Associate Administrator for NASA's Science Mission Directorate and former astronaut John M. Grunsfeld talked to the attendees of the The American Geophysical Union (AGU) meet at the Moscone Center in San Francisco, California. New results presented at the meeting show atmospheric rivers, significant sources of rainfall, tend to intensify during Nino events, and this years strong El Nino likely will bring more precipitation to California and some relief for the drought.

JSC2000-06750 (October 2000) --- Astronaut John M. Grunsfeld, mission specialist.

JSC2000-06749 (October 2000) --- Astronaut John M. Grunsfeld, mission specialist.

Students listen intently while Astronaut John Mace Grunsfeld speaks at NASA's Earth Day event. The event took place at Union Station in Washington, DC on April 22, 2014. Photo Credit: (NASA/Aubrey Gemignani)

NASA Associate Administrator for Science Mission Directorate John Grunsfeld talks during a NASA Future Forum panel discussion at The Ohio State University on, Monday, Feb. 20, 2012, in Columbus, Ohio. Monday marked the 50th anniversary of Glenn's historic flight as the first American to orbit Earth. Photo Credit: (NASA/Bill Ingalls)

S125-E-012353 (19 May 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, eats a meal on the middeck of the Earth-orbiting Space Shuttle Atlantis.

Sen. John Glenn, right, talks during a NASA Future Forum panel discussion at The Ohio State University as NASA Associate Administrator for Science Mission Directorate John Grunsfeld, left, and Ohio State University Graduate Research Associate Vijay Gadepally look on, Monday, Feb. 20, 2012, in Columbus, Ohio. Monday marked the 50th anniversary of Glenn's historic flight as the first American to orbit Earth. Photo Credit: (NASA/Bill Ingalls)

STS067-377-008 (2-18 March 1995) --- Astronaut John M. Grunsfeld, mission specialist, uses a handheld Hasselblad camera to record the Astro-2 payload. Orbiting Earth at 190 nautical miles, Grunsfeld joined four other NASA astronauts and two scientists for almost 17 days conducting research in support of the Astro-2 mission.

John Grunsfeld (at podium), Associate Administrator for the Science Mission Directorate at NASA Headquarters, asks one last question of the Mars Curiosity rover panel, Tuesday, March 12, 2013 in Washington. The news conference covered the findings that the analysis of the rock sample collected shows ancient Mars could have supported living microbes. Photo Credit: (NASA/Carla Cioffi)

Dr. John Grunsfeld, former astronaut and Deputy Director, Space Telescope Science Institute (STScI), Baltimore speaks at the presentation of the permanent exhibit of the James Webb Space Telescope at the Maryland Science Center on Wednesday, Oct. 26, 2011 in Baltimore. Photo Credit: (NASA/Carla Cioffi)

STS-125 Mission Specialist John Grunsfeld, right, talks with host Nick Clooney during a panel discussion, Monday, July 20, 2009, at the Newseum in Washington as part of the commemoration of the 40th Anniversary of the Apollo 11 moon landing. Photo Credit: (NASA/Bill Ingalls)

Dr. John Grunsfeld, former astronaut and Deputy Director, Space Telescope Science Institute (STScI), Baltimore speaks at the presentation of the permanent exhibit of the James Webb Space Telescope at the Maryland Science Center on Wednesday, Oct. 26, 2011 in Baltimore. Photo Credit: (NASA/Carla Cioffi)

NASA Astronaut and STS-125 Mission Specialist John Grunsfeld answers a question during a presentation with fellow STS-125 shuttle mission crew members at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA’s Twitter followers are in attendance. Photo Credit: (Carla Cioffi)

Astronaut John Grunsfeld speaks, Wednesday evening, Sept. 9, 2009, during a celebration of the Hubble Legacy at the National Air and Space Museum in Washington. Astronomers declared the Hubble Space Telescope a fully rejuvenated observatory with the release Wednesday of observations from four of its six operating science instruments. Grunsfeld, was a mission specialist aboard STS-125, the mission to repair the Hubble. Photo Credit: (NASA/Bill Ingalls)

John Grunsfeld, NASA Associate Administrator for the Science Mission Directorate, speaks during an Exploration Forum showcasing NASA's human exploration path to Mars in the James E. Webb Auditorium at NASA Headquarters on Tuesday, April 29, 2014. Photo Credit: (NASA/Joel Kowsky)

NASA Astronaut John Mace Grunsfeld takes a quick selfie with astronauts at the International Space Station at the NASA sponsored Earth Day event April 22, 2014 at Union Station in Washington, DC. NASA announced the "Global Selfie" event as part of its "Earth Right Now" campaign, celebrating the launch of five Earth-observing missions in 2014. All selfies posted to social media with the hashtag "GlobalSelfie" will be included in a mosaic image of Earth. Photo Credit: (NASA/Aubrey Gemignani)

John Grunsfeld, associate administrator for the Science Mission Directorate, NASA Headquarters, Washington, discusses the upcoming launch of the Mars Atmosphere and Volatile Evolution (MAVEN) mission, at a press conference at NASA Headquarters in Washington on Monday, Oct. 28th, 2013. MAVEN is the agency's next mission to Mars and the first devoted to understanding the upper atmosphere of the Red Planet. (Photo credit: NASA/Jay Westcott)

