Issue No. 32

The Orbital Index

Issue No. 32 | Oct 1, 2019

🚀 🌍 🛰

¶Musk gave an update in front of SpaceX’s assembled Starship Mk1 airframe. 11 years after its first successful orbital mission, SpaceX presented Starship Mk1, a full-size prototype of their next generation spacecraft. Starship, 3m in diameter and 50m tall, is the largest second stage ever built (it's easy to forget that it’s just a second stage). Mk1 has three atmospheric Raptor engines, with the final version adding 3 vacuum-optimized engines as well, and will reenter the atmosphere in a fall similar to a skydiver, with actuated canards and body flaps to control its descent [video]. Musk is touting its stainless steel construction as a cost and weight savings due to reduced structural and heat shielding requirements. Instead of previously announced transpirational cooling mechanisms, orbital versions of Starship will sport thin, non-ablative ceramic tiles to distribute heat evenly on the windward side of the craft. Due to the steel structure, heatshield tiles are less critical than they were on the Space Shuttle. (The only reason STS-27 wasn’t a disaster was thanks to a steel antenna mount that happened to be behind a damaged heat shield tile.) While the Mk1 prototype lacks some polish [super high-res image showing all the dents and welds… that may crash your computer], versions as soon as Mk3 will use a continuous coil of steel joined by a single seam weld. Starship will sit atop the 68 m tall SuperHeavy, which is now slated to be powered by 24 to 37 Raptors depending on mission, requiring Raptors to be produced at about 1/day—it’s about 8 days per engine right now—which may be a stretch with their many complex components made of high-pressure (~800 bar!) and heat resistant superalloys. The next milestone is a ~20km flight in 1-2 months, and in typical Elon fashion, he said "this is going to sound totally nuts but I think we're going to try to reach orbit in less than six months." (Related: Musk and Bridenstine’s small spat about slipping timelines for Crew Dragon, with the NASA administrator calling out SpaceX, probably due to an impending need to buy more $80 million+ seats from Russia, while Boeing’s very similar timeline has mostly flown under the radar.)

¶NASA is moving forward with their Near-Earth Object (NEO) Surveillance Mission. Based on NEOCam and funded through NASA’s Planetary Defence budget, the new mission is designed to meet a congressional mandate to discover 90%+ of NEOs 140 m in diameter or larger. The mission could launch to the Earth-Sun L1 point in 2025 where it’s sun-shielded IR sensor can see asteroids too dark for visible detection. Given that the congressional mandate has been in place since 2005, this announcement may be, in part, due to July’s near miss by city-killer 2019 OK which passed within 65,000 km of Earth, 0.19 lunar distances, and was only spotted with 24hr of warning. (That last link contains internal NASA emails about the event, because it’s 2019 and BuzzFeed does journalism now.)


¶News in brief.  Virgin Orbit’s air-launched rocket LauncherOne arrived in the Mojave for pre-flight testing, it could launch from their Cosmic Girl Boeing 747-400 aircraft late this year; the final scheduled launch from Site No. 1/5 at the Baikonur Cosmodrome occurred (orbital photo), sending a Russian, an American marine biologist, and the first citizen astronaut from the UAE to the ISS—Site No. 1/5 launched both the first satellite and the first human into space 58 years ago—this is also the final launch of the very successful Soyuz-FG rocket, which is being replaced by the Soyuz 2; a Japanese uncrewed rocket also brought 3777 kg of gear to the ISS, including six lithium ion batteries to replace original nickel-hydrogen ones; after financial troubles, Stratolaunch is hiring again; and, C/2019 Q4 (Borisov) is now known as 2I/Borisov—it's officially an interstellar comet, with a growing kilometer-long comet trail.


Starship Mk1 prototype stands under the Texas stars.

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