For most of its time at Mars, the MAVEN spacecraft provided a relay for scientific data uplinked from NASA’s rovers and landers on the Martian surface. The relay allowed NASA to return significantly more data and imagery from rovers like Perseverance and Curiosity than would be possible through a direct-to-Earth radio connection.

With MAVEN out of the picture, NASA has four other orbiters it can use to provide this critical radio link. But officials aren’t sure how much longer they will last. Three of the four remaining relay orbiters are older than MAVEN, which played an outsized role in the relay network thanks to its higher orbit.

“Over the life of the mission, MAVEN supported more than 8 percent of all of our relay sessions planned by our rovers and landers, but it accounted for nearly 18 percent of all of the data returned, illustrating its usefulness when returning large data volumes,” said Tiffany Morgan, director of NASA’s Mars Exploration Program.

The network still has plenty of capacity to support the Perseverance and Curiosity rovers, with some minor caveats.

“We do have remaining assets, and those assets have adjusted the amount of data that they return, and the rovers have also adjusted their planning for how they connect to those assets,” Morgan said. “There is a slight delay on occasion, because we don’t have as many assets in view, to getting our science data back, and MAVEN was critical in returning science data versus operational data. But the Mars Relay Network is resilient enough at this point in time to accommodate, for the most part, the loss of MAVEN with the added delay.” //

jimlux Ars Tribunus Militum
12y
1,671

jlredford said:
It's interesting that they're able to use so many different orbiters to do this relay function. Interesting and resilient! It's great that it can handle dropouts like MAVEN. As the system gets upgraded, I hope they keep all this inter-operability to handle the next failure. The Mars Reconnaissance Orbiter is the main link these days, and it's now 20 years old, almost twice the age of MAVEN.

That’s because most of them (at least those launched after 2005) fly the JPL developed Electra software defined radio (they’re manufactured by L3, but the hardware design and the software is JPL). The landers also use Electra radios (or Electra Lite). MER was the first Mars lander to use relay ops with an orbiter to return data, and after a week or two, it had returned more data through the relay link than all previous Mars missions combined. It’s that effective (compared to basic X-band Direct to Earth at 8 kbps)

And as far as interoperability goes, that’s part of the Prox-1 standard from the Consultative Committee on Space Data Standards (ccsds.org) - most people flying a relay payload use it (as will the new Mars Telecom Network, and similar spacecraft planned for the Moon). 400 MHz UHF at Mars for now, but S-band is coming, as is Ka-band.

Jet Propulsion Laboratory and California Institute of Technology

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Katalyst Space Technologies must launch the Swift rescue mission by this summer.

This page lists various fan-made tools that can help calculations related to the gameplay of Kerbal Space Program. Unlike addons, they do not directly influence the game, as they are run separately.

Performing a transfer from an orbit of one body directly to an orbit of another one seems like serious business. A few guides published on the forums have a lot of maths and stuff, you may think this is too complicated to figure out.

Well, it is rocket science, but: it's not complicated.

In the basic orbiting tutorial, you were introduced to the concept of orbiting, and basic orbit stabilization, as well as an orbital table to help you along. Now, what if you want an orbit that isn't on that table? What if you want to have an orbit with a specific period? That's where these formulae come in.

In the basic orbiting tutorial, you were introduced to the concept of orbiting, and basic orbit stabilization, as well as an orbital table to help you along. Now, what if you want an orbit that isn't on that table? What if you want to have an orbit with a specific period? That's where these formulae come in.

The blue circle is Kerbin itself, the light blue circle around it is the top of the atmosphere. You can click+drag on the left of Kerbin to set periapsis, or on the right of Kerbin for apoapsis. You can also use the text boxes to enter altitudes and velocities numerically.

