Listening To The ISS On The Cheap

June 10, 2023 by Dan Maloney 36 Comments

Like any hobby, amateur radio has no upper bounds on what you can spend getting geared up. Shacks worth tens of thousands of dollars are easy to come by, and we’ll venture a guess that there are hams out there pushing six figures with their investment in equipment. But hands down, the most expensive amateur radio station ever has to be the one aboard the International Space Station.

So what do you need to talk to a $100 billion space station? As it turns out, about $60 worth of stuff will do, as [saveitforparts] shows us in the video below. The cross-band repeater on the ISS transmits in the 70-cm ham band, meaning all that’s needed to listen in on the proceedings is a simple “handy talkie” transceiver like the $25-ish Baofeng shown. Tuning it to the 437.800-MHz downlink frequency with even a simple whip antenna should get you some reception when the ISS passes over.

In our experience, the stock Baofeng antenna isn’t up to the job, so something better like the Nagoya shown in the video is needed. Better still is a three-element Yagi tuned down slightly with the help of a NanoVNA; coupled with data on when the ISS will be within line-of-sight, picking up the near-constant stream of retransmissions from the station as Earth-based hams work it should be a snap — even though [saveitforparts] only listened to the downlink frequency here, for just a bit more of an investment it’s also possible for licensed hams to uplink to the ISS on 145.900 MHz.

For those who want a slightly higher level of difficulty, [saveitforparts] also has some tips on automating tracking with an old motorized mount for CCTV cameras. Pitchfork notwithstanding, it’s not the best antenna tracker, but it has promise, and we’re eager to see how it pans out — sorry. But in general, the barrier to entry for getting into space communications is so low that you could easily make this a weekend project. We’ve been discussing this and other projects on the new #ham-shack channel over on the Hackaday Discord. You should pop over there and check it out — we’d be happy to see you there.

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NASA Team Sets New Space-to-Ground Laser Communication Record

June 9, 2023 by Joseph Long 13 Comments

[NASA] and a team of partners has demonstrated a space-to-ground laser communication system operating at a record breaking 200 gigabit per second (Gbps) data rate. The TeraByte InfraRed Delivery (TBIRD) satellite payload was designed and built by [MIT Lincoln Laboratory]. The record of the highest data rate ever achieved by a space-to-Earth optical communication link surpasses the 100 Gbps record set by the same team in June 2022.

TBIRD makes passes over an ground station having a duration of about six-minutes. During that period, multiple terabytes of data can be downlinked. Each terabyte contains the equivalent of about 500 hours of high-definition video. The TBIRD communication system transmits information using modulated laser light waves. Traditionally, radio waves have been the medium of choice for space communications. Radio waves transmit data through space using similar circuits and systems to those employed by terrestrial radio systems such as WiFi, broadcast radio, and cellular telephony. Optical communication systems can generally achieve higher data rates, lower loses, and operate with higher efficiency than radio frequency systems. Continue reading “NASA Team Sets New Space-to-Ground Laser Communication Record” →

The Glitch That Brought Down Japan’s Lunar Lander

June 3, 2023 by Matthew Carlson 36 Comments

When a computer crashes, it usually doesn’t leave debris. But when a computer happens to be descending towards the lunar surface and glitches out, that’s a very different story. Turns out that’s what happened on April 26th, as the Japanese Hakuto-R Lunar lander made its mark on the Moon…by crashing into it. [Scott Manley] dove in to try and understand the software bug that caused an otherwise flawless mission to go splat.

The lander began the descent sequence as expected at 100 km above the surface. However, as it descended, the altitude sensor reported the altitude as much lower than it was. It thought it was at zero altitude once it reached about 5 km above the surface. Confused by the fact it hadn’t yet detected physical contact with the surface, the craft continued to slowly descend until it ran out of fuel and plunged to the surface.

Ultimately it all came down to sensor fusion. The lander merges several noisy sensors, such as accelerometers, gyroscopes, and radar, into one cohesive source of truth. The craft passed over a particularly large cliff that caused the radar altimeter to suddenly spike up 3 km. Like good filtering software, the craft reasons that the sensor must be getting spurious data and filters it out. It was now just estimating its altitude by looking at its acceleration. As anyone who has tried to track an object through space using just gyros and accelerometers alone can attest, errors accumulate, and suddenly you’re not where you think you are.

We know what you’re thinking: surely they would have run landing simulations to catch errors like these? Ironically they did, it’s just that after the simulations were run, the landing site for Hakuto-R was changed. Unfortunately, nobody thought to re-run the simulations, and now the Moon has a new lawn ornament,

We’ve previously written about why lunar landings are so hard. While knowing what led to the crash will hopefully prevent a similar fate for future missions, the reality is that remotely landing a robot on a dusty world without the help of GPS is fiendishly difficult and likely will be for some time.