Members of the crew of STS-125, from left, Mission Specialists Andrew Feustel, Michael Good, Commander Scott Altman and Mission Specialist John Grunsfeld share a laugh with about the STS-125 mission to the Hubble Space Telescope during a visit by the crew to the Embassy of Italy in Washington, Thursday, July 23, 2009. Photo Credit: (NASA/Bill Ingalls)

NASA Associate Administrator Science John Grunsfeld, Ph.D, displays a fragment of the Pallasite meteorite from Chubut, Argentina found in 1951 and given to him by his daughter on Father's Day during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)

A participant at a NASA Social on the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission asks NASA Associate Administrator for the Science Mission Directorate John Grunsfeld a question, Thursday, Sept. 5, 2013 on Wallops Island, VA. Fifty of NASA's social media followers are attending a two-day event in support of the LADEE launch. Data from LADEE will provide unprecedented information about the environment around the moon and give scientists a better understanding of other planetary bodies in our solar system and beyond. LADEE is scheduled to launch at 11:27 p.m. Friday, Sept. 6, from NASA's Wallops Flight Facility. Photo Credit: (NASA/Carla Cioffi)

NASA Associate Administrator Robert Lightfoot, left, talks as NASA Associate Administrator Science John Grunsfeld, Ph.D, listens during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)

NASA Associate Administrator Science John Grunsfeld, Ph.D, talks during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)

NASA Associate Administrator for the Science Mission Directorate John Grunsfeld talks during a NASA Social about the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission at the NASA Wallops Flight Facility, Thursday, Sept. 5, 2013 on Wallops Island, VA. Fifty of NASA's social media followers are attending a two-day event in support of the LADEE launch. Data from LADEE will provide unprecedented information about the environment around the moon and give scientists a better understanding of other planetary bodies in our solar system and beyond. LADEE is scheduled to launch at 11:27 p.m. Friday, Sept. 6, from NASA's Wallops Flight Facility. Photo Credit: (NASA/Carla Cioffi)

NASA Associate Administrator Robert Lightfoot, left, talks as NASA Associate Administrator Science John Grunsfeld, Ph.D, listens, during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)

NASA Associate Administrator Science John Grunsfeld, Ph.D, talks during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)

The Ohio State University Vice President for Research Dr. Caroline Whitacre, standing right, moderates the first panel discussion during NASA's Future Forum with NASA Associate Administrator for Science Mission Directorate John Grunsfeld, left, Ohio State University Graduate Research Associate Vijay Gadepally, Sen. John Glenn, NASA Administrator Charles Bolden, and NASA 2009 Astronaut Candidate and Flight Surgeon Serena Auñón, seated right, at The Ohio State University on Monday, Feb. 20, 2012, in Columbus, Ohio. Monday marked the 50th anniversary of Glenn's historic flight as the first American to orbit Earth. Photo Credit: (NASA/Bill Ingalls)

STS-125 astronaut John Grunsfeld speaks during a press briefing at the new "Moving Beyond Earth," a new exhibition at the National Air and Space Museum in Washingon, Wednesday, Nov. 18, 2009. Moving Beyond Earth is an immersive exhibition that places visitors “in orbit” in the shuttle and space-station era to explore recent human spaceflight and future possibilities. Photo Credit: (NASA/Paul E. Alers)

STS-125 astronaut John Grunsfeld stands behind a display of Hubble memorabilia during a press briefing at the new "Moving Beyond Earth," a new exhibition at the National Air and Space Museum in Washingon, Wednesday, Nov. 18, 2009. Moving Beyond Earth is an immersive exhibition that places visitors “in orbit” in the shuttle and space-station era to explore recent human spaceflight and future possibilities. Photo Credit: (NASA/Paul E. Alers)

STS-125 astronaut John Grunsfeld speaks during a press briefing at the new "Moving Beyond Earth," a new exhibition at the National Air and Space Museum in Washingon, Wednesday, Nov. 18, 2009. Moving Beyond Earth is an immersive exhibition that places visitors “in orbit” in the shuttle and space-station era to explore recent human spaceflight and future possibilities. Photo Credit: (NASA/Paul E. Alers)

STS-125 crew member John Grunsfeld, left, looks on as crew member Michael Massimino holds up a part that was replaced on the Hubble Space Telescope, during a press conference, Wednesday, Sept. 9, 2009, after astronomers declared the telescope a fully rejuvenated observatory with the release Wednesday of observations from four of its six operating science instruments at NASA Headquarters in Washington. Photo Credit: (NASA/Paul E. Alers)

John Grunsfeld, NASA Associate Administrator for the Science Mission Directorate, is seen during during an event unveiling a new exhibit featuring Hubble's Corrective Optics Space Telescope Axial Replacement (COSTAR) and the Wide Field and Planetary Camera 2 (WFPC2) on Wednesday, April 23, 2014 at the Smithsonian National Air and Space Museum in Washington, DC. Grunsfeld flew on three of space shuttle servicing missions to Hubble, including the fifth and final mission in 2009 which returned COSTAR and WFPC2 to Earth. Photo Credit: (NASA/Joel Kowsky)

