Issue No. 108

The Orbital Index

Issue No. 108 | Mar 17, 2021

🚀 🌍 🛰

Another round of NIAC. The 2021 NASA Innovative Advanced Concepts (NIAC) awards have been announced, and just like last year, they represent exploratory funding for an exciting collection of futuristic ideas. This year there were 16 Phase I awards, each of up to $125,000. The Phase I solicitation for 2022 will open in June, perhaps you should apply? Also, like last year (1, 2), we’re going to summarize these over two issues.

A high-expansion-ratio auxetic structure can be stowed inside a single Falcon Heavy fairing and deployed to a final length of one kilometer on orbit as part of a large space station.

Approaching debris management. Later this week, Astroscale’s ELSA-d mission will launch from Baikonur Cosmodrome to demonstrate its spacecraft end-of-life management abilities. The mission aims to show that debris can be mitigated by craft like ELSA-d with the addition of a simple docking plate to satellites (mission overview video). The ferro-metallic plates host visual markings which allow ELSA-d and its successors to determine a target’s attitude (based on the reflective characteristics of the plate), perform vision-based target-relative navigation, and finally capture the target magnetically with an extendable docking arm. The 175 kg smallsat will perform multiple captures of its 17 kg deployable target craft, both while the target is under attitude control and in the much more difficult case where it is tumbling (mission ConOps paper). ELSA-d will also demonstrate target search and acquisition, catching up to the out-of-range target using “absolute” ground-based radar data, transitioning to relative navigation, and then performing a walking safety ellipse as part of a safe autonomous approach (here “walking” refers to a slow corkscrew orbital motion that drifts relative to the target spacecraft while staying outside its collision ellipsoid—an explainer video). ELSA-d is specifically targeting End-of-Life (EOL) debris mitigation—including re-orbiting targets to avoid potential collisions—but isn't attempting to address the problem of existing space trash; removing uncooperative trash is termed Active Debris Removal (ADR). ClearSpace One, funded by ESA, will likely be the first mission to demonstrate ADR (but not until 2025), while Phase I of Astroscale’s own ADR mission, ADRAS-J, has been funded by JAXA. ELSA-d will be operated from Astroscale's UK-based control center and recently received final licensing from the UK Space Agency. (And some new debris: the ISS crew recently jettisoned a 2,600 kg pallet of old batteries. It’s the largest mass ever jettisoned from the station and will stay in orbit for 2-4 years before making an uncontrolled re-entry.)

ELSA-d about to capture its unsuspecting quarry.

News in brief. Cosmonauts patched two tiny cracks in the ISS’s Zvezda module which were the source of recent slow air leaks; a Falcon 9 delivered 60 more Starlink satellites and stuck the landing, then three days later, another Falcon 9 did the same thing, completing a record ninth launch and landing on one booster and inching ever closer to the long-time goal of 10 booster reflights; China successfully launched their medium-lift, kerolox-powered Long March 7A for the first time, continuing a slow migration away from hypergolic fuels—the Long March 7A’s first launch in March 2020 failed after first stage separation; China also launched three more Yaogan ocean surveillance satellites; Paraguay's first satellite entered Earth orbit, released from the Japanese Kibo module on the ISS—it will collect data on the habitats of disease-causing insects in Central and South America; Mars InSight is getting ready to use its robotic arm to bury the tether connected to its seismometer in order to minimize the effects of temperature swings on the crazy-sensitive device; meanwhile, Perseverance recorded the sounds of Martian wind and its own lasers zapping; and, NASA is now targeting Thursday for another SLS hot fire test which will require at least 250 seconds of successful burn to move forward.


A 2,600 kg pallet of nickel-hydrogen batteries slowly drifts away from the ISS over the coast of Chile.

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