The Orbital Index

Starship explodes on the test stand. Starship upper stage Ship 36 exploded (“experienced a major anomaly”) on the test stand ahead of a second static-fire test (slow motion video). The test site, Massey’s, is separated from SpaceX’s launch facility at Starbase and the area was cleared for the test, with no injuries reported in the incident. Initial analysis suggested that a nitrogen composite overwrap pressure vessel (COPV) in Ship’s payload bay failed, ripping through the header tank and causing an explosion, followed by a second explosion of the propellant in the main tanks. Damage to the surrounding area was significant (video). This is another setback for the Starship program—Ship 36 would’ve been the upper stage for Flight 10, previously planned for as soon as June 29.

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IMAP will map the heliosphere. NASA’s Interstellar Mapping and Acceleration Probe (IMAP) is a 900 kg, 2.4 m-diameter heliophysics observatory slated for a Falcon 9 launch from Cape Canaveral NET September 2025. After launch, it will make its way to the Sun–Earth L1 point ~1.5 million km sunward of Earth. Upon arrival, IMAP will spin at 4 rpm for uninterrupted sky coverage. Its ten-instrument payload has been assembled to image and sample the magnetic, plasma-inflated shield that makes up our solar system’s heliosphere, as well as the particles that pass through from the outside. Three energetic-neutral-atom (ENA) imagers (IMAP-Lo, -Hi, and -Ultra; 0.1–300 keV) will produce full-sky, multi-energy ENA maps that can be combined tomographically to infer the three-dimensional structure of the interface between the supersonic solar wind and the local interstellar medium (ISM). Four particle spectrometers (SWE, SWAPI, CoDICE, HIT) will sweep up electrons and ions, moving at speeds ranging from ~100 km/s to relativistic. In addition to expanding heliospheric science, this will potentially supply ~30-minute radiation-storm warning for satellites and crews near Earth. Other instruments include a boom-mounted dual fluxgate magnetometer (MAG) that will chart microtesla-scale field dynamics; GLOWS, which will trace solar-wind structure via Lyman-α ultraviolet photons; and IDEX, which will chemically fingerprint micron-sized interstellar dust grains, revealing the galactic environments that birthed them. Together, the suite aims to answer three questions: What is the elemental and isotopic makeup of nearby ISM gas and dust? How does the solar wind-ISM interaction sculpt the heliosphere? And, by what mechanisms are solar and cosmic particles accelerated to near-light speeds? Led by Princeton University, with spacecraft integration at Johns Hopkins (time-lapse video), IMAP recently cleared thermal-vacuum testing at Marshall and is in the midst of final launch processing in Florida. Over its planned five-year mission, IMAP will update heliosphere maps every six months while producing continuous in-situ data, improving understanding of our solar system’s protective bubble as well as refining space-weather models.

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• Early in the history of Earth’s atmosphere, a reducing environment rich in hydrogen and methane facilitated chemical reactions with UV light coming from a young Sun. These reactions produced prebiotic molecules like formaldehyde and hydrogen cyanide. The resulting material may have covered our primordial oceans with a layer of organic matter several hundred meters thick (paper), which could have shielded deeper molecules from the otherwise damaging UV light and allowed the formation of progressively more complex prebiotic materials critical to life.
• Maybe the Milky Way and Andromeda won’t collide after all? New simulations suggest only a 50% chance of our galaxy colliding with our nearest neighbor in the next 10 billion years, and almost certainly not during the next 5 billion. Even if the two galaxies do collide, it’s unlikely any stars would—space is very big.
• A coronal mass ejection in March 2024 reached Mars three days later, triggering a planet‑wide solar‑energetic‑particle (SEP) aurora. Perseverance captured the first visible‑light image of an aurora on another planet during the event, while MAVEN’s SEP detector measured the incoming particles (paper); MAVEN had previously discovered ultraviolet SEP auroras analytically in 2014. Unlike on Earth, where our magnetic field entrains particles near the poles, exciting atmospheric oxygen and nitrogen and causing them to glow, Mars’s weak magnetic field allows solar particles to pass through, where they interact with the atmosphere to create a diffuse green glow across the night sky.
• White dwarfs, the slowly cooling remnants of main-sequence stars, are usually assumed to be unlikely places to find life, as they are cold, and their preceding fiery red giant phases probably didn’t leave much in the way of planets behind. However, if any planets did survive their star’s death throes, life might still be able to survive or evolve on them. The habitable zone of a white dwarf system is very close to its cold(ish) host star, meaning any planets that end up in the zone would likely be tidally locked. Recent simulations using 3D climate models of water-covered exoplanets around white dwarfs found that their rapid orbits and rotations result in limited cloud cover and more retained heat, possibly sufficient to allow habitation (while their stars slowly cool over billions of years).

• We didn’t write much about Honda’s surprise, successful test of a VTOL rocket last week, but it’s worth pointing out that their hopper demo was impressive. It’s “the first prototype rocket outside of the United States and China to complete a flight of this kind, demonstrating vertical takeoff and vertical landing technology” and it landed less than a meter from its target. Honda hasn’t decided yet if this will proceed to the development of a full orbital vehicle. Here’s a video of the test.
• NASA held its 25th Student Launch Competition, where 50+ teams built and launched rockets up to 1,800 m, with James Madison University as the overall winner.
• NASA’s Lunar Reconnaissance Orbiter captured photos of the site where ispace’s Resilience lunar lander experienced a hard landing (c.f. Issue 322).
• Vast released a VR experience to explore their upcoming Haven-1 space station.
• A time-lapse of Chinese satellites Shijian-21 and Shijian-25 making a close approach, or possibly docking, in GEO. Shijian-25 (launched this year) is intended to demonstrate on-orbit satellite refueling and servicing, while Shijian-21 was launched in 2021 to demonstrate moving a defunct GEO satellite into a graveyard orbit.
• The Global Burst Detection system, hosted by GPS satellites, monitors for nuclear explosions. Sensors on geostationary satellites serve similar functions, including monitoring for x-ray, gamma-ray, particle, and EMP events.
• Atlas of Space