Issue No. 83

The Orbital Index

Issue No. 83 | Sep 23, 2020

🚀 🌍 🛰

A brief(ish?) history of Spaceplanes. With China's recent entry into the world of orbital spaceplanes (covered in Issue 81), a history of spaceplanes seems in order. The first spaceplane, better termed a rocket-plane lifting body, was conceived in Nazi Germany, as a way of delivering ordnance to America (but was dismissed due to complexity). However, the first functioning reusable rocket plane was the X-15, initially flown in 1959, which still holds the record for the fastest flight at Mach 6.7. While it also crossed the Kármán Line and reached 107 km, SpaceShipOne has since surpassed the X-15 to claim the top spot at 112 km. After the flights of the X-15 in the ‘60s, NASA studied multiple designs (including small lifting bodies like the HL-10, M2-F2, and X-24) before designing the eventual Space Shuttle Orbiter in the early 70s (HL-10 test flight 📺). Other notable shuttle concepts include the Star-Raker, an SSTO shuttle with a fold-back cockpit design and air-breathing engines for horizontal take-off, and Chrysler's innovative shuttle on a massive reusable ballistic acorn of aerospikes (complete with the all-appealing name of ‘SERV’ and ‘MURP’—see diagram below) that was derived from the HL-10 and would have used air-breathing engines during reentry. Air-breathing engines also featured in the UK's HOTOL, an early-80s horizontal take-off SSTO which was eventually canceled—but has seen continued development as the in-progress Skylon concept. Skylon has produced the closest attempt yet at an air-breathing spaceplane engine: SABRE (cf. Issue No. 4 & No. 36). While the US was building the Shuttle, the USSR was designing and building the Buran, an arguably more capable vehicle (a group of thrill-seekers infiltrated its hanger in 2017 📺). To test Buran's thermal protection system (developed in part with information publicly released by NASA), the BOR series of lifting body reentry vehicles were developed. A BOR-4, while being retrieved from the Indian ocean, was photographed by Australian reconnaissance and subsequently inspired NASA's HL-20 Personnel Launch System—the escape vehicle planned for Space Station Freedom (replaced by the Soyuz for the ISS). The HL-20 was eventually canceled, but it's lifting body design lives on as Sierra Nevada’s Dream Chaser, planned to fly next year. One last vehicle of interest is ESA's in-development SpaceRider, an autonomous lifting body which will land with a parafoil (animation), similar to SpaceX's fairings, and is planned for launch on the Vega-C in 2022. (Note: This history is incomplete and skips some modern spaceplane development, such as the Air Force’s X-37B, and China’s efforts, a thorough review of which is available from The China Aerospace Blog.)

The HL-10 derived MURP sitting atop the reusable SSTO aerospike-powered SERV.

NASA updates Artemis with a price tag. This week saw the release of a Phase I plan for crewed lunar landing in 2024 (pdf). Possibly the most important item was the funding requirements for the plan: a total of $28B over five years for the landing system, SLS, Orion, new spacesuits, supporting ground systems, and robotic landing missions. The human landing system portion, which features the fast track development of a commercial landing system, comes in at $16.2B, exploration systems including SLS & Orion total $7.6B, and new spacesuits come in at $518M. This all comes with the caveat that NASA’s 2021 budget request of $3.2B for Artemis was only met with an initial $600M allocation for 2021: NASA administrator Bridenstine commented (not surprisingly) that without movement towards significant funding during budget negotiations later this year, the 2024 date quickly becomes unattainable. Other highlights in the plan focus on SLS’s upcoming hot fire test as a significant milestone for Artemis I launching in 2021, the crewed Artemis II adding a proximity maneuvering test, and the previously announced commercial robotic lunar missions starting in 2021. One question not resolved by the plan is whether Artemis III in 2024 will include a stop at Gateway (currently scheduled to launch in 2023, likely on a Falcon Heavy), or will be conducted as a direct-to-surface mission like Apollo. (Related: Kathy Lueders has completed a reorganization of the Human Exploration and Operations Mission Directorate, splitting out crewed Mars mission development from LEO and lunar missions. The reorg also included Gateway as a “key” Artemis resource, showing the agency’s renewed commitment to that station.)


Sarlacc Pit.

News in brief. The first industry contract for ESA’s Hera planetary defense mission was awarded—Hera will follow several years behind NASA’s DART mission to determine if Dimorphos’ (‘Didymoon’) orbit was perturbed by DART’s high-speed impact (review 📺) and will also carry deep space cubesats; China launched a Long March 4B carrying an ocean observation satellite from Jiuquan; NASA and NOAA announced that the solar minimum occurred in Dec 2019, and we’re now officially in Solar Cycle 25—the next predicted maximum is in July 2025; two suborbital launches happened in quick succession from southern Australia last week, with Southern Launch firing two small DART vehicles from T-Minus Engineering on suborbital polar trajectories (too many 🎯-inspired mission names!); Microsoft announced Azure Orbital to compete with AWS Ground Station and other ground station networks—Kubos, Andrew’s old employer, was one of the six featured partners; and, the ISS will be “open for business” by getting astronauts to help film an Estée Lauder ad (and maybe a reality TV show called Space Hero)—we’re unsure how to feel about this.


67P/Churyumov-Gerasimenko as seen by Rosetta. New analysis of signals sent between Rosetta and the unfortunately short-lived Philae lander suggests that solar radiation has significantly changed the comet’s surface (paper).

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