You need to specify two values in all: either altitudes of periapsis and apoapsis, velocities at periapsis and apoapsis, or both altitude and velocity at either periapsis or apoapsis. You select the values you want to enter with the Parameters menu, the remainder of the information will be computed from the values you put in. If you enter altitude and a velocity above escape velocity, it'll give you excess velocity at infinity. The apoapsis and periapsis textboxes are altitudes above mean sea level (AMSL), the text report below has both altitudes AMSL and distances from the center of Kerbin. Note that if you specify values that lead to an apoapsis lower than periapsis, the plotted orbit and contents of the text fields will be swapped automatically.

This online tool calculates delta-v and CommNet requirements in KSP (a video game, Kerbal Space Program). It helps KSP players plan and solve complex missions. Just like the game, these calculators are made to be interactive and visual to help new players quickly grasp the mechanics of rocket science.

How to Use: Simply select the body you wish to perform orbital synchronization calculations on from the drop-down list, then pick the resonance you wish to place your craft in. Example: If you wanted a 2:3 resonance, enter 2 into Numerator and 3 into Denominator.

The JUMPSEAT satellites loitered over the North Pole to spy on the Soviet Union. //

In a statement, the NRO called Jumpseat “the United States’ first-generation, highly elliptical orbit (HEO) signals-collection satellite.” //

The Soviet Union was the primary target for Jumpseat intelligence collections. The satellites flew in highly elliptical orbits ranging from a few hundred miles up to 24,000 miles (39,000 kilometers) above the Earth. The satellites’ flight paths were angled such that they reached apogee, the highest point of their orbits, over the far northern hemisphere. Satellites travel slowest at apogee, so the Jumpseat spacecraft loitered high over the Arctic, Russia, Canada, and Greenland for most of the 12 hours it took them to complete a loop around the Earth.

This trajectory gave the Jumpseat satellites persistent coverage over the Arctic and the Soviet Union, which first realized the utility of such an orbit. The Soviet government began launching communication and early-warning satellites into the same type of orbit a few years before the first Jumpseat mission launched in 1971. The Soviets called the orbit Molniya, the Russian word for lightning. //

The disclosure of the Jumpseat program follows the declassification of several other Cold War-era spy satellites. They include the CIA’s Corona series of photo reconnaissance satellites from the 1960s, which the government officially acknowledged 30 years later. The NRO declassified in 2011 two more optical spy satellite programs, codenamed Gambit and Hexagon, which launched from the 1960s through the 1980s. Most recently, the NRO revealed a naval surveillance program called Parcae in 2023.

Waiting in the darkness a few miles away from the launch pad, I glanced around at my surroundings before watching SpaceX’s Falcon 9 thunder into the sky. There were no throngs of space enthusiasts anxiously waiting for the rocket to light up the night. No line of photographers snapping photos. Just this reporter and two chipper retirees enjoying what a decade ago would have attracted far more attention.

Go to your local airport and you’ll probably find more people posted up at a plane-spotting park at the end of the runway. Still, a rocket launch is something special. On the same night that I watched the 94th launch of the year depart from Cape Canaveral, Orlando International Airport saw the same number of airplane departures in just three hours. //

The Falcon 9’s established failure rate is less than 1 percent, well short of any safety standard for commercial air travel but good enough to be the most successful orbital-class in history. Given the Falcon 9’s track record, SpaceX seems to have found a way to overcome the temptation for complacency. //

According to analyses by BryceTech, an engineering and space industry consulting firm, SpaceX has launched 86 percent of all the world’s payload mass over the 18 months from the beginning of 2024 through June 30 of this year.

That’s roughly 2.98 million kilograms of the approximately 3.46 million kilograms (3,281 of 3,819 tons) of satellite hardware and cargo that all the world’s rockets placed into orbit during that timeframe. //

But Starship’s arrival will come at the expense of the workhorse Falcon 9, which lacks the capacity to haul the next-gen Starlinks to orbit. “This year and next year I anticipate will be the highest Falcon launch rates that we will see,” said Stephanie Bednarek, SpaceX’s vice president of commercial sales, at an industry conference in July.

SpaceX is on pace for between 165 and 170 Falcon 9 launches this year, with 144 flights already in the books for 2025. Last year’s total for Falcon 9 and Falcon Heavy was 134 missions. SpaceX has not announced how many Falcon 9 and Falcon Heavy launches it plans for next year.

