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Astronomers Use Innovative Technique to Find Extrasolar Planet
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By NASA
Robert Williams is a senior mechanical design engineer and the structures subject matter expert in the Engineering and Test Directorate at NASA’s Stennis Space Center.NASA/Danny Nowlin Living up to, and maintaining, the standard of excellence associated with NASA is what drives Robert Williams at NASA’s Stennis Space Center near Bay St. Louis, Mississippi.
A native of Gulfport, Mississippi, Williams said he has had the opportunity to work with and be mentored by “some truly exceptional” engineers, some with careers reaching back to the Apollo era.
“I cannot overstate the vast amount of practical knowledge and experience we have at NASA Stennis,” Williams said. “We know how to get things done, and if we do not know, I can guarantee we will figure it out.”
Williams is a senior mechanical design engineer and the structures subject matter expert for the NASA Stennis Engineering and Test Directorate.
He provides technical oversight related to engineering mechanics and machine design by reviewing analysis and design packages from NASA Stennis contractors and NASA engineers for ongoing projects.
Williams also supports projects by performing analysis and creating detailed models, drawings, and system level designs, mostly at the versatile four-stand E Test Complex, where NASA Stennis has 12 active test cells capable of various component, engine, and stage test activities to support the agency and commercial companies.
In support of NASA’s Artemis campaign of returning astronauts to the Moon, Williams also has reviewed structural and pipe stress analysis for the exploration upper stage project that will test a new SLS (Space Launch System) rocket stage to fly on future Artemis missions.
He performed similar review work for Green Run testing of the SLS core stage at NASA Stennis ahead of the successful launch of the Artemis I uncrewed mission around the Moon.
Overall, Williams has been a part of projects on every test stand throughout more than eight years with NASA and five years as a contractor. He has been tasked with solving challenging problems, both individually and as a part of teams.
There were times when he was not sure if he or the team would be able to solve the problem or address it effectively, but each time, the NASA Stennis team found a way.
“Over the span of my career, I have yet to be in a situation where the challenge was not met,” he said.
The opportunity to work with “pretty much all the major space companies in some capacity” is most interesting to Williams. “The best thing is that being a small organization within a relatively small center, there are always opportunities to develop new skills and capabilities to help fill a need or gap,” he said.
No matter the task, Williams looks forward to supporting space innovation while living up to, and maintaining, the standard of excellence associated with NASA for the benefit of all.
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By NASA
4 min read
May’s Night Sky Notes: How Do We Find Exoplanets?
Astronomers have been trying to discover evidence that worlds exist around stars other than our Sun since the 19th century. By the mid-1990s, technology finally caught up with the desire for discovery and led to the first discovery of a planet orbiting another sun-like star, Pegasi 51b. Why did it take so long to discover these distant worlds, and what techniques do astronomers use to find them?
The Transit Method
A planet passing in front of its parent star creates a drop in the star’s apparent brightness, called a transit. Exoplanet Watch participants can look for transits in data from ground-based telescopes, helping scientists refine measurements of the length of a planet’s orbit around its star. Credit: NASA’s Ames Research Center One of the most famous exoplanet detection methods is the transit method, used by Kepler and other observatories. When a planet crosses in front of its host star, the light from the star dips slightly in brightness. Scientists can confirm a planet orbits its host star by repeatedly detecting these incredibly tiny dips in brightness using sensitive instruments. If you can imagine trying to detect the dip in light from a massive searchlight when an ant crosses in front of it, at a distance of tens of miles away, you can begin to see how difficult it can be to spot a planet from light-years away! Another drawback to the transit method is that the distant solar system must be at a favorable angle to our point of view here on Earth – if the distant system’s angle is just slightly askew, there will be no transits. Even in our solar system, a transit is very rare. For example, there were two transits of Venus visible across our Sun from Earth in this century. But the next time Venus transits the Sun as seen from Earth will be in the year 2117 – more than a century from the 2012 transit, even though Venus will have completed nearly 150 orbits around the Sun by then!
