NASA briefly loses contact with the ISS

[OneHungLow]

Somewhat embarrassing when you have to rely on your arch enemy for comms methinks!

A power outage at Nasa’s building in Houston disrupted communication between mission control and the International Space Station (ISS) on Tuesday, forcing the space agency to rely on backup control systems for the first time.

The outage meant mission control lost command, telemetry and voice communications with the station in orbit. The power outage hit as upgrade work was under way in the building at Houston’s Johnson Space Center.

The crew was notified of the problem through Russian communication systems, within 20 minutes of the outage.

Space station program manager Joel Montalbano said neither the astronauts nor station were ever in any danger and that backup control systems took over to restore normal communications within 90 minutes. “It wasn’t an issue on board. That was purely a ground problem,” he said. “At no time was the crew or the vehicle in any danger.”

“We knew this work was going on, and in preparation for that we have the backup command and control system that we would use if we have to close the centre for weather emergency, especially important during the hurricane season,” he said.

It is the first time Nasa has had to fire up these backup systems to take control, according to Montalbano. He said Nasa hoped to resolve the issue and be back to normal operations by the end of the day.

Nasa maintains a backup control centre miles from Houston in the event of a disaster requiring evacuations. But in Tuesday’s case, the flight controllers stayed at mission control since the lights and air-conditioning still worked.

“We’ll better understand what happened and then take lessons learned and move forward,” Montalbano said.

The tensions between the US and Russia on Earth do not prevent their respective space agencies from working together, although Moscow has said it will withdraw from the ISS after 2024 and build its own station instead. In February, Moscow launched a rescue vessel to the ISS to bring home three crew stranded after their original capsule was hit by a meteoroid.

Last year, cosmonauts arrived at the ISS wearing yellow flight suits with blue accents, colours that match the Ukrainian flag, shortly after Russia’s invasion began. The message, if any was intended, was unclear. Months later, Russia’s space agency published photos appearing to show cosmonauts on the ISS holding the flags of the self-proclaimed republics in Luhansk and Donetsk.

https://www.theguardian.com/science/202 ... up-systems

[OneHungLow]

Woops!

Nasa engineers hope to re-establish contact with the Voyager 2 spacecraft after sending a faulty command that severed communications with the far-flung probe.

The spacecraft is one of a pair that launched in 1977 to capture images of Jupiter and Saturn, but continued on a journey into interstellar space to become the farthest human-made objects from Earth.

The space agency lost contact with Voyager 2, which is now more than 12bn miles away, when mission staff accidentally beamed the wrong command to the distant spacecraft more than a week ago.

The command caused the probe to tilt its antenna away from Earth, and although the direction it is pointing in changed by only 2%, the shift was enough for engineers operating receivers on Earth to lose touch with it.

Voyager 2 and its twin, Voyager 1, were launched within a couple of weeks of one another to explore the planets and moons of the outer solar system. Voyager 1 is still in contact with Earth and nearly 15bn miles away. In 2012, it became the first probe to enter interstellar space and is now the most distant spacecraft ever built.

Voyager 2 hurtled into interstellar space in 2018 after discovering a new moon around Jupiter, 10 moons around Uranus and five around Neptune. It remains the only spacecraft to study all four of the solar system’s giant planets at close range.

The next hope of making contact with the spacecraft will come this week when the Canberra dish, part of Nasa’s deep space network, beams the correct command in the direction of Voyager 2 in the hope of reaching the probe’s antenna, according to the space agency’s Jet Propulsion Laboratory in Pasadena, California.

The spacecraft is so far away that even at the speed of light, software commands sent from Earth take 18 hours to reach the probe.

Nasa concedes that the attempt to make contact through the huge dish antenna in Canberra is a long shot. If that effort comes to nothing, as engineers expect, mission controllers will have to wait until October when the spacecraft should reset automatically and restore communications.

The Voyager probes have faced numerous glitches in more than 40 years in space. Voyager 1 was still en route to Jupiter when it wrongly switched to a backup radio receiver, only to have the primary receiver burn out when engineers switched it back. After its fly-by of Saturn, Voyager 2’s camera platform got stuck because of a lack of lubricant. Much later, in 2010, the probe suffered a glitch that temporarily affected its science data.

Keeping the probes flying became an art as much as a science after many engineers moved on to other Nasa missions, leaving a dwindling number of ageing staff familiar with the probe and its software. Though state-of-the art in the 1970s, the Voyager spacecraft have only four kilobytes of storage onboard and computing power thousands of times slower than a modern smartphone.