John Grunsfeld, NASA Associate Administrator for the Science Mission Directorate, speaks during an event unveiling a new exhibit featuring Hubble's Corrective Optics Space Telescope Axial Replacement (COSTAR) and the Wide Field and Planetary Camera 2 (WFPC2) on Wednesday, April 23, 2014 at the Smithsonian National Air and Space Museum in Washington, DC. Grunsfeld flew on three of space shuttle servicing missions to Hubble, including the fifth and final mission in 2009 which returned COSTAR and WFPC2 to Earth. Photo Credit: (NASA/Joel Kowsky)

John Grunsfeld, NASA Associate Administrator for the Science Mission Directorate, speaks during during an event unveiling a new exhibit featuring Hubble's Corrective Optics Space Telescope Axial Replacement (COSTAR) and the Wide Field and Planetary Camera 2 (WFPC2) on Wednesday, April 23, 2014 at the Smithsonian National Air and Space Museum in Washington, DC. Grunsfeld flew on three of space shuttle servicing missions to Hubble, including the fifth and final mission in 2009 which returned COSTAR and WFPC2 to Earth. Photo Credit: (NASA/Joel Kowsky)

NASA Associate Administrator for the Science Mission Directorate John Grunsfeld is seen in a video monitor during a NASA Social about the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission at the NASA Wallops Flight Facility, Thursday, Sept. 5, 2013 on Wallops Island, VA. Fifty of NASA's social media followers are attending a two-day event in support of the LADEE launch. Data from LADEE will provide unprecedented information about the environment around the moon and give scientists a better understanding of other planetary bodies in our solar system and beyond. LADEE is scheduled to launch at 11:27 p.m. Friday, Sept. 6, from NASA's Wallops Flight Facility. Photo Credit: (NASA/Carla Cioffi)

John Grunsfeld (far left), Associate Administrator for the Science Mission Directorate at NASA Headquarters, Dr. Francisco Javier Mendieta Jimenez, Director General of the Mexican Space Agency, NASA Administrator Charles Bolden, Leland Melvin, NASA Associate Administrator for Education and Al Condes (far right), Deputy Associate Administrator for International and Interagency Relations pose for a photo, Monday, March 18, 2013 at NASA Headquarters in Washington. A Reimbursable Space Act Agreement (RSAA) for a NASA International Internship Program was signed between the two agencies. This is the first NASA-Mexico agreement signed. Photo Credit: (NASA/Carla Cioffi)

John Grunsfeld, associate administrator for the Science Mission Directorate, NASA Headquarters, Washington, introduces a panel to discuss the upcoming launch of the Mars Atmosphere and Volatile Evolution (MAVEN) mission, at a press conference at NASA Headquarters in Washington on Monday, Oct. 28th, 2013. MAVEN is the agency's next mission to Mars and the first devoted to understanding the upper atmosphere of the Red Planet. (Photo credit: NASA/Jay Westcott)

Veteran journalist Nick Clooney, seated left, moderated a panel discussion with Apollo 11 astronaut Buzz Aldrin, far right, Charlie Duke of Apollo 16, John Grunsfeld, of the recent Hubble mission, and Goddard Space Flight Center deputy director Laurie Leshin, Monday, July 20, 2009, at the Newseum in Washington as part of the commemoration of the 40th Anniversary of the Apollo 11 moon landing. Photo Credit: (NASA/Bill Ingalls)

Italian Ambassador Giovanni Castellaneta, second from left, is presented with a montage by STS-125 Mission Specialist Mike Massimino, second from right, during a visit by the crew of STS-125 to the Embassy of Italy in Washington, Thursday, July 23, 2009. Other crew members, from left are Mission Specialists, Michael Good, Megan McArthur, John Grunsfeld, Commander Scott Altman and Andrew Feustel, far right. Photo Credit: (NASA/Bill Ingalls)

STS-125 shuttle mission crew members, from left, Scott Altman, Gregory Johnson, Megan McArthur, Andrew Feustel, John Grunsfeld, Michael Good and Michael Massimino, give a presentation at the NASA Tweetup event held at NASA Headquarters, July 21, 2009 in Washington. Nearly 200 of NASA's Twitter followers are in attendance, which featured a presentation and a question and answer session with the crew of the STS-125 shuttle mission to repair the Hubble Space Telescope. Photo Credit: (Carla Cioffi)

NASA Administrator Charle Bolden, Dr. John Grunsfeld, Dr. Piers Sellers, Goddard Center Director Chris Scolese and MSBR president Ms. Yang hold a meet and greet with Wounded Warriors from Fort Belvoir, MSBR Final Frontier Students and STEM Partners from Summer of Innovation local camps at Vital Signs: Taking the Pulse of Our Planet - Annual NASA reception and lecture hosted by the National Air and Space Museum and Sponsored by the Maryland Space Business Roundtable

