Next: Resolving idle time and continuous clocking , Previous: Clocking commands , Up: Clocking Work Time [ Contents ][ Index ]

8.4.2 The clock table
Org mode can produce quite complex reports based on the time clocking information. Such a report is called a clock table , because it is formatted as one or several Org tables.
Insert or update a clock table. When called with a prefix argument, jump to the first clock table in the current document and update it. The clock table includes archived trees.
This command can be invoked by calling org-dynamic-block-insert-dblock ( C-c C-x x ) and selecting “clocktable” (see Dynamic Blocks ).
Update dynamic block at point. Point needs to be in the ‘ BEGIN ’ line of the dynamic block.
Update all dynamic blocks (see Dynamic Blocks ). This is useful if you have several clock table blocks in a buffer.
Shift the current ‘ :block ’ interval and update the table. Point needs to be in the ‘ #+BEGIN: clocktable ’ line for this command. If ‘ :block ’ is ‘ today ’, it is shifted to ‘ today-1 ’, etc.
Here is an example of the frame for a clock table as it is inserted into the buffer by org-clock-report :
The ‘ #+BEGIN ’ line contains options to define the scope, structure, and formatting of the report. Defaults for all these options can be configured in the variable org-clocktable-defaults .
First there are options that determine which clock entries are to be selected:
Maximum level depth to which times are listed in the table. Clocks at deeper levels are summed into the upper level.
The scope to consider. This can be any of the following:
The time block to consider. This block is specified either absolutely, or relative to the current time and may be any of these formats:
When this option is not set, Org falls back to the value in org-clock-display-default-range , which defaults to the current year.
Use S- LEFT or S- RIGHT to shift the time interval.
A time string specifying when to start considering times. Relative times like ‘ "<-2w>" ’ can also be used. See Matching tags and properties for relative time syntax.
A time string specifying when to stop considering times. Relative times like ‘ "<now>" ’ can also be used. See Matching tags and properties for relative time syntax.
The starting day of the week. The default is 1 for Monday.
The starting day of the month. The default is 1 for the first.
Set to ‘ day ’, ‘ week ’, ‘ semimonth ’, ‘ month ’, ‘ quarter ’, or ‘ year ’ to split the table into chunks. To use this, either ‘ :block ’, or ‘ :tstart ’ and ‘ :tend ’ are required.
When non- nil , do not show steps that have zero time.
When non- nil , do not show table sections from files which did not contribute.
A tags match to select entries that should contribute. See Matching tags and properties for the match syntax.
Then there are options that determine the formatting of the table. There options are interpreted by the function org-clocktable-write-default , but you can specify your own function using the ‘ :formatter ’ parameter.
When non- nil , emphasize level one and level two items.
Language 78 to use for descriptive cells like “Task”.
Link the item headlines in the table to their origins.
An integer to limit the width of the headline column in the Org table. If you write it like ‘ 50! ’, then the headline is also shortened in export.
Indent each headline field according to its level.
Show title in the file column if the file has a ‘ #+title ’.
Hide the file column when multiple files are used to produce the table.
Number of columns to be used for times. If this is smaller than ‘ :maxlevel ’, lower levels are lumped into one column.
Should a level number column be included?
A cons cell containing the column to sort and a sorting type. E.g., ‘ :sort (1 . ?a) ’ sorts the first column alphabetically.
Abbreviation for ‘ :level nil :indent t :narrow 40! :tcolumns 1 ’. All are overwritten except if there is an explicit ‘ :narrow ’.
A timestamp for the entry, when available. Look for ‘ SCHEDULED ’, ‘ DEADLINE ’, ‘ TIMESTAMP ’ and ‘ TIMESTAMP_IA ’ special properties (see Special Properties ), in this order.
When this flag is non- nil , show the headline’s tags.
List of properties shown in the table. Each property gets its own column.
When this flag is non- nil , the values for ‘ :properties ’ are inherited.
Content of a ‘ TBLFM ’ keyword to be added and evaluated. As a special case, ‘ :formula % ’ adds a column with % time. If you do not specify a formula here, any existing formula below the clock table survives updates and is evaluated.
A function to format clock data and insert it into the buffer.
To get a clock summary of the current level 1 tree, for the current day, you could write:
To use a specific time range you could write 79
A range starting a week ago and ending right now could be written as
A summary of the current subtree with % times would be
A horizontally compact representation of everything clocked during last week would be
When using :step , untilnow starts from the beginning of 2003, not the beginning of time.
Language terms can be set through the variable org-clock-clocktable-language-setup .
Note that all parameters must be specified in a single line—the line is broken here only to fit it into the manual.