Starship is designed to be fully and rapidly reusable, eventually enabling multiple flights per day. But that’s still a long way off, and it’s unknown how many years it might take for Starship to surpass the Falcon 9’s proven launch tempo. //

Despite all of the newcomers, most satellite operators see a shortage of launch capacity on the commercial market. “The industry is likely to remain supply-constrained through the balance of the decade,” wrote Caleb Henry, director of research at the industry analysis firm Quilty Space. “That could pose a problem for some of the many large constellations on the horizon.”

United Launch Alliance’s Vulcan rocket, Rocket Lab’s Neutron, Stoke Space’s Nova, Relativity Space’s Terran R, and Firefly Aerospace and Northrop Grumman’s Eclipse are among the other rockets vying for a bite at the launch apple.

ESCAPADE’s path through space, relative to the Earth, has the peculiar shape of a kidney bean. In the world of astrodynamics, this is called a staging, or libration, orbit. It’s a way to keep the spacecraft on a stable trajectory to wait for the opportunity to go to Mars late next year.

“ESCAPADE has identified that this is the way that we want to fly, so we launch from Earth onto this kidney bean-shaped orbit,” said Jeff Parker, a mission designer from the Colorado-based company Advanced Space. “So, we can launch on virtually any day. What happens is that kidney bean just grows and shrinks based on how much time you need to spend in that orbit. So, we traverse that kidney bean and at the very end there’s a final little loop-the-loop that brings us down to Earth.”

That’s when the two ESCAPADE spacecraft, known as Blue and Gold, will pass a few hundred miles above our planet. At the right moment, on November 7 and 9 of next year, the satellites will fire their engines to set off for Mars.

An illustration of ESCAPADE’s trajectory to wait for the opportunity to go to Mars. Credit: UC-Berkeley
There are some tradeoffs with this unique staging orbit. It is riskier than the original plan of sending ESCAPADE straight to Mars. The satellites will be exposed to more radiation and will consume more of their fuel just to get to the red planet, eating into reserves originally set aside for science observations.

The satellites were built by Rocket Lab, which designed them with extra propulsion capacity in order to accommodate launches on a variety of different rockets. In the end, NASA “judged that the risk for the mission was acceptable, but it certainly is higher risk,” said Richard French, Rocket Lab’s vice president of business development and strategy.

The upside of the tradeoff is that it will demonstrate an “exciting and flexible way to get to Mars,” Lillis said. “In the future, if we’d like to send hundreds of spacecraft to Mars at once, it will be difficult to do that from just the launch pads we have on Earth within that month [of the interplanetary launch window]. We could potentially queue up spacecraft using the approach that ESCAPADE is pioneering.”

Nvidia recently made headlines by announcing that one of the companies it is partnering with, Starcloud, plans to build a 5-gigawatt orbital data center with “super-large solar and cooling panels approximately 4 kilometers in width and length.”

To put that into perspective, the eight main solar arrays on the International Space Station—the largest ever assembled in space, requiring many space shuttle launches and spacewalks—span about 100 meters and produce a maximum of about 240 kW. That’s about 0.005 percent of the power Starcloud intends to generate. //

However, it sounds a little more feasible if such an array could be assembled autonomously. And on Thursday morning, Starcloud, along with a new in-space assembly company, Rendezvous Robotics, announced an agreement to explore the use of modular, autonomous assembly to build Starcloud’s data centers.

Starlink not allowed in Myanmar, but scammers reportedly use it “on a huge scale.”. //

Octavus Ars Scholae Palatinae
19y
1,200

For those that don't know the details of the technology, both the space vehicle and ground terminal must know and accurately report their information in order for both sides to properly compensate for the Doppler effect.