NASA Administrator Charle Bolden, Dr. John Grunsfeld, Dr. Piers Sellers, Goddard Center Director Chris Scolese and MSBR president Ms. Yang hold a meet and greet with Wounded Warriors from Fort Belvoir, MSBR Final Frontier Students and STEM Partners from Summer of Innovation local camps at Vital Signs: Taking the Pulse of Our Planet - Annual NASA reception and lecture hosted by the National Air and Space Museum and Sponsored by the Maryland Space Business Roundtable

Dr. John Grunsfeld, former astronaut and Deputy Director, Space Telescope Science Institute (STScI), Baltimore, far right, speaks with U.S. Senator Barbara Mikulski about the James Webb Space Telescope at the Maryland Science Center in Baltimore on Wednesday, Oct. 26, 2011. Looking on are Van Reiner, President and CEO of the Maryland Science Center, Baltimore, far left; NASA Deputy Administrator Lori Garver and Jeffrey Grant, VP and General Manager of the Space Systems Division, Northrop Grumman. Photo Credit: (NASA/Carla Cioffi)

NASA Administrator Charle Bolden, Dr. John Grunsfeld, Dr. Piers Sellers, Goddard Center Director Chris Scolese and MSBR president Ms. Yang hold a meet and greet with Wounded Warriors from Fort Belvoir, MSBR Final Frontier Students and STEM Partners from Summer of Innovation local camps at Vital Signs: Taking the Pulse of Our Planet - Annual NASA reception and lecture hosted by the National Air and Space Museum and Sponsored by the Maryland Space Business Roundtable

Veteran journalist Nick Clooney, seated left, moderated a panel discussion with Apollo 11 astronaut Buzz Aldrin, far right, Charlie Duke of Apollo 16, John Grunsfeld, of the recent Hubble mission, and Goddard Space Flight Center deputy director Laurie Leshin, Monday, July 20, 2009, at the Newseum in Washington as part of the commemoration of the 40th Anniversary of the Apollo 11 moon landing. Photo Credit: (NASA/Bill Ingalls)

Veteran journalist Nick Clooney, seated left, moderated a panel discussion with Apollo 11 astronaut Buzz Aldrin, far right, Charlie Duke of Apollo 16, John Grunsfeld, of the recent Hubble mission, and Goddard Space Flight Center deputy director Laurie Leshin, Monday, July 20, 2009, at the Newseum in Washington as part of the commemoration of the 40th Anniversary of the Apollo 11 moon landing. Photo Credit: (NASA/Bill Ingalls)

NASA Associate Administrator Robert Lightfoot, left, talks as NASA Associate Administrator Science John Grunsfeld, Ph.D, second from left, NASA Associate Administrator for Space Technology, Mike Gazarik, Ph.D, and, NASA Associate Administrator for Human Exploration and Operations, William Gerstenmaier, right, look on during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)

NASA Associate Administrator for Human Exploration and Operations, William Gerstenmaier, right, talks as NASA Associate Administrator Robert Lightfoot, left, NASA Associate Administrator Science John Grunsfeld, Ph.D, second from left, and NASA Associate Administrator for Space Technology, Mike Gazarik, Ph.D, look on during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)

NASA, space science industry and government officials are seen in front of a full-size model of NASA's James Webb Space Telescope at the Maryland Science Center in Baltimore, Wednesday, Oct. 26, 2011. From left, back row are: Dr. John Grunsfeld, former astronaut and Deputy Director, Space Telescope Science Institute (STScI), Baltimore; Jeffrey Grant, VP and General Manager of the Space Systems Division, Northrop Grumman; Van Reiner, President and CEO of the Maryland Science Center, Baltimore and Adam Reiss, recipient of the 2011 Nobel Prize in Physics and professor of astronomy and physics at Johns Hopkins University. In the front row are NASA Deputy Administrator Lori Garver, left, and U.S. Senator Barbara Mikulski (D-Md.). Photo Credit: (NASA/Carla Cioffi)

U.S. Senator Barbara Mikulski (D-Md.), third from right, cuts the yellow ribbon presenting the James Webb Space Telescope permanent exhibit at the Maryland Science Center on Wednesday, Oct. 26, 2011 in Baltimore. Mikulski is joined by NASA Deputy Administrator Lori Garver, far left; Adam Reiss, recipient of the 2011 Nobel Prize in Physics and professor of astronomy and physics at Johns Hopkins University; Jeffrey Grant, VP and General Manager of the Space Systems Division, Northrop Grumman; Van Reiner, President and CEO of the Maryland Science Center, Baltimore and Dr. John Grunsfeld, former astronaut and Deputy Director, Space Telescope Science Institute (STScI), Baltimore. The Webb telescope will provide images of the first galaxies ever formed and explore planets around distant stars. Photo Credit: (NASA/Carla Cioffi)

