¶Starship takes a step toward orbit. On Monday, the FAA released final findings on the Programmatic Environmental Assessment (PEA) of the launch impact of (primarily orbital) Starship activity at Boca Chica, resulting in a Finding Of No Significant Impact (FONSI) on the surrounding environment (pdf). While it’s somewhat hard to imagine that the largest rocket in history will not significantly impact the adjacent state park, public beach, and nearby wildlife refuge, it’s completely unsurprising that a federal agency has provided a way forward for the company tasked with building NASA’s HLS to conduct testing of the launch system that will deliver that vehicle to space. However, a notable development during the PEA process that was newly revealed in the FONSI was the removal by SpaceX of plans for a water desalination plant and a methane purification and liquefaction facility, along with a power plant to run them—this represents a huge reduction to the potential impact of the site. The removal of the methane purification capability is particularly interesting since the FAA’s assessment noted that its removal was made possible by Raptor 2’s (previously unmentioned) ability to run on less refined commercial-grade methane, unlike the OG Raptors. The FAA is requiring SpaceX to complete 75+ impact mitigation measures, although none of them jump out as being particularly onerous or likely to slow down Starship’s first orbital attempt—the most significant might be an initial limit of five launches per year. The next regulatory stop will likely be the FAA’s launch license, which is something SpaceX has slipped up on in the past. |
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¶Astra is still struggling. The fledgling small-lift vehicle startup launched LV0010 from Florida on Sunday afternoon carrying NASA’s TROPICS-1. TROPICS’s six cubesats (four of which are still to launch) will track tropical cyclones using spinning microwave radiometers and study the process and cause of the storms’ often fast intensification. Unfortunately, after a nominal first stage burn, stage separation, and fairing deployment, LV0010’s upper stage shut down a minute early during its 5-minute burn. This left the now-tumbling upper stage and two-cubesat payload well short of orbital velocity, crashing near the West African coast a short time later. Despite the loss of two cubesats, the overall TROPICS mission can still accomplish its scientific goals with the remaining four satellites. This marks Astra’s second failure launching a NASA payload from KSC—and their sixth failure out of eight launches. We hope TROPICS-2, scheduled to launch with two more on June 30th (although that may change in light of the failure), will go off without a hitch. |
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¶LISA continues development. ESA’s under-development LISA mission recently entered Phase B, indicating that no showstoppers have been found and that full tech development can now begin. LISA is a phenomenally ambitious space-based gravitational wave detector consisting of three spacecraft flying in a precise triangular formation with 2.5-million-kilometer-long sides. Passing gravitational waves will generate minute changes in the distances between the craft, which will be measured using laser interferometry. LISA will open a new region of the gravitational wave spectrum to observation. Today’s detectors like LIGO and Virgo can spot gravitational waves with frequencies of 100s of Hertz (millisecond wavelengths at the speed of light), and ongoing pulsar timing array efforts will hopefully spot very long wavelength gravitational waves (years!), but we don’t have anything right now that can spot waves with wavelengths measured in hours. These sorts of gravitational waves are expected to be generated by merging stellar-mass black holes and by neutron stars plunging into supermassive black holes. LISA was preceded by the LISA Pathfinder mission in 2015 which demonstrated the required precise propulsion, inertial sensors, and laser metrology needed for the primary mission. It placed two test masses in nearly perfect gravitational free-fall and then measured their relative positions with laser interferometers to an accuracy of < 0.01 nanometers. Related: Another exciting upcoming ESA mission, Comet Interceptor, was just approved for construction. |
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 | The gravitational wave spectrum, the observatories that can sense it, and the kinds of astrophysical events that populate it. |
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| ¶News in brief. Blue Origin’s NS-21, the company’s fifth crewed flight, sent six on a suborbital up-and-back ● France granted small awards to two small launch companies, HyPrSpace (whose rockets are the Baguette-one and the Orbital-Baguette…) and Sirius Space Services ● France also signed onto the Artemis Accords, becoming the 20th country to do so ● Meanwhile, French startup ION-X raised €3.8M for satellite propulsion ● Ariane 6 has been officially delayed until 2023 (unsurprisingly) ● Indian startup Bellatrix Aerospace raised an $8 million Series A for in-space propulsion systems ● A SpaceX Cargo Dragon launch was delayed due to Draco thruster “elevated vapor readings” when loading hypergolic propellants ● A SpaceX Falcon 9 sent Egypt’s Nilesat toward GEO (video), the first commercial GEO launch this year, as LEO constellations dominate the show ● JWST was struck by a larger than expected micrometeoroid (still less than 0.1 millimeters), damaging one of the mirror segments—but don't worry, it can still image better than mission requirements ● NASA set up a commission to study Unidentified Aerial Phenomena led by astrophysicist and Princeton professor David Spergel—it appears at least partly focused on increasing aircraft safety 🛸 ● Despite much saber rattling, Russia will continue to cooperate on the ISS until at least 2024 (and possibly longer). |
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¶Etc.- JWST has nothing on the McDonald Observatory, whose 2.7 m telescope reflector was shot seven times and then hit by a hammer, but still works fine (h/t Thomas Connor).
- An interactive, illustrated article about space debris.
- Synchronizing clocks on Earth using the muon showers created by cosmic rays when they strike the atmosphere around 15 km overhead. Unlike GPS time signals, muons can penetrate water and rock. Those from one cosmic ray event will cover a few square kilometers of ground, allowing nearby devices to detect a shower and its characteristic signature and then communicate to precisely synchronize their clocks. At about 100 events/hour on every square kilometer of the Earth, clocks can maintain highly accurate synchronization.
- High orbit weather satellites, such as Japan’s Himawari-8 in GEO, sometimes see stars in the background behind Earth. After realizing this, researchers analyzed four years of daily infrared Himawari-8 images that caught Betelgeuse in the background (paper) and found that in 2019 the giant star’s temperature dropped 140° C and that dust seemed to obscure the view, pointing to dual causes for the star's infamous dimming event.
- After 15 months on Mars, Perseverance finally begins searching the sedimentary rocks of Jezero Crater’s river delta for signs of life.
- Last week we mentioned that material from Ryugu contains a lot of organic matter. The new headline is that it contains “more than 20 types of amino acids” (paper, paper). We’ve known for a while that amino acids can form in space (and we detected them in 2001 in chondritic meteorite material found on Earth), but this is the first direct detection in samples collected in-situ.
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| On April 9, Juno completed its 41st close flyby of Jupiter with JunoCam watching. Citizen scientist Andrea Luck turned the raw data into this stunning animation. |  |
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