Sentences with phrase «reaction wheels»

Kepler, which was initially expected to last until 2016, encountered a serious anomaly when the second of its four reaction wheels failed in May 2013, disabling the spacecraft to collect data.

At this low - altitude mapping orbit, Dawn will begin using a method of pointing control that engineers have dubbed «hybrid» mode because it utilizes a combination of reaction wheels and thrusters to point the spacecraft.

Kepler was crippled after two of its four reaction wheels malfunctioned but the mission's data has been used to discover hundreds of new planets.

Such plans would use the spacecraft and its single instrument to perform different kinds of experiments that would not require the exquisite pointing precision that three working reaction wheels gave Kepler.

As astronomers presented new planetary measurements and observing techniques at the conference, Kepler engineers in California were strategizing about how to remotely repair one of two broken reaction wheels that precisely point the telescope.

(Its stabilizing reaction wheels later broke and it began a new mission called K2 (SN Online: 5/15/13).)

Reaction wheels do fail all the time, some fail quite early, some go on for decades without any problem.

Those photons exert just enough pressure to push the spacecraft around a little bit, which is what the telescope's reaction wheels try to counteract.

Instead, the HST has reaction wheels oriented in the three directions of motion (x / y / z or pitch / roll / yaw).

The new method of balancing Kepler on just two reaction wheels relies on pressure from photons from the sun.

• Replacement # 1 of 4 Reaction Wheel Assemblies (RWA), with refurbished spare.

The Kepler space telescope was taken for a goner when one of its steadying reaction wheels broke.

It was only when a second (of four) reaction wheels developed excessive friction while Dawn was leaving Vesta in 2012 that mission managers decided to use the hybrid mode at Ceres.

In May 2013, the second of four reaction wheels failed, making it impossible to accurately position the spacecraft for observations.

For that kind of precision pointing, it needed to have at least three working reaction wheels to steer it and hold it in place.

Kepler operated from 2009 to 2013 when it was hobbled by the failure of stabilizing reaction wheels.

On January 10, engineers sent a command to spin Philae's reaction wheel, which helped stabilize the lander during its descent.

But by May, two of these reaction wheels had stopped working, ending Kepler's ability to spot planets.

Even worse, the reaction wheels used to point the spacecraft wore out earlier than planned, bringing the primary mission to a premature end in 2013.

After losing two of its reaction wheels, which balanced the spacecraft, Kepler could no longer stay steady enough to stare at stars and detect planets.

By May, two of the four reaction wheels that precisely point the telescope had failed, leaving it too unstable to detect exoplanets around bright stars.

That's because engineers have been unable to revive the functionality of two of the spacecraft's four reaction wheels, which are necessary to keep it precisely pointed at target stars.

Although no formal agreement was reached, the two sides agreed that NASA would contribute a piece of hardware such as detectors or reaction wheels — which help turn a space observatory in a desired direction — and, in turn, gain a seat on Euclid's 12 - member science team.

After 4 years of faithful service, a reaction wheel malfunction may have scuppered the planet - hunting Kepler spacecraft for good.

Though Kepler's planet - hunting has come to a halt due to damage to its reaction wheels, there's still plenty of data to sift through, scientists say.

That left only two reaction wheels, not enough for Kepler to keep up its planet - hunting work.

Three onboard systems allow the telescope to remain fixed on an object: gyroscopes, the Fine Guidance Sensors that we talked about in the previous section, and reaction wheels.

The reaction wheels are flywheels, like those found in a clutch.

She listed half a dozen systems or components on Cassini that stopped working during its lifetime, including some of the probe's thrusters and a reaction wheel, both of which are necessary to steer the spacecraft.

Kepler was approved far beyond its original mission length and was operating well until May 2013, when a second of its four reaction wheels or gyroscopes failed.

The flight computer then directs the reaction wheels to move the telescope.

The discovery is all the more remarkable because Kepler is now hobbled by the loss of two reaction wheels that kept it pointing at a fixed spot in space.

«Last summer, the possibility of a scientifically productive mission for Kepler after its reaction wheel failure in its extended mission was not part of the conversation,» Paul Hertz, NASA's astrophysics division director at the agency's headquarters in Washington, said in a statement.

Abstract: NASA's exoplanet Discovery mission Kepler was reconstituted as the K2 mission a year after the failure of the 2nd of Kepler's 4 reaction wheels in May 2013.

Despite these roll errors, the flight system and its modified... ▽ More NASA's exoplanet Discovery mission Kepler was reconstituted as the K2 mission a year after the failure of the 2nd of Kepler's 4 reaction wheels in May 2013.

These results mark the end of the first official Kepler mission, which was cut short four years ago by a second failed reaction wheel that stabilized the telescope.

In August, engineers at Langley Research Center in Hampton, Va., sent out a call for ideas on how they could use the two reaction wheels and Kepler's thrusters together — rather like using a cane to help the spacecraft as it hobbles around on two wheels — and what resources it would take to get the spacecraft on its feet, however shakily.

Reaction wheels that help the craft focus on far - off stars «are sufficiently damaged that they can not sustain spacecraft pointing control for any extended period of time,» he said, adding that the space agency will now focus on figuring out how it might still use the telescope with only two fully functioning reaction wheels.

This mission collected about four years of data before two of its reaction wheels failed, crippling the spacecraft.

If Kepler can be oriented so that the photon pressure is evenly distributed (see diagram above), the two working reaction wheels can be used to point the telescope at a fixed point.

When a reaction wheel on the Compton Gamma Ray Observatory — one of the four Great Observatories, along with the Hubble Space Telescope, Spitzer and the Chandra X-Ray Observatory — failed in 1999, the space agency made the decision to deorbit the spacecraft and force it into a controlled crash landing, rather than risk an uncontrolled fall if another reaction wheel failed.

In July 2012, one of Kepler's four reaction wheels failed; then in May 2013, a second one failed, leaving just two that were operational.

Kepler mission planners revived the telescope in 2013, after the malfunction of the second of its four reaction wheels — devices that help control the orientation of the spacecraft.

With NASA giving up on fixing the reaction wheels, it is now unlikely that Kepler will meet those goals.

The wheels work a lot like gyroscopes: When a reaction wheel turns, the spacecraft counter-rotates according to the law of conservation of angular momentum.

At this lowest orbit, using two of the reaction wheels to help with pointing will provide the biggest hydrazine savings.