Issue No. 107


The Orbital Index

Issue No. 107 | Mar 10, 2021

🚀 🌍 🛰

Starship Sticks It. Starship SN10 roared up to 10 km and landed in one piece,🥇completing a first successful belly-flop-flip-to-land maneuver—a critical milestone, and something that many were initially skeptical of. Then, bored from sitting on the landing pad for a whole 8 minutes, SN10 casually took a rapid unplanned second flight (glorious slow-motion video). This ‘rapid turnaround’ may have been caused by a small bounce at the end of the landing sequence—if you can imagine a 12-story building bouncing—due to low thrust and malfunctioning landing legs potentially creating a methane or LOX leak. Starship’s landing flip has evolved over its three attempts: this successful landing involved re-lighting all three engines to ensure at least one would work, then down-selecting to one engine for a near-hover before landing. While this is a big step for the program, the fiery after-party may negatively impact SpaceX’s chances of winning the lunar Human Landing System contract—NASA will announce the next phase of contracting for the lander later this spring. SpaceX seemed to take little notice of the explosion and has already rolled SN11 out to the launch pad for cryogenic proof testing followed by a static fire test—the most exuberant fans are predicting its launch as soon as late next week. (Ed.: The question of how a functional Starship might impact future NASA flagship exploration missions has come up in our recent live conversations with Casey Handmer and Nick Parker. In particular, how would drastically increasing the mass limit on these missions reduce their complexity, engineering timelines, and cost? And, what new science can it enable? We’d love to hear about any contingency planning going on at NASA for a future where Starship flights are routine.)


Brown Dwarfs. Not quite a planet, not quite a star, brown dwarfs are “substellar objects” which aren’t massive enough (13-80 Jupiter masses) to fuse hydrogen into helium, but form like stars from gravitationally collapsing regions of gas and dust in molecular clouds. They are also incredibly common, with an estimated 100 billion scattered across our galaxy, predominantly in star-forming stellar clusters. Brown dwarfs are born hot from the gravitational compression of their gases and can fuse deuterium until that limited supply runs out, but then they slowly cool over time. Some recent brown dwarf highlights: a binary brown dwarf system, the first radio-based detection of a brown dwarf (paper), a brown dwarf with its own planet, a survey of our oddly brown-dwarf-rich stellar neighborhood, and data suggesting that brown dwarfs’ high-speed winds create a striped appearance (paper), similar to Jupiter. NASA’s Nancy Grace Roman Space Telescope will likely identify many more of these almost-but-not-quite-stars.

An artist’s conception of a brown dwarf.
(Quick) Papers.

Phobos, as seen by ESA’s Mars Express. Phobos is the darkest moon in the solar system (albedo of 0.071) and is thought to be covered in a meter or more of loose dust. Its orbit is decaying, and in ~50 million years it will pass within Mars’ Roche radius and break apart, forming a ring system or dropping fiery pieces over the Martian surface (or both).

News in brief. NASA awarded a contract for Northrop Grumman to build the tiny, two-stage Mars ascent rocket for the future NASA/ESA Mars sample return mission; NASA also selected Astra to launch their 6 CubeSat TROPICS storm monitoring mission; Perseverance has now dirven a little bit on Mars to test its mobility system, received a software update, and completed other checkout tasks—next up is finding a good place to drop off Ingenuity; Crew-2 is now scheduled for a late April launch, while Starliner’s OFT-2 mission has been delayed again (no new launch date has been released at this time); SpaceX launched 60 more Starlink satellites and safely landed the booster for the eighth time—they’ve now launched 1,143 operational Starlink satellites (with ~60 deorbited) and recently requested FCC approval to mount their terminals on large moving vehicles like aircraft, ships, and RVs; Blue Origin will be funded by NASA to modify New Shepard’s capsule to produce lunar gravity conditions during freefall by rotating at 11 rpm using its reaction control system; Russia and China have signed a deal to collaborate on a Lunar research base; the long-awaited JWST completed final pre-launch functional tests ahead of its scheduled October launch; and, ICEYE released the first SAR images from its newest  SAR satellites which launched in January on Transporter-1.
A SAR image of Wrangell, Alaska (map), captured last month by a new ICEYE SAR satellite.
  • Virgin Orbit is hiring an Advanced Manufacturing Propulsion Engineer. Additive manufacturing experience is a plus, but folks with subtractive-only experience should apply as well.
  • Kubos is hiring a Senior Software Engineer to work on the “development and integration of a hybrid container system that will be used to develop and host applications on multiple platforms in the cloud and on various spacecraft.”
  • Allan McDonald has died. As the director of the Space Shuttle booster program at contractor Morton Thiokol, Allan refused to sign off on the Challenger launch, and when he was overruled and it ended in a historic disaster, he exposed the cover-up.
  • Ingenuity, if it works, will be the first powered, non-rocket-propelled flight on another world. The first flight, though, has got to go to the aerobots released into Venus’s atmosphere by the two Soviet Venera missions in 1985. The 3.5 m helium balloons floated 54 km above the surface in the most active layer of the Venusian clouds, measuring temperature, pressure, wind speed, and aerosol density for over 46 hrs.
  • Casey Handmer published a follow-up to his excellent piece from last week about SLS.
  • Huge sky surveys, like DESI’s 10 trillion pixel one, are a treasure trove of data waiting to be explored. You too can explore DESI’s data online. Maybe you’ll find a new brown dwarf or Einstein ring.
  • While the long-awaited JWST will likely revolutionize astronomy and exoplanet observation, Robert Zubrin presents a case for thinking even larger, while reducing costs. He suggests that we build “Enormous Space Telescopes” (ESTs) using huge reflective membrane disks that are spun and accelerated along its central axis (or electrically charged) to take on parabolic shapes. He proposes a test using a 12U CubeSat with a 1 km tether connected to a lightweight spinning disk of aluminized material. “This little demonstration EST, with a total mass less than 20 kg, including optics that would be positioned along or suspended from the tether at the parabola focal point, would have four times the light gathering capacity of Webb (about thirty times that of Hubble), while costing on the order of 1/1,000th as much.

A beautiful high-resolution picture of Mars’ north pole, taken by Tianwen-1.


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