SpaceX engineers also reveal machine learning is not used on the Dragon and Falcon spacecraft. //

Each of SpaceX's monthly launches of 60 internet-beaming Starlink satellites carries 4,000 stripped-back Linux computers, SpaceX software engineers have revealed.

SpaceX engineers disclosed the detail in a Reddit Ask Me Anything (AMA) session over the weekend. //

It also means that it's now sent 32,000 Linux computers to space for the existing constellation.

"The constellation has more than 30,000 Linux nodes (and more than 6,000 microcontrollers) in space right now," wrote Matt Monson, SpaceX's director of Starlink software.

"And because we share a lot of our Linux platform infrastructure with Falcon and Dragon, they get the benefit of our more than 180 vehicle-years of on-orbit test time." //

We designed the system to use end-to-end encryption for our users' data, to make breaking into a satellite or gateway less useful to an attacker who wants to intercept communications," wrote Moran.

"Every piece of hardware in our system (satellites, gateways, user terminals) is designed to only run software signed by us, so that even if an attacker breaks in, they won't be able to gain a permanent foothold.

"And then we harden the insides of the system (including services in our data centers) to make it harder for an exploited vulnerability in one area to be leveraged somewhere else. We're continuing to work hard to ensure our overall system is properly hardened, and still have a lot of work ahead of us (we're hiring), but it's something we take very seriously."

Click on satellites for more information about them. Click and drag to rotate the view.

All magnitudes and sky positions are shown for Texarkana. Change location.

Ahead of the latest Falcon 9 mission, SpaceX has conducted six launches of the operational Starlink v1.0 design, for a total of 360 satellites.

With SpaceX planning to launch another set of Starlink internet satellites on Wednesday, the company will continue the deployment of the initial constellation of approximately 1500 satellites, on the way to building their 4400 satellite Ku-/Ka-band network. //

A handful of these suffered problems on orbit, with three being actively deorbited so far and SpaceX noting in an FCC filing that six more have had propulsion problems after they began orbit raising. The current number of functional Starlink satellites for providing service to customers is around 350, not all of which have reached their operational position yet.

Each launch of 60 satellites that have been carried so far has aimed to populate three planes of 20 satellites, each plane spaced 20 degrees apart at the equator. Once they get 18 evenly spaced planes into position, they should be able to test the system with continuous service in the northern United States.

As it takes about four months for the satellites to all reach their operational positions from launch, it appears SpaceX decided to speed up the process a little by using the seventh launch on June 3 to populate the 18th plane.

Moving forward, subsequent launches will be used to create more planes in between the existing ones until there are 72 planes spaced five degrees apart.

A handful of these suffered problems on orbit, with three being actively deorbited so far and SpaceX noting in an FCC filing that six more have had propulsion problems after they began orbit raising. //

Going forward, U.S. space exploration will be mostly done by the private sector, that is, if we wish to retain our lead @teamcavuto //

Cavuto had to throw cold water on the excitement. With no less than 5 of his guests, he insisted on asking, “What do you think about private companies taking the lead in space flight?” His tone and tenor implied that this was a bad thing—something wrong. //

Well, Mr. Cavuto, private enterprise has been at the forefront of aviation since its beginnings here in these United States. When the Wright Brothers took their famous flight, they were not employees of the Federal Government. Robert Goddard, long looked at as one of the pioneers of American rocketry, was a private citizen, funded mostly by private organizations. Throughout the rise of first aviation and then rocketry, private citizens, either alone or in private companies, were leading the charge on new discoveries and technological innovation.

One major exception to this, was when NACA/NASA was given the mission to beat the Soviets into space and thence to the Moon. Indeed, many of the researchers and designers were federal employees. But that was a crash program and itself an aberration. //

One tool that enabled this private sector innovation was the use of prize money or private sponsorships. In aviation, prize money, either from private donations or even sometimes from government, was quite commonly used to incentivize the private sector to solve a technological problem. Here is a clip from the December 1947 issue of Flying Magazine. Note the public-private partnership and use of prize money. //

Our education system is sadly failing our citizens. The fact that one of the lead anchors on an allegedly center-right news organization looks at a privately-led exploration effort in space and considers that not only some sort of aberration, but implies that there is something wrong with it, bothers me. It’s an insult to explorers and innovators like Drake, Cook, Shackleton, Goddard, Frank, and Orville Wright, to name but a few. Mr. Cavuto, it’s NASA that is the aberration, not Space-X.

SpaceX's internet connectivity constellation is forming, and it looks set to make a big impact.

Scott Tilley, a Canadian ham radio enthusiast, used his spare time during COVID-19 lockdown to track down a signal from LES-5, an experimental communications satellite launched in 1967.

Operating a mission is a labyrinthian process from start to finish, with all kinds of checks and fail-safes along the way.