Daily movement news and resources

The Doomsday Clock Is About To Strike 12
- By Noam Chomsky, www.tomdispatch.com
- June 14, 2016
Above Photo: A huge cloud above Hiroshima, a few hours after the initial explosion on Aug. 6, 1945. (Hiroshima Peace Memorial Museum/U.S. Army via AP)
Note: Below is an excerpt from Noam Chomsky’s must-read new book, Who Rules the World?
Nuclear Weapons, Climate Change, and the Prospects for Survival
In January 2015, the Bulletin of the Atomic Scientists advanced its famous Doomsday Clock to three minutes before midnight, a threat level that had not been reached for 30 years. The Bulletin ’s statement explaining this advance toward catastrophe invoked the two major threats to survival: nuclear weapons and “unchecked climate change.” The call condemned world leaders, who “have failed to act with the speed or on the scale required to protect citizens from potential catastrophe,” endangering “every person on Earth [by] failing to perform their most important duty — ensuring and preserving the health and vitality of human civilization.”
Since then, there has been good reason to consider moving the hands even closer to doomsday.
As 2015 ended, world leaders met in Paris to address the severe problem of “unchecked climate change.” Hardly a day passes without new evidence of how severe the crisis is. To pick almost at random, shortly before the opening of the Paris conference, NASA’s Jet Propulsion Lab released a study that both surprised and alarmed scientists who have been studying Arctic ice. The study showed that a huge Greenland glacier, Zachariae Isstrom, “broke loose from a glaciologically stable position in 2012 and entered a phase of accelerated retreat,” an unexpected and ominous development. The glacier “holds enough water to raise global sea level by more than 18 inches (46 centimeters) if it were to melt completely. And now it’s on a crash diet, losing 5 billion tons of mass every year. All that ice is crumbling into the North Atlantic Ocean.”
Yet there was little expectation that world leaders in Paris would “act with the speed or on the scale required to protect citizens from potential catastrophe.” And even if by some miracle they had, it would have been of limited value, for reasons that should be deeply disturbing.
When the agreement was approved in Paris, French Foreign Minister Laurent Fabius, who hosted the talks, announced that it is “legally binding.” That may be the hope, but there are more than a few obstacles that are worthy of careful attention.
In all of the extensive media coverage of the Paris conference, perhaps the most important sentences were these, buried near the end of a long New York Times analysis: “Traditionally, negotiators have sought to forge a legally binding treaty that needed ratification by the governments of the participating countries to have force. There is no way to get that in this case, because of the United States. A treaty would be dead on arrival on Capitol Hill without the required two-thirds majority vote in the Republican-controlled Senate. So the voluntary plans are taking the place of mandatory, top-down targets.” And voluntary plans are a guarantee of failure.
“Because of the United States.” More precisely, because of the Republican Party, which by now is becoming a real danger to decent human survival.
The conclusions are underscored in another Times piece on the Paris agreement. At the end of a long story lauding the achievement, the article notes that the system created at the conference “depends heavily on the views of the future world leaders who will carry out those policies. In the United States, every Republican candidate running for president in 2016 has publicly questioned or denied the science of climate change, and has voiced opposition to Mr. Obama’s climate change policies. In the Senate, Mitch McConnell, the Republican leader, who has led the charge against Mr. Obama’s climate change agenda, said, ‘Before his international partners pop the champagne, they should remember that this is an unattainable deal based on a domestic energy plan that is likely illegal, that half the states have sued to halt, and that Congress has already voted to reject.’”
Both parties have moved to the right during the neoliberal period of the past generation. Mainstream Democrats are now pretty much what used to be called “moderate Republicans.” Meanwhile, the Republican Party has largely drifted off the spectrum, becoming what respected conservative political analyst Thomas Mann and Norman Ornstein call a “radical insurgency” that has virtually abandoned normal parliamentary politics. With the rightward drift, the Republican Party’s dedication to wealth and privilege has become so extreme that its actual policies could not attract voters, so it has had to seek a new popular base, mobilized on other grounds: evangelical Christians who await the Second Coming, nativists who fear that “they” are taking our country away from us, unreconstructed racists, people with real grievances who gravely mistake their causes, and others like them who are easy prey to demagogues and can readily become a radical insurgency.
In recent years, the Republican establishment had managed to suppress the voices of the base that it has mobilized. But no longer. By the end of 2015 the establishment was expressing considerable dismay and desperation over its inability to do so, as the Republican base and its choices fell out of control.
Republican elected officials and contenders for the next presidential election expressed open contempt for the Paris deliberations, refusing to even attend the proceedings. The three candidates who led in the polls at the time — Donald Trump, Ted Cruz, and Ben Carson — adopted the stand of the largely evangelical base: humans have no impact on global warming, if it is happening at all.
The other candidates reject government action to deal with the matter. Immediately after Obama spoke in Paris, pledging that the United States would be in the vanguard seeking global action, the Republican-dominated Congress voted to scuttle his recent Environmental Protection Agency rules to cut carbon emissions. As the press reported, this was “a provocative message to more than 100 [world] leaders that the American president does not have the full support of his government on climate policy” — a bit of an understatement. Meanwhile Lamar Smith, Republican head of the House’s Committee on Science, Space, and Technology, carried forward his jihad against government scientists who dare to report the facts.
The message is clear. American citizens face an enormous responsibility right at home.