This isn't fully true, the terminal needs to know the satellite's position and velocity but the satellite does not need to know the terminal's location. All the Doppler and time delay compensation happens on the ground side. The terminals transmitter compensates for Doppler and time delay so the signal at the satellite is at the correct frequency, otherwise different terminals would interfere with each other as they will not be frequency and time aligned at the satellite.
From the down link prospective the satellite broadcast to a spot/cell which corresponds to a location on Earth. The satellite does not compensation as even terminals within the same cell will require slightly different frequency shifts and time delay shifts, which the user terminal compensates for.
Now I don't work for Starlink but do work for one of their largest competitors and having the user terminal do all the compensation is by far the easiest method. Our terminals report to a server their GPS XYZ position so we still know where they are located, but for receiving a signal from them the terminals only need the satellite's positional information and the satellite only needs to know the spot ID.

One company, a California-based startup named Muon Space, is partnering with SpaceX to bring Starlink connectivity to low-Earth orbit. Muon announced Tuesday it will soon install Starlink terminals on its satellites, becoming the first commercial user, other than SpaceX itself, to use Starlink for in-flight connectivity in low-Earth orbit. //

Putting a single Starlink mini-laser terminal on a satellite would keep the spacecraft connected 70 to 80 percent of the time, according to Greg Smirin, Muon’s president. There would still be some downtime as the laser reconnects to different Starlink satellites, but Smirin said a pair of laser terminals would allow a satellite to reach 100 percent coverage. //

SpaceX’s mini-lasers are designed to achieve link speeds of 25Gbps at distances up to 2,500 miles (4,000 kilometers). These speeds will “open new business models” for satellite operators who can now rely on the same “Internet speed and responsiveness as cloud providers and telecom networks on the ground,” Muon said in a statement. //

Live video from space has historically been limited to human spaceflight missions or rocket-mounted cameras that operate for a short time.

One example of that is the dazzling live video beamed back to Earth, through Starlink, from SpaceX’s Starship rockets. The laser terminals on Starship operate through the extreme heat of reentry, returning streaming video as plasma envelops the vehicle. This environment routinely causes radio blackouts for other spacecraft as they reenter the atmosphere. With optical links, that’s no longer a problem.

“This starts to enable a whole new category of capabilities, much the same way as when terrestrial computers went from dial-up to broadband,” Smirin said. “You knew what it could do, but we blew through bulletin boards very quickly to many different applications.”

Two Falcon 9 rockets lifted off from spaceports in Florida and California on Sunday afternoon, adding 56 more satellites to SpaceX’s Starlink broadband network.

The second of these two launches—originating from Vandenberg Space Force Base, California—propelled SpaceX’s Starlink program past a notable milestone. With the satellites added to the constellation Sunday, the company has delivered more than 10,000 mass-produced Starlink spacecraft to low-Earth orbit.

The exact figure stands at 10,006 satellites, according to a tabulation by Jonathan McDowell, //

The Starlink network surpassed 7 million global subscribers in August, primarily beaming Internet connectivity to homes and businesses. SpaceX is now aggressively pushing to broaden its service direct to smartphones. //

SpaceX is decommissioning aging and obsolete Starlink satellites as the company adds to the fleet. The retired satellites reenter the atmosphere, where they’re designed to burn up without any debris reaching the ground. Taking into account all the reentries, here are McDowell’s numbers for the Starlink fleet as it stands Monday, October 20:

8,680 total Starlink satellites in orbit
8,664 functioning Starlink satellites in orbit (including newly launched satellites not yet operational)
7,448 Starlink satellites in operational orbit //

Sunday’s SpaceX launches weren’t just noteworthy for Starlink. The first of the two missions, departing from Florida’s Space Coast, marked the 31st launch of the company’s most-flown Falcon 9 booster. The rocket landed on SpaceX’s recovery ship in the Atlantic Ocean to be returned to Florida for a 32nd flight. //

SpaceX engineers are now certifying the Falcon 9 boosters for up to 40 flights apiece.

The season of records isn’t over. SpaceX is expected to set another one later this week. The company’s launch log for 2025 currently stands at 132 Falcon 9 missions, tying the total number of Falcon 9 flights last year. SpaceX also launched two flights of the more powerful Falcon Heavy in 2024, bringing the 2024 mark to 134 missions by the Falcon rocket family.

