Webb telescope reaches destination

The space telescope has reached its destination of the second Lagrange point.

The mirrors on the space observatory must still be meticulously aligned and the infrared detectors sufficiently chilled before science observations can begin in June. But flight controllers in Baltimore were euphoric after chalking up another success.

“We’re one step closer to uncovering the mysteries of the universe. And I can’t wait to see Webb’s first new views of the universe this summer!” the Nasa administrator, Bill Nelson, said in a statement.

“Wow, what a ride this last month it’s been,” said Amber Straughn, a deputy project scientist for Nasa.

The telescope has been described as a “time machine” by scientists and will enable astronomers to peer back further in time than ever before, all the way back to when the first stars and galaxies were forming 13.7bn years ago. That’s a mere 100m years from the Big Bang, when the universe was created.

The Webb will also hunt for signs of extraterrestrial life.

Considered the successor to the Hubble, which orbits 330 miles (530km) up, the Webb is too far away for emergency repairs. That makes the milestones over the past month – and the ones ahead – all the more critical.

Whether chasing optical and ultraviolet light like the Hubble or infrared light like the Webb, telescopes can see farther and more clearly when operating above Earth’s distorting atmosphere. That’s why Nasa teamed up with the European and Canadian space agencies to get Webb and its massive mirror – the largest ever launched – out into the cosmos.

So far, things have gone really smoothly for this highly complicated mission but there are still challenges ahead. One can only hope that now that the major hurdles have been overcome, especially the whole business of unfolding of a tennis court size structure from the small confines of a rocket nose cone, that some small glitch does not ruin things.

The whole operation reflects great credit on all the engineers and scientists who were involved in designing, building, and launching it.


  1. Matt G says

    JWST has been living a charmed life.

    Did anyone see Bill Nelson’s scripted address after the successful launch? About a third of it was a Christian sermon, it being December 25th. Nauseating.

  2. DonDueed says

    One thing I’ve wondered about but haven’t seen addressed is the issue of communication with the JWST.

    The second Lagrange point is opposite the Moon from Earth. One would think that the signal path between ground stations and JWST would be blocked, at least some of the time.

    So what allows us to stay in communication? I know the telescope orbits L2 rather than sitting at one specific spot all the time. Is that what brings it out of eclipse enough to stay in touch?

  3. Rob Grigjanis says

    DonDueed @2: The 2nd sun-Earth Lagrange point (the relevant one here) is on the other side of Earth from the sun.

  4. Mano Singham says

    DonDueed @#2,

    Good question! I did a rough calculation to see what the blocking size might be, assuming that the Earth, Moon and Webb are in a perfect straight line all the time which you point out is not exactly the case.

    The diameter of the Moon is 3,475 km. The distance of the. Moon from the Earth is 384,400 km while the Webb is 1.5 million km away. Using similar triangles, the Moon will block out a circle on the Earth of diameter 1500000*3475/(1500000-384400) which works out to 4,762 km.

    The diameter of the Earth is 12,756 km, so the Moon only blocks about a third of the Earth’s diameter (or about 13% of the Earth’s surface that is facing Webb) from receiving direct signals from the Webb. I am sure that there are receivers all over the Earth.

    On the other hand, there may be a simpler explanation that I am not aware of!

  5. Rob Grigjanis says

    You guys seem to be talking about the Earth-Moon 2nd Lagrange point. JWST is at the Sun-Earth 2nd Lagrange point. It’s Sun, Earth and Webb which would be roughly aligned.

    A notable example of a spacecraft at L2 is the James Webb Space Telescope, designed to operate near the Earth–Sun L2.[7] See other spacecraft at Sun–Earth L2.

  6. John Morales says

    People still don’t seem to get the internet.

    Communicating with Webb

    Webb’s position out at L2 also makes it easy for us to talk to it. Since it will always be at the same location relative to Earth-in the midnight sky about 1.5 million km away -- we can have continuous communications with it as the Earth rotates through the Deep Space Network (DSN), using three large antennas on the ground located in Australia, Spain and California.


  7. Rob Grigjanis says

    lorn @7: It was a collaboration between NASA and the European and Canadian Space Agencies.

  8. DonDueed says

    Aha! Thanks Rob and John. That explains a lot — not just the communication issue but also why the JWST parking place is so far beyond the Moon’s orbit.

  9. lorn says

    Rob Grigjanis @8: It was a collaboration between NASA and the European and Canadian Space Agencies.

    Well that explains it.

    My memory isn’t what it was but weren’t Americans once known as the ‘go-to to get stuff done’ people’?

Leave a Reply

Your email address will not be published. Required fields are marked *