Imagine a Starlink Network with a High Data Rate - From the Moon

One of the things that I remember most about the Apollo missions was the video downlinks - actually watching Neil Armstrong's "one small step for a man..." and scenes from all the missions on the moon's surface. Considering the technology of the times, a grainy, black and white video stream from the moon was probably the limit of what they could do. 

As you might expect, NASA wants to do better next time.

To that end, NASA announced this week that it had awarded a contract to Houston-based Intuitive Machines for "lunar relay services." Essentially this means Intuitive Machines will be responsible for building a small constellation of satellites around the Moon that will beam data back to Earth from the lunar surface.

"One of the requirements is a 4K data link," said Steve Altemus, co-founder and chief executive of Intuitive Machines, in an interview. "That kind of high fidelity data only comes from a data relay with a larger antenna than can be delivered to the surface of the Moon."

NASA is working toward developing a "Near Space Network" for communications out to 1 million miles from Earth; the moon is about 1/4 of that distance while the Lagrange Point L2 where the James Webb Space Telescope and the ESA's Euclid telescope are located is just inside the 1 million mile limit - about 932,000 miles. 

...Intuitive Machines' contract is worth as much as $4.82 billion over the next decade, depending on the level of communication services that NASA chooses to purchase.

The space agency is also expected to award a ground-based component of this network for large dishes to receive signals from near space, taking some of this burden off the Deep Space Network. Altemus said Intuitive Machines has also bid on this ground component contract.

I'm assuming you either immediately remember the name of Intuitive Machines or you're thinking "I think I've heard that name before... what did they do again?" They launched the largely successful first commercial landing on the moon. Maybe I should say "first commercial crash landing" because the lander (officially Odysseus and quickly renamed Odie) broke a leg on the approach to their landing spot and tipped over upon landing. The word "landing" only applied in the loosest sense of the word and the mission was a continuous string of "making do with what we got," but Intuitive Machines reported every paying customer was happy with their results. 

That mission was called IM-1. They've addressed a long checklist of things to go after and IM-2 is currently expected to fly before the end of this year, also to the south pole area. It carries a NASA payload called PRIME-1 (Polar Resources Ice Mining Experiment-1) that will hunt for water ice, which is thought to be abundant in the area.  

Then, approximately 15 months from now, the company is planning to launch another lander, IM-3. This mission is likely to carry the first data-relay satellite—each is intended to be about 500 kg, Altemus said, but the final design of the vehicles is still being finalized—to lunar orbit. Assuming this first satellite works well, the two following IM missions will each carry two relay satellites, making for a constellation of five spacecraft orbiting the Moon.

Two of the satellites will go into polar orbits and serve NASA's Artemis needs at the South Pole, Altemus said. Two more are likely to go into halo orbits, and a fifth satellite will be placed into an equatorial orbit. This will provide full coverage of the Moon not just for communications, but also for position, navigation, and timing.

The source article doesn't give much details on the size antennas that will be required, given the quote about "a larger antenna than can be delivered to the surface of the Moon." With no idea of any of the key radio parameters, I can't fill in the equations that would tell me how big those satellite antennas have to be. Everything I could come up with would ultimately be a WAG.

The IM-2 lander being prepared for hot-fire testing this week. Image credit: Intuitive Machines.