The Wobble Method
As a planet orbits a star, the star wobbles. This causes a change in the appearance of the star’s spectrum called Doppler shift. Because the change in wavelength is directly related to relative speed, astronomers can use Doppler shift to calculate exactly how fast an object is moving toward or away from us. Astronomers can also track the Doppler shift of a star over time to estimate the mass of the planet orbiting it. NASA, ESA, CSA, Leah Hustak (STScI) Spotting the Doppler shift of a star’s spectra was used to find Pegasi 51b, the first planet detected around a Sun-like star. This technique is called the radial velocity or “wobble” method. Astronomers split up the visible light emitted by a star into a rainbow. These spectra, and gaps between the normally smooth bands of light, help determine the elements that make up the star. However, if there is a planet orbiting the star, it causes the star to wobble ever so slightly back and forth. This will, in turn, cause the lines within the spectra to shift ever so slightly towards the blue and red ends of the spectrum as the star wobbles slightly away and towards us. This is caused by the blue and red shifts of the star’s light. By carefully measuring the amount of shift in the star’s spectra, astronomers can determine the size of the object pulling on the host star and if the companion is indeed a planet. By tracking the variation in this periodic shift of the spectra, they can also determine the time it takes the planet to orbit its parent star.
Direct Imaging
Finally, exoplanets can be revealed by directly imaging them, such as this image of four planets found orbiting the star HR 8799! Space telescopes use instruments called coronagraphs to block the bright light from the host star and capture the dim light from planets. The Hubble Space Telescope has captured images of giant planets orbiting a few nearby systems, and the James Webb Space Telescope has only improved on these observations by uncovering more details, such as the colors and spectra of exoplanet atmospheres, temperatures, detecting potential exomoons, and even scanning atmospheres for potential biosignatures!
NASA’s James Webb Space Telescope has provided the clearest look in the infrared yet at the iconic multi-planet system HR 8799. The closest planet to the star, HR 8799 e, orbits 1.5 billion miles from its star, which in our solar system would be located between the orbit of Saturn and Neptune. The furthest, HR 8799 b, orbits around 6.3 billion miles from the star, more than twice Neptune’s orbital distance. Colors are applied to filters from Webb’s NIRCam (Near-Infrared Camera), revealing their intrinsic differences. A star symbol marks the location of the host star HR 8799, whose light has been blocked by the coronagraph. In this image, the color blue is assigned to 4.1 micron light, green to 4.3 micron light, and red to the 4.6 micron light. NASA, ESA, CSA, STScI, W. Balmer (JHU), L. Pueyo (STScI), M. Perrin (STScI) You can find more information and activities on NASA’s Exoplanets page, such as the Eyes on Exoplanets browser-based program, The Exoplaneteers, and some of the latest exoplanet news. Lastly, you can find more resources in our News & Resources section, including a clever demo on how astronomers use the wobble method to detect planets!
The future of exoplanet discovery is only just beginning, promising rich rewards in humanity’s understanding of our place in the Universe, where we are from, and if there is life elsewhere in our cosmos.
Originally posted by Dave Prosper: July 2015
Last Updated by Kat Troche: April 2025
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By NASA
2 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
EnerVenue’s batteries don’t require energy-consuming temperature control or maintenance and can be stored anywhere, including in the company’s “EnerStation” battery station, pictured here.Credit: EnerVenue, Inc. Battery technology that has powered the International Space Station, the Hubble Space Telescope, and numerous satellites is now storing energy on Earth, enabling intermittent renewable energy sources to provide steady power.
These extremely durable batteries were made more affordable for the average consumer by California-based EnerVenue Inc., which was able to bring down the cost of the technology by removing the need for expensive platinum, making terrestrial applications more feasible. With the cost-saving innovations, the batteries could be used for power plants, businesses, and homes.