A companion story in the New York Times reports that “two-thirds of Americans support the United States joining a binding international agreement to curb growth of greenhouse gas emissions.” And by a five-to-three margin, Americans regard the climate as more important than the economy. But it doesn’t matter. Public opinion is dismissed. That fact, once again, sends a strong message to Americans. It is their task to cure the dysfunctional political system, in which popular opinion is a marginal factor. The disparity between public opinion and policy, in this case, has significant implications for the fate of the world.
We should, of course, have no illusions about a past “golden age.” Nevertheless, the developments just reviewed constitute significant changes. The undermining of functioning democracy is one of the contributions of the neoliberal assault on the world’s population in the past generation. And this is not happening just in the U.S.; in Europe the impact may be even worse.
The Black Swan We Can Never See
Let us turn to the other (and traditional) concern of the atomic scientists who adjust the Doomsday Clock: nuclear weapons. The current threat of nuclear war amply justifies their January 2015 decision to advance the clock two minutes toward midnight. What has happened since reveals the growing threat even more clearly, a matter that elicits insufficient concern, in my opinion.
The last time the Doomsday Clock reached three minutes before midnight was in 1983, at the time of the Able Archer exercises of the Reagan administration; these exercises simulated attacks on the Soviet Union to test their defense systems. Recently released Russian archives reveal that the Russians were deeply concerned by the operations and were preparing to respond, which would have meant, simply: The End.
We have learned more about these rash and reckless exercises, and about how close the world was to disaster, from U.S. military and intelligence analyst Melvin Goodman, who was CIA division chief and senior analyst at the Office of Soviet Affairs at the time. “In addition to the Able Archer mobilization exercise that alarmed the Kremlin,” Goodman writes, “the Reagan administration authorized unusually aggressive military exercises near the Soviet border that, in some cases, violated Soviet territorial sovereignty. The Pentagon’s risky measures included sending U.S. strategic bombers over the North Pole to test Soviet radar, and naval exercises in wartime approaches to the USSR where U.S. warships had previously not entered. Additional secret operations simulated surprise naval attacks on Soviet targets.”
We now know that the world was saved from likely nuclear destruction in those frightening days by the decision of a Russian officer, Stanislav Petrov, not to transmit to higher authorities the report of automated detection systems that the USSR was under missile attack. Accordingly, Petrov takes his place alongside Russian submarine commander Vasili Arkhipov, who, at a dangerous moment of the 1962 Cuban Missile Crisis, refused to authorize the launching of nuclear torpedoes when the subs were under attack by U.S. destroyers enforcing a quarantine.
Other recently revealed examples enrich the already frightening record. Nuclear security expert Bruce Blair reports that “the closest the U.S. came to an inadvertent strategic launch decision by the President happened in 1979, when a NORAD early warning training tape depicting a full-scale Soviet strategic strike inadvertently coursed through the actual early warning network. National Security Adviser Zbigniew Brzezinski was called twice in the night and told the U.S. was under attack, and he was just picking up the phone to persuade President Carter that a full-scale response needed to be authorized right away, when a third call told him it was a false alarm.”
This newly revealed example brings to mind a critical incident of 1995, when the trajectory of a U.S.-Norwegian rocket carrying scientific equipment resembled the path of a nuclear missile. This elicited Russian concerns that quickly reached President Boris Yeltsin, who had to decide whether to launch a nuclear strike.
Blair adds other examples from his own experience. In one case, at the time of the 1967 Middle East war, “a carrier nuclear-aircraft crew was sent an actual attack order instead of an exercise/training nuclear order.” A few years later, in the early 1970s, the Strategic Air Command in Omaha “retransmitted an exercise… launch order as an actual real-world launch order.” In both cases code checks had failed; human intervention prevented the launch. “But you get the drift here,” Blair adds. “It just wasn’t that rare for these kinds of snafus to occur.”
Blair made these comments in reaction to a report by airman John Bordne that has only recently been cleared by the U.S. Air Force. Bordne was serving on the U.S. military base in Okinawa in October 1962, at the time of the Cuban Missile Crisis and a moment of serious tensions in Asia as well. The U.S. nuclear alert system had been raised to DEFCON 2, one level below DEFCON 1, when nuclear missiles can be launched immediately. At the peak of the crisis, on October 28th, a missile crew received authorization to launch its nuclear missiles, in error. They decided not to, averting likely nuclear war and joining Petrov and Arkhipov in the pantheon of men who decided to disobey protocol and thereby saved the world.
As Blair observed, such incidents are not uncommon. One recent expert study found dozens of false alarms every year during the period reviewed, 1977 to 1983; the study concluded that the range is 43 to 255 per year. The author of the study, Seth Baum, summarizes with appropriate words: “Nuclear war is the black swan we can never see, except in that brief moment when it is killing us. We delay eliminating the risk at our own peril. Now is the time to address the threat, because now we are still alive.”
These reports, like those in Eric Schlosser’s book Command and Control , keep mostly to U.S. systems. The Russian ones are doubtless much more error-prone. That is not to mention the extreme danger posed by the systems of others, notably Pakistan.
“A War Is No Longer Unthinkable”
Sometimes the threat has not been accident, but adventurism, as in the case of Able Archer. The most extreme case was the Cuban Missile Crisis in 1962, when the threat of disaster was all too real. The way it was handled is shocking; so is the manner in which it is commonly interpreted.