Panelists (from left) Ellen Stofan, NASA Chief Scientist, left; John Grunsfeld, Associate Administrator for NASA's Science Mission DIrectorate, second from left; John Mather, Nobel Laureate and Senior Project Scientist for the James Webb Space Telescope (JWST) at NASA's Goddard Space Flight Center, third from left; Sara Seager, MacArthur Fellow and Professor of Planetary Science and Physics at the Massachusetts Institute of Technology, third from right; Dave Gallagher, Director for Astronomy and Physics at NASA's Jet Propulsion Laboratory, second from right; and Matt Mountain, Director of the Space Telescope Science Institute and Telescope Scientist for the JWST, right; are seen during a panel discussion on the search for life beyond Earth in the James E. Webb Auditorium at NASA Headquarters on Monday, July 14, 2014 in Washington, DC. The panel discussed how NASA's space-based observatories are making new discoveries and how the agency's new telescope, the James Webb Space Telescope, will continue this path of discovery after its schedule launch in 2018. Photo Credit: (NASA/Joel Kowsky)

STS-125 crew members from left, Commander Scott Altman, Pilot Gregory Johnson, Mission Specialist Michael Good, Mission Specialist Megan McArthur, Mission Specialist John Grunsfeld, Mission Specialist Michael Massimino and Mission Specialist Andrew Feustel, are seen during a press conference, Wednesday, Sept. 9, 2009, after astronomers declared the NASA's Hubble Space Telescope a fully rejuvenated observatory with the release Wednesday of observations from four of its six operating science instruments at NASA Headquarters in Washington. Photo Credit: (NASA/Paul E. Alers)

S92-45921 (21 Sept. 1992) --- Astronaut John M. Grunsfeld.

Onboard Space Shuttle Endeavour (STS-67) astronaut John Grunsfeld works at a laptop computer while wearing a headset. Commander Stephen Oswald watches Grunsfeld and Pilot Bill Gregory reads a checklist on the shuttle mid-deck.

Jazz pianist and singer Diana Krall holds a montage given to her by the STS-125 space shuttle crew along with Apollo 11 Astronaut Neil Armstrong at the Apollo 40th anniversary celebration held at the National Air and Space Museum, Monday, July 20, 2009 in Washington. From left, Michael J. Massimino, Michael T. Good, Gregory C. Johnson, Andrew J. Feustel, Krall, Scott D. Altman, Neil Armstrong, John M. Grunsfeld and Megan McArthur. Photo Credit: (NASA/Bill Ingalls)

JOHNSON SPACE CENTER, HOUSTON, TEXAS -- (JSC 2000-06750) -- Official portrait of astronaut John M. Grunsfeld, Mission Specialist

JOHNSON SPACE CENTER, HOUSTON, TEXAS -- (JSC 2000-06750) -- Official portrait of astronaut John M. Grunsfeld, Mission Specialist

S99-16048 (28 December 1999) --- Astronaut John M. Grunsfeld speaks at crew return ceremony at Ellington Field.

STS103-332-021 (19-27 December 1999) --- Astronaut John M. Grunsfeld, who.participated in two of the three STS-103 space walks to service the Hubble Space Telescope (HST), dons an extravehicular mobility unit (EMU) space suit for one of the walks. Grunsfeld is wearing the liquid cooling and ventilation garment that complements the EMU.

S125-E-007207 (14 May 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, participates in the first of his crew's five scheduled spacewalks in five consecutive days to perform the final hands-on servicing of the Hubble Space Telescope. Grunsfeld and his crewmate, astronaut Andrew Feustel, are slated for three of the five sessions.

Lori Garver, NASA Deputy Administrator, second from left, stands with members of the STS-125 crew and IMAX officials including Producer/Director Toni Myers, fifth from right, prior to the World Premiere of "Hubble 3D", screened at the Smithsonian's Air and Space Museum Tuesday evening, March 9, 2010, in Washington. Members of the STS-125 crew, dressed in their blue flight suits from left are; Mike Massimino, John Grunsfeld, Megan McArthur, Greg Johnson and Scott Altman. Photo Credit: (NASA/Paul E. Alers)

STS081-E-05144 (13 Jan. 1997) --- Making sure everything is in its place is no easy task as witnessed by the serious countenance of astronaut John M. Grunsfeld, mission specialist. Grunsfeld communicates with ground controllers as he checks progress of item transfers in the Spacehab Double Module (DM). This image was recorded with an Electronic Still Camera (ESC) and was later downlinked to flight controllers in Houston, Texas. Grunsfeld and five astronaut crew mates are preparing for a scheduled mid-week docking with Russia's Mir Space Station.

STS109-E-5290 (4 March 2002) --- Astronaut John M. Grunsfeld, payload commander, returns to the shirt-sleeve environment of the Space Shuttle Columbia's aft flight deck. Having completed a seven-hour space walk, Grunsfeld enters data in a lap top computer. Astronauts Grunsfeld and Richard M. Linnehan successfully replaced the Hubble Space Telescope's starboard solar array and are scheduled for two more space walks this week. The image was recorded with a digital still camera.

STS109-E-5448 (4 March 2002) --- Astronaut John M. Grunsfeld, payload commander, peers into the crew cabin of the Space Shuttle Columbia during the first STS-109 extravehicular activity (EVA-1) on March 4, 2002. Grunsfeld's helmet visor displays a mirrored image of the Earth's hemisphere. Astronauts Grunsfeld and Richard M. Linnehan replaced the starboard solar array on the Hubble Space Telescope (HST) on the first of five scheduled STS-109 space walks. The lower portion of the giant telescope can be seen over Grunsfeld's left shoulder. The image was recorded with a digital still camera by a crewmate on shuttle's aft flight deck.

