Issue No. 236

The Orbital Index

Issue No. 236 | Sep 20, 2023

🚀 🌍 🛰

Hopper2: success! Last weekend, Stoke Space completed its first 15-second VTVL flight with test hardware (video), flying to 10 m, translating using thrust differential, and landing within the vehicle’s target landing zone. This hop test is a massive accomplishment for the young startup, which is focused on developing a fully reusable small-lift rocket capable of delivering 1.65 tons to orbit with a very high reusability cadence. The hop came after a full wet dress rehearsal and static fire (video) campaign and represented an “icing on the cake” goal for the team. This hopper vehicle has several unique characteristics, including a distributed thrust hydrolox engine (explainer video), hot gas RCS thrusters, and an actively cooled metallic heat shield (pictured below, notice the port in the center of the heat shield which flows fuel over the shield to cool it). With this test complete, the company will now switch its focus to the development of a first-stage booster, which will feature seven methalox engines (methalox feels like it has become the industry norm for new first-stage rocket engines). The first-stage will have return to landing site (RTLS) and downrange (e.g. ship-based) landing capabilities. Related: Interestingly, earlier this year, diverging from the launch startup playbook, Stoke released a software platform developed internally, named Fusion, for tracking complex hardware projects through fast-paced, highly iterative development.

Hopper2, mid hop. 🐇 
Credit: Stoke Space

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Xuntian, a readily serviceable space telescope. The Chinese Survey Space Telescope (CSST), also known as Xuntian (which translates to ‘survey the heavens’), is a 10+ ton, 14 m tall / 23.6 m wide spacecraft planned to launch in December 2024 to co-orbit with China’s Tiangong Space Station at a 340-450 km altitude. The telescope, with its 2 m diameter primary mirror, will image in the visible-ultraviolet wavelengths (255-1,000 nm), imaging galaxy cores, investigating the influence of dark matter, and studying the evolution of the Universe. It is an off-axis (Cook-type) three-mirror reflective optical telescope with carbon fiber housing components. Utilizing techniques demonstrated during the Tianzhou 3 cargo ship port relocation test in April 2022, Xuntian is equipped with multiple thrusters allowing it to autonomously rendezvous and dock with Tiangong’s core module’s forward hatch for repairs and refueling—making it just the second space telescope designed to be serviced in LEO after Hubble. It’s also comparable to Hubble in spatial resolution of about 2.43 gigapixels (thirty 81-megapixel detectors), but promises a 300-350x greater field-of-view, taking images of roughly 17,500 square degrees. When science operations commence in 2025, 70% of the telescope operation time will be dedicated to sky mapping. Xuntian is predicted to image 40% of the sky over its nominal operational lifetime of 10 years, which will likely be extended through maintenance and upgrades. Mounted on the Xuntian platform are 4 instruments: an integral field spectrometer, a multichannel imager, a terahertz receiver, and an exoplanet imaging coronagraph. Xuntian may also be tasked with Earth observation. The mission is a collaboration between teams at the Chinese Manned Space Agency, Peking University, and the National Astronomical Observatories of Chinese Academies of Sciences. The telescope was initially planned to be affixed to Tiangong, but concerns over potential interference from vibration, stray light, field of view obstruction, and contamination prompted its change to be an independent orbiter.  — contributed by Elisa Perednia and Keenan Thompson, who collab on Space Calendar and backyard chickens in Hawai’i.

Xuntian Space Telescope rendering by Changchun Institute of Optics, Fine Mechanics and Physics

OSIRIS-REx returns. Launched in 2016 (almost exactly seven years ago), arrived at Bennu in 2018, booped Bennu in 2020, departed in May 2021, and finally arriving back at Earth in a few days, OSIRIS-REx has been on quite the 7 billion km journey. The craft is scheduled to release its sample return capsule on September 24th, which will then plow through the atmosphere and land at the US Department of Defense’s Utah Test and Training Range. Post recovery, these carbon-rich samples, hopefully chock full of amino acids and other precursors to life, will be delivered to the Johnson Space Center in Houston for careful removal from the reentry capsule and distribution to waiting scientists in the US, Canada, and Japan. Like the Apollo samples, 70% of the material will be archived for future scientists with more advanced technology. After returning its precious samples, the mission will be renamed to OSIRIS-APEX and will head back into deep space until it encounters the 370-meter-wide Apophis in 2029 after the asteroid passes within 32,000 km of Earth. OSIRIS-APEX will enter Apophis orbit shortly after the asteroid’s Earth flyby, getting to observe how the flyby has affected the object and possibly using the spacecraft’s gas thrusters to dislodge dust and small rocks from its surface. .

A map of the asteroid Bennu showing locations of its IAU-named surface features.

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News in brief. Soyuz M-24 successfully docked to the ISS, bringing crew to relieve the crew stranded by M-22’s coolant leaks (who will soon depart on its replacement, M-23) Due to this delay, Frank Rubio set the new NASA record for the longest continuous stay in space (355 days) Germany joined the Artemis Accords Ingenuity flew for its 58th timePrewitt Ridge, a requirements management software startup, raised a $4.1M seed round China’s Tianzhou-5 cargo spacecraft rentered the atmosphere and burned up after a successful CSS resupply mission Varda Space delayed reentry of their in-space manufacturing capsule due to a so-far-denied FAA and Air Force reentry license Telesat announced a 14-launch agreement with SpaceX for their Lightspeed internet constellation Ball Aerospace won a $489.6M NASA contract to build a hyperspectral ocean-and-weather observing infrared sounding instrument for a NOAA geostationary satellite Rocket Lab will launch four additional suborbital hypersonic missions for Leidos Unfortunately, Rocket Lab also had its first launch failure after 19 successful launches in 2 years, failing to deploy a SAR satellite for Capella Space and dropping the company’s stock by 25% Firefly successfully launched a Space Force mission within a 24-hour notice, setting a new record for rapid launch responsiveness (tracking info) Space-traffic startup Kayhan Space raised a $7M seed extensionJWST snapped the supersonic jets of a Class 0 protostar that is analogous to a much younger (just a few tens of thousands of years old) Sol.

“An infantile analogue of our Sun”: This Herbing-Haro object is formed by stellar winds and jets of gas spewed from the protostar, forming shock waves that collide with nearby gas and dust. JWST captured the infrared light emitted by these excited molecules, mapping the structure of these immense outflows.


The longest time-lapse video of an exoplanet shows Beta Pictoris b, a planet 12x the mass of Jupiter, spending 17 years completing almost a full orbit of its star. Six more years of data will complete the orbit.

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