Issue No. 64


The Orbital Index

Issue No. 64 | May 12, 2020

🚀 🌍 🛰

China’s Tianwen-1 Mars mission is almost ready. Now officially named—meaning ‘questions to heaven’—, China’s first dedicated Mars orbiter and rover are lined up for launch in July (pictures), along with NASA’s Mars 2020 Perseverance rover and the UAE’s Hope Mars Mission. Primarily due to parachute challenges, ExoMars has been delayed until 2022. Tianwen-1’s orbiter has a high resolution, 0.5m per pixel camera comparable to HiRise, as well as radar, magnetometers, and spectrometers (likely calibrated to detect methane). The mission will be controlled using Asia’s largest steerable radio telescope—built specifically to enable this and other deep space missions. The rover weighs in at 240 kg (for comparison, their Yutu lunar rover is 140 kg, while NASA’s upcoming Perseverance is 1,025 kg), and will carry ground-penetrating radar (paper) to look for subsurface water, multispectral cameras, a Laser-Induced Breakdown Spectroscopy instrument, and other science payloads. It is targeting an early 2021 rocket-propelled landing in Utopia Planitia, the same region where Viking 2 landed, and that NASA suggested could hold buried water ice equivalent in volume to Lake Superior. So far, only NASA has successfully operated a rover on Mars. The Tianwen name is intended to be the moniker for all future Chinese interplanetary missions. Related: Along with the Chinese space station and lunar sample return mission, China is also exploring an asteroid sample return mission, a Voyager-like Interstellar Heliosphere Probe, a Mars sample return mission, and other potential planetary missions.


And let’s talk about that Mars 2020 helicopter. Inside a debris shield attached to the belly of the Perseverance rover is a twin-rotor, solar-powered helicopter, now named Ingenuity (by a high school student from Alabama, one of 28,000 submissions). Once a suitable location is found in Jezero Crater—approximately 60-90 Martian days after landing—the helicopter will drop off the rover and take flight for a few minutes at a time (JPL animation of how it’ll fly), becoming the first aircraft on another celestial body. Carrying no science instruments, the 2 kg rotorcraft is an engineering test for future, larger, Martian aerial explorers. It uses counter-rotating coaxial rotors about 1.1 m in diameter to handle Mars’ atmospheric density that is only 1-2% that of Earth’s, heaters to survive the -140° C night, a downward-pointing camera for navigation, a Snapdragon processor running Linux, a radiation-tolerant FPGA, two flight controller MCUs (for redundancy), and redundant 900 MHz Zigbee links that can send 250 kbit/s over distances of up to 1 km. Due to Mars’ inconsistent magnetic field, instead of a compass, the drone will use a solar tracker camera, the downward-facing camera for visual navigation (pdf), and inertial navigation. See the Mars Helicopter Technology Demonstrator (pdf) for more technical details.


Space-to-Earth power beaming experiments. An Atlas V launch carrying the U.S. military’s reusable X-37B space plane is planned for May 16—this is the X-37B’s sixth mission (the first with a service module attached) and will carry Air Force & NASA experiments and a U.S. Naval Research Laboratory (NRL) beamed microwave power experiment (aka far-field wireless power transmission). Beamed power has been a recurring theme for the NRL recently, with a laser power transmission demonstration last fall—the 2 kW laser delivered power to a receiver using wavelength tuned photovoltaic cells to convert the photonic energy into 400W of  DC power. Astronaut Jessica Meir recently shared a related demonstration sponsored by the NRL that showed a simple LED/diode circuit receiving energy from the station’s WiFi access point. The DoE has an explainer page on space-to-ground PV power transmission, complete with cute satellite animations. Meanwhile, Casey Handmer has a strongly held, yet reasonable skeptic’s view of microwave-based transmission given current technology.

News in brief. SpaceX's Starship SN4 test-fired a single Raptor engine twice and passed high-pressure testing (7.5 bar) in the lead up to a likely 150 m hop—three engines will eventually be used on higher altitude tests, and six on the orbital version; for the first time, a Fast Radio Burst has been detected from (probably) within the Milky Way—if it repeats, we may be able to figure out what causes these energetic radio flashes; China’s next-gen crew capsule returned to Earth after functioning as planned (unfortunately, its secondary cargo capsule with an inflatable heat shield did not) and its core stage became the largest unguided reentry since 1991; Yevgeny Mikrin, the head of Russian human spaceflight passed away at 65 from COVID-19; the Trump administration is working on an international agreement for lunar mining called the Artemis Accords; Airbus and Xenesis signed a contract for a payload slot on the recently attached Bartolomeo ISS platform, for hosting a demonstration 10+ Gbps optical communications terminal; and, Virgin Orbit’s first orbital launch could happen later this month over the ocean southwest of Los Angeles (they also just signed a Space Act Agreement with NASA to explore the development of supersonic vehicles).

This week we’re experimentally adding a jobs section to the newsletter. Please let us know what you think, good or bad. And if you know of an open position, especially at your company, send us a note!


A photo taken by Opportunity on Mars’ plains of Meridiani in May 2005. You should check out the high-res downloadable wallpapers.


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