space

198 Articles

Space-Based Solar Power: Folly Or Stroke Of Genius?

August 24, 2022 by 137 Comments

The Sun always shines in space, unless a pesky planet gets in the way. That’s more or less the essential thought behind space-based solar power (SBSP) as newly pitched by ESA’s director general, Josef Aschbacher on Twitter. Rather than putting photovoltatic solar panels on the Earth’s surface which has this annoying property of constantly rotating said panels away from the Sun during what is commonly referred to as ‘night’, the panels would be put stationary in space, unaffected by the Earth’s rotation and weather.

Although a simple idea, it necessitates the solving of a number of problems. The obvious first question is how to get these panels up in space, hundreds of kilometers from the Earth’s surface, to create a structure many times larger than the International Space Station. The next question is how to get the power back to Earth, followed by questions about safety, maintenance, transfer losses and the inevitable economics.

With organizations ranging from NASA to China’s Academy for Space Technology (CAST), to US institutions and others involved in SBSP projects, it would seem that these problems are at the very least deemed to be solvable. This raises the question of how ESA’s most recent proposal fits into this picture. Will Europe soon be powered from orbital solar panel arrays?

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Laser Propulsion Could Satisfy Our Spacecraft’s Need For Speed

June 6, 2022 by 51 Comments

There are many wonderful places we’d like to visit in the universe, and probably untold numbers more that we haven’t even seen or heard of yet. Unfortunately…they’re all so darn far away. A best-case-scenario trip to Mars takes around six months with present technology, meanwhile, if you want to visit Alpha Centauri it’s a whole four lightyears away!

When it comes to crossing these great distances, conventional chemical rocket technology simply doesn’t cut the mustard. As it turns out though, lasers could hold the key to cutting down travel times in space!

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Can You Hear Me Now? Lunar Edition

May 16, 2022 by 9 Comments

Despite what it looks like in the movies, it is hard to communicate with astronauts from Earth. There are delays, and space vehicles don’t usually have a lot of excess power. Plus everything is moving and Doppler shifting and Faraday rotating. Even today, it is tricky. But how did Apollo manage to send back TV, telemetry, and voice back in 1969? [Ken Shirriff] and friends tell us part of the story in a recent post where he looks at the Apollo premodulation processor.

Things like weight and volume are always at a premium in a spacecraft, as is power. When you look at pictures of this solid box that weighs over 14 pounds, you’ll be amazed at how much is crammed into a relatively tiny spot. Remember, if this box was flying in 1969 it had to be built much earlier so there’s no way to expect dense ICs and modern packaging. There’s not even a printed circuit board. The components are attached to metal pegs in a point-to-point fashion. The whole thing lived near the bottom of the Command Module’s lower equipment bay.

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Mercury Thrusters: A Worldwide Disaster Averted Just In Time

April 18, 2022 by 60 Comments

The field of space vehicle design is obsessed with efficiency by necessity. The cost to do anything in space is astronomical, and also heavily tied to launch weight. Thus, any technology or technique that can bring those figures down is prime for exploitation.

In recent years, mercury thrusters promised to be one such technology. The only catch was the potentially-ruinous environmental cost. Today, we’ll look at the benefits of mercury thrusters, and how they came to be outlawed in short order.

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One Giant Leap (Backwards) For Humankind: What The Russia-Ukraine War Means For The ISS

March 21, 2022 by 89 Comments

The International Space Station was built not only in the name of science and exploration, but as a symbol of unity. Five space agencies, some representing countries who had been bitter Cold War rivals hardly a decade before the ISS was launched, came together to build something out of a sci-fi novel: a home among the stars (well, in Low Earth Orbit) for humans from around the globe to work with one another for the sake of scientific advancement, high above the terrestrial politics that governed rock below. That was the idea, at least.

So far, while there has been considerable sound and fury in social media channels, international cooperation in space seems to continue unhindered. What are we to make of all this bluster, and what effects could it have on the actual ISS?

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In 2045: Alpha Centauri

March 15, 2022 by 90 Comments

We’ve talked about project Breakthrough Starshot which aims to send a solar sail probe to Alpha Centauri within 20 years. A little basic math and knowing that Alpha Centauri is 4.3 light years away means you are going to need to travel over 20% of the speed of light to make the trip in that time. Some new papers have proposed ways to address a few of the engineering problems.

The basic idea is simple. A very small probe is attached to a very large sail. But calling it a solar sail is a bit of a misnomer. The motive power for the sail would be a powerful laser, which provides more reliable power to the tiny probe’s propulsion system. The problems? First, the thin sail could tear under constant pressure. The answer, according to one of the papers, is to shape the sail like a parachute so it can billow under pressure.

The other problem is not burning the sail up. Space is a hard environment to dump waste heat into since radiation is the only way to transfer it. Another paper suggests that nanoscale patterns on the sail will allow it to release waste heat into the interstellar environment.

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Ion Thrusters: Not Just For TIE Fighters Anymore

March 3, 2022 by 42 Comments

Spacecraft rocket engines come in a variety of forms and use a variety of fuels, but most rely on chemical reactions to blast propellants out of a nozzle, with the reaction force driving the spacecraft in the opposite direction. These rockets offer high thrust, but they are relatively fuel inefficient and thus, if you want a large change in velocity, you need to carry a lot of heavy fuel. Getting that fuel into orbit is costly, too!

Ion thrusters, in their various forms, offer an alternative solution – miniscule thrust, but high fuel efficiency. This tiny push won’t get you off the ground on Earth. However, when applied over a great deal of time in the vacuum of space, it can lead to a huge change in velocity, or delta V.

This manner of operation means that an ion thruster and a small mass of fuel can theoretically create a much larger delta-V than chemical rockets, perfect for long-range space missions to Mars and other applications, too. Let’s take a look at how ion thrusters work, and some of their interesting applications in the world of spacecraft!

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