Issue No. 237

The Orbital Index

Issue No. 237 | Sep 27, 2023

🚀 🌍 🛰

Bennu delivery service. The mission succinctly named Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (better known as OSIRIS-REx) delivered its precious ~250g sample of Bennu this weekend. The sample, the largest yet collected from an asteroid in space, and NASA’s first, was delivered by a capsule that screamed through Earth’s atmosphere and landed in the Utah desert under parachute (with some nervy anomalies around the deployment of its parachute system; here’s the landing video stream). Bennu is regarded as a high-risk NEO, and OSIRIS-REx has already taught us critical lessons about this class of Earth-crossing object. For example, when the craft attempted sample collection, it sank half a meter into the object and its blast of nitrogen gas, intended to push regolith into the sampling system, also blasted an 8 m crater into the asteroid and dislodged roughly six tons of rock (here’s an animation). We now know that many NEOs may be piles of rubble, barely held together by gravity and weak cohesive forces, making them harder to outright destroy (paper). (This may also explain DART’s significant impact on Dimorphos.) As we mentioned last week, OSIRIS-REx continued on to its next target after releasing the sample capsule by firing thrusters to avoid Earth by 779 km—it now heads to an encounter with Apophis in 2029. Related: Impressively, OSIRIS-REx was (barely) imaged by ESA’s Optical Ground Station telescope in Tenerife on September 16th when it was 4.66 million km from Earth.

Your package has been delivered. Credit: Keegan Barber/AP

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The Habitable Worlds Observatory (HWO). Recently, scientists and engineers gathered at Caltech to discuss next steps for building the Habitable Worlds Observatory (HWO), a proposed next-generation telescope envisioned to spectrographically analyze the atmospheres of Earth-like exoplanets for oxygen, methane, water vapor, and other signs of life. The HWO, a ~6 m diameter telescope with high-contrast imaging and spectroscopy, was called for by the 2020 Astronomy and Astrophysics decadal survey. To block the brightness of a star and resolve its orbiting exoplanets there are two options: a coronagraph mask that is internal to the telescope, or an external, precisely-free-flying starshade. The starshade is clearly more sci-fi, but for the HWO concept design NASA is taking the more proven coronagraph route, leaning on work already done for the active, deformable coronagraph (pdf) in the upcoming Roman Space Telescope (NET 2027). This technology will need to be improved significantly, however. It will need to suppress 100x more starlight than Roman’s instrument—which will require picometer-level precision for the active deformation. “We estimate there are as many as several billion Earth-size planets in the habitable zone in our galaxy alone,” said Dr. Nick Siegler, chief technologist of NASA’s Exoplanet Exploration Program. “We want to probe the atmospheres of these exoplanets to look for [...] chemicals that could signal the presence of life.” HWO, if approved, won’t plausibly launch before the late 2030s or early 2040s. But we certainly hope it happens.

Type II Kardashev civilizations eventually completely enclose their planetary system in a Dyson sphere because space is way too big to look at all the time.” XKCD #975

News in brief. SpaceX launched and landed a reused booster for the 17th time, setting a new record Maxar split into two separate businesses: Maxar Space Infrastructure for spacecraft manufacturing and Maxar Intelligence for satellite imagery A solid fuel Galactic Energy Ceres 1 failed to reach orbit for the first time after nine consecutive successful launches Blue Origin CEO Bob Smith will ‘step aside’ effective December 4th, with Bezos announcing the next head of Blue as outgoing Amazon hardware executive David Limp NASA is seeking proposals for a U.S. Deborbit Vehicle that will be responsible for safely deorbiting the ISS after its planned retirement in ~2030 Rocket Factory Augsburg (plus AtomosSpace Cargo and Semer) unveiled their Argo space station resupply vehicle that will be submitted to ESA’s Commercial Cargo Space Initiative The FAA is proposing a rule to require controlled disposal of rocket upper stages (a standard already met by most US launches) True Anomaly won a $17.4M Space Force contract to further develop their space domain awareness technology The FCC is requiring more satellite companies (Planet, IceEye) to form agreements with the NSF to mitigate the impact of their satellites on ground-based optical astronomy Sierra Space raised $300M at a $5B valuation So far, ISRO has been unable to contact Chandrayaan-3’s Vikram lander and Pragyan rover after the lunar sunrise on 9/22, but plan to keep pinging until the next lunar sunset on 10/6 The US Space Force took over ownership of a retired NOAA satellite to extend USSF weather coverage over the Indian Ocean Ingenuity flew to its highest altitude yet (20 m) on its 59th flight—we’re quietly hoping for a barrel roll to mark its 60th! 🚁

Ingenuity’s shadow from 20 meters.

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  • Astronaut food has mostly been precooked, dehydrated, and/or packaged and subsequently microwaved or rehydrated since the beginning of the spaceflight era. Actually cooking food in microgravity presents significant challenges, but healthier and more appealing methods of preparing food—including food grown in space—are needed for long-duration missions away from the conveniences of LEO. A great place to start is boiling pasta with a custom-shaped container that employs capillary forces instead of gravity to keep the hot water where it needs to be. 
  • ESA is cultivating kombucha in space to see if these resilient (e.g. able to repair DNA after exposure to cosmic radiation), oxygen-producing cultures will be beneficial for lunar missions and beyond.
  • A NASA review board (pdf) determined that the Mars Sample Return program has almost no chance of happening on schedule and would likely be many billions over budget.
  • JWST’s spectrographic analysis of a ‘nearby’ possible Hycean exoplanet—one with a hydrogen-rich atmosphere and a water ocean-covered surface—detected methane and carbon dioxide and no ammonia (paper). The presence of methane and CO2, without ammonia, supports the possibility of this being a Hycean planet. The observation also miiiiight have detected dimethyl sulfide, which is thought to be a potential biomarker because, on Earth, it is only produced through biological processes. Follow-up analysis will help clarify this detection. K2-18b is 8.6 times the mass of the Earth and is ~124 light-years away.
  • JWST also recently spotted CO2 on Europa in areas where it likely came from the subsurface ocean, an intriguing result that suggests that the moon’s ocean might be more like Earth’s oceans than we thought (paper), with salty water over a rocky seafloor.
JWST’s quick snap of Europa detected crystalline CO2 (white pixels), potentially in areas where subsurface water recently broke through to the moon’s icy surface. Credit: Geronimo Villanueva (NASA/GSFC), Alyssa Pagan (STScI)

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