With this grim record in mind, it is useful to look at strategic debates and planning. One chilling case is the Clinton-era 1995 STRATCOM study “Essentials of Post-Cold War Deterrence.” The study calls for retaining the right of first strike, even against nonnuclear states. It explains that nuclear weapons are constantly used, in the sense that they “cast a shadow over any crisis or conflict.” It also urges a “national persona” of irrationality and vindictiveness to intimidate the world.
Current doctrine is explored in the lead article in the journal International Security , one of the most authoritative in the domain of strategic doctrine. The authors explain that the United States is committed to “strategic primacy” — that is, insulation from retaliatory strike. This is the logic behind Obama’s “new triad” (strengthening submarine and land-based missiles and the bomber force), along with missile defense to counter a retaliatory strike. The concern raised by the authors is that the U.S. demand for strategic primacy might induce China to react by abandoning its “no first use” policy and by expanding its limited deterrent. The authors think that they will not, but the prospect remains uncertain. Clearly the doctrine enhances the dangers in a tense and conflicted region.
The same is true of NATO expansion to the east in violation of verbal promises made to Mikhail Gorbachev when the USSR was collapsing and he agreed to allow a unified Germany to become part of NATO — quite a remarkable concession when one thinks about the history of the century. Expansion to East Germany took place at once. In the following years, NATO expanded to Russia’s borders; there are now substantial threats even to incorporate Ukraine, in Russia’s geostrategic heartland. One can imagine how the United States would react if the Warsaw Pact were still alive, most of Latin America had joined, and now Mexico and Canada were applying for membership.
Aside from that, Russia understands as well as China (and U.S. strategists, for that matter) that the U.S. missile defense systems near Russia’s borders are, in effect, a first-strike weapon, aimed to establish strategic primacy — immunity from retaliation. Perhaps their mission is utterly unfeasible, as some specialists argue. But the targets can never be confident of that. And Russia’s militant reactions are quite naturally interpreted by NATO as a threat to the West.
One prominent British Ukraine scholar poses what he calls a “fateful geographical paradox”: that NATO “exists to manage the risks created by its existence.”
The threats are very real right now. Fortunately, the shooting down of a Russian plane by a Turkish F-16 in November 2015 did not lead to an international incident, but it might have, particularly given the circumstances. The plane was on a bombing mission in Syria. It passed for a mere 17 seconds through a fringe of Turkish territory that protrudes into Syria, and evidently was heading for Syria, where it crashed. Shooting it down appears to have been a needlessly reckless and provocative act, and an act with consequences.
In reaction, Russia announced that its bombers will henceforth be accompanied by jet fighters and that it is deploying sophisticated anti-aircraft missile systems in Syria. Russia also ordered its missile cruiser Moskva , with its long-range air defense system, to move closer to shore, so that it may be “ready to destroy any aerial target posing a potential danger to our aircraft,” Defense Minister Sergei Shoigu announced. All of this sets the stage for confrontations that could be lethal.
Tensions are also constant at NATO-Russian borders, including military maneuvers on both sides. Shortly after the Doomsday Clock was moved ominously close to midnight, the national press reported that “U.S. military combat vehicles paraded Wednesday through an Estonian city that juts into Russia, a symbolic act that highlighted the stakes for both sides amid the worst tensions between the West and Russia since the Cold War.” Shortly before, a Russian warplane came within seconds of colliding with a Danish civilian airliner. Both sides are practicing rapid mobilization and redeployment of forces to the Russia-NATO border, and “both believe a war is no longer unthinkable.”
Prospects for Survival
If that is so, both sides are beyond insanity, since a war might well destroy everything. It has been recognized for decades that a first strike by a major power might destroy the attacker, even without retaliation, simply from the effects of nuclear winter.
But that is today’s world. And not just today’s — that is what we have been living with for 70 years. The reasoning throughout is remarkable. As we have seen, security for the population is typically not a leading concern of policymakers. That has been true from the earliest days of the nuclear age, when in the centers of policy formation there were no efforts — apparently not even expressed thoughts — to eliminate the one serious potential threat to the United States, as might have been possible. And so matters continue to the present, in ways just briefly sampled.
That is the world we have been living in, and live in today. Nuclear weapons pose a constant danger of instant destruction, but at least we know in principle how to alleviate the threat, even to eliminate it, an obligation undertaken (and disregarded) by the nuclear powers that have signed the Non-Proliferation Treaty. The threat of global warming is not instantaneous, though it is dire in the longer term and might escalate suddenly. That we have the capacity to deal with it is not entirely clear, but there can be no doubt that the longer the delay, the more extreme the calamity.
Prospects for decent long-term survival are not high unless there is a significant change of course. A large share of the responsibility is in our hands — the opportunities as well.
- Climate Change , Future , Nuclear Weapons
Independent media outlets are being suppressed and dropped by corporations like Google, Facebook and Twitter. Sign up for our daily email digest before it’s too late so you don’t miss the latest movement news.
- No suggested jump to results
- Notifications
📚 A template to create invoices using Org mode clock reports
woofers/org-invoice-template
Name already in use.
Use Git or checkout with SVN using the web URL.
Work fast with our official CLI. Learn more about the CLI .
- Open with GitHub Desktop
- Download ZIP
Sign In Required
Please sign in to use Codespaces.
Launching GitHub Desktop
If nothing happens, download GitHub Desktop and try again.
Launching Xcode
If nothing happens, download Xcode and try again.
Launching Visual Studio Code
Your codespace will open once ready.
There was a problem preparing your codespace, please try again.
Latest commit
Org mode invoice template.
A set of Org and LaTeX files which generate invoices using Org clock reports.

