Issue No. 8

The Orbital Index

Issue No. 8 | Apr 16, 2019

🚀 🌍 🛰️

We have finally seen a black hole. As has been reported widely, this week saw the much-anticipated release of the first image of a black hole’s silhouette. The image was captured by the Event Horizon Telescope (EHT) using microwave Very Long-Baseline Interferometry, which combines observations from a network of telescopes to obtain resolving power equivalent to an Earth-sized aperture. We’re talking “see a credit card on the surface of the Moon” or “see our solar system from 55 million light-years away” level resolution. The image of galaxy M87’s asymmetric ring matches predictions based on simulations of “strong gravitational lensing of synchrotron emission from a hot plasma orbiting near the black hole event horizon,” showing that the “observed image is consistent with expectations for the shadow of a spinning Kerr black hole as predicted by general relativity.” This compelling empirical support for General Relativity at the extremes of gravitation is likely the most important result. But, that in no way diminishes the technical achievement, with petabytes of data analyzed, measurements synchronized worldwide to the microsecond, and locations of the telescopes known to within a centimeter across the globe. Related: a video of stars, some moving at 3% the speed of light, orbiting the black hole in the center of our Milky Way.

Beresheet crashes into the moon. 😢 SpaceIL lost contact with the lander just 149 m above the moon’s surface after the spacecraft’s inertial measurement unit (IMU) failed at an altitude of 14 km. Final telemetry indicated velocities far too great for any possibility of an intact landing. Plans are already underway for a second attempt by the Israeli non-profit. Beresheet, which joins 123,052 kg of crashed human spacecraft on the surface of the moon, was a competitor for the Google Lunar Xprize and SpaceIL was awarded $1 million for their efforts (the deadline for the full $20m prize passed a year ago). Its primary science mission was to analyze the magnetic field near its intended landing site and was able to record some measurements during descent. Other teams have also continued their work on a lunar soft landing. Hakuto (from Japanese company ispace) is slated for launch in 2020, while Moon Express, who raised an additional $12.5 million in September, hopes to launch their first demo mission on a Rocket Lab Electron rocket in late 2020.

The first commercial launch of the Falcon Heavy was a resounding success with all three booster cores landing successfully. During the live feed, there was a brief cut to several odd-looking frames which turned out to be from a camera inside the LOX tank [video with historical comparison to Apollo in-tank footage]. This feed is used to confirm that firing of cold gas thrusters has resulted in LOX settling at the bottom of the tank before engines are restarted. In addition to the successful landings, SpaceX recovered both fairing halves after they splashed down and has plans to refly them as part of the upcoming launch of their first batch of Starlink Internet satellites in May. It is unclear if they will continue to attempt to catch fairings in the future should this refurbishment process prove successful. Unfortunately, the center core was lost in choppy seas while returning from its landing location 1000 km downrange (the longest downrange landing attempted yet). The center core hardware differs from a standard Falcon 9 booster and wasn’t able to be secured to the drone-ship by the Octagrabber robot, leading to the loss. The side boosters will be reused in June after intensive inspection for the STP-2 mission, a DoD payload consisting of 6 smallsats, 8 cubesats, and 11 other small spacecraft. In other SpaceX news: NASA awarded SpaceX a contract to fly its Double Asteroid Redirection Test (DART) planetary-defense mission (which will smash into "Didymoon," the moon of near-Earth asteroid Didymos—we’ll talk more about this mission in a future issue).

More news in brief. Planet signed a $6.7 million contract with NASA to provide Earth imagery for climate research; Intelsat’s 29e geostationary satellite suffered a seemingly catastrophic fuel leak, as caught in this video taken by the ExoAnalytic telescope network; and Stratolaunch, founded by the late Paul Allen, flew for the first time.

A wide field X-ray image of M87's galactic core containing the black hole 'Pōwehi'
(but still smaller than one of Hubble’s pixels)

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