Short answer: no.
Long answer: at their closest earth and mars are about 54m km apart, at the furthest it's over 400, with an average of around 225m km, so theoretical latency is varies between 4 and 24 minutes.
CockroachDB uses synchronous replication via raft, and that latency would cause problems as would some other setting like our window sizes and their interaction with timeouts.
Deep space aside, I wish the announcement just said that! I came back to HN for insight into the paragraph about "multi-active availability... an evolution in high availability from active-active replication". Marketing... sometimes... I tell you what.
"When replicating across datacenters, it’s recommended to use datacenters on a single continent to ensure performance (inter-continent scenarios will improve in performance soon). Also, to ensure even replication across datacenters, it’s recommended to specify which datacenter each node is in using the --locality flag. If some of your datacenters are much farther apart than others, specifying multiple levels of locality (such as country and region) is recommended."
In short, IIUC, even _planetary_ deployment doesn't come for free (yet). Perhaps I'm just not well-enough versed yet in how people deal with globally-distributed databases, but I'd love to see the docs dig into this a bit more: practical limits of cluster deployment, recommended strategies and tools (if any) to replicate data between clusters, etc.