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.
If you haven’t seen [Ken Shirriff]’s teardowns and reverse engineering expeditions, then you’re in for a treat. His explanation and demonstration of the Apollo digital ranging system is a fascinating read, even if vintage computing and engineering aren’t part of your normal fare.
The average Hackaday reader should be familiar with the concept of determining the distance of a faraway object by measuring how long it takes a sound or radio wave to be reflected, such as in sonar and radar. Going another step and measuring Doppler Shift – the difference in the returned signal’s frequency – will tell us the velocity of the object relative to our position. It’s so simple that an Arduino can do it. But in the days of Apollo, there was no Arduino. In fact, there were no Integrated Circuits. And Apollo missions went all the way to the moon- far too distant for relatively simple Radar measurements. Continue reading “The Apollo Digital Ranging System: More Than Meets The Eye”→
It’s often said that the wheels of government turn slowly, and perhaps nowhere is this on better display than at NASA. While it seems like every week we hear about another commercial space launch or venture, projects helmed by the national space agency are often mired by budget cuts and indecisiveness from above. It takes a lot of political will to earmark tens or even hundreds of billions of dollars on a project that could take decades to complete, and not every occupant of the White House has been willing to stake their reputation on such bold ambitions.
In 2019, when Vice President Mike Pence told a cheering crowd at the U.S. Space & Rocket Center that the White House was officially tasking NASA with returning American astronauts to the surface of the Moon by 2024, everyone knew it was an ambitious timeline. But not one without precedent. The speech was a not-so-subtle allusion to President Kennedy’s famous 1962 declaration at Rice University that America would safely land a man on the Moon before the end of the decade, a challenge NASA was able to meet with fewer than six months to spare.
Unfortunately, a rousing speech will only get you so far. Without a significant boost to the agency’s budget, progress on the new Artemis lunar program was limited. To further complicate matters, less than a year after Pence took the stage in Huntsville, there was a new President in the White House. While there was initially some concern that the Biden administration would axe the Artemis program as part of a general “house cleaning”, it was allowed to continue under newly installed NASA Administrator Bill Nelson. The original 2024 deadline, at this point all but unattainable due to delays stemming from the COVID-19 pandemic, has quietly been abandoned.
So where are we now? Is NASA in 2022 any closer to returning humanity to the Moon than they were in 2020 or even 2010? While it might not seem like it from an outsider’s perspective, a close look at some of the recent Artemis program milestones and developments show that the agency is at least moving in the right direction.
You no doubt recall the incredible Apollo Guidance Computer (AGC) reverse engineering and restoration project featured on the CuriousMarc YouTube channel a few years ago. Well, [Marc] and the team are at it again, this time restoring the Apollo Unified S-Band tracking and communication system flight hardware. As always, the project is well documented, carefully explained, full of problems, and is proceeding slowly despite the lack of documentation.
Like the guidance computer, the Unified S-Band system was pretty innovative for its day — able to track, provide voice communications, receive television signals, and send commands to and monitor the health of the spacecraft via telemetry. The system operates on three frequencies, an uplink containing ranging code, voice and data. There are two downlinks, one providing ranging, voice, and telemetry, the other used for television and the playback of recorded data. All crammed into two hefty boxes totaling 29 kg.
So far, [Marc] has released part 9 of the series (for reference, the Apollo Guidance Computer took 27 parts plus 8 auxiliary videos). There seems to be even less documentation for this equipment than the AGC, although miraculously the guys keep uncovering more and more as things progress. Also random pieces of essential ground test hardware keep coming out of the woodwork. It’s a fascinating dive into not only the system itself, but the design and construction techniques of the era. Be sure to check out the series (part 1 is below the break) and follow along as they bring this system back to life. [Marc] is posting various documents related to the project on his website. And if you missed the AGC project, here’s the playlist of videos, and the team joined us for a Hackaday Chat back in 2020.
When it comes down to it, we humans have two major concerns when venturing away from home for an extended period of time: what we’ll eat, and where we will sleep. Depending on the mode of travel, you might take some snacks along, or else rely on restaurants and/or the pantry of your possible hosts. Until the day we can reliably grow many types of food in space, or that Milliways, that five-star eatery at the end of the universe is operational, astronauts and other space-bound travelers will have to bring most of their food with them.
Cubes and Tubes
Space food has its roots in military rations, which in the United States were devised during the Revolutionary War. Both the variety and delivery methods of food have changed significantly since the beginning of the space program. While the menu may have at first been limited to tubes of nutrient-rich goo, bite-sized cubes and freeze-dried powdered beverages, the fare is more far-out these days. Astronauts on the ISS even enjoy tortillas, fresh fruits, and vegetables thanks to resupply missions, though they have to eat some of these types of foods quickly.
The average astronaut has also changed quite a bit, too. At first, they were all young and super-fit ex-military men, but nowadays they are more likely to be middle-aged science-y types and women. All three of these groups have different nutritional needs when faced with the rigors of living and working in space.
Here it is almost 2022 and we still don’t have our jet packs. But don’t feel bad. NASA astronauts wanted a lunar jetpack, but they didn’t get one either. [Amy] at The Vintage Space has an interesting video about what almost was, and you can see it below.
Of course, a jet pack on the moon would be easier than an Earthbound one. The goal was to allow the crew to range further from their lander since they couldn’t carry very much and the lander didn’t have a lot of consumables, either. In addition, if you lost sight of the lander, getting back could be a problem since navigating on the moon was an unknown skill.
In 1969 awarded exploratory contracts for lunar personal flying vehicles including one to Bell who had their Earth-bound jet pack that shows up every so often for example in Bond movies.
Since the Apollo program, astronauts making the nine mile trip from the Operations and Checkout Building to the launch pad have rode in a specialized van that’s become lovingly referred to as the Astrovan. The original van, technically a modified motorhome, was used from 1967 all the way to the first Shuttle missions in 1983. From then on, a silver Airstream Excella emblazoned with the NASA “meatball” carried crews up until the final Shuttle rolled to a stop in 2011.
With crewed flights for the Artemis lunar program on the horizon, NASA has put out a call to companies that want to build a new Crew Transportation Vehicle (CTV). As you might expect from rocket scientists, the space agency has provided an exacting list of specifications for the new CTV, down to the dimensions of the doors and how many amps each of its 12 VDC power jacks must be able to handle. Perhaps most notably, NASA requires that the new 8-seat Astrovan be a zero-emission vehicle; which given the relatively short distance it has to drive, shouldn’t actually be too difficult.
Interior of the Shuttle-era Astrovan
In the document, NASA explains that the new CTV could either be a completely new one-of-a-kind vehicle, or a commercially available vehicle that has been suitably modified, as was the case with the previous vans. But interestingly, it also says they’re open to proposals for refurbishing the Shuttle-era 1983 Airstream and putting it back into service.
This is particularly surprising, as the vehicle is currently part of the Atlantis exhibit at the Kennedy Space Center. Presumably the space agency thinks there would be some bankable nostalgia should Artemis crews ride to the pad in the same van that once carried the Shuttle astronauts, but given the vehicle’s history and the fact that it’s literally a museum piece, it seems somewhat inappropriate. This is after all the very same van that once carried the Challenger and Columbia crews to their ill-fated spacecraft. Luckily, the chances of anyone willing to turn a 1983 Airstream into a zero-emission vehicle seem pretty slim.
If you’re wondering, SpaceX carries astronauts to the pad in specially modified Tesla Model X luxury SUVs, and Boeing has already partnered with Airstream to build their own Astrovan II. There’s still no date on when Boeing might actually get their CST-100 Starliner up to the International Space Station, but at least the van is ready to go.