This template is heavily based on the template shown on Dima Kogan’s blog .
The styling is based on Trey Hunner’s invoice template .
Simply start clocking time using Org clocks in content/timesheet.org . The file should already contain an example timesheet.
Then edit content/info.org to include the correct date, consultant and client info.
Then when it’s time to generate the invoice, go into content/invoice.org and run org-invoice-generate .
All of the info from the timesheet will be used to fill-in the Services Breakdown and Balance Due fields.
Finally, export content/invoice.org as a LaTeX PDF to output the completed invoice.
The process should look something like this:
- Shell 41.2%
Stack Exchange Network
Stack Exchange network consists of 181 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Emacs Stack Exchange is a question and answer site for those using, extending or developing Emacs. It only takes a minute to sign up.
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
Time tracking and reporting with cross-cutting concerns in org-mode
I've been tracking my work time in org-mode for several years. My normal practice is to use clocktable mode in the agenda for daily tracking, and a clocktable block in my main projects file for monthly tracking. Both of these give me sums of my work time by file hierarchy, which in my org files corresponds to areas of responsibility and projects.
This is great, but now I need to be able to track time in this way, but also by type of activity (i.e., how much time on project management tasks, how much time on documentation, how much on customer meetings, etc.). I could tag the particular tasks I work on with tags for type of activity, but is there a way to get summed times (daily or monthly) by tag?
Has anyone had to do this (sum times in two different ways)? If so, what did you do?
- org-clock-table
- The info manual will probably answer all your questions: (info "(org) The clock table") . There is a :tags and a :block option to filter by tags and time. – mutbuerger Jul 21, 2016 at 14:13
- +1 Don't know why this question hasn't been upvoted out the wazoo. I've been trying to figure out how to do exactly this for ages, and came here via another attempt at figuring it out. And since I've had exposure to aspect oriented programming, when I saw "cross-cutting concerns" in my search results, I half expected to that it was simply one of my own questions asked a while ago. So I was glad to find at least one other person asking the same thing! – tkp Jan 11, 2017 at 12:59
This is straightforward by using the :tags option in clocktable lines, and I use this to do something similar to you. I have a separate org file ( clock.org in my case), which just contains clock tables with various time and project-specific tag filters. I then refresh the tables in this file when it comes time to pluck numbers out for a timesheet or whatever.
For example, the following reports time entries from the previous week that have a tag like "TAF001", "TAF002" etc (for time on change requests, in my case). This also includes an additional "TAGS" column so I can see which tags were on which item.
The :tags option takes a regular expression, so I make sure to include ^ to avoid incorrect matches if somehow the expression matches within a tag:
This also excludes anything tagged "NOCLOCK", and adds a percentage column in addition to reporting the raw time.
Your Answer
Sign up or log in, post as a guest.
Required, but never shown
By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct .

