting the surface.
- Still speaking of impacts, 40 years ago, high concentrations of iridium at the 66 million years old K-Pg boundary (previously known as the K-T boundary) brought a team led by Luis Alvarez and his son to suggest that an impact event wiped out the dinosaurs (and 75% of all plant and animal species). It took 10 years to identify the crater, the Chicxulub impact formation in Mexico’s Yucatán Peninsula, roughly 150 km in diameter and 20-30 kilometers deep. This month marked 30 years since Hildebrand et al’s publication of that identification. 🦖 🦕 ☄️