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Tesseract makes spacecraft propulsion smaller, greener, stronger – TechCrunch



Launch vehicles and their enormous rocket engines tend to receive the lion’s share of attention when it comes to space-related propulsion, but launch only takes you to the edge of space — and space is a big place. Tesseract has engineered a new rocket for spacecraft that’s not only smaller and more efficient, but uses fuel that’s safer for us down here on the surface.

The field of rocket propulsion has been advancing constantly for decades, but once in space, there’s considerably less variation. Hydrazine is a simple and powerful nitrogen-hydrogen fuel that’s been in use since the ’50s, and engines using it (or similar “hypergolic” propellants) power many a spacecraft and satellite today.

There’s just one problem: Hydrazine is horribly toxic and corrosive. Handling it must be done in a special facility, using extreme caution and hazmat suits, and very close to launch time — you don’t want a poisonous explosive sitting around any longer than it has to. As launches and spacecraft multiply and costs drop, hydrazine handling remains a serious expense and danger.

Alternatives for in-space propulsion are being pursued, like Accion’s electrospray panels, Hall effect thrusters (on SpaceX’s Starlink satellites) and light sails — but ultimately, chemical propulsion is the only real option for many missions and craft. Unfortunately, research into alternative fuels that aren’t so toxic hasn’t produced much in the way of results — but Tesseract says the time has come.

“There was some initial research done at China Lake Naval Station in the ’90s,” said co-founder Erik Franks, but it fizzled out when funds were reallocated. “The timing also wasn’t right because the industry was still dominated by very conservative defense contractors who were content with the flight-proven toxic propellant technology.”

A live fire test of Tesseract’s Rigel engine.

The lapsed patents for these systems, however, pointed the team in the right direction. “The challenge for us has been going through the whole family of chemicals and finding which works for us. We’ve found a really good one — we’re keeping it as kind of a trade secret but it’s cheap, and really high-performance.”

You wouldn’t want to rinse your face with it, but you can fuel a spacecraft wearing Gore-Tex coveralls instead of a hermetically sealed hazmat suit. Accidental exposure doesn’t mean permanent tissue damage like it might with hydrazine.

The times have changed, as well. The trend in space right now is away from satellites that cost hundreds of millions and stay in geosynchronous orbit for decades, and toward smaller, cheaper birds intended to last only five or 10 years.

More spacecraft being made by more people makes safer, greener alternatives more attractive, of course: lower handling costs, less specialized facilities and so on further democratize the manufacturing and preparation processes. But there’s more to it than that.

If all anyone wanted was to eliminate hydrazine-based propulsion, they could replace the engine with an electric option like a Hall effect thruster, which gets its thrust from charged particles exiting the assembly and imparting an infinitesimal force in the opposite direction — countless times per second, of course. (It adds up.)

But these propulsion methods, while they have a high specific impulse — a measurement of how much force is generated per unit of fuel — they produce very little thrust. It’s like suggesting someone take a solar-powered car with a max speed of 5 MPH instead of a traditional car with a V6. You’ll get there, and economically, but not in a hurry.

Consider that a satellite, once brought to low orbit by a launch vehicle, must then ascend on its own power to the desired altitude, which may be hundreds of kilometers above. If you use a chemical engine, that could be done in hours or days, but with electric, it might take months. A military comsat meant to stay in place for 20 years can spare a few months at the outset, but what about the thousands of short-life satellites a company like Starlink plans to launch? If they could be operational a week after launch rather than months, that’s a non-trivial addition to their lifespan.

“If you can get rid of the toxicity and handling costs of conventional chemical propulsion, but maintain performance, we think green chemical is a clear winner for the new generation of satellites,” Franks said. And that’s what they claim to have created. Not just on paper either, obviously; here’s a video of a fire test from earlier this year.

“It’s also important at end of life, where doing a long, slow spiral deorbit, repeatedly crossing the orbits of other satellites, dramatically increases the risk of collision,” he continued. “For responsibly managing these large, planned constellations the ability to quickly deorbit at end of life will be especially important to avoid creating an unsustainable orbital debris problem.”

Tesseract has only seven full-time employees, and was a part of Y Combinator’s Summer 2017 class. Since (and before) then they’ve been hard at work engineering the systems they’ll be offering, and building relationships with aerospace.


A render of Tesseract’s two flagship products — Adhara on the left and Polaris on the right.

They’ve raised a $2 million seed round, but you don’t have to be a rocket scientist to know that’s not the kind of money that puts things into space. Fortunately, the company already has its first customers, one of which is still in stealth but plans to launch a Moon mission next year (and you better believe we’re following up on that hot tip). The other is Space Systems/Loral, or SSL, which has signed a $100 million letter of intent.

