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Official site of the design, build, test and launch of JWST.


Overview of the spacecraft, mission and science of JWST.

JWST related content on the NASA HOME PAGE plus links to NASA’s other great activities and missions.


JWST related Missions.


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"First Signs" Tweet Chat
  • FAQs:

  • Vital Facts

    Fact sheet on the JWST Mission.

  • FAQ Lite

    The most popular questions about JWST. (General Public)

  • FAQ Full

    All the major aspects of the JWST Mission are covered here. (General Public)

  • Technical FAQ

    Technical FAQ on a variety of mission issues, aspects and capabilities. (Science/Technical)

  • Solar System Observations FAQ

    Technical FAQ specifically on Solar System observations. (Science/Technical)

During SXSW 2014, we held a tweet-chat with some of the scientists on the"First Signs: Finding Life on Other Planets" panel. Below are a selection of the questions we answered.

The answers are very succint due to Twitter's 140 character limit (and we also added the #FirstSigns hashtag to each answer). Often the questions are rephrased in the answers so that our Twitter followers would know what we were giving the answer to.
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First Signs: Finding Life on Other Planets - SXSW

Q: Of all the Exoplanets discovered, which is the most earth like? (tierrauniversu)

A: I think Kepler-62f is the most earth-like to date. 40% larger, middle of HZ. (Natalie Batalha)

Q: Will JWST be able to further characterize it and what will be needed to detect if there is life in the exoplanets?(tierrauniversu)

A: We will find closer HZ [habitable zone] planets for JWST characterization with TESS and maybe K2 To find evidence of life with JWST, we'll look for by-products of life (bio-markers) in the atmospheres of planets. (Natalie Batalha)

Q: What is the difference betwn Hubble, Chandra, Kepler? (divine_jit)

A: Hubble orbits 350 miles, visible light, and is 2.4m. JWST orbits at 1 million miles, sees IR light, and is 6.5m. Kepler is a planet finder, whereas JWST will be *characterizing* atmospheres of planets by analyzing their spectra. (Jason Kalirai)

Q: What do we expect to see with the JWST that we can't see with the Hubble? (michaelfrye10)

A: JWST will see the 1st stars ever to form in the universe and will be able to find water on other planets. (Alberto Conti)

Q: How is the JWST better than spitzer and other infrared space observatories? (yellowkazooie)

A: JWST has about 50 times the collecting area of Spitzer and the ability to observe at shorter wavelenghth. (Alberto Conti)

Q: Why the heavy focus on the near and mid IR with the science instruments? Why not also target other wavelengths? (alan387)

A: 1) IR can see water in planetary atmospheres, 2) IR can penetrate dust in stellar nurseries, 3 IR can find 1st galaxies. (Jason Kalirai)

Q: Has NASA considered building more Keplers with incremental improvements to overcome issues that shortened life of current SC? (daveonthejob)

A: The next transiting planet finder is already in the works! Check out NASA's TESS mission, to launch in 2017. (Natalie Batalha)

Q: Will we be able to see Europa in any greater detail before a mission there with JWST? (muellerspace)

A: JWST can observe our Solar System at much higher resolution that previous telescopes, optimized for rocky planets. (Alberto Conti)

Q: Will Hubble take Deep Fields in other directions? JWST? (billhoppery)

A: Hubble just started a new program to take such deep fields, Frontier Fields A prelude to JWST.

Q: Is the Universe rate of expansion the same in all directions from the center of the Universe? (billhoppery)

A: The universe is expanding in all directions. JWST will help constrain the rate of expansion by studying dark energy. (Alberto Conti)

Q: I'd like to your favorite of the most recent recent discoveries(any of you) (hawkc83)

A: I would say that it is the Kepler discovery that planets are ubiquitous.  (Jason Kalirai) 715 newly verified exoplanets!! (Natalie Batalha) The recent "planet bonanza" from Kepler! (Amber Staughn)

Q: How is Kepler's data relayed to earth? (paulmollomo)

A: Kepler data is transmitted via Ka-band to the DSN using a fixed antenna. (Natalie Batalha)

Q: Are scientists still trying to confirm Gliese 581g? (coolpool79)

A: Yes! GJ 581 is a high priority target for high precision radial velocity measurements with telescopes like Keck. (Natalie Batalha)

Q: Why the unique design of the JWST as opposed to more traditional telescopes? (michaelfrye10)

A: JWST is optimized to find the faint glow of infrared light. The tennis-court sized sunshield blocks the Sun on one side. And, here is a website with a description of the JWST sunshield.  (Jason Kalirai)

Q: How do you calculate the exact orbit the James Webb will end up in, and how difficult will it be to maintain so far out? (laurl0re)

A: Gravity helps us get there. We use general relativity to calculate the orbit. Once there we can stay for >10 years. (Alberto Conti)

Q: What about the James Webb allows us to see so much further into space than before? (laurl0re)

A: First, its huge light collecting area. JWST will be 100x more powerful than Hubble and can see things fainter than Hubble. Second, as the Universe expands, light gets stretched from the visible to IR. JWST is IR optimized, so its more sensitive.(Jason Kalirai)

Q: How far away is the closest Earth's twin to the Earth? (nimetesra)

A: Kepler-62 is about 1200 light-years away. NASA's TESS mission will find earth-size planets that are nearby. Launch in 2017! Go TESS! (Natalie Batalha)

Q: Could JWST find unknown brown or red dwarf stars closer to us- a lightyear or 2 away? With possible planets around those stars? (jellysock)

A: YES, JWST will be very good for finding nearby ultra cool stars, but we would have already seen something 1-2 ly away. (Jason Kalirai)

Q: As the planets are pretty far away, how would we go there and build a settlement? (divine_jit)

A: We don't yet have the technology to get us there, but the first step is to find the habitable planets! (Amber Straughn)

Q: If the JWST could see visible light and is pointed towards Earth, whats the smallest thing it could see on the surface? (jon889)

A: At a distance of 1 million miles, a pixel on JWST subtends about 220 meters. (Jason Kalirai) However, JWST will never point back towards Earth (and the Sun!); will always point to deep space. (Amber Straugn)

Q: So will JWST be able to see through the ice/surface on Europa to see more definitively if there is liquid water there? (muellerspace)

A: Certainly indirect evidence as was done with Hubble. (Natalie Batalha)

Q: Isn't presence of magnetic field critical in search for habitable planets? (hitchens)

A: Magnetic fields are not ciritical for the detection of exoplanets but may be critical for life. My guess is that we'll find evidence of life before making measurements of exoplanet properties like magnetic fields. (Natalie Batalha)

Q: As moons are very common in our solar system (especially around the gas giants), is there any hope to find exomoons someday? (astrochemia)

A: Yes! Teams are actively looking for exomoons in Kepler data. (Natalie Baltalha)

Q: What's the highest priority research for JWST? What is the line like to get telescope time? Full but prioritizing? (ramsayphil)

A: Like Hubble, JWST telescope time will be competed and peer-review selected. Expect ~10% of the best proposals to get time. (Jason Kalirai)

Q: How many planets are in the Alpha Centauri system and Proxima Centauri? (siscorane)

A: Indications of one so far: alpha Cen Bb (Natalie Batalha)

Q: What happened to 22b? (coolpool29)

A: Don't give up on 22b! She's larger which implies she has a H/He envelope of some sort instead of a rocky surface. (Natalie Batalha)