SpaceX CEO and founder Elon Musk has shared more details about when in 2020 we can expect the company’s Starlink low-latency, high-bandwidth satellite internet service to actually be available to customers. He said on Twitter that a private beta for Starlink would begin in around three months…

As SpaceX continues its steady march of Starlink internet satellite launches, the company reaches... //

The seventh flight of Starlink satellites is set to launch Wednesday, 22 April at 15:30 EDT (19:30 UTC) from LC-39A at the Kennedy Space Center.

The U.S.’s most flown, active rocket:

This flight marks a major point in U.S. launch operations, as Falcon 9 reaches 84 flights to its name and officially takes the mantle from Atlas V as the most flown, currently operational U.S. rocket.

Atlas V began flying on 21 August 2002 and has 83 flights to its name after 18 years — for an annual rate of 4.6 launches.

Falcon 9 began flying on 4 June 2010 and will reach 84 flights in just under 10 years with a flight rate of 8.4 launches per year. //

The changing of the guard — so to speak — is made all the more impressive by the fact that in its first three years, Falcon 9 only flew five times.

By June 2015, the rocket had 19 flights to its name — 14 flights in two years compared to 5 flights in the first three years.

In the second five years of operation, Falcon 9 amassed an impressive 65 flights (counting the seventh flight of Starlink on Wednesday) — an average of 13 missions a year. //

Moreover, the impressive rise of Falcon 9 occurred while SpaceX actively redesigned — in some cases, radically — the rocket through numerous changes, culminating more or less in the Block 5 design flying today.

Meanwhile, the company implemented reusability with the Falcon 9 to a scale that sent U.S. and global competitors scrambling to design lower-cost and/or reusable rocket systems. //

With the seventh flight of Starlink on Wednesday, SpaceX will make its 92nd orbital launch attempt.

At this rate, the company will likely achieve its 100th orbital launch attempt in the summer or autumn months this year.

NASA has selected two cubesat missions to launch as part of the Artemis project to return humans to the moon.

Northrop says this is a first step toward a fleet of satellite-servicing vehicles. //

On Tuesday, a spacecraft that was launched four months earlier docked with a communications satellite about 36,000km above the Earth. Northrop Grumman reported the historic docking on Wednesday, and the company heralded the mission as an "historic accomplishment" in the field of satellite servicing. Prior to this mission, no two commercial spacecraft had ever docked in orbit before.

Launched on a Proton rocket in October, the Mission Extension Vehicle-1 (MEV-1) has a fairly long history of development under various companies. Ultimately, it was brought to space by SpaceLogistics, a wholly owned subsidiary of Northrop Grumman. After the company's rideshare launch in October, its MEV-1 spacecraft used electric-propulsion thrusters to raise its orbit 290km above geosynchronous orbit. //

a communications satellite launched in 2001 (Intelsat-901) was pulled from active service in December 2019 as it ran low on fuel. Operators commanded the satellite to move into a "graveyard orbit" above geostationary space. It is here that MEV-1 linked up with the communications satellite on Tuesday.

According to Northrop Grumman, the combined spacecraft stack will now perform on-orbit checkouts before MEV-1 starts to relocate the combined vehicle back into geostationary orbit, where Intelsat 901 will continue in service for five additional years. //

Northrop says its MEV-1 spacecraft uses a mechanical docking system that attaches to existing features on a satellite, and it is designed for multiple docking and undockings and can deliver over 15 years of life-extension services. The company plans to launch its second Mission Extension Vehicle, MEV-2, later this year. Northrop also said this is its first step toward establishing a fleet of satellite servicing vehicles that not only extend the life of satellites but provide inclination changes and spacecraft inspections and perform in-orbit repair and assembly. ///

This design has been on paper for several decades, but kept getting killed by company execs who didn't want to kill their cash cow of building and launching new satellites. Northrop Grumman doesn't have a big satellite manufacturing or launch business, but now they have the potential for a satellite refueling and repair business....

Featured Image Source: SpaceX SpaceX plans to fund future missions to the moon and Mars by offering Starlink internet services. SpaceX officials stated that Starlink broadband internet network will be affordable enough that areas in the world where internet is non-existent, or unreliable will benefit from their service

The Spitzer Space Telescope lasted over 16 years //

Spitzer is one of four space telescopes operated by NASA known as the Great Observatories. Its fellow “greats” are the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the famous Hubble Space Telescope. Combined, the four telescopes were meant to observe the Universe in as many wavelengths of light as possible — ranging from the visible light that we can see, to the kinds of light our eyes cannot register. Spitzer’s charge has been to observe infrared light, a type of light that humans can’t see but can sense as heat. Objects that are faint and super cold can still be seen by the infrared light that they produce, so Spitzer can show us things that might otherwise seem invisible. //

This afternoon, NASA scientists will send a command to Spitzer, telling it to stop taking observations and no longer send pings back to Earth. Conceivably, NASA could wake Spitzer back up again someday, but as more time passes, the tougher that will be. Spitzer will no longer be pointing its antenna back at Earth and sending a strong signal that NASA can pick up. So making a link with the spacecraft will become harder and harder.

