US addresses space to Earth threats, and highlights what Dmitri Stefanovich referenced this morning: the greatest threat was nuclear weapons in space, which is why the Soviets and US agreed to prohibit them in art IV #OST. Therefore, US does not consider space-based weapons to be a serious threat today. Refers to the excellent work of @LauraEGrego and @bleddb to underscore why space based missile defence is not feasible, and reiterates US is not, never has, developed this non-starter

UK asks what other "low hanging fruits" there might be. especially for TCBMs. #SpaceThreatsOEWG. Dmitri Stefanovich says: total clarity about intended purpose of activities and use of specific capabilities. This is the same in other domains. Can be de-escalating and preventive Unilateral commitments not to test direct-ascent ASATs are good, says Dmitri, but what will happen if these get challenged? If a capability is being developed that looks like an ASAT but is justified as something else? Will the commitments work?

Dmitri Stefanovich agrees partially with @bleddb that arms race is a challenge as key concept. Nuclear arms race is about action- reaction, which we don't see in space in terms of exact replication of weapons. But still see counter space spending increasing Expense of action reaction includes not only money, but also political capital. Arms race in space may not be the real issue, need to think about how and in what investments are made

Next up @bleddb from @uniofleicester #spacethreatsOEWG Is there a potential for non-weaponised mil space systems to be a source of tension or conflict? ASATs are worthless if there is no satellite that is useful to target. The ASAT is the source of tension, not the satellite

The amazing @LauraEGrego now speaking #spacethreatsOEWG on behalf of the Union of Concerned Scientists. Space based weapons that target Earth directly are easy to identify, and right now only hypothetical. Therefore not the greatest threat, and shouldn't be the focus of the #spacethreatsOEWG

Good morning, #SpaceThreatsOEWG we are taking about space to Earth threats today. I can't promise a thread as comprehensive as @JessLuella_West but I'll try! First up Dmitri Stefanovic, Russian International Affairs Council. The concept of "ultimate high ground" comes from the notion of space to Earth threats. It's the reason why nuclear weapons at prohibited in space under the OST.