S125-E-006621 (13 May 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, works with a power tool on the middeck of Space Shuttle Atlantis as he prepares for upcoming spacewalks to repair the Hubble Space Telescope.

Prince Philip, left, speaks with veteran space walkers John M. Grunsfeld, center, and Michael J. Massimino at NASA's Goddard Space Flight Center. Photo Credit: (NASA/Chris Gunn)

STS109-E-5904 (9 March 2002) --- Astronaut John M. Grunsfeld, STS-109 payload commander, holds a camera on the aft flight deck of the Space Shuttle Columbia. The image was recorded with a digital still camera.

JSC2002-E-05100 (15 February 2002) --- Astronaut John M. Grunsfeld, STS-109 payload commander, responds to a query during a pre-flight press conference at Johnson Space Center (JSC).

S125-E-007285 (13 May 2009) --- Astronaut Andrew Feustel (left) and John Grunsfeld, both STS-125 mission specialists, are pictured on the middeck of Space Shuttle Atlantis during flight day three activities.

S125-E-007006 (13 May 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, works on the aft flight deck of Space Shuttle Atlantis during flight day three activities.

JSC2002-E-09341 (13 March 2002) --- Astronaut John M. Grunsfeld, STS-109 payload commander, speaks from the lectern in Hangar 990 at Ellington Field during the crew return ceremonies.

S125-E-007862 (16 May 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, is about to attach a tether during a May 16 spacewalk to perform work on the Hubble Space Telescope.

JSC2009-E-087200 (23 April 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, fields a question from a reporter during a STS-125 preflight press briefing at NASA's Johnson Space Center.

JSC2006-E-47125 (31 Oct. 2006) --- Astronaut John M. Grunsfeld, STS-125 mission specialist for the newly announced final shuttle crew to visit and work on the Hubble Space Telescope.

STS81-E-05107 (13 Jan. 1997) --- Astronaut John M. Grunsfeld, mission specialist, begins to activate a biorack glovebox aboard the Spacehab Double Module (DM) early on Day 2 of the mission. Grunsfeld is joined by five other NASA astronauts for the almost ten-day mission. The crew is scheduled to dock with Russia's Mir Space Station and pick up John E. Blaha, NASA astronaut who has been serving as a cosmonaut guest researcher since September 1996. Jerry M. Linenger (out of frame) will replace Blaha onboard Mir.

JSC2002-00514 (February 2002)--- The STS-109 flight crew poses with the ascent and entry shift team in the Shuttle Flight Control Room of the Johnson Space Center's Mission Control Center. Flight Director John Shannon holds the mission insignia. Members of the flight crew are astronauts Scott D. Altman, commander; Duane G. Carey, pilot; John M. Grunsfeld, payload commander; and James H. Newman, Nancy J. Currie, Richard M. Linnehan and Michael J. Massimino, all mission specialists. Currie stands to the right of the logo, followed by, left to right, Altman, Grunsfeld, Newman and Massimino. Linnehan and Carey are not pictured.

STS109-E-5382 (6 March 2002) --- Astronaut John M. Grunsfeld, payload commander, waves at a crewmate inside Space Shuttle Columbia's crew cabin during a brief break in work on the Hubble Space Telescope (HST) in the cargo bay of the shuttle during the STS-109 mission's third space walk. The primary purpose of the extravehicular activity (EVA) of astronauts Grunsfeld and Richard M. Linnehan was to replace the Power Control Unit on the giant telescope. The image was recorded with a digital still camera by one of Grunsfeld's crew mates inside Columbia's cabin.

STS109-E-5420 (7 March 2002) --- Flight Day 7 of the STS-109 mission finds astronaut Richard M. Linnehan, mission specialist, back in the shirt-sleeve environment of the Space Shuttle Columbia, just like his space walking partner--astronaut John M. Grunsfeld (out of frame). Two of Grunsfeld's crewmates were about to begin the fourth space walk of the mission to perform special tasks on the Hubble Space Telescope (HST). Linnehan and Grunsfeld will participate in the fifth and final scheduled spacewalk in a little more than 24 hours. It will mark their third shared space walk for the current mission. This image was recorded with a digital still camera.

STS109-E-5381 (6 March 2002) --- Astronaut John M. Grunsfeld, payload commander, gives a "thumbs up" signal to crewmates inside Space Shuttle Columbia's crew cabin during a task on the Hubble Space Telescope (HST) in the cargo bay of the shuttle during the STS-109 mission's third space walk. The primary purpose of the extravehicular activity (EVA) of astronauts Grunsfeld and Richard M. Linnehan was to replace the Power Control Unit on the giant telescope. The image was recorded with a digital still camera by one of Grunsfeld's crew mates inside Columbia's cabin.