The spacecraft entered interstellar space after leaving what astronomers call the heliosphere – a protective bubble of particles and magnetic fields that are created by the sun. But neither Voyager probe has yet left the solar system. The edge of the solar system is beyond the Oort cloud where smaller cosmic bodies are still under the influence of the sun’s gravitational pull. Nasa estimates that it could take 300 years for Voyager 2 to reach the Oort cloud and perhaps 30,000 years to cross it.

https://www.theguardian.com/science/202 ... ng-command

[PHXPhlyer]

NASA hears ‘heartbeat’ of Voyager 2 after losing communication

https://www.cnn.com/2023/08/01/world/vo ... index.html

The Voyager mission team at NASA has been able to detect a signal from Voyager 2 after losing contact with the spacecraft, which has been operating for nearly 46 years.

“We enlisted the help of the (Deep Space Network) and Radio Science groups to help to see if we could hear a signal from Voyager 2,” said Suzanne Dodd, Voyager’s project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “This was successful in that we see the ‘heartbeat’ signal from the spacecraft. So, we know the spacecraft is alive and operating. This buoyed our spirits.”

Commands sent to Voyager 2 on July 21 accidentally caused the spacecraft’s antenna to point 2 degrees away from Earth. The miniscule shift means that Voyager 2 can’t receive any commands from mission control or send data back to Earth from its location more than 12.3 billion miles (19.9 billion kilometers) in interstellar space.

The mission team was pleasantly surprised to be able to detect the spacecraft’s “carrier signal” using the Deep Space Network, an international array of massive radio antennas that allows NASA to communicate with missions across the cosmos.

Each of the three giant dishes are equidistant, meaning that one is always in communication with different spacecraft as Earth rotates. One radio antenna is located at Goldstone near Barstow, California, the second near Madrid, and the third near Canberra, Australia.

Now, the mission team will attempt to send a signal back to the spacecraft.

“We are now generating a new command to attempt to point the spacecraft antenna toward Earth,” Dodd said. “There is a low probability that this will work.”

‘Shouting’ into the cosmos
The signal, sent via the Deep Space Network, is basically an attempt to “shout” at Voyager 2 and try to get its attention, despite the fact that its antenna isn’t oriented in a way to receive the radio signal, according to NASA.

Given the distance between Voyager 2 and Earth, it takes about 18.5 hours for the signal to travel one way across the solar system to the spacecraft.

If the Earth-based signals don’t reach Voyager 2, the spacecraft is already programmed to reorient itself multiple times a year to keep its antenna pointing in Earth’s direction. The next reset was already scheduled for October 15, and the team is hopeful that this program will allow communications to resume with Voyager 2.

“But that is a long time to wait, so (we) will try sending up commands several times prior to that date,” Dodd said.

It’s not the first time that the aging twin probes, both launched in 1977, have experienced issues. As these “senior citizens” continue exploring the cosmos, the team has slowly turned off instruments to conserve power and extend their missions. Along the way, both Voyager 1 and 2 have encountered unexpected issues and dropouts, including a seven-month period where Voyager 2 and the Deep Space Network couldn’t communicate in 2020.

The team expects that Voyager 2 will remain on its planned trajectory, even without receiving commands. Meanwhile, Voyager 1, which is nearly 15 billion miles (24 billion kilometers) from Earth, continues to operate as expected and communicate with the Deep Space Network.

Both are in interstellar space and the only spacecraft to operate beyond the heliosphere, the sun’s bubble of magnetic fields and particles that extends well beyond the orbit of Pluto, collecting valuable data as they explore uncharted interstellar territory.

PP

[OneHungLow]

NASA hears ‘heartbeat’ of Voyager 2 after losing communication

https://www.cnn.com/2023/08/01/world/vo ... index.html

The Voyager mission team at NASA has been able to detect a signal from Voyager 2 after losing contact with the spacecraft, which has been operating for nearly 46 years.

PP

The silence is no sooner spoken than broken! Good news PHX!

[OFSO]

Two incidents from my own experience, both NASA.
- Shortly after putting a spacecraft into orbit, a witless spacecraft controller sent a "battery disconnect" command. Never heard what happened to him.
- Another three-axis-stabilised spacecraft was lost because the wrong size fuses (think about that) were installed in the power feed from the solar array. Fuses? Really?

[Fox3WheresMyBanana]

Mars Climate Orbiter, 1999, burned up in the Martian atmosphere.
A Lockheed Martin module produced commands in US units (contrary to spec), whilst subsequent modules expected commands in SI units.
NASA blamed itself for its check procedures failing to spot the error. Commands were in error by a factor of 4-ish.
The effect of the erroneous commands was detected by at least two mission navigators, but their concerns were dismissed by higher management because they hadn't filled the right form in.
I'd like to report that higher management were taken out and shot with anti-aircraft cannon (a Yung Fat Wun favourite, that), but they weren't even moved out of post.
And there were at least three more major errors in check procedures that could have detected the error.
In fact, every single check procedure failed.