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South Korea Successfully Sends Satellites To Orbit

May 30, 2023 by Chris Lott 8 Comments

South Korea’s KARI ( Korea Aerospace Research Institute ) successfully put a commercial satellite into orbit Thursday, achieving another milestone in their domestic space program. The Nuri rocket (aka KLSV-2) left the Naro Space Center launch pad on the southern coast of the peninsula at 18:24 KST, after a communications glitch in the pad’s helium tank facility caused a one-day slip. The primary payload was the 180 kg refrigerator-sized Earth observation satellite NEXTSat-2. It uses synthetic aperture radar (SAR) and also has instruments to observe neutrons in near-Earth orbit due to the impact of solar activity on cosmic radiation. In addition, seven CubeSats were successfully deployed:

Justek JLC-101-V1.2, to verify satellite orbital control system
Lumir, measuring cosmic radiation and testing rad-hardened microprocessor design
Cairo Space, weather observation and space debris technology demonstration
KASI-SAT (Korea Astronomy and Space Science Institute) SNIPE, actually four nano-sats which will achieve a 500 km – 600 km polar orbit and fly in formation to measure plasma variations.

It seems that SNIPE-C, Justek, and Lumir are having communication troubles and may be lost. Ground controllers are still searching. This launch comes almost one year after the previous launch of a dummy satellite in June, which we wrote about last year.

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Bankruptcy Sale Scatters Virgin Orbit To The Winds

May 25, 2023 by Tom Nardi 19 Comments

When Virgin Orbit filed for bankruptcy in April, it was clear the commercial launch provider was in serious trouble. Despite successfully putting four payloads into low Earth orbit, the spin-off of Richard Branson’s Virgin Galactic space tourism company had struggled to achieve a high enough launch cadence to become profitable, and had recently suffered a highly-publicized failure when their first launch from the UK from the newly-completed Spaceport Cornwall ended in a complete loss of the vehicle.

There was some hope that a buyer would swoop in and save them at the last minute, but now that the bankruptcy auction has spread out the company’s assets among several other players in the commercial launch industry, Virgin Orbital is officially no more. With future launches now off the table, the company’s remaining employees are set to be let go as operations wind down over the coming weeks.

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Simulated ET To Phone Home From Mars This Afternoon

May 24, 2023 by Al Williams 31 Comments

In science fiction movies, communicating with aliens is easy. In real life, though, we think it will be tough. Today, you’ll get your chance to see how tough when a SETI project uses the European Space Agency’s ExoMars Trace Gas Orbiter to send a simulated alien message to the Earth. The transmission is scheduled to happen at 1900 UTC and, of course, the signal will take about 16 minutes to arrive here on planet Earth. You can see a video about the project, A Sign in Space, below.

You don’t need to receive the message yourself. That will be the job of observatories at the SETI Institute, the Green Bank Observatory, and the Italian National Institute for Astrophysics. They’ll make the signal available to everyone, and you can join others on Discord or work solo and submit your interpretation of the message.

There are a host of issues involved in alien communication. What communication medium will they use? How will they encode their message? Will the message even make sense? Imagine an engineer from 1910 trying to find, decode, and understand an ad on FM radio station 107.9. First, they’d have to find the signal. Then figure out FM modulation. Then they’d probably wonder what the phrase “smartphone” could possibly mean.

When [Frank Drake] created a test message to send to aliens via the Arecibo dish, almost no one could decode it unless they already knew how it worked. But even looking at the message in the accompanying image, you probably can only puzzle out some of it. Don’t forget; this message was created by another human.

If you want a foreshadowing of how hard this is, you can try decoding the bitstream yourself. Of course, that page assumes you already figured out that the stream of bits is, in fact, a stream of bits and that it should be set in an image pattern. You also have the advantage of knowing what the right answer looks like. It could easily become an extraterrestrial Rorschach test where you find patterns and meaning in every permutation of bits.

Speaking of the Drake message, it saddens us to think that Arecibo is gone. The closest we think we’ve come to intercepting alien messages is the Wow signal.

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Badminton Inspired Heat Shield Aims To Fly This Year

May 18, 2023 by Bryan Cockfield 15 Comments

Badminton is not a sport that most of us think about often, and extremely rarely outside of every four years at the summer Olympics and maybe at the odd cookout or beach party here or there. But the fact that it’s a little bit unique made it the prime inspiration for this new heat shield design, which might see a space flight and test as early as a year from now.

The inspiration comes from the shuttlecock, the object which would otherwise be a ball in any other sport. A weighted head, usually rubber or cork, with a set of feathers or feather-like protrusions mounted to it, contributes to its unique flight characteristics when hit with a racquet. The heat shield, called Pridwen and built by Welsh company Space Forge, can be folded before launch and then expanded into this shuttlecock-like shape once ready for re-entry. It’s unlikely this will protect astronauts anytime soon, though. The device is mostly intended for returning materials from the Moon or from asteroids, or for landing spacecrafts on celestial bodies with atmospheres like Mars or Venus.

With some testing done already, Space Forge hopes this heat shield will see a space flight before the close of 2023. That’s not the end of the Badminton inspiration either, though. It’s reported that this device can slow a re-entering craft so much that it can be caught in a net. Not exactly the goal when playing the sport, but certainly a welcome return home for whichever craft might use this system. Of course, getting down from space is only half the battle. Take a look at this other unique spacecraft that goes up in a fairly non-traditional way instead.