Elon Musk’s adventure in space
On Saturday, SpaceX launched the unmanned Crew Dragon capsule on a Falcon 9 rocket. A little more than 24 hours later, the Crew Dragon docked successfully with the International Space Station. SpaceX CEO Elon Musk and his team are right to celebrate this tremendous achievement.
Although the relative motions are slow, the ISS zips along at about 5 miles every second, or approximately 18,000 mph. To dock with the ISS, Crew Dragon had to reach the same speed in exactly the same orbit — no easy feat — and to line up precisely with the docking port, approaching slowly enough (in relative terms) to not damage either vehicle.
This kind of thing is both very difficult and surprisingly old hat.
The ability to dock two spacecraft was first demonstrated over 50 years ago, when the Gemini 8 crew connected with an unmanned target vehicle in 1966. The Russians caught up a year and a half later, when they successfully mated two Cosmos spacecraft.
Then as now, the Russians and United States were leaders in space. What’s different about the SpaceX docking feat is that it’s a private company, not a government, that’s in charge of the operation.
After 2011, when NASA retired the Space Shuttle after 30 years and 135 flights, astronauts had to be ferried to and from the ISS on Russian Soyuz spacecraft. Developing a new crewed capability has been a priority for NASA, and by extension, the private aerospace industry it helps support.
Rockets take crew and/or cargo into space. But to transfer either to the ISS means the two need to dock. Early in the US program, NASA figured out that the maneuver was far more difficult than, say, a relay race or airplanes refueling midflight.
That’s because orbital dynamics are governed by gravity. As any first-year physics student learns, the speed of a satellite and the radius of its orbit are tightly linked. So, when a spacecraft uses its thrusters to speed up a bit and catch up to another spacecraft, the radius of its orbit automatically increases, meaning the laws of physics move the chase craft away even as it aims for the target craft.
In 1965, Wally Schirra, one of the first US astronauts, succeeded in piloting Gemini 6 to within 40 meters of Gemini 7. This demonstration that one spacecraft could maneuver precisely enough to match the orbit of another spacecraft is what made the act of docking possible.
Today, some aspects of docking are easier than they used to be. Computers are exponentially more powerful than they were in the 1960s. Back then, self-driving cars were science fiction, whereas now the technology of computer-assisted driving is a reality.
Still, it’s remarkable to reflect that we are redeveloping skills that were first developed many decades ago. And that it’s nontrivial to repeat the technical achievements of the 1960s Mercury, Gemini and Apollo programs.
What lessons might be learned from the difficulty of maintaining expertise over many decades?
First, what is forgotten takes time to be relearned. It is far easier to maintain knowledge, and advance gradually, than to restart a process from the beginning.
Second, difficult tasks like spaceflight take smart people and computers. Both require funding. High-level jobs and technical advances are a valuable investment, though critics balk at the spending. We need to recognize the inherent value in maintaining and extending expertise.
Third, the relatively recent involvement of private space companies in spaceflight doesn’t change the underlying funding picture. Huge challenges like access to space are ultimately funded by taxpayers; that is, NASA pays SpaceX for its services and, at least until the market expands significantly, it remains a big part of the financial picture.
Being able to access space reliably is a commitment. And it’s better, faster and cheaper to stay committed than to change our minds every few years.