STS109-E-5377 (6 March 2002) --- Astronaut John M. Grunsfeld, payload commander, works in tandem with astronaut Richard M. Linnehan, mission specialist, as the two devote their attention to the Power Control Unit replacement task on the giant Hubble Space Telescope (HST). Grunsfeld stands on a foot restraint on the end of the Space Shuttle Columbia's Remote Manipulator System (RMS). This marked the third of five scheduled STS-109 space walks and the mission's second extravehicular activity (EVA) for the tandem of Grunsfeld and Linnehan. It was completed at 9:16 a.m. CST (1516 GMT), Mar. 6, 2002. The image was recorded with a digital still camera.

STS109-322-028 (6 March 2002) --- Astronaut Richard M. Linnehan, STS-109 mission specialist, participates in the third of five space walks to perform work on the Hubble Space Telescope (HST). Linnehan's sun shield reflects astronaut John M. Grunsfeld and the blue and white Earth's hemisphere as well as one of the telescope's new solar arrays. The third overall STS-109 extravehicular activity (EVA) marked the second of three for Linnehan and Grunsfeld, payload commander. On this particular walk, the two turned off the telescope in order to replace the power control unit or PCU--the heart of its power system. Grunsfeld took this photo with a 35mm camera.

STS109-E-5419 (7 March 2002) --- Flight Day 7 of the STS-109 mission finds payload commander John M. Grunsfeld back in the shirt-sleeve environment of the Space Shuttle Columbia. Two of Grunsfeld's crewmates were about to begin the fourth space walk of the mission to perform special tasks on the Hubble Space Telescope (HST). Grunsfeld will participate in the fifth and final scheduled spacewalk in a little more than 24 hours. It will mark his third space walk for the current mission. This image was recorded with a digital still camera.

STS109-E-5380 (6 March 2002) --- Astronaut John M. Grunsfeld, payload commander, waves at a crewmate inside Space Shuttle Columbia's crew cabin during a brief break in work on the Hubble Space Telescope (HST) in the cargo bay of the shuttle during the STS-109 mission's third space walk. The primary purpose of the extravehicular activity (EVA) of astronauts Grunsfeld and Richard M. Linnehan was to replace the Power Control Unit on the giant telescope. The image was recorded with a digital still camera by one of Grunsfeld's crew mates inside Columbia's cabin.

STS109-E-5378 (6 March 2002) --- Astronaut John M. Grunsfeld, payload commander, works in tandem with astronaut Richard M. Linnehan, mission specialist, as the two devote their attention to the Power Control Unit replacement task on the giant Hubble Space Telescope (HST). Grunsfeld stands on a foot restraint on the end of the Space Shuttle Columbia's Remote Manipulator System (RMS). This marked the third of five scheduled STS-109 space walks and the mission's second extravehicular activity (EVA) for the tandem of Grunsfeld and Linnehan. It was completed at 9:16 a.m. CST (1516 GMT), Mar. 6, 2002. The image was recorded with a digital still camera.

STS109-E-5447 (4 March 2002) --- Astronaut John M. Grunsfeld, payload commander, peers into the crew cabin of the Space Shuttle Columbia during the first STS-109 extravehicular activity (EVA-1) on March 4, 2002. Grunsfeld's helmet visor displays a mirrored image of the Earth's hemisphere. Astronauts Grunsfeld and Richard M. Linnehan replaced the starboard solar array on the Hubble Space Telescope (HST) on the first of five scheduled STS-109 space walks. The image was recorded with a digital still camera by a crewmate on shuttle's aft flight deck.

STS109-322-029 (6 March 2002) --- Astronaut John M. Grunsfeld, STS-109 payload commander, participates in the third of five space walks to perform work on the Hubble Space Telescope (HST). The third overall STS-109 extravehicular activity (EVA) marked the second of three for Grunsfeld, who was joined by astronaut Richard M. Linnehan on them all. On this particular walk, astronauts Grunsfeld and Linnehan turned off the telescope in order to replace its power control unit or PCU, the heart of the HST’s power system.

S125-E-007789 (15 May 2009) --- Astronaut John Grunsfeld signals "thumbs up" to indicate two of his crewmates coming inside from a lengthy space walk are "home." Grunsfeld had just opened the hatch that leads from the mid deck to the airlock. Completing this day's session of extravehicular activity and in the airlock when this photo was made were astronauts Mike Massimino and Michael Good.

S99-06191 (21 June 1999) --- Astronaut John M. Grunsfeld, mission specialist, wearing an underwater-adapted training version of the Shuttle extravehicular mobility unit (EMU), prepares to go below the water in the Neutral Buoyancy Laboratory (NBL). Grunsfeld and other astronauts assigned to STS-103 space walk duty are in training for EVA chores they will handle when they make the third servicing visit to the Earth-orbiting Hubble Space Telescope (HST) since its deployment in April of 1990.

S125-E-007223 (14 May 2009) --- Astronaut John Grunsfeld performs work on the Hubble Space Telescope as the first of five STS-125 spacewalks kicks off a week?s worth of work on the orbiting observatory. Grunsfeld, a spacewalk veteran with a long relationship with the telescope, will participate in two of the remaining four sessions of extravehicular activity later in the mission.

JSC2008-E-006306 (22 Jan. 2008) --- Astronaut John M. Grunsfeld, STS-125 mission specialist, participates in an Extravehicular Mobility Unit (EMU) spacesuit fit check in the Space Station Airlock Test Article (SSATA) in the Crew Systems Laboratory at the Johnson Space Center. Astronaut Michael T. Good (right), mission specialist, and United Space Alliance (USA) suit technician James Lemmon assisted Grunsfeld.

