# The Orbital Index

Issue No. 187 | Sep 28, 2022

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 ¶DART practices Applied Planetology. NASA’s $330M Double Asteroid Redirection Test plowed into Dimorphos, the 160-meter-wide asteroid moon of NEO Didymos (itself only 780 m across), about 11 million kilometers away from Earth. The craft had spent the last 10 months in transit propelled by NASA’s xenon-fueled 4,220s Isp NEXT-C ion thruster (using up to 7.4 kW of solar energy). The 22,530 km/h collision (6.25 km/second) is the first time that humanity has attempted to change the orbit of a solar system body and is a study into future planetary defense options, should we need them. Observing the impact was the Italian Space Agency’s LICIACube and a host of ground and space-based observatories (very cool collision video from the ground-based ATLAS asteroid early warning system), including Hubble and JWST, which will measure the change in Dimorphos’s 11.9-hour orbital period, likely by about 10 minutes, or roughly 1% (more impact videos here and here; you might also want to try this). The spacecraft downlinked one image per second to Earth as it homed in on its target. The result of the impact event depends on the composition of Dimorphos and it’ll be a few days at least before we know any firm results. LICIACube, deployed several weeks back, will slowly beam back its images of the event at roughly one per week (although a few of its initial snaps have already dropped). And, a really detailed analysis will have to wait until 2027 when ESA’s Hera mission (and its two cubesats) arrives to survey the damage and measure the exact weight of the mini-moon.  The final (full) frame from DART pre-boop. Here’s an animation of DART’s dramatic final minutes.  ¶Jobs.Physical Sciences Inc. is hiring a Mechanical Engineer in Andover, MA to develop “custom system solutions in optical sensing and related technologies.”  The Orbital Index is made possible through generous sponsorship by:  ¶LunaGrid could power the lunar south pole. Astrobotic announced intentions to build a lunar polar power service on top of the technology developed through their recent NASA Vertical Solar Array Technology (VSAT) award of$6.2M. Astrobotic VSATs (along with competing VSATs from Honeybee and Lockheed) will extend up to 10 m tall and must be retractable for future relocation. This first generation of VSATs will produce 10 kW, pack onboard electronics for grid operation and charging third-party systems, and aim to capture the near-continuous illumination available just above the surface of the lunar south pole. Astrobotic is starting with NASA’s funding and building a broader vision on top of it, imagining a connected grid of multiple VSATs powering tethered CubeRovers which could bring wireless charging pads to locations accessible by customers who want to survive 14-day-long lunar nights. Astrobotic is hoping the first mobile demonstrator VSAT, aboard their Griffin lander, will launch to the lunar surface in 2026. They further envision a multi-VSAT grid operational in 2028. (Meanwhile, based on a recent SBIR topic, NASA is also in the market for a larger 50kW-class VSAT due to the inefficiencies that would be caused by many smaller arrays shading each other.)
 ¶Rocket Lab’s Venus mission. Rocket Lab and MIT recently published a paper about their upcoming joint mission to Venus, the world’s first private mission beyond cislunar space (ignoring Musk’s Roadster), targeting May 2023. The goal of the mission, beyond getting into the record books and further demonstrating RL’s Photon interplanetary bus (already somewhat proven with CAPSTONE), is to search for habitable conditions and signs of life in Venus’s cloud layer and to measure cloud particle properties to inform the development of future instruments. The spacecraft will perform multiple Oberth-effect-optimized burns at perigee to raise its Earth orbit and a CAPSTONE-like lunar gravity assist with the Photon’s bi-propellant propulsion system (Hyper Curie, which can provide about 3 km/s ΔV). At Venus, a small (~20 kg) probe will be released into the atmosphere where it will spend ~330 seconds descending through the cloud layers at 45-60 km. The probe will communicate direct-to-Earth through an S-band link, sending back data from an autofluorescing nephelometer which will shine a laser onto cloud particles and watch for the fluorescence of complex molecules and reflectance patterns that indicate particle shapes. The authors hint that this could be the first of multiple small missions to Venus.
 The small atmospheric descent probe: a 45-degree half-angle sphere cone ~40 cm in diameter. (It appears to be missing its Kerbal pilot in this rendering.)