More detail here
https://spectrum.ieee.org/why-the-mars- ... off-course

..and if you think this kind of thing can't happen today, I have several stories about building fire procedures to relate...

banging-head-against-brick-wall.gif (1.78 KiB) Viewed 1646 times

Essentially, non-technical management generate check procedures to cover their asses and agree with their decisions. If they fail to do either of these, due to some freak of reality (Oh, The Horror!), they are ignored....and even more procedures that fit the same conditions are generated. So one ends up with a plethora of check procedures, all of which are ignored if they don't give the answer management wanted to hear. And of course at vast expense and delay.
Obviously, absolutely none of the above applies to Covid actions, Inflation, Climate Change policies, etc, etc,

[OneHungLow]

What amazes me is that radio signals from earth can traverse +12.3 billion miles and that that signal is not swamped by the radio noise of the cosmos. That the both Voyager spacecraft can still send signals back to the earth is truly awe inspiring.

This article on the Voyager 1 signal strength gives some idea of weak the signal is when it reaches earth.

It is worth starting with AASC, which stands for the Articulation and Control Relationship System, designed to send data about Voyager’s position in space and its course of flight back to Earth. High-gain AASC antenna is permanently directed toward our planet to help amplify the weak wave signal emanating from the probe in space.

As Voyager’s signal strength gradually moves away from Earth, it continually decreases, causing the data rate from the probe to our planet to decrease. As of 2017, the probe’s signal strength was approximately -160.48 dBm, which is about 1,000 times weaker than the signal of a conventional FM receiver. Nevertheless, modern technology has significantly improved the sensitivity of the receiving antenna network. Even 44 years later, NASA can both pick up weak radio fluctuations coming from Voyager 1 and send it a response with a much higher signal strength from Earth.

Surprisingly, Voyager uses low-power radio receivers with a capacity of 23 watts to get the signal at such a long range. The receiving antenna on the spacecraft has a diameter of 3.7 meters, while the receiving antennas on Earth that form the Deep Space Network have a diameter of 34 and 70 meters.

https://maxpolyakov.com/the-mystery-of- ... eep-space/

[llondel]

Impressive path loss at that distance, of the order of 200dB, depending on the gain of the antennas at each end.

[PHXPhlyer]

NASA restores contact with Voyager 2 spacecraft after mistake led to weeks of silence
Voyager 2 has been hurtling through space since its launch in 1977 to explore the outer solar system.

https://www.nbcnews.com/science/space/n ... -rcna98281

CAPE CANAVERAL, Fla. — NASA’s Voyager 2 spacecraft was back chatting it up Friday after flight controllers corrected a mistake that had led to weeks of silence.

Hurtling ever deeper into interstellar space billions of miles away, Voyager 2 stopped communicating two weeks ago. Controllers sent the wrong command to the 46-year-old spacecraft and tilted its antenna away from Earth.

On Wednesday, NASA’s Deep Space Network sent a new command in hopes of repointing the antenna, using the highest powered transmitter at the huge radio dish antenna in Australia. Voyager 2’s antenna needed to be shifted a mere 2 degrees.

ASA's Voyager 2 probe has signaled it is in "good health" after mission control mistakenly cut contact for several days, the space agency said in its latest update. Launched in 1977 as a beacon from humanity to the wider Universe, it is currently more than 12.3 billion miles (19.9 billion kilometers) from our planet, exploring interstellar space along with its twin, Voyager 1. A series of planned commands sent to Voyager 2 on July 21, 2023, "inadvertently caused the antenna to point two degrees away from Earth," NASA's Jet Propulsion Laboratory (JPL) said in a recent update.

It took more than 18 hours for the command to reach Voyager 2 — more than 12 billion miles (19 billion kilometers) away — and another 18 hours to hear back.

The long shot paid off. On Friday, the spacecraft started returning data again, according to officials at California’s Jet Propulsion Laboratory.

“I just sort of sighed. I melted in the chair,” project manager Suzanne Dodd told The Associated Press.

“Voyager’s back,” project scientist Linda Spilker chimed in.

Voyager 2 has been hurtling through space since its launch in 1977 to explore the outer solar system. Launched two weeks later, its twin, Voyager 1, is now the most distant spacecraft — 15 billion miles (24 billion kilometers) away — and still in contact.

The two-week outage was believed to be the longest NASA had gone without hearing from Voyager 2, Dodd said.

As long as their plutonium power holds, the Voyagers may be alive and well for the 50th anniversary of their launch in 2027, according to Dodd. Among the scientific tidbits they’ve beamed back in recent years include details about the interstellar magnetic field and the abundance of cosmic rays.

“We’ve been very clever over the last 10 years to eke out every single little watt,” Dodd said. “Hopefully, one of them will make it to 50. But they are old and certainly events like this one that just happened scare the dickens out of me, as far as making that type of a milestone.”

PP