Can Ham Radio Operators Really Talk to the International Space Station?
Have you ever glanced up at the night sky, caught a glimpse of that bright, fast-moving dot—the International Space Station (ISS)—and wondered if the people inside could actually hear you? What if I told you that, with a bit of know-how and some radio gear, you could have a real conversation with astronauts living 250 miles above Earth? It sounds like the stuff of science fiction, but for thousands of ham radio operators around the globe, it’s an exhilarating reality.
Whether you’re a tech enthusiast, a sky-watcher, or simply someone who loves connecting with people around the world, the world of ham radio offers a doorway to some truly extraordinary experiences—including contacting the ISS. In this two-part series, I’ll walk you through how ham radio makes global (and even space-based) connections possible, the technology behind it, and how you can get in on the action yourself. So, let’s start by diving into the fascinating universe of ham radio and how it set the stage for Earth-to-space conversations.
The Fascinating World of Ham Radio
If you’re new to ham radio (also known as amateur radio), you’re in for a treat. ham radio is a hobby—and a service—that brings together people with a shared love for communication, technology, and discovery. For over a century, ham radio operators, affectionately called “hams,” have been using radio waves to connect with each other across cities, countries, and continents. It’s a world where you can make friends from Argentina to Zimbabwe, experiment with antennas and electronics, or lend a hand during emergencies—all with the twist of a dial.
A Brief History and Purpose
Ham radio traces its roots back to the early 20th century, when radio technology was just taking off. By the 1920s, amateur operators were already making their voices—and Morse code clicks—heard around the world. Unlike commercial broadcasters or cellphone users, hams operate on special frequency bands set aside by governments specifically for non-commercial, personal communication, experimentation, and public service. During disasters, when phone lines and the internet go down, ham radio is often a lifeline for emergency responders and communities.
What really makes ham radio unique, though, is its spirit of curiosity and camaraderie. There are nearly 3 million licensed operators worldwide, including more than 750,000 in the United States alone, according to the American Radio Relay League (ARRL). Hams span all ages and backgrounds, but they share a passion for tinkering, learning, and reaching out—sometimes to the most unexpected places.
Global (and Off-World!) Connections
One of the coolest aspects of ham radio is its ability to break down barriers—not just national borders, but even the boundary between Earth and space. Hams have long enjoyed “DXing,” or making contacts with faraway stations. It’s not uncommon to strike up a chat with someone in Japan, Australia, or South Africa during a good propagation day.
And then there are the stories that truly push the limits—like contacting an operator on a remote island, a research station in Antarctica, or even an astronaut circling the globe at 17,500 miles per hour aboard the ISS. In fact, thousands of operators have heard their call signs answered by someone floating in microgravity, thanks to amateur radio equipment installed on the space station.
To become part of this community, you’ll need a basic license (in the U.S., that’s the Technician class), which involves a simple test on radio rules and basic electronics. A starter handheld radio can cost less than $50, and you don’t need a massive antenna farm to get going. More advanced licenses and equipment let you reach farther and experiment more—but the community is famously welcoming to beginners.
The ISS and Its Ham Radio Capabilities
So, what’s the deal with the International Space Station? The ISS is a marvel of modern science—a gigantic orbiting laboratory that’s been continuously crewed by astronauts from dozens of countries since 2000. It circles the Earth about every 90 minutes, traveling at five miles per second. That means it’s frequently passing overhead, offering plenty of windows for radio contact.
But how did ham radio become part of the ISS mission? Enter the ARISS program—Amateur Radio on the International Space Station. This initiative was launched to promote science, technology, engineering, and math (STEM) education and to connect students and amateur operators with astronauts. Since its inception, ARISS has made possible over 1,400 scheduled school contacts and countless individual exchanges.
How the ISS Stays Connected
The station is equipped with a suite of radio gear: high-power transceivers, various antennas mounted on its exterior, and computerized systems to manage different communication modes. Astronauts use call signs like NA1SS (for the U.S. segment) and RS0ISS (for the Russian segment) when they’re on the air. The ISS can transmit and receive voice, send slow-scan television images, and even relay digital data packets—often using frequencies in the 2-meter (VHF) and 70-centimeter (UHF) amateur bands.
Every year, the ARISS program coordinates dozens of live contacts with schools and individual operators. In fact, according to ARISS, more than 75 astronauts and cosmonauts have participated in ham radio activities on the station, turning a distant speck in the night sky into a friendly, approachable voice.
