Christian Hahn Starlink capture showing guard region.

Analyzing Starlink Satellite Downlink Communications With Software Defined Radio

November 26, 2021 by Maya Posch 23 Comments

Often, mere curiosity is sufficient to do something. This is also the case with people trying to analyze the communication setup and protocol which SpaceX is using with their Ku-band based Starlink satellites. One of these fine folk is [Christian Hahn], who has recently posted some early findings to r/StarlinkEngineering over at Reddit. Some of the captured data seems to include the satellite ID system that ground-based user stations would presumably use to keep track of overhead Starlink satellites.

For the capturing itself, [Christian] is using a second-hand dish for capture and a DIY SDR using KC705 FPGA-based hardware – which may have begun its life as crypto mining hardware – along with the usual assortment of filters and other common components with this kind of capture. Even at this early time, some features of the Starlink protocol seem quite obvious, such as the division into channels and the use of guard periods. Nothing too earth-shattering, but as a fun SDR hobby it definitely checks all the boxes.

[Christian] has also announced that at some point he’ll set up a website and publish the findings and code that should make Starlink signal analysis easy for anyone with a readily available SDR receiver.

Find Your Way In The Starry Skies With DobsonianDSC

November 25, 2021 by Maya Posch 13 Comments

An obvious problem with the use of a telescope is getting the former to point at the proper part of the sky which you intend to observe, or vice versa when you spot something interesting and wish to record the exact location. While all of this can be done manually with some trouble, there’s a lot to be said for automating this process. Unfortunately these Digital Setting Circles (DSC) features are not cheap even as add-on, which is why [Vladimir Atehortúa] created DobsonianDSC as a low-cost DIY solution.

As the name suggests, this project is based around a Dobsonian-style telescope: Newtonian tube with simple altazimuth base. Aside from the mechanical construction, this system uses an ESP32 as its controller along with two rotary encoders, with the simple circuit detailed in a build guide. The firmware for the ESP32 is written in the Arduino C dialect, and a guide for flashing the ESP32 with the Arduino IDE and connecting it to the WLAN is provided as well.

After setup, the resulting telescope system can be used either via WiFi or Bluetooth from existing apps such as SkySafari that support the ‘Basic Encoding System’. An initial calibration is required, but after that you should have a telescope that works in concert with SkySafari or similar to automate this tedious part of astronomy away.

Obviously this is not a ready-to-install system, as every telescope is shaped and sized differently, but inspiration for mounting solutions is provided as well.

Blue Origin Rolls Out Test Article For Next-Gen Rocket

November 22, 2021 by Tom Nardi 28 Comments

By any metric you care to use, this is a very exciting time for America’s space program. NASA is refocusing their efforts towards the Moon and beyond, SpaceX is launching routine crew and cargo flights to the International Space Station with reusable rockets, and if you’ve got deep enough pockets, there are now multiple companies offering suborbital pleasure trips requiring little more than a few hours worth of training. It’s taken longer than many people had hoped, but it seems we’re finally making the confident strides necessary to truly utilize space’s vast resources.

But things are just getting started. A new generation of massive reusable rockets are currently being developed, which promise to make access to space cheaper and faster than ever before. We’ve seen quite a bit of SpaceX’s Starship, thanks in no small part to the dramatic test flights that the media-savvy company has been regularly live streaming to YouTube. But Blue Origin, founded by Amazon’s Jeff Bezos, has been far more secretive about their New Glenn. That is, until now.

On November 8th, Blue Origin rolled out their GS1 simulator for the New Glenn’s first stage. This stand-in for the real rocket will never fly, but it’s designed to perfectly recreate the dimensions, center of gravity, and mass, of the real thing. Ground teams will use the GS1 to practice safely transporting the booster, which is approximately half the length of the Saturn V, from their production facility to Launch Complex 36 (LC-36) at Cape Canaveral. It will also be used to test the fit and function of various pieces of ground support equipment, and eventually, the second stage stacking procedure.

For the uninitiated, it might seem like this is a lot of fuss over what’s ultimately just a hollow metal tube. But the introduction of a test article such as this has traditionally been a major milestone during the design and construction of rockets and spacecraft, dating back to the “boilerplate” test capsules used during the Mercury, Gemini, and Apollo programs; a sure sign that what was just an idea is now becoming a reality.