There are two main products Tesseract plans to offer. Polaris is a “kickstage,” essentially a short-range spacecraft used to deliver satellites to more distant orbits after being taken up to space by a launch vehicle. It’s powered by the company’s larger Rigel engines; this is the platform purportedly headed to the Moon, and you can see it propelling a clutch of 6U smallsats on the right in the image above.

But Franks thinks the money is elsewhere. “The systems we think will be a bigger market opportunity are the smallsat propulsion systems,” he said. Hence the second product, Adhara, a propulsion bus for smaller satellites and craft that the company is focusing on keeping straightforward, compact and, of course, green. (It’s the smaller rig in the image above; the thrusters are named Lyla.)

“We’ve heard from customers that complete, turnkey systems are what they mostly want, rather than buying components from many vendors and doing all the systems integration themselves like the old-school satellite manufacturers have historically done,” Franks said. So that’s what Adhara is for: “Keep it simple, bolt it on there, let it maneuver where it needs to go.”

Engineering these engines was no cakewalk, naturally, but Tesseract wasn’t reinventing the wheel. The principles are very similar to traditional engines, so development costs weren’t ridiculous.

The company isn’t pretending these are the only solutions that make sense now. If you need to have the absolute lowest mass or volume dedicated to propulsion, or don’t really care if it takes a week or a year to get where you’re going, electric propulsion is still probably a better deal. And for major missions that require high delta-V and don’t mind dealing with the attendant dangers, hydrazine is still the way to go. But the market that’s growing the most is neither one of these, and Tesseract’s engines sit in a middle ground that’s efficient, compact and far less dangerous to work with.

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Google enables end-to-end encryption for Android’s default SMS/RCS app



Enlarge / If you and your chatting partner are both on Google Messages and both have RCS enabled, you’ll see these lock icons to show that encryption is on.


Google has announced that end-to-end encryption is rolling out to users of Google Messages, Android’s default SMS and RCS app. The feature has been in testing for months, and now it’s coming to everyone.

Encryption in Google Messages works only if both users are on the service. Both users must also be in a 1:1 chat (no group chats allowed), and they both must have RCS turned on. RCS was supposed to be a replacement for SMS—an on-by-default, carrier-driven text messaging standard. RCS was cooked up in 2008, and it adds 2008-level features to carrier messaging, like user presence, typing status, read receipts, and location sharing.

Text messaging used to be a cash cow for carriers, but with the advent of unlimited texting and the commoditization of carrier messaging, there’s no clear revenue motivation for carriers to release RCS. The result is that the RCS rollout has amounted to nothing but false promises and delays. The carriers nixed a joint venture called the “Cross-Carrier Messaging Initiative” in April, pretty much killing any hopes that RCS will ever hit SMS-like ubiquity. Apple executives have also indicated internally that they view easy messaging with Android as a threat to iOS ecosystem lock-in, so it would take a significant change of heart for Apple to support RCS.

The result is that Google is the biggest player that cares about RCS, and in 2019, the company started pushing its own carrier-independent RCS system. Users can dig into the Google Messages app settings and turn on “Chat features,” which refers to Google’s version of RCS. It works if both users have turned on the checkbox, but again, the original goal of a ubiquitous SMS replacement seems to have been lost. This makes Google RCS a bit like any other over-the-top messaging service—but tied to the slow and out-of-date RCS protocol. For instance, end-to-end encryption isn’t part of the RCS spec. Since it’s something Google is adding on top of RCS and it’s done in software, both users need to be on Google Messages. Other clients aren’t supported.

Google released a whitepaper detailing the feature’s implementation, and there aren’t too many surprises. The company uses the Signal protocol for encryption, just like Signal, Whatsapp, and Facebook Messenger. The Google Messages web app works fine since it still relies on an (encrypted) local connection to your phone to send messages. Encrypted messages on Wear OS are not supported yet but will be at some point (hopefully in time for that big revamp). Even though the message text is encrypted, third parties can still see metadata like sent and received phone numbers, timestamps, and approximate message sizes.

If you and your messaging partner have all the settings right, you’ll see lock icons next to the send button and the “message sent” status.

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Apple’s podcast subscriptions went live today—with a 30 percent cut



As previously announced in April, Apple has today launched its new Podcasts Subscriptions feature on iOS, iPadOS, and macOS. The system allows users to subscribe to podcasts (or groups of podcasts called Channels) for extra perks.

Perks can include early access to episodes, as well as ad-free listening. Some shows may offer bonus content for subscribers as well. You can subscribe to a podcast with just one button using Apple’s payment system.

Podcast creators can charge whatever they please, with the minimum subscription fee being $0.49 per month. Apple takes 30 percent of that amount for the first year, but if a subscriber remains active beyond 12 months, Apple switches to taking just 15 percent of that subscription fee.

Fortunately, Apple doesn’t have any rules against additional ways to monetize podcasts that offer these subscriptions, such as asking listeners to also back a Patreon.

