¶Chang’e-5. Originally scheduled for 2017, but delayed by the (unrelated) launch failure of its heavy-lift Long March 5 vehicle, China’s lunar sample return mission is launching next week. Chang’e-5 will collect and return about 2 kg of samples, the first lunar samples since the 1970s. Chang’e-5 consists of an ambitious four spacecraft fleet—a propulsion module to bring the vehicles into lunar orbit, a lander to collect samples, an ascent vehicle to carry the samples into orbit, and a return module that will receive the samples via orbital rendezvous and bring them to Earth. The lander is targeting the Mons Rümker formation on the near side of the Moon to collect relatively young (~1.21 billion years old) volcanic samples during one lunar daytime (14 Earth days—it can’t stay longer since it doesn’t have radioisotope heater units like Chang’e-4). To bleed off speed, the return vehicle will use a ‘skip reentry’ in which it bounces off the upper atmosphere once, as tested in the 2014 Chang’e-5-T1 test mission. It’s sibling, Chang’e-6, was built at the same time and will either serve as a backup if Chang’e-5 fails, or be repurposed for a south pole landing in a couple of years. Related: China’s proposed architecture for future crewed Moon landings. |
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 | Chang’e-5 during testing. |
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¶“All for one. Crew-1 for all.” After a month-long delay, due to the now-resolved issue with new Merlin engines’ potential for a lacquer-clogged relief valve, NASA certified Crew Dragon and Falcon 9 for routine crewed flights to the ISS and subsequently launched Crew-1 last Sunday. After a nominal liftoff and 27-hour transit to the station, with only a few minor hiccups along the way, the four astronauts (Victor Glover, Soichi Noguchi, Shannon Walker, and Michael Hopkins) joined the existing crew of three on Monday evening 📺. Victor Glover became the first Black astronaut to crew the station. In another first, the FAA licensed this crewed flight for NASA, much like it does commercial airline flights—perhaps this sets us on a path to commercial crewed launches becoming a common occurrence. Crew-2 is scheduled to launch on the same Falcon 9 booster as Crew-1 while also reusing the Crew Dragon capsule from Demo-2. It’s currently scheduled for NET 30 March 2021. Crew-3 will continue the 6-month cadence, launching next fall. |
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¶Papers- It looks likely that a supernova exploded near our solar system around 2.5 million years ago (paper). Evidence comes from elevated concentrations of two metal isotopes known to be formed in supernovae: 53Mn and 60Fe. 60Fe has a half-life of 2.6 million years, so we know that it cannot be too old. And, while the iron isotope can also be created by some types of stars, the manganese isotope can not—finding them together is strong evidence for a recent and nearby supernova. This supernova likely formed the local bubble, and its particles could have triggered cloud formation on Earth, and thus maybe even the Pleistocene epoch of ice ages, a megafauna extinction, and (very speculatively) an acceleration of our ancestors’ move to bipedalism.
- Scott Manley covers 📺 the GW190521 black hole merger event (as seen by gravitational wave telescopes) which released enormous amounts of energy—9 solar masses worth of mass were converted directly into gravitational energy in a fraction of a second—and demonstrates a new class of intermediate-mass black hole (paper).
- Speaking of gravitational wave telescopes, think building detectors kilometers long that are sensitive enough to detect a ripple in spacetime 10,000 times smaller than a proton is hard? Imagine building one on the Moon (paper).
- The gravitational waves mentioned above all have frequencies measured in hertz. However, 12 years of pulsar timing data released by NANOGrav (paper) may show evidence of a long-period (nanohertz!) gravitational wave background, prompting people to claim evidence of cosmic strings, dark matter radiation, and more.
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| ¶News in brief. Virgin Galactic’s VSS Unity test flight should happen this week—it will carry payloads from NASA’s Flight Opportunities Program; the US Senate appropriations bill does not meet NASA’s budget request for a 2024 Artemis landing; an Indian PSLV vehicle deployed 10 satellites, including India’s EOS 1 radar imaging satellite, four of Spire’s Lemur-2 CubeSats, and four of Kleos Space’s radio-frequency triangulation CubeSats—the latter company just raised $13.8 million to continue building their radio mapping constellation; a second cable failed at Arecibo, causing more damage; Starship SN8 melted the internals of one of its Raptor engines during its third static fire test, which resulted in loss of pneumatic control that led to a header tank not venting—the vehicle was only saved from an over-pressure RUD by a burst disc; Astrobotic received a $5.7M Tipping Point contract from NASA to develop a magnetic resonance-based wireless charging system for small lunar rovers (we’re hoping it fairs better than Apple’s AirPower); NASA and ESA’s Mars Sample Return mission reached another important milestone with NASA’s independent review approving of its technical feasibility and recommending that the program proceed; ESA signed a trio of Copernicus contracts worth 1.3 billion euros—meanwhile, the in-orbit Copernicus Sentinel-5P satellite can now spot the nitrogen dioxide plumes from individual ships from space; an Atlas V successfully launched NROL-101; and, it looks like Earth has indeed re-captured a 1960s era rocket booster. |
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¶Etc.- To Moon or moon? We have chosen ‘Moon’ (but we’ll still probably slip up).
- Casey Handmer makes the case for affordable space stations. (Of which the ISS isn’t— he calculates that, all in, research hours on the ISS have cost at least $2 million/hour.)
- With more frequent launches, we should consider their possible impact in terms of air pollution and greenhouse gas emissions. Tim Dodd has a good video placing emissions in the context of other emitters. 📺
- Scott Manley reviews the worst looking rockets of all time. 📺
- Another video of OSIRIS-REx’s TAG operation, covering a 3-hour period. 📺
- A Google Earth timelapse, showing changes to our planet from 1984 through 2018 including glacial retreat, meandering rivers, reforestation, urban growth, and shrinking lakes.
- In 1977 NASA released a design study for creating 10,000-person space settlements orbiting Lagrange point 5 (L5). Much of it is relevant 40+ years later. One change: rocket launch environmental impact was considered in terms of ozone depletion (due to the Space Shuttle’s motors producing free chlorine during launch).
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