Not the answer you're looking for? Browse other questions tagged org-mode org-clock org-clock-table or ask your own question .
- The Overflow Blog
- How to use marketing techniques to build a better resume
- How the creator of Angular is dehydrating the web (Ep. 574)
- Featured on Meta
- AI/ML Tool examples part 3 - Title-Drafting Assistant
- We are graduating the updated button styling for vote arrows
- 2023 Community Moderator Election Results
- Middle Sidebar Advertising
Hot Network Questions
- Renaming .gpkg file in QGIS
- Which hardware wallets are technically capable of exporting the private key?
- Must a strong reducing agent be a weak oxidising agent, and vice versa?
- How far apart has the sun drifted from Alpha Centari due to the expansion of the universe since its formation?
- How to use the new LLMFunction?
- Align with three &
- How should I write leaving a PhD program after 6 years on the CV?
- How to quickly make a rectangular array of continous 1 and 0 given the start position of 1
- Democratic countries that limit the ability of foreign governments to influence their politics
- Feed forward neural network
- What kind of heating would occur during a suborbital re-entry?
- How to convert a simple matrix into circuit?
- How does GPL differ from CC BY-NC-SA?
- Is it possible to make a custom syntax coloring for "=", "==", and "==="?
- What does the mention of Israel suggest here in Greenmantle?
- How thick in diameter is the average Lightning bolt visually?
- Resultant of two polynomials
- Can you be fired for refusing to lie?
- For a finite set A of positive reals, prove that the set A + A - A contains at least as many positive as negative elements
- Is it appropriate to cite vulgar websites used for gathering data?
- Word for an intentionally high bid on a job
- MTB rear wheel selection
- Looking for an indicator light for 60-330V
- How to plot the graphics in the wolfram blog?
Your privacy
By clicking “Accept all cookies”, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy .
Your behavior appears to be a little unusual. Please verify that you are not a bot.