When you subscribe to a podcast, its show page will have a “Subscriber Edition” label on it. You can also trial subscriptions to participating podcasts to see if they’re worth actually paying for. The length of time these trial subscriptions last varies, but it seems to usually be a few days or as long as a week.

Channels are basically podcast bundles curated by someone. Channels aren’t limited to podcasts using Apple’s new subscriptions offerings, though. When you follow more than one channel, a new “My Channels” section will appear in the Listen Now tab of the Podcasts app. Initiating a paid subscription to a channel gives you subscriber status with all its member podcasts.

Podcasts Subscriptions will be available in 170 countries and regions on devices running iOS 14.6, iPadOS 14.6, and macOS 11.4 or later.

Listing image by Apple

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Make way for Windows 11? Windows 10 end-of-life is October 2025



Enlarge / Please show your retired operating system the respect it deserves, with a proper Viking funeral.

A new Windows visual refresh, code-named Sun Valley. is on the way this summer. Until recently, we’ve assumed that this update would simply bring a new look for Windows 10 21H2—the major release of Windows 10 in the second half of 2021—but new information in the form of posted end-of-life (EOL) dates for Windows 10 and a leaked screenshot of something purporting to be “Windows 11 Pro” heavily imply that serious changes are on the way.

Windows 10 EOL in 2025

Rumors of Sun Valley being “Windows 11” have been circulating for months—but until recently, we didn’t put much stock in them. Windows 10 was intended to be Windows as a Service—a radical departure from the prior era of new, major Windows releases every three years or so. It seemed likely that Sun Valley’s “sweeping visual rejuvenation” would result in Windows 10 21H2 looking very different from Windows 10 21H1. Why fix what’s not broken?

The first strong indication that bigger things may be coming landed last week from a Microsoft-published EOL notice for Windows 10. “Windows 10 Home and Pro”—no codenames, no minor version numbers—is now listed as retiring on October 14, 2025. “Retiring” is a part of the Modern Lifecycle Policy and means that the retired product leaves support entirely; this does not follow the old Fixed Lifecycle Policy with “mainstream” and “extended” support. Retired is retired—hit the pasture.

As Windows Central points out, the retirement date isn’t entirely a new phenomenon—Microsoft initially launched the operating system with “mainstream support” through October 2020 and “extended support” through October 2025, the same five-/10-year-support period it provides for server and enterprise operating systems. What has changed is the way Microsoft talks about that end of support—there was no retirement date for Windows 10 as a whole shown on the home-and-pro life cycle page until recently.

There isn’t any real question about the end of life at this point—Microsoft has published it, and we have no reason to think it won’t happen. The interesting questions revolve around what comes next and when it will happen.

Windows 11 in 2021?

We’ve been seeing rumors about Sun Valley being a new Windows 11 for a few months—and until Microsoft posted a fresh EOL for Windows 10, we were skeptical. Windows 10 has been touted as “Windows as a Service” with no real expiration date for some time now, and there was no real reason to expect anything different.

The end-of-life date for Windows 10 as an entire operating system changes that—and it’s backed up by leaked screenshots of a Windows build claiming to be “Windows 11 Pro” which showed up today on Baidu. The new build is visually similar to the canceled Windows 10X, and its screenshots appear legitimate. (The Verge says it can “confirm they are genuine,” with no details as to how.)

What does a new version of Windows mean for me?

For now, it’s unclear what a new “Windows 11” means for end users—there are no guarantees that existing Windows 10 licenses will allow the use of Windows 11, let alone an in-place upgrade. We also have no concrete idea about when new releases of Windows 10 will cease, when the first Windows 11 will be available, or what costs will be.

We do have an educated guess or two, though—Microsoft’s generous upgrade policies from Windows 7 to Windows 10 (you can still upgrade for free today!) strongly imply a similar policy for 11, which Microsoft will presumably be keen to get users on. We also don’t expect under-the-hood changes as sweeping as the ones which took place between 7 and 10. In all likelihood, in-place upgrades will be available.

We’d also like to point out that the consumer support cycle for Windows 10 is short. For example, Windows 10 21H1—the most current build—is only supported through December 2022. That’s a roughly 18-month lifecycle, and there are no extended support policies for consumer Windows anymore. When it leaves support, you’re expected to upgrade to the next version if you want to continue getting support and bugfixes.

We may or may not see a Windows 10 21H2 or even a Windows 10 22H1. But we don’t expect to see a new Windows 10 build past 2023 at the latest since that would imply the need to support 10 past its October 2025 retirement date.

More details are on the way

If you find the lack of concrete detail here frustrating, you’re not alone. Fortunately, the wait won’t be long—Microsoft’s What’s Next for Windows digital event is coming June 24, and we expect plenty of screenshots, news, and more detailed upgrade guidance at that time.

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