But even as Spitzer hangs up its hat, there are still other infrared telescopes in the works — notably, NASA’s next great space observatory, the James Webb Space Telescope. Designed to study the Universe in infrared, the James Webb will be the most powerful space telescope ever when it launches, and will be able see back in time to the beginning of the Universe. //

Is Russia checking out one of our assets?

A 1970 law could throw a major wrench in SpaceX's plans. //

Ramon Ryan, law student at Vanderbilt University, argues in a yet to be published paper that the Federal Communications Commission’s (FCC) approval for the project might have been unlawful, Scientific American reports.

“There is this law, the National Environmental Policy Act [NEPA], which requires federal agencies to take a hard look at their actions,” Ryan told the Scientific American. “The FCC’s lack of review of these commercial satellite projects violates [NEPA], so in the most basic sense, it would be unlawful.”

NEPA was introduced in 1970 to force all federal agencies to take the environmental toll, covering anything from wildlife preservation to the effects on climate, of projects into account — a requirement that can be skirted with a special “categorical exclusion” if there’s proof a certain project doesn’t impact the environment.

The FCC was granted such an exclusion for almost all of its activities, including in space, in 1986.

Ryan argues that such an exclusion would never hold up in court.

“If the FCC were sued over its noncompliance with NEPA, it would likely lose,” Ryan told the Scientific American, as the agency has never actually been able to prove that commercial satellites don’t impact the environment.

Becoming a satellite operator has not been without its challenges.

SpaceX performed a hold-down test-firing of the Falcon 9’s first stage Merlin engines Friday. The test-firing is a customary pre-launch checkout before every SpaceX mission, providing a test of launch vehicle systems and a rehearsal for the company’s launch team.

The Falcon 9 was raised vertical at pad 40 without its satellite payload or fairing Friday in preparation for the static fire test. SpaceX loaded super-chilled, densified kerosene and liquid oxygen propellants into the two-stage Falcon 9 rocket, and the countdown proceeded through through the final steps before launch, including retraction of the strongback structure into position for liftoff and pressurization of the rocket’s propellant tanks. //

The nine Merlin 1D engines at the bottom of the Falcon 9’s first stage ignited for several seconds at 1:20 p.m. EST (1820 GMT) Friday, throttling up to full power to generate some 1.7 million pounds of thrust as hold-down restraints keep the rocket firmly on the ground.

SpaceX engineers will perform a data review after the static fire as technicians at Cape Canaveral roll the rocket back to the hangar and prepare to mate it with the JCSAT 18/Kacific 1 communications satellite inside a climate-controller hangar.//

The Falcon 9 rocket slated to launch the JCSAT 18/Kacific 1 spacecraft is a veteran of two previous missions. It first launched in May on a space station cargo mission, then landed on SpaceX’s drone ship in the Atlantic Ocean. On its second flight, the rocket again powered a Dragon supply ship toward the space station, and returned to Cape Canaveral for an onshore landing.

SpaceX is expected to recover the first stage again after Monday’s launch aboard a drone ship in the Atlantic east of Florida’s Space Coast.

The 15,335-pound (6,956-kilogram) JCSAT 18/Kacific 1 spacecraft will launch into an elliptical transfer orbit, then use its on-board liquid-fueled engine to maneuver into a circular geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) over the equator.

Starlink has had its fair share of critics in the last few months. The ambitious SpaceX project to launch up to 42,000 satellites and provide worldwide internet access has the International Astronomical Union, scientists, and stargazers nervous about

SpaceX launched 60 Starlink satellites into orbit on its most flown Falcon 9 rocket yet, which made a historic fourth launch and landing on Monday (Nov. 11).

The Catalog

I have compiled a catalog of over 1000 artificial objects in `deep space'. Version 1.0 of this catalog has been released online at https://planet4589.org/space/deepcat.

By deep space, I mean broadly space beyond the region where the US satellite catalog provides coverage. Note that the term has been used with a variety of definitions. In the context of the SGP4 orbit model [3], deep space' refers to orbital periods above 225 minutes, corresponding to altitudes of about 5900 km, a region normally thought of asmedium Earth orbit' these days. For our purposes a boundary somewhere beyond 50,000 km seems needed. It also appears desirable to exclude communications satellites on supersynchronous transfer orbits which have apogees typically in the 60,000 to 100,000 km range.

For definiteness I adopt a boundary I call [14] EL1:4, the Earth-lunar 1 to 4 orbit resonance in which a satellite in a circular orbit will complete four revolutions of the Earth for every one that the Moon does. EL1:4 is at 152066 km from Earth's center. The choice is motivated by the idea that satellites well within this distance can to first order ignore the Moon and be regarded as being in simple Keplerian orbits on short timescales (clearly, even much closer in at GEO, lunisolar perturbations are important on longer timescales). Satellites at this distance or beyond are more strongly affected by lunar perturbations and should be considered as part of a three-body system. This distinction is obviously not a sharp one and is somewhat arbitrary but it seems as good as any. It also echoes the Sun-Jupiter 1 to 4 resonance which approximately marks the inner edge of the asteroid belt and which serves as a good candidate for a boundary between the inner and outer solar system.