Ready to find out how you can actually make contact with the ISS yourself? In Part 2, we’ll explore the step-by-step process, gear you’ll need, and tips to maximize your chances of making this once-in-a-lifetime connection. Stay tuned—it’s closer than you think!
How Do Ham Radio Operators Contact the ISS?
Picking up from where we left off, you now know that the ISS is fully equipped for ham radio and that astronauts are surprisingly accessible through the ARISS program. But how does a ham radio operator on Earth actually make that leap and talk to someone aboard the ISS? Let’s walk through the process—it’s a lot more approachable than you might think.
Step 1: Getting Licensed
First things first—before you can transmit on amateur radio frequencies, you’ll need a license. In the United States, this starts with passing the Technician class exam, which covers the basics of radio operation, safety, and regulations. There’s no Morse code requirement anymore, and there are plenty of online resources and local clubs ready to help you study (seriously, many hams love “Elmering” newcomers). Once you pass and receive your call sign, you’re legally on the air.
Step 2: Assembling Your Gear
You don’t need a NASA-sized budget for your setup. Many successful ISS contacts have been made with a simple handheld VHF/UHF transceiver (HT) and a modest antenna. While a larger directional antenna or a mobile radio can improve your odds, don’t let gear intimidation stop you. The most important factor is being able to transmit and receive on the frequencies the ISS uses—typically 145.800 MHz (downlink) and 145.990 MHz (uplink for North America).
Want to up your game? Some operators use tracking software or smartphone apps that predict when the ISS will be overhead, so you can be ready at the right time. Others build small “arrow” antennas that can be pointed by hand to follow the ISS as it zooms across the sky. Still, plenty of first-time contacts happen with just a stock “rubber duck” antenna, some luck, and good timing.
Step 3: Timing Your Attempt
The ISS orbits Earth every 90 minutes, but it’s only within range of your location for about 5 to 10 minutes per pass. The ARISS website, as well as tracking apps like Heavens-Above or ISS Tracker, can tell you when the next pass will occur and how high the station will rise above your horizon. High, overhead passes (more than 45° elevation) give you the best shot—less atmosphere and obstructions to block your signal.
Step 4: Making Contact
When the time comes, tune your radio to the appropriate frequency, aim your antenna (if you have one), and listen! Start by listening for activity—sometimes you’ll hear the astronauts calling CQ (the universal ham radio call for anyone to respond), or you might hear other hams making contacts. When you’re ready, wait for a break, announce your call sign, and try to keep your transmission brief—remember, there are likely dozens of others trying at the same time.
Exchanges are usually quick: state your call sign, your location, and maybe a word of thanks or encouragement. If you’re lucky and the astronaut has time, you might exchange a few more details, but given the short window, brevity is key.
Tips for Success
- Be patient—Many people try, and not every attempt is successful.
- Try multiple passes—If you don’t succeed on your first pass, try again; there are several opportunities each day.
- Use tracking apps to predict ISS passes and maximize your odds.
- Practice receiving first—Tune in and listen to other contacts before trying your own.
- Join local clubs or online groups for advice, encouragement, and real-time info.
Veteran ham operators love sharing stories of their first successful ISS contacts, and it’s easy to see why—it’s a special thrill to hear your signal bounce off a space station!
The Impact: Why Talking to the ISS Matters
At this point, you might be asking, “Okay, it’s cool—but why is this such a big deal?” Beyond the personal thrill, talking to the ISS has a ripple effect that reaches far beyond the ham community.
Inspiring the Next Generation
One of the cornerstone achievements of the ARISS program is its impact on education. ARISS arranges for schools worldwide to host live radio contacts with astronauts, allowing students—from kindergartners to high schoolers—to ask questions directly to the crew. Imagine being a ten-year-old and chatting with an astronaut in orbit! These events often spark lifelong interest in STEM fields and have even influenced some students to pursue careers in science, engineering, or space.
Fostering Global and Off-World Connections
Ham radio isn’t just about making a cool contact; it’s about building bridges. The ability to reach out—whether it’s across a continent or into low Earth orbit—strengthens an international community of explorers, learners, and citizen scientists. The ISS is unique: it’s a global venture, and its ham radio is a prime example of peaceful, educational outreach.
Astronauts Love It, Too
It’s not just hams and students on Earth who benefit. Many astronauts are licensed operators before they’re chosen for the ISS, and they jump at the chance to connect with “everyday” folks down below. Some have described these contacts as high points of their missions, giving them a direct, personal connection to people back on Earth.