S103-E-5209 --- Astronauts Steven L. Smith (bottom), payload commander, and John M. Grunsfeld, mission specialist, perform servicing tasks on the temporarily-captured Hubble Space Telescope (HST). Grunsfeld is on a foot restraint connected to Discovery's remote manipulator system (RMS) robot arm. Smith, making his second servicing visit to HST, is using handrails on the telescope. The photo was taken with an electronic still camera (ESC).

STS-103 mission specialist John M. Grunsfeld (attached to a workstation on the RMS arm) and payload commander Steven L. Smith (free-floating) perform a changeout of the Rate Sensor Units (RSU) in one of the bays of -V3 plane of the Hubble Space Telescope (HST). This repair was performed during the first of three extravehicular activities (EVAs) of the mission. Grunsfeld is distinguished by having no marks on his EMU and Smith is distinguished by the red strip on the pants of his EMU.

STS-103 mission specialist John M. Grunsfeld (attached to a workstation on the RMS arm) and payload commander Steven L. Smith (free-floating) perform a changeout of the Rate Sensor Units (RSU) in one of the bays of -V3 plane of the Hubble Space Telescope (HST). This repair was performed during the first of three extravehicular activities (EVAs) of the mission. Grunsfeld is distinguished by having no marks on his EMU and Smith is distinguished by the red strip on the pants of his EMU.

S125-E-009713 (18 May 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, participates in the mission?s fifth and final session of extravehicular activity (EVA) as work continues to refurbish and upgrade the Hubble Space Telescope. During the seven-hour and two-minute spacewalk, Grunsfeld and astronaut Andrew Feustel (out of frame), mission specialist, installed a battery group replacement, removed and replaced a Fine Guidance Sensor and three thermal blankets (NOBL) protecting Hubble?s electronics.

JSC2007-E-113485 (17 Dec. 2007) --- Astronaut John M. Grunsfeld, STS-125 mission specialist, dons a training version of the Extravehicular Mobility Unit (EMU) spacesuit prior to being submerged in the waters of the Neutral Buoyancy Laboratory (NBL) near the Johnson Space Center. Astronauts Andrew J. Feustel (left) and Michael J. Massimino, both mission specialists, assisted Grunsfeld.

S125-E-009712 (18 May 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, participates in the mission?s fifth and final session of extravehicular activity (EVA) as work continues to refurbish and upgrade the Hubble Space Telescope. During the seven-hour and two-minute spacewalk, Grunsfeld and astronaut Andrew Feustel (out of frame), mission specialist, installed a battery group replacement, removed and replaced a Fine Guidance Sensor and three thermal blankets (NOBL) protecting Hubble?s electronics.

S125-E-007853 (16 May 2009) --- Astronaut Andrew Feustel, STS-125 mission specialist, navigates near the Hubble Space Telescope on the end of the remote manipulator system arm, controlled from inside Atlantis? crew cabin. Astronaut John Grunsfeld signals to his crewmate from just a few feet away. Astronauts Feustel and Grunsfeld were continuing servicing work on the giant observatory, locked down in the cargo bay of the shuttle.

S125-E-006501 (12 May 2009) --- Astronaut John Grunsfeld, mission specialist, helps with unpacking chores on Atlantis? mid deck during the STS-125 flight?s second day in space. The next several days prove to be very busy for the entire crew, as five spacewalks, three of which will have the veteran Grunsfeld leaving the shirt sleeved environment of the shuttle, are in the offing.

STS109-E-5225 (4 March 2002) --- Astronaut John M. Grunsfeld, payload commander, signals readiness for the first the first of his assigned STS-109 space walks to perform work on the Hubble Space Telescope (HST). Astronauts Grunsfeld and Richard M. Linnehan moments later egressed the Space Shuttle Columbia's airlock, eventually replacing the giant telescope’s starboard solar array during a space walk that ended at 7:38 a.m. (CST) or 13:38 GMT March 4, 2002.

S125-E-009593 (18 May 2009) --- Astronaut John Grunsfeld, STS-125 mission specialist, participates in the mission?s fifth and final session of extravehicular activity (EVA) as work continues to refurbish and upgrade the Hubble Space Telescope. During the seven-hour and two-minute spacewalk, Grunsfeld and astronaut Andrew Feustel (out of frame), mission specialist, installed a battery group replacement, removed and replaced a Fine Guidance Sensor and three thermal blankets (NOBL) protecting Hubble?s electronics.

S125-E-009603 (18 May 2009) --- Astronauts John Grunsfeld (left) and Andrew Feustel, both STS-125 mission specialists, participate in the mission?s fifth and final session of extravehicular activity (EVA) as work continues to refurbish and upgrade the Hubble Space Telescope. During the seven-hour and two-minute spacewalk, Grunsfeld and Feustel installed a battery group replacement, removed and replaced a Fine Guidance Sensor and three thermal blankets (NOBL) protecting Hubble?s electronics.