NASA first used nickel-hydrogen batteries in 1990 for the Hubble Space Telescope — the technology’s debut in low-Earth orbit on a major project. It was the primary power system for the International Space Station for more than 18 years before eventually being replaced by lithium-ion batteries.
Each nickel-hydrogen cell consists of a nickel cathode — the positive electrode — and a hydrogen-catalyzed anode, which typically uses expensive platinum. Charging the battery generates hydrogen inside the highly pressurized vessel, which then gets reabsorbed on discharge.
Dr. Yi Cui , EnerVenue Chief Technology Advisor, developed a technique to remove platinum from these batteries, dramatically reducing costs of technology that had grown more sophisticated over decades of NASA adapting it to high-level missions. Much of the groundwork for EnerVenue’s batteries was laid by NASA.
Having laid the foundation and tested it in space, NASA paved the way for a durable power source that is now available for several applications on Earth.
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Last Updated Apr 24, 2025 Related Terms
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
As associate administrator for NASA’s Space Operations Mission Directorate Ken Bowersox puts it, “nothing happens without communications.”
And effective communications require the use of radio waves.
None of NASA’s exciting science and engineering endeavors would be possible without the use of radio waves to send data, communications, and commands between researchers or flight controllers and their flight platforms or instruments.
Reflecting on his time as a pilot, commander, and mission specialist during the Space Shuttle Program, Bowersox says, “If you’re not there physically, you can’t be a part of the team. But if you’re getting the data, whether it’s video, telemetry data with states of switches, or individual parameters on temperatures or pressures, then you can act on it and provide information to the spacecraft team so they can do the right thing in their operation.”
These vital data and communications functions, as well as the gathering of valuable scientific data through remote sensing applications, all use radio frequencies (RF) within the electromagnetic spectrum. NASA centers and facilities also use the RF spectrum to support their everyday operations, including the walkie-talkies used by security guards, air traffic control systems around airfields, and even office Wi-Fi routers and wireless keyboards.
Nothing happens without communications.
Ken Bowersox
NASA Astronaut & Associate Administrator for NASA's Space Operations Mission Directorate
All of NASA’s uses of the RF spectrum are shared, with different radio services supporting other kinds of uses. Service allocation is a fundamental concept in spectrum regulation and defines how the spectrum is shared between different types of applications. A service allocation defines ranges, or bands, of radio frequencies that can be used by a particular type of radio service. For example, a television broadcasting satellite operates in frequency bands allocated to the broadcasting satellite service, terrestrial cellular services operate in bands allocated for the mobile service, and the communications antennas on the International Space Station (ISS) operate in bands allocated to space operations service.
However, an allocation is not a license to operate — it does not authorize a specific system or operator to use particular frequencies. Such authority is granted through domestic and international regulatory processes.
Most frequency bands of the RF spectrum are shared, and each frequency band typically has two or more radio services allocated to it. Careful spectrum regulation, planning, and management aim to identify mutually compatible services to share frequency bands while limiting its negative impacts.
NASA’s Most Notable Spectrum Uses
Many of NASA’s most notable uses of spectrum rely on the following service allocations:
Earth exploration-satellite service Space research service Space operations service Inter-satellite service Note that allocations in the Earth exploration-satellite service and the space research service are designated either for communications links in the Earth-to-space, space-to-Earth, or space-to-space directions or designated for active or passive sensing of Earth or celestial objects (respectively) to differentiate the types of uses within the service and afford the requisite protections.
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Watch the video to learn more about how each kind of system uses the radio frequency spectrumNASA Learn how NASA manages its use of the RF spectrum. Learn about who NASA collaborates with to inform the spectrum regulations of the future. Learn about the scientific principles of the electromagnetic spectrum, including radio waves. Share
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By European Space Agency
Registrations are now open for the European Space Agency’s Living Planet Symposium (LPS) – one of the largest Earth observation conferences in the world. The event will take place on 23–27 June 2025 in Vienna, Austria.
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