By the Numbers: The Stats Behind ISS Ham Radio
Let’s take a look at some eye-opening statistics that showcase just how huge—and growing—this phenomenon really is:
- Worldwide operators: There are nearly 3 million licensed ham radio operators globally, with more than 750,000 in the United States alone (ARRL, 2023).
- ARISS contacts: Since 2000, ARISS has facilitated over 1,400 formal school contacts across 63 countries,
Fun Facts and Surprising Stories: Ham Radio and the ISS
Picking up from Part 2, we’ve learned how ham radio operators can reach the International Space Station and why these contacts inspire people all over the globe. But the world of ISS ham radio is packed with quirky trivia, remarkable achievements, and milestones that often fly under the radar—pun intended! Let’s dig in with ten fun facts that make this cosmic connection even more fascinating.
10 Fun Facts About Ham Radio and the ISS
1. The ISS Has Multiple Ham Radios Aboard
Most people imagine a single radio tucked away for emergencies, but the ISS actually has several amateur radio stations. They’re equipped for voice, packet (digital), and even slow-scan TV transmissions, and are mainly located in the Columbus (European) and Zvezda (Russian) modules.
2. School Kids Around the World Have Chatted With Astronauts
Thanks to ARISS (Amateur Radio on the International Space Station), more than 1,400 school groups worldwide have spoken directly to ISS crew members. These contacts often happen live, with entire classrooms gathered to ask questions—sometimes leading to future scientists and engineers.
3. You Can Receive Pictures from Space—No Internet Required
The ISS sometimes broadcasts “slow-scan television” (SSTV) images. These are transmitted as audio tones you can decode into pictures using free software—so anyone with a basic radio receiver and the right timing can collect space selfies!
4. Astronauts Use Special Call Signs
While on the air, American astronauts typically use the call sign NA1SS, while Russians use RS0ISS. These unique call signs help amateurs recognize when they’re hearing the real deal.
5. Contacts Are Brief—But Memorable
A typical radio “QSO” (contact) with the ISS lasts just a few seconds to a minute due to the station’s rapid movement and short window overhead. But those few seconds are often the highlight of a ham’s year!
6. Some ISS Astronauts Became Hams Just for the Mission
Many astronauts get their amateur radio licenses specifically so they can participate in ARISS events and talk to Earth. Samantha Cristoforetti (IZ0UDF) and Koichi Wakata (KC5ZTA) are just two of the many spacefarers who caught the ham bug.
7. The ISS Moves FAST
Traveling at about 17,500 mph (28,000 km/h), the ISS orbits Earth every 90 minutes. That’s why you only have roughly 5–10 minutes for a possible contact during a given pass.
8. You Don’t Need Fancy Gear to Hear the ISS
Plenty of people have received ISS voice or SSTV signals with nothing more than a handheld radio and a simple antenna. Some even use scanners or software-defined radios attached to laptops.
9. Packet Radio Lets You “Text” the Space Station
The ISS regularly transmits and receives “packet radio” (digital messages, like text emails) on amateur frequencies. Operators all over the world send and receive brief digital messages via this orbital digipeater.
10. Ham Radio on the ISS Is a Backup Communication System
Beyond education and fun, ham radio provides a critical backup. In rare cases, if other communication systems fail, the ISS crew can use amateur radio to call for help—just like during the Mir space station’s famous power loss in 1997.
Author Spotlight: Meet Kenneth Ransom, N5VHO
No conversation about ham radio and the ISS is complete without mentioning Kenneth Ransom, call sign N5VHO. As the ARISS Operations Lead at NASA’s Johnson Space Center, Ken has been instrumental in planning ham radio contacts between astronauts and Earthbound hams since the program’s inception.
Ken’s expertise bridges technical know-how and educational outreach. He’s coordinated hundreds of school contacts, trained astronauts on radio use, and helped keep the ISS’s amateur radio hardware up and running—even troubleshooting issues from the ground while the station orbits overhead! Ken is a ham operator himself, and he often shares behind-the-scenes stories at hamfests and in publications like QST magazine or on ARISS.org.
Thanks to Ken and the entire ARISS team, the ISS remains one of the most awe-inspiring and accessible “DX” stations (distant contacts) in the world, making dreams come true for students and seasoned amateurs alike.
Up Next: Your ISS Ham Radio FAQ
Now that you know the coolest facts and some of the people behind the program, you might be eager to try contacting the ISS yourself—or maybe you’re curious about the details. In the next section, we’ll answer some of the most common (and surprising) questions about ham radio and the International Space Station. Stay tuned for the ultimate FAQ!