 ¶News in brief. Tropical Storm Ian is delaying the Artemis I launch and has forced a rollback to the VAB, despite NASA’s hopes to the contrary (Administrator Nelson now says even a late October launch is unlikely) ● Valery Polyakov died, age 80—at 437 days and 7,075 orbits, the cosmonaut holds the record of the most consecutive time in space while aboard Mir in ‘94/‘95 ● The MIRI instrument on the JWST has encountered unexpected motor resistance while using one of its observation modes—its three other modes are working fine, as are the 14 provided by other instruments ● NASA completed a successful SLS tanking test—some hydrogen leaked, but it was apparently an acceptably small amount ● A Soyuz took astronaut Frank Rubio and cosmonauts Dmitri Petelin and Sergey Prokopyev to the ISS, bringing the number of humans on the ISS to 10 (and the total in space to 13) ● A Delta IV launched from Vandenberg with an NRO spy satellite on board— this is the final Delta IV launch from Vandenberg ● At $3B/year, France is increasing its space spending by 25%—this is in some way related to a 25% funding increase request from ESA to its member states, which would give the umbrella agency roughly$6B per year (for comparison, NASA’s budget was $23B in 2021) ● JWST took its first images and spectra of Mars ● Hotel corporation Hilton will design facilities for Voyager Space Holdings and Lockheed Martin’s Starlab ● SpinLaunch raised a$71M Series B—the company has now raised a total of $150M.  ¶Events.October 1st is International Observe the Moon Night, consider observing the Moon.The NASA Space Apps 2022 hackathon takes place this weekend, October 1-2. There are 22 challenges ranging from app development to space exploration, video production, data visualization, and more.The Reef Starter Challenge for technology ideas that could be developed on the Orbital Reef free-flying space station is accepting submissions through November 4th. Prizes are up to$100K.Submit an app to JetBrains’ Space Marketplace to enter their Space Apps Contest by November 6. Prizes include up to $2,000 and a trip to visit JetBrains in Munich.  ¶Etc.A correction from last week: SpaceX has launched 42 missions this year, not 60. They are on pace to hit 60, but won’t get there for a few more months.Nanoracks’s OMD-1 mission (using a Maxar robotic arm) successfully sliced into a sample of corrosion-resistant steel using a friction milling end-effector, demonstrating a low-debris cutting method. This was meant as a tech demo for a hypothetical mission to repurpose spent upper stages as space stations. Years after Shuttle, NASA rediscovers the perils of liquid hydrogen. “Over its lifetime, due to [the complexity of handling liquid hydrogen], the shuttle on average scrubbed nearly once every launch attempt. Some shuttle flights scrubbed as many as five times before finally lifting off. [...] So why does NASA use liquid hydrogen as a fuel for its rockets if it is so difficult to work with and there are easier-to-handle alternatives such as methane or kerosene? [...] the real answer is that Congress mandated that NASA continue to use space shuttle main engines as part of the SLS rocket program.” Sierra Space’s inflatable LIFE habitat successfully completed its burst pressure test (video).Spaced Ventures, a space-focused equity crowdfunding platform, is petitioning SpaceX to sell$25M of the company’s privately-held equity to users on their platform. With SpaceX’s funding rounds this year totaling $2 billion, any potential crowdfunding sale would simply be a gesture of goodwill for the company, and a marketing coup for Spaced Ventures (who would forego all fees and carried interest on the proposed investment). Watch the Saturn V launch at 500 frames per second, with narration. Real Engineering put together a documentary on SpinLaunch, diving into the materials and technologies necessary for their audacious proposal. The final carbon-fiber tether for SpinLaunch’s full-scale kinetic launch system would be one of the strongest tensile structures on Earth—at full spin, the tip would have to support 100,000,000 kg. Also discussed are the shortcuts possible on their vacuum chamber (more of an “extra high-altitude chamber”), the energy requirements (very manageable), satellite g-hardening (ostensibly not as hard as imagined), and heat and momentum management in the projectile (it will be going so fast that a heavy metal heat sink can absorb the heat generated while helping punch through the lower atmosphere). The company has kept secret their solutions to the fundamental challenges of the exit airlock and release mechanisms, though, if they exist. Impressive engineering all around if they can pull it off. (But with a target launch cost of$2,500/kg, it also seems like Starship could still eat their launch…).
 Neptune in IR. JWST recently took a snap with NIRCam of the traditionally blue-looking Ice Giant. Triton’s huge diffraction spikes come from it being small and bright (due to a surface composed of highly-reflective condensed nitrogen) while methane in the larger Neptune’s atmosphere absorbs these near-infrared wavelengths, making it appear fainter.