¶The South Atlantic Anomaly & the Van Allen belts. The Van Allen radiation belts are areas in cislunar space where the Earth’s magnetic field captures and concentrates energetic charged particles from the solar wind (while protecting our atmosphere from being stripped away). The Apollo mission trajectories were designed to avoid the worst parts of the belts. A little while ago, Scott Manley dug into the levels of radiation involved—basically, they’re not terrible if you keep moving and you should really worry more about solar storms. The South Atlantic Anomaly (SAA) is an area over Argentina and Brazil where the innermost Van Allen radiation belt dips down to 200 km above the Earth’s surface, creating a region of more energetic particles which can damage LEO satellites. This radiation was likely the initial cause of a cascading series of failures that resulted in Japan’s Hitomi X-ray observatory spinning itself apart in 2016. The SAA moves and evolves as the Earth’s magnetic field changes—it’s currently heading westward and splitting into two lobes. Related: If you’re designing spacecraft, you have to think about how radiation will affect your electronics. Here are some common misconceptions about space-grade integrated circuits. |
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¶The Polar Cusp. Earth’s magnetosphere also has a funnel-shaped gap at the North Pole called the polar cusp that shows up during local noon, when the sun is overhead. The air in this region at orbital altitude is 1.5x denser than normal, causing satellites to experience additional drag. NASA's Cusp Region Experiment-2 is a sounding rocket designed to figure out why. Delayed from 2019 when solar activity was too low, it launched a couple weeks ago from the Andøya Space Center in Norway to an altitude of 630 km. The mission ejected 20 small ampules, each with its own solid rocket motor, designed to open at different altitudes and release vapor tracers to form a 3D grid in the sky and allowing observers to track how air motion distorts the grid over 20-30 minutes. Preliminary reports are that the launch produced good data, so findings will hopefully be released soon. |
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 | Vapor tracers providing colorful, trackable clouds from two rockets in 2019. Here’s another lovely image. Credits: NASA/Lee Wingfield |
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¶NASA iTech. Last week, Ben attended NASA’s iTech biannual space startup pitch event. 2021’s Cycle II event was focused on LEO commercialization, hybrid electric aircraft, physics-based AI, and startups that leverage NASA data for climate resilience. Here’s an overview of the attendees. - Parthain Energy — named after the unexplained Baghdad Battery, Parthain diagnoses the health and quality of lithium-ion battery cells using an electromagnetic sensor. Faster cell testing could reduce the testing phase of battery manufacturing from multiple days of “aging” to hours or minutes, decreasing costs by as much as 10%.
- Cerfe Labs — Cerfe is developing CeRAM, a new kind of non-volatile memory that is radhard, wide-temp (enough to be appropriate for some Venus missions), and scales down past 10nm where DRAM is currently stuck.
- Harmony Aeronautics — excessive environmental noise is a problem in the much-heralded UAV future, caused by propellers running at higher than optimal speeds to match peak motor efficiency. Harmony’s system features a quiet S-shaped propulsor running at lower speeds, matched with an electric motor geared to run at peak efficiency.
- Atmo — a supercomputing startup building affordable solutions for developing nations by first targeting weather forecasting—they’ll start with Uganda’s weather service next year. Only a few (~5) national agencies currently have weather forecasting capabilities due to the challenge of integrating large-scale satellite data with CFD simulations.
- Ten-Nine Technologies — a startup developing a nanomaterial that can be added to battery cathodes to increase peak power delivery. Peak power often dictates battery sizing in aircraft due to high draw during takeoff and landing.
- Astrapi — a startup focused on addressing point-to-point downlink bandwidth limitations using spiral modulation. Requiring hardware changes, it would most likely be applied to spacecraft and ground stations.
- Metocean — an academic team fusing ocean and satellite data sources to produce high-quality ocean analytics and forecasts for a wide array of potential users, from recreational fishers to the oil and gas industry (we’re unclear how this one fosters climate resilience 🙄).
- Osazda Energy — Osazda is adding carbon nanotubes to solar cells’ silver electrode paste, increasing durability in both terrestrial and space-based applications. Micro fractures decrease efficiency in cells, but nanotubes can maintain conductivity across gaps >50 µm.
- VegaMX — another startup leveraging data fusion, Vega is battling wildfires with SAR and hyperspectral satellite data, providing pre-, mid-, and post-fire support to communities and fire fighting organizations.
- Precursor — Using an array of custom terrestrial and third-party on-orbit sensors to monitor the Earth’s magnetic field, Precursor has had 95%+ accuracy across 50 events forecasting earthquakes’ location and occurrence days to weeks in advance, and at the same time can provide high-detail magnetospheric space weather intelligence.
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¶News in brief. Loft Orbital raised $140 million for their hosted-payload satellites, Ursa Major raised $85 million for their yet-to-reach-orbit liquid oxygen and kerosene engines, ICEYE raised $25 million from Seraphim for their SAR satellites, and Astranis announced a $90M deal to provide broadband capacity to Peru using their upcoming MicroGEO sat in 2023 (their first will launch next year to serve Alaska and just passed thermal vacuum testing) ● Boeing is abandoning the Starliner test vehicle that had valve issues postpone its launch last summer; for the (now) May 2022 OFT-2 mission, they will move up a Starliner vehicle originally scheduled for a later crewed mission ● Chinese company Galactic Energy is now the first private Chinese company to reach orbit twice, with their four-stage Ceres-1 solid rocket delivering five satellites to SSO ● Rocket Lab was busy acquiring space solar company SolAero for $80m and launching their sixth and final mission of 2021, ‘A Data with Destiny,’ which launched two BlackSky Gen-2 satellites ● Yusaku Maezawa arrived at the ISS ● France announced a plan for ArianeGroup to develop a small, reusable rocket called Maïa by 2026 which could deliver 1 ton to LEO ● Mexico became the 14th country to sign the Artemis Accords ● IXPE launched successfully on its Falcon 9 ● Planet went public via SPAC and (unrelatedly) Tomorrow.io announced plans for their own SPAC valued at $1.2B post-acquisition ● China’s 400th launch of a Long March rocket (and 49th for 2021) lifted a pair of classified Shijian signal intelligence satellites—China’s first LM launch was in 1970, but the cadence has increased so much that their 300th happened just 3.5 years ago ● Alan Shepard’s daughter, the host of “Good Morning America", and four paying customers took a suborbital ride in New Shepard’s third flight ● The FAA is ending their Commercial Space Astronaut Wings program ● Russia launched two Ekspress domestic communications satellites on a heavy-lift Proton-M ● NASA announced their next class of astronauts ● The JWST is fueled and scheduled to launch next week. 🤞 |
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 | XKCD #2550 - “Each one contains a chocolate shaped like a famous spacecraft and, for the later numbers, a pamphlet on managing anxiety.” |
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