(Via Recode.net) SpaceX is hitting a number of milestones this weekend. On Friday, Elon Musk’s space transportation company launched and landed a used rocket for the second time in its history — a sign that the company could be nearing its goal to cut the costs of space travel.

On Sunday, the company expects to launch yet another rocket. It’ll be the first time SpaceX has attempted to launch two rockets within the span of 48 hours.

It wasn’t exactly intentional. The company pushed back the launch of its reused Falcon 9 from last weekend to this to give its crew time to replace a valve. But the double header, if successful, is a significant step toward the company’s goal of shooting rockets every two to three weeks.

SpaceX president Gwynne Shotwell told Reuters in February that she hoped the company would get to a point where it was launching rockets at that pace.

Tomorrow’s launch will position a second batch of Iridium satellites into space using an entirely new Falcon 9 rocket. The rocket used for the first batch, which was launched in January, was the one the company launched again on Friday.

This will be the company’s seventh launch in 2017.

Of course, this is all in an effort to eventually go to Mars. Musk, who wants to eventually help colonize the planet, said he expects to send his first robotic mission to Mars in 2020. Four years after that, the famously ambitious executive predicted SpaceX will send its first manned mission Mars.

You can watch the launch tomorrow at Spacex.com/webcast and we’ll update this post with video when it’s available.