Musk demands that his workers return to work.

World's richest man sends two memos to SpaceX and Tesla.

The electric car company he leads, to spend more time working.

Tesla employees must spend a minimum of 40 hours per week in the office.

Additionally, the office must be where your full-time colleagues work.

We will assume you have resigned if you don't show up," he said.

Tesla's CEO, Elon Musk, took aim at companies that allow remote work,

Some companies don't allow this, but when did they last ship a great product?" he wrote.

Musk said the more senior you are, the more visible your presence must be.

If I hadn't done that, Tesla would have long ago gone bankrupt," he said.