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There Were Almost Jet Packs On The Moon

November 18, 2021 by Al Williams 21 Comments

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.

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NASA’s New Moon Missions Are Happening Really Soon

November 9, 2021 by Lewin Day 40 Comments

NASA first landed a human on the moon back in 1969, and last achieved the feat in December 1972. In the intervening years, there have been few other missions to Earth’s primary natural satellite. A smattering of uncrewed craft have crashed into the surface, while a mere handful of missions have achieved a soft landing, with none successful from 1976 to 2013.

However, NASA aims to resume missions to the lunar surface, albeit in an uncrewed capacity at this stage. And you won’t have to wait very long, either. The world’s premier space agency aims to once again fly to the Moon beginning in February 2022.

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South Korean KSLV-2 Nuri Rocket Almost Orbits

November 8, 2021 by Chris Lott 4 Comments

There was a bit of excitement recently at the Naro Space Center on Outer Naro Island, just off the southern coast of the Korea Peninsula. The domestically developed South Korean Nuri rocket departed on its inaugural flight from launch pad LB-2 at 5pm in the afternoon on Thursday, 21 Oct. The previous launch in the KSLV-2 program from this facility was in 2018, when a single-stage Test Launch Vehicle was successfully flown and proved out the basic vehicle and its KRE-075 engines.

This final version of the three-stage Nuri rocket, formally known as Korean Space Launch Vehicle-II (KSLV-2), is 47.2 m long and 3.5 m in diameter. The first stage is powered by a cluster of four KRE-075 sea-level engines having 3 MN of thrust. The second stage is a single KRE-075 vacuum engine with 788 kN thrust, and the final stage is a KRE-007 vacuum engine with 69 kN thrust (all these engines are fueled by Jet-A / LOX). In this maiden flight, the first two stages performed as expected, but something went wrong when the third stage shut off prematurely and failed to gain enough velocity to put the 1400 kg dummy satellite into orbit.

A committee formed to investigate the flight failure convened this week, and issued a statement after a preliminary review of the collected telemetry data. So far, all indications point to a drop in oxidizer tank pressure in the third stage. This could be the result of a leak in the tank itself or the associated plumbing. They will also investigate whether a sensor or other failure in the tank pressurization control system could be at fault. A second launch is currently scheduled for May of next year. Check out [Scott Manley]’s video below the break, where he discusses the launch itself and some history of South Korea’s space program.

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Space Shuttle Model In A Hypersonic Wind Tunnel

Mach 20 In A Wind Tunnel: Yes, It’s Rocket Science

November 4, 2021 by Ryan Flowers 5 Comments

Hypersonic speeds are defined by those exceeding Mach 5, and lately there’s been a lot of buzz about unmanned hypersonic vehicles making test flights. Vehicles returning from orbital flight also travel at hypersonic speeds as they do their best to transition back to the terrestrial realm. Before anything leaves ground though, these machines are tested in wind tunnels. [Scott Manley]’s video “How Hypersonic Wind Tunnels Recreate Mach 20” (embedded below) does a wonderful job of explaining the engineering behind wind tunnels for testing hypersonic vehicles.

While the earliest wind tunnels such as that used by the Wright Brothers were powered by simple fans, it is not possible for any propeller to surpass subsonic speeds. This is evidenced by there not being any propeller driven aircraft that can exceed Mach 1. Since an aircraft can’t reach those speeds with a propeller, it follows that a wind tunnel cannot be driven by propellers, fans, or any such device, and exceed Mach 1 wind speed, either. So it begs the question: Just how do they do it?

You might think that the answer lays in Bernoulli’s law – but it does not. You might think it involves compressing the air into smaller and smaller tubes and pipes. It doesn’t. As [Scott Manley] so expertly explains in the video below the break, it has quite a lot in common with actual rocket science.

You may be interested to know that we’ve covered some DIY wind tunnel builds as well as a small desktop wind tunnel in the past. While not hypersonic, they’re exactly what you’d want to have if you’re an aerospace hacker of any kind.

Thanks [Zane Atkins] for the tip!

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