# The Orbital Index

Issue No. 153 | Jan 26, 2022

🚀 🌍 🛰

 ¶A Martian carbon biosignature? Not content to be overshadowed by the newer, shinier Perseverance, Curiosity has roved and drilled on (for nearly 10 years now). A paper and NASA summary both report (appropriately conservatively) on tantalizing new evidence from the rover of potential biosignatures in Gale crater. Curiosity’s SAM lab heated 24 different powdered rock samples to 850° C, releasing their solid carbon as methane gas. The onboard Tunable Laser Spectrometer then measured the carbon isotopes in that gas and found more 12C than would be expected based on the 12C-to-13C ratio in the modern Martian atmosphere. On Earth, life preferentially uses 12C over the heavier 13C, bioaccumulating it, so that we observe significantly more 12C than 13C in ancient rocks where life grew. Did ancient Martian microbial methanogenesis concentrate this isotope at Gale crater as it built up complex organic molecules? Maybe. Two other hypotheses offer abiotic explanations: one suggests that UV light could have caused CO2 in the Martian atmosphere to form isotopically enriched carbon monoxide molecules that settled to the surface, the other wonders if the isotopes arrived from space when our solar system drifted through a 13C-depleted giant molecular cloud hundreds of millions of years ago. It’s also possible that the Martian atmospheric concentration changed over time for some unknown reason. “On Earth, processes that would produce the carbon signal we’re detecting on Mars are biological,” but we don’t understand the Martian carbon cycle well enough yet to have any real confidence. As with other tantalizing results about microbial extraterrestrial life, this will probably just turn out to be a physicochemical process we don’t yet understand. Or maybe not. 👽🦠
 ¶The latest SSTO entry. Radian Aerospace, founded in 2016 by aerospace industry veterans, is working to be the next entrant in the, so far unsuccessful, pursuit of a reusable single stage to orbit (SSTO) spacecraft. One of the closest previous attempts was the X-33 project, and Radian’s co-founder & CTO, Livingston Holder, ran the Boeing portion of that program during the ‘90s. Radian’s vehicle will be a horizontal takeoff and landing (HOTL) spaceplane, much like the (also in-development) Skylon / SABRE platform, using aerodynamics to rise above as much of the atmosphere as possible before transitioning to rockets. The spaceplane, designed to be quickly reusable, is powered by three in-house ~900 kN cryogenic engines (each about ½ of a Raptor’s thrust) and will be able to carry 5 people along with 2,250 kg of cargo. On the return, it will support up to 4,500 kg of downmass. Over the past 6 years of development, Radian has raised $32M in funding (with a recent$27.5M seed round) and has built and tested a first full-scale prototype engine. This funding is a drop in the bucket of what it will cost to fully develop the platform—the X-33 testbed cost almost $1.3B ($922M NASA + $357M Lockheed) and didn’t yield an orbital test vehicle, let alone the envisioned full scale SSTO VentureStar vehicle. SSTOs, while in many ways the Holy Grail of Earth-based rocket science, are notoriously difficult since without dropping stages, they are always carrying extra weight and/or operating at less than peak efficiency due to Earth’s atmosphere and deep gravity well. “We all understand how difficult this is,” says Livingston Holder—we sure hope so.  ¶News in brief. Loft Orbital won a significant$150M contract to build and operate a fleet of 10 EO satellites for EarthDaily Analytics (that article is also the first usage we’ve seen of condosat to refer to a satellite with multiple hosted payloads)—the satellites’ busses will be based on the ones used by OneWeb ● SpaceX tested their GSE-4 test ground tank to failure with cryogenic liquid nitrogen 🥶💥 ● Two cosmonauts performed a 7hr space walk to install components on the ISS’s new Prichal module ahead of future visiting Russian spacecraft ● Perseverance “shook the heck out of it for 208 seconds” and successfully cleared the pebbles from its sampling mechanism ● A Chinese science satellite was almost struck by debris from Russia’s November ASAT test ● ABL Space Systems had a ‘test anomaly’ that led to the loss of the second stage of an RS1 vehicle—testing failures are inevitable (and to some extent the point)—thankfully, no one was hurt ● Stratolaunch’s Roc, a giant pontoon boat of a plane, has flown for a 3rd time ahead of being a future hypersonic testbed launchpad ● All of the JWST mirror segments have been deployed and on Monday a careful 1.6 m/s thruster firing inserted it into its orbit of L2 🎉 ​​🔭 ● A SpaceX Cargo Dragon returned to Earth with 2,000 kg of science experiments and ISS station hardware for inspection ● Satellogic raised $150 million ● A ULA Atlas V launched two identical Geosynchronous Space Situational Awareness Program (GSSAP) satellites to a near-GEO orbit ● SpaceX won a US Air Force contract for$102M over five years from AFRL’s Rocket Cargo Vanguard program to explore transporting military and humanitarian cargo point-to-point on the Earth via rocket—basically ballistic missile trajectories with aerobraking and retro propulsive landing—sounds crazy, but maybe it could work?