Issue No. 159

The Orbital Index

Issue No. 159 | Mar 9, 2022

🚀 🌍 🛰

Pioneer 10. Pioneer 10, the only spacecraft heading into interstellar space through the tail of our heliosphere, had its 50th birthday last week. Launched in 1972, it was the first successful mission to traverse the asteroid belt, visit Jupiter, and use the gas giant as a gravitational slingshot. Like all craft bound for truly deep space, it was powered by radioisotope thermoelectric generators (RTGs)—we discussed these and other space-based nuclear power sources back in Issue No. 85. Communications with the craft were lost in 2003 when it was 12 billion kilometers (80 AU) away—5 years after ceding the crown for most distant human-made object to Voyager 1. In addition to Pioneer 10 & 11, Voyagers 1 & 2, and New Horizons, upcoming missions that could also eventually leave the solar system include China’s planned “Interstellar Express” and NASA’s Interstellar Probe. In a short ~90,000 years, Pioneer 10 will pass within 0.75 light-years of HIP 117795 while moving at 291 km/s, the closest stellar flyby for either the Pioneer or Voyager probes in the next few million years (paper). We hope someone notices— although the sensing technology required to notice a 258 kg non-transmitting derelict spacecraft at that distance would be phenomenal. Related: We’ve mentioned Pioneer 10 before in the context of the Pioneer anomaly, a deviation from the projected trajectories of Pioneer 10 and Pioneer 11 due to asymmetric heating from their RTGs which caused non-uniform blackbody radiation—the infrared light, emitted by the thermal generator, had enough momentum itself to change the crafts’ trajectories by ~1 km/h over 10 years.

A photo of Pioneer 10 in February 1972, mounted on its kick stage prior to launch.

The Orbital Index is made possible through generous sponsorship by:


Landsat NeXt. With Landsat 9 launched (cf. Issue No 136) and now generating gorgeous data, NASA’s Goddard Space Flight Center and the USGS can start to focus on Landsat NeXt, the next generation of the longest-running Earth observation program, now 50 years old (just like Pioneer 10). Landsat NeXt will have more than double the hyperspectral bands of Landsat 8 and 9. With a targeted 25 bands and increased spatial resolution, this generation will now be able to perform observation tasks like surface composition mapping, soil quality analysis, ice melt tracking, and chlorophyll detection. Additional water quality bands for inland and coastal areas will enable the identification of sediment plumes, harmful algae blooms, and red tides. Scheduled for 2029, the mission is still in its early stages of planning, with instrument studies currently in progress. One of the main outstanding questions is whether Landsat will continue to be a satellite platform with one or two large satellites or a larger constellation of smallsats that can provide the desired faster revisit times (3-6 days vs Landsat’s current 8-day revisit). A constellation approach would also lower the per-satellite costs and provide better resilience to hardware failures like those experienced by Landsat 6 and 7.

News in brief. Satellite Vu raised $21 million for a 7-satellite thermal imagery constellation Romania and Bahrain signed the Artemis Accords, the 16th and 17th nations to do so Russia refused to perform OneWeb’s 14th launch on Friday unless the UK government divested from the company, a demand which was rejected, basically ending Russia’s commercial launch program—OneWeb suspended all Baikonur launches and now needs to find capacity for six more batches to complete their 648 satellite constellation Meanwhile, yet another Starlink launch, and then another this morning (their tenth launch in 10 weeks), are continuing the rollout of Starlink’s second phase and demonstrating the power of vertical integration Iran claims to have launched their Noor-2 military satellite on a Qased solid rocket German-Russian eROSITA is in safe mode due to sanctions A (probably Chinese) spent rocket body smashed into the Moon’s far side at 2.5 km/s, likely leaving a 20-30 m shallow crater—LRO will keep an eye out for the impact site Maine aerospace startup bluShift Aerospace successfully performed a full-scale test of its hybrid rocket engine fueled by a unique non-toxic, carbon-neutral, bio-derived solid fuel (video) which they “found at their family farm” 🤯  A Chinese Long March 2C delivered six 190 kg broadband test satellites with 40 Gbps throughput for Galaxy Space (but possibly testing a future national broadband megaconstellation) and a remote sensing cubesat Astra said LV0009 will launch soon and shared details on their failed orbital launch—the fairing’s 5 separation mechanisms fired out of order, resulting in off-nominal fairing movement and electrical disconnection, and an unrelated software issue caused the upper stage to tumble Chamath Palihapitiya and Richard Branson are being sued over allegedly covering up flaws in Virgin Galactic's spaceships and then pocketing millions by dumping shares Jiang Jie, Chief Engineer of China’s CALT, noted that China hopes for a crewed lunar mission before 2030 Psyche’s massive solar arrays have been installed on its electric propulsion chassis ahead of a NET August 1st launch.


Psyche’s 75 m2 solar array is likely the largest ever built for a deep space probe. In space near Earth, the solar arrays will generate 21 kW, but at Psyche, they’ll produce only about 2 kW.


  • Voyager 1, itself now more than 40 years post-launch and having flown through interstellar space since 2012, is still contributing to science. Its Plasma Wave System instrument has been sampling the interstellar electron density every 0.03 AU or so over a 10 AU window since 2017 and has been detecting unexpected narrowband plasma oscillations (paper). This detection suggests our models of the interstellar plasma need to be updated. Voyager 1’s RTG is getting weak, though, and contact is expected to be lost some time this decade. Keep on going, buddy!
  • The per-launch cost for the first four annual SLS launches (at least) is now estimated at $4.1 billion. Here’s the breakdown… disposable SLS rocket: $2.2 billion; ground system operations: $568 million; disposable Orion spacecraft: $1 billion; ESA Orion Service Module: $300 million. 🤯 NASA Inspector General Paul Martin called out both NASA and their large contractors for "very poor" performance and “a price tag that strikes us as unsustainable," adding that “the cost-plus contracts that NASA had been using to develop that combined SLS-Orion system worked to the contractors' rather than NASA's advantage.” For one $4.1B SLS launch, you could buy twenty-seven (27) reusable Falcon Heavy launches. NASA does some great work, but managing the SLS program is not where it’s happening.
  • The AFRL and US Space Force revealed plans for their Cislunar Highway Patrol System (CHPS) 🤦 satellite to monitor cislunar space. The satellite is experimental, but with numerous lunar missions under development, the implication is an expansion of the Space Force’s situational awareness capabilities to the Moon and beyond, hopefully providing needed tracking to many parties and clearing up ambiguities… such as whose rocket really just hit the Moon.
  • Relatedly, a bit more has been shared about Steve Wozniak’s new space company, Privateer, which is writing software to “take all of the available data about debris in space — collected from ground radars, and eventually, Privateer's own satellites — and synthesize it into the world's clearest picture of where things are in orbit.” They are planning to launch monitoring sensors on satellites and to measure structural details of debris in addition to position and velocity.
  • We’ve mentioned using cosmic-ray muon tomography to look inside the Great Pyramid of Giza in the past. A new proposal, called the Explore the Great Pyramid mission, would scan with 100x the sensitivity and detect muons from more angles. It would produce a true tomographic map of the entire internal structure, differentiating not just stone and air, but also measuring variations in density. The form factor for the experiment is 8 shipping containers of equipment periodically moved around the pyramid.

Jupiter as seen by Pioneer 11 from 760,000 km away.

© 2020 The Orbital Index. All rights reserved.

Powered by Hydejack v8.4.0