Issue No. 231

The Orbital Index

Issue No. 231 | Aug 16, 2023

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MMX. In late 2024, JAXA plans to launch its Martian Moons eXploration (MMX) mission to explore Phobos and Deimos. The mission will initially fly by Deimos and then, ambitiously, drop a rover on Phobos for surface exploration, before briefly later landing to collect samples for return to Earth. The 25 kg rover, to be dropped from 50 m above the surface, will be provided by Germany’s DLR and will carry four cameras, a radiometer, and a Raman spectrometer (for mineralogical analysis). The rover will only travel at millimeters/sec to avoid launching itself into orbit against surface gravity which is a thousandth of Earth’s. It may also need to roll over after landing to upright itself before deploying solar panels. It builds on the previous German-French-Japanese collaboration of MASCOT which was dropped 51 meters onto Ryugu by Hayabusa 2. The rover will provide critical data on surface characteristics before MMX itself attempts a sample retrieval during a one-Phobosian-day cycle (2.5 hours from sunrise to sunset) surface landing. If everything goes well, samples will be delivered to Earth in 2029. Science results from the mission will hopefully determine if Phobos and Deimos are fragments of Mars itself, as suggested by data from UAE’s Hope orbiter, or are captured asteroids. (Deimos is slowly moving towards an escape from Martian orbit.) A Russian attempt to return similar samples, Phobos-Grunt, failed to leave Earth orbit after launching in 2011 due to a programming error and re-entered over the Pacific Ocean west of Chile in 2012; it carried a Chinese Mars orbiter and a Planetary Society experiment as well. Related: JAXA is also considering a mission to return samples from a comet.

A striking recent image taken by ESA Mars Express and processed by Andrea Luck shows Mars’s moon Phobos over the red planet. Credit: ESA/DLR/FUBerlin/AndreaLuck

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LAND_NOW. Last month, the seemingly indomitable Ingenuity Mars ‘copter reestablished communications after hilly terrain blocked its connection to Perseverance—which acts as a radio relay for the diminutive helicopter—at the end of its 52nd flight. This comms dropout was expected by flight controllers, and after a 63-day wait, Percy crested the hill, reestablishing communications. Flight 53 was then planned to scout rugged terrain and relocate Ingenuity to a site ~200 meters north. However, 142 meters into this flight on July 22nd, a flight contingency program named “LAND_NOW” was triggered. This is the first time an abort has happened while in the air, although a Sept ’21 flight (#14) was aborted before takeoff due to a failed “servo wiggle” test. This in-flight abort was likely due to frames from the nav camera not aligning with data from the IMU, potentially because the nav system dropped some frames. This first happened during flight 6 and caused what might’ve looked like a good ol’ bob-and-weave maneuver. A patch was applied after flight 6, but flight 53 may have experienced more dropped frames than the updated software could handle. Fortunately, subsequent flight 54, a 25-second up-and-down hop executed on August 3rd to test the rotorcraft after the abort, went off without a hitch. Here’s to many more Mars helicopter flights!

A photo taken during Ingenuity’s 54th flight, a 25-second hop test after flight 53 ended in a mid-air abort. (Can you find a certain rover in the picture?)

China launches first GSO SAR sat. China launched the world’s first known SAR satellite operating in geosynchronous orbit—it will look through cloud cover, allowing China to monitor natural disasters and provide better-targeted relief operations, especially in the case of flooding. The satellite will produce 20-meter resolution imagery of the Chinese mainland while likely following a figure-8 shaped (an analemma) ground track (aka an inclined geosynchronous, but not geostationary, orbit). High orbits pose a challenge for synthetic aperture radar since they require long synthetic aperture integration times producing decoherence and increasing the complexity of signal integration/processing algorithms (paper). Developed by CAST and named Ludi Tance-4 (01) (translated “Land Exploration”), the satellite launched on a Long March 3B last Monday. The “(01)” designation could point to plans for additional geosynchronous SAR sats (although none are rumored/announced) and represents a separate project from China’s Gaofen/CHEOS optical observation GEO constellation. (Related: Due to NOAA easing restrictions on many US-based commercial remote sensing licenses, Umbra was recently allowed to produce 16 cm SAR images, the highest resolution ever released by a commercial satellite.)

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News in brief. The first crewed Starliner is now set to launch no earlier than March 2024, with a drop test for its updated parachute design slated for November Propulsion systems, and now maneuver planning, provider Benchmark Space Systems closed a $33M Series B Virgin Galactic’s space plane VSS Unity launched with its first space tourists—and, for the first time, women outnumbered men on a spaceflight Amazon’s David Limp, who managed their devices programs including the massive Project Kuiper, has retired EO data management startup Tilebox raised $1.7M Rocket Factory Augsburg raised $32.9M to finish their spaceport in Scotland SpaceX announced that it will now offer mid-inclination “Bandwagon” rideshare missions in addition to their popular sun-synchronous Transporter missions Telesat swapped satellite manufacturing suppliers (Thales to MDA) to save ~$2B for their Lightspeed internet constellation Luna-25 launched toward the Moon on a Soyuz 2.1, Russia’s first lunar lander in 47 years (c.f. our last issue) and is currently projected for an August 21st landing Chandrayan-3 completed another lunar-orbit reduction burn and will enter a 100 km circular polar lunar orbit tomorrow, ahead of a landing attempt next week (projected two days after Luna-25) China launched the FENGYUN-3F satellite, becoming the only country to possess meteorological satellites in early morning orbit, morning orbit, afternoon orbit, and non-sun synchronous orbit JWST used gravitational lensing to capture more details of Earandel, the oldest star ever observed

Earendel (a catchier name than WHL0137-LS, Old English for ‘morning star,’ and borrowed by JRR Tolkien for the mythology of Middle Earth) is the furthest individually-resolvable star known, only visible due to gravitational lensing. It is between 50 and 100 solar masses and we’re viewing it at 900 million years after the Big Bang


The Galle Crater deposit pictured below contains multiple unconformities (gaps in the geologic record represented by sudden or irregular changes from one deposit to another), indicating periods of erosion and non-deposition. The crater’s geologic history is not well constrained, and it contains a variety of features that have been interpreted as fluvial (river), lacustrine (lake), or glacial deposits. Credit: NASA/JPL-Caltech/UArizona

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