¶SBSP updates. Space-based solar power, in which satellites (usually proposed for geosynchronous orbits) collect near-constant sunlight and transmit it to the ground (usually via microwave), has been the dream of space enthusiasts for decades. However, technical hurdles (such as the need to assemble massive structures in space) and high launch costs have kept SBSP perpetually out of reach. More recently, with the growing need for carbon-free baseload power and the prospect of dramatically dropping launch costs, SBSP is receiving renewed interest. There are ambitious programs from both China and Europe. JAXA and the Air Force Research Laboratory both have demonstration missions launching NET 2025. And, South Korea, India, and others are exploring the technology. Even Congress is paying a tiny bit more attention. So, while still nascent, progress is being made and there have been some recent low-TRL announcements: |
|
 | A proposed microwave-based SBSP satellite in geosynchronous orbit, CASSIOPeiA, uses phased arrays and a clever geometric design to avoid any moving parts (pdf). Note: this satellite, as pictured, would be at least 1.6 km across. |
|
The Orbital Index is made possible through generous sponsorship by:
   |
|
¶Starlink V2 Minis achieve magnitude 7. In some encouraging news for astronomy, SpaceX’s latest brightness mitigation techniques, used on Starlink V2 mini satellites, appear to be working well. Once SpaceX’s V2 Minis reached their on-station orbit of 480 km, they entered ‘brightness mitigation mode’ which successfully decreased their apparent magnitude to an average of 7.06 ± 0.1 (paper). Super black paint and dielectric film (available from the company at cost to other satellite makers) have been added, and attitude maneuvers when crossing Earth’s termination line are employed once the satellites reach their on-station altitude. During orbit raising, these satellites often appear brighter than previous generations (per SpaceX guidance)—this is in part due to their >4x surface area (116 sq m) compared to V1.5. The American Astronomical Society, along with NSF’s NOIRLab, has recommended that, to reduce the impact on astronomy and stargazing, constellations should darken their satellites to an apparent magnitude of seven or greater—magnitude seven is the approximate point where objects stop being visible to the naked eye. The LSST team has also suggested that this level of brightness may be more easily removed from scientific observation data. Some V2 Minis have continued orbit raising to 520 km, further decreasing their brightness. Full-size V2 satellites, however, will be even larger than the Minis, creating another hurdle for the Starlink team to overcome. |
|
¶Vulcan’s Centaur V upper stage was too thin-skinned. On March 29th, the Centaur V upper stage of ULA’s nearly-ready-to-launch Vulcan Centaur heavy lift rocket exploded on the test stand when a leak occurred and found an ignition source (video). The company’s prolific CEO, Tory Bruno, has disclosed information about the incident over the last few months via Twitter and shared the latest findings of the root cause investigation last week: the upper portion of the hydrogen tank dome, made out of “super thin, high-performance steel,” failed due to higher-than-expected stress on that portion of the tank’s skin. The top of the dome will need to be upgraded with slightly thicker steel than the rest of the tank to mitigate this failure mode. ULA may be able to retrofit or strengthen existing vehicle hardware, or they may be able to determine that their existing pressure margin is acceptable and fly unmodified hardware, as Tory previously suggested. However, this retrofit/evaluation will likely delay Vulcan’s debut further to the end of the year, along with its launch of Astrobotic’s CLPS mission. (Related: Back in 2018, four heavy launch rockets, including Vulcan Centaur, were scheduled to debut in 2020. Five years later, only SLS has taken its maiden voyage.) |
|
 | An image of the Centaur V “anomaly” that occurred on March 29th. |
|
¶News in brief. Nuview raised $15M for a LIDAR mapping constellation ● China tested a parachute system to guide falling boosters, narrowing the landing area of its Long March 3B booster by 80 percent (it can now land with startling precision on unsuspecting Chinese villages! 😒) ● China also launched 41 satellites on a single rocket (a Long March-2D), a record for the country ● Vast is working with Impulse Space for propulsion on their first commercial station ● The final launch of Europe's Ariane 5 rocket was delayed shortly before launch due to a concern over a possible lack of redundancy in the rocket’s SRB pyrotechnics—no updated launch date has been announced ● Engine manufacturer Ursa Major laid off 27% of its staff ● ESA delivered the European Service Module for Artemis II to NASA, which will provide propulsion, oxygen, thermal control, water, and electrical power to the Orion crew capsule ● Tomorrow.io raised an $87M Series E for their growing weather satellite constellation ● Global Fishing Watch won $60M to use AI and satellite data to help end illegal fishing ● Russia, Pakistan, the UAE, and the Asia-Pacific Space Cooperation Organization (Bangladesh, China, Iran, Mongolia, Pakistan, Peru, and Thailand) have signed agreements to engage in China’s International Lunar Research Station ● Meanwhile, Luxembourg hopes to bridge relations between the space agencies of the US and China ● Rocket Lab launched a first suborbital Electron as a hypersonics platform and also delayed their Venus mission to NET 2025 ● Virgin Orbit sold its remaining assets to Firefly Aerospace for $3.8M ● Virgin Galactic, meanwhile, will soon return to flight for its first fully commercial flight, Galactic-01, with a June 27-30th launch window ● A third iROSA 20 kW solar array was installed on the ISS—and plans for a fourth were announced for 2025 ● PLD Space aborted an attempted launch of their Miura-1 suborbital rocket during ignition at T-0 after postponing the launch from southern Spain several times due to above-limit high-altitude winds (video; still image below). |
|
A composite of 90 images taken by Mars Express, ESA’s first interplanetary mission, which is still functioning 20 years after launch. Valles Marineris is in the center of this true color, 20 m/px image, released to celebrate its second decade in service. |  |
|
|
