Issue No. 51

The Orbital Index

Issue No. 51 | Feb 13, 2020

🚀 🌍 🛰

Solar Orbiter is on its way. On Sunday night, an Atlas V launched ESA and NASA’s Solar Orbiter onto its journey to study how the Sun’s polar regions affect the Sun’s 11-year cycle and create the heliosphere that surrounds our solar system, protecting us from (some) cosmic rays. In order to image the Sun’s poles, the mission’s orbital inclination will be slowly increased through gravity assists from Earth and Venus, eventually reaching 33° above the ecliptic in 2029. (The only other mission that could have seen the Sun’s poles was Ulysses in 1990, which reached an impressive 80.2° inclination by flinging itself past Jupiter, but was much further away and did not carry a camera.) Solar Orbiter requires an advanced 150 kg heat shield to withstand temperatures of up to 520° C—interestingly, the shield's outer layer of titanium foil is coated with SolarBlack, a material made of calcium phosphate from charred animal bones. Ten onboard sensors will peer through peepholes that close when the instruments get too hot. The mission’s solar arrays are based on those used on the BepiColombo Mercury orbiter and can rotate longitudinally to avoid overheating. Solar Orbiter will approach within the orbital distance of Mercury, and then work in tandem with the Parker Solar Probe, which gets 7x closer to the Sun (~9.5 solar radii), but cannot see the poles and cannot take direct images because… its camera would melt. Related: ESA’s next Sun-focused mission will be a pair of satellites that will fly in precise formation, one shadowing the other so that it can image the Sun’s corona.

Commercial Crew update. Last week NASA released additional information on the glitchy Starliner OFT mission—but has not yet committed to any delay, or decision, regarding a re-flight of the mission. Information released online and via a Friday afternoon press teleconference, contained more details on three anomalies that occurred during the OFT mission, including a previously undisclosed issue. The most discussed error up until this announcement was the mission clock being misset, which caused Starliner to station keep, depleting its fuel to a level where an ISS approach became too risky. This Mission Elapsed Time had been erroneously updated from the Atlas V's onboard clock 11 hours prior to launch. The second anomaly stemmed from command & control dropouts due to geographic areas of high noise (close to common cell tower frequencies) interfering with ground-to-space communications. The last, previously undisclosed, issue was an error in the software-defined valve mapping for thrusters on Starliner. This mapping was corrected in-flight 3 hours before reentry—without the fix, incorrect thruster firing could have led to a collision with the service module during separation, potentially resulting in a “catastrophic spacecraft failure. NASA called into question Boeing's software QA and certification process and may require a full re-verification of Starliner's software systems. The agency’s investigation wraps up around the end of the month, at which time we’ll likely know if a second OFT mission is required. We assume that re-verification and re-flight would almost certainly push Starliner's first crewed mission to the end of this year or into 2021. NASA will also conduct an organizational safety assessment of Boeing related to its software testing and certification process—the agency required a safety assessment of SpaceX and Boeing after Elon Musk was interviewed by Joe Rogan, but subsequently deferred Boeing’s. Meanwhile, SpaceX’s Crew Dragon is progressing towards the crewed Demo Mission 2 (DM-2). NASA administrators have confirmed a (very) tentative May 7th launch date pending ISS crew requirements and final mission length, with the DM-2 Dragon capsule departing Hawthorne for Florida this week. Crew Dragon still has several todos before launch: additional parachute testing, some component material changes, and a boatload of paperwork.

Fast radio bursts. Fast radio bursts (FRBs) are millisecond-long broadband radio pulses of unknown, high-energy, extragalactic origin. Radio astronomers have seen many FRBs, usually only once, but a few seem to repeat. Possible sources range from merging black holes or neutron stars, flaring magnetars, Blitzars, ...or, as usual, aliens. Whatever their source, it generates as much energy in a millisecond as the Sun does in 80 years. A new Nature paper pinpointed the source of a repeating FRB as something in a star-forming arm of a nearby Milky-Way-like galaxy, allowing for optical study, and hopefully a future understanding of its environment and at least one origin of FRBs. Another paper suggests that this particular FRB may be specifically coming from a binary star system containing both a massive star and a neutron star (paper).

News in brief. Christina Koch returned from the ISS after 328 days in space, the longest female spaceflight (mission photos) to date—the longest human spaceflight remains cosmonaut Valery Polyakov who spent 438 days on Mir back in 1994-1995; Japan launched a spy satellite; SpaceX is considering spinning Starlink off as a public company, allowing investors and employees to realize gains while keeping the core company private; CHEOPS saw first light; NASA signed a $142 million USD contract with Maxar to demonstrate in-space antennae assembly with their SPIDER robotic arm—the robotic payload will ride on the NASA’s Restore-L spacecraft that is going to rendezvous with and refuel Landsat-7; an Iranian Simorgh (“Phoenix” in Farsi) orbital launch failed, their 3rd consecutive failure for this launch vehicle; and, a Cygnus craft left the ISS and deployed 14 CubeSats.

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