On Sunday, Elon Musk's rocket company, SpaceX, failed to land its rocket on an autonomous barge in the Pacific Ocean after successfully delivering a payload to space. This follows the successful landing of its Falcon 9 in December. But Musk is confident about the company's ability to land rockets in 2016, predicting a 70% success rate for the year.

Before tipping and then exploding, first stage Falcon 9 approaches center of landing droneship after Sunday launch. Image source: SpaceX.

It's still "experimental"
For now, SpaceX still refers to its landing attempts as "experimental." And the company's current success rate mirrors this terminology. Of the four SpaceX attempts to land Falcon 9, three have failed. The latter were at sea and the one success was on land.

SpaceX was quick to offer an explanation for Sunday's failed attempt, noting that the Falcon 9 actually did land on the droneship, but the lockout collet didn't latch on one of the legs, causing it to tip and then explode. 

While waves were reportedly 12 to 15 feet at the landing location, which could have helped the Falcon 9 tip, Musk admitted the same scenario would have likely unfolded on land.

Addressing confusion in the media about why the company can't try to land on solid ground with every launch, Musk emphasized that it has nothing to do with fuel costs. Instead, it's simply not always physically possible for the Falcon 9 to return to the launch site, he explained. Specifically, missions that require speeds of about 6,000 km/h at stage separation will not be able to make it back to land.

"With a ship, no need to zero out lateral velocity, so can stage at up to ~9000 km/h," Musk said on Twitter. 

But landing at sea is more difficult than on land, Musk admitted on Twitter: "much smaller target area, that's also translating & rotating."

Better chances of success
Going into SpaceX's January launch, it was clear that the company was up against some key challenges. And they went beyond the fact that SpaceX was returning to a sea landing attempt. For this month's launch, SpaceX used its older Falcon 9 v1.0 rocket. During the successful December launch, it used its Falcon 9 v1.1 Full Thrust, which sports about 30% more power, along with other improvements.

Upgraded Merlin engines on Falcon 9 v1.1. Image source: SpaceX.

The use of the company's latest rocket undoubtedly gives SpaceX a better chance at landing, giving future missions with the improved rocket better odds of success.

A 70% success rate in 2016 would be a huge improvement from those three failed attempts at sea and one success on land so far. And, for 2017, Musk expects the company's success rate for landings to "hopefully" improve to 90%.

The goal behind successfully landing rockets, of course, is for SpaceX to reuse them. Musk says he intends to reuse a Falcon 9 rocket for the first time in 2016.