Frequently Asked Questions: Ham Radio and the International Space Station
After exploring how ham radio operators contact the ISS, the inspiring stories behind these cosmic conversations, and the remarkable people who make them possible, you might still have a few questions. Let’s wrap up with a handy FAQ that covers the burning questions most newcomers—and even some seasoned hams—often ask.
1. Can anyone with a ham radio license talk to the ISS?
Yes! Any licensed amateur radio operator can try to contact the ISS during their orbital passes. The most common opportunities occur when the astronauts have set aside “general” contact times (sometimes called “random” or “unscheduled” contacts). You don’t need to be a pro—a Technician class license (in the U.S.) and a VHF/UHF radio are enough to get started.
2. What frequencies are used to contact the ISS?
The main frequency to listen for voice downlink from the ISS is 145.800 MHz (FM, VHF band). The uplink (your transmission to the ISS) is usually on 145.990 MHz for North America. However, these can vary depending on the mode (voice, packet, or SSTV) and which country you’re in. The ARISS website always posts the latest frequency updates.
3. How do I know when the ISS will pass over my location?
There are plenty of tools to help! Websites like [Heavens-Above](https://www.heavens-above.com/) and apps like ISS Tracker or AMSAT’s online resources let you input your location and see upcoming passes. Look for passes with the highest elevation above the horizon for the best results—typically 5-10 minutes long.
4. Do I need a special antenna or expensive equipment?
Not at all! Many successful contacts have been made with inexpensive handheld radios and stock antennas. Of course, directional “arrow” antennas or mobile rigs can improve your success rate, but beginners regularly score “space contacts” with basic setups. It’s all about timing, persistence, and a clear view of the sky.
5. What do I say to the astronauts or the ISS?
Keep it brief and clear. Start by stating your call sign, location, and a quick greeting or question. Astronauts are usually juggling lots of calls, so exchanges are short—often just a few seconds. For example: “NA1SS, this is KJ4XYZ in Atlanta, thank you for the contact!” If you’re participating in a school ARISS contact, you might get to ask a longer question as part of a scheduled event.
6. Can I hear the ISS even if I don’t have a ham license?
Absolutely! Anyone with a VHF receiver or scanner that covers 145.800 MHz can listen to ISS transmissions as it passes overhead. It’s a thrill to hear astronauts’ voices or receive slow-scan TV images, even if you’re not transmitting.
7. How do I get proof of my contact (a QSL card)?
After a successful contact, you can request a QSL card—an official confirmation of your contact with the ISS. ARISS and NASA have instructions on their websites for submitting contact logs. These cards are prized keepsakes for hams, and some operators even frame them! It’s a tradition rooted in ham radio culture and makes this achievement even more memorable.
8. What is “ARISS” and how does it help?
ARISS (Amateur Radio on the International Space Station) is a global partnership that supports amateur radio operations aboard the ISS. They coordinate school contacts, keep equipment running, and provide up-to-date info on frequencies and events. Their website, [ariss.org](https://www.ariss.org/), is the best hub for resources, contact schedules, and educational opportunities.
9. Are there any biblical principles that relate to this experience?
Definitely! The joy of connecting people across nations—and even into space—echoes the message of unity and wonder found in the Bible. As Psalm 19:1 (NKJV) declares, “The heavens declare the glory of God; and the firmament shows His handiwork.” Each conversation across the void reminds us of the incredible universe we share and the potential for harmony and learning.
10. Where can I learn more or get help from experts?
Start with the [ARISS website](https://www.ariss.org/) and organizations like [ARRL](https://www.arrl.org/), which offer tons of guides and local contacts. You can also check out expert blogs like [KB6NU Radio Blog](https://www.kb6nu.com/) or connect with local ham radio clubs. If you’re interested in school or youth outreach, ARISS provides step-by-step info on how to set up a student contact event.
Wrapping Up: Reach for the Stars—And Call Them!
From the basics of ham radio, through the ins and outs of making a space contact, to fun facts and legendary figures like Kenneth Ransom (N5VHO), we’ve seen how accessible—and downright inspiring—ISS ham radio can be. You don’t need to be a rocket scientist to join this adventure; just curiosity, a bit of preparation, and the willingness to try.
Thousands of hams, students, and curious listeners have already broken the barrier between Earth and orbit. Why not you? Whether your dream is to chat with an astronaut, inspire a classroom, or simply hear the ISS whiz overhead, the world of ham radio is ready to welcome you. As we’re reminded in Psalm 19:1, “The heavens declare the glory of God,” and what better way to witness that than by reaching up