A new listing of the 50 most concerning pieces of space debris in low-Earth orbit is dominated by relics more than a quarter-century old, primarily dead rockets left to hurtle through space at the end of their missions. //

Russia and the Soviet Union lead the pack with 34 objects listed in McKnight's Top 50, followed by China with 10, the United States with three, Europe with two, and Japan with one. Russia's SL-16 and SL-8 rockets are the worst offenders, combining to take 30 of the Top 50 slots. //

The list published Friday is an update to a paper authored by McKnight in 2020. This year's list goes a step further by analyzing the overall effect on debris risk if some or all of the worst offenders were removed. If someone sent missions to retrieve all 50 of the objects, the overall debris-generating potential in low-Earth orbit would be reduced by 50 percent, according to McKnight. If just the Top 10 were removed, the risk would be cut by 30 percent. //

China, on the other hand, frequently abandons upper stages in orbit. China launched 21 of the 26 hazardous new rocket bodies over the last 21 months, each averaging more than 4 metric tons (8,800 pounds). Two more came from US launchers, one from Russia, one from India, and one from Iran. //

Since 2000, China has accumulated more dead rocket mass in long-lived orbits than the rest of the world combined, according to McKnight. "But now we're at a point where it's actually kind of accelerating in the last two years as these constellations are getting deployed."

Launched in 1975, the probe outlived its 90-day mission by years and set the standard for Mars landings //

It's been 50 years since NASA sent Viking 1 on a mission to Mars.

Launched on a Titan-Centaur rocket from Complex 41 at Cape Canaveral Air Force Station on August 20, 1975, Viking 1 was one of a pair of probes sent to land on Mars.

Viking 1 consisted of an orbiter and a lander and followed earlier US missions to Mars that had begun with Mariner 4 in 1964, continuing with the Mariner 6 and 7 flybys, and the Mariner 9 Mars orbital mission. //

The Viking 1 spacecraft arrived in orbit around Mars on June 19, 1976.

Power came from a pair of 35 W radioisotope thermoelectric generators (RTGs), connected in series on top of the lander. According to NASA [PDF], "the computer was one of the greatest technical challenges of Viking." There were two general-purpose computer channels, each with a storage capacity of 18,000 words. One was active while the other was in reserve. There was also a tape recorder.

Viking 1 was an unparalleled success. The orbiter and lander lasted far longer than initial expectations. The orbiter was eventually shut down in August 1980 after it ran out of attitude control propellant. It had begun to run low in 1978, but engineers were able to eke it out for a further two years. The lander kept on going until its final transmission on November 11, 1982.

Unfortunately, the lander's failure wasn't due to its hardware or the harsh environment of Mars. It was instead "a faulty command sent from Earth," according to NASA. The command resulted in loss of communication. Controllers spent the next six and a half months attempting to regain contact with the lander before the overall mission came to an end on May 21, 1983.

It is debatable how much longer the lander could have lasted. Viking 2's lander transmitted data until April 12, 1980, but its batteries eventually failed. Both landers and their respective orbiters had operated far beyond their planned mission lifetimes.

Black Hat Four countries have now tested anti-satellite missiles (the US, China, Russia, and India), but it's much easier and cheaper just to hack them.

In a briefing at the Black Hat conference in Las Vegas, Milenko Starcik and Andrzej Olchawa from German biz VisionSpace Technologies demonstrated how easy it is by exploiting software vulnerabilities in the software used in the satellites themselves, as well as the ground stations that control them.

"I used to work at the European Space Agency on ground station IT and got sick of telling them what was wrong and not having them fix it," Olchawa told The Register, "So I decided to go into business to do it myself." //

"We found actual vulnerabilities which allow you to crash the entire onboard software with an unauthenticated telephone," claimed Starcik.

"So basically, you send a packet to the spacecraft, and the entire software crashes and reboots, which then actually causes the spacecraft, if it's not properly configured, to reset all its keys. And then you have zero keys on the spacecraft that you can use from that stage on."