Issue No. 111

The Orbital Index

Issue No. 111 | Apr 7, 2021

🚀 🌍 🛰

GOES-T and Weather Sats. GOES-T, NOAA’s latest generation geosynchronous satellite, recently completed vibration, vacuum, and acoustic testing ahead of its December launch. GOES-T packs upgraded traditional weather observation instruments (video intro), including the 16 channel ABI imager (up from 5 channels on the previous generation) with 0.5km - 2km resolution (4x the previous gen). This generation also includes GLM, the first lightning mapping system flown in geostationary orbit, which should increase lead time for severe storm warnings and decrease false positives—lightning mappers, aka optical transient detectors, function by detecting the momentary changes in a single near-infrared band. Here’s a near real-time lightning data visualization from GOES-T’s sister satellite, GOES-16. While NOAA moves toward launching this third of four massive GEO satellites that make up the $10.8 billion GOES-R program, smallsat startups at the other end of the spectrum are filling gaps in weather data, bringing commercial forecasting data availability up to the level of optical and SAR Earth observation data. Care Weather recently launched their first test sat with Rocket Lab (developed in just 3 months), with two more planned soon. Care Weather is focused on fast iteration on its way to bringing measurements of radar-derived ocean winds from twice a day to every hour. In November, NOAA issued its first purchase contracts for radio occultation (RO) data from GeoOptics and Spire. RO measures the Doppler shift of a received signal (usually from a GNSS source like GPS satellites) due to bending in a planet’s atmosphere and uses it to produce high-quality temperature, pressure, and moisture data—RO was used by Mariner to measure the existence of an atmosphere on Mars. NOAA wants these providers to generate 20,000 measurements per day and seems to be particularly interested in the application of this data to hurricane forecasting—a previous RO mission, COSMIC, was able to improve typhoon path prediction by 24%. (Related: A couple of weeks back, NOAA’s decommissioned polar-orbiting NOAA-17 weather satellite broke up into 16 trackable fragments—there is no evidence of a collision, which is consistent with this chart explaining the origins of extant space debris.)


The zodiacal light (aka false dawn) is now thought to be caused by Martian dust.

News in brief. The four crew members of Inspiration4, the “first all-civilian mission to space”, have been announced, and the Crew Dragon for the mission will have a new viewing cupola added; the Crew-1 Dragon capsule performed an autonomous port relocation maneuver to make room for Crew-2 and later CRS-22, a first for a US vehicle at the ISS; a helium composite-overwrapped pressure vessel (COPV) from last week's uncontrolled Falcon 9 upper stage reentry landed on a farm in central Washington state; the Hope orbiter successfully entered its target science orbit around Mars to start studying the planet’s climate and atmosphere; China launched a second Gaofen-12 high-resolution optical imaging satellite into sun-synchronous orbit—it is likely a spy satellite approximately comparable to US Keyhole satellites; and, Ingenuity is sitting on it’s “airfield” on the surface of Mars, having survived the -90°C night, and is waiting for its first flight, possibly as soon as Sunday.


A photo of Mars, taken on March 16th by China’s Tianwen-1 from its highly elliptical parking orbit around the red planet. Landing is now planned for May or June. 

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