¶DART. NASA’s Double Asteroid Redirection Test (DART) experimental planetary defense mission was scheduled to launch last night on a Falcon 9 (at the time of writing). When it slams into the 170-meter wide Dimorphos asteroid (aka Didymoon) in the Didymos binary system at 6.6 km/s, the 650 kg DART will hopefully become the first kinetic impactor to change the motion of an asteroid. While the impact in 2022 will only change Didymoon’s velocity by about half a millimeter per second, it will change the orbital period by ~10 minutes—enough to be measured from Earth. This measurable change will start to answer questions about how a much larger version of the technology could be used to redirect an asteroid. Before its demise, DART will also demonstrate Roll Out Solar Arrays (ROSA) and an upgraded ion engine based on the one used by Dawn. It will be accompanied by LICIACube from the Italian Space Agency which will attempt to capture images of its final moments. DART will be followed by ESA’s Hera mission, arriving at Didymos about four years after DART’s impact. Hera and its two CubeSats—APEX and Juventas—will study the pair of asteroids and the aftermath of the impact. Hera will test autonomous navigation, coming within 200 m of the surface of Didymoon and taking pictures with a resolution down to 2 cm/pixel. Juventas meanwhile will map the interior structure of Didymoon with radar and end its mission by attempting to land on the moon (in a sort of slow-motion crash and bounce maneuver at a few cm/s). |
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¶Lucky Number Seven. Last weekend, Astra’s seventh “Rocket 3” launch vehicle (LV0007) successfully reached orbit (video) making the company one of very few to do so with a privately developed rocket. The 13-meter tall rocket—stretched 1.5 m to include larger tanks after LV0005 ran out of gas just shy of orbit—can carry up to 150 kg into SSO using its five 3D-printed Delphin engines. These 29 kN engines are electric pump-fed, similar to Rocket Lab’s 25 kN Rutherford engines. Meanwhile, the upper stage is powered by a single pressure-fed, vacuum-optimized Aether engine. (News broke recently that Astra secretly purchased rights to Firefly’s engine technology, although their eventual application is still unclear.) This launch, from the Pacific Spaceport Complex in Kodiak, Alaska, carried a mass simulator payload for the US Space Force, but the company hopes to begin launches of live payloads for paying customers in early 2022—launch vehicles eight through ten are in production and will start to roll off the production line monthly. (Related: The company also recently filed an application with the FCC for a 13,000 satellite internet service mega constellation, but would like us all to stay focused on the launch for right now.) |
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 | T-0 as Astra’s LV0007 takes off, destined for orbit. Photo Credit: Brady Kenniston/Astra |
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¶Papers. - Phosphorus tends to settle into the core of a forming planet, so the phosphorus in our bones and DNA was likely brought to Earth either by meteors or cosmic dust. New evidence suggests that fiery ablative interaction with the Earth’s atmosphere converts the element into biologically useful forms which eventually settle onto the surface (paper).
- For the first time, we’ve spotted clear evidence of an exoplanet having been impacted by a massive protoplanetary body, spewing out dust and blowing away part of the planet’s atmosphere, similar to what may have happened when our Moon formed. The star system, 95 light-years away, is surrounded by suspiciously planet-rich dust and gas. The collision “likely occurred between a roughly Earth-sized terrestrial planet and a smaller impactor at least 200,000 years ago, at speeds of 10 kilometers per second” (paper).