- Transportation
- Machine Control/Ag
- Current Issue
- Digital Editions
- 30th Anniversary Supplement
- Subscriber FAQ
- Buyers Guide
- White Papers
- GPS World on Instagram
Clocks fail on some Galileo satellites, backups working

Clocks have failed onboard several Galileo satellites in space, reports Phys.org , a web-based science, research and technology news service.
The cause of the failure is being investigated, European Space Agency director general Jan Woerner told journalists in Paris on Wednesday.
Each Galileo satellite has four atomic timekeepers — two rubidium and two hydrogen maser. Three rubidium and six hydrogen maser clocks are not working.

Passive hydrogen maser atomic clock of the type flown on Galileo, accurate to one second in three million years. (Photo: ESA)
The rubidium devices are similar to those used on current GPS satellites. The more precise hydrogen maser instruments were designed to give Galileo superior performance to the American GPS network.
Five of the maser failures have occurred on the satellites that were originally sent into orbit to validate the system, but all three rubidium stoppages are on the spacecraft that were subsequently launched to fill out the network, reports BBC News .
Each orbiter needs one working clock for the satellite navigation to work, with the other three clocks being spares. As of mid-January, 10 Galileo atomic clocks, the key element in a navigation satellite, had failed on four different satellites. One was recently returned to service, leaving nine outages, reports Space Intel Report .
Initial services were launched in December, and the failure of nine clocks out of 72 launched to date has not affected operation, Woerner said.
“If this failure has some systematic reason we have to be careful” not to place more flawed clocks in space, Woerner said. The question now is “should we postpone the next launch until we find the root cause?”
The next four satellites were to have been launched in August-September, but the launch has been postponed for November or December to investigate the clock failures. “You can say we wait until we find the solution, but that means if more clocks are failing then we are reducing the capability of Galileo,” Woener said.
The failures have occurred on two satellite platform designs: one built by Airbus and Thales Alenia Space as part of a four-satellite system validation program, and the other by Galileo prime contractor OHB SE of Germany, reports Space Intel Report. This is complicating the analysis to determine the cause of the failures.
Eighteen orbiters have been launched for the Galileo constellation to date, a number that will ultimately be boosted to 30 operational satellites and two spares.
You May Also Like

Seabed 2030 Project and NORBIT Oceans collaborate on global ocean mapping

KP Performance Antennas releases line of IoT antennas

Hexagon | NovAtel releases firmware with PTP functionality

XTEND acquires Performance Rotors
About the Author: GPS World Staff

Subscribe to GPS World
If you enjoyed this article, subscribe to GPS World to receive more articles just like it.
2 Comments on "Clocks fail on some Galileo satellites, backups working"
Trackback | Comments RSS Feed
Certainly it is smart to not place any more in orbit. that number of failures this soon points toward an assembly fault of some kind. Service calls to orbiting satellites are both difficult and expensive, which is why, normally, adequate testing is done on the ground prior to launch.
When I was operating cesiums, we found the old c-field would become irrational when a door was slammed down the hallway. Perhaps the shake-rattle-roll of launch and orbital insertion might be a good mission test for a 1st stage return of a Space-x with a clock on-board?

- Subscriber Services
- Contribute & Submit Stories
Digital Edition

© 2023 North Coast Media LLC, All Rights Reserved.
- Terms of Use
- Privacy Policy

IMAGES
COMMENTS
Source i (link to git-repo or to original if based on someone elses unmodified work):https://www.10wallpaper.com/wallpaper/1366x768/1809/Children_Flight_Clock_Abstract_Art_Design_1366x768.jpg. Children Flight Clock is part of Artwork
By Noam Chomsky for Tom Dispatch - In January 2015, the Bulletin of the Atomic Scientists advanced its famous Doomsday Clock to three minutes before midnight, a threat level that had not been reached for 30 years
A set of Org and LaTeX files which generate invoices using Org clock reports. Simply start clocking time using Org clocks in content/timesheet.org. Then edit content/info.org to include the correct date
This is straightforward by using the :tags option in clocktable lines, and I use this to do something similar to you. I have a separate org file (clock.org in my case), which just contains clock tables with
Analog clocks use a traditional clock face with hour, minute, and second hands. However, both types of clocks are typically accurate to within a few seconds. It can also be a useful life skill