Issue No. 6

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The Orbital Index

Issue No. 6 | Apr 2, 2019

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India tested an ASAT missile, creating a cloud of space debris. Like the US, China (quite irresponsibly), and Russia, India has now demonstrated a kinetic anti-satellite weapon (ASAT). India tested at a fairly low altitude, which reduces the duration that debris typically remain aloft, but nonetheless, fragments can be thrown into higher orbits where they can linger and threaten other satellites and the ISS. At closing velocities around 10 km/s, the kinetic energy of even an untrackable chip of paint has the destructive power of an equivalent mass of stationary TNT. Despite alarm and consideration of a boycott of India’s launch services, it’s unclear if there will be any accountability for this test (an Indian PSLV launch proceeded as planned on Monday bearing 28 commercial smallsats from 4 countries). The space environment, like the plastic content of our oceans and the CO2 ratio of our air, is a commons that humans haven’t typically been very good at managing.

DARPA is hoping to develop a nuclear thermal rocket. The Pentagon’s 2020 budget request includes $10 million to begin development of ROAR (Reactor On A Rocket), a nuclear thermal propulsion (NTP) engine. The money would be used to develop additive manufacturing techniques for creating system parts in orbit. However, much more investment will be required to build a working engine. NTP rockets vaporize liquid hydrogen using heat from an onboard nuclear reactor and could have a specific impulse (Isp) of 850-1000 sec. That is about twice the fuel efficiency of a traditional rocket engine which generates thrust from the stored chemical energy released through burning a propellant with an oxidizer. DARPA’s project may be related to increased investment from NASA into NTP.

Chinese commercial companies are still seeking orbit. OneSpace Tech’s OS-M1 solid-fuel four-stage rocket failed to launch a small imaging test satellite last week. Founded in 2015, OneSpace Tech is a private Chinese company (albeit with investment from the Chongqing government) whose goal is to provide frequent launches for small satellites. iSpace will be the next commercial Chinese company to attempt an orbital launch with their Hyperbola-1 rocket as soon as next month.

The US announced (again) that it will go to the moon (again). The announcement and its rigid five-year timeline were widely covered. Skeptical opinions (here, here, and here) place the announcement in historical context, question the motive, and call attention to the lack of any real funding for accomplishing the goal. The announcement dovetailed with uncertainty around SLS due to more delays and proposed budget cuts.


A graph of space debris over time, highlighting Chinese Fengyun ASAT testing and the Iridium-Cosmos collision.

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