- Speaking of which, a new paper in Geology suggests that a glassy deposit covering a 75 km stretch of the Atacama Desert in Chile is not the result of historical wildfires, as previously assumed, but rather is due to a cometary airburst event ~12,000 years ago. This is supported by evidence of the material having been violently deformed while melted, an elemental composition that looks more extraterrestrial than terrestrial, and glassified minerals that have melting points hotter than a grass fire could generate. As with other stories of historic airbursts, we take this with a grain of salt. 🧂
- Meanwhile, imagine we spot a dangerous asteroid on a collision course with Earth when it’s only days or hours away? It’s far too late to use something simple and elegant like DART or a gravity tractor, or even to blow it up and have enough of the fragments miss the Earth. Our best option, according to a new analysis (detailed pdf), is to launch an array of rods (e.g., a 10x10 array of multi-meter long hardened penetrators, some containing explosives) into the asteroid’s path, using its relative velocity to pulverize it into a cloud of fragments that can then burn up in the atmosphere, causing a bunch of uncorrelated smaller airbursts instead of a single large catastrophic one. The paper found this to be surprisingly effective. Existing launchers could easily deliver 100 penetrators, or 10 tons, into an asteroid’s path, and Starship with refueling could deliver 100 tons, enough to “take on asteroids well in excess of 100 m diameter with a goal of mitigating an Apophis-class (370m diameter) asteroid.” 💥
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¶News in brief. JWST’s launch was pushed back by a few days to NET December 22nd to allow for additional testing after a clamp released unexpectedly while attaching the telescope to its launch vehicle adapter and “caused a vibration throughout the observatory” 😬 ● Rocket Lab’s Love at First Insight launched two BlackSky sats (video) ● The US Space Force is buying three more GPS IIIF satellites from Lockheed Martin ● NASA awarded Intuitive Machines a CLPS contract for a 2024 lunar landing of their Nova-C lander carrying 92 kg in four payloads, including the Lunar Vertex suite and its rover, and the four CADRE rovers that are ‘programmed to work as an autonomous team’ to explore the Reiner Gamma swirl on the lunar surface ● Sierra Space raised a $1.4B “Series A”—about 2⁄3 for continued development of their Dream Chaser Spaceplane and 1⁄3 for their inflatable LIFE habitat as part of Orbital Reef, their proposed commercial space station project with Blue Origin (spinning off a 1,100 person company and then calling its billion+ mega-round a Series A feels like a stretch 🤷) ● ThrustMe demonstrated an iodine-fuelled electric propulsion module in space—iodine is cheaper than xenon, easier to ionize, and can be stored as a solid, leading to miniaturization and ~50% better efficiency, but it’s corrosive, so surfaces it touches were ceramic coated ● South Korea announced that their next rocket to be developed will be reusable ● Blue Origin announced the riders on their next New Shephard mission ● Axiom Space teased a new spacesuit design ● China launched yet another new remote-sensing satellite (its record 42nd launch of the year) ● Inversion, an LA startup, raised $10 million to develop orbital cargo return capsules. |
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 | On the other hand, who needs orbital cargo return when you can have orbital people return? MOOSE, the Man Out of Space Easiest, was proposed by General Electric in the 1960s. 😂 |
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¶Etc. - Elon gave a Q&A about Starship (video). A few highlights: they expect FAA approval this year, with a 1st orbital flight attempt early next year (which will likely blow up); they hope to do about 12 test launches in 2022 and to start selling launch contracts in 2 years.
- Visualizations show the extensive cloud of debris Russia’s anti-satellite test created.
- NASA’s Small Spacecraft Systems Virtual Institute recently released some handy smallsat materials, including their updated State-of-the-Art Small Spacecraft Technology 2021 document, Space Mission Design Tools page, and Small Satellite Parts On-Orbit Now (SPOON) COTS parts database.
- NEO Surveyor, NASA’s other upcoming Planetary Defense mission, designed to find 90% of near-Earth objects with diameters of at least 140 m, entered its preliminary design phase at JPL in June. It will hopefully launch in 2026. Over the last 10 years, NASA’s spending on Planetary Defense has increased 4,200%, although it’s still only 0.7% of the Agency’s budget.
- Juventas’ compact radar, which will peer up to 100 m deep within the 160-m-diameter Didymoon in 2026 or so, will be the smallest radar system flown in space. It was recently tested at ESA’s European Space Research and Technology Centre (ESTEC) in the Netherlands.
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 | ‘GENERAL JAN DODONNA: An analysis of the plans provided by Princess Leia has reinvigorated the arguments of the 'artificial moonlet' and 'rogue planet-station' camps. I fear this question is fracturing the Rebellion.’ (XKCD 1458) |
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