After four unsuccessful attempts, burgeoning aerospace company SpaceX performed the world’s first upright rocket landing at sea last Friday. Hitting a target about the size of a football field, the team landed the first stage of its Falcon 9 rocket a few minutes after launching it on a mission to resupply the International Space Station. As if the feat wasn’t impressive enough, the landing was a performed despite facing 80 km/hr (50 mi/hr) winds. This is a huge step forward in the quest for reliable and reusable rocketry.
Landing in the ocean sounds super complicated. Why bother doing in the first place?
The main advantages are really based on speed and fuel. Rockets do not follow a straight line into space, they follow a curved path. So in order to bring it back to dry ground, the rocket must come to a complete stop, then turn around before it begins its landing approach. This maneuver uses a lot of fuel. A sea landing allows mission control to align the barge along the flight path. This allows the rocket to follow a more direct route back to Earth, a much more efficient use of fuel.
Why is fuel efficiency so important? Using less fuel in the flight path means more fuel can be used during takeoff, which is necessary for missions with heavy payloads. These missions require faster velocities to get into orbit. Because the flight path for ground landings require the rocket to eventually stop and turn around, the highest velocity that can be achieved before stage separation is around 6000 km/hr (3700 mi/hr). However, with a sea landing, the flight path is much more direct, allowing for the rockets to burn more fuel during the take-off stage and reach up to 9000 km/hr (5600 mi/hr) before it separates. This ability to burn more fuel and achieve higher speeds will be critical for long-term missions, like to the Moon or Mars, which will undoubtedly require a lot of heavy equipment and instrumentation. The Verge magazine has an excellent video explanation here.
Wow, that is cool! Why should I care?
Spaceflight is extremely expensive, currently costing around $10,000 a pound to put something in orbit, which means sending any person, satellite, or instrumentation to space costs millions of dollars. By the end of the space shuttle program, the price tag was astronomical (pun intended) $450 million per mission. In an era where NASA’s budget is but a fraction of what it was in the 1960’s, this high price tag makes progress into space painstakingly slow.
Why is going to space so pricey? For the majority of the space program thus far, booster rockets were single shot; they brought their cargo into orbit, separated, then fell back to Earth, either burning up in the atmosphere or crashing into the ocean. This meant that a new rocket had to be built for every mission, a very expensive business model. Each SpaceX Falcon 9 rocket costs around $54 million, but only uses around $200,000 worth of fuel. If SpaceX can make their landings routine, it would drastically cut the cost of getting into orbit, bringing the cost per pound down from the thousands to the hundreds. This would make putting equipment and people into space much cheaper, ushering in a new era of space exploration were missions become more frequent.
Bonus: SpaceX rocket failure compilation video…with explosions!