Noticed in Space This Week
Psst! If you have school kids in your life, you might want to read this to the end regardless of whether you think you’re interested.
News About Crewed Flight
The crew capsule for Boeing’s Starliner came back to Earth at last. It landed successfully. Nobody was in it. In my opinion, bringing it down with no crew inside was the right decision. The longer NASA postponed it, the more strongly I felt about not putting Butch Wilmore and Suni Williams at undue risk again by flying them in a capsule with thrusters that couldn’t be fully trusted.
Launching with known leaks in the system upset me. It brought back memories of Challenger. Boeing doesn’t like losing face from Starliner’s ever-slipping schedule and now from the question marks about its safety. Too bad, but I’m not taking pity on Boeing. Losing face is nowhere near as bad as losing crew would be.
The capsule has landed intact. Engineers can study it, figure out exactly what’s wrong and fix it. The astronauts are still aboard the International Space Station. That’s a safer place for them than taking a chance in an iffy new vehicle. They’ll come home later. I’ve been concerned about their situation and now I need not be concerned about it any more.
News About Uncrewed Flight
Meanwhile, elsewhere in orbit, there’s a new kid on the block. It’s a solar sail being tested by NASA. It isn’t the first (that was Ikaros, a Japanese spacecraft, in 2010) but it’s the latest step in solar sail experimentation.
Using sunlight in a sail like a boat on water uses wind in a sail may sound like magic, but it’s physics. Credit for the most important physics involved goes to Louis de Broglie, a French physicist. His ideas didn’t get much credence until Albert Einstein read his thesis and supported his theories. Much of modern physics traces back to de Broglie—his ideas provided a starting point for other scientists who went on to develop quantum theory.
We can understand the basics without going into deep detail. In essence, he realized:
Energy has mass, like matter does
Matter has properties of energy, such as waves or wavelength
He came up with math to calculate the wavelength of a mass and the mass of a unit of energy such as a photon. Then the chase was on to test his theory. By 1927 other scientists began proving this strange-sounding idea. Electrons, which are tiny bits of matter, orbit the nucleus of atoms in ways that are neatly explained if they have wavelike properties and don’t make much sense otherwise.
I mentioned a photon. That’s a unit of light. Photons are so tiny, we can think of them as being for light much like what atoms are for matter—they are fundamental building blocks. Your desk, chair, tea or coffee mug, everything tangible is matter and matter is built of atoms. The light coming from your desk lamp, the sun, a display screen, or any other light source is a stream of photons.
According to de Broglie, each photon has a wavelength because it is energy and it also has mass.
Now add that to Sir Isaac Newton. He said every action has an equal and opposite reaction. Newtonian physics is what we witness on a billiards table. If one mass (a billiard ball) is moving fast and hits another mass that isn’t moving (another billiard ball), momentum transfers when the two masses (the two balls) touch.
You don’t need to hit a billiard ball with another of the same size and weight to make it move. You can assail the ball with lots of fast-moving marbles instead. Each marble transfers a small amount of momentum and the total effect of many marbles adds up to move the billiard ball.
That’s the idea behind NASA’s experiment in orbit right now.
A solar sail isn’t intended to capture the energy of photons to make electricity like a solar panel on a house. A solar sail is intended to be hit by the mass of photons. The photons each have only tiny mass compared with the mass of the sail, but the sail is bombarded by a stream of them from the sun. They are moving very fast (at the speed of light) so they have lots of momentum for their size. It’s like assailing a billiard ball with a flood of high-speed marbles.
If we can learn to use a solar sail, we can send spacecraft on long voyages out into the solar system without much fuel. They will only need enough fuel for maneuvers that can’t be done by simply tilting the sail. The spacecraft wouldn’t be speedy, but uncrewed exploratory flights don’t have to be speedy and sometimes prefer to go slowly past whatever they are studying.
Solar sails have been science fiction for a long time. Now they’re beginning to be science fact.
Meanwhile, Here On The Ground
As for what you can personally do with this post… School is starting again in the northern hemisphere. If you don’t see at least one science project here that you could do with a grade school student, look again.
Boeing’s reputation has slid dramatically and is indicative of profits over safety, though they don’t seem to understand the effect of quality control on profits. Space is still the Final Frontier on many levels. Human achievements in physics and in space are incredible and have given us the micro computer world we enjoy today. Let’s hope we won’t use it purely as a profit center and our scientific quest for knowledge will continue for its own benefit.